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Sample records for explosive chemistry simulating

  1. Explosive simulants for testing explosive detection systems

    Science.gov (United States)

    Kury, John W.; Anderson, Brian L.

    1999-09-28

    Explosives simulants that include non-explosive components are disclosed that facilitate testing of equipment designed to remotely detect explosives. The simulants are non-explosive, non-hazardous materials that can be safely handled without any significant precautions. The simulants imitate real explosives in terms of mass density, effective atomic number, x-ray transmission properties, and physical form, including moldable plastics and emulsions/gels.

  2. Shock-induced explosive chemistry in a deterministic sample configuration.

    Energy Technology Data Exchange (ETDEWEB)

    Stuecker, John Nicholas; Castaneda, Jaime N.; Cesarano, Joseph, III (,; ); Trott, Wayne Merle; Baer, Melvin R.; Tappan, Alexander Smith

    2005-10-01

    Explosive initiation and energy release have been studied in two sample geometries designed to minimize stochastic behavior in shock-loading experiments. These sample concepts include a design with explosive material occupying the hole locations of a close-packed bed of inert spheres and a design that utilizes infiltration of a liquid explosive into a well-defined inert matrix. Wave profiles transmitted by these samples in gas-gun impact experiments have been characterized by both velocity interferometry diagnostics and three-dimensional numerical simulations. Highly organized wave structures associated with the characteristic length scales of the deterministic samples have been observed. Initiation and reaction growth in an inert matrix filled with sensitized nitromethane (a homogeneous explosive material) result in wave profiles similar to those observed with heterogeneous explosives. Comparison of experimental and numerical results indicates that energetic material studies in deterministic sample geometries can provide an important new tool for validation of models of energy release in numerical simulations of explosive initiation and performance.

  3. Computer simulation of explosion crater in dams with different buried depths of explosive

    Science.gov (United States)

    Zhang, Zhichao; Ye, Longzhen

    2018-04-01

    Based on multi-material ALE method, this paper conducted a computer simulation on the explosion crater in dams with different buried depths of explosive using LS-DYNA program. The results turn out that the crater size increases with the increase of buried depth of explosive at first, but closed explosion cavity rather than a visible crater is formed when the buried depth of explosive increases to some extent. The soil in the explosion cavity is taken away by the explosion products and the soil under the explosion cavity is compressed with its density increased. The research can provide some reference for the anti-explosion design of dams in the future.

  4. Chemistry and Explosives: An Approach to the Topic through an Artistic and Historical Contribution Made by a Spanish Global Explosives Supplier

    Science.gov (United States)

    Pinto, Gabriel; Garrido-Escudero, Amalio

    2016-01-01

    We present ideas about how to incorporate discussion of a paintings collection in chemistry classrooms. Specifically, it is a collection of paintings that have illustrated calendars since 1900, from a traditional Spanish explosives company (founded by Alfred Nobel and now known as Maxam). The case is discussed in relation to the "chemistry in…

  5. Chemistry resolved kinetic flow modeling of TATB based explosives

    Science.gov (United States)

    Vitello, Peter; Fried, Laurence E.; William, Howard; Levesque, George; Souers, P. Clark

    2012-03-01

    Detonation waves in insensitive, TATB-based explosives are believed to have multiple time scale regimes. The initial burn rate of such explosives has a sub-microsecond time scale. However, significant late-time slow release in energy is believed to occur due to diffusion limited growth of carbon. In the intermediate time scale concentrations of product species likely change from being in equilibrium to being kinetic rate controlled. We use the thermo-chemical code CHEETAH linked to an ALE hydrodynamics code to model detonations. We term our model chemistry resolved kinetic flow, since CHEETAH tracks the time dependent concentrations of individual species in the detonation wave and calculates EOS values based on the concentrations. We present here two variants of our new rate model and comparison with hot, ambient, and cold experimental data for PBX 9502.

  6. Development of steam explosion simulation code JASMINE

    Energy Technology Data Exchange (ETDEWEB)

    Moriyama, Kiyofumi; Yamano, Norihiro; Maruyama, Yu; Kudo, Tamotsu; Sugimoto, Jun [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Nagano, Katsuhiro; Araki, Kazuhiro

    1995-11-01

    A steam explosion is considered as a phenomenon which possibly threatens the integrity of the containment vessel of a nuclear power plant in a severe accident condition. A numerical calculation code JASMINE (JAeri Simulator for Multiphase INteraction and Explosion) purposed to simulate the whole process of steam explosions has been developed. The premixing model is based on a multiphase flow simulation code MISTRAL by Fuji Research Institute Co. In JASMINE code, the constitutive equations and the flow regime map are modified for the simulation of premixing related phenomena. The numerical solution method of the original code is succeeded, i.e. the basic equations are discretized semi-implicitly, BCGSTAB method is used for the matrix solver to improve the stability and convergence, also TVD scheme is applied to capture a steep phase distribution accurately. Test calculations have been performed for the conditions correspond to the experiments by Gilbertson et al. and Angelini et al. in which mixing of solid particles and water were observed in iso-thermal condition and with boiling, respectively. (author).

  7. Development of steam explosion simulation code JASMINE

    International Nuclear Information System (INIS)

    Moriyama, Kiyofumi; Yamano, Norihiro; Maruyama, Yu; Kudo, Tamotsu; Sugimoto, Jun; Nagano, Katsuhiro; Araki, Kazuhiro.

    1995-11-01

    A steam explosion is considered as a phenomenon which possibly threatens the integrity of the containment vessel of a nuclear power plant in a severe accident condition. A numerical calculation code JASMINE (JAeri Simulator for Multiphase INteraction and Explosion) purposed to simulate the whole process of steam explosions has been developed. The premixing model is based on a multiphase flow simulation code MISTRAL by Fuji Research Institute Co. In JASMINE code, the constitutive equations and the flow regime map are modified for the simulation of premixing related phenomena. The numerical solution method of the original code is succeeded, i.e. the basic equations are discretized semi-implicitly, BCGSTAB method is used for the matrix solver to improve the stability and convergence, also TVD scheme is applied to capture a steep phase distribution accurately. Test calculations have been performed for the conditions correspond to the experiments by Gilbertson et al. and Angelini et al. in which mixing of solid particles and water were observed in iso-thermal condition and with boiling, respectively. (author)

  8. Simulation of explosive welding with ANFO mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Mousavi, A.A. Akbari; Burley, Stephen J.; Al-Hassani, S.T.S. [Department of Mechanical, Aerospace and Manufacturing Engineering, UMIST, PO Box 88, Manchester M60 1QD (United Kingdom); Byers Brown, W. [Mass Action Research Consultancy, Devonshire House, 14 Corbar Road, Buxton, SK17 6RQ (United Kingdom)

    2004-06-01

    The work described here arose from a study into explosive welding. As part of that study, the impact velocity of stainless steel and titanium plates to grazing detonation of ANFO/perlite, the velocity of detonation were measured. Computer simulation required a new model which copes with an equation of state of low explosives. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

  9. Mesoscale meteorological model based on radioactive explosion cloud simulation

    International Nuclear Information System (INIS)

    Zheng Yi; Zhang Yan; Ying Chuntong

    2008-01-01

    In order to simulate nuclear explosion and dirty bomb radioactive cloud movement and concentration distribution, mesoscale meteorological model RAMS was used. Particles-size, size-active distribution and gravitational fallout in the cloud were considered. The results show that the model can simulate the 'mushroom' clouds of explosion. Three-dimension fluid field and radioactive concentration field were received. (authors)

  10. Numerical Simulation of Explosive Forming Using Detonating Fuse

    Directory of Open Access Journals (Sweden)

    H Iyama

    2017-09-01

    Full Text Available The explosive forming is a characteristic method. An underwater shock wave is generated by underwater explosion of an explosive. A metal plate is affected high strain rate by the shock loading and is formed along a metal die. Although this method has the advantage of mirroring the shape of the die, a free forming was used in this paper. An expensive metal die is not necessary for this free forming. It is possible that a metal plate is formed with simple supporting parts. However, the forming shape is depend on the shock pressure distribution act on the metal plate. This pressure distribution is able to change by the shape of explosive, a mass of explosive and a shape of pressure vessel. On the other hand, we need the pressure vessel for food processing by the underwater shock wave. Therefore, we propose making the pressure vessel by this explosive forming. One design suggestion of pressure vessel made of stainless steel was considered. However, we cannot decide suitable conditions, the mass of the explosive and the distance between the explosive and the metal plate to make the pressure vessel. In order to decide these conditions, we have tried the numerical simulation on this explosive forming. The basic simulation method was ALE (Arbitrary Laglangian Eulerian method including with Mie-Grümeisen EOS (equation of state, JWL EOS, Johnson-Cook constitutive equation for a material model. In this paper, the underwater pressure contours to clear the propagations of the underwater shock wave, forming processes and deformation velocity of the metal plate is shown and it will be discussed about those results.

  11. Simulation of first SERENA KROTOS steam explosion experiment

    International Nuclear Information System (INIS)

    Leskovar, Matjaz; Ursic, Mitja

    2009-01-01

    A steam explosion may occur when, during a severe reactor accident, the molten core comes into contact with the coolant water. A strong enough steam explosion in a nuclear power plant could jeopardize the containment integrity and so lead to a direct release of radioactive material to the environment. To resolve the open issues in steam explosion understanding and modeling, the OECD program SERENA Phase 2 was launched at the end of year 2007, focusing on nuclear applications. SERENA comprises an experimental program, which is being carried out in the complementary KROTOS and TROI corium facilities, accompanied by a comprehensive analytical program, where also pre- and post-test calculations are foreseen. In the paper the sensitivity post-test calculations of the first SERENA KROTOS experiment KS-1, which were performed with the code MC3D, are presented and discussed. Since the results of the SERENA tests are restricted to SERENA members, only the various calculation results are given, not comparing them to experimental measurements. Various premixing and explosion simulations were performed on a coarse and a fine numerical mesh, applying two different jet breakup models (global, local) and varying the minimum bubble diameter in the explosion simulations (0.5 mm, 5 mm). The simulations revealed that all varied parameters have a significant influence on the calculation results, as was expected since the fuel coolant interaction process is a highly complex phenomenon. The results of the various calculations are presented in comparison and the observed differences are discussed and explained. (author)

  12. Introduction to Physics and Chemistry of Combustion Explosion, Flame, Detonation

    CERN Document Server

    Liberman, Michael A

    2008-01-01

    Most of the material covered in this book deals with the fundamentals of chemistry and physics of key processes and fundamental mechanisms for various combustion and combustion related phenomena in gaseous combustible mixture. It provides the reader with basic knowledge of burning processes and mechanisms of reaction wave propagation. The combustion of a gas mixture (flame, explosion, detonation) is necessarily accompanied by motion of the gas. The process of combustion is therefore not only a chemical phenomenon but also one of gas dynamics. The material selection focuses on the gas phase and

  13. Numerical Simulation on Smoke Spread and Temperature Distribution in a Corn Starch Explosion

    Science.gov (United States)

    Lin, CherngShing; Hsu, JuiPei

    2018-01-01

    It is discovered from dust explosion accidents in recent years that deep causes of the accidents lies in insufficient cognition of dust explosion danger, and no understanding on danger and information of the dust explosion. In the study, Fire Dynamics Simulator (FDS) evaluation tool is used aiming at Taiwan Formosa Fun Coast explosion accidents. The calculator is used for rebuilding the explosion situation. The factors affecting casualties under explosion are studied. The injured personnel participating in the party are evaluated according to smoke diffusion and temperature distribution for numerical simulation results. Some problems noted in the fire disaster after actual explosion are proposed, rational site analysis is given, thereby reducing dust explosion risk grade.

  14. Design and validation of inert homemade explosive simulants for X-ray-based inspection systems

    Science.gov (United States)

    Faust, Anthony A.; Nacson, Sabatino; Koffler, Bruce; Bourbeau, Éric; Gagne, Louis; Laing, Robin; Anderson, C. J.

    2014-05-01

    Transport Canada (TC), the Canadian Armed Forces, and other public security agencies have an interest in the assessment of the potential utility of advanced explosives detection technologies to aid in the detection and interdiction of commercial grade, military grade, and homemade or improvised explosives (HME or IE). The availability of suitable, non-hazardous, non-toxic, explosive simulants is of concern when assessing the potential utility of such detection systems. Lack of simulants limits the training opportunities, and ultimately the detection probability, of security personnel using these systems. While simulants for commercial and military grade explosives are available for a wide variety of detection technologies, the design and production of materials to simulate improvised explosives has not kept pace with this emerging threat. Funded by TC and the Canadian Safety and Security Program, Defence Research and Development Canada (DRDC), Visiontec Systems, and Optosecurity engaged in an effort to develop inert, non-toxic Xray interrogation simulants for IE materials such as ammonium nitrate, potassium chlorate, and triacetone triperoxide. These simulants were designed to mimic key X-ray interrogation-relevant material properties of real improvised explosives, principally their bulk density and effective atomic number. Different forms of the simulants were produced and tested, simulating the different explosive threat formulations that could be encountered by front line security workers. These simulants comply with safety and stability requirements, and as best as possible match form and homogeneity. This paper outlines the research program, simulant design, and validation.

  15. Multi-dimensional simulations of core-collapse supernova explosions with CHIMERA

    Science.gov (United States)

    Messer, O. E. B.; Harris, J. A.; Hix, W. R.; Lentz, E. J.; Bruenn, S. W.; Mezzacappa, A.

    2018-04-01

    Unraveling the core-collapse supernova (CCSN) mechanism is a problem that remains essentially unsolved despite more than four decades of effort. Spherically symmetric models with otherwise high physical fidelity generally fail to produce explosions, and it is widely accepted that CCSNe are inherently multi-dimensional. Progress in realistic modeling has occurred recently through the availability of petascale platforms and the increasing sophistication of supernova codes. We will discuss our most recent work on understanding neutrino-driven CCSN explosions employing multi-dimensional neutrino-radiation hydrodynamics simulations with the Chimera code. We discuss the inputs and resulting outputs from these simulations, the role of neutrino radiation transport, and the importance of multi-dimensional fluid flows in shaping the explosions. We also highlight the production of 48Ca in long-running Chimera simulations.

  16. USSR Report Chemistry

    National Research Council Canada - National Science Library

    1986-01-01

    Contents: Adsorption, Chemistry,Alkaloids, Analytical Chemistry, Catalysis,Chemical Industry,,Coal Gasification, Combustion, Electrochemistry,Explosives and Explosions, Fertilizers, Free Radicals, Inorganic...

  17. Novel high-fidelity realistic explosion damage simulation for urban environments

    Science.gov (United States)

    Liu, Xiaoqing; Yadegar, Jacob; Zhu, Youding; Raju, Chaitanya; Bhagavathula, Jaya

    2010-04-01

    Realistic building damage simulation has a significant impact in modern modeling and simulation systems especially in diverse panoply of military and civil applications where these simulation systems are widely used for personnel training, critical mission planning, disaster management, etc. Realistic building damage simulation should incorporate accurate physics-based explosion models, rubble generation, rubble flyout, and interactions between flying rubble and their surrounding entities. However, none of the existing building damage simulation systems sufficiently faithfully realize the criteria of realism required for effective military applications. In this paper, we present a novel physics-based high-fidelity and runtime efficient explosion simulation system to realistically simulate destruction to buildings. In the proposed system, a family of novel blast models is applied to accurately and realistically simulate explosions based on static and/or dynamic detonation conditions. The system also takes account of rubble pile formation and applies a generic and scalable multi-component based object representation to describe scene entities and highly scalable agent-subsumption architecture and scheduler to schedule clusters of sequential and parallel events. The proposed system utilizes a highly efficient and scalable tetrahedral decomposition approach to realistically simulate rubble formation. Experimental results demonstrate that the proposed system has the capability to realistically simulate rubble generation, rubble flyout and their primary and secondary impacts on surrounding objects including buildings, constructions, vehicles and pedestrians in clusters of sequential and parallel damage events.

  18. Numerical Simulation of the Micro-explosion during Ho:YAG laser lithotripsy

    International Nuclear Information System (INIS)

    Yao Yucheng; Huang Chuyun; Xu Guowang; Yan Xudong; Wang Yanlin

    2011-01-01

    The micro-explosion during Ho:YAG laser lithotripsy may cause calculus fragmentation and migration. It plays an important role to the surgery. A numerical simulation of the micro-explosion during Ho:YAG laser lithotripsy has been developed. The explosion problem in water environment was solved by the Euler algorithm and the piecewise parabolic method (PPM) was selected in the calculation. This simulation investigated the explosion dynamics evolution in the lithotripsy area. The pressure and intensity of the calculus surface were calculated for different laser pulse energy and different distance between calculus and fiber tip. The calculation results indicate that the micro-explosion's properties are determined by the pulse energy, pulse duration and the water distance. Though Short pulse duration and large pulse energy cause high ablation efficiency, it mains more calculus retropulsion at the same time. The ideal surgery results need property laser parameters.

  19. Steam explosion simulation code JASMINE v.3 user's guide

    International Nuclear Information System (INIS)

    Moriyama, Kiyofumi; Maruyama, Yu; Nakamura, Hideo

    2008-07-01

    A steam explosion occurs when hot liquid contacts with cold volatile liquid. In this phenomenon, fine fragmentation of the hot liquid causes extremely rapid heat transfer from the hot liquid to the cold volatile liquid, and explosive vaporization, bringing shock waves and destructive forces. The steam explosion due to the contact of the molten core material and coolant water during severe accidents of light water reactors has been regarded as a potential threat to the integrity of the containment vessel. We developed a mechanistic steam explosion simulation code, JASMINE, that is applicable to plant scale assessment of the steam explosion loads. This document, as a manual for users of JASMINE code, describes the models, numerical solution methods, and also some verification and example calculations, as well as practical instructions for input preparation and usage of the code. (author)

  20. Comparing CTH simulations and experiments on explosively loaded rings

    Science.gov (United States)

    Braithwaite, C. H.; Aydelotte, Brady; Collins, Adam; Thadhani, Naresh; Williamson, David Martin

    2012-03-01

    A series of experiments were conducted on explosively loaded metallic rings for the purpose of studying fragmentation. In addition to the collection of fragments for analysis, the radial velocity of the expanding ring was measured with photon Doppler velocimetry (PDV) and the arrangement was imaged using high speed photography. Both the ring material and the material used as the explosive container were altered and the results compared with simulations performed in CTH. Good agreement was found between the simulations and the experiments. The maximum radial velocity attained was approximately 380 m/s, which was achieved through loading with a 5g PETN based charge.

  1. Molecular dynamics simulation of bubble nucleation in explosive boiling

    International Nuclear Information System (INIS)

    Zou Yu; Chinese Academy of Sciences, Beijing; Huai Xiulan; Liang Shiqiang

    2009-01-01

    Molecular dynamics (MD) simulation is carried out for the bubble nucleation of liquid nitrogen in explosive boiling. The heat is transferred into the simulation system by rescaling the velocity of the molecules. The results indicate that the initial equilibrium temperature of liquid and molecular cluster size affect the energy conversion in the process of bubble nucleation. The potential energy of the system violently varies at the beginning of the bubble nucleation, and then varies around a fixed value. At the end of bubble nucleation, the potential energy of the system slowly increases. In the bubble nucleation of explosive boiling, the lower the initial equilibrium temperature, the larger the size of the molecular cluster, and the more the heat transferred into the system of the simulation cell, causing the increase potential energy in a larger range. (authors)

  2. Source characterization of underground explosions from hydrodynamic-to-elastic coupling simulations

    Science.gov (United States)

    Chiang, A.; Pitarka, A.; Ford, S. R.; Ezzedine, S. M.; Vorobiev, O.

    2017-12-01

    A major improvement in ground motion simulation capabilities for underground explosion monitoring during the first phase of the Source Physics Experiment (SPE) is the development of a wave propagation solver that can propagate explosion generated non-linear near field ground motions to the far-field. The calculation is done using a hybrid modeling approach with a one-way hydrodynamic-to-elastic coupling in three dimensions where near-field motions are computed using GEODYN-L, a Lagrangian hydrodynamics code, and then passed to WPP, an elastic finite-difference code for seismic waveform modeling. The advancement in ground motion simulation capabilities gives us the opportunity to assess moment tensor inversion of a realistic volumetric source with near-field effects in a controlled setting, where we can evaluate the recovered source properties as a function of modeling parameters (i.e. velocity model) and can provide insights into previous source studies on SPE Phase I chemical shots and other historical nuclear explosions. For example the moment tensor inversion of far-field SPE seismic data demonstrated while vertical motions are well-modeled using existing velocity models large misfits still persist in predicting tangential shear wave motions from explosions. One possible explanation we can explore is errors and uncertainties from the underlying Earth model. Here we investigate the recovered moment tensor solution, particularly on the non-volumetric component, by inverting far-field ground motions simulated from physics-based explosion source models in fractured material, where the physics-based source models are based on the modeling of SPE-4P, SPE-5 and SPE-6 near-field data. The hybrid modeling approach provides new prospects in modeling explosion source and understanding the uncertainties associated with it.

  3. Gasdynamic Model of Turbulent Combustion in TNT Explosions

    Energy Technology Data Exchange (ETDEWEB)

    Kuhl, A L; Bell, J B; Beckner, V E

    2010-01-08

    A model is proposed to simulate turbulent combustion in confined TNT explosions. It is based on: (i) the multi-component gasdynamic conservation laws, (ii) a fast-chemistry model for TNT-air combustion, (iii) a thermodynamic model for frozen reactants and equilibrium products, (iv) a high-order Godunov scheme providing a non-diffusive solution of the governing equations, and (v) an ILES approach whereby adaptive mesh refinement is used to capture the energy bearing scales of the turbulence on the grid. Three-dimensional numerical simulations of explosion fields from 1.5-g PETN/TNT charges were performed. Explosions in six different chambers were studied: three calorimeters (volumes of 6.6-l, 21.2-l and 40.5-l with L/D = 1), and three tunnels (L/D = 3.8, 4.65 and 12.5 with volumes of 6.3-l) - to investigate the influence of chamber volume and geometry on the combustion process. Predicted pressures histories were quite similar to measured pressure histories for all cases studied. Experimentally, mass fraction of products, Y{sub p}{sup exp}, reached a peak value of 88% at an excess air ratio of twice stoichiometric, and then decayed with increasing air dilution; mass fractions Y{sub p}{sup calc} computed from the numerical simulations followed similar trends. Based on this agreement, we conclude that the dominant effect that controls the rate of TNT combustion with air is the turbulent mixing rate; the ILES approach along with the fast-chemistry model used here adequately captures this effect.

  4. Determine the feasibility of techniques for simulating coal dust explosions

    CSIR Research Space (South Africa)

    Kirsten, JT

    1994-07-01

    Full Text Available The primary objective of this work is to assess the feasibility of reliably simulating the coal dust explosion process taking place in the Kloppersbos tunnel with a computer model. Secondary objectives are to investigate the viability of simulating...

  5. On the adequacy of numerical codes for the simulation of vapour cloud explosions

    International Nuclear Information System (INIS)

    Wingerden, G.J.M.v.; Berg, A.C.v.d.

    1984-01-01

    Three spherically symmetric blast simulation codes have been evaluated: a low-flame-speed model (Piston model) and two gasdynamic blast simulation codes (BLAST and CLOUD). Self-similar flow fields in front of constant velocity flames and large- and small-scale spherically symmetric explosions experiments were simulated. The Piston model can be used for the simulation of spherically symmetric explosions at flame speeds -1 whereas BLAST and CLOUD are adequate for flame speeds exceeding 100 ms -1 . An adapted Piston code has been investigated with respect to the capability of simulating blast due to explosions of pancake-shaped clouds. Comparison to an acoustic approach showed that the Piston model can be regarded as an acoustic model with the possibility of handling every imaginable flame path. The research was part of the indirect action research programme on LWR Safety of the Commission of the European Communities. (project 12B, contract 008 SRN)

  6. Modelling and simulation of gas explosions in complex geometries

    Energy Technology Data Exchange (ETDEWEB)

    Saeter, Olav

    1998-12-31

    This thesis presents a three-dimensional Computational Fluid Dynamics (CFD) code (EXSIM94) for modelling and simulation of gas explosions in complex geometries. It gives the theory and validates the following sub-models : (1) the flow resistance and turbulence generation model for densely packed regions, (2) the flow resistance and turbulence generation model for single objects, and (3) the quasi-laminar combustion model. It is found that a simple model for flow resistance and turbulence generation in densely packed beds is able to reproduce the medium and large scale MERGE explosion experiments of the Commission of European Communities (CEC) within a band of factor 2. The model for a single representation is found to predict explosion pressure in better agreement with the experiments with a modified k-{epsilon} model. This modification also gives a slightly improved grid independence for realistic gas explosion approaches. One laminar model is found unsuitable for gas explosion modelling because of strong grid dependence. Another laminar model is found to be relatively grid independent and to work well in harmony with the turbulent combustion model. The code is validated against 40 realistic gas explosion experiments. It is relatively grid independent in predicting explosion pressure in different offshore geometries. It can predict the influence of ignition point location, vent arrangements, different geometries, scaling effects and gas reactivity. The validation study concludes with statistical and uncertainty analyses of the code performance. 98 refs., 96 figs, 12 tabs.

  7. Development of compressible density-based steam explosion simulation code ESE-2

    International Nuclear Information System (INIS)

    Leskovar, M.

    2004-01-01

    A steam explosion is a fuel coolant interaction process by which the energy of the corium is transferred to water in a time-scale smaller than the time-scale for system pressure relief and induces dynamic loading of surrounding structures. A strong enough steam explosion in a nuclear power plant could jeopardize the containment integrity and so lead to a direct release of radioactive material to the environment. To help finding answers on open questions regarding steam explosion understanding and modelling, the steam explosion simulation code ESE-2 is being developed. In contrast to the developed simulation code ESE-1, where the multiphase flow equations are solved with pressure-based numerical methods (best suited for incompressible flow), in ESE-2 densitybased numerical methods (best suited for compressible flow) are used. Therefore ESE-2 will enable an accurate treatment of the whole steam explosion process, which consists of the premixing, triggering, propagation and expansion phase. In the paper the basic characteristics of the mathematical model and the numerical solution procedure in ESE-2 are described. The essence of the numerical treatment is that the convective terms in the multiphase flow equations are calculated with the AUSM+ scheme, which is very time efficient since no field-by-field wave decomposition is needed, using second order accurate discretization. (author)

  8. USSR Report, Chemistry

    National Research Council Canada - National Science Library

    1986-01-01

    This USSR Report on Chemistry contains articles on Aerosols, Adsorption, Biochemistry, Catalysis, Chemical Industry, Coal Gasification, Electrochemistry, Explosives and Explosions, Fertilizers, Food...

  9. Simulation of steam explosion in stratified melt-coolant configuration

    International Nuclear Information System (INIS)

    Leskovar, Matjaž; Centrih, Vasilij; Uršič, Mitja

    2016-01-01

    Highlights: • Strong steam explosions may develop spontaneously in stratified configurations. • Considerable melt-coolant premixed layer formed in subcooled water with hot melts. • Analysis with MC3D code provided insight into stratified steam explosion phenomenon. • Up to 25% of poured melt was mixed with water and available for steam explosion. • Better instrumented experiments needed to determine dominant mixing process. - Abstract: A steam explosion is an energetic fuel coolant interaction process, which may occur during a severe reactor accident when the molten core comes into contact with the coolant water. In nuclear reactor safety analyses steam explosions are primarily considered in melt jet-coolant pool configurations where sufficiently deep coolant pool conditions provide complete jet breakup and efficient premixture formation. Stratified melt-coolant configurations, i.e. a molten melt layer below a coolant layer, were up to now believed as being unable to generate strong explosive interactions. Based on the hypothesis that there are no interfacial instabilities in a stratified configuration it was assumed that the amount of melt in the premixture is insufficient to produce strong explosions. However, the recently performed experiments in the PULiMS and SES (KTH, Sweden) facilities with oxidic corium simulants revealed that strong steam explosions may develop spontaneously also in stratified melt-coolant configurations, where with high temperature melts and subcooled water conditions a considerable melt-coolant premixed layer is formed. In the article, the performed study of steam explosions in a stratified melt-coolant configuration in PULiMS like conditions is presented. The goal of this analytical work is to supplement the experimental activities within the PULiMS research program by addressing the key questions, especially regarding the explosivity of the formed premixed layer and the mechanisms responsible for the melt-water mixing. To

  10. Material properties influence on steam explosion efficiency. Prototypic versus simulant melts, eutectic versus non-eutectic melts

    International Nuclear Information System (INIS)

    Leskovar, M.; Mavko, B.

    2006-01-01

    A steam explosion may occur during a severe nuclear reactor accident if the molten core comes into contact with the coolant water. A strong enough steam explosion in a nuclear power plant could jeopardize the containment integrity and so lead to a direct release of radioactive material to the environment. Details of processes taking place prior and during the steam explosion have been experimentally studied for a number of years with adjunct efforts in modelling these processes to address the scaling of these experiments. Steam explosion experiments have shown that there are important differences of behaviour between simulant and prototypical melts, and that also at prototypical melts the fuel coolant interactions depend on the composition of the corium. In experiments with prototypic materials no spontaneous steam explosions occurred (except with an eutectic composition), whereas with simulant materials the steam explosions were triggered spontaneously. The energy conversion ratio of steam explosions with prototypic melts is at least one order of magnitude lower than the energy conversion ratio of steam explosions with simulant melts. Although the different behaviour of prototypic and simulant melts has been known for a number of years, there is no reliable explanation for these differences. Consequently it is not possible to reliably estimate whether corium would behave so non-explosive also in reactor conditions, where the mass of poured melt is nearly three orders of magnitude larger than in experimental conditions. An even more fascinating material effect was observed recently at corium experiments with eutectic and non-eutectic compositions. It turned out that eutectic corium always exploded spontaneously, whereas non-eutectic corium never exploded spontaneously. In the paper, a possible explanation of both material effects (prototypic/simulant melts, eutectic/non-eutectic corium) on the steam explosion is provided. A model for the calculation of the

  11. Simulation of small-scale coronal explosives due to magnetic reconnections

    International Nuclear Information System (INIS)

    Fan Quanlin; Feng Xueshang; Xiang Changqing; Zhong Dingkun

    2003-01-01

    The dynamics of small-scale explosive phenomena in the lower corona have been simulated by solving the compressible magnetohydrodynamic equations. Numerical results show that the magnetic reconnections in a long coronal current sheet consist of a series of discrete small reconnection events, coalescence of magnetic islands, and plasmoid ejections, corresponding to the explosive events occurring intermittently and as bursts in a mentioned observational case. The generation of magnetic islands via multiple-X-point reconnection and their coalescence processes, to some extent, are qualitatively similar to the sequence of brightenings in the active region NOAA 8668. The strong ejections are possibly related to the recorded extreme ultraviolet (EUV) emitting structures. Morphological comparison and quantitative check of the plasma parameters support this candidate mechanism, and the idea that explosive events that appear to last long may not be single events, but a succession of explosive events either resolved or unresolved. The temporal energy conversion process is also examined

  12. TWO-DIMENSIONAL SIMULATIONS OF EXPLOSIVE ERUPTIONS OF KICK-EM JENNY AND OTHER SUBMARINE VOLCANOS

    Directory of Open Access Journals (Sweden)

    Galen Gisler

    2006-01-01

    Full Text Available Kick-em Jenny, in the Eastern Caribbean, is a submerged volcanic cone that has erupted a dozen or more times since its discovery in 1939. The most likely hazard posed by this volcano is to shipping in the immediate vicinity (through volcanic missiles or loss-of-buoyancy, but it is of interest to estimate upper limits on tsunamis that might be produced by a catastrophic explosive eruption. To this end, we have performed two-dimensional simulations of such an event in a geometry resembling that of Kick-em Jenny with our SAGE adaptive mesh Eulerian multifluid compressible hydrocode. We use realistic equations of state for air, water, and basalt, and follow the event from the initial explosive eruption, through the generation of a transient water cavity and the propagation of waves away from the site. We find that even for extremely catastrophic explosive eruptions, tsunamis from Kick-em Jenny are unlikely to pose significant danger to nearby islands. For comparison, we have also performed simulations of explosive eruptions at the much larger shield volcano Vailulu'u in the Samoan chain, where the greater energy available can produce a more impressive wave. In general, however, we conclude that explosive eruptions do not couple well to water waves. The waves that are produced from such events are turbulent and highly dissipative, and don't propagate well. This is consistent with what we have found previously in simulations of asteroid-impact generated tsunamis. Non-explosive events, however, such as landslides or gas hydrate releases, do couple well to waves, and our simulations of tsunamis generated by sub- aerial and sub-aqueous landslides demonstrate this.

  13. The numerical methods for the development of the mixture region in the vapor explosion simulations

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Y.; Ohashi, H.; Akiyama, M. [Univ. of Tokyo (Japan)

    1995-09-01

    An attempt to numerically simulate the process of the vapor explosion with a general multi-component and multi-dimension code is being challenged. Because of the rapid change of the flow field and extremely nonuniform distribution of the components in the system of the vapor explosion, the numerical divergence and diffusion are subject to occur easily. A dispersed component model and a multiregion scheme, by which these difficulties can be effectively overcome, were proposed. The simulations have been performed for the processes of the premixing and the fragmentation propagation in the vapor explosion.

  14. Numerical simulation of explosive magnetic cumulative generator EMG-720

    Energy Technology Data Exchange (ETDEWEB)

    Deryugin, Yu N; Zelenskij, D K; Kazakova, I F; Kargin, V I; Mironychev, P V; Pikar, A S; Popkov, N F; Ryaslov, E A; Ryzhatskova, E G [All-Russian Research Inst. of Experimental Physics, Sarov (Russian Federation)

    1997-12-31

    The paper discusses the methods and results of numerical simulations used in the development of a helical-coaxial explosive magnetic cumulative generator (EMG) with the stator up to 720 mm in diameter. In the process of designing, separate units were numerically modeled, as was the generator operation with a constant inductive-ohmic load. The 2-D processes of the armature acceleration by the explosion products were modeled as well as those of the formation of the sliding high-current contact between the armature and stator`s insulated turns. The problem of the armature integrity in the region of the detonation waves collision was numerically analyzed. 8 figs., 2 refs.

  15. Numerical simulation on the explosive boiling phenomena on the surface of molten metal

    International Nuclear Information System (INIS)

    Chen Deqi; Peng Cheng; Wang Qinghua; Pan Liangming

    2014-01-01

    In this paper, numerical simulation was carried out to investigate the explosive boiling phenomenon on high temperature surface also the influence of vapor growth rate during explosive boiling, vapor condensation in sub-cooled water and the subsequent effect on flowing and heat transfer. The simulation result indicates that the steam on the molten metal surface grows with very high speed, and it pushes away the sub-cooled water around and causes severe flowing. The steam clusters which block the sub-cooled water to rewet the molten metal surface are appearing at the same time. During the growth, lifting off as well as condensation of the steam clusters, the sub-cooled water around is strongly disturbed, and obvious vortexes appear. Conversely, the vortex will influence the steam cluster detachment and cub-cooled water rewetting the metal surface. This simulation visually displays the complex explosive boiling phenomena on the molten metal surface with high temperature. (authors)

  16. Simulation of changes in temperature and pressure fields during high speed projectiles forming by explosion

    Directory of Open Access Journals (Sweden)

    Marković Miloš D.

    2016-01-01

    Full Text Available The Research in this paper considered the temperatures fields as the consequently influenced effects appeared by plastic deformation, in the explosively forming process aimed to design Explosively Formed Projectiles (henceforth EFP. As the special payloads of the missiles, used projectiles are packaged as the metal liners, joined with explosive charges, to design explosive propulsion effect. Their final form and velocity during shaping depend on distributed temperatures in explosively driven plastic deformation process. Developed simulation model consider forming process without metal cover of explosive charge, in aim to discover liner’s dynamical correlations of effective plastic strains and temperatures in the unconstrained detonation environment made by payload construction. The temperature fields of the liner’s copper material are considered in time, as the consequence of strain/stress displacements driven by explosion environmental thermodynamically fields of pressures and temperatures. Achieved final velocities and mass loses as the expected EFP performances are estimated regarding their dynamical shaping and thermal gradients behavior vs. effective plastic strains. Performances and parameters are presented vs. process time, numerically simulated by the Autodyne software package. [Projekat Ministarstva nauke Republike Srbije, br. III-47029

  17. Dynamic Fracture Simulations of Explosively Loaded Cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Arthur, Carly W. [Univ. of California, Davis, CA (United States). Dept. of Civil and Environmental Engineering; Goto, D. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-11-30

    This report documents the modeling results of high explosive experiments investigating dynamic fracture of steel (AerMet® 100 alloy) cylinders. The experiments were conducted at Lawrence Livermore National Laboratory (LLNL) during 2007 to 2008 [10]. A principal objective of this study was to gain an understanding of dynamic material failure through the analysis of hydrodynamic computer code simulations. Two-dimensional and three-dimensional computational cylinder models were analyzed using the ALE3D multi-physics computer code.

  18. Numerical Simulation and Experimental Study on Formation of High Concentration of H2 Generated by Gas Explosion

    Directory of Open Access Journals (Sweden)

    Lei Baiwei

    2016-10-01

    Full Text Available In coal mine fire rescues, if the abnormal increase of gas concentration occurs, it is the primary thing to analyze the reasons and identify sources of the abnormal forming, which is also the basis of judge the combustion state of fire area and formulate proper fire reliefs. Nowadays, related researches have recognized the methane explosion as the source of high concentration of H2 formation, but there are few studies about the conditions and reaction mechanism of gas explosion generating high concentration of H2.Therefore, this paper uses the chemical kinetic calculation software, ChemKin, and the 20L spherical explosion experimental device to simulate the generating process and formation conditions of H2 in gas explosion. The experimental results show that: the decomposition of water vapor is the main base element reaction (R84 which leads to the generation of H2.The free radical H is the key factor to influence the formation of H2 generated from gas explosion. With the gradual increase of gas explosion concentration, the explosive reaction becomes more incomplete, and then the generating quantity of H2 increases gradually. Experimental results of 20L spherical explosion are consistent with the change trend about simulation results, which verifies the accuracy of simulation analysis. The results of explosion experiments show that when gas concentration is higher than 9%, the incomplete reaction of methane explosion increases which leads to the gradual increase of H2 formation.

  19. Explosive coalescence of magnetic islands and explosive particle acceleration

    International Nuclear Information System (INIS)

    Tajima, T.; Sakai, J.I.

    1985-07-01

    An explosive reconnection process associated with the nonlinear evolution of the coalescence instability is found through studies of the electromagnetic particle simulation and the magnetohydrodynamic particle simulation. The explosive coalescence is a process of magnetic collapse, in which we find the magnetic and electrostatic field energies and temperatures (ion temperature in the coalescing direction, in particular) explode toward the explosion time t 0 as (t 0 - t)/sup -8/3/, (t 0 - t) -4 , and (t 0 - t)/sup -8/3/, respectively for a canonical case. Single-peak, double-peak, and triple-peak structures of magnetic energy, temperature, and electrostatic energy, respectively, are observed on the simulation as overshoot amplitude oscillations and are theoretically explained. The heuristic model of Brunel and Tajima is extended to this explosive coalescence in order to extract the basic process. Since the explosive coalescence exhibits self-similarity, a temporal universality, we theoretically search for a self-similar solution to the two-fluid plasma equations

  20. Energetic lanthanide complexes: coordination chemistry and explosives applications

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  1. Simulations of Si-PIN photodiode based detectors for underground explosives enhanced by ammonium nitrate

    Science.gov (United States)

    Yücel, Mete; Bayrak, Ahmet; Yücel, Esra Barlas; Ozben, Cenap S.

    2018-02-01

    Massive Ammonium Nitrate (NH4-NO3) based explosives buried underground are commonly used in terror attacks. These explosives can be detected using neutron scattering method with some limitations. Simulations are very useful tools for designing a possible detection system for these kind of explosives. Geant4 simulations were used for generating neutrons at 14 MeV energy and tracking them through the scattering off the explosive embedded in soil. Si-PIN photodiodes were used as detector elements in the design for their low costs and simplicity for signal readout electronics. Various neutron-charge particle converters were applied on to the surface of the photodiodes to increase the detection efficiency. Si-PIN photodiodes coated with 6LiF provided the best result for a certain energy interval. Energy depositions in silicon detector from all secondary particles generated including photons were taken into account to generate a realistic background. Humidity of soil, one of the most important parameter for limiting the detection, was also studied.

  2. Monte Carlo simulation of explosive detection system based on a Deuterium-Deuterium (D-D) neutron generator.

    Science.gov (United States)

    Bergaoui, K; Reguigui, N; Gary, C K; Brown, C; Cremer, J T; Vainionpaa, J H; Piestrup, M A

    2014-12-01

    An explosive detection system based on a Deuterium-Deuterium (D-D) neutron generator has been simulated using the Monte Carlo N-Particle Transport Code (MCNP5). Nuclear-based explosive detection methods can detect explosives by identifying their elemental components, especially nitrogen. Thermal neutron capture reactions have been used for detecting prompt gamma emission (10.82MeV) following radiative neutron capture by (14)N nuclei. The explosive detection system was built based on a fully high-voltage-shielded, axial D-D neutron generator with a radio frequency (RF) driven ion source and nominal yield of about 10(10) fast neutrons per second (E=2.5MeV). Polyethylene and paraffin were used as moderators with borated polyethylene and lead as neutron and gamma ray shielding, respectively. The shape and the thickness of the moderators and shields are optimized to produce the highest thermal neutron flux at the position of the explosive and the minimum total dose at the outer surfaces of the explosive detection system walls. In addition, simulation of the response functions of NaI, BGO, and LaBr3-based γ-ray detectors to different explosives is described. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Penetration Evaluation of Explosively Formed Projectiles Through Air and Water Using Insensitive Munition: Simulative and Experimental Studies

    Directory of Open Access Journals (Sweden)

    M. Ahmed

    2016-02-01

    Full Text Available The process of formation, flying, penetration of explosively-formed projectiles (EFP and the effect of water on performance of the charge for underwater applications is simulated by Ansysis Autodyn 2D-Hydro code. The main objective of an explosively formed projectile designed for underwater applications is to disintegrate the target at longer standoff distances. In this paper we have simulated the explosively formed projectile from OFHC-Copper liner for 1200 conical angle. The Affect of water on the penetration of EFP is determined by simulations from Ansysis Autodyn 2-D Hydrocode and by varying depth of water from 1CD-5CD. The depth of penetration against steel target is measured experimentally. Flash X-Ray Radiography (FXR is used to capture EFP jet formation and its penetration against target is measured by depth of penetration experiments. Simulation results are compared with experimental results. The difference in simulated and experimental results for depth of penetration is about 7 mm, which lies within favorable range of error. The jet formation captured from FXR is quite clear and jet velocity determined from Flash X-ray radiography is the same as the ones obtained by using other high explosives. Therefore, it is indicated that Insensitive Munition (8701 can be utilized instead of Polymer Bonded Explosives (PBX for air and underwater environments with great reliability and without any hazard.

  4. Experimental simulation of microinteractions in large scale explosions

    Energy Technology Data Exchange (ETDEWEB)

    Chen, X.; Luo, R.; Yuen, W.W.; Theofanous, T.G. [California Univ., Santa Barbara, CA (United States). Center for Risk Studies and Safety

    1998-01-01

    This paper presents data and analysis of recent experiments conducted in the SIGMA-2000 facility to simulate microinteractions in large scale explosions. Specifically, the fragmentation behavior of a high temperature molten steel drop under high pressure (beyond critical) conditions are investigated. The current data demonstrate, for the first time, the effect of high pressure in suppressing the thermal effect of fragmentation under supercritical conditions. The results support the microinteractions idea, and the ESPROSE.m prediction of fragmentation rate. (author)

  5. Quantum chemistry simulation on quantum computers: theories and experiments.

    Science.gov (United States)

    Lu, Dawei; Xu, Boruo; Xu, Nanyang; Li, Zhaokai; Chen, Hongwei; Peng, Xinhua; Xu, Ruixue; Du, Jiangfeng

    2012-07-14

    It has been claimed that quantum computers can mimic quantum systems efficiently in the polynomial scale. Traditionally, those simulations are carried out numerically on classical computers, which are inevitably confronted with the exponential growth of required resources, with the increasing size of quantum systems. Quantum computers avoid this problem, and thus provide a possible solution for large quantum systems. In this paper, we first discuss the ideas of quantum simulation, the background of quantum simulators, their categories, and the development in both theories and experiments. We then present a brief introduction to quantum chemistry evaluated via classical computers followed by typical procedures of quantum simulation towards quantum chemistry. Reviewed are not only theoretical proposals but also proof-of-principle experimental implementations, via a small quantum computer, which include the evaluation of the static molecular eigenenergy and the simulation of chemical reaction dynamics. Although the experimental development is still behind the theory, we give prospects and suggestions for future experiments. We anticipate that in the near future quantum simulation will become a powerful tool for quantum chemistry over classical computations.

  6. Design and validation of inert homemade explosive simulants for ground penetrating radar

    Science.gov (United States)

    VanderGaast, Brian W.; McFee, John E.; Russell, Kevin L.; Faust, Anthony A.

    2015-05-01

    The Canadian Armed Forces (CAF) identified a requirement for inert simulants to act as improvised, or homemade, explosives (IEs) when training on, or evaluating, ground penetrating radar (GPR) systems commonly used in the detection of buried landmines and improvised explosive devices (IEDs). In response, Defence R and D Canada (DRDC) initiated a project to develop IE simulant formulations using commonly available inert materials. These simulants are intended to approximate the expected GPR response of common ammonium nitrate-based IEs, in particular ammonium nitrate/fuel oil (ANFO) and ammonium nitrate/aluminum (ANAl). The complex permittivity over the range of electromagnetic frequencies relevant to standard GPR systems was measured for bulk quantities of these three IEs that had been fabricated at DRDC Suffield Research Centre. Following these measurements, published literature was examined to find benign materials with both a similar complex permittivity, as well as other physical properties deemed desirable - such as low-toxicity, thermal stability, and commercial availability - in order to select candidates for subsequent simulant formulation. Suitable simulant formulations were identified for ANFO, with resulting complex permittivities measured to be within acceptable limits of target values. These IE formulations will now undergo end-user trials with CAF operators in order to confirm their utility. Investigations into ANAl simulants continues. This progress report outlines the development program, simulant design, and current validation results.

  7. Simulation Study of Near-Surface Coupling of Nuclear Devices vs. Equivalent High-Explosive Charges

    Energy Technology Data Exchange (ETDEWEB)

    Fournier, Kevin B [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Walton, Otis R [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Benjamin, Russ [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dunlop, William H [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-09-29

    A computational study was performed to examine the differences in near-surface ground-waves and air-blast waves generated by high-explosive energy sources and those generated by much higher energy - density low - yield nuclear sources. The study examined the effect of explosive-source emplacement (i.e., height-of-burst, HOB, or depth-of-burial, DOB) over a range from depths of -35m to heights of 20m, for explosions with an explosive yield of 1-kt . The chemical explosive was modeled by a JWL equation-of-state model for a ~14m diameter sphere of ANFO (~1,200,000kg – 1 k t equivalent yield ), and the high-energy-density source was modeled as a one tonne (1000 kg) plasma of ‘Iron-gas’ (utilizing LLNL’s tabular equation-of-state database, LEOS) in a 2m diameter sphere, with a total internal-energy content equivalent to 1 k t . A consistent equivalent-yield coupling-factor approach was developed to compare the behavior of the two sources. The results indicate that the equivalent-yield coupling-factor for air-blasts from 1 k t ANFO explosions varies monotonically and continuously from a nearly perfec t reflected wave off of the ground surface for a HOB ≈ 20m, to a coupling factor of nearly zero at DOB ≈ -25m. The nuclear air - blast coupling curve, on the other hand, remained nearly equal to a perfectly reflected wave all the way down to HOB’s very near zero, and then quickly dropped to a value near zero for explosions with a DOB ≈ -10m. The near - surface ground - wave traveling horizontally out from the explosive source region to distances of 100’s of meters exhibited equivalent - yield coupling - factors t hat varied nearly linearly with HOB/DOB for the simulated ANFO explosive source, going from a value near zero at HOB ≈ 5m to nearly one at DOB ≈ -25m. The nuclear-source generated near-surface ground wave coupling-factor remained near zero for almost all HOB’s greater than zero, and then appeared to vary nearly - linearly with depth

  8. PhET Interactive Simulations: Transformative Tools for Teaching Chemistry

    Science.gov (United States)

    Moore, Emily B.; Chamberlain, Julia M.; Parson, Robert; Perkins, Katherine K.

    2014-01-01

    Developing fluency across symbolic-, macroscopic-, and particulate-level representations is central to learning chemistry. Within the chemistry education community, animations and simulations that support multi-representational fluency are considered critical. With advances in the accessibility and sophistication of technology,…

  9. Experimental simulation of lightning, interacting explosions and astrophysical jets with pulsed lasers

    International Nuclear Information System (INIS)

    Villagran-Muniz, M; Sobral, H; Navarro-Gonzalez, R; Velazquez, P F; Raga, A C

    2003-01-01

    Tabletop laboratory experiments have been used to simulate natural lightning, interacting explosions and astrophysical jets. When a high-energy laser pulse is focused in air, a laser-induced plasma (LIP) is produced, that generates a shock wave and an adiabatic expansion of the gas. In our work we have used LIPs in order to simulate lightning, for the study of chemical reactions relevant to atmospheric science. Several diagnostics have been applied to our LIPs, such as deflectometry, shadowgraphy and interferometry, which yield full spatial information of the process (electron density and temperature, the position of the shock wave fronts and the expansion of the hot gas), with a time resolution that ranges from nanoseconds to milliseconds. A new diagnostic alternative was implemented for shadowgraphy, which uses either continuous lasers or conventional light sources. The experimental results have been reproduced by hydrodynamic codes that we have developed. With astrophysical applications in mind, we have simulated and diagnosed the interaction of two explosions, with the aforementioned techniques. For this purpose, two LIPs are synchronized and diagnosed spatially and temporarily. Also, by producing the LIP in a glass sphere with a nozzle that ejects a shock wave and hot gas, we are able to simulate astrophysical jets. With such experiments, astrophysical models developed by us have been validated, showing excellent agreement between experiments and numerical simulations

  10. Characterization Of High Explosives Detonations Via Laser-Induced Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Villa-Aleman, E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-08

    One objective of the Department of Energy’s National Security Administration is to develop technologies that can help the United States government to detect foreign nuclear weapons development activities. The realm of high explosive (HE) experiments is one of the key areas to assess the nuclear ambitions of a country. SRNL has participated in the collection of particulates from HE experiments and characterized the material with the purpose to correlate particulate matter with HE. Since these field campaigns are expensive, on-demand simulated laboratory-scale explosion experiments are needed to further our knowledge of the chemistry and particle formation in the process. Our goal is to develop an experimental test bed in the laboratory to test measurement concepts and correlate particle formation processes with the observables from the detonation fireball. The final objective is to use this knowledge to tailor our experimental setups in future field campaigns. The test bed uses pulsed laser-induced plasmas to simulate micro-explosions, with the intent to study the temporal behavior of the fireball observed in field tests. During FY15, a plan was prepared and executed which assembled two laser ablation systems, procured materials for study, and tested a Step-Scan Fourier Transform Infrared Spectrometer (SS-FTIR). Designs for a shadowgraph system for shock wave analysis, design for a micro-particulate collector from ablated pulse were accomplished. A novel spectroscopic system was conceived and a prototype system built for acquisition of spectral/temporal characterization of a high speed event such as from a high explosive detonation. Experiments and analyses will continue into FY16.

  11. Mathematical modelling of the decomposition of explosives

    International Nuclear Information System (INIS)

    Smirnov, Lev P

    2010-01-01

    Studies on mathematical modelling of the molecular and supramolecular structures of explosives and the elementary steps and overall processes of their decomposition are analyzed. Investigations on the modelling of combustion and detonation taking into account the decomposition of explosives are also considered. It is shown that solution of problems related to the decomposition kinetics of explosives requires the use of a complex strategy based on the methods and concepts of chemical physics, solid state physics and theoretical chemistry instead of empirical approach.

  12. Accelerating Our Understanding of Supernova Explosion Mechanism via Simulations and Visualizations with GenASiS

    Energy Technology Data Exchange (ETDEWEB)

    Budiardja, R. D. [University of Tennessee, Knoxville (UTK); Cardall, Christian Y [ORNL; Endeve, Eirik [ORNL

    2015-01-01

    Core-collapse supernovae are among the most powerful explosions in the Universe, releasing about 1053 erg of energy on timescales of a few tens of seconds. These explosion events are also responsible for the production and dissemination of most of the heavy elements, making life as we know it possible. Yet exactly how they work is still unresolved. One reason for this is the sheer complexity and cost of a self-consistent, multi-physics, and multi-dimensional core-collapse supernova simulation, which is impractical, and often impossible, even on the largest supercomputers we have available today. To advance our understanding we instead must often use simplified models, teasing out the most important ingredients for successful explosions, while helping us to interpret results from higher fidelity multi-physics models. In this paper we investigate the role of instabilities in the core-collapse supernova environment. We present here simulation and visualization results produced by our code GenASiS.

  13. Steam explosion triggering phenomena: stainless steel and corium-E simulants studied with a floodable arc melting apparatus

    International Nuclear Information System (INIS)

    Nelson, L.S.; Buxton, L.D.

    1978-05-01

    Laboratory-scale experiments on the thermal interaction of light water reactor core materials with water have been performed. Samples (10--35 g) of Type 304 stainless steel and Corium-E simulants were each flooded with approximately 1.5 litres of water to determine whether steam explosions would occur naturally. Many of the experiments also employed artificially induced pressure transients in an attempt to initiate steam explosions. Vigorous interactions were not observed when the triggering pulse was not applied, and for stainless steel the triggering pulse initiated only coarse fragmentation. Two-stage, pressure-producing interactions were triggered for an ''oxidic'' Corium-E simulant. An impulse-initiated gas release theory has been simulated to explain the initial sample fragmentation. Although the delayed second stage of the event is not fully understood, it does not appear to be readily explained with classical vapor explosion theory. Rather, some form of metastability of the melt seems to be involved

  14. Explosive hazards in polyaniline chemistry

    Czech Academy of Sciences Publication Activity Database

    Stejskal, Jaroslav; Bober, Patrycja; Trchová, Miroslava; Prokeš, J.

    2017-01-01

    Roč. 71, č. 2 (2017), s. 387-392 ISSN 0366-6352 R&D Projects: GA ČR(CZ) GA13-00270S Institutional support: RVO:61389013 Keywords : polyaniline * oxidation of aniline * safety hazards Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 1.258, year: 2016

  15. The Numerical Simulation of the Shock Wave of Coal Gas Explosions in Gas Pipe*

    Science.gov (United States)

    Chen, Zhenxing; Hou, Kepeng; Chen, Longwei

    2018-03-01

    For the problem of large deformation and vortex, the method of Euler and Lagrange has both advantage and disadvantage. In this paper we adopt special fuzzy interface method(volume of fluid). Gas satisfies the conditions of conservation equations of mass, momentum, and energy. Based on explosion and three-dimension fluid dynamics theory, using unsteady, compressible, inviscid hydrodynamic equations and state equations, this paper considers pressure gradient’s effects to velocity, mass and energy in Lagrange steps by the finite difference method. To minimize transport errors of material, energy and volume in Finite Difference mesh, it also considers material transport in Euler steps. Programmed with Fortran PowerStation 4.0 and visualized with the software designed independently, we design the numerical simulation of gas explosion with specific pipeline structure, check the key points of the pressure change in the flow field, reproduce the gas explosion in pipeline of shock wave propagation, from the initial development, flame and accelerate the process of shock wave. This offers beneficial reference and experience to coal gas explosion accidents or safety precautions.

  16. Chemistry laboratory safety manual available

    Science.gov (United States)

    Elsbrock, R. G.

    1968-01-01

    Chemistry laboratory safety manual outlines safe practices for handling hazardous chemicals and chemistry laboratory equipment. Included are discussions of chemical hazards relating to fire, health, explosion, safety equipment and procedures for certain laboratory techniques and manipulations involving glassware, vacuum equipment, acids, bases, and volatile solvents.

  17. Simulated nuclear optical signatures using explosive light sources (ELS)

    International Nuclear Information System (INIS)

    Glaser, R.F.

    1979-05-01

    Four Explosive Light Source (aluminium powder and oxygen) tests were conducted on the test range at Sandia Laboratories in Albuquerque (SLA) from 28 February through 7 March 1978. Although several types of measuring devices were used, the report documents only the optical time histories measured by the bhangmeters and the NBDS, and explains the conclusions reached. In general, the four shots made it possible to gather clear-air optical transmission data, determine the suitability of ELS to simulate the optical effects of a nuclear burst, and provide experience for the larger scale ELS tests to be conducted at Fort Ord, CA in April

  18. Simulated nuclear optical signatures using explosive light sources (ELS)

    Energy Technology Data Exchange (ETDEWEB)

    Glaser, R.F.

    1979-05-01

    Four Explosive Light Source (aluminium powder and oxygen) tests were conducted on the test range at Sandia Laboratories in Albuquerque (SLA) from 28 February through 7 March 1978. Although several types of measuring devices were used, the report documents only the optical time histories measured by the bhangmeters and the NBDS, and explains the conclusions reached. In general, the four shots made it possible to gather clear-air optical transmission data, determine the suitability of ELS to simulate the optical effects of a nuclear burst, and provide experience for the larger scale ELS tests to be conducted at Fort Ord, CA in April.

  19. Finite-difference numerical simulations of underground explosion cavity decoupling

    Science.gov (United States)

    Aldridge, D. F.; Preston, L. A.; Jensen, R. P.

    2012-12-01

    Earth models containing a significant portion of ideal fluid (e.g., air and/or water) are of increasing interest in seismic wave propagation simulations. Examples include a marine model with a thick water layer, and a land model with air overlying a rugged topographic surface. The atmospheric infrasound community is currently interested in coupled seismic-acoustic propagation of low-frequency signals over long ranges (~tens to ~hundreds of kilometers). Also, accurate and efficient numerical treatment of models containing underground air-filled voids (caves, caverns, tunnels, subterranean man-made facilities) is essential. In support of the Source Physics Experiment (SPE) conducted at the Nevada National Security Site (NNSS), we are developing a numerical algorithm for simulating coupled seismic and acoustic wave propagation in mixed solid/fluid media. Solution methodology involves explicit, time-domain, finite-differencing of the elastodynamic velocity-stress partial differential system on a three-dimensional staggered spatial grid. Conditional logic is used to avoid shear stress updating within the fluid zones; this approach leads to computational efficiency gains for models containing a significant proportion of ideal fluid. Numerical stability and accuracy are maintained at air/rock interfaces (where the contrast in mass density is on the order of 1 to 2000) via a finite-difference operator "order switching" formalism. The fourth-order spatial FD operator used throughout the bulk of the earth model is reduced to second-order in the immediate vicinity of a high-contrast interface. Current modeling efforts are oriented toward quantifying the amount of atmospheric infrasound energy generated by various underground seismic sources (explosions and earthquakes). Source depth and orientation, and surface topography play obvious roles. The cavity decoupling problem, where an explosion is detonated within an air-filled void, is of special interest. A point explosion

  20. Computational Flame Diagnostics for Direct Numerical Simulations with Detailed Chemistry of Transportation Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Tianfeng [Univ. of Connecticut, Storrs, CT (United States)

    2017-02-16

    The goal of the proposed research is to create computational flame diagnostics (CFLD) that are rigorous numerical algorithms for systematic detection of critical flame features, such as ignition, extinction, and premixed and non-premixed flamelets, and to understand the underlying physicochemical processes controlling limit flame phenomena, flame stabilization, turbulence-chemistry interactions and pollutant emissions etc. The goal has been accomplished through an integrated effort on mechanism reduction, direct numerical simulations (DNS) of flames at engine conditions and a variety of turbulent flames with transport fuels, computational diagnostics, turbulence modeling, and DNS data mining and data reduction. The computational diagnostics are primarily based on the chemical explosive mode analysis (CEMA) and a recently developed bifurcation analysis using datasets from first-principle simulations of 0-D reactors, 1-D laminar flames, and 2-D and 3-D DNS (collaboration with J.H. Chen and S. Som at Argonne, and C.S. Yoo at UNIST). Non-stiff reduced mechanisms for transportation fuels amenable for 3-D DNS are developed through graph-based methods and timescale analysis. The flame structures, stabilization mechanisms, local ignition and extinction etc., and the rate controlling chemical processes are unambiguously identified through CFLD. CEMA is further employed to segment complex turbulent flames based on the critical flame features, such as premixed reaction fronts, and to enable zone-adaptive turbulent combustion modeling.

  1. Simulation of the chemical environment of a nuclear explosion with exploding wires

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Walter; Block, Oliver U.J. [Nuclear Engineering, Kansas State University, Manhattan, KS (United States)

    1970-05-15

    The chemical processes in an expanding underground cavity resulting from a nuclear explosion cannot be predicted or controlled as well as such physical characteristics as crater size, magnitude of the outgoing shock wave, or the extent of rock fracturing. However in most underground nuclear explosions it would be desirable to control the chemical and/or physical form and amount of radioactive fallout venting from the explosion. The high temperatures and corresponding high energy densities produced by exploding wires are sufficient to produce in the wire and material immediately surrounding it the temperature (a few thousand degrees) required to simulate the chemical environment of a nuclear explosion in the time interval just preceding the venting of the cavity. The economics and the size of exploding wire apparatus make this type of experiment readily applicable to laboratory study. Design of exploding wire circuits to obtain particular temperatures or energy densities can be completed using several different combinations of circuit and wire conditions. Since the circuit parameters, including charging voltage, capacitor bank capacitance and circuit inductance primarily determine the cost of the necessary laboratory equipment, these parameters should be selected by theoretical expressions while also considering economic factors. Wire parameters are then experimentally determined to produce the most energetic explosions with the selected circuit parameters. A theoretical method applicable to designing exploding wire circuits to produce the desired high temperatures and energy densities in the wire and surrounding sample material has been obtained. The method assumes that a thermal spike of energy is deposited in a low conductivity material (typical of the earth's crust) surrounding the wire. From the assumed temperature distribution in the surrounding sample material the energy which must be deposited in the thermal spike to produce the desired temperature and

  2. Modeling and simulation of explosion effectiveness as a function of blast and crowd characteristics

    Science.gov (United States)

    Usmani, Zeeshan-Ul-Hassan

    Suicide bombing has become one of the most lethal and favorite modus operandi of terrorist organizations around the world. On average, there is a suicide bombing attack every six days somewhere in the world. While various attempts have been made to assess the impact of explosions on structures and military personnel, little has been done on modeling the impact of a blast wave on a crowd in civilian settings. The assessment of an explosion's effect on a crowd can lead to better management of disasters, triage of patients, locating blast victims under the debris, development of protective gear, and safe distance recommendations to reduce the casualties. The overall goal of this work is to predict the magnitude of injuries and lethality on humans from a blast-wave with various explosive and crowd characteristics, and to compare, contrast, and analyze the performance of explosive and injury models against the real-life data of suicide bombing incidents. This thesis introduces BlastSim---a physics based stationary multi-agent simulation platform to model and simulate a suicide bombing event. The agents are constrained by the physical characteristics and mechanics of the blast wave. The BlastSim is programmed to test, analyze, and validate the results of different model combinations under various conditions with different sets of parameters, such as the crowd and explosive characteristics, blockage and human shields, fragmentation and the bomber's position, in 2-dimensional and 3-dimensional environments. The suicide bombing event can be re-created for forensic analysis. The proposed model combinations show a significant performance---the Harold Brode explosive model with Catherine Lee injury model using the blockage stands out consistently to be the best with an overall cumulative accuracy of 87.6%. When comparing against actual data, overall, prediction accuracy can be increased by 71% using this model combination. The J. Clutter with Reflection explosive model using

  3. Investigating the Effectiveness of Computer Simulations for Chemistry Learning

    Science.gov (United States)

    Plass, Jan L.; Milne, Catherine; Homer, Bruce D.; Schwartz, Ruth N.; Hayward, Elizabeth O.; Jordan, Trace; Verkuilen, Jay; Ng, Florrie; Wang, Yan; Barrientos, Juan

    2012-01-01

    Are well-designed computer simulations an effective tool to support student understanding of complex concepts in chemistry when integrated into high school science classrooms? We investigated scaling up the use of a sequence of simulations of kinetic molecular theory and associated topics of diffusion, gas laws, and phase change, which we designed…

  4. Titan's organic chemistry: Results of simulation experiments

    Science.gov (United States)

    Sagan, Carl; Thompson, W. Reid; Khare, Bishun N.

    1992-01-01

    Recent low pressure continuous low plasma discharge simulations of the auroral electron driven organic chemistry in Titan's mesosphere are reviewed. These simulations yielded results in good accord with Voyager observations of gas phase organic species. Optical constants of the brownish solid tholins produced in similar experiments are in good accord with Voyager observations of the Titan haze. Titan tholins are rich in prebiotic organic constituents; the Huygens entry probe may shed light on some of the processes that led to the origin of life on Earth.

  5. Using Computer Simulations in Chemistry Problem Solving

    Science.gov (United States)

    Avramiotis, Spyridon; Tsaparlis, Georgios

    2013-01-01

    This study is concerned with the effects of computer simulations of two novel chemistry problems on the problem solving ability of students. A control-experimental group, equalized by pair groups (n[subscript Exp] = n[subscript Ctrl] = 78), research design was used. The students had no previous experience of chemical practical work. Student…

  6. Numerical Simulation of Explosive Forming Using Detonating Fuse

    OpenAIRE

    H Iyama; Y Higa; M Nishi; S Itoh

    2017-01-01

    The explosive forming is a characteristic method. An underwater shock wave is generated by underwater explosion of an explosive. A metal plate is affected high strain rate by the shock loading and is formed along a metal die. Although this method has the advantage of mirroring the shape of the die, a free forming was used in this paper. An expensive metal die is not necessary for this free forming. It is possible that a metal plate is formed with simple supporting parts. However, the forming ...

  7. Simulation of TROI steam explosion behaviour using the COMETA code

    International Nuclear Information System (INIS)

    Arun Kumar Nayak; Hyun Sun Park; Bal Raj Sehgal; Alessandro Annunziato

    2005-01-01

    Full text of publication follows: During a severe accident in a nuclear reactor, the core can melt and the molten corium while interacting with water may cause an energetic fuel coolant interaction which is known as steam explosion. Such phenomena can occur inside the reactor vessel during flooding of a degraded core or when molten corium falls into the lower head filled with water. Similar phenomena may occur outside the reactor vessel when molten corium is ejected into a flooded reactor cavity or into the flooded containment after the vessel failure. The interaction of molten corium with water is one of the most complex thermal hydraulic and chemical phenomena. Recently in the TROI test series carried out at KAERI (Korean Atomic Energy Research Institute) in Korea, steam explosions were observed. In those tests, the UO 2 /ZrO 2 compositions were close to that of prototypic case. In this paper, we have numerically simulated the melt coolant interaction of TROI tests using the computer code, COMETA (Core MElt Thermalhydraulic Analysis) developed by JRC (Joint Research Center), at Ispra in Italy. The COMETA code was primarily developed to analyse, with sufficient detail, both the thermal-hydraulics and the fuel fragmentation phenomena during the melt quenching tests as conducted in the FARO facility. The code solves the conservation equations of mass, momentum and energy for the fluid using a conventional two-fluid model. Fuel fragmentation model considers the molten jet, its break up in drops and accumulation as fused-debris on the bottom. An explicit coupling between the thermal hydraulics and fuel fragmentation for the energy transfer is considered. The code has been extensively validated in the past for melt quenching in a series of experiments in the FARO facility. In this work, we first simulated the pre-mix and triggering phases of the TROI-13 tests for which the test data were available. The melt jet trajectory, void fraction and pressure profile were

  8. Toward Improved Fidelity of Thermal Explosion Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, A L; Becker, R; Howard, W M; Wemhoff, A

    2009-07-17

    We will present results of an effort to improve the thermal/chemical/mechanical modeling of HMX based explosive like LX04 and LX10 for thermal cook-off. The original HMX model and analysis scheme were developed by Yoh et.al. for use in the ALE3D modeling framework. The current results were built to remedy the deficiencies of that original model. We concentrated our efforts in four areas. The first area was addition of porosity to the chemical material model framework in ALE3D that is used to model the HMX explosive formulation. This is needed to handle the roughly 2% porosity in solid explosives. The second area was the improvement of the HMX reaction network, which included the inclusion of a reactive phase change model base on work by Henson et.al. The third area required adding early decomposition gas species to the CHEETAH material database to develop more accurate equations of state for gaseous intermediates and products. Finally, it was necessary to improve the implicit mechanics module in ALE3D to more naturally handle the long time scales associated with thermal cook-off. The application of the resulting framework to the analysis of the Scaled Thermal Explosion (STEX) experiments will be discussed.

  9. Application of light-initiated explosive for simulating x-ray blowoff impulse effects on a full scale reentry vehicle

    International Nuclear Information System (INIS)

    Benham, R.A.; Mathews, F.H.; Higgins, P.B.

    1976-01-01

    Laboratory nuclear effects testing allows the study of reentry vehicle response to simulated exoatmospheric x-ray encounters. Light-initiated explosive produces the nearly simultaneous impulse loading of a structure by using a spray painted coating of explosive which is detonated by an intense flash of light. A lateral impulse test on a full scale reentry vehicle is described which demonstrates that the light-initiated explosive technique can be extended to the lateral loading of very large systems involving load discontinuities. This experiment required the development of a diagnostic method for verifying the applied impulse, and development of a large light source for simultaneously initiating the explosive over the surface of the vehicle. Acceptable comparison between measured strain response and code predictions is obtained. The structural capability and internal response of a vehicle subjected to an x-ray environment was determined from a light-initiated explosive test

  10. Non-equilibrium chemistry and cooling in simulations of galaxy formation

    NARCIS (Netherlands)

    Richings, Alexander James

    2015-01-01

    In this thesis we used numerical simulations to explore the role that chemistry plays in galaxy formation. Simulations of galaxies often assume chemical equilibrium, where the chemical reactions between ions and molecules have reached a steady state. However, this assumption may not be valid if the

  11. Radiation chemistry in the Jovian stratosphere - Laboratory simulations

    Science.gov (United States)

    Mcdonald, Gene D.; Thompson, W. R.; Sagan, Carl

    1992-01-01

    The results of the present low-pressure/continuous-flow laboratory simulations of H2/He/CH4/NH3 atmospheres' plasma-induced chemistry indicate radiation yields of both hydrocarbon and N2-containing organic compounds which increase with decreasing pressure. On the basis of these findings, upper limits of 1 million-1 billion molecules/sq cm/sec are established for production rates of major auroral-chemistry species in the Jovian stratosphere. It is noted that auroral processes may account for 10-100 percent of the total abundances of most of the observed polar-region organic species.

  12. Simulation of Water Chemistry using and Geochemistry Code, PHREEQE

    Energy Technology Data Exchange (ETDEWEB)

    Chi, J.H. [Korea Electric Power Research Institute, Taejeon (Korea)

    2001-07-01

    This report introduces principles and procedures of simulation for water chemistry using a geochemistry code, PHREEQE. As and example of the application of this code, we described the simulation procedure for titration of an aquatic sample with strong acid to investigate the state of Carbonates in aquatic solution. Major contents of this report are as follows; Concepts and principles of PHREEQE, Kinds of chemical reactions which may be properly simulated by PHREEQE, The definition and meaning of each input data, An example of simulation using PHREEQE. (author). 2 figs., 1 tab.

  13. Premixing and steam explosion phenomena in the tests with stratified melt-coolant configuration and binary oxidic melt simulant materials

    Energy Technology Data Exchange (ETDEWEB)

    Kudinov, Pavel, E-mail: pavel@safety.sci.kth.se; Grishchenko, Dmitry, E-mail: dmitry@safety.sci.kth.se; Konovalenko, Alexander, E-mail: kono@kth.se; Karbojian, Aram, E-mail: karbojan@kth.se

    2017-04-01

    Highlights: • Steam explosion in stratified melt-coolant configuration is studied experimentally. • Different binary oxidic melt simulant materials were used. • Five spontaneous steam explosions were observed. • Instability of melt-coolant interface and formation of premixing layer was observed. • Explosion strength is influenced by melt superheat and water subcooling. - Abstract: Steam explosion phenomena in stratified melt-coolant configuration are considered in this paper. Liquid corium layer covered by water on top can be formed in severe accident scenarios with (i) vessel failure and release of corium melt into a relatively shallow water pool; (ii) with top flooding of corium melt layer. In previous assessments of potential energetics in stratified melt-coolant configuration, it was assumed that melt and coolant are separated by a stable vapor film and there is no premixing prior to the shock wave propagation. This assumption was instrumental for concluding that the amount of energy that can be released in such configuration is not of safety importance. However, several recent experiments carried out in Pouring and Under-water Liquid Melt Spreading (PULiMS) facility with up to 78 kg of binary oxidic corium simulants mixtures have resulted in spontaneous explosions with relatively high conversion ratios (order of one percent). The instability of the melt-coolant interface, melt splashes and formation of premixing layer were observed in the tests. In this work, we present results of experiments carried out more recently in steam explosion in stratified melt-coolant configuration (SES) facility in order to shed some light on the premixing phenomena and assess the influence of the test conditions on the steam explosion energetics.

  14. EVENT, Explosive Transients in Flow Networks

    International Nuclear Information System (INIS)

    Andrae, R.W.; Tang, P.K.; Bolstad, J.W.; Gregory, W.S.

    1985-01-01

    1 - Description of problem or function: A major concern of the chemical, nuclear, and mining industries is the occurrence of an explosion in one part of a facility and subsequent transmission of explosive effects through the ventilation system. An explosive event can cause performance degradation of the ventilation system or even structural failures. A more serious consequence is the release of hazardous materials to the environment if vital protective devices such as air filters, are damaged. EVENT was developed to investigate the effects of explosive transients through fluid-flow networks. Using the principles of fluid mechanics and thermodynamics, governing equations for the conservation of mass, energy, and momentum are formulated. These equations are applied to the complete network subdivided into two general components: nodes and branches. The nodes represent boundaries and internal junctions where the conservation of mass and energy applies. The branches can be ducts, valves, blowers, or filters. Since in EVENT the effect of the explosion, not the characteristics of the explosion itself, is of interest, the transient is simulated in the simplest possible way. A rapid addition of mass and energy to the system at certain locations is used. This representation is adequate for all of the network except the region where the explosion actually occurs. EVENT84 is a modification of EVENT which includes a new explosion chamber model subroutine based on the NOL BLAST program developed at the Naval Ordnance Laboratory, Silver Spring, Maryland. This subroutine calculates the confined explosion near-field parameters and supplies the time functions of energy and mass injection. Solid-phase or TNT-equivalent explosions (which simulate 'point source' explosions in nuclear facilities) as well as explosions in gas-air mixtures can be simulated. The four types of explosions EVENT84 simulates are TNT, hydrogen in air, acetylene in air, and tributyl phosphate (TBP or 'red oil

  15. Statistical estimation of loads from gas explosions

    Energy Technology Data Exchange (ETDEWEB)

    Hoeiset, Stian

    1998-12-31

    In the design of structures in the offshore and process industries, the possibility of a gas explosion must always be considered. The main uncertainties in computerized simulation of gas explosions are the assumptions of the gas cloud, the location of the ignition point and the properties of the simulator itself. This thesis quantifies the levels of these uncertainties by performing a large number of simulations on three offshore modules and one onshore plant. It is found that (1) there is an approximate linear relation between pressure and gas volume, (2) it may be possible to find a linear relation between pressure and impulse, (3) there is an inverse relation between pressure and duration, (4) the response of offshore structures exposed to gas explosions are rarely in the impulsive regime, (5) loading rates vary widely in magnitude, (6) an assumption of a triangular explosion pulse is often correct, (7) louvres increase pressure, impulse and duration of an explosion. The effect of ignition point location is studied in detail. It is possible to derive an ignition point uncertainty load factor that shows predictable behaviour by generalizing the non-parametric properties of the explosion pressure. A model for taking into account the uncertainties regarding gas volume, ignition point location and simulator imperfectness is proposed. The model is intended to produce a characteristic load for structural design. 68 refs., 51 figs., 36 tabs.

  16. Chemistry of high-energy materials

    Energy Technology Data Exchange (ETDEWEB)

    Klapoetke, Thomas M. [Ludwig-Maximilians-Univ., Muenchen (Germany). Dept. of Chemistry; Maryland Univ., College Park, MD (US). Center of Energetic Concepts Development (CECD)

    2011-07-01

    The graduate-level textbook Chemistry of High-Energy Materials provides an introduction to and an overview of primary and secondary (high) explosives as well as propellant charges, rocket propellants and pyrotechnics. After a brief historical overview, the main classes of energetic materials are discussed systematically. Thermodynamic aspects, as far as relevant to energetic materials, are discussed, as well as modern computational approaches to predict performance and sensitivity parameters. The most important performance criteria such as detonation velocity, detonation pressure and heat of explosion, as well as the relevant sensitivity parameters suc as impact and friction sensitivity and electrostatic discharge sensitivity are explored in detail. Modern aspects of chemical synthesis including lead-free primary explosives and high-nitrogen compounds are also included in this book together with a discussion of high-energy materials for future defense needs. The most important goal of this book, based on a lecture course which has now been held at LMU Munich for over 12 years, is to increase knowledge and know-how in the synthesis and safe handling of high-energy materials. Society needs now as much as ever advanced explosives, propellant charges, rocket propellants and pyrotechnics to meet the demands in defense and engineering. This book is first and foremost aimed at advanced students in chemistry, engineering and materials sciences. However, it is also intended to provide a good introduction to the chemistry of energetic materials and chemical defense technology for scientists in the defense industry and government-run defense organizations. (orig.)

  17. Five-component propagation model for steam explosion analysis

    International Nuclear Information System (INIS)

    Yang, Y.; Moriyama, Kiyofumi; Park, H.S.; Maruyama, Yu; Sugimoto, Jun

    1999-01-01

    A five-field simulation code JASMINE-pro has been developed at JAERI for the calculation of the propagation and explosion phase of steam explosions. The basic equations and the constitutive relationships specifically utilized in the propagation models in the code are introduced in this paper. Some calculations simulating the KROTOS 1D and 2D steam explosion experiments are also stated in the paper to show the present capability of the code. (author)

  18. TOWARD END-TO-END MODELING FOR NUCLEAR EXPLOSION MONITORING: SIMULATION OF UNDERGROUND NUCLEAR EXPLOSIONS AND EARTHQUAKES USING HYDRODYNAMIC AND ANELASTIC SIMULATIONS, HIGH-PERFORMANCE COMPUTING AND THREE-DIMENSIONAL EARTH MODELS

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, A; Vorobiev, O; Petersson, A; Sjogreen, B

    2009-07-06

    This paper describes new research being performed to improve understanding of seismic waves generated by underground nuclear explosions (UNE) by using full waveform simulation, high-performance computing and three-dimensional (3D) earth models. The goal of this effort is to develop an end-to-end modeling capability to cover the range of wave propagation required for nuclear explosion monitoring (NEM) from the buried nuclear device to the seismic sensor. The goal of this work is to improve understanding of the physical basis and prediction capabilities of seismic observables for NEM including source and path-propagation effects. We are pursuing research along three main thrusts. Firstly, we are modeling the non-linear hydrodynamic response of geologic materials to underground explosions in order to better understand how source emplacement conditions impact the seismic waves that emerge from the source region and are ultimately observed hundreds or thousands of kilometers away. Empirical evidence shows that the amplitudes and frequency content of seismic waves at all distances are strongly impacted by the physical properties of the source region (e.g. density, strength, porosity). To model the near-source shock-wave motions of an UNE, we use GEODYN, an Eulerian Godunov (finite volume) code incorporating thermodynamically consistent non-linear constitutive relations, including cavity formation, yielding, porous compaction, tensile failure, bulking and damage. In order to propagate motions to seismic distances we are developing a one-way coupling method to pass motions to WPP (a Cartesian anelastic finite difference code). Preliminary investigations of UNE's in canonical materials (granite, tuff and alluvium) confirm that emplacement conditions have a strong effect on seismic amplitudes and the generation of shear waves. Specifically, we find that motions from an explosion in high-strength, low-porosity granite have high compressional wave amplitudes and weak

  19. Development of tight-binding, chemical-reaction-dynamics simulator for combinatorial computational chemistry

    International Nuclear Information System (INIS)

    Kubo, Momoji; Ando, Minako; Sakahara, Satoshi; Jung, Changho; Seki, Kotaro; Kusagaya, Tomonori; Endou, Akira; Takami, Seiichi; Imamura, Akira; Miyamoto, Akira

    2004-01-01

    Recently, we have proposed a new concept called 'combinatorial computational chemistry' to realize a theoretical, high-throughput screening of catalysts and materials. We have already applied our combinatorial, computational-chemistry approach, mainly based on static first-principles calculations, to various catalysts and materials systems and its applicability to the catalysts and materials design was strongly confirmed. In order to realize more effective and efficient combinatorial, computational-chemistry screening, a high-speed, chemical-reaction-dynamics simulator based on quantum-chemical, molecular-dynamics method is essential. However, to the best of our knowledge, there is no chemical-reaction-dynamics simulator, which has an enough high-speed ability to perform a high-throughput screening. In the present study, we have succeeded in the development of a chemical-reaction-dynamics simulator based on our original, tight-binding, quantum-chemical, molecular-dynamics method, which is more than 5000 times faster than the regular first-principles, molecular-dynamics method. Moreover, its applicability and effectiveness to the atomistic clarification of the methanol-synthesis dynamics at reaction temperature were demonstrated

  20. Tc: chemistry and radiopharmaceuticals: a prospectus

    International Nuclear Information System (INIS)

    Tulip, T.H.

    1987-01-01

    The recent explosion in technetium chemistry evident in this symposium promises to continue unabated. As in the past, radiopharmaceutical applications will lead to new Tc chemistry. In this lecture the author will discuss those areas which appear most fertile based on chemical and radiopharmaceutical criteria. Among these will be new organometallic Tc chemistry (e.g., Tc(CNR) 6 cations), Tc complexes as metabolic tracers (e.g., Tc-analogs to FDG), and peptide-based Tc chelators (e.g., Tc-metallothionein)

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

    Energy Technology Data Exchange (ETDEWEB)

    Summa, Alexander; Hanke, Florian; Janka, Hans-Thomas; Melson, Tobias [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany); Marek, Andreas [Max Planck Computing and Data Facility (MPCDF), Gießenbachstr. 2, D-85748 Garching (Germany); Müller, Bernhard, E-mail: asumma@mpa-garching.mpg.de, E-mail: thj@mpa-garching.mpg.de [Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, Belfast, BT7 1NN (United Kingdom)

    2016-07-01

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

  2. Shock waves & explosions

    CERN Document Server

    Sachdev, PL

    2004-01-01

    Understanding the causes and effects of explosions is important to experts in a broad range of disciplines, including the military, industrial and environmental research, aeronautic engineering, and applied mathematics. Offering an introductory review of historic research, Shock Waves and Explosions brings analytic and computational methods to a wide audience in a clear and thorough way. Beginning with an overview of the research on combustion and gas dynamics in the 1970s and 1980s, the author brings you up to date by covering modeling techniques and asymptotic and perturbative methods and ending with a chapter on computational methods.Most of the book deals with the mathematical analysis of explosions, but computational results are also included wherever they are available. Historical perspectives are provided on the advent of nonlinear science, as well as on the mathematical study of the blast wave phenomenon, both when visualized as a point explosion and when simulated as the expansion of a high-pressure ...

  3. Explosive coalescence of Magnetic Islands

    International Nuclear Information System (INIS)

    Tajima, T.; Sakai, J.I.

    1985-04-01

    An explosive reconnection process associated with nonlinear evolution of the coalescence instability is found through studies of particle and magnetohydrodynamic simulations. The explosive coalescence is a self-similar process of magnetic collapse, in which the magnetic and electrostatic energies and temperatures explode toward the explosion time t 0 as (t 0 -t)/sup 8/3/,(t 0 -t) -4 , and (t 0 -t)/sup -8/3/, respectively. Ensuing amplitude oscillations in these quantities are identified by deriving an equation of motion for the scale factor in the Sagdeev potential

  4. Chemistry of high-energy materials. 2. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Klapoetke, Thomas M. [Munich Univ. (Germany). Chair of Inorganic Chemistry; Maryland Univ., College Park, MD (United States). Center of Energetic Concepts Development (CECD)

    2012-07-01

    This graduate-level textbook treats the basic chemistry of high energy materials - primary and secondary explosives, propellants, rocket fuel and pyrotechnics - and provides a review of new research developments. Applications in both military and civil fields are discussed. The book also offers new insights into ''green'' chemistry requirements and strategies for military applications.

  5. Determination of Quantum Chemistry Based Force Fields for Molecular Dynamics Simulations of Aromatic Polymers

    Science.gov (United States)

    Jaffe, Richard; Langhoff, Stephen R. (Technical Monitor)

    1995-01-01

    Ab initio quantum chemistry calculations for model molecules can be used to parameterize force fields for molecular dynamics simulations of polymers. Emphasis in our research group is on using quantum chemistry-based force fields for molecular dynamics simulations of organic polymers in the melt and glassy states, but the methodology is applicable to simulations of small molecules, multicomponent systems and solutions. Special attention is paid to deriving reliable descriptions of the non-bonded and electrostatic interactions. Several procedures have been developed for deriving and calibrating these parameters. Our force fields for aromatic polyimide simulations will be described. In this application, the intermolecular interactions are the critical factor in determining many properties of the polymer (including its color).

  6. Explosions on a gas-vacuum interface

    International Nuclear Information System (INIS)

    Nutt, G.; Klein, L.; Ratcliffe, A.E.

    1981-01-01

    A finite-difference computer code is used to calculate the time development of an explosion on a gas-vacuum interface. An analytic theory of the shape of the shock wave produced in the explosion is compared with the results of the computer simulation. The assumptions used in obtaining this analytic solution are verified, and the degree to which the variables describing the explosion are self-similar is examined. Finally, certain consistency relations among the similarity exponents are tested

  7. OCENER, a one-dimensional computer code for the numerical simulation of the mechanical effects of peaceful underground nuclear explosions in rocks

    International Nuclear Information System (INIS)

    Gupta, S.C.; Sikka, S.K.; Chidambaram, R.

    1979-01-01

    An account is given of a one-dimensional spherical symmetric computer code for the numerical simulation of the effects of peaceful underground nuclear explosions in rocks (OCENER). In the code, the nature of the stress field and response of the medium to this field are modelled numerically by finite difference form of the laws of continuum mechanics and the constitutive relations of the rock medium in which the detonation occurs. It enables to approximate well the cavity growth and fracturing of the surrounding rock for contained explosions and the events upto the time the spherical symmetry is valid for cratering-type explosions. (auth.)

  8. Health Consequences and Management of Explosive Events

    Directory of Open Access Journals (Sweden)

    Abbas Ostadtaghizadeh

    2016-01-01

    Conclusion: Because of the wide range and adverse impacts of explosions, healthcare authorities and staff should have a good grasp of preventive principles, as well as protection and management of explosion sites. Besides they have to be familiar with treating the injured. It is recommended that training courses and simulated explosive events be designed and run by the healthcare sector.

  9. The sensitivity studies of a landmine explosive detection system based on neutron backscattering using Monte Carlo simulation

    Directory of Open Access Journals (Sweden)

    Khan Hamda

    2017-01-01

    Full Text Available This paper carries out a Monte Carlo simulation of a landmine detection system, using the MCNP5 code, for the detection of concealed explosives such as trinitrotoluene and cyclonite. In portable field detectors, the signal strength of backscattered neutrons and gamma rays from thermal neutron activation is sensitive to a number of parameters such as the mass of explosive, depth of concealment, neutron moderation, background soil composition, soil porosity, soil moisture, multiple scattering in the background material, and configuration of the detection system. In this work, a detection system, with BF3 detectors for neutrons and sodium iodide scintillator for g-rays, is modeled to investigate the neutron signal-to-noise ratio and to obtain an empirical formula for the photon production rate Ri(n,γ= SfGfMf(d,m from radiative capture reactions in constituent nuclides of trinitrotoluene. This formula can be used for the efficient landmine detection of explosives in quantities as small as ~200 g of trinitrotoluene concealed at depths down to about 15 cm. The empirical formula can be embedded in a field programmable gate array on a field-portable explosives' sensor for efficient online detection.

  10. "Fooling fido"--chemical and behavioral studies of pseudo-explosive canine training aids.

    Science.gov (United States)

    Kranz, William D; Strange, Nicholas A; Goodpaster, John V

    2014-12-01

    Genuine explosive materials are traditionally employed in the training and testing of explosive-detecting canines so that they will respond reliably to these substances. However, challenges arising from the acquisition, storage, handling, and transportation of explosives have given rise to the development of "pseudo-explosive" training aids. These products attempt to emulate the odor of real explosives while remaining inert. Therefore, a canine trained on a pseudo-explosive should respond to its real-life analog. Similarly, a canine trained on an actual explosive should respond to the pseudo-explosive as if it was real. This research tested those assumptions with a focus on three explosives: single-base smokeless powder, 2,4,6-trinitrotoluene (TNT), and a RDX-based plastic explosive (Composition C-4). Using gas chromatography-mass spectrometry with solid phase microextraction as a pre-concentration technique, we determined that the volatile compounds given off by pseudo-explosive products consisted of various solvents, known additives from explosive formulations, and common impurities present in authentic explosives. For example, simulated smokeless powders emitted terpenes, 2,4-dinitrotoluene, diphenylamine, and ethyl centralite. Simulated TNT products emitted 2,4- and 2,6-dinitrotoluene. Simulated C-4 products emitted cyclohexanone, 2-ethyl-1-hexanol, and dimethyldinitrobutane. We also conducted tests to determine whether canines trained on pseudo-explosives are capable of alerting to genuine explosives and vice versa. The results show that canines trained on pseudo-explosives performed poorly at detecting all but the pseudo-explosives they are trained on. Similarly, canines trained on actual explosives performed poorly at detecting all but the actual explosives on which they were trained.

  11. Step-by-Step Simulation of Radiation Chemistry Using Green Functions for Diffusion-Influenced Reactions

    Science.gov (United States)

    Plante, Ianik; Cucinotta, Francis A.

    2011-01-01

    Radiolytic species are formed approximately 1 ps after the passage of ionizing radiation through matter. After their formation, they diffuse and chemically react with other radiolytic species and neighboring biological molecules, leading to various oxidative damage. Therefore, the simulation of radiation chemistry is of considerable importance to understand how radiolytic species damage biological molecules [1]. The step-by-step simulation of chemical reactions is difficult, because the radiolytic species are distributed non-homogeneously in the medium. Consequently, computational approaches based on Green functions for diffusion-influenced reactions should be used [2]. Recently, Green functions for more complex type of reactions have been published [3-4]. We have developed exact random variate generators of these Green functions [5], which will allow us to use them in radiation chemistry codes. Moreover, simulating chemistry using the Green functions is which is computationally very demanding, because the probabilities of reactions between each pair of particles should be evaluated at each timestep [2]. This kind of problem is well adapted for General Purpose Graphic Processing Units (GPGPU), which can handle a large number of similar calculations simultaneously. These new developments will allow us to include more complex reactions in chemistry codes, and to improve the calculation time. This code should be of importance to link radiation track structure simulations and DNA damage models.

  12. A hybrid formulation for the numerical simulation of condensed phase explosives

    Science.gov (United States)

    Michael, L.; Nikiforakis, N.

    2016-07-01

    In this article we present a new formulation and an associated numerical algorithm, for the simulation of combustion and transition to detonation of condensed-phase commercial- and military-grade explosives, which are confined by (or in general interacting with one or more) compliant inert materials. Examples include confined rate-stick problems and interaction of shock waves with gas cavities or solid particles in explosives. This formulation is based on an augmented Euler approach to account for the mixture of the explosive and its products, and a multi-phase diffuse interface approach to solve for the immiscible interaction between the mixture and the inert materials, so it is in essence a hybrid (augmented Euler and multi-phase) model. As such, it has many of the desirable features of the two approaches and, critically for our applications of interest, it provides the accurate recovery of temperature fields across all components. Moreover, it conveys a lot more physical information than augmented Euler, without the complexity of full multi-phase Baer-Nunziato-type models or the lack of robustness of augmented Euler models in the presence of more than two components. The model can sustain large density differences across material interfaces without the presence of spurious oscillations in velocity and pressure, and it can accommodate realistic equations of state and arbitrary (pressure- or temperature-based) reaction-rate laws. Under certain conditions, we show that the formulation reduces to well-known augmented Euler or multi-phase models, which have been extensively validated and used in practice. The full hybrid model and its reduced forms are validated against problems with exact (or independently-verified numerical) solutions and evaluated for robustness for rate-stick and shock-induced cavity collapse case-studies.

  13. Reaction chemistry of cerium

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-01-01

    It is truly ironic that a synthetic organic chemist likely has far greater knowledge of the reaction chemistry of cerium(IV) than an inorganic colleague. Cerium(IV) reagents have long since been employed as oxidants in effecting a wide variety of organic transformations. Conversely, prior to the late 1980s, the number of well characterized cerium(IV) complexes did not extend past a handful of known species. Though in many other areas, interest in the molecular chemistry of the 4f-elements has undergone an explosive growth over the last twenty years, the chemistry of cerium(IV) has for the most part been overlooked. This report describes reactions of cerium complexes and structure.

  14. A portable device for fast analysis of explosives in the environment

    Czech Academy of Sciences Publication Activity Database

    Čapka, Lukáš; Večeřa, Zbyněk; Mikuška, Pavel; Šesták, Jozef; Kahle, Vladislav; Bumbová, A.

    2015-01-01

    Roč. 1388, APR (2015), s. 167-173 ISSN 0021-9673 Institutional support: RVO:68081715 Keywords : analysis of explosives * portable device * chemiluminescence detector Subject RIV: CB - Analytical Chemistry , Separation Impact factor: 3.926, year: 2015

  15. Expansion shock waves in the implosion process from a time-reversible molecular-dynamics simulation of a dual explosion process

    International Nuclear Information System (INIS)

    Komatsu, Nobuyoshi; Abe, Takashi

    2007-01-01

    Why does not an expansion shock wave exist in a gaseous medium in nature? The reason has been widely believed to be the irreversibility in nature, while an obvious demonstration for this belief has not been accomplished yet. In order to resolve the question from a microscopic viewpoint, an implosion process dual to an explosion process was investigated by means of the molecular-dynamics method (MD). To this aim, we employed a ''bit-reversible algorithm (Bit MD)'' that was completely time-reversible in a microscopic viewpoint and was free from any round-off error. Here we show that, through a dual implosion simulation (i.e., a time-reversible simulation of the explosion), a kind of expansion shock wave is successfully formed in the Bit MD simulation. Furthermore, we show that when the controlled noise is intentionally added to the Bit MD, the expansion shock wave disappears dramatically and turns into an isentropic expansion wave, even if the noise is extremely small. Since the controlled noise gives rise to the irreversibility in the Bit MD simulation, it can be concluded that the irreversibility in the system prohibits the expansion shock wave from appearing in the system

  16. Performance properties of commercial explosives

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J.N.; Mader, C.L.; Goldstein, S.

    1983-01-01

    The aquarium test is a proven means of obtaining nonidial performance property data for commercial blasting agents. Optical data on the detonation velocity, shock wave in water, and expansion rate of the pipe enclosing the detonation products (in combination with the equilibrium thermodynamic chemistry code BKW) give the C-J state and degree of chemical reaction at the detonation front, as well as information on additional chemical reaction that occurs as the detonation products expand. Specific explosive systems that are studied are ammonium nitrate-fuel oil mixture (ANFO), aluminized ANFO, flaked trinitrotoluene (TNT), and several other commercial products in 10-cm diam and 20-cm-diam pipes of Plexiglas and clay. Experimental shock-pressure data are obtained with lithium niobate transducers placed in the water surrounding the explosive charge. These data show that the addition of approx.100-..mu..m aluminum particles to ANFO significantly increases the initial peak shock pressure delivered to the surrounding medium. Peak shock pressures in the water, calculated from the shock-wave orientation, are also useful in comparing performance properties of various commercial explosives. 20 references, 17 figures, 2 tables.

  17. Mesoscale modeling of metal-loaded high explosives

    Energy Technology Data Exchange (ETDEWEB)

    Bdzil, John Bohdan [Los Alamos National Laboratory; Lieberthal, Brandon [UNIV OF ILLINOIS; Srewart, Donald S [UNIV OF ILLINOIS

    2010-01-01

    We describe a 3D approach to modeling multi-phase blast explosive, which is primarily condensed explosive by volume with inert embedded particles. These embedded particles are uniform in size and placed on the array of a regular lattice. The asymptotic theory of detonation shock dynamics governs the detonation shock propagation in the explosive. Mesoscale hydrodynamic simulations are used to show how the particles are compressed, deformed, and accelerated by the high-speed detonation products flow.

  18. Simulation of stratospheric water vapor trends: impact on stratospheric ozone chemistry

    Directory of Open Access Journals (Sweden)

    A. Stenke

    2005-01-01

    Full Text Available A transient model simulation of the 40-year time period 1960 to 1999 with the coupled climate-chemistry model (CCM ECHAM4.L39(DLR/CHEM shows a stratospheric water vapor increase over the last two decades of 0.7 ppmv and, additionally, a short-term increase after major volcanic eruptions. Furthermore, a long-term decrease in global total ozone as well as a short-term ozone decline in the tropics after volcanic eruptions are modeled. In order to understand the resulting effects of the water vapor changes on lower stratospheric ozone chemistry, different perturbation simulations were performed with the CCM ECHAM4.L39(DLR/CHEM feeding the water vapor perturbations only to the chemistry part. Two different long-term perturbations of lower stratospheric water vapor, +1 ppmv and +5 ppmv, and a short-term perturbation of +2 ppmv with an e-folding time of two months were applied. An additional stratospheric water vapor amount of 1 ppmv results in a 5–10% OH increase in the tropical lower stratosphere between 100 and 30 hPa. As a direct consequence of the OH increase the ozone destruction by the HOx cycle becomes 6.4% more effective. Coupling processes between the HOx-family and the NOx/ClOx-family also affect the ozone destruction by other catalytic reaction cycles. The NOx cycle becomes 1.6% less effective, whereas the effectiveness of the ClOx cycle is again slightly enhanced. A long-term water vapor increase does not only affect gas-phase chemistry, but also heterogeneous ozone chemistry in polar regions. The model results indicate an enhanced heterogeneous ozone depletion during antarctic spring due to a longer PSC existence period. In contrast, PSC formation in the northern hemisphere polar vortex and therefore heterogeneous ozone depletion during arctic spring are not affected by the water vapor increase, because of the less PSC activity. Finally, this study shows that 10% of the global total ozone decline in the transient model run

  19. Large eddy simulation and experimental study on vented gasoline-air mixture explosions in a semi-confined obstructed pipe.

    Science.gov (United States)

    Li, Guoqing; Du, Yang; Wang, Shimao; Qi, Sheng; Zhang, Peili; Chen, Wenzhuo

    2017-10-05

    In this work, LES simulation coupled with a TFC sub-grid combustion model has been performed in a semi-confined pipe (L/D=10, V=10L) in the presence of four hollow-square obstacles (BR=49.8%) with circular hollow cross-section, in order to study the premixed gasoline-air mixture explosions. The comparisons between simulated results and experimental results have been conducted. It was found that the simulated results were in good agreement with experimental data in terms of flame structures, flame locations and overpressure time histories. Moreover, the interaction between flame propagation process and obstacles, overpressure dynamics were analyzed. In addition, the effects of initial gasoline vapor concentration (lean (ϕ=1.3%), stoichiometric (ϕ=1.7%) and rich (ϕ=2.1%)), and the number of obstacles (from 1 to 4) were also investigated by experiments. Some of the experimental results have been compared with the literature data. It is found that the explosion parameters of gasoline-air mixtures (e.g. the maximum overpressure peaks, average overpressure growth rates, etc.) are different from some other fuels such as hydrogen, methane and LPG, etc. Copyright © 2017. Published by Elsevier B.V.

  20. Simulation of Seismic Waves from Underground Explosions in Geologic Media: FY2009 Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, A; Vorobiev, O; Sjogreen, B; Petersson, N A

    2009-11-09

    This report summarizes work done after one year on project LL09-Sim-NDD-02 entitled 'Exploratory Research: Advanced Simulation of Low Yield Underground Nuclear Explosions To Improve Seismic Yield Estimation and Source Identification'. Work on this effort proceeded in two thrusts: (1) parametric studies of underground explosion generated motions with GEODYN; and (2) coupling of GEODYN to WPP. GEODYN is a code for modeling hydrodynamic (shock-wave) motions in a wide variety of materials, including earth materials. WPP is an anelastic finite difference code for modeling seismic motions. The sensitivity of seismic motions to emplacement conditions was investigated with a series of parametric studies of low-yield (0.2-4 kiloton) chemical high-explosive shots at a range of burial depths in four canonical geologic media (granite, limestone, tuff and alluvium). Results indicate that the material has a strong impact on the seismic motions consistent with previous reports. Motions computed with GEODYN in realistically complex material models are very consistent with reported motions from nuclear tests by Perret and Bass (1975). The amplitude, frequency content and cavity size resulting from explosions are all strongly sensitive to the material strength. Explosions in high-strength (granite) resulted in the highest amplitude, shortest duration pulse and smallest cavities, whereas explosions in low-strength material (alluvium) resulted in the lowest amplitudes, longest duration pulse and larger cavities. The corner frequencies of P-wave motions at take-off angles corresponding to propagation to teleseismic distances show corresponding behavior, with high-strength materials having the highest corner frequency and low-strength materials having low corner frequency. Gravity has an important effect on the cavity size and outgoing motions due work done against lithostatic stress. In fact without gravity the cavity radius and elastic motions are largely insensitive to

  1. Effects of Aircraft Wake Dynamics on Measured and Simulated NO(x) and HO(x) Wake Chemistry. Appendix B

    Science.gov (United States)

    Lewellen, D. C.; Lewellen, W. S.

    2001-01-01

    High-resolution numerical large-eddy simulations of the near wake of a B757 including simplified NOx and HOx chemistry were performed to explore the effects of dynamics on chemistry in wakes of ages from a few seconds to several minutes. Dilution plays an important basic role in the NOx-O3 chemistry in the wake, while a more interesting interaction between the chemistry and dynamics occurs for the HOx species. These simulation results are compared with published measurements of OH and HO2 within a B757 wake under cruise conditions in the upper troposphere taken during the Subsonic Aircraft Contrail and Cloud Effects Special Study (SUCCESS) mission in May 1996. The simulation provides a much finer grained representation of the chemistry and dynamics of the early wake than is possible from the 1 s data samples taken in situ. The comparison suggests that the previously reported discrepancy of up to a factor of 20 - 50 between the SUCCESS measurements of the [HO2]/[OH] ratio and that predicted by simplified theoretical computations is due to the combined effects of large mixing rates around the wake plume edges and averaging over volumes containing large species fluctuations. The results demonstrate the feasibility of using three-dimensional unsteady large-eddy simulations with coupled chemistry to study such phenomena.

  2. The simulation of air recirculation and fire/explosion phenomena within a semiconductor factory

    International Nuclear Information System (INIS)

    I, Yet-Pole; Chiu, Y.-L.; Wu, S.-J.

    2009-01-01

    The semiconductor industry is the collection of capital-intensive firms that employ a variety of hazardous chemicals and engage in the design and fabrication of semiconductor devices. Owing to its processing characteristics, the fully confined structure of the fabrication area (fab) and the vertical airflow ventilation design restrict the applications of traditional consequence analysis techniques that are commonly used in other industries. The adverse situation also limits the advancement of a fire/explosion prevention design for the industry. In this research, a realistic model of a semiconductor factory with a fab, sub-fabrication area, supply air plenum, and return air plenum structures was constructed and the computational fluid dynamics algorithm was employed to simulate the possible fire/explosion range and its severity. The semiconductor factory has fan module units with high efficiency particulate air filters that can keep the airflow uniform within the cleanroom. This condition was modeled by 25 fans, three layers of porous ceiling, and one layer of porous floor. The obtained results predicted very well the real airflow pattern in the semiconductor factory. Different released gases, leak locations, and leak rates were applied to investigate their influence on the hazard range and severity. Common mitigation measures such as a water spray system and a pressure relief panel were also provided to study their potential effectiveness to relieve thermal radiation and overpressure hazards within a fab. The semiconductor industry can use this simulation procedure as a reference on how to implement a consequence analysis for a flammable gas release accident within an air recirculation cleanroom

  3. Reactive Force Field for Liquid Hydrazoic Acid with Applications to Detonation Chemistry

    Science.gov (United States)

    Furman, David; Dubnikova, Faina; van Duin, Adri; Zeiri, Yehuda; Kosloff, Ronnie

    The development of a reactive force field (ReaxFF formalism) for Hydrazoic acid (HN3), a highly sensitive liquid energetic material, is reported. The force field accurately reproduces results of density functional theory (DFT) calculations. The quality and performance of the force field are examined by detailed comparison with DFT calculations related to uni, bi and trimolecular thermal decomposition routes. Reactive molecular dynamics (RMD) simulations are performed to reveal the initial chemical events governing the detonation chemistry of liquid HN3. The outcome of these simulations compares very well with recent results of tight-binding DFT molecular dynamics and thermodynamic calculations. Based on our RMD simulations, predictions were made for the activation energies and volumes in a broad range of temperatures and initial material compressions. Work Supported by The Center of Excellence for Explosives Detection, Mitigation and Response, Department of Homeland Security.

  4. Damage assessment of mission essential buildings based on simulation studies of low yield explosives

    Science.gov (United States)

    Allen, Thomas G. L.

    2006-04-01

    There has been a lack of investigations related to low yield explosives instigated by terrorist on small but high occupancy buildings. Also, mitigating the threat of terrorist attacks against high occupancy buildings with network equipment essential to the mission of an organization is a challenging task. At the same time, it is difficult to predict how, why, and when terrorists may attack theses assets. Many factors must be considered in creating a safe building environment. Although it is possible that the dominant threat mode may change in the future, bombings have historically been a favorite tactic of terrorists. Ingredients for homemade bombs are easily obtained on the open market, as are the techniques for making bombs. Bombings are easy and quick to execute. This paper discusses the problems with and provides insights of experience gained in analyzing small scale explosions on older military base buildings. In this study, we examine the placement of various bombs on buildings using the shock wave simulation code CTH and examine the damage effects on the interior of the building, particularly the damage that is incurred on a computer center. These simulation experiments provide data on the effectiveness of a building's security and an understanding of the phenomenology of shocks as they propagate through rooms and corridors. It's purpose is to motivate researchers to take the seriousness of small yield explosives on moderately sized buildings. Visualizations from this analysis are used to understand the complex flow of the air blasts around corridors and hallways. Finally, we make suggestions for improving the mitigation of such terrorist attacks. The intent of this study is not to provide breakthrough technology, but to provide a tool and a means for analyzing the material hardness of a building and to eventually provide the incentive for more security. The information mentioned in this paper is public domain information and easily available via the

  5. Hydrogen explosion testing with a simulated transuranic drum

    International Nuclear Information System (INIS)

    Dykes, K.L.; Meyer, M.L.

    1990-01-01

    Transuranic (TRU) waste generated at the Savannah River Site (SRS) is currently stored onsite for future retrieval and permanent disposal at the Waste Isolation Pilot Plant (WIPP). Some of the TRU waste is stored in vented 210-liter (55-gallon) drums and consists of gloves, wipes, plastic valves, tools, etc. Gas generation caused by radiolysis and biodegradation of these organic waste materials may produce a flammable hydrogen-air mixture (>4% v/v) in the multi-layer plastic waste bags. Using a worst case scenario, a drum explosion test program was carried out to determine the hydrogen concentration necessary to cause removal of the drum lid. Test results indicate an explosive mixture up to 15% v/v of hydrogen can be contained in an SRS TRU drum without total integrity failure via lid removal

  6. Core-Collapse Supernovae: Explosion dynamics, neutrinos and gravitational waves

    OpenAIRE

    Müller, Bernhard; Janka, Hans-Thomas; Marek, Andreas; Hanke, Florian; Wongwathanarat, Annop; Müller, Ewald

    2011-01-01

    The quest for the supernova explosion mechanism has been one of the outstanding challenges in computational astrophysics for several decades. Simulations have now progressed to a stage at which the solution appears close and neutrino and gravitational wave signals from self-consistent explosion models are becoming available. Here we focus one of the recent advances in supernova modeling, the inclusion of general relativity in multi-dimensional neutrino hydrodynamics simulations, and present t...

  7. On the prompt identification of traces of explosives

    Science.gov (United States)

    Trobajo, M. T.; López-Cabeceira, M. M.; Carriegos, M. V.; Díez-Machío, H.

    2014-12-01

    Some recent results in the use of Raman spectroscopy for recognition of explosives are reviewed. Experimental study using spectra data base has been developed. In order to simulate a more real situation, both blank substances and explosives substances have been considered in this research. Statistic classification techniques have been performed. Estimations of prediction errors were obtained by cross-validation methods. These results can be applied in airport security systems in order to prevent terror acts (by the detection of explosive/flammable substances).

  8. Experimental simulation of the energy parameters of the "ATLAS" capacitor bank using a disk explosive-magnetic generator

    CERN Document Server

    Buyko, A M; Gorbachev, Yu N; Yegorychev, B T; Zmushko, V V; Ivanov, V A; Ivanova, G G; Kuzaev, A I; Kulagin, A A; Mokhov, V N; Pavlii, V V; Pak, S V; Petrukhin, A A; Skobelev, A N; Sofronov, V N; Chernyshev, V K; Yakubov, V B; Anderson, B G; Atchison, W L; Clark, D A; Faehl, R J; Lindemuth, I R; Reinovsky, R E; Rodrigues, G; Stokes, J L; Tabaka, L J

    2001-01-01

    A joint US/Russian Advanced Liner Technology experiment ALT-1 was conducted to simulate the anticipated performance of the Atlas capacitor bank. A disk-explosive magnetic generator and foil opening switch were used to produce an electrical current waveform that reached a peak value of 32.5 MA and that imploded an aluminum liner to an inner surface velocity of 12 km/s. (6 refs).

  9. Physical explosion analysis in heat exchanger network design

    Science.gov (United States)

    Pasha, M.; Zaini, D.; Shariff, A. M.

    2016-06-01

    The failure of shell and tube heat exchangers is being extensively experienced by the chemical process industries. This failure can create a loss of production for long time duration. Moreover, loss of containment through heat exchanger could potentially lead to a credible event such as fire, explosion and toxic release. There is a need to analyse the possible worst case effect originated from the loss of containment of the heat exchanger at the early design stage. Physical explosion analysis during the heat exchanger network design is presented in this work. Baker and Prugh explosion models are deployed for assessing the explosion effect. Microsoft Excel integrated with process design simulator through object linking and embedded (OLE) automation for this analysis. Aspen HYSYS V (8.0) used as a simulation platform in this work. A typical heat exchanger network of steam reforming and shift conversion process was presented as a case study. It is investigated from this analysis that overpressure generated from the physical explosion of each heat exchanger can be estimated in a more precise manner by using Prugh model. The present work could potentially assist the design engineer to identify the critical heat exchanger in the network at the preliminary design stage.

  10. Climate effects of anthropogenic sulfate: Simulations from a coupled chemistry/climate model

    International Nuclear Information System (INIS)

    Chuang, C.C.; Penner, J.E.; Taylor, K.E.; Walton, J.J.

    1993-09-01

    In this paper, we use a more comprehensive approach by coupling a climate model with a 3-D global chemistry model to investigate the forcing by anthropogenic aerosol sulfate. The chemistry model treats the global-scale transport, transformation, and removal of SO 2 , DMS and H 2 SO 4 species in the atmosphere. The mass concentration of anthropogenic sulfate from fossil fuel combustion and biomass burning is calculated in the chemistry model and provided to the climate model where it affects the shortwave radiation. We also investigate the effect, with cloud nucleation parameterized in terms of local aerosol number, sulfate mass concentration and updraft velocity. Our simulations indicate that anthropogenic sulfate may result in important increases in reflected solar radiation, which would mask locally the radiative forcing from increased greenhouse gases. Uncertainties in these results will be discussed

  11. Modeling the explosion-source region: An overview

    International Nuclear Information System (INIS)

    Glenn, L.A.

    1993-01-01

    The explosion-source region is defined as the region surrounding an underground explosion that cannot be described by elastic or anelastic theory. This region extends typically to ranges up to 1 km/(kt) 1/3 but for some purposes, such as yield estimation via hydrodynamic means (CORRTEX and HYDRO PLUS), the maximum range of interest is less by an order of magnitude. For the simulation or analysis of seismic signals, however, what is required is the time resolved motion and stress state at the inelastic boundary. Various analytic approximations have been made for these boundary conditions, but since they rely on near-field empirical data they cannot be expected to reliably extrapolate to different explosion sites. More important, without some knowledge of the initial energy density and the characteristics of the medium immediately surrounding the explosion, these simplified models are unable to distinguish chemical from nuclear explosions, identify cavity decoupling, or account for such phenomena as anomalous dissipation via pore collapse

  12. The Titan Haze Simulation Experiment: Latest Laboratory Results and Dedicated Plasma Chemistry Model

    Science.gov (United States)

    Sciamma-O'Brien, Ella; Raymond, Alexander; Mazur, Eric; Salama, Farid

    2018-06-01

    Here, we present the latest results on the gas and solid phase analyses in the Titan Haze Simulation (THS) experiment. The THS experiment, developed at NASA Ames’ COSmIC facility is a unique experimental platform that allows us to simulate Titan’s complex atmospheric chemistry at Titan-like temperature (200 K) by cooling down N2-CH4-based mixtures in a supersonic expansion before inducing the chemistry by plasma.Gas phase: The residence time of the jet-accelerated gas in the active plasma region is less than 4 µs, which results in a truncated chemistry enabling us to control how far in the chain of reactions the chemistry is processing. By adding heavier molecules in the initial gas mixture, it is then possible to study the first and intermediate steps of Titan’s atmospheric chemistry as well as specific chemical pathways, as demonstrated by mass spectrometry and comparison to Cassini CAPS data [1]. A new model was recently developed to simulate the plasma chemistry in the THS. Calculated mass spectra produced by this model are in good agreement with the experimental THS mass spectra, confirming that the short residence time in the plasma cavity limits the growth of larger species [2].Solid phase: Scanning electron microscopy and infrared spectroscopy have been used to investigate the effect of the initial gas mixture on the morphology of the THS Titan aerosol analogs as well as on the level and nature of the nitrogen incorporation into these aerosols. A comparison to Cassini VIMS observational data has shown that the THS aerosols produced in simpler mixtures, i.e., that contain more nitrogen and where the N-incorporation is in isocyanide-type molecules instead of nitriles, are more representative of Titan’s aerosols [3]. In addition, a new optical constant facility has been developed at NASA Ames that allows us to determine the complex refractive indices of THS Titan aerosol analogs from NIR to FIR (0.76-222 cm-1). The facility and preliminary results

  13. Reaction chemistry of nitrogen species in hydrothermal systems: Simple reactions, waste simulants, and actual wastes

    International Nuclear Information System (INIS)

    Dell'Orco, P.; Luan, L.; Proesmans, P.; Wilmanns, E.

    1995-01-01

    Results are presented from hydrothermal reaction systems containing organic components, nitrogen components, and an oxidant. Reaction chemistry observed in simple systems and in simple waste simulants is used to develop a model which presents global nitrogen chemistry in these reactive systems. The global reaction path suggested is then compared with results obtained for the treatment of an actual waste stream containing only C-N-0-H species

  14. Mirrored continuum and molecular scale simulations of the ignition of gamma phase RDX

    Science.gov (United States)

    Stewart, D. Scott; Chaudhuri, Santanu; Joshi, Kaushik; Lee, Kibaek

    2017-01-01

    We describe the ignition of an explosive crystal of gamma-phase RDX due to a thermal hot spot with reactive molecular dynamics (RMD), with first-principles trained, reactive force field based molecular potentials that represents an extremely complex reaction network. The RMD simulation is analyzed by sorting molecular product fragments into high and low molecular weight groups, to represent identifiable components that can be interpreted by a continuum model. A continuum model based on a Gibbs formulation has a single temperature and stress state for the mixture. The continuum simulation that mirrors the atomistic simulation allows us to study the atomistic simulation in the familiar physical chemistry framework and provides an essential, continuum/atomistic link.

  15. Research topics in explosives - a look at explosives behaviors

    International Nuclear Information System (INIS)

    Maienschein, J L

    2014-01-01

    The behaviors of explosives under many conditions - e.g., sensitivity to inadvertent reactions, explosion, detonation - are controlled by the chemical and physical properties of the explosive materials. Several properties are considered for a range of improvised and conventional explosives. Here I compare these properties across a wide range of explosives to develop an understanding of explosive behaviors. For improvised explosives, which are generally heterogeneous mixtures of ingredients, a range of studies is identified as needed to more fully understand their behavior and properties. For conventional explosives, which are generally comprised of crystalline explosive molecules held together with a binder, I identify key material properties that determine overall sensitivity, including the extremely safe behavior of Insensitive High Explosives, and discuss an approach to predicting the sensitivity or insensitivity of an explosive.

  16. ''Water bath'' effect during the electrical underwater wire explosion

    International Nuclear Information System (INIS)

    Oreshkin, V. I.; Chaikovsky, S. A.; Ratakhin, N. A.; Grinenko, A.; Krasik, Ya. E.

    2007-01-01

    The results of a simulation of underwater electrical wire explosion at a current density >10 9 A/cm 2 , total discharge current of ∼3 MA, and rise time of the current of ∼100 ns are presented. The electrical wire explosion was simulated using a one-dimensional radiation-magnetohydrodynamic model. It is shown that the radiation of the exploded wire produces a thin conducting plasma shell in the water in the vicinity of the exploding wire surface. It was found that this plasma shell catches up to 30% of the discharge current. Nevertheless, it was shown that the pressure and temperature of the wire material remain unchanged as compared with the idealized case of the electrical wire explosion in vacuum. This result is explained by a 'water bath' effect

  17. 2D RADIATION-HYDRODYNAMIC SIMULATIONS OF SUPERNOVA SHOCK BREAKOUT IN BIPOLAR EXPLOSIONS OF A BLUE SUPERGIANT PROGENITOR

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Akihiro; Maeda, Keiichi [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto, 606-8502 (Japan); Shigeyama, Toshikazu [Research Center for the Early Universe, School of Science, University of Tokyo, Bunkyo-ku, Tokyo, 113-0033 (Japan)

    2016-07-10

    A two-dimensional special relativistic radiation-hydrodynamics code is developed and applied to numerical simulations of supernova shock breakout in bipolar explosions of a blue supergiant. Our calculations successfully simulate the dynamical evolution of a blast wave in the star and its emergence from the surface. Results of the model with spherical energy deposition show a good agreement with previous simulations. Furthermore, we calculate several models with bipolar energy deposition and compare their results with the spherically symmetric model. The bolometric light curves of the shock breakout emission are calculated by a ray-tracing method. Our radiation-hydrodynamic models indicate that the early part of the shock breakout emission can be used to probe the geometry of the blast wave produced as a result of the gravitational collapse of the iron core.

  18. Steam explosion triggering and efficiency studies

    International Nuclear Information System (INIS)

    Buxton, L.D.; Nelson, L.S.; Benedick, W.B.

    1979-01-01

    A program at Sandia Laboratories to provide relevant data on the interaction of molten LWR core materials with water is described. Two different subtasks were established. The first was the performance of laboratory-scale experiments to investigate the ability to trigger steam explosions for realistic LWR core melt simulants under a wide range of initial conditions. The second was the performance of field-scale experiments to investigate the efficiency of converting the thermal energy of the melt into mechanical work in much larger steam explosions

  19. Analysis of ventilation systems subjected to explosive transients: far-field analysis

    International Nuclear Information System (INIS)

    Tang, P.K.; Andrae, R.W.; Bolstad, J.W.; Duerre, K.H.; Gregory, W.S.

    1981-11-01

    Progress in developing a far-field explosion simulation computer code is outlined. The term far-field implies that this computer code is suitable for modeling explosive transients in ventilation systems that are far removed from the explosive event and are rather insensitive to the particular characteristics of the explosive event. This type of analysis is useful when little detailed information is available and the explosive event is described parametrically. The code retains all the features of the TVENT code and allows completely compressible flow with inertia and choking effects. Problems that illustrate the capabilities and limitations of the code are described

  20. The Interplay of Opacities and Rotation in Promoting the Explosion of Core-Collapse Supernovae

    Science.gov (United States)

    Vartanyan, David; Burrows, Adam; Radice, David

    2018-01-01

    For over five decades, the mechanism of explosion in core-collapse supernovae has been a central unsolved problem in astrophysics, challenging both our computational capabilities and our understanding of relevant physics. Current simulations often produce explosions, but they are at times underenergetic. The neutrino mechanism, wherein a fraction of emitted neutrinos is absorbed in the mantle of the star to reignite the stalled shock, remains the dominant model for reviving explosions in massive stars undergoing core collapse. We present here a diverse suite of 2D axisymmetric simulations produced by FORNAX, a highly parallelizable multidimensional supernova simulation code. We explore the effects of various corrections, including the many-body correction, to neutrino-matter opacities and the possible role of rotation in promoting explosion amongst various core-collapse progenitors.

  1. Seismic coupling of nuclear explosions

    International Nuclear Information System (INIS)

    Larson, D.B.

    1989-01-01

    The new Giant Magnet Experimental Facility employing digital recording of explosion induced motion has been constructed and successfully tested. Particle velocity and piezoresistance gage responses can be measured simultaneously thus providing the capability for determining the multi-component stress-strain history in the test material. This capability provides the information necessary for validation of computer models used in simulation of nuclear underground testing, chemical explosion testing, dynamic structural response, earth penetration response, and etc. This report discusses fully coupled and cavity decoupled explosions of the same energy (0.622 kJ) were carried out as experiments to study wave propagation and attenuation in polymethylmethacrylate (PMMA). These experiments produced particle velocity time histories at strains from 2 x 10 -3 to as low as 5.8 x 10 -6 . Other experiments in PMMA, reported recently by Stout and Larson 8 provide additional particle velocity data to strains of 10 -1

  2. Evaluation of ferrocyanide/nitrate explosive hazard

    International Nuclear Information System (INIS)

    Cady, H.H.

    1992-06-01

    Los Alamos National Laboratory agreed to assist Pacific Northwest Laboratory in the Ferrocyanide Safety Evaluation Program by helping to evaluate the explosive hazard of several mixtures of simulated ferrocyanide waste-tank sludge containing sodium nitrite and sodium nitrate. This report is an evaluation of the small-scale safety tests used to assess the safety of these materials from an explosive point of view. These tests show that these materials are not initiated by mechanical insult, and they require an external heat source before any exothermic chemical reaction can be observed

  3. Finite element investigation of explosively formed projectiles (EFP)

    International Nuclear Information System (INIS)

    Ahmad, I.

    1999-01-01

    This thesis report represents the numerical simulation of explosively formed projectiles (EFP), a type of linear self-forging fragment device. The simulation is performed using a finite element code DYNA2D. It also explicates that how the shape, velocity and kinetic energy of an explosively formed projectile is effected by various parameters. Different parameters investigated are mesh density, material, thickness, contour and types of liner. Effect of shape of casing and material model is also analyzed. The shapes of projectiles at different times after detonation are shown. The maximum velocity and kinetic energy of the projectile have been used to ascertain the effect of above mentioned parameters. (author)

  4. Simulation Study on the Deflection Response of the 921A Steel thin plate under Explosive Impact Load

    Science.gov (United States)

    Zhang, Yu-Xiang; Chen, Fang; Han, Yan

    2018-03-01

    The Ship cabin would be subject to high-intensity shock wave load when it is attacked by anti-ship weapons, causing its side board damaged. The time course of the deflection of the thin plate made of 921A steel in different initial conditions under the impact load is researched by theoretical analysis and numerical simulation. According to the theory of elastic-plastic deformation of the thin plate, the dynamic response equation of the thin plate under the explosion impact load is established with the method of energy, and the theoretical calculation value is compared with the result from the simulation method. It proved that the theoretical calculation method has better reliability and accuracy in different boundary size.

  5. Application of CPML to two-dimension numerical simulation of nuclear electromagnetic pulse from air explosions

    International Nuclear Information System (INIS)

    Gao Chunxia; Wang Lianghou

    2005-01-01

    The characteristics of different types of PML were analyzed and the convolutional PML was chosen to truncate the open boundaries in numerical simulation of nuclear electromagnetic pulse from air explosions. On the basis of the split-field PML and the plane-wave solution of electromagnetic field in free space, the unsplit-field PML was constructed. By applying the convolutional theorem of Fourier transform, the discrete iterative equations of electromagnetic field components were presented in the CPML media under the two-dimension prolate-spheroidal coordinate system. The numerical results indicate that the method of CPML can largely decrease calculation errors of boundary fields. (authors)

  6. Asymmetric explosion of core-collapse supernovae

    International Nuclear Information System (INIS)

    Kazeroni, Remi

    2016-01-01

    A core-collapse supernova represents the ultimate stage of the evolution of massive stars.The iron core contraction may be followed by a gigantic explosion which gives birth to a neutron star.The multidimensional dynamics of the innermost region, during the first hundreds milliseconds, plays a decisive role on the explosion success because hydrodynamical instabilities are able to break the spherical symmetry of the collapse. Large scale transverse motions generated by two instabilities, the neutrino-driven convection and the Standing Accretion Shock Instability (SASI),increase the heating efficiency up to the point of launching an asymmetric explosion and influencing the birth properties of the neutron star. In this thesis, hydrodynamical instabilities are studied using numerical simulations of simplified models. These models enable a wide exploration of the parameter space and a better physical understanding of the instabilities, generally inaccessible to realistic models.The non-linear regime of SASI is analysed to characterize the conditions under which a spiral mode prevails and to assess its ability to redistribute angular momentum radially.The influence of rotation on the shock dynamics is also addressed. For fast enough rotation rates, a corotation instability overlaps with SASI and greatly impacts the dynamics. The simulations enable to better constrain the effect of non-axisymmetric modes on the angular momentum budget of the iron core collapsing into a neutron star. SASI may under specific conditions spin up or down the pulsar born during the explosion. Finally, an idealised model of the heating region is studied to characterize the non-linear onset of convection by perturbations such as those produced by SASI or pre-collapse combustion inhomogeneities. The dimensionality issue is examined to stress the beneficial consequences of the three-dimensional dynamics on the onset of the explosion. (author) [fr

  7. Gas pressure from a nuclear explosion in oil shale

    International Nuclear Information System (INIS)

    Taylor, R.W.

    1975-01-01

    The quantity of gas and the gas pressure resulting from a nuclear explosion in oil shale is estimated. These estimates are based on the thermal history of the rock during and after the explosion and the amount of gas that oil shale releases when heated. It is estimated that for oil shale containing less than a few percent of kerogen the gas pressure will be lower than the hydrostatic pressure. A field program to determine the effects of nuclear explosions in rocks that simulate the unique features of oil shale is recommended. (U.S.)

  8. Explosions in Landau Vlasov dynamics

    International Nuclear Information System (INIS)

    Suraud, E.; Cussol, D.; Gregoire, C.; Boilley, D.; Pi, M.; Schuck, P.; Remaud, B.; Sebille, F.

    1988-01-01

    A microscopic study of the quasi-fusion/explosion transition is presented in the framework of Landau-Vlasov simulations of intermediate energy heavy-ion collisions (bombarding energies between 10 and 100 MeV/A). A detailed analysis in terms of the Equation of State of the system is performed. In agreement with schematic models we find that the composite nuclear system formed in the collision does explode when it stays long enough in the mechanically unstable region (spinodal region). Quantitative estimates of the explosion threshold are given for central symmetric reactions (Ca+Ca and Ar+Ti). The effect of the nuclear matter compressibility modulus is discussed

  9. New Mix Explosives for Explosive Welding

    Science.gov (United States)

    Andreevskikh, Leonid

    2011-06-01

    Suggested and tested were some mix explosives--powder mixtures of a brisant high explosive (HE = RDX, PETN) and an inert diluent (baking soda)--for use in explosive welding. RDX and PETN were selected in view of their high throwing ability and low critical diameter. Since the decomposition of baking soda yields a huge amount of gaseous products, its presence ensures (even at a low HE percentage) a throwing speed that is sufficient for realization of explosive welding, at a reduced brisant action of charge. Mix chargers containing 30-70 wt % HE (the rest baking soda) have been tested experimentally and optimized. For study of possibility to reduce critical diameter of HE mixture, the mixture was prepared where HE crystal sizes did not exceed 10 μm. The tests, which were performed with this HE, revealed that the mixture detonated stably with the velocity D ~ 2 km/s, if the layer thickness was d = 2 mm. The above explosives afford to markedly diminish deformations within the oblique impact zone and thus to carry out explosive welding of hollow items and thin metallic foils.

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

    Directory of Open Access Journals (Sweden)

    Qingjie Jiao

    2018-03-01

    Full Text Available 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.

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

    Science.gov (United States)

    Jiao, Qingjie; Wang, Qiushi; Nie, Jianxin; Guo, Xueyong; Zhang, Wei; Fan, Wenqi

    2018-03-01

    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.

  12. 78 FR 64246 - Commerce in Explosives; List of Explosives Materials

    Science.gov (United States)

    2013-10-28

    ..., including non-cap sensitive slurry and water gel explosives. Blasting caps. Blasting gelatin. Blasting.... Explosive conitrates. Explosive gelatins. Explosive liquids. Explosive mixtures containing oxygen-releasing... powder. [[Page 64247

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

    OpenAIRE

    Qingjie Jiao; Qiushi Wang; Jianxin Nie; Xueyong Guo; Wei Zhang; Wenqi Fan

    2018-01-01

    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-...

  14. An empirical fast-neutron technique for detection of explosive-like materials

    International Nuclear Information System (INIS)

    Hussein, E.M.A.; Lord, P.M.; Bot, D.L.

    1990-01-01

    A method for detecting explosives in airport baggage using fast-neutron scattering and transmission measurements is presented. Ammonium nitrate (a commercial fertilizer) is used in the laboratory to simulate an explosive-like substance. The measurements are combined in Cartesian maps of normalized pairs of measurements. The existence of fertilizer manifests itself in these maps within a distinct region which is not significantly altered by the presence of surrounding materials. Monte Carlo simulations further confirm this phenomenon. (orig.)

  15. Faster quantum chemistry simulation on fault-tolerant quantum computers

    International Nuclear Information System (INIS)

    Cody Jones, N; McMahon, Peter L; Yamamoto, Yoshihisa; Whitfield, James D; Yung, Man-Hong; Aspuru-Guzik, Alán; Van Meter, Rodney

    2012-01-01

    Quantum computers can in principle simulate quantum physics exponentially faster than their classical counterparts, but some technical hurdles remain. We propose methods which substantially improve the performance of a particular form of simulation, ab initio quantum chemistry, on fault-tolerant quantum computers; these methods generalize readily to other quantum simulation problems. Quantum teleportation plays a key role in these improvements and is used extensively as a computing resource. To improve execution time, we examine techniques for constructing arbitrary gates which perform substantially faster than circuits based on the conventional Solovay–Kitaev algorithm (Dawson and Nielsen 2006 Quantum Inform. Comput. 6 81). For a given approximation error ϵ, arbitrary single-qubit gates can be produced fault-tolerantly and using a restricted set of gates in time which is O(log ϵ) or O(log log ϵ); with sufficient parallel preparation of ancillas, constant average depth is possible using a method we call programmable ancilla rotations. Moreover, we construct and analyze efficient implementations of first- and second-quantized simulation algorithms using the fault-tolerant arbitrary gates and other techniques, such as implementing various subroutines in constant time. A specific example we analyze is the ground-state energy calculation for lithium hydride. (paper)

  16. A strategy for the application of steam explosion codes to reactor analysis

    International Nuclear Information System (INIS)

    Moriyama, Kiyofumi; Nakamura, Hideo

    2006-01-01

    A technical view on the strategy for the application of steam explosion codes for plant scale analysis is described. It includes assumption of triggering at the time of peak premixed melt mass, tuning of the explosion model on typical alumina steam explosion data, consideration of void and solidification effects as primary mechanism to limit the premixed mass and explosion energetics, choice of simple heat partition models affecting evaporation. The view was developed through experiences in development, verification and application of a steam explosion simulation code, JASMINE, at Japan Atomic Energy Agency (JAEA), as well as participation in OECD SERENA Phase-1 program. (author)

  17. Atmospheric Pressure Chemical Ionization Sources Used in The Detection of Explosives by Ion Mobility Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Waltman, Melanie J. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States)

    2010-05-01

    Explosives detection is a necessary and wide spread field of research. From large shipping containers to airline luggage, numerous items are tested for explosives every day. In the area of trace explosives detection, ion mobility spectrometry (IMS) is the technique employed most often because it is a quick, simple, and accurate way to test many items in a short amount of time. Detection by IMS is based on the difference in drift times of product ions through the drift region of an IMS instrument. The product ions are created when the explosive compounds, introduced to the instrument, are chemically ionized through interactions with the reactant ions. The identity of the reactant ions determines the outcomes of the ionization process. This research investigated the reactant ions created by various ionization sources and looked into ways to manipulate the chemistry occurring in the sources.

  18. Steel corrosion products solubility under conditions simulating various water chemistry parameters in power plants

    International Nuclear Information System (INIS)

    Slobodov, A.A.; Kritskij, V.G.; Zarembo, V.I.; Puchkov, L.V.

    1988-01-01

    To simulate construction material corrosion product mass transfer model in power plant circuits calculation of iron oxide and hydroxide solubility, depending on water chemistry parameters: temperature, pH-value, content of dissolved in water hydrogen and oxygen, is carried out

  19. Explosive nucleosynthesis in a neutrino-driven core collapse supernova

    International Nuclear Information System (INIS)

    Fujimoto, Shin-ichiro; Kotake, Kei; Hashimoto, Masa-aki; Ono, Masaomi; Ohnishi, Naofumi

    2010-01-01

    We investigate explosive nucleosynthesis in a delayed neutrino-driven, supernova explosion aided by standing accretion shock instability (SASI), based on two-dimensional hydrodynamic simulations of the explosion of a 15 M · star. We take into accounts neutrino heating and cooling as well as change in electron fraction due to weak interactions appropriately, in the two-dimensional simulations. We assume the isotropic emission of neutrinos from the neutrino spheres with given luminosities. and the Fermi-Dirac distribution of given temperatures. We find that the stalled shock revives due to the neutrino heating aided by SASI for cases with L νe ≥3.9x10 52 ergss -1 and the as-pherical shock passes through the outer layers of the star (≥10,000 km), with the explosion energies of ∼10 51 ergs.Next we examine abundances and masses of the supernova ejecta. We find that masses of the ejecta and 56 Ni correlate with the neutrino luminosity, and 56 Ni mass is comparable to that observed in SN 1987A. We also find that abundance pattern of the supernova ejecta is similar to that of the solar system, for cases with high explosion energies of >10 51 ergs. We emphasize that 64 Zn, which is underproduced in the spherical case, is abundantly produced in slightly neutron-rich ejecta.

  20. Modelling of turbulence and combustion for simulation of gas explosions in complex geometries

    Energy Technology Data Exchange (ETDEWEB)

    Arntzen, Bjoern Johan

    1998-12-31

    This thesis analyses and presents new models for turbulent reactive flows for CFD (Computational Fluid Dynamics) simulation of gas explosions in complex geometries like offshore modules. The course of a gas explosion in a complex geometry is largely determined by the development of turbulence and the accompanying increased combustion rate. To be able to model the process it is necessary to use a CFD code as a starting point, provided with a suitable turbulence and combustion model. The modelling and calculations are done in a three-dimensional finite volume CFD code, where complex geometries are represented by a porosity concept, which gives porosity on the grid cell faces, depending on what is inside the cell. The turbulent flow field is modelled with a k-{epsilon} turbulence model. Subgrid models are used for production of turbulence from geometry not fully resolved on the grid. Results from laser doppler anemometry measurements around obstructions in steady and transient flows have been analysed and the turbulence models have been improved to handle transient, subgrid and reactive flows. The combustion is modelled with a burning velocity model and a flame model which incorporates the burning velocity into the code. Two different flame models have been developed: SIF (Simple Interface Flame model), which treats the flame as an interface between reactants and products, and the {beta}-model where the reaction zone is resolved with about three grid cells. The flame normally starts with a quasi laminar burning velocity, due to flame instabilities, modelled as a function of flame radius and laminar burning velocity. As the flow field becomes turbulent, the flame uses a turbulent burning velocity model based on experimental data and dependent on turbulence parameters and laminar burning velocity. The laminar burning velocity is modelled as a function of gas mixture, equivalence ratio, pressure and temperature in reactant. Simulations agree well with experiments. 139

  1. The Impact of Learner's Prior Knowledge on Their Use of Chemistry Computer Simulations: A Case Study

    Science.gov (United States)

    Liu, Han-Chin; Andre, Thomas; Greenbowe, Thomas

    2008-01-01

    It is complicated to design a computer simulation that adapts to students with different characteristics. This study documented cases that show how college students' prior chemistry knowledge level affected their interaction with peers and their approach to solving problems with the use of computer simulations that were designed to learn…

  2. THE BIGGEST EXPLOSIONS IN THE UNIVERSE

    International Nuclear Information System (INIS)

    Johnson, Jarrett L.; Whalen, Daniel J.; Smidt, Joseph; Even, Wesley; Fryer, Chris L.; Heger, Alex; Chen, Ke-Jung

    2013-01-01

    Supermassive primordial stars are expected to form in a small fraction of massive protogalaxies in the early universe, and are generally conceived of as the progenitors of the seeds of supermassive black holes (BHs). Supermassive stars with masses of ∼55, 000 M ☉ , however, have been found to explode and completely disrupt in a supernova (SN) with an energy of up to ∼10 55 erg instead of collapsing to a BH. Such events, ∼10, 000 times more energetic than typical SNe today, would be among the biggest explosions in the history of the universe. Here we present a simulation of such a SN in two stages. Using the RAGE radiation hydrodynamics code, we first evolve the explosion from an early stage through the breakout of the shock from the surface of the star until the blast wave has propagated out to several parsecs from the explosion site, which lies deep within an atomic cooling dark matter (DM) halo at z ≅ 15. Then, using the GADGET cosmological hydrodynamics code, we evolve the explosion out to several kiloparsecs from the explosion site, far into the low-density intergalactic medium. The host DM halo, with a total mass of 4 × 10 7 M ☉ , much more massive than typical primordial star-forming halos, is completely evacuated of high-density gas after ∼ ☉ after ∼> 70 Myr. The chemical signature of supermassive star explosions may be found in such long-lived second-generation stars today

  3. Three-dimensional simulations of rapidly rotating core-collapse supernovae: finding a neutrino-powered explosion aided by non-axisymmetric flows

    Science.gov (United States)

    Takiwaki, Tomoya; Kotake, Kei; Suwa, Yudai

    2016-09-01

    We report results from a series of three-dimensional (3D) rotational core-collapse simulations for 11.2 and 27 M⊙ stars employing neutrino transport scheme by the isotropic diffusion source approximation. By changing the initial strength of rotation systematically, we find a rotation-assisted explosion for the 27 M⊙ progenitor , which fails in the absence of rotation. The unique feature was not captured in previous two-dimensional (2D) self-consistent rotating models because the growing non-axisymmetric instabilities play a key role. In the rapidly rotating case, strong spiral flows generated by the so-called low T/|W| instability enhance the energy transport from the proto-neutron star (PNS) to the gain region, which makes the shock expansion more energetic. The explosion occurs more strongly in the direction perpendicular to the rotational axis, which is different from previous 2D predictions.

  4. Multidimensional simulations of core-collapse supernovae with CHIMERA

    Science.gov (United States)

    Lentz, Eric J.; Bruenn, S. W.; Yakunin, K.; Endeve, E.; Blondin, J. M.; Harris, J. A.; Hix, W. R.; Marronetti, P.; Messer, O. B.; Mezzacappa, A.

    2014-01-01

    Core-collapse supernovae are driven by a multidimensional neutrino radiation hydrodynamic (RHD) engine, and full simulation requires at least axisymmetric (2D) and ultimately symmetry-free 3D RHD simulation. We present recent and ongoing work with our multidimensional RHD supernova code CHIMERA to understand the nature of the core-collapse explosion mechanism and its consequences. Recently completed simulations of 12-25 solar mass progenitors(Woosley & Heger 2007) in well resolved (0.7 degrees in latitude) 2D simulations exhibit robust explosions meeting the observationally expected explosion energy. We examine the role of hydrodynamic instabilities (standing accretion shock instability, neutrino driven convection, etc.) on the explosion dynamics and the development of the explosion energy. Ongoing 3D and 2D simulations examine the role that simulation resolution and the removal of the imposed axisymmetry have in the triggering and development of an explosion from stellar core collapse. Companion posters will explore the gravitational wave signals (Yakunin et al.) and nucleosynthesis (Harris et al.) of our simulations.

  5. Explosives detection through fast-neutron time-of-flight attenuation measurements

    International Nuclear Information System (INIS)

    Overley, J.C.; Chmelik, M.S.; Rasmussen, R.J.; Schofield, R.M.S.; Lefevre, H.W.

    1995-01-01

    Computer simulations have been used to devise an algorithm for detection of explosives in luggage which is based upon measured projected number densities of H, C, N, and O. Other elements are lumped together as projection X. Dependence on luggage-thickness is reduced by normalizing the projection for each element by the total. Normalization constrains projections to a 4-dimensional space. Distributions of nonexplosive (N) and explosive (E) situations are generated by sorting results of simulations into bins in that 4-space. A detection matrix element, given by the ratio E/(N+E) for each bin, is addressed by a measurement. For a realistic distribution of the numbers and types of luggage materials, the plastic explosive RDX, at 10% of suitcase thickness, can be detected in a single pixel with 85% reliability and a false alarm rate of 3%. (orig.)

  6. Multi-phase chemistry in process simulation - MASIT04 (VISTA)

    Energy Technology Data Exchange (ETDEWEB)

    Brink, A.; Li Bingzhi; Hupa, M. (Aabo Akademi University, Combustion and Materials Chemistry, Turku (Finland)) (and others)

    2008-07-01

    A new generation of process models has been developed by using advanced multi-phase thermochemistry. The generality of the thermodynamic free energy concept enables use of common software tools for high and low temperature processes. Reactive multi-phase phenomena are integrated to advanced simulation procedures by using local equilibrium or constrained state free energy computation. The high-temperature applications include a process model for the heat recovery of copper flash smelting and coupled models for converter and bloom casting operations in steel-making. Wet suspension models are developed for boiler and desalination water chemistry, flash evaporation of black liquor and for selected fibre-line and paper-making processes. The simulation combines quantitative physical and chemical data from reactive flows to form their visual images, thus providing efficient tools for engineering design and industrial decision-making. Economic impacts are seen as both better process operations and improved end products. The software tools developed are internationally commercialised and being used to support Finnish process technology exports. (orig.)

  7. Primary explosives

    Energy Technology Data Exchange (ETDEWEB)

    Matyas, Robert; Pachman, Jiri [Pardubice Univ. (Czech Republic). Faculty of Chemical Technology

    2013-06-01

    The first chapter provides background such as the basics of initiation and differences between requirements on primary explosives used in detonators and igniters. The authors then clarify the influence of physical characteristics on explosive properties, focusing on those properties required for primary explosives. Furthermore, the issue of sensitivity is discussed. All the chapters on particular groups of primary explosives are structured in the same way, including introduction, physical and chemical properties, explosive properties, preparation and documented use.

  8. Thermodynamics of Small Alkali Metal Halide Cluster Ions: Comparison of Classical Molecular Simulations with Experiment and Quantum Chemistry

    Czech Academy of Sciences Publication Activity Database

    Vlček, L.; Uhlík, F.; Moučka, F.; Nezbeda, Ivo; Chialvo, L.

    2015-01-01

    Roč. 119, č. 3 (2015), s. 488-500 ISSN 1089-5639 Institutional support: RVO:67985858 Keywords : monte-carlo simulations * molecular-dynamic simulations * classical drude oscillators Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.883, year: 2015

  9. Analysis of KROTOS KS-2 and KS-4 steam explosion experiments with TEXAS-VI

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ronghua, E-mail: rhchen@mail.xjtu.edu.cn [State Key Laboratory of Multiphase Flow in Power Engineering, School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Wang, Jun [Nuclear Engineering and Engineering Physics, College of Engineering, University of Wisconsin Madison, WI 53706 (United States); Su, G.H.; Qiu, Suizheng [State Key Laboratory of Multiphase Flow in Power Engineering, School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Corradini, M.L., E-mail: Corradini@engr.wisc.edu [Nuclear Engineering and Engineering Physics, College of Engineering, University of Wisconsin Madison, WI 53706 (United States)

    2016-12-01

    Highlights: • The KS-2 and KS-4 steam explosion experiments were analyzed by TEXAS-VI. • The coarse mixing status up to the explosion triggering time was well predicted by TEXAS-VI. • The predicted dynamic explosion pressure was in good agreement with the experimental results. - Abstract: TEXAS-VI is a transient, three-field, one-dimensional mechanistic model for the steam explosion phenomena. A fuel solidification model and associated fragmentation criteria of the solidifying particle for both the mixing phase and explosion phase were developed and incorporated into TEXAS-VI to account for solidification. In the present study, TEXAS-VI was used to analyze the KS-2 and KS-4 steam explosion experiments, which were performed in the KROTOS facility as part of the OECD-SERENA-2 program. In the simulation, the KROTOS experimental facility was modeled as Eulerian control volumes based on the facility geometry. The molten corium jet was divided up into a series of LaGrangian master particles equal to the initial jet diameter. Both the mixing phase and the explosion phase of the experiments were simulated by TEXAS-VI. Comparison to test data indicates that the fuel jet kinematics and the vapor volume during the mixing phase were well predicted by TEXAS-VI. The TEXAS-VI prediction of the dynamic explosion pressure at different axial locations in the test was also in good agreement with the experimental results. The maximum pressure of KS-2 and KS-4 predicted by TEXAS-VI were 16.7 MPa and 41.9 MPa, respectively. The KS-4 maximum steam explosion pressure predicted by TEXAS-VI was higher than that of KS-2, which was consistent with experiment observation. The observed differences of the dynamic explosion pressure between the KS-2 and KS-4 experiments were also successfully simulated by TEXAS-VI. This suggests that TEXAS-VI is able to analyze the effect of prototypic melt compositions on the steam explosion phenomena. Additional benchmarking and evaluations are ongoing.

  10. Magnetorotational Explosions of Core-Collapse Supernovae

    Directory of Open Access Journals (Sweden)

    Gennady S. Bisnovatyi-Kogan

    2014-12-01

    Full Text Available Core-collapse supernovae are accompanied by formation of neutron stars. The gravitation energy is transformed into the energy of the explosion, observed as SN II, SN Ib,c type supernovae. We present results of 2-D MHD simulations, where the source of energy is rotation, and magnetic eld serves as a "transition belt" for the transformation of the rotation energy into the energy of the explosion. The toroidal part of the magnetic energy initially grows linearly with time due to dierential rotation. When the twisted toroidal component strongly exceeds the poloidal eld, magneto-rotational instability develops, leading to a drastic acceleration in the growth of magnetic energy. Finally, a fast MHD shock is formed, producing a supernova explosion. Mildly collimated jet is produced for dipole-like type of the initial field. At very high initial magnetic field no MRI development was found.

  11. Nanopowder synthesis based on electric explosion technology

    Science.gov (United States)

    Kryzhevich, D. S.; Zolnikov, K. P.; Korchuganov, A. V.; Psakhie, S. G.

    2017-10-01

    A computer simulation of the bicomponent nanoparticle formation during the electric explosion of copper and nickel wires was carried out. The calculations were performed in the framework of the molecular dynamics method using many-body potentials of interatomic interaction. As a result of an electric explosion of dissimilar metal wires, bicomponent nanoparticles having different stoichiometry and a block structure can be formed. It is possible to control the process of destruction and the structure of the formed bicomponent nanoparticles by varying the distance between the wires and the loading parameters.

  12. Research on Initiation Sensitivity of Solid Explosive and Planer Initiation System

    Directory of Open Access Journals (Sweden)

    N Matsuo

    2016-09-01

    Full Text Available Firstly, recently, there are a lot of techniques being demanded for complex process, various explosive initiation method and highly accurate control of detonation are needed. In this research, the metal foil explosion using high current is focused attention on the method to obtain linear or planate initiation easily, and the main evaluation of metal foil explosion to initiate explosive was conducted. The explosion power was evaluated by observing optically the underwater shock wave generated from the metal foil explosion. Secondly, in high energy explosive processing, there are several applications, such as shock compaction, explosive welding, food processing and explosive forming. In these explosive applications, a high sensitive explosive has been mainly used. The high sensitive explosive is so dangerous, since it can lead to explosion suddenly. So, for developing explosives, the safety is the most important thing as well as low manufacturing cost and explosive characteristics. In this work, we have focused on the initiation sensitivity of a solid explosive and performed numerical analysis of sympathetic detonation. The numerical analysis is calculated by LS-DYNA 3D (commercial code. To understand the initiation reaction of an explosive, Lee-Tarver equation was used and impact detonation process was analyzed by ALE code. Configuration of simulation model is a quarter of circular cylinder. The donor type of explosive (SEP was used as initiation explosive. When the donor explosive is exploded, a shock wave is generated and it propagates into PMMA, air and metallic layers in order. During passing through the layers, the shock wave is attenuated and finally, it has influence on the acceptor explosive, Comp. B. Here, we evaluate the initiation of acceptor explosive and discuss about detonation pressure, reactive rate of acceptor explosive and attenuation of impact pressure.

  13. The metod development for determination of diazodinitrofenol explosive

    OpenAIRE

    Ihnát, Lukáš

    2012-01-01

    Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Analytical Chemistry Consultant: Doc. RNDr. Dalibor Šatínský, PhD. Diploma Thesis Title: The method development for determination of diazodinitrofenol explosive A new HPLC method for determination of diazodinitrophenol alongside with sodium picramate was developed and optimized. Column Ascentis® Express C18 10cm x 3mm; 2.7µm particles was select as most suitable one. Detection of compounds was performed at 220 nm...

  14. Summary of efficiency testing of standard and high-capacity high-efficiency particulate air filters subjected to simulated tornado depressurization and explosive shock waves

    International Nuclear Information System (INIS)

    Smith, P.R.; Gregory, W.S.

    1985-04-01

    Pressure transients in nuclear facility air cleaning systems can originate from natural phenomena such as tornadoes or from accident-induced explosive blast waves. This study was concerned with the effective efficiency of high-efficiency particulate air (HEPA) filters during pressure surges resulting from simulated tornado and explosion transients. The primary objective of the study was to examine filter efficiencies at pressure levels below the point of structural failure. Both standard and high-capacity 0.61-m by 0.61-m HEPA filters were evaluated, as were several 0.2-m by 0.2-m HEPA filters. For a particular manufacturer, the material release when subjected to tornado transients is the same (per unit area) for both the 0.2-m by 0.2-m and the 0.61-m by 0.61-m filters. For tornado transients, the material release was on the order of micrograms per square meter. When subjecting clean HEPA filters to simulated tornado transients with aerosol entrained in the pressure pulse, all filters tested showed a degradation of filter efficiency. For explosive transients, the material release from preloaded high-capacity filters was as much as 340 g. When preloaded high-capacity filters were subjected to shock waves approximately 50% of the structural limit level, 1 to 2 mg of particulate was released

  15. Implementation of an Online Chemistry Model to a Large Eddy Simulation Model (PALM-4U0

    Science.gov (United States)

    Mauder, M.; Khan, B.; Forkel, R.; Banzhaf, S.; Russo, E. E.; Sühring, M.; Kanani-Sühring, F.; Raasch, S.; Ketelsen, K.

    2017-12-01

    Large Eddy Simulation (LES) models permit to resolve relevant scales of turbulent motion, so that these models can capture the inherent unsteadiness of atmospheric turbulence. However, LES models are so far hardly applied for urban air quality studies, in particular chemical transformation of pollutants. In this context, BMBF (Bundesministerium für Bildung und Forschung) funded a joint project, MOSAIK (Modellbasierte Stadtplanung und Anwendung im Klimawandel / Model-based city planning and application in climate change) with the main goal to develop a new highly efficient urban climate model (UCM) that also includes atmospheric chemical processes. The state-of-the-art LES model PALM; Maronga et al, 2015, Geosci. Model Dev., 8, doi:10.5194/gmd-8-2515-2015), has been used as a core model for the new UCM named as PALM-4U. For the gas phase chemistry, a fully coupled 'online' chemistry model has been implemented into PALM. The latest version of the Kinetic PreProcessor (KPP) Version 2.3, has been utilized for the numerical integration of chemical species. Due to the high computational demands of the LES model, compromises in the description of chemical processes are required. Therefore, a reduced chemistry mechanism, which includes only major pollutants namely O3, NO, NO2, CO, a highly simplified VOC chemistry and a small number of products have been implemented. This work shows preliminary results of the advection, and chemical transformation of atmospheric pollutants. Non-cyclic boundaries have been used for inflow and outflow in east-west directions while periodic boundary conditions have been implemented to the south-north lateral boundaries. For practical applications, our approach is to go beyond the simulation of single street canyons to chemical transformation, advection and deposition of air pollutants in the larger urban canopy. Tests of chemistry schemes and initial studies of chemistry-turbulence, transport and transformations are presented.

  16. Coulomb explosion during the early stages of the reaction of alkali metals with water

    Czech Academy of Sciences Publication Activity Database

    Mason, Philip E.; Uhlig, Frank; Vaněk, Václav; Buttersack, T.; Bauerecker, S.; Jungwirth, Pavel

    2015-01-01

    Roč. 7, č. 3 (2015), s. 250-254 ISSN 1755-4330 R&D Projects: GA ČR GBP208/12/G016 Institutional support: RVO:61388963 Keywords : sodium-potasium alloy * water * coulomb explosion * high-speed camera * molecular dynamics Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 27.893, year: 2015

  17. Equations of state for detonation products of high energy PBX explosives

    Energy Technology Data Exchange (ETDEWEB)

    Lee, E. L.; Helm, F. H.; Finger, M.; Walton, J. R.

    1977-08-01

    It has become apparent that the accumulated changes in the analysis of cylinder test data, in the material specifications, and in the hydrodynamic code simulation of the cylinder test necessitated an update of the detonation product EOS description for explosives in common use at LLL. The explosives reviewed are PBX-9404-3, LX-04-1, LX-10-1, LX-14-0 and LX-09-1. In order to maintain the proper relation of predicted performance of these standard explosives, they have been revised as a single set.

  18. Numerical Simulation of Energy Conversion Mechanism in Electric Explosion

    Science.gov (United States)

    Wanjun, Wang; Junjun, Lv; Mingshui, Zhu; Qiubo, Fu; EFIs Integration R&D Group Team

    2017-06-01

    Electric explosion happens when micron-scale metal films such as copper film is stimulated by short-time current pulse, while generating high temperature and high pressure plasma. The expansion process of the plasma plays an important role in the study of the generation of shock waves and the study of the EOS of matter under high pressure. In this paper, the electric explosion process is divided into two stages: the energy deposition stage and the quasi-isentropic expansion stage, and a dynamic EOS of plasma considering the energy replenishment is established. On this basis, flyer driven by plasma is studied numerically, the pressure and the internal energy of plasma in the energy deposition stage and the quasi - isentropic expansion stage are obtained by comparing the velocity history of the flyer with the experimental results. An energy conversion model is established, and the energy conversion efficiency of each process is obtained, and the influence of impedance matching relationship between flyer and metal plasma on the energy conversion efficiency is proposed in this paper.

  19. Detection of hidden explosives by fast neutron activation analysis

    International Nuclear Information System (INIS)

    Li Xinnian; Guo Junpeng; Luo Wenyun; Wang Chuanshan; Fang Xiaoming; Yu Tailiu

    2008-01-01

    The paper describes the method and principle for detection of hidden explosive by fast neutron activation analysis (FNAA). The method of detection of explosives by FNAA has the specific properties of simple determination equipments, high reliability, and low detecting cost, and would be beneficial to the applicability and popularization in the field of protecting and securing nation. The contents of nitrogen and oxygen in four explosives, more then ten common materials and TNT samples covered with soil, were measured by FNAA. 14 MeV fast neutrons were generated from (d, t) reaction with a 400 kV Cockcroft Walton type accelerator. The two-dimension distributions for nitro- gen and oxygen counting rates per unit mass of determined matters were obtained, and the characteristic area of explosives and non-explosives can be defined. By computer aided pattern recognition, the samples were identified with low false alarm or omission rates. The Monte-Carlo simulation indicates that there is no any radiation at 15 m apart from neutron source and is safe for irradiation after 1 h. It is suggested that FNAA may be potential in remote controlling for detection hidden explosive system with multi-probe large array. (authors)

  20. Monte Carlo simulation of chemistry following radiolysis with TOPAS-nBio

    Science.gov (United States)

    Ramos-Méndez, J.; Perl, J.; Schuemann, J.; McNamara, A.; Paganetti, H.; Faddegon, B.

    2018-05-01

    Simulation of water radiolysis and the subsequent chemistry provides important information on the effect of ionizing radiation on biological material. The Geant4 Monte Carlo toolkit has added chemical processes via the Geant4-DNA project. The TOPAS tool simplifies the modeling of complex radiotherapy applications with Geant4 without requiring advanced computational skills, extending the pool of users. Thus, a new extension to TOPAS, TOPAS-nBio, is under development to facilitate the configuration of track-structure simulations as well as water radiolysis simulations with Geant4-DNA for radiobiological studies. In this work, radiolysis simulations were implemented in TOPAS-nBio. Users may now easily add chemical species and their reactions, and set parameters including branching ratios, dissociation schemes, diffusion coefficients, and reaction rates. In addition, parameters for the chemical stage were re-evaluated and updated from those used by default in Geant4-DNA to improve the accuracy of chemical yields. Simulation results of time-dependent and LET-dependent primary yields Gx (chemical species per 100 eV deposited) produced at neutral pH and 25 °C by short track-segments of charged particles were compared to published measurements. The LET range was 0.05–230 keV µm‑1. The calculated Gx values for electrons satisfied the material balance equation within 0.3%, similar for protons albeit with long calculation time. A smaller geometry was used to speed up proton and alpha simulations, with an acceptable difference in the balance equation of 1.3%. Available experimental data of time-dependent G-values for agreed with simulated results within 7%  ±  8% over the entire time range; for over the full time range within 3%  ±  4% for H2O2 from 49%  ±  7% at earliest stages and 3%  ±  12% at saturation. For the LET-dependent Gx, the mean ratios to the experimental data were 1.11  ±  0.98, 1.21  ±  1.11, 1.05

  1. An Influence of Gas Explosions on Dynamic Responses of a Single Degree of Freedom Model

    Directory of Open Access Journals (Sweden)

    Ki-Yeob Kang

    2016-01-01

    Full Text Available Explosion risk analysis (ERA is widely used to derive the dimensioning of accidental loads for design purposes. Computational fluid dynamics (CFD simulations contribute a key part of an ERA and predict possible blast consequences in a hazardous area. Explosion pressures can vary based on the model geometry, the explosion intensity, and explosion scenarios. Dynamic responses of structures under these explosion loads are dependent on a blast wave profile with respect to the magnitude of pressure, duration, and impulse in both positive and negative phases. Understanding the relationship between explosion load profiles and dynamic responses of the target area is important to mitigate the risk of explosion and perform structural design optimization. In the present study, the results of more than 3,000 CFD simulations were considered, and 1.6 million output files were analyzed using a visual basic for applications (VBA tool developed to characterize representative loading shapes. Dynamic response of a structure was investigated in both time and frequency domains using the Fast Fourier Transform (FFT algorithm. In addition, the effects of the residual wave and loading velocity were studied in this paper.

  2. A two-phase model for aluminized explosives on the ballistic and brisance performance

    Science.gov (United States)

    Kim, Wuhyun; Gwak, Min-cheol; Lee, Young-hun; Yoh, Jack J.

    2018-02-01

    The performance of aluminized high explosives is considered by varying the aluminum (Al) mass fraction in a heterogeneous mixture model. Since the time scales of the characteristic induction and combustion of high explosives and Al particles differ, the process of energy release behind the leading detonation wave front occurs over an extended period of time. For simulating the performance of aluminized explosives with varying Al mass fraction, HMX (1,3,5,7-tetrahexmine-1,3,5,7-tetrazocane) is considered as a base explosive when formulating the multiphase conservation laws of mass, momentum, and energy exchanges between the HMX product gases and Al particles. In the current study, a two-phase model is utilized in order to determine the effects of the Al mass fraction in a condensed phase explosive. First, two types of confined rate stick tests are considered to investigate the detonation velocity and the acceleration ability, which refers to the radial expansion velocity of the confinement shell. The simulation results of the confined rate stick test are compared with the experimental data for the Al mass fraction range of 0%-25%, and the optimal Al mass fraction is provided, which is consistent with the experimental observations. Additionally, a series of plate dent test simulations are conducted, the results of which show the same tendency as those of the experimental tests with varying Al mass fractions.

  3. Chemistry {ampersand} Materials Science progress report summary of selected research and development topics, FY97

    Energy Technology Data Exchange (ETDEWEB)

    Newkirk, L.

    1997-12-01

    This report contains summaries of research performed in the Chemistry and Materials Science division. Topics include Metals and Ceramics, High Explosives, Organic Synthesis, Instrument Development, and other topics.

  4. Steam explosion triggering and efficiency studies

    International Nuclear Information System (INIS)

    Buxton, L.D.; Nelson, L.S.; Benedick, W.B.

    1979-01-01

    Laboratory experiments on the thermal interaction of simulated light water reactor (LWR) fuel melts and water are summarized. Their purpose was to investigate the possibility of steam explosions occurring for a range of hypothetical accident conditions. Pressure, temperature, hot liquid motion and cold liquid motion were monitored during the experiments

  5. Gas explosion in domestic buildings. The vented gas explosion[sub][/sub

    Directory of Open Access Journals (Sweden)

    Tadeusz Chyży

    2014-08-01

    Full Text Available In this paper, the basic information, related to the so-called vented gas explosion, has been presented. The vented explosion it is an explosion, during which the destruction of the weakest elements of the structure occurs. Through the resulting holes (decompressing surfaces can flow both combustion products and non-burned gas mixture. In consequence, reduction of the maximum explosion pressure[i] P[sub]red [/sub][/i] may be significant. Often, a gas explosion occurs inside residential buildings. In this case, natural vents are window and door openings.[b]Keywords[/b]: gas, explosion, combustion, explosion vents

  6. Nucleosynthesis in neutrino-driven, aspherical supernova explosion of a massive star

    International Nuclear Information System (INIS)

    Fujimoto, S.; Hashimoto, M.; Ono, M.; Kotake, K.; Ohnishi, N.

    2011-01-01

    We examine explosive nucleosynthesis of p-nuclei during a delayed neutrino-driven, aspherical supernova explosion aided by standing accretion shock instability, based on two-dimensional hydrodynamic simulations of the explosion of a 15M · star. We find that p-nuclei are mainly produced through γ-processes, and that the nuclei lighter than 92 Mo are abundantly synthesized in slightly neutron-rich bubbles with electron fractions of Y e ≤0.48. 94 Mo, 96 Ru, and 98 Ru, are underproduced compared with the solar system, as in the spherical model.

  7. Numerical simulation of the ionization effects of low- and high-altitude nuclear explosions

    International Nuclear Information System (INIS)

    Zhao Zhengyu; Wang Xiang

    2007-01-01

    Low-altitude and high-altitude nuclear explosions are sources of intensive additional ionization in ionosphere. In this paper, in terms of the ionization equilibrium equation system and the equation of energy deposition of radiation in atmosphere, and considering the influence of atmosphere, the temporal and spatial distribution of ionization effects caused by atmospheric nuclear detonation are investigated. The calculated results show that the maximum of additional free electron density produced by low-altitude nuclear explosion is greater than that by the high-altitude nuclear burst. As to the influence of instant nuclear radiation, there is obvious difference between the low-altitude and the high-altitude explosions. The influence range and the continuance time caused by delayed nuclear radiation is less for the low-altitude nuclear detonation than that for the high-altitude one. (authors)

  8. Advances in impact resistance testing for explosion-proof electrical equipment

    Directory of Open Access Journals (Sweden)

    Pasculescu Vlad Mihai

    2017-01-01

    Full Text Available The design, construction and exploitation of electrical equipment intended to be used in potentially explosive atmospheres presents a series of difficulties. Therefore, the approach of these phases requires special attention concerning technical, financial and occupational health and safety aspects. In order for them not to generate an ignition source for the explosive atmosphere, such equipment have to be subjected to a series of type tests aiming to decrease the explosion risk in technological installations which operate in potentially explosive atmospheres. Explosion protection being a concern of researchers and authorities worldwide, testing and certification of explosion-proof electrical equipment, required for their conformity assessment, are extremely important, taking into account the unexpected explosion hazard due to potentially explosive atmospheres, risk which has to be minimized in order to ensure the occupational health and safety of workers, for preventing material losses and for decreasing the environmental pollution. Besides others, one of the type tests, which shall be applied, for explosion-proof electrical equipment is the impact resistance test, described in detail in EN 60079 which specifies the general requirements for construction, testing and marking of electrical equipment and Ex components intended for use in explosive atmospheres. This paper presents an analysis on the requirements of the impact resistance test for explosion-proof electrical equipment and on the possibilities to improve this type of test, by making use of modern computer simulation tools based on finite element analysis, techniques which are widely used nowadays in the industry and for research purposes.

  9. Phase chemistry and radionuclide retention from simulated tank sludges

    International Nuclear Information System (INIS)

    KRUMHANSL, JAMES L.; LIU, J.; ARTHUR, SARA E.; HUTCHERSON, SHEILA K.; QIAN, MORRIS; ANDERSON, HOWARD L.

    2000-01-01

    Decommissioning high level nuclear waste tanks will leave small amounts of residual sludge clinging to the walls and floor of the structures. The permissible amount of material left in the tanks depends on the radionuclide release characteristics of the sludge. At present, no systematic process exists for assessing how much of the remaining inventory will migrate, and which radioisotopes will remain relatively fixed. Working with actual sludges is both dangerous and prohibitively expensive. Consequently, methods were developed for preparing sludge simulants and doping them with nonradioactive surrogates for several radionuclides and RCRA metals of concern in actual sludges. The phase chemistry of these mixes was found to be a reasonable match for the main phases in actual sludges. Preliminary surrogate release characteristics for these sludges were assessed by lowering the ionic strength and pH of the sludges in the manner that would occur if normal groundwater gained access to a decommissioned tank. Most of the Se, Cs and Tc in the sludges will be released into the first pulse of groundwater passing through the sludge. A significant fraction of the other surrogates will be retained indefinitely by the sludges. This prolonged sequestration results from a combination coprecipitated and sorbed into or onto relatively insoluble phases such as apatite, hydrous oxides of Fe, Al, Bi and rare earth oxides and phosphates. The coprecipitated fraction cannot be released until the host phase dissolves or recrystallizes. The sorbed fraction can be released by ion exchange processes as the pore fluid chemistry changes. However, these releases can be predicted based on a knowledge of the fluid composition and the surface chemistry of the solids. In this regard, the behavior of the hydrous iron oxide component of most sludges will probably play a dominant role for many cationic radionuclides while the hydrous aluminum oxides may be more important in governing anion releases

  10. Investigation of the shallow depth explosions

    International Nuclear Information System (INIS)

    Kamegai, M.

    1976-01-01

    An investigation of the nuclear explosions at shallow depth is made. A combination of an explosion code and an effects code proves to be an excellent tool for this study. A numerical simulation of ''Johnie Boy'' shows that the energy coupling to the air takes place in two stages; first by a rising mound, and then by a vented source. The thermal effects are examined for a 1 kt source at three depths of burial. The ''mushroom effect'' leaves a hot radiative plasma in the upper level and cold materials in the lower region of the debris. The temperature and the energy density of the debris can give an upper limit on the thermal output

  11. Explosion hazards of LPG-air mixtures in vented enclosure with obstacles.

    Science.gov (United States)

    Zhang, Qi; Wang, Yaxing; Lian, Zhen

    2017-07-15

    Numerical simulations were performed to study explosion characteristics of liquefied petroleum gas (LPG) explosion in enclosure with a vent. Unlike explosion overpressure and dynamic pressure, explosion temperature of the LPG-air mixture at a given concentration in a vented enclosure has very little variation with obstacle numbers for a given blockage ratio. For an enclosure without obstacle, explosion overpressures for the stoichiometric mixtures and the fuel-lean mixtures reach their maximum within the vent and that for fuel-rich mixture reaches its maximum beyond and near the vent. Dynamic pressures produced by an indoor LPG explosion reach their maximum always beyond the vent no matter obstacles are present or not in the enclosure. A LPG explosion in a vented enclosure with built-in obstacles is strong enough to make the brick and mortar wall with a thickness of 370mm damaged. If there is no obstacle in the enclosure, the lower explosion pressure of several kPa can not break the brick and mortar wall with a thickness of 370mm. For a LPG explosion produced in an enclosure with a vent, main hazards, within the vent, are overpressure and high temperature. However main hazards are dynamic pressure, blast wind, and high temperature beyond the vent. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. SEISMIC SIMULATIONS USING PARALLEL COMPUTING AND THREE-DIMENSIONAL EARTH MODELS TO IMPROVE NUCLEAR EXPLOSION PHENOMENOLOGY AND MONITORING

    Energy Technology Data Exchange (ETDEWEB)

    Rodgers, A; Matzel, E; Pasyanos, M; Petersson, A; Sjogreen, B; Bono, C; Vorobiev, O; Antoun, T; Walter, W; Myers, S; Lomov, I

    2008-07-07

    The development of accurate numerical methods to simulate wave propagation in three-dimensional (3D) earth models and advances in computational power offer exciting possibilities for modeling the motions excited by underground nuclear explosions. This presentation will describe recent work to use new numerical techniques and parallel computing to model earthquakes and underground explosions to improve understanding of the wave excitation at the source and path-propagation effects. Firstly, we are using the spectral element method (SEM, SPECFEM3D code of Komatitsch and Tromp, 2002) to model earthquakes and explosions at regional distances using available 3D models. SPECFEM3D simulates anelastic wave propagation in fully 3D earth models in spherical geometry with the ability to account for free surface topography, anisotropy, ellipticity, rotation and gravity. Results show in many cases that 3D models are able to reproduce features of the observed seismograms that arise from path-propagation effects (e.g. enhanced surface wave dispersion, refraction, amplitude variations from focusing and defocusing, tangential component energy from isotropic sources). We are currently investigating the ability of different 3D models to predict path-specific seismograms as a function of frequency. A number of models developed using a variety of methodologies are available for testing. These include the WENA/Unified model of Eurasia (e.g. Pasyanos et al 2004), the global CUB 2.0 model (Shapiro and Ritzwoller, 2002), the partitioned waveform model for the Mediterranean (van der Lee et al., 2007) and stochastic models of the Yellow Sea Korean Peninsula region (Pasyanos et al., 2006). Secondly, we are extending our Cartesian anelastic finite difference code (WPP of Nilsson et al., 2007) to model the effects of free-surface topography. WPP models anelastic wave propagation in fully 3D earth models using mesh refinement to increase computational speed and improve memory efficiency. Thirdly

  13. On the use of plant emitted volatile organic compounds for atmospheric chemistry simulation experiments

    Science.gov (United States)

    Kiendler-Scharr, A.; Hohaus, T.; Yu, Z.; Tillmann, R.; Kuhn, U.; Andres, S.; Kaminski, M.; Wegener, R.; Novelli, A.; Fuchs, H.; Wahner, A.

    2015-12-01

    Biogenic volatile organic compounds (BVOC) contribute to about 90% of the emitted VOC globally with isoprene being one of the most abundant BVOC (Guenther 2002). Intensive efforts in studying and understanding the impact of BVOC on atmospheric chemistry were undertaken in the recent years. However many uncertainties remain, e.g. field studies have shown that in wooded areas measured OH reactivity can often not be explained by measured BVOC and their oxidation products (e.g. Noelscher et al. 2012). This discrepancy may be explained by either a lack of understanding of BVOC sources or insufficient understanding of BVOC oxidation mechanisms. Plants emit a complex VOC mixture containing likely many compounds which have not yet been measured or identified (Goldstein and Galbally 2007). A lack of understanding BVOC sources limits bottom-up estimates of secondary products of BVOC oxidation such as SOA. Similarly, the widespread oversimplification of atmospheric chemistry in simulation experiments, using single compound or simple BVOC mixtures to study atmospheric chemistry processes limit our ability to assess air quality and climate impacts of BVOC. We will present applications of the new extension PLUS (PLant chamber Unit for Simulation) to our atmosphere simulation chamber SAPHIR. PLUS is used to produce representative BVOC mixtures from direct plant emissions. We will report on the performance and characterization of the newly developed chamber. As an exemplary application, trees typical of a Boreal forest environment were used to compare OH reactivity as directly measured by LIF to the OH reactivity calculated from BVOC measured by GC-MS and PTRMS. The comparison was performed for both, primary emissions of trees without any influence of oxidizing agents and using different oxidation schemes. For the monoterpene emitters investigated here, we show that discrepancies between measured and calculated total OH reactivity increase with increasing degree of oxidation

  14. Fluid-Structure Interaction Mechanisms for Close-In Explosions

    Directory of Open Access Journals (Sweden)

    Andrew B. Wardlaw Jr.

    2000-01-01

    Full Text Available This paper examines fluid-structure interaction for close-in internal and external underwater explosions. The resulting flow field is impacted by the interaction between the reflected explosion shock and the explosion bubble. This shock reflects off the bubble as an expansion that reduces the pressure level between the bubble and the target, inducing cavitation and its subsequent collapse that reloads the target. Computational examples of several close-in interaction cases are presented to document the occurrence of these mechanisms. By comparing deformable and rigid body simulations, it is shown that cavitation collapse can occur solely from the shock-bubble interaction without the benefit of target deformation. Addition of a deforming target lowers the flow field pressure, facilitates cavitation and cavitation collapse, as well as reducing the impulse of the initial shock loading.

  15. Thermal Radiation Effects on Thermal Explosion in Polydisperse Fuel Spray-Probabilistic Model

    Directory of Open Access Journals (Sweden)

    Ophir Navea

    2011-06-01

    Full Text Available We investigate the effect of thermal radiation on the dynamics of a thermal explosion of polydisperse fuel spray with a complete description of the chemistry via a single-step two-reactant model of general order. The polydisperse spray is modeled using a Probability Density Function (PDF. The thermal radiation energy exchange between the evaporation surface of the fuel droplets and the burning gas is described using the Marshak boundary conditions. An explicit expression of the critical condition for thermal explosion limit is derived analytically and represents a generalization of the critical parameter of the classical Semenov theory. Because we investigated the model in the range where the temperature is very high, the effect of the thermal radiation is significant.

  16. Safety demonstration tests of air-ventilation system for the postulated explosive burning in a cell of fuel-reprocessing plant

    International Nuclear Information System (INIS)

    Takada, Junichi; Suzuki, Motoe; Tukamoto, Michio; Koike, Tadao; Nishio, Gunji

    1995-03-01

    Safety demonstration tests of an explosive burning in a cell in the reprocessing plant has been carried out in JAERI under the auspices of the Science and Technology Agency, to evaluate the safety of an air-ventilation system during the hypothetical explosion. The postulated explosive burning of organic solvent mixed with nitric acid was simulated by solid explosives. The demonstration test was performed using an industrial scale experimental facility simulating to the ventilation system of the large scale reprocessing plant in JAPAN. Propagations of pressure, temperature, and gas velocity through cells and ducts in the ventilation system were measured during the explosive burning under deflagration. Experimental data in this report can be used to evaluate the transport phenomena of radioactive materials in the ventilation system during the explosion, and also to verify computer code CELVA for the safety analysis of ventilation system in the event of explosion accidents. (author)

  17. General phenomenology of underground nuclear explosions; Phenomenologie generale des explosions nucleaires souterraines

    Energy Technology Data Exchange (ETDEWEB)

    Derlich, S; Supiot, F [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes

    1969-07-01

    An essentially qualitatively description is given of the phenomena related to underground nuclear explosions (explosion of a single unit, of several units in line, and simultaneous explosions). In the first chapter are described the phenomena which are common to contained explosions and to explosions forming craters (formation and propagation of a shock-wave causing the vaporization, the fusion and the fracturing of the medium). The second chapter describes the phenomena related to contained explosions (formation of a cavity with a chimney). The third chapter is devoted to the phenomenology of test explosions which form a crater; it describes in particular the mechanism of formation and the different types of craters as a function of the depth of the explosion and of the nature of the ground. The aerial phenomena connected with explosions which form a crater: shock wave in the air and focussing at a large distance, and dust clouds, are also dealt with. (authors) [French] On donne une description essentiellement qualitative des phenomenes lies aux explosions nucleaires souterraines (explosion d'un seul engin, d'engins en ligne et explosions simultanees). Dans un premier chapitre sont decrits les phenomenes communs aux explosions contenues et aux explosions formant un cratere (formation et propagation d'une onde de choc provoquant la vaporisation, la fusion et la fracturation du milieu). Le deuxieme chapitre decrit les phenomenes lies aux tirs contenus (formation d'une cavite et d'une cheminee). Le troisieme chapitre est consacre a la phenomenologie des tirs formant un cratere et decrit notamment le mecanisme de formation et les differents types de crateres en fonction de la profondeur d'explosion et de la nature du terrain. Les phenomenes aeriens lies aux explosions formant un cratere: onde de pression aerienne et focalisation a grande distance, nuages de poussieres, sont egalement abordes. (auteurs)

  18. Neutron albedo effects of underground nuclear explosion

    International Nuclear Information System (INIS)

    Yang Bo; Ying Yangjun; Li Jinhong; Bai Yun

    2013-01-01

    The neutron field distribution is affected by the surrounding medium in the underground nuclear explosion. It will influence the radiation chemical diagnosis. By Monte Carlo simulation, the fuel burnup induced by device and neutron albedo was calculated. The analysis method of albedo effect on radiation chemical diagnosis result under special environment was proposed. Neutron albedo should be considered when capture reaction burnup fraction is used, and then correct analysis can be carried out on the nuclear device.The neutron field distribution is affected by the surrounding medium in the underground nuclear explosion. It will influence the radiation chemical diagnosis. By Monte Carlo simulation, the fuel burnup induced by device and neutron albedo was calculated. The analysis method of albedo effect on radiation chemical diagnosis result under special environment was proposed. Neutron albedo should be considered when capture reaction burnup fraction is used, and then correct analysis can be carried out on the nuclear device. (authors)

  19. Seismic coupling of nuclear explosions. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Larson, D B [ed.; Defense Advanced Research Projects Agency, Arlington, VA (United States)

    1989-12-31

    The new Giant Magnet Experimental Facility employing digital recording of explosion induced motion has been constructed and successfully tested. Particle velocity and piezoresistance gage responses can be measured simultaneously thus providing the capability for determining the multi-component stress-strain history in the test material. This capability provides the information necessary for validation of computer models used in simulation of nuclear underground testing, chemical explosion testing, dynamic structural response, earth penetration response, and etc. This report discusses fully coupled and cavity decoupled explosions of the same energy (0.622 kJ) were carried out as experiments to study wave propagation and attenuation in polymethylmethacrylate (PMMA). These experiments produced particle velocity time histories at strains from 2 {times} 10{sup {minus}3} to as low as 5.8 {times} 10{sup {minus}6}. Other experiments in PMMA, reported recently by Stout and Larson{sup 8} provide additional particle velocity data to strains of 10{sup {minus}1}.

  20. Using Transport Diagnostics to Understand Chemistry Climate Model Ozone Simulations

    Science.gov (United States)

    Strahan, S. E.; Douglass, A. R.; Stolarski, R. S.; Akiyoshi, H.; Bekki, S.; Braesicke, P.; Butchart, N.; Chipperfield, M. P.; Cugnet, D.; Dhomse, S.; hide

    2010-01-01

    We demonstrate how observations of N2O and mean age in the tropical and midlatitude lower stratosphere (LS) can be used to identify realistic transport in models. The results are applied to 15 Chemistry Climate Models (CCMs) participating in the 2010 WMO assessment. Comparison of the observed and simulated N2O/mean age relationship identifies models with fast or slow circulations and reveals details of model ascent and tropical isolation. The use of this process-oriented N2O/mean age diagnostic identifies models with compensating transport deficiencies that produce fortuitous agreement with mean age. We compare the diagnosed model transport behavior with a model's ability to produce realistic LS O3 profiles in the tropics and midlatitudes. Models with the greatest tropical transport problems show the poorest agreement with observations. Models with the most realistic LS transport agree more closely with LS observations and each other. We incorporate the results of the chemistry evaluations in the SPARC CCMVal Report (2010) to explain the range of CCM predictions for the return-to-1980 dates for global (60 S-60 N) and Antarctic column ozone. Later (earlier) Antarctic return dates are generally correlated to higher (lower) vortex Cl(sub y) levels in the LS, and vortex Cl(sub y) is generally correlated with the model's circulation although model Cl(sub y) chemistry or Cl(sub y) conservation can have a significant effect. In both regions, models that have good LS transport produce a smaller range of predictions for the return-to-1980 ozone values. This study suggests that the current range of predicted return dates is unnecessarily large due to identifiable model transport deficiencies.

  1. Explosive synchronization coexists with classical synchronization in the Kuramoto model

    Energy Technology Data Exchange (ETDEWEB)

    Danziger, Michael M., E-mail: michael.danziger@biu.ac.il; Havlin, Shlomo [Department of Physics, Bar-Ilan University, Ramat Gan (Israel); Moskalenko, Olga I.; Kurkin, Semen A. [Faculty of Nonlinear Processes, Saratov State University, Astrakhanskaya, 83, Saratov 410012 (Russian Federation); Saratov State Technical University, Politehnicheskaya, 77, Saratov 410054 (Russian Federation); Zhang, Xiyun [Department of Physics, East China Normal University, Shanghai 200062 (China); Boccaletti, Stefano [CNR-Institute of Complex Systems, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Florence (Italy); The Italian Embassy in Israel, 25 Hamered Street, 68125 Tel Aviv (Israel)

    2016-06-15

    Explosive synchronization has recently been reported in a system of adaptively coupled Kuramoto oscillators, without any conditions on the frequency or degree of the nodes. Here, we find that, in fact, the explosive phase coexists with the standard phase of the Kuramoto oscillators. We determine this by extending the mean-field theory of adaptively coupled oscillators with full coupling to the case with partial coupling of a fraction f. This analysis shows that a metastable region exists for all finite values of f > 0, and therefore explosive synchronization is expected for any perturbation of adaptively coupling added to the standard Kuramoto model. We verify this theory with GPU-accelerated simulations on very large networks (N ∼ 10{sup 6}) and find that, in fact, an explosive transition with hysteresis is observed for all finite couplings. By demonstrating that explosive transitions coexist with standard transitions in the limit of f → 0, we show that this behavior is far more likely to occur naturally than was previously believed.

  2. Step-by-Step Simulation of Radiation of Radiation Chemistry Using Green Functions for Diffusion-Influenced Reactions

    Science.gov (United States)

    Plante, Ianik; Cucinotta, Francis A.

    2011-01-01

    The irradiation of biological systems leads to the formation of radiolytic species such as H(raised dot), (raised dot)OH, H2, H2O2, e(sup -)(sub aq), etc.[1]. These species react with neighboring molecules, which result in damage in biological molecules such as DNA. Radiation chemistry is there for every important to understand the radiobiological consequences of radiation[2]. In this work, we discuss an approach based on the exact Green Functions for diffusion-influenced reactions which may be used to simulate radiation chemistry and eventually extended to study more complex systems, including DNA.

  3. Understanding vented gas explosions

    Energy Technology Data Exchange (ETDEWEB)

    Lautkaski, R. [VTT Energy, Espoo (Finland). Energy Systems

    1997-12-31

    The report is an introduction to vented gas explosions for nonspecialists, particularly designers of plants for flammable gases and liquids. The phenomena leading to pressure generation in vented gas explosions in empty and congested rooms are reviewed. The four peak model of vented gas explosions is presented with simple methods to predict the values of the individual peaks. Experimental data on the external explosion of dust and gas explosions is discussed. The empirical equation relating the internal and external peak pressures in vented dust explosions is shown to be valid for gas explosion tests in 30 m{sup 3} and 550 m{sup 3} chambers. However, the difficulty of predicting the internal peak pressure in large chambers remains. Methods of explosion relief panel design and principles of vent and equipment layout to reduce explosion overpressures are reviewed. (orig.) 65 refs.

  4. Understanding vented gas explosions

    Energy Technology Data Exchange (ETDEWEB)

    Lautkaski, R [VTT Energy, Espoo (Finland). Energy Systems

    1998-12-31

    The report is an introduction to vented gas explosions for nonspecialists, particularly designers of plants for flammable gases and liquids. The phenomena leading to pressure generation in vented gas explosions in empty and congested rooms are reviewed. The four peak model of vented gas explosions is presented with simple methods to predict the values of the individual peaks. Experimental data on the external explosion of dust and gas explosions is discussed. The empirical equation relating the internal and external peak pressures in vented dust explosions is shown to be valid for gas explosion tests in 30 m{sup 3} and 550 m{sup 3} chambers. However, the difficulty of predicting the internal peak pressure in large chambers remains. Methods of explosion relief panel design and principles of vent and equipment layout to reduce explosion overpressures are reviewed. (orig.) 65 refs.

  5. Computational Materials Science and Chemistry: Accelerating Discovery and Innovation through Simulation-Based Engineering and Science

    Energy Technology Data Exchange (ETDEWEB)

    Crabtree, George [Argonne National Lab. (ANL), Argonne, IL (United States); Glotzer, Sharon [University of Michigan; McCurdy, Bill [University of California Davis; Roberto, Jim [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2010-07-26

    This report is based on a SC Workshop on Computational Materials Science and Chemistry for Innovation on July 26-27, 2010, to assess the potential of state-of-the-art computer simulations to accelerate understanding and discovery in materials science and chemistry, with a focus on potential impacts in energy technologies and innovation. The urgent demand for new energy technologies has greatly exceeded the capabilities of today's materials and chemical processes. To convert sunlight to fuel, efficiently store energy, or enable a new generation of energy production and utilization technologies requires the development of new materials and processes of unprecedented functionality and performance. New materials and processes are critical pacing elements for progress in advanced energy systems and virtually all industrial technologies. Over the past two decades, the United States has developed and deployed the world's most powerful collection of tools for the synthesis, processing, characterization, and simulation and modeling of materials and chemical systems at the nanoscale, dimensions of a few atoms to a few hundred atoms across. These tools, which include world-leading x-ray and neutron sources, nanoscale science facilities, and high-performance computers, provide an unprecedented view of the atomic-scale structure and dynamics of materials and the molecular-scale basis of chemical processes. For the first time in history, we are able to synthesize, characterize, and model materials and chemical behavior at the length scale where this behavior is controlled. This ability is transformational for the discovery process and, as a result, confers a significant competitive advantage. Perhaps the most spectacular increase in capability has been demonstrated in high performance computing. Over the past decade, computational power has increased by a factor of a million due to advances in hardware and software. This rate of improvement, which shows no sign of

  6. Algorithm describing pressure distribution of non-contact TNT explosion

    Directory of Open Access Journals (Sweden)

    Radosław Kiciński

    2014-12-01

    Full Text Available [b]Abstract[/b]. The aim of this study is to develop a computational algorithm, describing the shock wave pressure distribution in the space induced by non-contact TNT explosion. The procedure describes pressure distribution on a damp surface of the hull. Simulations have been carried out using Abaqus/CAE. The study also shows the pressure waveform descriptions provided by various authors and presents them in charts. The formulated conclusions convince efficiency of the algorithm application.[b]Keywords:[/b] Underwater explosion, shock wave, CAE, TNT, Kobben class submarine

  7. Explosive material treatment in particular the explosive compaction of powders

    International Nuclear Information System (INIS)

    Pruemmer, R.

    1985-01-01

    The constructive use of explosives in the last decades has led to new procedures in manufacturing techniques. The most important of these are explosive forming and cladding, the latter especially for the production of compound materials. The method of explosive compaction has the highest potential for further innovation. Almost theoretical densities are achievable in the green compacts as the pressure released by detonating explosives are very high. Also, the production of new conditions of materials (metastable high pressure phases) is possible. (orig.) [de

  8. Explosive attractor solutions to a universal cubic delay equation

    Science.gov (United States)

    Sanz-Orozco, D.; Berk, H. L.

    2017-05-01

    New explosive attractor solutions have been found in a universal cubic delay equation that has been studied in both the plasma and the fluid mechanics literature. Through computational simulations and analytic approximations, it is found that the oscillatory component of the explosive mode amplitude solutions are described through multi-frequency Fourier expansions with respect to a pseudo-time variable. The spectral dependence of these solutions as a function of a system parameter, ϕ , is studied. The mode amplitude that is described in the explosive regime has two main features: a well-known envelope ( t 0 - t ) - 5 / 2 , with t0 the blow-up time of the amplitude, and a spectrum of discrete oscillations with ever-increasing frequencies, which may give experimental information about the properties of a system's equilibrium.

  9. Considerations for the independent reaction times and step-by-step methods for radiation chemistry simulations

    Science.gov (United States)

    Plante, Ianik; Devroye, Luc

    2017-10-01

    Ionizing radiation interacts with the water molecules of the tissues mostly by ionizations and excitations, which result in the formation of the radiation track structure and the creation of radiolytic species such as H.,.OH, H2, H2O2, and e-aq. After their creation, these species diffuse and may chemically react with the neighboring species and with the molecules of the medium. Therefore radiation chemistry is of great importance in radiation biology. As the chemical species are not distributed homogeneously, the use of conventional models of homogeneous reactions cannot completely describe the reaction kinetics of the particles. Actually, many simulations of radiation chemistry are done using the Independent Reaction Time (IRT) method, which is a very fast technique to calculate radiochemical yields but which do not calculate the positions of the radiolytic species as a function of time. Step-by-step (SBS) methods, which are able to provide such information, have been used only sparsely because these are time-consuming in terms of calculation. Recent improvements in computer performance now allow the regular use of the SBS method in radiation chemistry. The SBS and IRT methods are both based on the Green's functions of the diffusion equation (GFDE). In this paper, several sampling algorithms of the GFDE and for the IRT method are presented. We show that the IRT and SBS methods are exactly equivalent for 2-particles systems for diffusion and partially diffusion-controlled reactions between non-interacting particles. We also show that the results obtained with the SBS simulation method with periodic boundary conditions are in agreement with the predictions by classical reaction kinetics theory, which is an important step towards using this method for modelling of biochemical networks and metabolic pathways involved in oxidative stress. Finally, the first simulation results obtained with the code RITRACKS (Relativistic Ion Tracks) are presented.

  10. Optimizing qubit resources for quantum chemistry simulations in second quantization on a quantum computer

    International Nuclear Information System (INIS)

    Moll, Nikolaj; Fuhrer, Andreas; Staar, Peter; Tavernelli, Ivano

    2016-01-01

    Quantum chemistry simulations on a quantum computer suffer from the overhead needed for encoding the Fermionic problem in a system of qubits. By exploiting the block diagonality of a Fermionic Hamiltonian, we show that the number of required qubits can be reduced while the number of terms in the Hamiltonian will increase. All operations for this reduction can be performed in operator space. The scheme is conceived as a pre-computational step that would be performed prior to the actual quantum simulation. We apply this scheme to reduce the number of qubits necessary to simulate both the Hamiltonian of the two-site Fermi–Hubbard model and the hydrogen molecule. Both quantum systems can then be simulated with a two-qubit quantum computer. Despite the increase in the number of Hamiltonian terms, the scheme still remains a useful tool to reduce the dimensionality of specific quantum systems for quantum simulators with a limited number of resources. (paper)

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

    Energy Technology Data Exchange (ETDEWEB)

    Orlando, S.; Miceli, M.; Pumo, M. L.; Bocchino, F., E-mail: orlando@astropa.inaf.it [INAF—Osservatorio Astronomico di Palermo “G.S. Vaiana,” Piazza del Parlamento 1, I-90134 Palermo (Italy)

    2016-05-01

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

  12. Reactive simulation of the chemistry behind the condensed-phase ignition of RDX from hot spots.

    Science.gov (United States)

    Joshi, Kaushik L; Chaudhuri, Santanu

    2015-07-28

    Chemical events that lead to thermal initiation and spontaneous ignition of the high-pressure phase of RDX are presented using reactive molecular dynamics simulations. In order to initiate the chemistry behind thermal ignition, approximately 5% of RDX crystal is subjected to a constant temperature thermal pulse for various time durations to create a hot spot. After application of the thermal pulse, the ensuing chemical evolution of the system is monitored using reactive molecular dynamics under adiabatic conditions. Thermal pulses lasting longer than certain time durations lead to the spontaneous ignition of RDX after an incubation period. For cases where the ignition is observed, the incubation period is dominated by intermolecular and intramolecular hydrogen transfer reactions. Contrary to the widely accepted unimolecular models of initiation chemistry, N-N bond dissociations that produce NO2 species are suppressed in the condensed phase. The gradual temperature and pressure increase in the incubation period is accompanied by the accumulation of short-lived, heavier polyradicals. The polyradicals contain intact triazine rings from the RDX molecules. At certain temperatures and pressures, the polyradicals undergo ring-opening reactions, which fuel a series of rapid exothermic chemical reactions leading to a thermal runaway regime with stable gas-products such as N2, H2O and CO2. The evolution of the RDX crystal throughout the thermal initiation, incubation and thermal runaway phases observed in the reactive simulations contains a rich diversity of condensed-phase chemistry of nitramines under high-temperature/pressure conditions.

  13. Computational chemistry

    Science.gov (United States)

    Arnold, J. O.

    1987-01-01

    With the advent of supercomputers, modern computational chemistry algorithms and codes, a powerful tool was created to help fill NASA's continuing need for information on the properties of matter in hostile or unusual environments. Computational resources provided under the National Aerodynamics Simulator (NAS) program were a cornerstone for recent advancements in this field. Properties of gases, materials, and their interactions can be determined from solutions of the governing equations. In the case of gases, for example, radiative transition probabilites per particle, bond-dissociation energies, and rates of simple chemical reactions can be determined computationally as reliably as from experiment. The data are proving to be quite valuable in providing inputs to real-gas flow simulation codes used to compute aerothermodynamic loads on NASA's aeroassist orbital transfer vehicles and a host of problems related to the National Aerospace Plane Program. Although more approximate, similar solutions can be obtained for ensembles of atoms simulating small particles of materials with and without the presence of gases. Computational chemistry has application in studying catalysis, properties of polymers, all of interest to various NASA missions, including those previously mentioned. In addition to discussing these applications of computational chemistry within NASA, the governing equations and the need for supercomputers for their solution is outlined.

  14. 75 FR 1085 - Commerce in Explosives; List of Explosive Materials (2009R-18T)

    Science.gov (United States)

    2010-01-08

    ... sensitive slurry and water gel explosives. Blasting caps. Blasting gelatin. Blasting powder. BTNEC [bis.... Explosive conitrates. Explosive gelatins. Explosive liquids. Explosive mixtures containing oxygen-releasing... powder. Fulminate of mercury. Fulminate of silver. Fulminating gold. Fulminating mercury. Fulminating...

  15. 75 FR 70291 - Commerce in Explosives; List of Explosive Materials (2010R-27T)

    Science.gov (United States)

    2010-11-17

    ..., including non-cap sensitive slurry and water gel explosives. Blasting caps. Blasting gelatin. Blasting.... Explosive conitrates. Explosive gelatins. Explosive liquids. Explosive mixtures containing oxygen-releasing... powder. Fulminate of mercury. Fulminate of silver. Fulminating gold. Fulminating mercury. Fulminating...

  16. Sensitivity of numerical dispersion modeling to explosive source parameters

    International Nuclear Information System (INIS)

    Baskett, R.L.; Cederwall, R.T.

    1991-01-01

    The calculation of downwind concentrations from non-traditional sources, such as explosions, provides unique challenges to dispersion models. The US Department of Energy has assigned the Atmospheric Release Advisory Capability (ARAC) at the Lawrence Livermore National Laboratory (LLNL) the task of estimating the impact of accidental radiological releases to the atmosphere anywhere in the world. Our experience includes responses to over 25 incidents in the past 16 years, and about 150 exercises a year. Examples of responses to explosive accidents include the 1980 Titan 2 missile fuel explosion near Damascus, Arkansas and the hydrogen gas explosion in the 1986 Chernobyl nuclear power plant accident. Based on judgment and experience, we frequently estimate the source geometry and the amount of toxic material aerosolized as well as its particle size distribution. To expedite our real-time response, we developed some automated algorithms and default assumptions about several potential sources. It is useful to know how well these algorithms perform against real-world measurements and how sensitive our dispersion model is to the potential range of input values. In this paper we present the algorithms we use to simulate explosive events, compare these methods with limited field data measurements, and analyze their sensitivity to input parameters. 14 refs., 7 figs., 2 tabs

  17. The Use of Nuclear Explosives To Disrupt or Divert Asteroids

    Energy Technology Data Exchange (ETDEWEB)

    Dearborn, D S; Patenaude, S; Managan, R A

    2007-02-20

    Nuclear explosives are a mature technology with well-characterized effects. Proposed utilizations include a near asteroid burst to ablate surface material and nudge the body to a safer orbit, or a direct sub-surface burst to fragment the body. For this latter method, previous estimates suggest that for times as short as 1000 days, over 99.999% of the material is diverted, and no longer impacts the Earth, a huge mitigation factor. To better understand these possibilities, we have used a multidimensional radiation/hydrodynamics code to simulate sub-surface and above surface bursts on an inhomogeneous, 1 km diameter body with an average density of 2 g/cc. The body, or fragments (up to 750,000) are then tracked along 4 representative orbits to determine the level of mitigation achieved. While our code has been well tested in simulations on terrestrial structures, the greatest uncertainty in these results lies in the input. These results, particularly the effort to nudge a body into a different orbit, are dependant on NEO material properties, like the dissipation of unconsolidated material in a low gravity environment, as well as the details on an individual body's structure. This problem exists in simulating the effect of any mitigation technology. In addition to providing an greater understanding of the results of applying nuclear explosives to NEO-like bodies, these simulations suggest what must be learned about these bodies to improve the predictive capabilities. Finally, we will comment on some of the popular misinformation abounding about the utility of nuclear explosives.

  18. Structure-based classification and ontology in chemistry

    Directory of Open Access Journals (Sweden)

    Hastings Janna

    2012-04-01

    Full Text Available Abstract Background Recent years have seen an explosion in the availability of data in the chemistry domain. With this information explosion, however, retrieving relevant results from the available information, and organising those results, become even harder problems. Computational processing is essential to filter and organise the available resources so as to better facilitate the work of scientists. Ontologies encode expert domain knowledge in a hierarchically organised machine-processable format. One such ontology for the chemical domain is ChEBI. ChEBI provides a classification of chemicals based on their structural features and a role or activity-based classification. An example of a structure-based class is 'pentacyclic compound' (compounds containing five-ring structures, while an example of a role-based class is 'analgesic', since many different chemicals can act as analgesics without sharing structural features. Structure-based classification in chemistry exploits elegant regularities and symmetries in the underlying chemical domain. As yet, there has been neither a systematic analysis of the types of structural classification in use in chemistry nor a comparison to the capabilities of available technologies. Results We analyze the different categories of structural classes in chemistry, presenting a list of patterns for features found in class definitions. We compare these patterns of class definition to tools which allow for automation of hierarchy construction within cheminformatics and within logic-based ontology technology, going into detail in the latter case with respect to the expressive capabilities of the Web Ontology Language and recent extensions for modelling structured objects. Finally we discuss the relationships and interactions between cheminformatics approaches and logic-based approaches. Conclusion Systems that perform intelligent reasoning tasks on chemistry data require a diverse set of underlying computational

  19. Preliminary Analysis of Ex-Vessel Steam Explosion using TEXAS-V code for APR1400

    International Nuclear Information System (INIS)

    Song, Sung Chu; Lee, Jung Jae; Cho, Yong Jin; Hwang, Taesuk

    2013-01-01

    The purpose of this study is to explore input development and the audit calculation using TEXAS-V code for ex-vessel steam explosion for a flooded reactor cavity of APR1400. TEXAS computational models are one of the simplified tools for simulations of fuel-coolant interaction during mixing, triggering and explosion phase. The models of TEXAS code were validated by performing the fundamental experimental investigation in the KROTOS facility at JRC, Ispra. The experiments such as KROTOS and FARO experiment are aimed at providing benchmark data to examine the effect of fuel-coolant initial conditions and mixing on explosion energetics with alumina and prototypical core material. TEXAS-V code used in this study was to analyze and predict the ex-vessel steam explosion for a reactor scale. The input deck to simulate the flooded reactor cavity of APR1400 is developed and base case calculation is performed. This study will provide a base for further study. The code will be of use for the evaluation and sensitivity study of ex-vessel steam explosion for ERVC strategy in the future studies. Analysis result of this study is similar to the result of other study. Through this study, it is found that TEXAS-V could be the used as a tool for predicting the steam explosion load on a reactor scale, as fast running computer code. In addition, TEXAS-V code could be to evaluate the impact of various uncertainties, which are not clearly understood yet, to provide a conservative envelope for the steam explosion

  20. Preliminary Analysis of Ex-Vessel Steam Explosion using TEXAS-V code for APR1400

    Energy Technology Data Exchange (ETDEWEB)

    Song, Sung Chu; Lee, Jung Jae; Cho, Yong Jin; Hwang, Taesuk [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2013-10-15

    The purpose of this study is to explore input development and the audit calculation using TEXAS-V code for ex-vessel steam explosion for a flooded reactor cavity of APR1400. TEXAS computational models are one of the simplified tools for simulations of fuel-coolant interaction during mixing, triggering and explosion phase. The models of TEXAS code were validated by performing the fundamental experimental investigation in the KROTOS facility at JRC, Ispra. The experiments such as KROTOS and FARO experiment are aimed at providing benchmark data to examine the effect of fuel-coolant initial conditions and mixing on explosion energetics with alumina and prototypical core material. TEXAS-V code used in this study was to analyze and predict the ex-vessel steam explosion for a reactor scale. The input deck to simulate the flooded reactor cavity of APR1400 is developed and base case calculation is performed. This study will provide a base for further study. The code will be of use for the evaluation and sensitivity study of ex-vessel steam explosion for ERVC strategy in the future studies. Analysis result of this study is similar to the result of other study. Through this study, it is found that TEXAS-V could be the used as a tool for predicting the steam explosion load on a reactor scale, as fast running computer code. In addition, TEXAS-V code could be to evaluate the impact of various uncertainties, which are not clearly understood yet, to provide a conservative envelope for the steam explosion.

  1. Steam explosions of molten iron oxide drops: easier initiation at small pressurizations

    International Nuclear Information System (INIS)

    Nelson, L.S.; Duda, P.M.

    1982-01-01

    Steam explosions caused by hot molten materials contacting liquid water following a possible light water nuclear reactor core overheat have been investigated by releasing single drops of a core melt simulant, molten iron oxide, into liquid water. Small steam explosions were triggered shortly afterwards by applying a pressure pulse to the water. The threshold peak pulse level above which an explosion always occurs was studied at ambient pressures between 0.083 and 1.12 MPa. It was found that the threshold decreased to a minimum in the range 0.2 - 0.8 MPa and then increased again. The effect of easier initiation as ambient pressure increases may have an important role in the triggering and propagation of a large scale steam explosion through a coarsely premixed dispersion of melt in water. (U.K.)

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

    Science.gov (United States)

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

    2018-01-01

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

  3. Analysis of ex-vessel steam explosion with MC3D

    International Nuclear Information System (INIS)

    Leskovar, M.; Mavko, B.

    2007-01-01

    An ex-vessel steam explosion may occur when, during a severe reactor accident, the reactor vessel fails and the molten core pours into the water in the reactor cavity. A steam explosion is a fuel coolant interaction process where the heat transfer from the melt to water is so intense and rapid that the timescale for heat transfer is shorter than the timescale for pressure relief. This can lead to the formation of shock waves and production of missiles that may endanger surrounding structures. A strong enough steam explosion in a nuclear power plant could jeopardize the containment integrity and so lead to a direct release of radioactive material to the environment. In the paper, different scenarios of ex-vessel steam explosions in a typical pressurized water reactor cavity are analyzed with the code MC3D, which was developed for the simulation of fuel-coolant interactions. A comprehensive parametric study was performed varying the location of the melt release (central, left and right side melt pour), the cavity water subcooling, the primary system overpressure at vessel failure and the triggering time for explosion calculations. The main purpose of the study was to determine the most challenging ex-vessel steam explosion cases in a typical pressurized water reactor and to estimate the expected pressure loadings on the cavity walls. The performed analysis shows that for some ex-vessel steam explosion scenarios significantly higher pressure loads are predicted than obtained in the OECD programme SERENA Phase 1. (author)

  4. Metallic glass coating on metals plate by adjusted explosive welding technique

    International Nuclear Information System (INIS)

    Liu, W.D.; Liu, K.X.; Chen, Q.Y.; Wang, J.T.; Yan, H.H.; Li, X.J.

    2009-01-01

    Using an adjusted explosive welding technique, an aluminum plate has been coated by a Fe-based metallic glass foil in this work. Scanning electronic micrographs reveal a defect-free metallurgical bonding between the Fe-based metallic glass foil and the aluminum plate. Experimental evidence indicates that the Fe-based metallic glass foil almost retains its amorphous state and mechanical properties after the explosive welding process. Additionally, the detailed explosive welding process has been simulated by a self-developed hydro-code and the bonding mechanism has been investigated by numerical analysis. The successful welding between the Fe-based metallic glass foil and the aluminum plate provides a new way to obtain amorphous coating on general metal substrates.

  5. The Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP): Overview and Description of Models, Simulations and Climate Diagnostics

    Science.gov (United States)

    Lamarque, J.-F.; Shindell, D. T.; Naik, V.; Plummer, D.; Josse, B.; Righi, M.; Rumbold, S. T.; Schulz, M.; Skeie, R. B.; Strode, S.; hide

    2013-01-01

    The Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) consists of a series of time slice experiments targeting the long-term changes in atmospheric composition between 1850 and 2100, with the goal of documenting composition changes and the associated radiative forcing. In this overview paper, we introduce the ACCMIP activity, the various simulations performed (with a requested set of 14) and the associated model output. The 16 ACCMIP models have a wide range of horizontal and vertical resolutions, vertical extent, chemistry schemes and interaction with radiation and clouds. While anthropogenic and biomass burning emissions were specified for all time slices in the ACCMIP protocol, it is found that the natural emissions are responsible for a significant range across models, mostly in the case of ozone precursors. The analysis of selected present-day climate diagnostics (precipitation, temperature, specific humidity and zonal wind) reveals biases consistent with state-of-the-art climate models. The model-to- model comparison of changes in temperature, specific humidity and zonal wind between 1850 and 2000 and between 2000 and 2100 indicates mostly consistent results. However, models that are clear outliers are different enough from the other models to significantly affect their simulation of atmospheric chemistry.

  6. The use of triangle diagram in the detection of explosive and illicit drugs

    Science.gov (United States)

    Sudac, Davorin; Baricevic, Martina; Obhodas, Jasmina; Franulovic, Andrej; Valkovic, Vladivoj

    2010-04-01

    A tagged neutron inspection system has been used for the detection of explosive and illicite drugs. Simulant of the RDX explosive was measured in different environments and its gamma ray spectra were compared with the gamma ray spectra of benign materials like paper, sugar and rise. "Fingerprint" of the RDX simulant was found by detecting the nitrogen as well as by making the triangle plot which coordinates show the carbon and oxygen content and density. Density was obtained by measuring the intensity of the transmited tagged neutrons. Hence, the presence of the simulant can be confirmed by using two different methods. The possibility of using the triangle plot for detection of illicit drugs like heroin, cocain and marihuana is also discused.

  7. Liquid explosives

    CERN Document Server

    Liu, Jiping

    2015-01-01

    The book drawing on the author's nearly half a century of energetic materials research experience intends to systematically review the global researches on liquid explosives. The book focuses on the study of the conception, explosion mechanism, properties and preparation of liquid explosives. It provides a combination of theoretical knowledge and practical examples in a reader-friendly style. The book is likely to be interest of university researchers and graduate students in the fields of energetic materials, blasting engineering and mining.

  8. Approximating the r-process on earth with thermonuclear explosions

    International Nuclear Information System (INIS)

    Becker, S.A.

    1992-01-01

    The astrophysical r-process can be approximately simulated in certain types of thermonuclear explosions. Between 1952 and 1969 twenty-three nuclear tests were fielded by the United States which had as one of their objectives the production of heavy transuranic elements. Of these tests, fifteen were at least partially successful. Some of these shots were conducted under the project Plowshare Peaceful Nuclear Explosion Program as scientific research experiments. A review of the program, target nuclei used, and heavy element yields achieved, will be presented as well as discussion of plans for a new experiment in a future nuclear test

  9. Silver salt of 4,6-diazido-N-nitro-1,3,5-triazine-2-amine - characterization of this primary explosive

    Czech Academy of Sciences Publication Activity Database

    Musil, T.; Matyáš, R.; Vala, R.; Růžička, A.; Vlček, Milan

    2014-01-01

    Roč. 39, č. 2 (2014), s. 251-259 ISSN 0721-3115 Institutional support: RVO:61389013 Keywords : primary explosive * AgDANT * silver salt of 4,6-diazido-N-nitro-1,3,5-triazine-2-amine Subject RIV: CC - Organic Chemistry Impact factor: 1.604, year: 2014

  10. Use of a PhET Interactive Simulation in General Chemistry Laboratory: Models of the Hydrogen Atom

    Science.gov (United States)

    Clark, Ted M.; Chamberlain, Julia M.

    2014-01-01

    An activity supporting the PhET interactive simulation, Models of the Hydrogen Atom, has been designed and used in the laboratory portion of a general chemistry course. This article describes the framework used to successfully accomplish implementation on a large scale. The activity guides students through a comparison and analysis of the six…

  11. Steam explosion pretreatment of softwood: the effect of the explosive decompression on enzymatic digestibility.

    Science.gov (United States)

    Pielhop, Thomas; Amgarten, Janick; von Rohr, Philipp Rudolf; Studer, Michael H

    2016-01-01

    Steam explosion pretreatment has been examined in many studies for enhancing the enzymatic digestibility of lignocellulosic biomass and is currently the most common pretreatment method in commercial biorefineries. The information available about the effect of the explosive decompression on the biochemical conversion is, however, very limited, and no studies prove that the latter is actually enhanced by the explosion. Hence, it is of great value to discern between the effect of the explosion on the one hand and the steaming on the other hand, to identify their particular influences on enzymatic digestibility. The effect of the explosive decompression in the steam explosion pretreatment of spruce wood chips on their enzymatic cellulose digestibility was studied systematically. The explosion had a high influence on digestibility, improving it by up to 90 % compared to a steam pretreatment without explosion. Two factors were identified to be essentially responsible for the effect of the explosion on enzymatic digestibility: pretreatment severity and pressure difference of the explosion. A higher pretreatment severity can soften up and weaken the lignocellulose structure more, so that the explosion can better break up the biomass and decrease its particle size, which enhances its digestibility. In particular, increasing the pressure difference of the explosion leads to more defibration, a smaller particle size and a better digestibility. Though differences were found in the micro- and nanostructure of exploded and non-exploded biomass, the only influence of the explosion on digestibility was found to be the macroscopic particle size reduction. Steam explosion treatments with a high severity and a high pressure difference of the explosion lead to a comparatively high cellulose digestibility of the-typically very recalcitrant-softwood biomass. This is the first study to show that explosion can enhance the enzymatic digestibility of lignocellulosic biomass. If the

  12. Frequency of damage by external explosion hazards based on geographical information

    International Nuclear Information System (INIS)

    Becker, Guenter; Camarinopoulos, Alexis; Theodora, Karali; Camarinopoulos, Leonidas; Schubert, B.

    2013-01-01

    External explosions can significantly contribute to risk of damage for industrial plants. External explosions may origin from other plants in the neighbourhood, which store and operate with explosive substances, or from transport of such substances on road, rail, or water. If deflagration is involved, ignition will not necessarily occur at the place of the accident, but a cloud of a combustible gas-air mixture may develop, which will ignite at some distance depending on wind velocity. A probabilistic model has been developed to calculate frequencies of damage based on numerical integration or on Monte Carlo simulation. Geographical information systems provide map material for sites, roads, rail and rivers on a computer. Data has been collected and applied for a nuclear power plant in Germany as an example. The method, however, can be used for any type of plant subject to external explosion hazards. (orig.)

  13. Frequency of damage by external explosion hazards based on geographical information

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Guenter [Risa Sicherheitsanalysen GmbH, Berlin-Charlottenburg (Germany); Camarinopoulos, Alexis; Theodora, Karali [Environment Reliability and Risk Analysis (ERRA), Athens (Greece); Camarinopoulos, Leonidas [Piraeus Univ. (Greece); Schubert, B. [VENE, Hamburg (Germany)

    2013-05-15

    External explosions can significantly contribute to risk of damage for industrial plants. External explosions may origin from other plants in the neighbourhood, which store and operate with explosive substances, or from transport of such substances on road, rail, or water. If deflagration is involved, ignition will not necessarily occur at the place of the accident, but a cloud of a combustible gas-air mixture may develop, which will ignite at some distance depending on wind velocity. A probabilistic model has been developed to calculate frequencies of damage based on numerical integration or on Monte Carlo simulation. Geographical information systems provide map material for sites, roads, rail and rivers on a computer. Data has been collected and applied for a nuclear power plant in Germany as an example. The method, however, can be used for any type of plant subject to external explosion hazards. (orig.)

  14. Modeling of tamped and decoupled explosions in salt (simulation is easy. Prediction is difficult exclamation point)

    International Nuclear Information System (INIS)

    Goldstein, P.; Glenn, L.A.

    1993-01-01

    We compare predictions of the strain hardening model of Glenn (1990), with and without damage, to free field and seismic observations of SALMON, STERLING, and 64 kt (tamped) and 8 kt (decoupled) explosions in an Azgir salt dome in the former Soviet Union (FSU). We find good agreement between the model (without damage) and observations of both SALMON and STERLING. In contrast, the average spectral ratio of the tamped to decoupled Azgir explosions is systematically smaller than predicted by the strain hardening model without damage. Much better agreement is obtained when damage is included in the model of the decoupled Azgir explosion

  15. Modeling of tamped and decoupled explosions in salt (Simulation is easy. Prediction is difficult exclamation point)

    International Nuclear Information System (INIS)

    Goldstein, P.; Glenn, L.A.

    1993-05-01

    We compare predictions of the strain hardening model of Glenn (1990), with and without damage, to free field and seismic observations of SALMON, STERLING, and 64 kt (tamped) and 8 kt (decoupled) explosions in an Azgir salt dome in the former Soviet Union (FSU). We find good agreement between the model (without damage) and observations of both SALMON and STERLING. In contrast, the average spectral ratio of the tamped to decoupled Azgir explosions is systematically smaller than predicted by the strain hardening model without damage. Much better agreement is obtained when damage is included in the model of the decoupled Azgir explosion

  16. Polar boundary layer bromine explosion and ozone depletion events in the chemistry-climate model EMAC v2.52: implementation and evaluation of AirSnow algorithm

    Science.gov (United States)

    Falk, Stefanie; Sinnhuber, Björn-Martin

    2018-03-01

    Ozone depletion events (ODEs) in the polar boundary layer have been observed frequently during springtime. They are related to events of boundary layer enhancement of bromine. Consequently, increased amounts of boundary layer volume mixing ratio (VMR) and vertical column densities (VCDs) of BrO have been observed by in situ observation, ground-based as well as airborne remote sensing, and from satellites. These so-called bromine explosion (BE) events have been discussed serving as a source of tropospheric BrO at high latitudes, which has been underestimated in global models so far. We have implemented a treatment of bromine release and recycling on sea-ice- and snow-covered surfaces in the global chemistry-climate model EMAC (ECHAM/MESSy Atmospheric Chemistry) based on the scheme of Toyota et al. (2011). In this scheme, dry deposition fluxes of HBr, HOBr, and BrNO3 over ice- and snow-covered surfaces are recycled into Br2 fluxes. In addition, dry deposition of O3, dependent on temperature and sunlight, triggers a Br2 release from surfaces associated with first-year sea ice. Many aspects of observed bromine enhancements and associated episodes of near-complete depletion of boundary layer ozone, both in the Arctic and in the Antarctic, are reproduced by this relatively simple approach. We present first results from our global model studies extending over a full annual cycle, including comparisons with Global Ozone Monitoring Experiment (GOME) satellite BrO VCDs and surface ozone observations.

  17. Neutron Star Kicks by the Gravitational Tug-boat Mechanism in Asymmetric Supernova Explosions: Progenitor and Explosion Dependence

    Energy Technology Data Exchange (ETDEWEB)

    Janka, Hans-Thomas [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany)

    2017-03-01

    Asymmetric mass ejection in the early phase of supernova (SN) explosions can impart a kick velocity to the new-born neutron star (NS). For neutrino-driven explosions the NS acceleration has been shown to be mainly caused by the gravitational attraction of the anisotropically expelled inner ejecta, while hydrodynamic forces contribute on a subdominant level, and asymmetric neutrino emission plays only a secondary role. Two- and three-dimensional hydrodynamic simulations have demonstrated that this gravitational tug-boat mechanism can explain the observed space velocities of young NSs up to more than 1000 km s{sup −1}. Here, we discuss how the NS kick depends on the energy, ejecta mass, and asymmetry of the SN explosion, and what role the compactness of the pre-collapse stellar core plays for the momentum transfer to the NS. We also provide simple analytic expressions for the NS velocity in terms of these quantities. Referring to results of hydrodynamic simulations in the literature, we argue why, within the discussed scenario of NS acceleration, electron-capture SNe, low-mass Fe-core SNe, and ultra-stripped SNe can be expected to have considerably lower intrinsic NS kicks than core-collapse SNe of massive stellar cores. Our basic arguments also remain valid if progenitor stars possess large-scale asymmetries in their convective silicon and oxygen burning layers. Possible scenarios for spin-kick alignment are sketched. Much of our discussion stays on a conceptual and qualitative level, and more work is necessary on the numerical modeling side to determine the dependences of involved parameters, whose prescriptions will be needed for recipes that can be used to better describe NS kicks in binary evolution and population synthesis studies.

  18. The role of atmospheric nuclear explosions on the stagnation of global warming in the mid 20th century

    Science.gov (United States)

    Fujii, Yoshiaki

    2011-04-01

    This study suggests that the cause of the stagnation in global warming in the mid 20th century was the atmospheric nuclear explosions detonated between 1945 and 1980. The estimated GST drop due to fine dust from the actual atmospheric nuclear explosions based on the published simulation results by other researchers (a single column model and Atmosphere-Ocean General Circulation Model) has served to explain the stagnation in global warming. Atmospheric nuclear explosions can be regarded as full-scale in situ tests for nuclear winter. The non-negligible amount of GST drop from the actual atmospheric explosions suggests that nuclear winter is not just a theory but has actually occurred, albeit on a small scale. The accuracy of the simulations of GST by IPCC would also be improved significantly by introducing the influence of fine dust from the actual atmospheric nuclear explosions into their climate models; thus, global warming behavior could be more accurately predicted.

  19. Automated chemical kinetic modeling via hybrid reactive molecular dynamics and quantum chemistry simulations.

    Science.gov (United States)

    Döntgen, Malte; Schmalz, Felix; Kopp, Wassja A; Kröger, Leif C; Leonhard, Kai

    2018-06-13

    An automated scheme for obtaining chemical kinetic models from scratch using reactive molecular dynamics and quantum chemistry simulations is presented. This methodology combines the phase space sampling of reactive molecular dynamics with the thermochemistry and kinetics prediction capabilities of quantum mechanics. This scheme provides the NASA polynomial and modified Arrhenius equation parameters for all species and reactions that are observed during the simulation and supplies them in the ChemKin format. The ab initio level of theory for predictions is easily exchangeable and the presently used G3MP2 level of theory is found to reliably reproduce hydrogen and methane oxidation thermochemistry and kinetics data. Chemical kinetic models obtained with this approach are ready-to-use for, e.g., ignition delay time simulations, as shown for hydrogen combustion. The presented extension of the ChemTraYzer approach can be used as a basis for methodologically advancing chemical kinetic modeling schemes and as a black-box approach to generate chemical kinetic models.

  20. Response of Radon in a seismic calibration explosion, Israel

    International Nuclear Information System (INIS)

    Zafrir, H.; Steinitz, G.; Malik, U.; Haquin, G.; Gazit-Yaari, N.

    2009-01-01

    Radon measurements were performed at shallow levels during an in-land 20-ton seismic calibration explosion experiment, simulating a 2.6-M L earthquake, to investigate the influence of the explosive blast and the transitory seismic wave fields on the Radon transport in the country rock, adjacent to the focus of the explosion. The experiment was conducted in a basalt quarry in the northern margin of the Beit Shean valley (Israel). Five gamma-ray sensors were placed, at a depth of about 2 m, along a line located 17-150 m from the edge of the explosion zone. Measurements commenced 4 days before and continued for 9 days after the explosion with 15 min integrations. A 10-s sampling was used in the interval of several hours before and after the explosion itself. Diurnal variations of Radon, reflecting the typical variation pattern of Radon in the shallow environment, were registered before and after the explosion. No significant change in the overall Radon concentration was observed as a consequence of the main explosion as well as three smaller experimental shots (0.5-2 tons) in the 2 h prior to the calibration blast. The seismological data indicate that the transient excess pressure at the farthest Radon sensor was above 5 bar m -1 during 0.2-0.4 s, and evidently much higher at the nearest sensors, but none of the sensors responded by recording any exceptional change in the Radon concentration. Moreover the hypothesis that additional Radon may emanate from solid grains as a result of the excess local pressure exerted by the blast is also not observed. In contrast to a real earthquake event an explosion experiment has neither eventual preceding nor following geodynamic activity. Therefore the absence of significant Radon anomalies during or after the blast does not contradict assumptions, observations or conclusions as the occurrence of Radon anomalies prior or after an earthquake event due to associated long-term geodynamic processes.

  1. The Physical Basis of Lg Generation by Explosion Sources

    Energy Technology Data Exchange (ETDEWEB)

    J. L. Stevens; G. E. Baker; H. Xu; T. J. Bennett; N. Rimer; S. D. Day

    2004-12-20

    more so to Lg coda at frequencies less than 1 Hz, but contributes less at higher frequencies than Lg generated directly by the explosion or by surface P-to-S conversion. This report is organized as follows. We first present a review of the extensive body of work on explosion generated shear waves, from which we have tried to extract the most robust observations that constrain the possible mechanisms. That is followed by a presentation of our own observations, from very near source, through local to regional distances for a range of source conditions, and a discussion of the implications of our observations. The observational work is complemented by three distinct types of simulations, one set focused on source physics, one on the effect of scattering due to topography and lateral heterogeneity on Lg, and a new type of modal calculation that simulates Rg to Lg scattering.

  2. Computer simulation of hydrogen diffusion and hydride precipitation at Ta/Zr bond interface. Hydrogen embrittlement in SUS304ULC/Ta/Zr explosive bonded joint

    International Nuclear Information System (INIS)

    Saida, Kazuyoshi; Fujimoto, Tetsuya; Nishimoto, Kazutoshi

    2010-01-01

    The concentration of hydrogen and precipitation of zirconium hydrides in Ta/Zr explosive bonded joint were analysed by computer simulation. Numerical model of hydride precipitation under hydrogen diffusion was simplified by the alternate model coupled the macroscopic hydrogen diffusion with the microscopic hydride precipitation. Effects of the initial hydrogen content in Ta, working degree of Zr and post-bond heat treatment on the hydrogen diffusion and hydride precipitation were investigated. Hydrogen was rapidly diffused from Ta substrate into Zr after explosive bonding and temporarily concentrated at Ta/Zr bond interface. Zirconium hydrides were precipitated and grew at Ta/Zr bond interface, and the precipitation zone of hydrides was enlarged with the lapse of time. The precipitation of zirconium hydrides was promoted when the initial hydrogen content in Ta and working degree of Zr were increased. The concentration of hydrogen and precipitation of hydrides at the bond interface were reduced and diminished by post-bond heat treatment at 373 K. It was deduced that hydrogen embrittlement in Ta/Zr explosive bonded joint was caused by the precipitation of zirconium hydrides and concentration of hydrogen at Ta/Zr bond interface during the diffusion of hydrogen containing in Ta substrate. (author)

  3. A new version of the CNRM Chemistry-Climate Model, CNRM-CCM: description and improvements from the CCMVal-2 simulations

    Directory of Open Access Journals (Sweden)

    M. Michou

    2011-10-01

    Full Text Available This paper presents a new version of the Météo-France CNRM Chemistry-Climate Model, so-called CNRM-CCM. It includes some fundamental changes from the previous version (CNRM-ACM which was extensively evaluated in the context of the CCMVal-2 validation activity. The most notable changes concern the radiative code of the GCM, and the inclusion of the detailed stratospheric chemistry of our Chemistry-Transport model MOCAGE on-line within the GCM. A 47-yr transient simulation (1960–2006 is the basis of our analysis. CNRM-CCM generates satisfactory dynamical and chemical fields in the stratosphere. Several shortcomings of CNRM-ACM simulations for CCMVal-2 that resulted from an erroneous representation of the impact of volcanic aerosols as well as from transport deficiencies have been eliminated.

    Remaining problems concern the upper stratosphere (5 to 1 hPa where temperatures are too high, and where there are biases in the NO2, N2O5 and O3 mixing ratios. In contrast, temperatures at the tropical tropopause are too cold. These issues are addressed through the implementation of a more accurate radiation scheme at short wavelengths. Despite these problems we show that this new CNRM CCM is a useful tool to study chemistry-climate applications.

  4. Studies of the laser-induced fluorescence of explosives and explosive compositions.

    Energy Technology Data Exchange (ETDEWEB)

    Hargis, Philip Joseph, Jr. (,; .); Thorne, Lawrence R.; Phifer, Carol Celeste; Parmeter, John Ethan; Schmitt, Randal L.

    2006-10-01

    Continuing use of explosives by terrorists throughout the world has led to great interest in explosives detection technology, especially in technologies that have potential for standoff detection. This LDRD was undertaken in order to investigate the possible detection of explosive particulates at safe standoff distances in an attempt to identify vehicles that might contain large vehicle bombs (LVBs). The explosives investigated have included the common homogeneous or molecular explosives, 2,4,6-trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), cyclonite or hexogen (RDX), octogen (HMX), and the heterogeneous explosive, ammonium nitrate/fuel oil (ANFO), and its components. We have investigated standard excited/dispersed fluorescence, laser-excited prompt and delayed dispersed fluorescence using excitation wavelengths of 266 and 355 nm, the effects of polarization of the laser excitation light, and fluorescence imaging microscopy using 365- and 470-nm excitation. The four nitro-based, homogeneous explosives (TNT, PETN, RDX, and HMX) exhibit virtually no native fluorescence, but do exhibit quenching effects of varying magnitude when adsorbed on fluorescing surfaces. Ammonium nitrate and fuel oil mixtures fluoresce primarily due to the fuel oil, and, in some cases, due to the presence of hydrophobic coatings on ammonium nitrate prill or impurities in the ammonium nitrate itself. Pure ammonium nitrate shows no detectable fluorescence. These results are of scientific interest, but they provide little hope for the use of UV-excited fluorescence as a technique to perform safe standoff detection of adsorbed explosive particulates under real-world conditions with a useful degree of reliability.

  5. Parameters of explosives detection through tagged neutron method

    Energy Technology Data Exchange (ETDEWEB)

    Bagdasaryan, Kh.E.; Batyaev, V.F.; Belichenko, S.G., E-mail: consul757@mail.ru; Bestaev, R.R.; Gavryuchenkov, A.V.; Karetnikov, M.D.

    2015-06-01

    The potentialities of tagged neutron method (TNM) for explosives detection are examined on the basis of an idealized geometrical model. The model includes ING-27 14 MeV neutron generator with a built-in α-detector, a LYSO γ-detector and samples of material to be identified of approximately 0.3 kg each: explosives imitators (trinitrotoluene - TNT, tetryl, RDX and ammonium nitrate), legal materials (sugar, water, silk and polyethylene). The samples were unshielded or shielded by a paper layer of various thicknesses. The experimental data were interpreted by numerical simulation using a Poisson distribution of signals with the statistical parameters defined experimentally. The detection parameters were obtained by a pattern classification theory and a Bayes classifier.

  6. 76 FR 64974 - Commerce in Explosives; List of Explosive Materials (2011R-18T)

    Science.gov (United States)

    2011-10-19

    ... slurry and water gel explosives. Blasting caps. Blasting gelatin. Blasting powder. BTNEC [bis.... Esters of nitro-substituted alcohols. Ethyl-tetryl. Explosive conitrates. Explosive gelatins. Explosive... silver. Fulminating gold. Fulminating mercury. Fulminating platinum. Fulminating silver. G Gelatinized...

  7. Comparative parametric numerical simulations of materials used as liners in the explosively formed projectiles (EFPs)

    International Nuclear Information System (INIS)

    Hussain, G.; Sanaullah, K.

    2009-01-01

    A conventional shaped charge comprises a conical metal liner projecting a hyper velocity jet of metal that is able to penetrate to great depths into steel armour. However, misalignment problems exist in tandem with jet break up and spewing particles that greatly diminish its penetration power. An EFP, on the other hand, has a liner in the shape of a geometrical recess. The force of the blast molds the liner into a number of configurations, depending on the geometry and the explosive detonation characteristics. This paper presents comparative parametric numerical simulations of materials used as liners in the explosively formed projectiles EFPs. Numerical simulations are carried out using AUTODYN 2D hydrocode to study effects of liner's materials on the shape, velocity, traveled distance, time, pressure, internal energy, temperature, yield stress, divergence or stability, density, compression, and length to diameter (L/D) ratio of EFPs. These parameters are estimated at the instants of maximum as well as at stable velocities. The parametric study reveals that aluminum has maximum velocity in shortest time among the liner materials. From this reason, it was concluded effective standoff was greater for aluminum than more denser metals. Maximum velocity and traveled distance of Tantalum EFP is found to be minimum which may be due to low thermal softening exponent and larger hardening exponent. The simulated yield stress and pressure developed in the Fe EFP reaches at maximum. The L/D ratio for Copper is found to be maximum which supports maximum penetration. From the stability point of view, 1006 MS is found to be the most reliable liner material due to minimum divergence. Generally all liner materials have similar effects of all parameters like pressure, internal energy, temperature, yield stress, divergence or stability, density, compression at the instants of maximum as well as at stable velocities except L/D ratio of EFPs. At the instant of maximum velocity, L

  8. Large-scale tropospheric transport in the Chemistry-Climate Model Initiative (CCMI) simulations

    Science.gov (United States)

    Orbe, Clara; Yang, Huang; Waugh, Darryn W.; Zeng, Guang; Morgenstern, Olaf; Kinnison, Douglas E.; Lamarque, Jean-Francois; Tilmes, Simone; Plummer, David A.; Scinocca, John F.; Josse, Beatrice; Marecal, Virginie; Jöckel, Patrick; Oman, Luke D.; Strahan, Susan E.; Deushi, Makoto; Tanaka, Taichu Y.; Yoshida, Kohei; Akiyoshi, Hideharu; Yamashita, Yousuke; Stenke, Andreas; Revell, Laura; Sukhodolov, Timofei; Rozanov, Eugene; Pitari, Giovanni; Visioni, Daniele; Stone, Kane A.; Schofield, Robyn; Banerjee, Antara

    2018-05-01

    Understanding and modeling the large-scale transport of trace gases and aerosols is important for interpreting past (and projecting future) changes in atmospheric composition. Here we show that there are large differences in the global-scale atmospheric transport properties among the models participating in the IGAC SPARC Chemistry-Climate Model Initiative (CCMI). Specifically, we find up to 40 % differences in the transport timescales connecting the Northern Hemisphere (NH) midlatitude surface to the Arctic and to Southern Hemisphere high latitudes, where the mean age ranges between 1.7 and 2.6 years. We show that these differences are related to large differences in vertical transport among the simulations, in particular to differences in parameterized convection over the oceans. While stronger convection over NH midlatitudes is associated with slower transport to the Arctic, stronger convection in the tropics and subtropics is associated with faster interhemispheric transport. We also show that the differences among simulations constrained with fields derived from the same reanalysis products are as large as (and in some cases larger than) the differences among free-running simulations, most likely due to larger differences in parameterized convection. Our results indicate that care must be taken when using simulations constrained with analyzed winds to interpret the influence of meteorology on tropospheric composition.

  9. 77 FR 58410 - Commerce in Explosives; List of Explosive Materials (2012R-10T)

    Science.gov (United States)

    2012-09-20

    ... sensitive slurry and water gel explosives. Blasting caps. Blasting gelatin. Blasting powder. BTNEC [bis.... Esters of nitro-substituted alcohols. Ethyl-tetryl. Explosive conitrates. Explosive gelatins. Explosive.... Fulminate of silver. Fulminating gold. Fulminating mercury. Fulminating platinum. Fulminating silver. G...

  10. Strong explosions impact on buildings representative of an industrial facility; Impact de fortes explosions sur les batiments representatifs d'une installation industrielle

    Energy Technology Data Exchange (ETDEWEB)

    Trelat, S

    2006-12-15

    The goal of this study is to focus on the analysis of blast wave damage to structures when blast wave is consequence of explosive charge detonation. The objective is to propose useful tools to predict charges on structure. All experiences are realized in laboratory. The experimental investigation consists in simulating a detonation of a stoichiometric propane-oxygen mixture at ground level or at higher altitude. The study is going to give us experimental data on blast wave effects on a structure. For that, two types of structures frequently found on industrial site are going to be used: a parallelepipedal structure and a cylindrical structure, both with known dimensions. Finally, the important point of the problem is to determine an energetic equivalence between TNT and gas used in the experiments, in order to model TNT explosions at full scale by gaseous explosions at reduced scale. (author)

  11. JASMINE-pro: A computer code for the analysis of propagation process in steam explosions. User's manual

    International Nuclear Information System (INIS)

    Yang, Yanhua; Nilsuwankosit, Sunchai; Moriyama, Kiyofumi; Maruyama, Yu; Nakamura, Hideo; Hashimoto, Kazuichiro

    2000-12-01

    A steam explosion is a phenomenon where a high temperature liquid gives its internal energy very rapidly to another low temperature volatile liquid, causing very strong pressure build up due to rapid vaporization of the latter. In the field of light water reactor safety research, steam explosions caused by the contact of molten core and coolant has been recognized as a potential threat which could cause failure of the pressure vessel or the containment vessel during a severe accident. A numerical simulation code JASMINE was developed at Japan Atomic Energy Research Institute (JAERI) to evaluate the impact of steam explosions on the integrity of reactor boundaries. JASMINE code consists of two parts, JASMINE-pre and -pro, which handle the premixing and propagation phases in steam explosions, respectively. JASMINE-pro code simulates the thermo-hydrodynamics in the propagation phase of a steam explosion on the basis of the multi-fluid model for multiphase flow. This report, 'User's Manual', gives the usage of JASMINE-pro code as well as the information on the code structures which should be useful for users to understand how the code works. (author)

  12. Nuclear explosives testing readiness evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Valk, T.C.

    1993-09-01

    This readiness evaluation considers hole selection and characterization, verification, containment issues, nuclear explosive safety studies, test authorities, event operations planning, canister-rack preparation, site preparation, diagnostic equipment setup, device assembly facilities and processes, device delivery and insertion, emplacement, stemming, control room activities, readiness briefing, arming and firing, test execution, emergency response and reentry, and post event analysis to include device diagnostics, nuclear chemistry, and containment. This survey concludes that the LLNL program and its supporting contractors could execute an event within six months of notification, and a second event within the following six months, given the NET group`s evaluation and the following three restraints: (1) FY94 (and subsequent year) funding is essentially constant with FY93, (2) Preliminary work for the initial event is completed to the historical sic months status, (3) Critical personnel, currently working in dual use technologies, would be recallable as needed.

  13. ICPP custom dissolver explosion recovery

    International Nuclear Information System (INIS)

    Demmer, R.; Hawk, R.

    1992-01-01

    This paper discusses the recovery from the February 9, 1991, small scale explosion in a custom processing dissolver at the Idaho Chemical Processing Plant (ICPP) a Department of Energy facility at the Idaho National Engineering Laboratory. The custom processing facility is a limited production area designed to recover unirradiated uranium fuel. A small amount of the nuclear material received and stored at the ICPP is unique and incompatible with the major head end dissolution processes. Custom processing is a small scale dissolution facility for processing these materials in an economical fashion in the CPP-627 hot chemistry laboratory. Two glass dissolvers were contained in a large walk in hood area. Utilities for dissolution and connections to the major ICPP uranium separation facility were provided. The fuel processing operations during this campaign involved dissolving uranium metal, uranium oxides, and uranium/fissium alloy in nitric acid

  14. Final results of the FY'78 chemistry and materials science research program review

    International Nuclear Information System (INIS)

    Frazer, J.W.

    1977-01-01

    18 projects which were selected to be sponsored by ''Chemistry Research Program'' are summarized. These include: lasers for chemical analysis; multi-element analysis systems; spectroscopic analysis of surface passivation; non-aqueous titrimetry; materials damage prediction for fiber composites; safe high energy explosives; single photon absorption reaction chemistry; reaction in shock waves; cryogenic heavy hydrogen technology; acoustic emission; metallic alloy glasses; basic study of toughness in steel; static equation-of-state at 100 GPa; transuranium element research; nuclear structure research; neutron capture gamma measurements; x-ray fluorescence analysis; and pyrochemical investigation

  15. TRACER-II: a complete computational model for mixing and propagation of vapor explosions

    Energy Technology Data Exchange (ETDEWEB)

    Bang, K.H. [School of Mechanical Engineering, Korea Maritime Univ., Pusan (Korea, Republic of); Park, I.G.; Park, G.C.

    1998-01-01

    A vapor explosion is a physical process in which very rapid energy transfer occurs between a hot liquid and a volatile, colder liquid when the two liquids come into a sudden contact. For the analyses of potential impacts from such explosive events, a computer program, TRACER-II, has been developed, which contains a complete description of mixing and propagation phases of vapor explosions. The model consists of fuel, fragmented fuel (debris), coolant liquid, and coolant vapor in two-dimensional Eulerian coordinates. The set of governing equations are solved numerically using finite difference method. The results of this numerical simulation of vapor explosions are discussed in comparison with the recent experimental data of FARO and KROTOS tests. When compared to some selected FARO and KROTOS data, the fuel-coolant mixing and explosion propagation behavior agree reasonably with the data, although the results are yet sensitive primarily to the melt breakup and fragmentation modeling. (author)

  16. Improved sensitivity testing of explosives using transformed Up-Down methods

    International Nuclear Information System (INIS)

    Brown, Geoffrey W

    2014-01-01

    Sensitivity tests provide data that help establish guidelines for the safe handling of explosives. Any sensitivity test is based on assumptions to simplify the method or reduce the number of individual sample evaluations. Two common assumptions that are not typically checked after testing are 1) explosive response follows a normal distribution as a function of the applied stimulus levels and 2) the chosen test level spacing is close to the standard deviation of the explosive response function (for Bruceton Up-Down testing for example). These assumptions and other limitations of traditional explosive sensitivity testing can be addressed using Transformed Up-Down (TUD) test methods. TUD methods have been developed extensively for psychometric testing over the past 50 years and generally use multiple tests at a given level to determine how to adjust the applied stimulus. In the context of explosive sensitivity we can use TUD methods that concentrate testing around useful probability levels. Here, these methods are explained and compared to Bruceton Up-Down testing using computer simulation. The results show that the TUD methods are more useful for many cases but that they do require more tests as a consequence. For non-normal distributions, however, the TUD methods may be the only accurate assessment method.

  17. Investigation of the explosion hazards of hydrogen sulphide. Phase II

    International Nuclear Information System (INIS)

    Moen, I.O.

    1986-01-01

    The results of Phase II of an investigation directed towards quantifying the explosive hazards of hydrogen sulphide in air are described. This second and final phase is focussed on flame acceleration until detonation in obstacle environments simulating a heavy water plant. The results of previous experimental tests, both small and large scale, are compiled and summarized and the results of a series of flame acceleration tests are reported. These tests were performed in order to assess the potential for damaging explosions in simulated industrial environments with repeated obstacles. The experimented apparatus consisted of a channel 1.8 m x 1.8 m in cross-section and 15.5 m long. Two obstacle configurations were tested, corresponding to 500 mm or 220 mm diameter tubes mounted across the channel at regular intervals. Tests were performed with acetylene, propane and hydrogen sulphide fuels. The results of numerical simulation are also reported and compared with the observed results. Scaling predictions are also made. The key results are summarized in the main text, and detailed reports covering the various aspects are included in three annexes

  18. Investigation of the explosion hazards of hydrogen sulphide. (Phase II)

    International Nuclear Information System (INIS)

    Moen, I.O.

    1986-01-01

    The results of Phase II of an investigation directed towards quantifying the explosive hazards of hydrogen sulphide in air are described. This second and final phase is focussed on flame acceleration until detonation in obstacle environments simulating a heavy water plant. The results of previous experimental tests, both small and large scale, are compiled and summarized and the results of a series of flame acceleration tests are reported. These tests were performed in order to assess the potential for damaging explosions in simulated industrial environments with repeated obstacles. The experimented apparatus consisted of a channel 1.8 m x 1.8 m in cross-section and 15.5 m long. Two obstacle configurations were tested, corresponding to 500 mm or 220 mm diameter tubes mounted across the channel at regular intervals. Tests were performed with acetylene, propane and hydrogen sulphide fuels. The results of numerical simulation are also reported and compared with the observed results. Scaling predictions are also made. The key results are summarized in the main text, and detailed reports covering the various aspects are included in three annexes

  19. Underground nuclear explosions

    International Nuclear Information System (INIS)

    Higgins, Gary H.

    1970-01-01

    In the Third Plowshare Symposium, held in 1964, data from a number of nuclear explosions were presented. At that time the basic elements of the nuclear explosion appeared to be well understood and relationships for predicting the gross nuclear effects were presented. Since that time, additional work has been done and many of the concepts have been extended. For example, nuclear explosions have been conducted at greater depths and with much greater yields. The physical and chemical properties of the material in which the explosions occur have been more accurately measured and related to explosion effects. Interpretation of the new information seems to indicate that the earlier relationships are valid over the ranges of energy and depths for which data is available but that effects relating to cavity and chimney sizes or fracturing had been overestimated at great depths of burst and higher yields. (author)

  20. Underground nuclear explosions

    Energy Technology Data Exchange (ETDEWEB)

    Higgins, Gary H [Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)

    1970-05-01

    In the Third Plowshare Symposium, held in 1964, data from a number of nuclear explosions were presented. At that time the basic elements of the nuclear explosion appeared to be well understood and relationships for predicting the gross nuclear effects were presented. Since that time, additional work has been done and many of the concepts have been extended. For example, nuclear explosions have been conducted at greater depths and with much greater yields. The physical and chemical properties of the material in which the explosions occur have been more accurately measured and related to explosion effects. Interpretation of the new information seems to indicate that the earlier relationships are valid over the ranges of energy and depths for which data is available but that effects relating to cavity and chimney sizes or fracturing had been overestimated at great depths of burst and higher yields. (author)

  1. ALPHA visual data collection. STX005-025: melt drop steam explosion experiments

    International Nuclear Information System (INIS)

    Moriyama, Kiyofumi; Yamano, Norihiro; Maruyama, Yu; Kudo, Tamotsu; Sugimoto, Jun

    1999-03-01

    Steam explosion is a phenomenon in which a high temperature liquid gives its internal energy to a low temperature volatile liquid extremely quickly causing rapid evaporation and shock wave generation. In the field of nuclear reactor safety research regarding severe accidents in LWRs, steam explosions involving molten fuel and coolant has been recognized as a potential threat to the integrity of the reactor containment vessel. In the ALPHA (Assessment of Loads and Performance of Containment in Hypothetical Accident) program, experiments were performed to investigate the phenomenology of vapor explosions using iron-alumina thermite melt as a simulant of molten core. This report collects the experimental results especially emphasizing the visual observations by high speed photography. (author)

  2. Evaluation of the pressure loads generated by hydrogen explosion in auxiliary nuclear building

    International Nuclear Information System (INIS)

    Ahmed Bentaib; Alexandre Bleyer; Pierre Pailhories; Jean-Pierre L'heriteau; Bernard Chaumont; Jerome Dupas; Jerome Riviere

    2005-01-01

    Full text of publication follows: In the framework of nuclear safety, a hydrogen leaks in the auxiliary nuclear building would raise a explosion hazard. A local ignition of the combustible mixture would give birth initially to a slow flame, rapidly accelerated by obstacles. This flame acceleration is responsible for high pressure loads that can damage the auxiliary building and destroy safety equipments in it. In this paper, we evaluate the pressure loads generated by an hydrogen explosion for both bounding and realistic explosion scenarios. The bounding scenarios use stoichiometric hydrogen-air mixtures and the realistic scenarios correspond to hydrogen leaks with mass flow rate varying between 1 g/s and 9 g/s. For every scenario, the impact of the ignition location and ignition time are investigated. The hydrogen dispersion and explosion are computed using the TONUS code. The dispersion model used is based on a finite element solver and the explosion is simulated by a structured finite volumes EULER equation solver and the combustion model CREBCOM which simulates the hydrogen/air turbulent flame propagation, taking into account 3D complex geometry and reactants concentration gradients. The pressure loads computed are then used to investigate the occurrence of a mechanical failure of the tanks located in the auxiliary nuclear building and containing radioactive fluids. The EUROPLEXUS code is used to perform 3D mechanical calculations because the loads are non uniform and of rather short deviation. (authors)

  3. An integral condition for core-collapse supernova explosions

    International Nuclear Information System (INIS)

    Murphy, Jeremiah W.; Dolence, Joshua C.

    2017-01-01

    Here, we derive an integral condition for core-collapse supernova (CCSN) explosions and use it to construct a new diagnostic of explodability. The fundamental challenge in CCSN theory is to explain how a stalled accretion shock revives to explode a star. In this manuscript, we assume that the shock revival is initiated by the delayed-neutrino mechanism and derive an integral condition for spherically symmetric shock expansion, v_s > 0. One of the most useful one-dimensional explosion conditions is the neutrino luminosity and mass-accretion rate (L_ν-- M-dot ) critical curve. Below this curve, steady-state stalled solutions exist, but above this curve, there are no stalled solutions. Burrows & Goshy suggested that the solutions above this curve are dynamic and explosive. In this manuscript, we take one step closer to proving this supposition; we show that all steady solutions above this curve have v_s > 0. Assuming that these steady v_s > 0 solutions correspond to explosion, we present a new dimensionless integral condition for explosion, Ψ > 0. Ψ roughly describes the balance between pressure and gravity, and we show that this parameter is equivalent to the τ condition used to infer the L_ν-- M-dot critical curve. The illuminating difference is that there is a direct relationship between Ψ and v_s. Below the critical curve, Ψ may be negative, positive, and zero, which corresponds to receding, expanding, and stalled-shock solutions. At the critical curve, the minimum Ψ solution is zero; above the critical curve, Ψ_m_i_n > 0, and all steady solutions have v_s > 0. Using one-dimensional simulations, we confirm our primary assumptions and verify that Ψ_m_i_n > 0 is a reliable and accurate explosion diagnostic.

  4. Data assimilation in atmospheric chemistry models: current status and future prospects for coupled chemistry meteorology models

    OpenAIRE

    M. Bocquet; H. Elbern; H. Eskes; M. Hirtl; R. Žabkar; G. R. Carmichael; J. Flemming; A. Inness; M. Pagowski; J. L. Pérez Camaño; P. E. Saide; R. San Jose; M. Sofiev; J. Vira; A. Baklanov

    2015-01-01

    Data assimilation is used in atmospheric chemistry models to improve air quality forecasts, construct re-analyses of three-dimensional chemical (including aerosol) concentrations and perform inverse modeling of input variables or model parameters (e.g., emissions). Coupled chemistry meteorology models (CCMM) are atmospheric chemistry models that simulate meteorological processes and chemical transformations jointly. They offer the possibility to assimilate both meteorologica...

  5. Low temperature surface chemistry and nanostructures

    Science.gov (United States)

    Sergeev, G. B.; Shabatina, T. I.

    2002-03-01

    The new scientific field of low temperature surface chemistry, which combines the low temperature chemistry (cryochemistry) and surface chemistry approaches, is reviewed in this paper. One of the most exciting achievements in this field of science is the development of methods to create highly ordered hybrid nanosized structures on different organic and inorganic surfaces and to encapsulate nanosized metal particles in organic and polymer matrices. We consider physical and chemical behaviour for the systems obtained by co-condensation of the components vapours on the surfaces cooled down to 4-10 and 70-100 K. In particular the size effect of both types, the number of atoms in the reactive species structure and the thickness of growing co-condensate film, on the chemical activity of the system is analysed in detail. The effect of the internal mechanical stresses on the growing interfacial co-condensate film formation and on the generation of fast (explosive) spontaneous reactions at low temperatures is discussed. The examples of unusual chemical interactions of metal atoms, clusters and nanosized particles, obtained in co-condensate films on the cooled surfaces under different conditions, are presented. The examples of highly ordered surface and volume hybrid nanostructures formation are analysed.

  6. Polar Processes in a 50-year Simulation of Stratospheric Chemistry and Transport

    Science.gov (United States)

    Kawa, S.R.; Douglass, A. R.; Patrick, L. C.; Allen, D. R.; Randall, C. E.

    2004-01-01

    The unique chemical, dynamical, and microphysical processes that occur in the winter polar lower stratosphere are expected to interact strongly with changing climate and trace gas abundances. Significant changes in ozone have been observed and prediction of future ozone and climate interactions depends on modeling these processes successfully. We have conducted an off-line model simulation of the stratosphere for trace gas conditions representative of 1975-2025 using meteorology from the NASA finite-volume general circulation model. The objective of this simulation is to examine the sensitivity of stratospheric ozone and chemical change to varying meteorology and trace gas inputs. This presentation will examine the dependence of ozone and related processes in polar regions on the climatological and trace gas changes in the model. The model past performance is base-lined against available observations, and a future ozone recovery scenario is forecast. Overall the model ozone simulation is quite realistic, but initial analysis of the detailed evolution of some observable processes suggests systematic shortcomings in our description of the polar chemical rates and/or mechanisms. Model sensitivities, strengths, and weaknesses will be discussed with implications for uncertainty and confidence in coupled climate chemistry predictions.

  7. Testing the equation of state and electrical conductivity of copper by the electrical wire explosion in air: Experiment and magnetohydrodynamic simulation

    International Nuclear Information System (INIS)

    Barysevich, A. E.; Cherkas, S. L.

    2011-01-01

    We perform experiments on testing the equations of state and electrical conductivity of copper in three different regimes of copper wire electrical explosion, when the inserted energy (i) is slightly exceeded, (ii) is approximately equal, and (iii) is substantially exceeded the energy needed for the wire complete evaporation. Magnetohydrodynamic simulation is performed. The results predicted by the two different equations of state are compared with the experiment. Empirical expression for the copper electrical conductivity is presented. Parameters in this expression is fit on every of two equations of state. Map of copper conductivity is plotted.

  8. Towards gravitational-wave astronomy of core-collapse supernova explosion

    International Nuclear Information System (INIS)

    Kotake, Kei

    2010-01-01

    We study properties of gravitational waves based on the three-dimensional (3D) simulations, which demonstrate the neutrino-driven explosions aided by the standing accretion shock instability (SASI). Pushed by evidence supporting slow rotation prior to core-collapse, we focus on the asphericities in neutrino emissions and matter motions outside the protoneutron star. By performing a ray-tracing calculation in 3D, we estimate accurately the gravitational waveforms from anisotropic neutrino emissions. In contrast to the previous work assuming axisymmetry, we find that the gravitational waveforms vary much more stochastically because the explosion anisotropies depend sensitively on the growth of the SASI which develops chaotically in all directions. Our results show that the gravitational-wave spectrum has its peak near ∼ 100 Hz, reflecting the SASI-induced matter overturns of ∼ O(10) ms. We point out that the detection of such signals, possibly visible to the LIGO-class detectors for a Galactic supernova, could be an important probe into the long-veiled explosion mechanism.

  9. Verification of fire and explosion accident analysis codes (facility design and preliminary results)

    International Nuclear Information System (INIS)

    Gregory, W.S.; Nichols, B.D.; Talbott, D.V.; Smith, P.R.; Fenton, D.L.

    1985-01-01

    For several years, the US Nuclear Regulatory Commission has sponsored the development of methods for improving capabilities to analyze the effects of postulated accidents in nuclear facilities; the accidents of interest are those that could occur during nuclear materials handling. At the Los Alamos National Laboratory, this program has resulted in three computer codes: FIRAC, EXPAC, and TORAC. These codes are designed to predict the effects of fires, explosions, and tornadoes in nuclear facilities. Particular emphasis is placed on the movement of airborne radioactive material through the gaseous effluent treatment system of a nuclear installation. The design, construction, and calibration of an experimental ventilation system to verify the fire and explosion accident analysis codes are described. The facility features a large industrial heater and several aerosol smoke generators that are used to simulate fires. Both injected thermal energy and aerosol mass can be controlled using this equipment. Explosions are simulated with H 2 /O 2 balloons and small explosive charges. Experimental measurements of temperature, energy, aerosol release rates, smoke concentration, and mass accumulation on HEPA filters can be made. Volumetric flow rate and differential pressures also are monitored. The initial experiments involve varying parameters such as thermal and aerosol rate and ventilation flow rate. FIRAC prediction results are presented. 10 figs

  10. Stellar explosion

    International Nuclear Information System (INIS)

    Suraud, E.

    1987-01-01

    What is the energy source and which physical processes are powerful enough to generate this explosion which scatters the star. The knowledge progress of very dense matter allows the scenario reconstitution. An instability in the star core which is developing during milliseconds is the cause of this explosion [fr

  11. Steam explosion studies review

    International Nuclear Information System (INIS)

    Hwang, Moon Kyu; Kim, Hee Dong

    1999-03-01

    When a cold liquid is brought into contact with a molten material with a temperature significantly higher than the liquid boiling point, an explosive interaction due to sudden fragmentation of the melt and rapid evaporation of the liquid may take place. This phenomenon is referred to as a steam explosion or vapor explosion. Depending upon the amount of the melt and the liquid involved, the mechanical energy released during a vapor explosion can be large enough to cause serious destruction. In hypothetical severe accidents which involve fuel melt down, subsequent interactions between the molten fuel and coolant may cause steam explosion. This process has been studied by many investigators in an effort to assess the likelihood of containment failure which leads to large scale release of radioactive materials to the environment. In an effort to understand the phenomenology of steam explosion, extensive studies has been performed so far. The report presents both experimental and analytical studies on steam explosion. As for the experimental studies, both small scale tests which involve usually less than 20 g of high temperature melt and medium/large scale tests which more than 1 kg of melt is used are reviewed. For the modelling part of steam explosions, mechanistic modelling as well as thermodynamic modelling is reviewed. (author)

  12. Extended Lagrangian Born-Oppenheimer molecular dynamics simulations of the shock-induced chemistry of phenylacetylene

    Energy Technology Data Exchange (ETDEWEB)

    Cawkwell, M. J., E-mail: cawkwell@lanl.gov; Niklasson, Anders M. N. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Dattelbaum, Dana M. [Weapons Experiments Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2015-02-14

    The initial chemical events that occur during the shock compression of liquid phenylacetylene have been investigated using self-consistent tight binding molecular dynamics simulations. The extended Lagrangian Born-Oppenheimer molecular dynamics formalism enabled us to compute microcanonical trajectories with precise conservation of the total energy. Our simulations revealed that the first density-increasing step under shock compression arises from the polymerization of phenylacetylene molecules at the acetylene moiety. The application of electronic structure-based molecular dynamics with long-term conservation of the total energy enabled us to identify electronic signatures of reactivity via monitoring changes in the HOMO-LUMO gap, and to capture directly adiabatic shock heating, transient non-equilibrium states, and changes in temperature arising from exothermic chemistry in classical molecular dynamics trajectories.

  13. Extended Lagrangian Born-Oppenheimer molecular dynamics simulations of the shock-induced chemistry of phenylacetylene.

    Science.gov (United States)

    Cawkwell, M J; Niklasson, Anders M N; Dattelbaum, Dana M

    2015-02-14

    The initial chemical events that occur during the shock compression of liquid phenylacetylene have been investigated using self-consistent tight binding molecular dynamics simulations. The extended Lagrangian Born-Oppenheimer molecular dynamics formalism enabled us to compute microcanonical trajectories with precise conservation of the total energy. Our simulations revealed that the first density-increasing step under shock compression arises from the polymerization of phenylacetylene molecules at the acetylene moiety. The application of electronic structure-based molecular dynamics with long-term conservation of the total energy enabled us to identify electronic signatures of reactivity via monitoring changes in the HOMO-LUMO gap, and to capture directly adiabatic shock heating, transient non-equilibrium states, and changes in temperature arising from exothermic chemistry in classical molecular dynamics trajectories.

  14. Fire and explosion hazards to flora and fauna from explosives.

    Science.gov (United States)

    Merrifield, R

    2000-06-30

    Deliberate or accidental initiation of explosives can produce a range of potentially damaging fire and explosion effects. Quantification of the consequences of such effects upon the surroundings, particularly on people and structures, has always been of paramount importance. Information on the effects on flora and fauna, however, is limited, with probably the weakest area lying with fragmentation of buildings and their effects on different small mammals. Information has been used here to gain an appreciation of the likely magnitude of the potential fire and explosion effects on flora and fauna. This is based on a number of broad assumptions and a variety of data sources including World War II bomb damage, experiments performed with animals 30-40 years ago, and more recent field trials on building break-up under explosive loading.

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

    Science.gov (United States)

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

    2016-06-01

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

  16. Parametric tests of the effects of water chemistry impurities on corrosion of Zr-alloys under simulated BWR condition

    Energy Technology Data Exchange (ETDEWEB)

    Shimada, S; Ito, K [Nippon Nuclear Fuel Development Co. Ltd., Oarai, Ibaraki (Japan); Lin, C C [GE Nucklear Energy (United States); Cheng, B [Electric Power Research Inst. (United States); Ikeda, T [Toshiba Corp. (Japan); Oguma, M [Hitachi, Ltd (Japan); Takei, T [Tokyo Electric Power Co., Inc. (Japan); Vitanza, C; Karlsen, T M [Institutt for Energiteknikk, Halden (Norway). OECD Halden Reaktor Projekt

    1997-02-01

    The Halden BWR corrosion test loop was constructed to evaluate the impact of water chemistry variables, heat flux and boiling condition on corrosion performance of Zr-alloys in a simulated BWR environment. The loop consists of two in-core rigs, one for testing fuel rod segments and the other for evaluating water chemistry variables utilizing four miniautoclaves. Ten coupon specimens are enclosed in each miniautoclave. The Zr-alloys for the test include Zircaloy-2 having different nodular corrosion resistance and five new alloys. The first and second of the six irradiation tests planned in this program were completed. Post-irradiation examination of those test specimens have shown that the test loop is capable of producing nodular corrosion on the fuel rod cladding tested under the reference chemistry condition. The miniautoclave tests showed that nodular corrosion could be formed without flux and boiling under some water chemistry conditions and the new alloys, generally, had higher corrosion resistance than the Zircaloy in high oxygen environments. (author). 5 refs, 4 figs, 5 tabs.

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

    Science.gov (United States)

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

    2016-11-05

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

  18. MEMS-based Porous Silicon Preconcentrators Filled with Carbopack-B for Explosives Detection

    OpenAIRE

    Camara , El Hadji Malik; James , Franck; Breuil , Philippe; Pijolat , Christophe; Briand , Danick; De Rooij , Nicolaas F

    2014-01-01

    International audience; In this paper we report the detection of explosive compounds using a miniaturized gas preconcentrator (μGP) made of porous silicon (PS) filled in with Carbopack B as an adsorbent material. The μGP includes also a platinum heater patterned at the backside and fluidic connectors sealed on the glass cover. Our μGP is designed and optimized through fluidic and thermal simulations for meeting the requirements of trace explosives detection. The thermal mass of the device was...

  19. Predictive Capability of the Compressible MRG Equation for an Explosively Driven Particle with Validation

    Science.gov (United States)

    Garno, Joshua; Ouellet, Frederick; Koneru, Rahul; Balachandar, Sivaramakrishnan; Rollin, Bertrand

    2017-11-01

    An analytic model to describe the hydrodynamic forces on an explosively driven particle is not currently available. The Maxey-Riley-Gatignol (MRG) particle force equation generalized for compressible flows is well-studied in shock-tube applications, and captures the evolution of particle force extracted from controlled shock-tube experiments. In these experiments only the shock-particle interaction was examined, and the effects of the contact line were not investigated. In the present work, the predictive capability of this model is considered for the case where a particle is explosively ejected from a rigid barrel into ambient air. Particle trajectory information extracted from simulations is compared with experimental data. This configuration ensures that both the shock and contact produced by the detonation will influence the motion of the particle. The simulations are carried out using a finite volume, Euler-Lagrange code using the JWL equation of state to handle the explosive products. This work was supported by the U.S. Department of Energy, National Nuclear Security Administration, Advanced Simulation and Computing Program, as a Cooperative Agreement under the Predictive Science Academic Alliance Program,under Contract No. DE-NA0002378.

  20. Comparison of the inelastic response of steel building frames to strong earthquake and underground nuclear explosion ground motion

    International Nuclear Information System (INIS)

    Murray, R.C.; Tokarz, F.J.

    1976-01-01

    Analytic studies were made of the adequacy of simulating earthquake effects at the Nevada Test Site for structural testing purposes. It is concluded that underground nuclear explosion ground motion will produce inelastic behavior and damage comparable to that produced by strong earthquakes. The generally longer duration of earthquakes compared with underground nuclear explosions does not appear to significantly affect the structural behavior of the building frames considered. A comparison of maximum ductility ratios, maximum story drifts, and maximum displacement indicate similar structural behavior for both types of ground motion. Low yield (10 - kt) underground nuclear explosions are capable of producing inelastic behavior in large structures. Ground motion produced by underground nuclear explosions can produce inelastic earthquake-like effects in large structures and could be used for testing large structures in the inelastic response regime. The Nevada Test Site is a feasible earthquake simulator for testing large structures

  1. Experimental study on the influence of chemical sensitizer on pressure resistance in deep water of emulsion explosives

    Science.gov (United States)

    Liu, Lei; zhang, Zhihua; Wang, Ya; Qin, hao

    2018-03-01

    The study on the pressure resistance performance of emulsion explosives in deep water can provide theoretical basis for underwater blasting, deep-hole blasting and emulsion explosives development. The sensitizer is an important component of emulsion explosives. By using reusable experimental devices to simulate the charge environment in deep water, the influence of the content of chemical sensitizer on the deep-water pressure resistance performance of emulsion explosives was studied. The experimental results show that with the increasing of the content of chemical sensitizer, the deep-water pressure resistance performance of emulsion explosives gradually improves, and when the pressure is fairly large, the effect is particularly pronounced; in a certain range, with the increase of the content of chemical sensitizer, that emulsion explosives’ explosion performance also gradually improve, but when the content reaches a certain value, the explosion properties declined instead; under the same emulsion matrix condition, when the content of NANO2 is 0.2%, that the emulsion explosives has good resistance to water pressure and good explosion properties. The correctness of the results above was testified in model blasting.

  2. Optical detection of explosives: spectral signatures for the explosive bouquet

    Science.gov (United States)

    Osborn, Tabetha; Kaimal, Sindhu; Causey, Jason; Burns, William; Reeve, Scott

    2009-05-01

    Research with canines suggests that sniffer dogs alert not on the odor from a pure explosive, but rather on a set of far more volatile species present in an explosive as impurities. Following the explosive trained canine example, we have begun examining the vapor signatures for many of these volatile impurities utilizing high resolution spectroscopic techniques in several molecular fingerprint regions. Here we will describe some of these high resolution measurements and discuss strategies for selecting useful spectral signature regions for individual molecular markers of interest.

  3. The research on x-ray nondestructive testing and image processing technology of explosive components

    International Nuclear Information System (INIS)

    Shi, C.; Zhai, X.; Liu, Z.; Lin, H.

    2004-01-01

    The explosive components will inevitably produce defects such as impurity, crack and degumming during production and storage, therefore the inside substance of the explosive components must be examined and the findings concerned must be identified and estimated in order to ensure the quality and service life of the explosive components. Firstly, some analyses are conducted on the usual X-ray NDT system theory, and the simulation explosive component is made with some pre-built defects such as debonding, cracks, blow holes, impurities, and non-uniform density. The image testing system most fit for the explosive components is established. Secondly, the ways of X-ray digital image processing are discussed; the obtained images are enhanced and restored through the self-accommodating build-up arithmetic and proper restoring methods. By means of the results of the overall comparison and analysis of the digital image processing technology, it is clearly indicated that it is feasible to use X-ray digital-imaging ways to carry out the NDT of explosive components and identify the inside defects. (author)

  4. Simulation of the vibrational chemistry and the infrared signature induced by a Sprite streamer in the mesosphere

    Science.gov (United States)

    Romand, F.; Payan, S.; Croize, L.

    2017-12-01

    Since their first observation in 1989, effect of TLEs on the atmospheric composition has become an open and important question. The lack of suitable experimental data is a shortcoming that hampers our understanding of the physics and chemistry induced by these effects. HALESIS (High-Altitude Luminous Events Studied by Infrared Spectro-imagery) is a future experiment dedicated to the measurement of the atmospheric perturbation induced by a TLE in the minutes following its occurrence, from a stratospheric balloon flying at an altitude of 25 km to 40 km. This work aims to quantify the local chemical impact of sprites in the stratosphere and mesosphere. In this paper, we will present the development of a tool which simulates (i) the impact of a sprite on the vibrational chemistry, (ii) the resulting infrared signature and (iii) the propagation of this signature through the atmosphere to an observer. First the Non Local Thermodynamic Equilibrium populations of a background atmosphere were computed using SAMM2 code. The initial thermodynamic and chemical description of atmosphere comes from the Whole Atmosphere community Climate Model (WACCM). Then a perturbation was applied to simulate a sprite. Chemistry due to TLEs was computed using Gordillo-Vazquez kinetic model. Rate coefficients that depend on the electron energy distribution function were calculated from collision cross-section data by solving the electron Boltzmann equation (BE). Time evolutions of the species densities and of vibrational populations in the non-thermal plasma consecutive to sprite discharge were simulated using the computer code ZDPlasKin (S. Pancheshn et al.). Finally, the resulting infrared signatures were propagated from the disturbed area through the atmosphere to an instrument placed in a limb line of sight using a line by line radiative transfer model. We will conclude that sprite could produce a significant infrared signature that last a few tens of seconds after the visible flash.

  5. The control and prevention of dust explosions

    Energy Technology Data Exchange (ETDEWEB)

    1982-01-01

    Papers presented discussed: explosion characteristics and hybrid mixtures explosion characteristics and influencing factors, propagation of dust explosions in ducts, prevention of dust explosions, desensitization, explosion-proof type of construction, explosion pressure relief, optical flame barriers, slide-valves for explosion protection, Ventex explosion barrier valves, grinding and mixing plants, spray driers, dust explosions in silos, and explosion-proof bucket elevators. One paper has been abstracted separately.

  6. BWR water chemistry impurity studies

    International Nuclear Information System (INIS)

    Ljungberg, L.G.; Korhonen, S.; Renstroem, K.; Hofling, C.G.; Rebensdorff, B.

    1990-03-01

    Laboratory studies were made on the effect of water impurities on environmental cracking in simulated BWR water of stainless steel, low alloy steel and nickel-base alloys. Constant elongation rate tensile (CERT) tests were run in simulated normal water chemistry (NWC), hydrogen water chemistry (HWC), or start-up environment. Sulfate, chloride and copper with chloride added to the water at levels of a fraction of a ppM were found to be extremely deleterious to all kinds of materials except Type 316 NG. Other detrimental impurities were fluoride, silica and some organic acids, although acetic acid was beneficial. Nitrate and carbon dioxide were fairly inoccuous. Corrosion fatigue and constant load tests on compact tension specimens were run in simulated normal BWR water chemistry (NWC) or hydrogen water chemistry (HWC), without impurities or with added sulfate or carbon dioxide. For sensitized Type 304 SS in NWC, 0.1 ppM sulfate increased crack propagation rates in constant load tests by up to a factor of 100, and in fatigue tests up to a factor of 10. Also, cracking in Type 316 nuclear grade SS and Alloy 600 was enhanced, but to a smaller degree. Carbon dioxide was less detrimental than sulfate. 3 figs., 4 tabs

  7. A systematic study of the explosion energy issue in core collapse supernova theory

    Science.gov (United States)

    Yamamoto, Yu

    2016-06-01

    Massive stars with main sequence masses greater than 8 solar mass (Msun) the main target of CCSNe researches. According to initial mass function (IMF) they occupy about 15As a matter of fact, supernova theorists have failed to reproduce this energetic stellar explosion for about a half century because micro and macro physics are highly complex and are mutual influenced. The theoretical investigation of the explosion mechanism is based on numerical simulations, which will ultimately require computational sources of exsa scales. With recent remarkable developments both in hardware and software, however, more realistic physics are incorporated and research group are beginning to overcome the difficulties, reporting successful explosions in their numerical models. The successful is still partial, unfortunately, since in the most of the cases the explosion energy hardly reaches the typical value (10^51erg). What is worse other groups found no explosion for almost same setups. The robust explosion mechanism has not yet been ascertained and is still a remaining issue. The purpose of this paper is to study how far our understanding of "neutrino heating mechanism", the current paradigm, has reached, or put another way, to expose what kind of physics are still missing to explain observations , such as explosion energy and nickel mass. As already remarked the physics in CCSNe are quite complicated with extremely high Reynolds number, highly uncertain equation of state (EOS) at supra-nuclear densities, copious neutrinos not in thermal nor chemical equilibrium with matter normally. I believe that it is justified to devote a somewhat large number of pages to the introduction. It will be also helpful for understanding the motivation of this paper. Starting with evidence from supernova light curves I will then move to the basics idea of neutrino heating mechanism and summarize some recent developments in various micro and macro physics. Key factors in the theory of massive

  8. Rock strength under explosive loading

    International Nuclear Information System (INIS)

    Rimer, N.; Proffer, W.

    1993-01-01

    This presentation emphasizes the importance of a detailed description of the nonlinear deviatoric (strength) response of the surrounding rock in the numerical simulation of underground nuclear explosion phenomenology to the late times needed for test ban monitoring applications. We will show how numerical simulations which match ground motion measurements in volcanic tuffs and in granite use the strength values obtained from laboratory measurements on small core samples of these rocks but also require much lower strength values after the ground motion has interacted with the rock. The underlying physical mechanisms for the implied strength reduction are not yet well understood, and in fact may depend on the particular rock type. However, constitutive models for shock damage and/or effective stress have been used successfully at S-Cubed in both the Geophysics Program (primarily for DARPA) and the Containment Support Program (for DNA) to simulate late time ground motions measured at NTS in many different rock types

  9. Chernobyl explosion bombshell

    International Nuclear Information System (INIS)

    Martin, S.; Arnott, D.

    1988-01-01

    It is suggested that the explosion at the Chernobyl-4 reactor in April 1986 was a nuclear explosion. The evidence for this is examined. The sequence of events at Chernobyl is looked at to see if the effects were like those from a nuclear explosion. The question of whether a United Kingdom reactor could go prompt critical is discussed. It is concluded that prompt criticality excursions are possible, but the specific Chernobyl sequence is impossible. (UK)

  10. Experimental simulation of gas cloud explosion effects on a reactor containment

    International Nuclear Information System (INIS)

    Thor, H.J.

    1983-01-01

    The loading of a nuclear power plant by pressure waves from an exploding gas cloud involves problems of large complexity. Therefore guidelines have been issued, containing conservative estimates, for the case of a deflagrating gas cloud to facilitate the design praxis. The actual load due to pressure waves depends on the type of the explosion. A deflagration with its slow burning speed is characterized by a pressure pulse with relatively long duration and low amplitude, whereas a detonation causes a blast wave with a sudden pressure rise and high peak value but short period. In the deflagration process turbulent flame acceleration also may lead to a blast wave type pressure pulse. Results of experiments are presented carried out to evaluate the loading of a nuclear power plant by pressure pulses of both characteristics. The configuration of the model and the pulse duration are scaled 1/200. An intricate wave pattern is caused by the reflections and diffractions of the pressure waves due to the complex layout. Many parameters are involved which depend on the type of explosion, e.g. peak pressure, duration of positive and negative phase, rise time. (orig./WL)

  11. Nanosecond laser ablation of target Al in a gaseous medium: explosive boiling

    Science.gov (United States)

    Mazhukin, V. I.; Mazhukin, A. V.; Demin, M. M.; Shapranov, A. V.

    2018-03-01

    An approximate mathematical description of the processes of homogeneous nucleation and homogeneous evaporation (explosive boiling) of a metal target (Al) under the influence of ns laser radiation is proposed in the framework of the hydrodynamic model. Within the continuum approach, a multi-phase, multi-front hydrodynamic model and a computational algorithm are designed to simulate nanosecond laser ablation of the metal targets immersed in gaseous media. The proposed approach is intended for modeling and detailed analysis of the mechanisms of heterogeneous and homogeneous evaporation and their interaction with each other. It is shown that the proposed model and computational algorithm allow modeling of interrelated mechanisms of heterogeneous and homogeneous evaporation of metals, manifested in the form of pulsating explosive boiling. Modeling has shown that explosive evaporation in metals is due to the presence of a near-surface temperature maximum. It has been established that in nanosecond pulsed laser ablation, such exposure regimes can be implemented in which phase explosion is the main mechanism of material removal.

  12. THREE-DIMENSIONAL CORE-COLLAPSE SUPERNOVA SIMULATED USING A 15 M{sub ⊙} PROGENITOR

    Energy Technology Data Exchange (ETDEWEB)

    Lentz, Eric J.; Mezzacappa, Anthony; Harris, J. Austin; Yakunin, Konstantin N. [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996-1200 (United States); Bruenn, Stephen W. [Department of Physics, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431-0991 (United States); Hix, W. Raphael [Physics Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6354 (United States); Messer, O. E. Bronson [National Center for Computational Sciences, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6164 (United States); Endeve, Eirik [Computer Science and Mathematics Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6164 (United States); Blondin, John M. [Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States); Marronetti, Pedro, E-mail: elentz@utk.edu [Physics Division, National Science Foundation, Arlington, VA 22207 (United States)

    2015-07-10

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

  13. Directional excitation of Rg due to ripple-fired explosions: 2-Dimensional finite-difference simulations

    International Nuclear Information System (INIS)

    Jih, Rong-Song

    1993-01-01

    A major issue for the Non-Proliferation Treaty is the discrimination of large chemical explosions from possible clandestine or small nuclear tests. Unless discrimination is possible, the numerous mining blasts could give ample opportunity for concealing clandestine tests. Ripple-fired explosions are commonly used to fragment rocks during quarry and open-pit mining. The periodicity inherent in the ripple firing could produce a seismic reinforcement at the frequency of the delay between shots or rows. It has been suggested that the convolution of a single explosion with a comb function of variable spacing and variable amplitude can be used to model the distinctive signature of ripple firing. Baumgardt and Ziegler (1988) delicately demonstrated that the incoherent array-stack spectra can be used to identify some multiple shots recorded at NORSAR. By superpositioning the waveform due to a single shot with proper time delay, they were able to model the source multiplicity under the assumption that the spatial spreading of the shots is negligible with respect to the distance to the receiver. The work by Stump et al. successfully characterized the major features of the wavefield due to ripple firings at near-source ranges

  14. Analysis of the Effect of Explosion on Altering the Tensions and Strains in Buried Water Pipes

    Directory of Open Access Journals (Sweden)

    Ebrahim Alamatian

    2015-09-01

    Full Text Available Pipelines that are buried in ground are used for transference of water and energy sources. These lines are considered infrastructures and have a high importance. In this paper behavior of soil and pipes are simulated using the finite-element based software ABAQUS, and effect of blast wave on the amount of tension and displacement of a pipe is investigated. The simulations are run for the pipe’s substance, burial depth, dimension, and also the intensity and situation of the explosion. AUTODYN software is used for evaluation of blast wave’s power. Simulation results show the positive effect of increasing the pipe’s dimension and burial depth on reducing the destruction caused by explosion.

  15. A study on vapor explosions

    International Nuclear Information System (INIS)

    Takagi, N.; Shoji, M.

    1979-01-01

    An experimental study was carried out for vapor explosions of molten tin falling in water. For various initial metal temperatures and subcooling of water, transient pressure of the explosions, relative frequency of the explosions and the position where the explosions occur were measured in detail. The influence of ambient pressure was also investigated. From the results, it was concluded that the vapor explosion is closely related to the collapse of a vapor film around the molten metal. (author)

  16. Theoretical work on melt-coolant interactions (steam explosions)

    International Nuclear Information System (INIS)

    Arnecke, G.; Jacobs, H.; Stehle, B.; Thurnay, K.; Vaeth, L.; Lummer, M.

    1995-01-01

    The code IVA3 is used for modelling the physical processes related to steam explosions, i.e. the premixing phase preceding the explosion as well as the explosion itself. This code has been replaced by the updated version IVA-KA in May 1994, which encompasses all model and code improvements performed till the beginning of 1994. The following further work on and with IVA-KA has been performed: 1. Inclusion of friction at inner and outer walls, improvement on the drag model, improvement of boundary conditions for outgoing flow, optional inclusion of improved water material data, improvement of the numerical procedure, correction of coding errors. 2. Three FARO-experiments (investigating the behaviour of molten material falling into water) were recalculated with IVA-KA. The time dependent pressure increase is reproduced very well for one experiment, but is not quite satisfactory for a second one. The third one cannot be simulated satisfactorily because of the presence of metallic zirconium in the melt, which is not being modelled by IVA-KA at present. 3. One PREMIX-experiment (similar to FARO, but at 1 bar ambient pressure and with smaller amounts of melt) is also being analyzed with IVA-KA. First results show a good representation of the material distribution during the penetration of the melt into the water. 4. One of the first two QUEOS-experiments performed at KfK has been simulated with IVA-KA. Some results are well reproduced by IVA-KA, but there may be a deficiency of the drag laws. (orig./HP)

  17. High-Speed Imaging of Explosive Droplet Boiling at the Superheat Limit

    Science.gov (United States)

    Ferris, F. Robert; Hermanson, Jim; Asadollahi, Arash; Esmaeeli, Asghar

    2017-11-01

    The explosive boiling processes of droplets of diethyl ether (1-2 mm in diameter) at the superheat limit were examined both experimentally and computationally. Experimentally, droplet explosion was studied using a heated bubble column to bring the test droplet to the superheat limit. The droplet fluid was diethyl ether (superheat limit 147 C at 1 bar) with immiscible glycerol employed as the heated host fluid. Tests were carried out at pressures between 0.5 and 4 bar absolute. The pressure rise associated with the explosive boiling event was captured using a piezoelectric quartz pressure transducer with a 1 MHz DAQ system. High-speed imaging of the interfacial behavior during explosive boiling was performed using a Phantom v12.1 camera at a frame rate of up to one million frames per second with the droplets illuminated by diffuse back-lighting. The imaging reveals features of the Rayleigh-Taylor instability at the vapor-liquid interface resulting from the unstable boiling process. Computationally, Direct Numerical Simulations are performed at Southern Illinois University Carbondale to compliment the experimental tests. NSF Award Number 1511152.

  18. Aspects regarding explosion risk assessment

    Directory of Open Access Journals (Sweden)

    Părăian Mihaela

    2017-01-01

    Full Text Available Explosive risk occurs in all activities involving flammable substances in the form of gases, vapors, mists or dusts which, in mixture with air, can generate an explosive atmosphere. As explosions can cause human losses and huge material damage, the assessment of the explosion risk and the establishment of appropriate measures to reduce it to acceptable levels according to the standards and standards in force is of particular importance for the safety and health of people and goods.There is no yet a recognized method of assessing the explosion risk, but regardless of the applied method, the likelihood of an explosive atmosphere occurrence has to be determined, together with the occurrence of an efficient ignition source and the magnitude of foreseeable consequences. In assessment processes, consequences analysis has a secondary importance since it’s likely that explosions would always involve considerable damage, starting from important material damages and up to human damages that could lead to death.The purpose of the work is to highlight the important principles and elements to be taken into account for a specific risk assessment. An essential element in assessing the risk of explosion in workplaces where explosive atmospheres may occur is technical installations and personal protective equipment (PPE that must be designed, manufactured, installed and maintained so that they cannot generate a source of ignition. Explosion prevention and protection requirements are governed by specific norms and standards, and a main part of the explosion risk assessment is related to the assessment of the compliance of the equipment / installation with these requirements.

  19. Numerical modelling of the effect of using multi-explosives on the explosive forming of steel cones

    OpenAIRE

    De Vuyst, T; Kong, K; Djordjevic, N; Vignjevic, R; Campbell, JC; Hughes, K

    2016-01-01

    Modelling and analysis of underwater explosive forming process by using FEM and SPH formulation is presented in this work. The explosive forming of a steel cone is studied. The model setup includes a low carbon steel plate, plate holder, forming die as well as water and C4 explosive. The effect of multiple explosives on rate of targets deformation has been studied. Four different multi-explosives models have been developed and compared to the single explosive model. The formability of the ste...

  20. Insights into explosion dynamics at Stromboli in 2009 from ash samples collected in real-time

    Science.gov (United States)

    Taddeucci, J.; Lautze, N.; Andronico, D.; D'Auria, L.; Niemeijer, A.; Houghton, B.; Scarlato, P.

    2012-04-01

    Rapid characterization of tephra during explosive eruptions can provide valuable insights into eruptive mechanisms, also integrating other monitoring systems. Here we reveal a perspective on Stromboli's conduit processes by linking ash textures to geophysical estimates of eruption parameters of observed explosions. A three day campaign at Stromboli was undertaken by Italy's Istituto Nazionale di Geofisica e Vulcanologia (INGV) in October 2009. At this time activity was moderately intense, with an average 4 to 5, both ash-rich and ash-poor, explosions per hour at each the SW and NE vents. A total of fifteen ash samples were collected in real time. We used binocular and scanning electron microscopes to analyze the components, grain size and morphology distributions, and surface chemistry of ash particles within eight selected samples. In addition, the INGV monitoring network provided visual, thermal, and seismic information on the explosions that generated the sampled ash. In each sample, the proportion of fluidal, glassy sideromelane (as opposed to blocky, microcrystalline tachylite plus lithics), the degree of "chemical freshness" (as opposed to chemical alteration), and the average size of particles appear to correlate directly with the maximum height and the seismic amplitude of the corresponding explosion, and inversely correlate with the amount of ash erupted, as estimated by monitoring videos. These observations suggest that more violent explosions (i.e., those driven by the release of larger and more pressurized gas volumes) produce ash via the fragmentation of hotter, more fluid magma, while weaker ones mostly erupt ash-sized particles derived by the fragmentation of colder magma and incorporation of conduit wall debris. The formation of fluidal ash particles (up to Pele's hairs) requires aerodynamic deformation of a relatively low-viscosity magma, in agreement with the strong acceleration imposed upon fragmented magma clots by the rapid expansion of

  1. Numerical investigation and Uncertainty Quantification of the Impact of the geological and geomechanical properties on the seismo-acoustic responses of underground chemical explosions

    Science.gov (United States)

    Ezzedine, S. M.; Pitarka, A.; Vorobiev, O.; Glenn, L.; Antoun, T.

    2017-12-01

    We have performed three-dimensional high resolution simulations of underground chemical explosions conducted recently in jointed rock outcrop as part of the Source Physics Experiments (SPE) being conducted at the Nevada National Security Site (NNSS). The main goal of the current study is to investigate the effects of the structural and geomechanical properties on the spall phenomena due to underground chemical explosions and its subsequent effect on the seismo-acoustic signature at far distances. Two parametric studies have been undertaken to assess the impact of different 1) conceptual geological models including a single layer and two layers model, with and without joints and with and without varying geomechanical properties, and 2) depth of bursts of the chemical explosions and explosion yields. Through these investigations we have explored not only the near-field response of the chemical explosions but also the far-field responses of the seismic and the acoustic signatures. The near-field simulations were conducted using the Eulerian and Lagrangian codes, GEODYN and GEODYN -L, respectively, while the far-field seismic simulations were conducted using the elastic wave propagation code, WPP, and the acoustic response using the Kirchhoff-Helmholtz-Rayleigh time-dependent approximation code, KHR. Though a series of simulations we have recorded the velocity field histories a) at the ground surface on an acoustic-source-patch for the acoustic simulations, and 2) on a seismic-source-box for the seismic simulations. We first analyzed the SPE3 experimental data and simulated results, then simulated SPE4-prime, SPE5, and SPE6 to anticipate their seismo-acoustic responses given conditions of uncertainties. SPE experiments were conducted in a granitic formation; we have extended the parametric study to include other geological settings such dolomite and alluvial formations. These parametric studies enabled us 1) investigating the geotechnical and geophysical key parameters

  2. Combustion and smoke formation following exposure of actinide metals to explosions

    International Nuclear Information System (INIS)

    Luna, R.E.; Church, H.W.; Elrick, R.M.; Parker, D.R.; Nelson, L.S.

    1976-01-01

    Results from the plutonium aerosol generation experiment (PAGE) program studies indicate that: (1) Significant quantities of metal-bearing aerosols are likely to be formed in an accidental high explosive detonation of a nuclear weapon. Although the explosive charge-to-metal ratio has been reduced in modern weapons, considerable inhalation hazard is still expected due to increased shrapnel formation and streamer combustion. (2) Close-in shrapnel particle sizes and velocities can be estimated by impact sampling techniques. (3) Uranium droplets are a very accurate simulant of plutonium droplets from the standpoint of combustion-related phenomena but do not seem to simulate either the total quantity of aerosol formed from plutonium droplets or its time-dependent generation pattern very well. This is due primarily to the large effect of the explosion of the burning uranium droplets on total aerosol formation which is not observed in the case of plutonium, even though more aerosol is produced per unit time during the actual combustion itself. (4) The formation of chain-like plutonium aerosols from the droplets produced during streamer combustion is expected to produce an unusually active material from the standpoint of inhalation into the lung and ultimate translocation in the body. 16 figures

  3. The quantitative studies on gas explosion suppression by an inert rock dust deposit.

    Science.gov (United States)

    Song, Yifan; Zhang, Qi

    2018-07-05

    The traditional defence against propagating gas explosions is the application of dry rock dust, but not much quantitative study on explosion suppression of rock dust has been made. Based on the theories of fluid dynamics and combustion, a simulated study on the propagation of premixed gas explosion suppressed by deposited inert rock dust layer is carried out. The characteristics of the explosion field (overpressure, temperature, flame speed and combustion rate) at different deposited rock dust amounts are investigated. The flame in the pipeline cannot be extinguished when the deposited rock dust amount is less than 12 kg/m 3 . The effects of suppressing gas explosion become weak when the deposited rock dust amount is greater than 45 kg/m 3 . The overpressure decreases with the increase of the deposited rock dust amounts in the range of 18-36 kg/m 3 and the flame speed and the flame length show the same trends. When the deposited rock dust amount is 36 kg/m 3 , the overpressure can be reduced by 40%, the peak flame speed by 50%, and the flame length by 42% respectively, compared with those of the gas explosion of stoichiometric mixture. In this model, the effective raised dust concentrations to suppress explosion are 2.5-3.5 kg/m 3 . Copyright © 2018 Elsevier B.V. All rights reserved.

  4. JASMINE-pro: A computer code for the analysis of propagation process in steam explosions. User's manual

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yanhua; Nilsuwankosit, Sunchai; Moriyama, Kiyofumi; Maruyama, Yu; Nakamura, Hideo; Hashimoto, Kazuichiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2000-12-01

    A steam explosion is a phenomenon where a high temperature liquid gives its internal energy very rapidly to another low temperature volatile liquid, causing very strong pressure build up due to rapid vaporization of the latter. In the field of light water reactor safety research, steam explosions caused by the contact of molten core and coolant has been recognized as a potential threat which could cause failure of the pressure vessel or the containment vessel during a severe accident. A numerical simulation code JASMINE was developed at Japan Atomic Energy Research Institute (JAERI) to evaluate the impact of steam explosions on the integrity of reactor boundaries. JASMINE code consists of two parts, JASMINE-pre and -pro, which handle the premixing and propagation phases in steam explosions, respectively. JASMINE-pro code simulates the thermo-hydrodynamics in the propagation phase of a steam explosion on the basis of the multi-fluid model for multiphase flow. This report, 'User's Manual', gives the usage of JASMINE-pro code as well as the information on the code structures which should be useful for users to understand how the code works. (author)

  5. Analysis of Nitro-aromatic and Nitramine Explosives by Atmospheric Pressure Chemical Ionization / High Performance Liquid Chromatography / Mass Spectrometry / Mass Spectrometry

    International Nuclear Information System (INIS)

    Hicks, B.J.; Han, W.; Robben, J.R.

    2009-01-01

    This procedure is capable of separating and quantifying twenty-nine high explosives and internal surrogates with a single injection. After the initial preparation step, the sample is introduced to the high performance liquid chromatograph for target separation, ionized by atmospheric pressure chemical ionization and the explosives of interest are isolated / quantified by mass spectrometry / mass spectrometry. Concentrations of the target explosives are measured relative to the response of both internal and external standard concentrations. A C-18 reverse phase high performance liquid chromatograph column is used for separation. Ionization is performed using both positive and negative atmospheric pressure chemical ionization resulting in a molecular ion with little fragmentation. These ions are isolated at the first quadrupole of the mass spectrometer, dissociated by collision with argon in the collision cell and the resulting daughter ions are isolated at the second quadrupole. These daughter ions then reach the detector where they are quantified. To date this procedure represents the most thorough high performance liquid chromatography / mass spectrometry / mass spectrometry explosives analysis available in the environmental chemistry market. (authors)

  6. Installation for low temperature vapor explosion experiment

    International Nuclear Information System (INIS)

    Nilsuwankosit, Sunchai; Archakositt, Urith

    2000-01-01

    A preparation for the experiment on the low temperature vapor explosion was planned at the department of Nuclear Technology, Chulalongkorn University, Thailand. The objective of the experiment was to simulate the interaction between the molten fuel and the volatile cooling liquid without resorting to the high temperature. The experiment was expected to involve the injection of the liquid material at a moderate temperature into the liquid material with the very low boiling temperature in order to observe the level of the pressurization as a function of the temperatures and masses of the applied materials. For this purpose, the liquid nitrogen and the water were chosen as the coolant and the injected material for this experiment. Due to the size of the installation and the scale of the interaction, only lumped effect of various parameters on the explosion was expected from the experiment at this initial stage. (author)

  7. Serious Gaming for Improvised Explosive Device Neutralization Training

    Directory of Open Access Journals (Sweden)

    Chan Christopher C.K.

    2016-01-01

    Full Text Available An improvised explosive device (IED is a “homemade” bomb intended to cause great harm when it explodes. The public safety task of identifying and neutralizing IEDs falls to military and police services often called explosive disposal units (EDU who act to neutralize the threat associated with the IED either rendering it inoperable or destroying it safely. EDUs train in various aspects of explosive handling and investigation but are limited in the tools available for safely analyzing real world bombs. This paper describes a game based approach to IED training that employs an interactive 3D simulation to spatially identify key IED components of interest. We give an example of how this approach might be used and provide a preliminary evaluation of its potential effectiveness. We employ images formed from a Digital Imaging and Communications in Medicine (DICOM system captured using Magnetic Resonance Imaging (MRI technology to a virtual IED in a game. Empirical evaluation and EDU testimony suggest accurate representation of the IED and the potential efficacy of the proposed approach for successfully identifying components in the bomb for the purposes of EDU training.

  8. Radioactive Beam Measurements to Probe Stellar Explosions

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Michael Scott [ORNL

    2010-01-01

    Unique beams of unstable nuclei from the Holi eld Radioactive Ion Beam Facility at Oak Ridge National Laboratory are being used to measure the thermonuclear reactions that occur in novae, X-ray bursts, and supernovae. The astrophysical impact of these measurements is determined by synergistic nuclear data evaluations and element synthesis calculations. Results of recent measurements and explosion simulations are brie y described, along with future plans and software research tools for the community.

  9. Dimethylsulfide Chemistry: Annual, Seasonal, and Spatial Impacts on Sulfate

    Science.gov (United States)

    We incorporated oceanic emissions and atmospheric chemistry of dimethylsulfide (DMS) into the hemispheric Community Multiscale Air Quality model and performed annual model simulations without and with DMS chemistry. The model without DMS chemistry predicts higher concentrations o...

  10. EXPLOSION OF ANNULAR CHARGE ON DUSTY SURFASE

    Directory of Open Access Journals (Sweden)

    A. Levin Vladimir

    2017-01-01

    Full Text Available This problem is related to the safety problem in the area of forest fires. It is well known that is possible to extinguish a fire, for example, by means of a powerful air stream. Such flow arises from the explosive shock wave. To enhance the im- pact of the blast wave can be used an explosive charge of annular shape. The shock wave, produced by the explosion, in- creased during moves to the center and can serve as a means of transportation dust in the seat of the fire. In addition, emerging after the collapse of a converging shock wave strong updraft can raise dust on a greater height and facilitate fire extinguishing, precipitating dust over a large area. This updraft can be dangerous for aircraft that are in the sky above the fire. To determine the width and height of the danger zone performed the numerical simulation of the ring of the explosion and the subsequent movement of dust and gas mixtures. The gas is considered ideal and perfect. The explosion is modeled as an instantaneous increase in the specific internal energy in an annular zone on the value of the specific heat of explosives. The flow is consid- ered as two-dimensional, and axisymmetric. The axis of symmetry perpendicular to the Earth surface. This surface is considered to be absolutely rigid and is considered as the boundary of the computational domain. On this surface is exhibited the condition of no motion. For the numerical method S. K. Godunov is used a movable grid. One system of lines of this grid is moved in accordance with movement of the shock wave. Others lines of this grid are stationary. The calculations were per- formed for different values of the radii of the annular field and for different sizes of rectangular cross-sectional of the annular field. Numerical results show that a very strong flow is occurring near the axis of symmetry and the particles rise high above the surface. These calculations allow us to estimate the sizes of the zone of danger in specific

  11. Chemistry Notes

    Science.gov (United States)

    School Science Review, 1972

    1972-01-01

    Short articles on the kinetics of the hydrogen peroxide-iodide ion reaction, simulation of fluidization catalysis, the use of Newman projection diagrams to represent steric relationships in organic chemistry, the use of synthetic substrates for proteolytic enzyme reactions, and two simple clock reactions"--hydrolysis of halogenoalkanes and…

  12. General phenomenology of underground nuclear explosions

    International Nuclear Information System (INIS)

    Derlich, S.; Supiot, F.

    1969-01-01

    An essentially qualitatively description is given of the phenomena related to underground nuclear explosions (explosion of a single unit, of several units in line, and simultaneous explosions). In the first chapter are described the phenomena which are common to contained explosions and to explosions forming craters (formation and propagation of a shock-wave causing the vaporization, the fusion and the fracturing of the medium). The second chapter describes the phenomena related to contained explosions (formation of a cavity with a chimney). The third chapter is devoted to the phenomenology of test explosions which form a crater; it describes in particular the mechanism of formation and the different types of craters as a function of the depth of the explosion and of the nature of the ground. The aerial phenomena connected with explosions which form a crater: shock wave in the air and focussing at a large distance, and dust clouds, are also dealt with. (authors) [fr

  13. Proceedings of the CSNI specialist meeting on interaction of fire and explosion with ventilation systems in nuclear facilities. Volume I

    International Nuclear Information System (INIS)

    1983-10-01

    Separate abstracts were prepared for the papers presented in the following areas: (1) fire and explosion perspectives; (2) fire, explosion, and radioactive source terms; and (3) development and verification of codes (a) mathematical and computer simulation and (b) analytical and experimental comparisons

  14. Description and validation of ERAD: An atmospheric dispersion model for high explosive detonations

    Energy Technology Data Exchange (ETDEWEB)

    Boughton, B.A.; DeLaurentis, J.M.

    1992-10-01

    The Explosive Release Atmospheric Dispersion (ERAD) model is a three-dimensional numerical simulation of turbulent atmospheric transport and diffusion. An integral plume rise technique is used to provide a description of the physical and thermodynamic properties of the cloud of warm gases formed when the explosive detonates. Particle dispersion is treated as a stochastic process which is simulated using a discrete time Lagrangian Monte Carlo method. The stochastic process approach permits a more fundamental treatment of buoyancy effects, calm winds and spatial variations in meteorological conditions. Computational requirements of the three-dimensional simulation are substantially reduced by using a conceptualization in which each Monte Carlo particle represents a small puff that spreads according to a Gaussian law in the horizontal directions. ERAD was evaluated against dosage and deposition measurements obtained during Operation Roller Coaster. The predicted contour areas average within about 50% of the observations. The validation results confirm the model`s representation of the physical processes.

  15. Sensitivities of ionic explosives

    Science.gov (United States)

    Politzer, Peter; Lane, Pat; Murray, Jane S.

    2017-03-01

    We have investigated the relevance for ionic explosive sensitivity of three factors that have been demonstrated to be related to the sensitivities of molecular explosives. These are (1) the maximum available heat of detonation, (2) the amount of free space per molecule (or per formula unit) in the crystal lattice and (3) specific features of the electrostatic potential on the molecular or ionic surface. We find that for ionic explosives, just as for molecular ones, there is an overall tendency for impact sensitivity to increase as the maximum detonation heat release is greater. This means that the usual emphasis upon designing explosives with large heats of detonation needs to be tempered somewhat. We also show that a moderate detonation heat release does not preclude a high level of detonation performance for ionic explosives, as was already demonstrated for molecular ones. Relating the free space per formula unit to sensitivity may require a modified procedure for ionic explosives; this will continue to be investigated. Finally, an encouraging start has been made in linking impact sensitivities to the electrostatic potentials on ionic surfaces, although limited so far to ammonium salts.

  16. The development of a ballistic method for simulating fragments from buried explosive devices

    NARCIS (Netherlands)

    Jagt-Deutekom, M.J. van der

    2016-01-01

    No standard scientific methodology currently exists to assess the performance of personal protection equipment (PPE) against secondary debris, such as soil, grit and stones, ejected when a buried improvised explosive device (IED) detonates. Different test methods are used for this evaluation. The

  17. Cell phone explosion.

    Science.gov (United States)

    Atreya, Alok; Kanchan, Tanuj; Nepal, Samata; Pandey, Bhuwan Raj

    2016-03-01

    Cell phone explosions and resultant burn injuries are rarely reported in the scientific literature. We report a case of cell phone explosion that occurred when a young male was listening to music while the mobile was plugged in for charging. © The Author(s) 2015.

  18. Prediction of shock initiation thresholds and ignition probability of polymer-bonded explosives using mesoscale simulations

    Science.gov (United States)

    Kim, Seokpum; Wei, Yaochi; Horie, Yasuyuki; Zhou, Min

    2018-05-01

    The design of new materials requires establishment of macroscopic measures of material performance as functions of microstructure. Traditionally, this process has been an empirical endeavor. An approach to computationally predict the probabilistic ignition thresholds of polymer-bonded explosives (PBXs) using mesoscale simulations is developed. The simulations explicitly account for microstructure, constituent properties, and interfacial responses and capture processes responsible for the development of hotspots and damage. The specific mechanisms tracked include viscoelasticity, viscoplasticity, fracture, post-fracture contact, frictional heating, and heat conduction. The probabilistic analysis uses sets of statistically similar microstructure samples to directly mimic relevant experiments for quantification of statistical variations of material behavior due to inherent material heterogeneities. The particular thresholds and ignition probabilities predicted are expressed in James type and Walker-Wasley type relations, leading to the establishment of explicit analytical expressions for the ignition probability as function of loading. Specifically, the ignition thresholds corresponding to any given level of ignition probability and ignition probability maps are predicted for PBX 9404 for the loading regime of Up = 200-1200 m/s where Up is the particle speed. The predicted results are in good agreement with available experimental measurements. A parametric study also shows that binder properties can significantly affect the macroscopic ignition behavior of PBXs. The capability to computationally predict the macroscopic engineering material response relations out of material microstructures and basic constituent and interfacial properties lends itself to the design of new materials as well as the analysis of existing materials.

  19. A structured approach to forensic study of explosions: The TNO Inverse Explosion Analysis tool

    NARCIS (Netherlands)

    Voort, M.M. van der; Wees, R.M.M. van; Brouwer, S.D.; Jagt-Deutekom, M.J. van der; Verreault, J.

    2015-01-01

    Forensic analysis of explosions consists of determining the point of origin, the explosive substance involved, and the charge mass. Within the EU FP7 project Hyperion, TNO developed the Inverse Explosion Analysis (TNO-IEA) tool to estimate the charge mass and point of origin based on observed damage

  20. The role of fragmentation mechanism in large-scale vapor explosions

    International Nuclear Information System (INIS)

    Liu, Jie

    2003-01-01

    A non-equilibrium, multi-phase, multi-component code PROVER-I is developed for propagation phase of vapor explosion. Two fragmentation models are used. The hydrodynamic fragmentation model is the same as Fletcher's one. A new thermal fragmentation model is proposed with three kinds of time scale for modeling instant fragmentation, spontaneous nucleation fragmentation and normal boiling fragmentation. The role of fragmentation mechanisms is investigated by the simulations of the pressure wave propagation and energy conversion ratio of ex-vessel vapor explosion. The spontaneous nucleation fragmentation results in a much higher pressure peak and a larger energy conversion ratio than hydrodynamic fragmentation. The instant fragmentation gives a slightly larger energy conversion ratio than spontaneous nucleation fragmentation, and the normal boiling fragmentation results in a smaller energy conversion ratio. The detailed analysis of the structure of pressure wave makes it clear that thermal detonation exists only under the thermal fragmentation circumstance. The high energy conversion ratio is obtained in a small vapor volume fraction. However, in larger vapor volume fraction conditions, the vapor explosion is weak. In a large-scale vapor explosion, the hydrodynamic fragmentation is essential when the pressure wave becomes strong, so a small energy conversion ratio is expected. (author)

  1. The associated particle method explosives detection technology

    International Nuclear Information System (INIS)

    An Li; Chen Yuan; Guo Haiping; Zheng Pu; Wang Xinhua; He Tie; Mu Yunfeng; Yang Xiaofei; Zhu Chuanxin

    2009-01-01

    This article introduces the basic principle of associated alpha particles technique for explosives' inspection and the measurement system. The characteristic prompt gamma-rays come from water, graphite, liquid nitrogen, ammonium nitrate, melamine and simulated samples induced by D-T neutron from generator were gained by single alpha particles detector and gamma-ray detector. The complex gamma-ray spectra were deconvolved. The element ratio between the experiment and chemics molecular formula is agreement in 10%. (authors)

  2. Standardized Method for Measuring Collection Efficiency from Wipe-sampling of Trace Explosives.

    Science.gov (United States)

    Verkouteren, Jennifer R; Lawrence, Jeffrey A; Staymates, Matthew E; Sisco, Edward

    2017-04-10

    One of the limiting steps to detecting traces of explosives at screening venues is effective collection of the sample. Wipe-sampling is the most common procedure for collecting traces of explosives, and standardized measurements of collection efficiency are needed to evaluate and optimize sampling protocols. The approach described here is designed to provide this measurement infrastructure, and controls most of the factors known to be relevant to wipe-sampling. Three critical factors (the applied force, travel distance, and travel speed) are controlled using an automated device. Test surfaces are chosen based on similarity to the screening environment, and the wipes can be made from any material considered for use in wipe-sampling. Particle samples of the explosive 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) are applied in a fixed location on the surface using a dry-transfer technique. The particle samples, recently developed to simulate residues made after handling explosives, are produced by inkjet printing of RDX solutions onto polytetrafluoroethylene (PTFE) substrates. Collection efficiency is measured by extracting collected explosive from the wipe, and then related to critical sampling factors and the selection of wipe material and test surface. These measurements are meant to guide the development of sampling protocols at screening venues, where speed and throughput are primary considerations.

  3. Intermittent Explosive Disorder

    Directory of Open Access Journals (Sweden)

    Lut Tamam

    2011-09-01

    Full Text Available Intermittent explosive disorder is an impulse control disorder characterized by the occurrence of discrete episodes of failure to resist aggressive impulses that result in violent assault or destruction of property. Though the prevalence intermittent explosive disorder has been reported to be relatively rare in frontier studies on the field, it is now common opinion that intermittent explosive disorder is far more common than previously thought especially in clinical psychiatry settings. Etiological studies displayed the role of both psychosocial factors like childhood traumas and biological factors like dysfunctional neurotransmitter systems and genetics. In differential diagnosis of the disorder, disorders involving agression as a symptom such as alcohol and drug intoxication, antisocial and borderline personality disorders, personality changes due to general medical conditions and behavioral disorder should be considered. A combination of pharmacological and psychotherapeutic approaches are suggested in the treatment of the disorder. This article briefly reviews the historical background, diagnostic criteria, epidemiology, etiology and treatment of intermittent explosive disorder.

  4. Free radical explosive composition

    Science.gov (United States)

    Walker, Franklin E.; Wasley, Richard J.

    1979-01-01

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

  5. Sub-sonic thermal explosions investigated by radiography

    Energy Technology Data Exchange (ETDEWEB)

    Smilowitz, Laura B [Los Alamos National Laboratory; Henson, Bryan F [Los Alamos National Laboratory; Romero, Jerry J [Los Alamos National Laboratory; Asay, Blaine W [Los Alamos National Laboratory

    2010-01-01

    This paper reviews the past 5 years of experiments utilizing radiographic techniques to study defiagration in thermal explosions in HMX based formulations. Details of triggering and timing synchronization are given. Radiographic images collected using both protons and x-rays are presented. Comparisons of experiments with varying size, case confinement, binder, and synchronization are presented. Techniques for quantifying the data in the images are presented and a mechanism for post-ignition burn propagation in a thermal explosion is discussed. From these experiments, we have observed a mechanism for sub-sonic defiagration with both gas phase convective and solid phase conductive burning. The convective front velocity is directly measured from the radiographic images and consumes only a small fraction of the HE. It lights the HE as it passes beginning the slower solid state conductive burn process. This mechanism is used to create a model to simulate the radiographic results and a comparison will be shown.

  6. Characteristics of a plasma flow field produced by a metal array bridge foil explosion

    Science.gov (United States)

    Junying, WU; Long, WANG; Yase, LI; Lijun, YANG; Manzoor, SULTAN; Lang, CHEN

    2018-07-01

    To improve the energy utilization efficiency of metal bridge foil explosion, and increase the function range of plasmas, array bridge foil explosion experiments with different structures were performed. A Schlieren photographic measurement system with a double-pulse laser source was used to observe the flow field of a bridge foil explosion. The evolution laws of plasmas and shock waves generated by array bridge foil explosions of different structures were analyzed and compared. A multi-phase flow calculation model was established to simulate the electrical exploding process of a metal bridge foil. The plasma equation of state was determined by considering the effect of the changing number of particles and Coulomb interaction on the pressure and internal energy. The ionization degree of the plasma was calculated via the Saha–Eggert equation assuming conditions of local thermal equilibrium. The exploding process of array bridge foils was simulated, and the superposition processes of plasma beams were analyzed. The variation and distribution laws of the density, temperature, pressure, and other important parameters were obtained. The results show that the array bridge foil has a larger plasma jet diameter than the single bridge foil for an equal total area of the bridge foil. We also found that the temperature, pressure, and density of the plasma jet’s center region sharply increase because of the superposition of plasma beams.

  7. Ex-Vessel Steam Explosion Analysis of Central Melt Pour Scenario

    International Nuclear Information System (INIS)

    Ursic, M.; Leskovar, M.

    2008-01-01

    gained at 2 bar primary system overpressure and water sub-cooling of 50 degree C. The purpose of the work presented in the paper is to perform a detailed analysis of the central melt pour scenario at 2 bar primary system overpressure and water sub-cooling of 50 degree C, where the strongest steam explosion occurred. The steam explosion analysis will be performed with the computer code MC3D, which is build mainly for the simulation of the complex FCI phenomena. The MC3D is being developed by IRSN, France. The reasons for the obtained so high pressure loads during the steam explosion in the selected scenario will be highlighted and discussed in details.(author)

  8. Implications of Lagrangian transport for coupled chemistry-climate simulations

    Science.gov (United States)

    Stenke, A.; Dameris, M.; Grewe, V.; Garny, H.

    2008-10-01

    For the first time a purely Lagrangian transport algorithm is applied in a fully coupled chemistry-climate model (CCM). We use the Lagrangian scheme ATTILA for the transport of water vapour, cloud water and chemical trace species in the ECHAM4.L39(DLR)/CHEM (E39C) CCM. The advantage of the Lagrangian approach is that it is numerically non-diffusive and therefore maintains steeper and more realistic gradients than the operational semi-Lagrangian transport scheme. In case of radiatively active species changes in the simulated distributions feed back to model dynamics which in turn affect the modelled transport. The implications of the Lagrangian transport scheme for stratospheric model dynamics and tracer distributions in the upgraded model version E39C-ATTILA (E39C-A) are evaluated by comparison with observations and results of the E39C model with the operational semi-Lagrangian advection scheme. We find that several deficiencies in stratospheric dynamics in E39C seem to originate from a pronounced modelled wet bias and an associated cold bias in the extra-tropical lowermost stratosphere. The reduction of the simulated moisture and temperature bias in E39C-A leads to a significant advancement of stratospheric dynamics in terms of the mean state as well as annual and interannual variability. As a consequence of the favourable numerical characteristics of the Lagrangian transport scheme and the improved model dynamics, E39C-A generally shows more realistic stratospheric tracer distributions: Compared to E39C high stratospheric chlorine (Cly) concentrations extend further downward and agree now well with analyses derived from observations. Therefore E39C-A realistically covers the altitude of maximum ozone depletion in the stratosphere. The location of the ozonopause, i.e. the transition from low tropospheric to high stratospheric ozone values, is also clearly improved in E39C-A. Furthermore, the simulated temporal evolution of stratospheric Cly in the past is

  9. Simulations of physics and chemistry of polar stratospheric clouds with a general circulation model

    Energy Technology Data Exchange (ETDEWEB)

    Buchholz, J.

    2005-04-20

    A polar stratospheric cloud submodel has been developed and incorporated in a general circulation model including atmospheric chemistry (ECHAM5/MESSy). The formation and sedimentation of polar stratospheric cloud (PSC) particles can thus be simulated as well as heterogeneous chemical reactions that take place on the PSC particles. For solid PSC particle sedimentation, the need for a tailor-made algorithm has been elucidated. A sedimentation scheme based on first order approximations of vertical mixing ratio profiles has been developed. It produces relatively little numerical diffusion and can deal well with divergent or convergent sedimentation velocity fields. For the determination of solid PSC particle sizes, an efficient algorithm has been adapted. It assumes a monodisperse radii distribution and thermodynamic equilibrium between the gas phase and the solid particle phase. This scheme, though relatively simple, is shown to produce particle number densities and radii within the observed range. The combined effects of the representations of sedimentation and solid PSC particles on vertical H{sub 2}O and HNO{sub 3} redistribution are investigated in a series of tests. The formation of solid PSC particles, especially of those consisting of nitric acid trihydrate, has been discussed extensively in recent years. Three particle formation schemes in accordance with the most widely used approaches have been identified and implemented. For the evaluation of PSC occurrence a new data set with unprecedented spatial and temporal coverage was available. A quantitative method for the comparison of simulation results and observations is developed and applied. It reveals that the relative PSC sighting frequency can be reproduced well with the PSC submodel whereas the detailed modelling of PSC events is beyond the scope of coarse global scale models. In addition to the development and evaluation of new PSC submodel components, parts of existing simulation programs have been

  10. The Effects of Fracture Anisotropy on the Damage Pattern and Seismic Radiation from a Chemical Explosion in a Granite Quarry

    Science.gov (United States)

    Rogers-Martinez, M. A.; Sammis, C. G.; Ezzedine, S. M.

    2017-12-01

    As part of the New England Damage Experiment (NEDE) a 122.7 kg Heavy ANFO charge was detonated at a depth of 13 m in a granite quarry in Barre Vt. Subsequent drill cores from the source region revealed that most of the resultant fracturing was concentrated in the rift plane of the highly anisotropic Barre granite. We simulated this explosion using a dynamic damage mechanics model embedded in the ABAQUS 3D finite element code. The damage mechanics was made anisotropic by taking the critical stress intensity factor to be a function of azimuth in concert with the physics of interacting parallel fractures and laboratory studies of anisotropic granite. In order to identify the effects of anisotropy, the explosion was also simulated assuming 1) no initial damage (pure elasticity) and 2) isotropic initial damage. For the anisotropic case, the calculated fracture pattern simulated that observed in NEDE. The simulated seismic radiation looked very much like that from a tensile fracture oriented in the rift plane, and similar to the crack-like moment tensor observed in the far field of many nuclear explosions.

  11. Spot test kit for explosives detection

    Science.gov (United States)

    Pagoria, Philip F; Whipple, Richard E; Nunes, Peter J; Eckels, Joel Del; Reynolds, John G; Miles, Robin R; Chiarappa-Zucca, Marina L

    2014-03-11

    An explosion tester system comprising a body, a lateral flow membrane swab unit adapted to be removeably connected to the body, a first explosives detecting reagent, a first reagent holder and dispenser operatively connected to the body, the first reagent holder and dispenser containing the first explosives detecting reagent and positioned to deliver the first explosives detecting reagent to the lateral flow membrane swab unit when the lateral flow membrane swab unit is connected to the body, a second explosives detecting reagent, and a second reagent holder and dispenser operatively connected to the body, the second reagent holder and dispenser containing the second explosives detecting reagent and positioned to deliver the second explosives detecting reagent to the lateral flow membrane swab unit when the lateral flow membrane swab unit is connected to the body.

  12. High-nitrogen explosives

    Energy Technology Data Exchange (ETDEWEB)

    Naud, D. (Darren); Hiskey, M. A. (Michael A.); Kramer, J. F. (John F.); Bishop, R. L. (Robert L.); Harry, H. H. (Herbert H.); Son, S. F. (Steven F.); Sullivan, G. K. (Gregg K.)

    2002-01-01

    The syntheses and characterization of various tetrazine and furazan compounds offer a different approach to explosives development. Traditional explosives - such as TNT or RDX - rely on the oxidation of the carbon and hydrogen atoms by the oxygen carrying nitro group to produce the explosive energy. High-nitrogen compounds rely instead on large positive heats of formation for that energy. Some of these high-nitrogen compounds have been shown to be less sensitive to initiation (e.g. by impact) when compared to traditional nitro-containing explosives of similar performances. Using the precursor, 3,6-bis-(3,5-dimethylpyrazol-1-yl)-s-tetrazine (BDT), several useful energetic compounds based on the s-tetrazine system have been synthesized and studied. The compound, 3,3{prime}-azobis(6-amino-s-tetrazine) or DAAT, detonates as a half inch rate stick despite having no oxygen in the molecule. Using perfluoroacetic acid, DAAT can be oxidized to give mixtures of N-oxide isomers (DAAT03.5) with an average oxygen content of about 3.5. This energetic mixture burns at extremely high rates and with low dependency on pressure. Another tetrazine compound of interest is 3,6-diguanidino-s-tetrazine(DGT) and its dinitrate and diperchlorate salts. DGT is easily synthesized by reacting BDT with guanidine in methanol. Using Caro's acid, DGT can be further oxidized to give 3,6-diguanidino-s-tetrazine-1,4-di-N-oxide (DGT-DO). Like DGT, the di-N-oxide can react with nitric acid or perchloric acid to give the dinitrate and the diperchlorate salts. The compounds, 4,4{prime}-diamino-3,3{prime}-azoxyfurazan (DAAF) and 4,4{prime}-diamino-3,3{prime}-azofurazan (DAAzF), may have important future roles in insensitive explosive applications. Neither DAAF nor DAAzF can be initiated by laboratory impact drop tests, yet both have in some aspects better explosive performances than 1,3,5-triamino-2,4,6-trinitrobenzene TATB - the standard of insensitive high explosives. The thermal stability of DAAz

  13. Nuclear explosives and hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, P

    1971-10-01

    A nuclear explosive 12 in. in diam and producing very little tritium is feasible in France. Such a device would be well adapted for contained nuclear explosions set off for the purpose of hydrocarbon storage or stimulation. The different aspects of setting off the explosive are reviewed. In the particular case of gas storage in a nuclear cavity in granite, it is demonstrated that the dose of irradiation received is extremely small. (18 refs.)

  14. An integral model of plume rise from high explosive detonations

    International Nuclear Information System (INIS)

    Boughton, B.A.; De Laurentis, J.M.

    1987-01-01

    A numerical model has been developed which provides a complete description of the time evolution of both the physical and thermodynamic properties of the cloud formed when a high explosive is detonated. This simulation employs the integral technique. The model equations are derived by integrating the three-dimensional conservation equations of mass, momentum and energy over the plume cross section. Assumptions are made regarding (a) plume symmetry; (b) the shape of profiles of velocity, temperature, etc. across the plume; and (c) the methodology for simulating entrainment and the effects of the crossflow induced pressure drag force on the plume. With these assumptions, the integral equations can be reduced to a set of ordinary differential equations on the plume centerline variables. Only the macroscopic plume characteristics, e.g., plume radius, centerline height, temperature and density, are predicted; details of the plume intrastructure are ignored. The model explicitly takes into account existing meteorology and has been expanded to consider the alterations in plume behavior which occur when aqueous foam is used as a dispersal mitigating material. The simulation was tested by comparison with field measurements of cloud top height and diameter. Predictions were within 25% of field observations over a wide range of explosive yield and atmospheric stability

  15. Describing the direct and indirect radiative effects of atmospheric aerosols over Europe by using coupled meteorology-chemistry simulations: a contribution from the AQMEII-Phase II exercise

    Science.gov (United States)

    Jimenez-Guerrero, Pedro; Balzarini, Alessandra; Baró, Rocío; Curci, Gabriele; Forkel, Renate; Hirtl, Marcus; Honzak, Luka; Langer, Matthias; Pérez, Juan L.; Pirovano, Guido; San José, Roberto; Tuccella, Paolo; Werhahn, Johannes; Zabkar, Rahela

    2014-05-01

    The study of the response of the aerosol levels in the atmosphere to a changing climate and how this affects the radiative budget of the Earth (direct, semi-direct and indirect effects) is an essential topic to build confidence on climate science, since these feedbacks involve the largest uncertainties nowadays. Air quality-climate interactions (AQCI) are, therefore, a key, but uncertain contributor to the anthropogenic forcing that remains poorly understood. To build confidence in the AQCI studies, regional-scale integrated meteorology-atmospheric chemistry models (i.e., models with on-line chemistry) that include detailed treatment of aerosol life cycle and aerosol impacts on radiation (direct effects) and clouds (indirect effects) are in demand. In this context, the main objective of this contribution is the study and definition of the uncertainties in the climate-chemistry-aerosol-cloud-radiation system associated to the direct radiative forcing and the indirect effect caused by aerosols over Europe, using an ensemble of fully-coupled meteorology-chemistry model simulations with the WRF-Chem model run under the umbrella of AQMEII-Phase 2 international initiative. Simulations were performed for Europe for the entire year 2010. According to the common simulation strategy, the year was simulated as a sequence of 2-day time slices. For better comparability, the seven groups applied the same grid spacing of 23 km and shared common processing of initial and boundary conditions as well as anthropogenic and fire emissions. With exception of a simulation with different cloud microphysics, identical physics options were chosen while the chemistry options were varied. Two model set-ups will be considered here: one sub-ensemble of simulations not taking into account any aerosol feedbacks (the baseline case) and another sub-ensemble of simulations which differs from the former by the inclusion of aerosol-radiation feedback. The existing differences for meteorological

  16. Multi-scale multi-physics computational chemistry simulation based on ultra-accelerated quantum chemical molecular dynamics method for structural materials in boiling water reactor

    International Nuclear Information System (INIS)

    Miyamoto, Akira; Sato, Etsuko; Sato, Ryo; Inaba, Kenji; Hatakeyama, Nozomu

    2014-01-01

    In collaboration with experimental experts we have reported in the present conference (Hatakeyama, N. et al., “Experiment-integrated multi-scale, multi-physics computational chemistry simulation applied to corrosion behaviour of BWR structural materials”) the results of multi-scale multi-physics computational chemistry simulations applied to the corrosion behaviour of BWR structural materials. In macro-scale, a macroscopic simulator of anode polarization curve was developed to solve the spatially one-dimensional electrochemical equations on the material surface in continuum level in order to understand the corrosion behaviour of typical BWR structural material, SUS304. The experimental anode polarization behaviours of each pure metal were reproduced by fitting all the rates of electrochemical reactions and then the anode polarization curve of SUS304 was calculated by using the same parameters and found to reproduce the experimental behaviour successfully. In meso-scale, a kinetic Monte Carlo (KMC) simulator was applied to an actual-time simulation of the morphological corrosion behaviour under the influence of an applied voltage. In micro-scale, an ultra-accelerated quantum chemical molecular dynamics (UA-QCMD) code was applied to various metallic oxide surfaces of Fe 2 O 3 , Fe 3 O 4 , Cr 2 O 3 modelled as same as water molecules and dissolved metallic ions on the surfaces, then the dissolution and segregation behaviours were successfully simulated dynamically by using UA-QCMD. In this paper we describe details of the multi-scale, multi-physics computational chemistry method especially the UA-QCMD method. This method is approximately 10,000,000 times faster than conventional first-principles molecular dynamics methods based on density-functional theory (DFT), and the accuracy was also validated for various metals and metal oxides compared with DFT results. To assure multi-scale multi-physics computational chemistry simulation based on the UA-QCMD method for

  17. 30 CFR 77.1301 - Explosives; magazines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Explosives; magazines. 77.1301 Section 77.1301... and Blasting § 77.1301 Explosives; magazines. (a) Detonators and explosives other than blasting agents shall be stored in magazines. (b) Detonators shall not be stored in the same magazine with explosives...

  18. A single cell model for pretreatment of wood by microwave explosion

    Science.gov (United States)

    Xianjun Li; Yongdong Zhou; Yonglin Yan; Zhiyong Cai; Fu Feng

    2010-01-01

    A theoretical model was developed to better understand the process of microwave explosion treatment of wood cells. The cell expansion and critical conditions concerning pressure and temperature of ray parenchyma cells in Eucalyptus urophylla were simulated during microwave pretreatment. The results indicate that longitudinal and circumferential stresses were generated...

  19. Material effect in the fuel-coolant interaction: structural characterization of the steam explosion debris and solidification mechanism

    International Nuclear Information System (INIS)

    Tyrpekl, V.

    2012-01-01

    This work has been performed under joint supervision between Charles University in Prague (Czech Republic) and Strasbourg University (France). It also profited from the background and cooperation of Institute of Inorganic Chemistry Academy of Science of the Czech Republic and French Commission for Atomic and Alternative energies (CEA Cadarache). Results of the work contribute to the OECD/NEA project Serena 2 (Program on Steam Explosion Resolution for Nuclear Applications). Presented thesis can be classed in the scientific field of nuclear safety and material science. It is aimed on the so-called 'molten nuclear Fuel - Coolant Interaction' (FCI) that belongs among the recent issues of the nuclear reactor severe accident R and D. During the nuclear reactor melt down accident the melted reactor load can interact with the coolant (light water). This interaction can be located inside the vessel or outside in the case of vessel break-up. These two scenarios are commonly called in- and ex-vessel FCI and they differ in the conditions such as initial pressure of the system, water sub-cooling etc. The Molten fuel - coolant interaction can progress into thermal detonation called 'steam explosion' that can challenge the reactor or containment integrity. Recent experiments have shown that the melt composition has a major effect on the occurrence and yield of such explosion. In particular, different behaviors have been observed between simulant material (alumina), which has important explosion efficiency, and some prototypic corium compositions (80 w. % UO 2 , 20% w. % ZrO 2 . This 'material effect' has launched a new interest in the post-test analyses of FCI debris in order to estimate the processes occurring during these extremely rapid phenomena. The thesis is organized in nine chapters. The chapter 1 gives the general introduction and context of the nuclear reactor accident. Major nuclear accidents (Three Miles Island 1979, Chernobyl 1986 and Fukushima 2011) are briefly

  20. Explosion metal welding

    International Nuclear Information System (INIS)

    Popoff, A.A.

    1976-01-01

    Process parameters pertaining to welding similar and dissimilar metals using explosives are reviewed. The discussion centers on the interrelationship of physical parameters which play a part in achieving desirable metallurgical results. Present activities in explosion metal welding at LASL are presented and shown how they related to the interests of the ERDA community

  1. Sensitivity to friction for primary explosives.

    Science.gov (United States)

    Matyáš, Robert; Šelešovský, Jakub; Musil, Tomáš

    2012-04-30

    The sensitivity to friction for a selection of primary explosives has been studied using a small BAM friction apparatus. The probit analysis was used for the construction of a sensitivity curve for each primary explosive tested. Two groups of primary explosives were chosen for measurement (a) the most commonly used industrially produced primary explosives (e.g. lead azide, tetrazene, dinol, lead styphnate) and (b) the most produced improvised primary explosives (e.g. triacetone triperoxide, hexamethylenetriperoxide diamine, mercury fulminate, acetylides of heavy metals). A knowledge of friction sensitivity is very important for determining manipulation safety for primary explosives. All the primary explosives tested were carefully characterised (synthesis procedure, shape and size of crystals). The sensitivity curves obtained represent a unique set of data, which cannot be found anywhere else in the available literature. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Zirconium hydride containing explosive composition

    Science.gov (United States)

    Walker, Franklin E.; Wasley, Richard J.

    1981-01-01

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

  3. Close-in airblast from underground explosions

    Energy Technology Data Exchange (ETDEWEB)

    Vortman, L J [Sandia Laboratories, Albuquerque, NM (United States)

    1970-05-15

    Air overpressures as a function of time have been measured from surface zero to about 170 ft/lb{sup 1/3} along the ground from nuclear and chemical explosions. Charge depths varied from the surface to depths below which explosion gases are contained. A ground-shock-induced air pressure pulse is clearly distinguishable from the pulse caused by venting gases. Measured peak overpressures show reasonable agreement with the theoretical treatment by Monta. In a given medium the suppression of blast with explosion burial depth is a function of the relative distance at which the blast is observed. Rates of suppression of peak overpressure with charge burial are different for the two pulses. Rates are determined for each pulse over the range of distances at which measurements have been made of air overpressure from chemical explosions in several media. Nuclear data are available from too few shots for similar dependence on burial depth and distance to be developed, but it is clear that the gas venting peak overpressure from nuclear explosions is much more dependent on medium than that from chemical explosions. For above-ground explosions, experiment has shown that airblast from a I-kiloton nuclear explosion is equal to that from a 0.5-kiloton TNT explosion. Data on ground-shock-induced airblast is now sufficient to show that a similar relationship may exist for buried explosions. Because of medium dependence of the gas venting pulse from nuclear explosions, data from additional nuclear events will be required before a chemical/nuclear airblast equivalence can be determined for the gas-venting pulse. (author)

  4. 8. Peaceful uses of nuclear explosions

    International Nuclear Information System (INIS)

    Musilek, L.

    1992-01-01

    The chapter deals with peaceful uses of nuclear explosions. Described are the development of the underground nuclear explosion, properties of radionuclides formed during the explosion, their distribution, the release of radioactive products of underground nuclear explosions into the air, their propagation in the atmosphere, and fallout in the landscape. (Z.S.). 1 tab., 8 figs., 19 refs

  5. Ultra Wide X-Band Microwave Imaging of Concealed Weapons and Explosives Using 3D-SAR Technique

    Directory of Open Access Journals (Sweden)

    P. Millot

    2015-01-01

    Full Text Available In order to detect and image concealed weapons and explosives, an electromagnetic imaging tool with its related signal processing is presented. The aim is to penetrate clothes and to find personal-born weapons and explosives under clothes. The chosen UWB frequency range covers the whole X-band. The frequency range is justified after transmission measurements of numerous clothes that are dry or slightly wet. The apparatus and the 3D near-field SAR processor are described. A strategy for contour identification is presented with results of some simulants of weapon and explosive. A conclusion is drawn on the possible future of this technique.

  6. An approach to incorporate the detonation shock dynamics into the calculation of explosive acceleration of metals

    International Nuclear Information System (INIS)

    Li Qingzhong; Sun Chengwei; Zhao Feng; Gao Wen; Wen Shanggang; Liu Wenhan

    1999-11-01

    The generalized geometrical optics model for the detonation shock dynamics (DSD) has been incorporated into the two dimensional hydro-code WSU to form a combination code ADW for numerical simulation of explosive acceleration of metals. An analytical treatment of the coupling conditions at the nodes just behind the detonation front is proposed. The experiments on two kinds of explosive-flyer assemblies with different length/diameter ratio were carried out to verify the ADW calculations, where the tested explosive was HMX or TATB based. It is found that the combination of DSD and hydro-code can improve the calculation precision, and has advantages in larger meshes and less CPU time

  7. Steam explosion studies with single drops of molten refractory materials

    International Nuclear Information System (INIS)

    Nelson, L.S.

    1980-01-01

    Laser heating, levitation melting, and metal combustion were used to prepare individual drops of molten refractory materials which simulate LWR fuel melt products. Drop temperatures ranged from approx. = 1500 to > 3000K. These drops, several millimeters in diameter, were injected into water and subjected to pressure transients (approx. = 1MPa peak pressures) generated by a submerged exploding bridgewire. Molten oxides of Fe, Al and Zr could be induced to explode with bridgewire initiation. High speed films showed the explosions with exceptional clarity, and pressure transducer records could be correlated with individual frames in the films. Pressure spikes one or two MPa high were generated whenever an explosion occurred. Debris particles were mostly spheroidal, with diameters in the range 10 to 1000 μm

  8. Three Dimensional Analysis of Induced Detonation of Cased Explosive

    Science.gov (United States)

    2014-10-16

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

  9. 27 CFR 70.445 - Commerce in explosives.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 2 2010-04-01 2010-04-01 false Commerce in explosives. 70... Cartridges, and Explosives § 70.445 Commerce in explosives. Part 55 of title 27 CFR contains the regulations..., explosives, (b) Permits for users who buy or transport explosives in interstate or foreign commerce, (c...

  10. Idaho Explosives Detection System

    International Nuclear Information System (INIS)

    Reber, Edward L.; Blackwood, Larry G.; Edwards, Andrew J.; Jewell, J. Keith; Rohde, Kenneth W.; Seabury, Edward H.; Klinger, Jeffery B.

    2005-01-01

    The Idaho Explosives Detection System was developed at the Idaho National Laboratory (INL) to respond to threats imposed by delivery trucks potentially carrying explosives into military bases. A full-scale prototype system has been built and is currently undergoing testing. The system consists of two racks, one on each side of a subject vehicle. Each rack includes a neutron generator and an array of NaI detectors. The two neutron generators are pulsed and synchronized. A laptop computer controls the entire system. The control software is easily operable by minimally trained staff. The system was developed to detect explosives in a medium size truck within a 5-min measurement time. System performance was successfully demonstrated with explosives at the INL in June 2004 and at Andrews Air Force Base in July 2004

  11. Idaho Explosives Detection System

    Energy Technology Data Exchange (ETDEWEB)

    Reber, Edward L. [Idaho National Laboratory, 2525 N. Freemont Ave., Idaho Falls, ID 83415-2114 (United States)]. E-mail: reber@inel.gov; Blackwood, Larry G. [Idaho National Laboratory, 2525 N. Freemont Ave., Idaho Falls, ID 83415-2114 (United States); Edwards, Andrew J. [Idaho National Laboratory, 2525 N. Freemont Ave., Idaho Falls, ID 83415-2114 (United States); Jewell, J. Keith [Idaho National Laboratory, 2525 N. Freemont Ave., Idaho Falls, ID 83415-2114 (United States); Rohde, Kenneth W. [Idaho National Laboratory, 2525 N. Freemont Ave., Idaho Falls, ID 83415-2114 (United States); Seabury, Edward H. [Idaho National Laboratory, 2525 N. Freemont Ave., Idaho Falls, ID 83415-2114 (United States); Klinger, Jeffery B. [Idaho National Laboratory, 2525 N. Freemont Ave., Idaho Falls, ID 83415-2114 (United States)

    2005-12-15

    The Idaho Explosives Detection System was developed at the Idaho National Laboratory (INL) to respond to threats imposed by delivery trucks potentially carrying explosives into military bases. A full-scale prototype system has been built and is currently undergoing testing. The system consists of two racks, one on each side of a subject vehicle. Each rack includes a neutron generator and an array of NaI detectors. The two neutron generators are pulsed and synchronized. A laptop computer controls the entire system. The control software is easily operable by minimally trained staff. The system was developed to detect explosives in a medium size truck within a 5-min measurement time. System performance was successfully demonstrated with explosives at the INL in June 2004 and at Andrews Air Force Base in July 2004.

  12. Numerical Simulation of Blast Action on Civil Structures in Urban Environment

    Science.gov (United States)

    Valger, Svetlana A.; Fedorova, Natalya N.; Fedorov, Alexander V.

    2017-10-01

    Nowadays, a lot of industrial accidents accompanied by explosions are happening throughout the world. Also, increase in the number of terrorist acts committed by means of explosions is observed. For improving safety of buildings and structures it is necessary to raise their resistance to explosive effects, as well as to be able to predict degree of potential damage upon explosive loads of various intensities. One of the principal goals in designing the structure resistant to explosive effects is to determine the dynamic response of structures to the impact of the blast wave. To this end, the transient pressure loads on the walls of the civil engineering structures are to be determined. The simulation of explosion is highly complicated, involving an explosion causing the shock wave propagation in air and then interaction with a structure. The engineering-level techniques permit one to estimate an explosive shock impact only for isolated buildings. The complexity of the building, the presence of nearby structures and the surrounding environment cannot be taken into account. Advanced computer aid engineering (CAE) software techniques combined with the latest methods of discrete three-dimensional city modelling permits one to simulate and analyse the effects of explosions in urban areas with a precision which previously was not possible. In the paper, the simulation results are presented of shock wave forming due to a spherical explosive charge and its propagation in the vicinity of geometrical configuration imitating an urban environment. The numerical simulation of a flow in the vicinity of prisms of different cross-sections and heights located on a flat plate was performed. The calculations are carried out in a three-dimensional non-viscous formulation using ANSYS software. On a basis of simulation results, a complex wave structures were analysed, and all the peculiarities of flows and pressure history records on building walls were described and explained. The

  13. Trace explosives sensor testbed (TESTbed)

    Science.gov (United States)

    Collins, Greg E.; Malito, Michael P.; Tamanaha, Cy R.; Hammond, Mark H.; Giordano, Braden C.; Lubrano, Adam L.; Field, Christopher R.; Rogers, Duane A.; Jeffries, Russell A.; Colton, Richard J.; Rose-Pehrsson, Susan L.

    2017-03-01

    A novel vapor delivery testbed, referred to as the Trace Explosives Sensor Testbed, or TESTbed, is demonstrated that is amenable to both high- and low-volatility explosives vapors including nitromethane, nitroglycerine, ethylene glycol dinitrate, triacetone triperoxide, 2,4,6-trinitrotoluene, pentaerythritol tetranitrate, and hexahydro-1,3,5-trinitro-1,3,5-triazine. The TESTbed incorporates a six-port dual-line manifold system allowing for rapid actuation between a dedicated clean air source and a trace explosives vapor source. Explosives and explosives-related vapors can be sourced through a number of means including gas cylinders, permeation tube ovens, dynamic headspace chambers, and a Pneumatically Modulated Liquid Delivery System coupled to a perfluoroalkoxy total-consumption microflow nebulizer. Key features of the TESTbed include continuous and pulseless control of trace vapor concentrations with wide dynamic range of concentration generation, six sampling ports with reproducible vapor profile outputs, limited low-volatility explosives adsorption to the manifold surface, temperature and humidity control of the vapor stream, and a graphical user interface for system operation and testing protocol implementation.

  14. Analysis of the Explosive Internal Impact on the Barriers of Building Structures

    Science.gov (United States)

    Siwiński, Jarosław; Stolarski, Adam

    2017-10-01

    Work issues concern the safety of construction in relation to the hazards arising from explosion of the explosive charge located inside the building. The algorithms proposed in the paper for determining the parameters of the overpressure wave resulting from the detonation of clustered explosive charges, determine the basis for numerical simulation analyzes. Determination of the maximum value of peak pressure on the wave forehead of an internal explosion is presented on the basis of reflected wave analysis. Changeability in time of the internal explosion action describes the overpressure phase only. The analysis of the load caused by the internal explosive charge detonation was carried out under conditions of the undisturbed standard atmosphere. A load determination algorithm has been developed, taking into account the geometrical characteristics of the building barriers and the rooms as well as the parameters of environment in which the detonation occurs. The way of taking into account the influence of venting surfaces, i.e. windows, doors, ventilation ducts, on the overpressure wave parameters, was presented. Discloses a method to take into account the effect of the surface relief, i.e. windows, doors, air ducts, pressure wave parameters. Modification of the method for explosive overpressure determination presented by Cormie, Smith, Mays (2009), was proposed in the paper. This modification was developed on the basis of substitute impulse analysis for multiple overpressure pulses. In order to take into account the pressure distribution of explosive gases on the barrier surface, the method of modification the relationship for determination the changeability over time and space of the pressure of explosive gases, was presented. For this purpose, the changeability of the pressure wave angles of incidence to the barrier and the distance of the explosive charge to any point on the surface of the barrier, was taken into account. Based on the developed procedure, the

  15. Explosive magnetic reconnection caused by an X-shaped current-vortex layer in a collisionless plasma

    Energy Technology Data Exchange (ETDEWEB)

    Hirota, M.; Hattori, Y. [Institute of Fluid Science, Tohoku University, Sendai, Miyagi 980-8677 (Japan); Morrison, P. J. [Department of Physics and Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States)

    2015-05-15

    A mechanism for explosive magnetic reconnection is investigated by analyzing the nonlinear evolution of a collisionless tearing mode in a two-fluid model that includes the effects of electron inertia and temperature. These effects cooperatively enable a fast reconnection by forming an X-shaped current-vortex layer centered at the reconnection point. A high-resolution simulation of this model for an unprecedentedly small electron skin depth d{sub e} and ion-sound gyroradius ρ{sub s}, satisfying d{sub e}=ρ{sub s}, shows an explosive tendency for nonlinear growth of the tearing mode, where it is newly found that the explosive widening of the X-shaped layer occurs locally around the reconnection point with the length of the X shape being shorter than the domain length and the wavelength of the linear tearing mode. The reason for the onset of this locally enhanced reconnection is explained theoretically by developing a novel nonlinear and nonequilibrium inner solution that models the local X-shaped layer, and then matching it to an outer solution that is approximated by a linear tearing eigenmode with a shorter wavelength than the domain length. This theoretical model proves that the local reconnection can release the magnetic energy more efficiently than the global one and the estimated scaling of the explosive growth rate agrees well with the simulation results.

  16. Applications of Monte Carlo technique in the detection of explosives, narcotics and fissile material using neutron sources

    International Nuclear Information System (INIS)

    Sinha, Amar; Kashyap, Yogesh; Roy, Tushar; Agrawal, Ashish; Sarkar, P.S.; Shukla, Mayank

    2009-01-01

    The problem of illicit trafficking of explosives, narcotics or fissile materials represents a real challenge to civil security. Neutron based detection systems are being actively explored worldwide as a confirmatory tool for applications in the detection of explosives either hidden inside a vehicle or a cargo container or buried inside soil. The development of a system and its experimental testing is a tedious process and to develop such a system each experimental condition needs to be theoretically simulated. Monte Carlo based methods are used to find an optimized design for such detection system. In order to design such systems, it is necessary to optimize source and detector system for each specific application. The present paper deals with such optimization studies using Monte Carlo technique for tagged neutron based system for explosives and narcotics detection hidden in a cargo and landmine detection using backscatter neutrons. We will also discuss some simulation studies on detection of fissile material and photo-neutron source design for applications on cargo scanning. (author)

  17. Simulation of radionuclide chemistry and sorption characteristics in the geosphere by artificial intelligence technique

    International Nuclear Information System (INIS)

    Liu Shangjyh; National Tsing Hua Univ., Hsinchu; Wang Shigang; Ho Liwei

    1988-01-01

    An expert system operated in a personal computer is employed to simulate chemistry and sorption phenomena of radionuclides in the geosphere. The system handles both qualitative and quantitative analyses primarily for the actinides and fission products. The system also incorporates data bases of several groundwater and rock types with mineral and chemical compositions, the distribution coefficients of nuclides for minerals, etc. The decision rule base facilitates this system to carry out the reasoning procedures to predict the solubility-limiting phase, solute species, oxidation states and possible complex formations of radionuclides, as well as to calculate the distribution coefficients and retardation factors in a geological formation, provided that the essential groundwater and host rock information are available. It is concluded that this device of artificial intelligence provides a vehicle to accumulate developed human knowledge and serves as a tool not only for simulating the complicated radionuclide behaviour in the geosphere, but also for instructional or educational purpose in this field. (orig.)

  18. Report on the treatability study for inerting small quantities of radioactive explosives and explosive components

    International Nuclear Information System (INIS)

    Loyola, V.M.; Reber, S.D.

    1996-02-01

    As a result of Sandia's radiation hardening testing on a variety of its explosive components, radioactive waste streams were generated and have to be disposed of as radioactive waste. Due to the combined hazards of explosives and radioactivity, Sandia's Radioactive and Mixed Waste Management organization did not have a mechanism for disposal of these waste streams. This report documents the study done to provide a method for the removal of the explosive hazard from those waste streams. The report includes the design of the equipment used, procedures followed, results from waste stream analog tests and the results from the actual explosive inerting tests on radioactive samples. As a result of the inerting treatment, the waste streams were rendered non-explosive and, thus, manageable through normal radioactive waste disposal channels

  19. The Study on the Quantitative Analysis in LPG Tank's Fire and Explosion

    Energy Technology Data Exchange (ETDEWEB)

    Bae, S.J.; Kim, B.J. [Department of chemical Engineering, Soongsil University, Seoul (Korea)

    1999-04-01

    Chemical plant's fire and explosion does not only damage to the chemical plants themselves but also damage to people in or near of the accident spot and the neighborhood of chemical plant. For that reason, Chemical process safety management has become important. One of safety management methods is called 'the quantitative analysis', which is used to reduce and prevent the accident. The results of the quantitative analysis could be used to arrange the equipments, evaluate the minimum safety distance, prepare the safety equipments. In this study we make the computer program to make easy to do quantitative analysis of the accident. The output of the computer program is the magnitude of fire(pool fire and fireball) and explosion (UVCE and BLEVE) effects. We used the thermal radiation as a measure of fire magnitude and used the overpressure as a measure of explosion magnitude. In case of BLEVE, the fly distance of fragment can be evaluated. Also probit analysis was done in every case. As the case study, Buchun LPG explosion accident in Korea was analysed by the program developed. The simulation results showed that the permissible distance was 800m and probit analysis showed that 1st degree burn, 2nd degree burn, and death distances are 450, 280, 260m, respectively. the simulation results showed the good agreement with the result from SAFER PROGRAM made by DuPont. 13 refs., 4 figs., 2 tabs.

  20. Study of film boiling collapse behavior during vapor explosion

    International Nuclear Information System (INIS)

    Yagi, Masahiro; Yamano, Norihiro; Sugimoto, Jun; Abe, Yutaka; Adachi, Hiromichi; Kobayashi, Tomoyoshi.

    1996-06-01

    Possible large scale vapor explosions are safety concern in nuclear power plants during severe accident. In order to identify the occurrence of the vapor explosion and to estimate the magnitude of the induced pressure pulse, it is necessary to investigate the triggering condition for the vapor explosion. As a first step of this study, scooping analysis was conducted with a simulation code based on thermal detonation model. It was found that the pressure at the collapse of film boiling much affects the trigger condition of vapor explosion. Based on this analytical results, basic experiments were conducted to clarify the collapse conditions of film boiling on a high temperature solid ball surface. Film boiling condition was established by flooding water onto a high temperature stainless steel ball heated by a high frequency induction heater. After the film boiling was established, the pressure pulse generated by a shock tube was applied to collapse the steam film on the ball surface. As the experimental boundary conditions, materials and size of the balls, magnitude of pressure pulse and initial temperature of the carbon and stainless steel balls were varied. The transients of pressure and surface temperature were measured. It was found that the surface temperature on the balls sharply decreased when the pressure wave passed through the film on balls. Based on the surface temperature behavior, the film boiling collapse pattern was found to be categorized into several types. Especially, the pattern for stainless steel ball was categorized into three types; no collapse, collapse and reestablishment after collapse. It was thus clarified that the film boiling collapse behavior was identified by initial conditions and that the pressure required to collapse film boiling strongly depended on the initial surface temperature. The present results will provide a useful information for the analysis of vapor explosions based on the thermal detonation model. (J.P.N.)

  1. Large eddy simulation of reactive pollutants in a deep urban street canyon: Coupling dynamics with O3-NOx-VOC chemistry.

    Science.gov (United States)

    Zhong, Jian; Cai, Xiao-Ming; Bloss, William James

    2017-05-01

    A large eddy simulation (LES) model coupled with O 3 -NO x -VOC chemistry is implemented to simulate the coupled effects of emissions, mixing and chemical pre-processing within an idealised deep (aspect ratio = 2) urban street canyon under a weak wind condition. Reactive pollutants exhibit significant spatial variations in the presence of two vertically aligned unsteady vortices formed in the canyon. Comparison of the LES results from two chemical schemes (simple NO x -O 3 chemistry and a more comprehensive Reduced Chemical Scheme (RCS) chemical mechanism) shows that the concentrations of NO 2 and O x inside the street canyon are enhanced by approximately 30-40% via OH/HO 2 chemistry. NO, NO x , O 3 , OH and HO 2 are chemically consumed, while NO 2 and O x (total oxidant) are chemically produced within the canyon environment. Within-canyon pre-processing increases oxidant fluxes from the canyon to the overlying boundary layer, and this effect is greater for deeper street canyons (as found in many traditional European urban centres) than shallower (lower aspect ratio) streets. There is clear evidence of distinct behaviours for emitted chemical species and entrained chemical species, and positive (or negative) values of intensities of segregations are found between pairs of species with similar (or opposite) behaviour. The simplified two-box model underestimated NO and O 3 levels, but overestimated NO 2 levels for both the lower and upper canyon compared with the more realistic LES-chemistry model. This suggests that the segregation effect due to incomplete mixing reduces the chemical conversion rate of NO to NO 2 . This study reveals the impacts of nonlinear O 3 -NO x -VOC photochemical processes in the incomplete mixing environment and provides a better understanding of the pre-processing of emissions within canyons, prior to their release to the urban boundary layer, through the coupling of street canyon dynamics and chemistry. Copyright © 2017 Elsevier Ltd

  2. Lightning vulnerability of nuclear explosive test systems at the Nevada Test Site

    International Nuclear Information System (INIS)

    Hasbrouck, R.T.

    1985-01-01

    A task force chartered to evaluate the effects of lightning on nuclear explosives at the Nevada Test Site has made several recommendations intended to provide lightning-invulnerable test device systems. When these recommendations have been implemented, the systems will be tested using full-threat-level simulated lightning

  3. R-22 vapor explosions

    International Nuclear Information System (INIS)

    Anderson, R.P.; Armstrong, D.R.

    1977-01-01

    Previous experimental and theoretical studies of R-22 vapor explosions are reviewed. Results from two experimental investigations of vapor explosions in a medium scale R-22/water system are reported. Measurements following the drop of an unrestrained mass of R-22 into a water tank demonstrated the existence of two types of interaction behavior. Release of a constrained mass of R-22 beneath the surface of a water tank improved the visual resolution of the system thus allowing identification of two interaction mechansims: at low water temperatures, R-22/water contact would produce immediate violent boiling; at high water temperatures a vapor film formed around its R-22 as it was released, explosions were generated by a surface wave which initiated at a single location and propagated along the vapor film as a shock wave. A new vapor explosion model is proposed, it suggests explosions are the result of a sequence of three independent steps: an initial mixing phase, a trigger and growth phase, and a mature phase where a propagating shock wave accelerates the two liquids into a collapsing vapor layer causing a high velocity impact which finely fragments and intermixes the two liquids

  4. Eighteenth annual West Coast theoretical chemistry conference

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-05-01

    Abstracts are presented from the eighteenth annual west coast theoretical chemistry conference. Topics include molecular simulations; quasiclassical simulations of reactions; photodissociation reactions; molecular dynamics;interface studies; electronic structure; and semiclassical methods of reactive systems.

  5. Performance evaluation of granular activated carbon system at Pantex: Rapid small-scale column tests to simulate removal of high explosives from contaminated groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Henke, J.L.; Speitel, G.E. [Univ. of Texas, Austin, TX (United States). Dept. of Civil Engineering

    1998-08-01

    A granular activated carbon (GAC) system is now in operation at Pantex to treat groundwater from the perched aquifer that is contaminated with high explosives. The main chemicals of concern are RDX and HMX. The system consists of two GAC columns in series. Each column is charged with 10,000 pounds of Northwestern LB-830 GAC. At the design flow rate of 325 gpm, the hydraulic loading is 6.47 gpm/ft{sup 2}, and the empty bed contact time is 8.2 minutes per column. Currently, the system is operating at less than 10% of its design flow rate, although flow rate increases are expected in the relatively near future. This study had several objectives: Estimate the service life of the GAC now in use at Pantex; Screen several GACs to provide a recommendation on the best GAC for use at Pantex when the current GAC is exhausted and is replaced; Determine the extent to which natural organic matter in the Pantex groundwater fouls GAC adsorption sites, thereby decreasing the adsorption capacity for high explosives; and Determine if computer simulation models could match the experimental results, thereby providing another tool to follow system performance.

  6. Performance evaluation of granular activated carbon system at Pantex: Rapid small-scale column tests to simulate removal of high explosives from contaminated groundwater

    International Nuclear Information System (INIS)

    Henke, J.L.; Speitel, G.E.

    1998-08-01

    A granular activated carbon (GAC) system is now in operation at Pantex to treat groundwater from the perched aquifer that is contaminated with high explosives. The main chemicals of concern are RDX and HMX. The system consists of two GAC columns in series. Each column is charged with 10,000 pounds of Northwestern LB-830 GAC. At the design flow rate of 325 gpm, the hydraulic loading is 6.47 gpm/ft 2 , and the empty bed contact time is 8.2 minutes per column. Currently, the system is operating at less than 10% of its design flow rate, although flow rate increases are expected in the relatively near future. This study had several objectives: Estimate the service life of the GAC now in use at Pantex; Screen several GACs to provide a recommendation on the best GAC for use at Pantex when the current GAC is exhausted and is replaced; Determine the extent to which natural organic matter in the Pantex groundwater fouls GAC adsorption sites, thereby decreasing the adsorption capacity for high explosives; and Determine if computer simulation models could match the experimental results, thereby providing another tool to follow system performance

  7. Parametric Explosion Spectral Model

    Energy Technology Data Exchange (ETDEWEB)

    Ford, S R; Walter, W R

    2012-01-19

    Small underground nuclear explosions need to be confidently detected, identified, and characterized in regions of the world where they have never before occurred. We develop a parametric model of the nuclear explosion seismic source spectrum derived from regional phases that is compatible with earthquake-based geometrical spreading and attenuation. Earthquake spectra are fit with a generalized version of the Brune spectrum, which is a three-parameter model that describes the long-period level, corner-frequency, and spectral slope at high-frequencies. Explosion spectra can be fit with similar spectral models whose parameters are then correlated with near-source geology and containment conditions. We observe a correlation of high gas-porosity (low-strength) with increased spectral slope. The relationship between the parametric equations and the geologic and containment conditions will assist in our physical understanding of the nuclear explosion source.

  8. Expediency of application of explosion-relief constructions to ensure explosion resistance of production buildings

    Directory of Open Access Journals (Sweden)

    Lyapin Anton

    2016-01-01

    Full Text Available The article presents a model of economic evaluation and selection of explosion-relief constructions (ERC, as well as determination of explosion protection efficiency of buildings and structures provided on a stage of construction. It has been shown that definition of economic efficiency of ERС is the evaluation of its application for buildings with remote or automatically controlled production. It has been determined that an important role in design of explosive industrial facilities is played by selection of the economically feasible and effective materials for ERC. When selecting materials it is necessary to consider probability and yield of explosions. Necessity to create the methods allow considering such probability has been revealed.

  9. Violent Explosive Eruptions in the Ararat Valley, Armenia and Associated Volcanic Hazards

    Science.gov (United States)

    Meliksetian, Khachatur; Savov, Ivan; Connor, Charles; Gevorgyan, Hripsime; Connor, Laura; Navasardyan, Gevorg; Manucharyan, Davit; Jrbashyan, Ruben; Ghukasyan, Yura

    2016-04-01

    The Anatolian-Armenian-Iranian volcanically active orogenic plateau is located in the collision zone between the Arabian and Eurasian plates. The majority of regional geodynamic and petrologic models of collision-related magmatism use the model proposed by Keskin (2003), where volcanism is driven by Neo-Tethyan slab break-off, however an updated model by Neill et al. (2015) and Skolbeltsyn et al.(2014) comprise break-off of two slabs. One of the significant (and understudied) features of the regionally extensive collision zone volcanism is the diversity of eruption styles and also the presence of large number of highly explosive (Plinian) eruptions with VEI≥5 during the Middle-Upper Pleistocene. Geological records of the Ararat depression include several generations of thick low aspect ratio Quaternary ignimbrites erupted from Aragats volcano, as well as up to 3 m thick ash and pumice fall deposit from the Holocene-historically active Ararat volcano. The Ararat tephra fall deposit is studied at 12 newly discovered outcrops covering an area ˜1000 km2. It is noteworthy, that the Ararat tephra deposits are loose and unwelded and observed only in cross-sections in small depressions or in areas where they were rapidly covered by younger, colluvium deposits, presumably of Holocene age. Therefore, the spatial extent of the explosive deposits of Ararat is much bigger but not well preserved due to rapid erosion. Whole rock elemental, isotope (Sr, Nd) and mineral chemistry data demonstrate significant difference in the magma sources of the large Aragats and Ararat stratovolcanoes. Lavas and pyroclastic products of Aragats are high K calc-alkaline, and nearly always deprived from H2O rich phases such as amphibole. In contrasts lavas and pyroclastic products from Ararat are medium K calc-alkaline and volatile-rich (>4.6 wt% H2O and amphibole bearing) magmas. Here we shall attempt to reveal possible geochemical triggers of explosive eruptions in these volcanoes and assess

  10. Concept and numerical simulations of a reactive anti-fragment armour layer

    Science.gov (United States)

    Hušek, Martin; Kala, Jiří; Král, Petr; Hokeš, Filip

    2017-07-01

    The contribution describes the concept and numerical simulation of a ballistic protective layer which is able to actively resist projectiles or smaller colliding fragments flying at high speed. The principle of the layer was designed on the basis of the action/reaction system of reactive armour which is used for the protection of armoured vehicles. As the designed ballistic layer consists of steel plates simultaneously combined with explosive material - primary explosive and secondary explosive - the technique of coupling the Finite Element Method with Smoothed Particle Hydrodynamics was used for the simulations. Certain standard situations which the ballistic layer should resist were simulated. The contribution describes the principles for the successful execution of numerical simulations, their results, and an evaluation of the functionality of the ballistic layer.

  11. Explosives 92. Conference proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Farnfield, R.A. (ed.)

    1992-01-01

    17 papers are presented. Topics covered include: the POG system - a new concept in the use of ANFO; demolition of a motorway bridge; presplit and smooth blasting; VIBReX - a predictive code for assessing the effect of blast design on ground vibration; ground vibrations from blasting; digital seismographs; human response to blasting and the effects on planning conditions; landform construction by restoration blasting; use of small diameter explosives; efficient priming; safety management in the explosives industry; and the law on packaging of explosives. Two papers have been abstracted separately.

  12. Problems in the theory of point explosions

    Science.gov (United States)

    Korobeinikov, V. P.

    The book is concerned with the development of the theory of point explosions, which is relevant to the study of such phenomena as the initiation of detonation, high-power explosions, electric discharges, cosmic explosions, laser blasts, and hypersonic aerodynamics. The discussion covers the principal equations and the statement of problems; linearized non-self-similar one-dimensional problems; spherical, cylindrical, and plane explosions with allowance for counterpressure under conditions of constant initial density; explosions in a combustible mixture of gases; and point explosions in inhomogeneous media with nonsymmetric energy release. Attention is also given to point explosions in an electrically conducting gas with allowance for the effect of the magnetic field and to the propagation of perturbations from solar flares.

  13. Direct numerical simulations of non-premixed ethylene-air flames: Local flame extinction criterion

    KAUST Repository

    Lecoustre, Vivien R.

    2014-11-01

    Direct Numerical Simulations (DNS) of ethylene/air diffusion flame extinctions in decaying two-dimensional turbulence were performed. A Damköhler-number-based flame extinction criterion as provided by classical large activation energy asymptotic (AEA) theory is assessed for its validity in predicting flame extinction and compared to one based on Chemical Explosive Mode Analysis (CEMA) of the detailed chemistry. The DNS code solves compressible flow conservation equations using high order finite difference and explicit time integration schemes. The ethylene/air chemistry is simulated with a reduced mechanism that is generated based on the directed relation graph (DRG) based methods along with stiffness removal. The numerical configuration is an ethylene fuel strip embedded in ambient air and exposed to a prescribed decaying turbulent flow field. The emphasis of this study is on the several flame extinction events observed in contrived parametric simulations. A modified viscosity and changing pressure (MVCP) scheme was adopted in order to artificially manipulate the probability of flame extinction. Using MVCP, pressure was changed from the baseline case of 1 atm to 0.1 and 10 atm. In the high pressure MVCP case, the simulated flame is extinction-free, whereas in the low pressure MVCP case, the simulated flame features frequent extinction events and is close to global extinction. Results show that, despite its relative simplicity and provided that the global flame activation temperature is correctly calibrated, the AEA-based flame extinction criterion can accurately predict the simulated flame extinction events. It is also found that the AEA-based criterion provides predictions of flame extinction that are consistent with those provided by a CEMA-based criterion. This study supports the validity of a simple Damköhler-number-based criterion to predict flame extinction in engineering-level CFD models. © 2014 The Combustion Institute.

  14. Effects of explosions in hard rocks

    International Nuclear Information System (INIS)

    Heuze, F.E.; Walton, O.R.; Maddix, D.M.; Shaffer, R.J.; Butkovich, T.R.

    1993-01-01

    This work relates to explosions in hard rocks (ex: basalt, granite, limestone...). Hard rock masses typically have a blocky structure created by the existence of geologic discontinuities such as bedding contacts, faults, and joints. At very high pressure - hundreds of kilobars and above - these discontinuities do not act separately, and the rock appears to be an equivalent continuous medium. At stress of a few tens of kilobars and below, the geologic discontinuities control the kinematics of the rock masses. Hence, the simulation of rock dynamics, anywhere but in the very-near source region, should account for those kinematics

  15. Simulation of comprehensive chemistry and atmospheric methane lifetime in the LGM with EMAC

    Science.gov (United States)

    Gromov, Sergey; Steil, Benedikt

    2017-04-01

    Past records of atmospheric methane (CH4) abundance/isotope composition may provide a substantial insight on C exchanges in the Earth System (ES). When simulated in the climate models, CH4 helps to identify climate parameters transitions via triggering of its different (natural) sources, with a proviso that its sinks are adequately represented in the model. The latter are still a matter of large uncertainty in the studies focussing on the interpretation of CH4 evolution throughout Last Glacial Maximum (LGM), judging the conferred span of tropospheric CH4 lifetime (λ) of 3-16 yr [1-4]. In this study, we attempt to: (i) deliver the most adequate estimate of the LGM atmospheric sink of CH4 in the EMAC AC-GCM [5] equipped with the comprehensive representation of atmospheric chemistry [6], (ii) reveal the ES and CH4 emission parameters that are most influential for λ and (iii) based on these findings, suggest a parameterisation for λ that may be consistently used in climate models. In pursuing (i) we have tuned the EMAC model for simulating LGM atmospheric chemistry state, including careful revisiting of the trace gases emissions from the biosphere, biomass burning/lightning source, etc. The latter affect the key simulated component bound with λ, viz. the abundance and distribution of the hydroxyl radicals (OH) which, upon reacting with CH4, constitute its main tropospheric sink. Our preliminary findings suggest that OH is buffered in the atmosphere in a similar fashion to preindustrial climate, which in line with the recent studies employing comprehensive chemistry mechanisms (e.g., [3]). The analysis in (ii) suggests that tropospheric λ values may be qualitatively described as a convolution of values typical for zonal domain with high and low photolytic recycling rates (i.e. tropics and extra-tropics), as in the latter a dependence of the zonal average λ value on the CH4 emission strength exists. We further use the extensive diagnostic in EMAC to infer the

  16. Dimethylsulfide chemistry: annual, seasonal, and spatial impacts on SO_4^(2-)

    Science.gov (United States)

    We incorporated oceanic emissions and atmospheric chemistry of dimethylsulfide (DMS) into the hemispheric Community Multiscale Air Quality model and performed annual model simulations without and with DMS chemistry. The model without DMS chemistry predicts higher concentrations o...

  17. The present status of scientific applications of nuclear explosions

    International Nuclear Information System (INIS)

    Cowan, G.A.; Diven, B.C.

    1970-01-01

    This is the fourth in a series of symposia which started, in 1957 at Livermore with the purpose of examining the peaceful uses of nuclear explosives. Although principal emphasis has b een placed on technological applications, the discussions have, from the outset, included the fascinating question of scientific uses. Of the possible scientific applications which were mentioned at the 1957 meeting, the proposals which attracted most attention involved uses of nuclear explosions for research in seismology. It is interesting to note that since then a very large and stimulating body of data in the field of seismology has been collected from nuclear tests. Ideas for scientific applications of nuclear explosions go back considerably further than 1957. During the war days Otto Frisch at Los Alamos suggested that a fission bomb would provide an excellent source of fast neutrons which could be led down a vacuum pipe and used for experiments in a relatively unscattered state. This idea, reinvented, modified, and elaborated upon in the ensuing twenty-five years, provides the basis for much of the research discussed in this morning's program. In 1952 a somewhat different property of nuclear explosions, their ability to produce intense neutron exposures on internal targets and to synthesize large quantities of multiple neutron capture products, was dramatically brought to our attention by analysis of debris from the first large thermonuclear explosion (Mike) in which the elements einsteinium and fermiun were observed for the first time. The reports of the next two Plowshare symposia in 1959 and 1964 help record the fascinating development of the scientific uses of neutrons in nuclear explosions. Starting with two 'wheel' experiments in 1958 to measure symmetry of fission in 235-U resonances, the use of external beams of energy-resolved neutrons was expanded on the 'Gnome' experiment in 1961 to include the measurement of neutron capture excitation functions for 238-U, 232-Th

  18. Studying explosive phenomena in astrophysics by the example of gamma-ray bursts and supernovae

    International Nuclear Information System (INIS)

    Filina, Anastasia

    2015-01-01

    The formation of the first stars hundreds of millions of years after the Big-Bang marks the end of the Dark Ages. Currently, we have no direct observations on how the primordial stars formed, but according to modern theory of stellar evolution these stars should be very massive (about 100 Msun) Population III stars have a potential to produce probably most energetic flashes in the Universe - gamma-ray bursts. GRBs may provide one of the most promising methods to probe directly final stage of life of primordial stars. Today's telescopes cannot look far enough into the cosmic past to observe the formation of the first stars, but the new generation of telescopes will test theoretical ideas about the formation of the first stars.Thanks to many years of observations we have good GRB's data -statistics of occurrence, spectrum, light curves. But there are still a lot of questions in the theory of GRBs. We know that GRBs are related to the death of stars and that they are connected with supernovae. So gamma-ray bursts are one of the classes of explosive processes in stellar physics that should have a lot of common with supernovae explosions. In that case GRBs should follow the same physical laws of explosion as supernovae. This work tries to approach the problem of GRBs as a problem of stellar explosion.Necessary instruments of studying stellar explosion were developed as a part of doctoral research: code for solving systems of nuclear reaction equations was incorporated into hydrodynamical code. These tools were applied for supernovae simulations in order to find possible connection with GRBs. Basing on analysis of supernovae simulations spectral analysis of GRBs was performed. (author)

  19. Safety engineering experiments of explosives

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, Noboru

    1987-07-24

    The outline of large scale experiments carried out every year since 1969 to obtain fundamental data and then establish the safety engineering standards concerning the manufacturing, storage and transportation, etc. of all explosives was described. Because it becomes recently difficult to ensure the safety distance in powder magazines and powder plants, the sandwich structure with sand is thought to be suitable as the neighboring barrier walls. The special vertical structure for embankments to provide against a emergency explosion is effective to absorb the blast. Explosion behaviors such as initiating sensitivity, detonation, sympathetic detonation, and shock occurence of the ANFO explosives in place of dynamite and the slurry explosives were studied. The safety engineering standards for the manufacturing and application of explosives were studied to establish because accidents by tabacco fire are not still distinguished. Much data concerning early stage fire fighting, a large quantity of flooding and shock occurence from a assumption of ignition during machining in the propellants manufacturing plant, could be obtained. Basic studies were made to prevent pollution in blasting sites. Collected data are utilized for the safety administration after sufficient discussion. (4 figs, 2 tabs, 3 photos, 17 refs)

  20. Scaling relation and regime map of explosive gas–liquid flow of binary Lennard-Jones particle system

    KAUST Repository

    Inaoka, Hajime

    2012-02-01

    We study explosive gasliquid flows caused by rapid depressurization using a molecular dynamics model of Lennard-Jones particle systems. A unique feature of our model is that it consists of two types of particles: liquid particles, which tend to form liquid droplets, and gas particles, which remain supercritical gaseous states under the depressurization realized by simulations. The system has a pipe-like structure similar to the model of a shock tube. We observed physical quantities and flow regimes in systems with various combinations of initial particle number densities and initial temperatures. It is observed that a physical quantity Q, such as pressure, at position z measured along a pipe-like system at time t follows a scaling relation Q(z,t)=Q(zt) with a scaling function Q(ζ). A similar scaling relation holds for time evolution of flow regimes in a system. These scaling relations lead to a regime map of explosive flows in parameter spaces of local physical quantities. The validity of the scaling relations of physical quantities means that physics of equilibrium systems, such as an equation of state, is applicable to explosive flows in our simulations, though the explosive flows involve highly nonequilibrium processes. In other words, if the breaking of the scaling relations is observed, it means that the explosive flows cannot be fully described by physics of equilibrium systems. We show the possibility of breaking of the scaling relations and discuss its implications in the last section. © 2011 Elsevier B.V. All rights reserved.

  1. Sensitivity to friction for primary explosives

    International Nuclear Information System (INIS)

    Matyáš, Robert; Šelešovský, Jakub; Musil, Tomáš

    2012-01-01

    Highlights: ► The friction sensitivity of 14 samples of primary explosives was determined. ► The same apparatus (small scale BAM) and the same method (probit analysis) was used. ► The crystal shapes and sizes were documented with microscopy. ► Almost all samples are less sensitive than lead azide, which is commercially used. ► The organic peroxides (TATP, DADP, HMTD) are not as sensitive as often reported. - Abstract: The sensitivity to friction for a selection of primary explosives has been studied using a small BAM friction apparatus. The probit analysis was used for the construction of a sensitivity curve for each primary explosive tested. Two groups of primary explosives were chosen for measurement (a) the most commonly used industrially produced primary explosives (e.g. lead azide, tetrazene, dinol, lead styphnate) and (b) the most produced improvised primary explosives (e.g. triacetone triperoxide, hexamethylenetriperoxide diamine, mercury fulminate, acetylides of heavy metals). A knowledge of friction sensitivity is very important for determining manipulation safety for primary explosives. All the primary explosives tested were carefully characterised (synthesis procedure, shape and size of crystals). The sensitivity curves obtained represent a unique set of data, which cannot be found anywhere else in the available literature.

  2. Sensitivity to friction for primary explosives

    Energy Technology Data Exchange (ETDEWEB)

    Matyas, Robert, E-mail: robert.matyas@upce.cz [Institute of Energetic Materials, Faculty of Chemical Technology, University of Pardubice, Pardubice 532 10 (Czech Republic); Selesovsky, Jakub; Musil, Tomas [Institute of Energetic Materials, Faculty of Chemical Technology, University of Pardubice, Pardubice 532 10 (Czech Republic)

    2012-04-30

    Highlights: Black-Right-Pointing-Pointer The friction sensitivity of 14 samples of primary explosives was determined. Black-Right-Pointing-Pointer The same apparatus (small scale BAM) and the same method (probit analysis) was used. Black-Right-Pointing-Pointer The crystal shapes and sizes were documented with microscopy. Black-Right-Pointing-Pointer Almost all samples are less sensitive than lead azide, which is commercially used. Black-Right-Pointing-Pointer The organic peroxides (TATP, DADP, HMTD) are not as sensitive as often reported. - Abstract: The sensitivity to friction for a selection of primary explosives has been studied using a small BAM friction apparatus. The probit analysis was used for the construction of a sensitivity curve for each primary explosive tested. Two groups of primary explosives were chosen for measurement (a) the most commonly used industrially produced primary explosives (e.g. lead azide, tetrazene, dinol, lead styphnate) and (b) the most produced improvised primary explosives (e.g. triacetone triperoxide, hexamethylenetriperoxide diamine, mercury fulminate, acetylides of heavy metals). A knowledge of friction sensitivity is very important for determining manipulation safety for primary explosives. All the primary explosives tested were carefully characterised (synthesis procedure, shape and size of crystals). The sensitivity curves obtained represent a unique set of data, which cannot be found anywhere else in the available literature.

  3. Multilateral haptics-based immersive teleoperation for improvised explosive device disposal

    Science.gov (United States)

    Erickson, David; Lacheray, Hervé; Daly, John

    2013-05-01

    Of great interest to police and military organizations is the development of effective improvised explosive device (IED) disposal (IEDD) technology to aid in activities such as mine field clearing, and bomb disposal. At the same time minimizing risk to personnel. This paper presents new results in the research and development of a next generation mobile immersive teleoperated explosive ordnance disposal system. This system incorporates elements of 3D vision, multilateral teleoperation for high transparency haptic feedback, immersive augmented reality operator control interfaces, and a realistic hardware-in-the-loop (HIL) 3D simulation environment incorporating vehicle and manipulator dynamics for both operator training and algorithm development. In the past year, new algorithms have been developed to facilitate incorporating commercial off-the-shelf (COTS) robotic hardware into the teleoperation system. In particular, a real-time numerical inverse position kinematics algorithm that can be applied to a wide range of manipulators has been implemented, an inertial measurement unit (IMU) attitude stabilization system for manipulators has been developed and experimentally validated, and a voice­operated manipulator control system has been developed and integrated into the operator control station. The integration of these components into a vehicle simulation environment with half-car vehicle dynamics has also been successfully carried out. A physical half-car plant is currently being constructed for HIL integration with the simulation environment.

  4. Confronting Models of Massive Star Evolution and Explosions with Remnant Mass Measurements

    Science.gov (United States)

    Raithel, Carolyn A.; Sukhbold, Tuguldur; Özel, Feryal

    2018-03-01

    The mass distribution of compact objects provides a fossil record that can be studied to uncover information on the late stages of massive star evolution, the supernova explosion mechanism, and the dense matter equation of state. Observations of neutron star masses indicate a bimodal Gaussian distribution, while the observed black hole mass distribution decays exponentially for stellar-mass black holes. We use these observed distributions to directly confront the predictions of stellar evolution models and the neutrino-driven supernova simulations of Sukhbold et al. We find strong agreement between the black hole and low-mass neutron star distributions created by these simulations and the observations. We show that a large fraction of the stellar envelope must be ejected, either during the formation of stellar-mass black holes or prior to the implosion through tidal stripping due to a binary companion, in order to reproduce the observed black hole mass distribution. We also determine the origins of the bimodal peaks of the neutron star mass distribution, finding that the low-mass peak (centered at ∼1.4 M ⊙) originates from progenitors with M ZAMS ≈ 9–18 M ⊙. The simulations fail to reproduce the observed peak of high-mass neutron stars (centered at ∼1.8 M ⊙) and we explore several possible explanations. We argue that the close agreement between the observed and predicted black hole and low-mass neutron star mass distributions provides new, promising evidence that these stellar evolution and explosion models capture the majority of relevant stellar, nuclear, and explosion physics involved in the formation of compact objects.

  5. Fine chemistry

    International Nuclear Information System (INIS)

    Laszlo, P.

    1988-01-01

    The 1988 progress report of the Fine Chemistry laboratory (Polytechnic School, France) is presented. The research programs are centered on the renewal of the organic chemistry most important reactions and on the invention of new, highly efficient and highly selective reactions, by applying low cost reagents and solvents. An important research domain concerns the study and fabrication of new catalysts. They are obtained by means of the reactive sputtering of the metals and metal oxydes thin films. The Monte Carlo simulations of the long-range electrostatic interaction in a clay and the obtention of acrylamides from anhydrous or acrylic ester are summarized. Moreover, the results obtained in the field of catalysis are also given. The published papers and the congress communications are included [fr

  6. Ex-Vessel corium coolability and steam explosion energetics in nordic light water reactors

    International Nuclear Information System (INIS)

    Dinh, T.N.; Ma, W.M.; Karbojian, A.; Kudinov, P.; Tran, C.T.; Hansson, C.R.

    2008-03-01

    This report presents advances and insights from the KTH's study on corium pool heat transfer in the BWR lower head; debris bed formation; steam explosion energetics; thermal hydraulics and coolability in bottom-fed and heterogeneous debris beds. Specifically, for analysis of heat transfer in a BWR lower plenum an advanced threedimensional simulation tool was developed and validated, using a so-called effective convectivity approach and Fluent code platform. An assessment of corium retention and coolability in the reactor pressure vessel (RPV) lower plenum by means of water supplied through the Control Rod Guide Tube (CRGT) cooling system was performed. Simulant material melt experiments were performed in an intermediate temperature range (1300-1600K) on DEFOR test facility to study formation of debris beds in high and low subcooled water pools characteristic of in-vessel and ex-vessel conditions. Results of the DEFOR-E scoping experiments and related analyses strongly suggest that porous beds formed in ex-vessel from a fragmented high-temperature debris is far from homogeneous. Calculation results of bed thermal hydraulics and dryout heat flux with a two-dimensional thermal-hydraulic code give the first basis to evaluate the extent by which macro and micro inhomogeneity can enhance the bed coolability. The development and validation of a model for two-phase natural circulation through a heated porous medium and its application to the coolability analysis of bottom-fed beds enables quantification of the significant effect of dryout heat flux enhancement (by a factor of 80-160%) due to bottom coolant injection. For a qualitative and quantitative understanding of steam explosion, the SHARP system and its image processing methodology were used to characterize the dynamics of a hot liquid (melt) drop fragmentation and the volatile liquid (coolant) vaporization. The experimental results provide a basis to suggest that the melt drop preconditioning is instrumental to the

  7. Ex-Vessel corium coolability and steam explosion energetics in nordic light water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Dinh, T.N.; Ma, W.M.; Karbojian, A.; Kudinov, P.; Tran, C.T.; Hansson, C.R. [Royal Institute of Technology (KTH), (Sweden)

    2008-03-15

    This report presents advances and insights from the KTH's study on corium pool heat transfer in the BWR lower head; debris bed formation; steam explosion energetics; thermal hydraulics and coolability in bottom-fed and heterogeneous debris beds. Specifically, for analysis of heat transfer in a BWR lower plenum an advanced threedimensional simulation tool was developed and validated, using a so-called effective convectivity approach and Fluent code platform. An assessment of corium retention and coolability in the reactor pressure vessel (RPV) lower plenum by means of water supplied through the Control Rod Guide Tube (CRGT) cooling system was performed. Simulant material melt experiments were performed in an intermediate temperature range (1300-1600K) on DEFOR test facility to study formation of debris beds in high and low subcooled water pools characteristic of in-vessel and ex-vessel conditions. Results of the DEFOR-E scoping experiments and related analyses strongly suggest that porous beds formed in ex-vessel from a fragmented high-temperature debris is far from homogeneous. Calculation results of bed thermal hydraulics and dryout heat flux with a two-dimensional thermal-hydraulic code give the first basis to evaluate the extent by which macro and micro inhomogeneity can enhance the bed coolability. The development and validation of a model for two-phase natural circulation through a heated porous medium and its application to the coolability analysis of bottom-fed beds enables quantification of the significant effect of dryout heat flux enhancement (by a factor of 80-160%) due to bottom coolant injection. For a qualitative and quantitative understanding of steam explosion, the SHARP system and its image processing methodology were used to characterize the dynamics of a hot liquid (melt) drop fragmentation and the volatile liquid (coolant) vaporization. The experimental results provide a basis to suggest that the melt drop preconditioning is instrumental to

  8. Explosive performance on the non-proliferation experiment

    Energy Technology Data Exchange (ETDEWEB)

    McKown, T.O. [Los Alamos National Lab., NM (United States)

    1994-12-31

    The Explosive Effects Physics Project at the Los Alamos National Laboratory planned and conducted experiments on the Non-Proliferation Experiment (NPE) as part of its effort to define source functions for seismic waves. Since all investigations were contingent on the performance of the emplaced chemical explosive, an array of diagnostic measurements was fielded in the emplaced explosive. The CORRTEX (COntinuous Reflectometry for Radius vs Time EXperiment) system was used to investigate the explosive initiation and to determine the detonation velocities on three levels and in a number of radial directions. The CORRTEX experiments fielded in the explosive chamber will be described, including a description of the explosive emplacement from the perspective of its impact on the CORRTEX results. The data obtained are reviewed and the resulting detonation velocities are reported. A variation of detonation velocity with depth in the explosive and the apparent underdetonation and overdetonation of the explosive in different radial directions is reported.

  9. Numerical analysis of fragmentation mechanisms in vapor explosions

    Energy Technology Data Exchange (ETDEWEB)

    Koshizuka, Seiichi; Ikeda, Hirokazu; Oka, Yoshiaki [Tokyo Univ., Tokai, Ibaraki (Japan). Nuclear Engineering Research Lab.

    1998-01-01

    Fragmentation of molten metal is the key process in vapor explosions. However this process is so rapid that the mechanisms have not been clarified yet in the experimental studies. Besides, numerical simulation is difficult because we have to analyze water, steam and molten metal simultaneously with evaporation and fragmentation. The authors have been developing a new numerical method, the Moving Particle Semi-implicit (MPS) method, based on moving particles and their interactions. Grids are not necessary. Incompressible flows with fragmentation on free surfaces have been calculated successfully using the MPS method. In the present study numerical simulation of the fragmentation processes using the MPS method is carried out to investigate the mechanisms. A numerical model to calculate evaporation from water to steam is developed. In this model, new particles are generated on water-steam interfaces. Effect of evaporation is also investigated. Growth of the filament is not accelerated when the normal evaporation is considered. This is because the normal evaporation needs a longer time than the moment of the jet impingement, though the filament growth is decided in this moment. Next, rapid evaporation based on spontaneous nucleation is considered. The filament growth is markedly accelerated. This result is consistent with the experimental fact that the spontaneous nucleation temperature is a necessary condition of small-scale vapor explosions. (J.P.N.)

  10. Organic chemistry in Titan's atmosphere

    Science.gov (United States)

    Scattergood, T.

    1982-01-01

    Laboratory photochemical simulations and other types of chemical simulations are discussed. The chemistry of methane, which is the major known constituent of Titan's atmosphere was examined with stress on what can be learned from photochemistry and particle irradiation. The composition of dust that comprises the haze layer was determined. Isotope fractionation in planetary atmospheres is also discussed.

  11. The behavior limestone under explosive load

    Science.gov (United States)

    Orlov, M. Yu; Orlova, Yu N.; Bogomolov, G. N.

    2016-11-01

    Limestone behavior under explosive loading was investigated. The behavior of the limestone by the action of the three types of explosives, including granular, ammonite and emulsion explosives was studied in detail. The shape and diameter of the explosion craters were obtained. The observed fragments after the blast have been classified as large, medium and small fragments. Three full-scale experiments were carried out. The research results can be used as a qualitative test for the approbation of numerical methods.

  12. Rapid expansion and fracture of metallic cylinders driven by explosive loads

    International Nuclear Information System (INIS)

    Hiroe, T.; Fujiwara, K.; Abe, T.; Yoshida, M.

    2004-01-01

    Smooth walled tubular specimens of stainless steel and low-carbon steels were explosively expanded to fragmentation. The driver was a column of the high explosive PETN inserted into the central bore and initiated by exploding a fine copper wire using a discharge current from a high-voltage capacitor bank. The variation of wall thickness and the effect of different explosive driver diameters are reported. A fully charged casing model was also exploded with initiation at the end surface for comparison. Streak and framing photos show both radially and axially symmetric expansion of cylinders at average strain rates of above 104 s-1 and a wall velocity of 417-1550 m/s. Some framing photos indicate the initiation and spacing of fractures during the bursting of the cylinders. Hydro codes have been applied to simulate the experimental behavior of the cylinders, examining numerical stresses, deformation and fracture criteria. Most of the fragments were successfully recovered inside a cushion-filled chamber, and the circumferential fracture spacing of measured fragments is investigated using a fragmentation model

  13. Nuclear explosions and their effects

    Energy Technology Data Exchange (ETDEWEB)

    1958-01-01

    A brief historical background is given of the development of the atomic bomb. Also included is an account of the Hiroshima-Nagasaki bombing, plus some information on the testing and production of nuclear weapons by the United States, United Kingdom, and Russia. More detailed consideration is given to the following: the scientific principles of fission and fusion explosions; the energy released in fission and the radioactivity of fission products; blast, thermal, and radiologicalal effects of nuclear explosions; long-term radiological hazards from fall-out; and genetic effects of nuclear explosions. A brief account is given of the fission chain process, the concept of critical size, and the principles of implosion as applied to nuclear explosions. Limited information is presented on the controlled release of thermonuclear energy and catalyzed fusion reaction. Discussions are included on dose rates from radiation sources inside and outside the body, the effect of nuclear explosions on the weather, and the contamination of fish and marine organisms.

  14. Illustration of the Alliances platform chemistry/transport coupling capacities through the simulation of a cement/clay interaction

    International Nuclear Information System (INIS)

    Dimier, A.; Michau, N.; Montarnal, Ph.; Corrihons, F.

    2003-01-01

    Safety studies in a subsurface environment and in an underground waste disposal necessitate numerical tools for reactive transport modelling. In these systems, hydrogeological and chemical processes are closely related and their interdependence must be analysed to study migration of species. We will illustrate here the capacities of the Alliances tool to simulate such a phenomenology by studying the evolution of a clay/cement interface over time. The goal being defined, the two main employed software to build up a multidimensional tool have been chosen, namely PhreeqC and Chess for chemistry. A common model has been developed whose aim is to allow models comparison while switching between the chemistry tools. For transport, Castem and Mt3d-99 have been introduced with the same philosophy of structure. It is worth noting that other tools could be introduced, the only requirement being to satisfy the specific data-model and building up the appropriate methods. Qualification cases have been built up to define the platform application field. It has been defined with one and two dimensional cases enabling a comparison with analytic solutions or an intercomparison with other reactive transport codes. To illustrate this in the chemistry coupling field, we focus on a clay cement interface with an ion exchange linked to the Ca-montmorillonite. This case has been defined at ANDRA to be used as a reference test case for chemistry coupling validation. Results show a good agreement between platform results and whose of PhreeqC with its own internal coupling. The clay/cement interface is reproduced with the same accuracy

  15. Phenomenological modelling of steam explosions

    International Nuclear Information System (INIS)

    Corradini, M.L.; Drumheller, D.S.

    1980-01-01

    During a hypothetical core meltdown accident, an important safety issue to be addressed is the potential for steam explosions. This paper presents analysis and modelling of experimental results. There are four observations that can be drawn from the analysis: (1) vapor explosions are suppressed by noncondensible gases generated by fuel oxidation, by high ambient pressure, and by high water temperatures; (2) these effects appear to be trigger-related in that an explosion can again be induced in some cases by increasing the trigger magnitude; (3) direct fuel liquid-coolant liquid contact can explain small scale fuel fragmentation; (4) heat transfer during the expansion phase of the explosion can reduce the work potential

  16. Explosions and static electricity

    DEFF Research Database (Denmark)

    Jonassen, Niels M

    1995-01-01

    The paper deals with the problem of electrostatic discharges as causes of ignition of vapor/gas and dust/gas mixtures. A series of examples of static-caused explosions will be discussed. The concepts of explosion limits, the incendiveness of various discharge types and safe voltages are explained...

  17. Solar cycle variations of stratospheric ozone and temperature in simulations of a coupled chemistry-climate model

    Directory of Open Access Journals (Sweden)

    J. Austin

    2007-01-01

    Full Text Available The results from three 45-year simulations of a coupled chemistry climate model are analysed for solar cycle influences on ozone and temperature. The simulations include UV forcing at the top of the atmosphere, which includes a generic 27-day solar rotation effect as well as the observed monthly values of the solar fluxes. The results are analysed for the 27-day and 11-year cycles in temperature and ozone. In accordance with previous results, the 27-day cycle results are in good qualitative agreement with observations, particularly for ozone. However, the results show significant variations, typically a factor of two or more in sensitivity to solar flux, depending on the solar cycle. In the lower and middle stratosphere we show good agreement also between the modelled and observed 11-year cycle results for the ozone vertical profile averaged over low latitudes. In particular, the minimum in solar response near 20 hPa is well simulated. In comparison, experiments of the model with fixed solar phase (solar maximum/solar mean and climatological sea surface temperatures lead to a poorer simulation of the solar response in the ozone vertical profile, indicating the need for variable phase simulations in solar sensitivity experiments. The role of sea surface temperatures and tropical upwelling in simulating the ozone minimum response are also discussed.

  18. Ammonium nitrate explosion hazards

    Directory of Open Access Journals (Sweden)

    Negovanović Milanka

    2015-01-01

    Full Text Available Ammonium nitrate (AN primarily is used as a fertilizer but it is also very important compound in the production of industrial explosives. The application of ammonium nitrate in the production of industrial explosives was related with the early era of Nobel dynamite and widely increased with the appearance of blasting agents such as ANFO and Slurry, in the middle of the last Century. Throughout the world millions of tons of ammonium nitrate are produced annually and handled without incident. Although ammonium nitrate generally is used safely, accidental explosions involving AN have high impact resulting in loss of lives and destruction of property. The paper presents the basic properties of ammonium nitrate as well as hazards in handling of ammonium nitrate in order to prevent accidents. Several accidents with explosions of ammonium nitrate resulted in catastrophic consequences are listed in the paper as examples of non-compliance with prescribed procedures.

  19. Uncertainty estimation and ensemble forecast with a chemistry-transport model - Application to air-quality modeling and simulation

    International Nuclear Information System (INIS)

    Mallet, Vivien

    2005-01-01

    The thesis deals with the evaluation of a chemistry-transport model, not primarily with classical comparisons to observations, but through the estimation of its a priori uncertainties due to input data, model formulation and numerical approximations. These three uncertainty sources are studied respectively on the basis of Monte Carlos simulations, multi-models simulations and numerical schemes inter-comparisons. A high uncertainty is found, in output ozone concentrations. In order to overtake the limitations due to the uncertainty, a solution is ensemble forecast. Through combinations of several models (up to forty-eight models) on the basis of past observations, the forecast can be significantly improved. The achievement of this work has also led to develop the innovative modelling-system Polyphemus. (author) [fr

  20. Explosive Characteristics of Carbonaceous Nanoparticles

    Science.gov (United States)

    Turkevich, Leonid; Fernback, Joseph; Dastidar, Ashok

    2013-03-01

    Explosion testing has been performed on 20 codes of carbonaceous particles. These include SWCNTs (single-walled carbon nanotubes), MWCNTs (multi-walled carbon nanotubes), CNFs (carbon nanofibers), graphene, diamond, fullerene, carbon blacks and graphites. Explosion screening was performed in a 20 L explosion chamber (ASTM E1226-10 protocol), at a (dilute) concentration of 500 g/m3, using a 5 kJ ignition source. Time traces of overpressure were recorded. Samples exhibited overpressures of 5-7 bar, and deflagration index KSt = V1/3 (dp/pt)max ~ 10 - 80 bar-m/s, which places these materials in European Dust Explosion Class St-1 (similar to cotton and wood dust). There was minimal variation between these different materials. The explosive characteristics of these carbonaceous powders are uncorrelated with particle size (BET specific surface area). Additional tests were performed on selected materials to identify minimum explosive concentration [MEC]. These materials exhibit MEC ~ 101 -102 g/m3 (lower than the MEC for coals). The concentration scans confirm that the earlier screening was performed under fuel-rich conditions (i.e. the maximum over-pressure and deflagration index exceed the screening values); e.g. the true fullerene KSt ~ 200 bar-m/s, placing it borderline St-1/St-2. Work supported through the NIOSH Nanotechnology Research Center (NTRC)

  1. Modelling of fast jet formation under explosion collision of two-layer alumina/copper tubes

    Directory of Open Access Journals (Sweden)

    I Balagansky

    2017-09-01

    Full Text Available Under explosion collapse of two-layer tubes with an outer layer of high-modulus ceramics and an inner layer of copper, formation of a fast and dense copper jet is plausible. We have performed a numerical simulation of the explosion collapse of a two-layer alumina/copper tube using ANSYS AUTODYN software. The simulation was performed in a 2D-axis symmetry posting on an Eulerian mesh of 3900x1200 cells. The simulation results indicate two separate stages of the tube collapse process: the nonstationary and the stationary stage. At the initial stage, a non-stationary fragmented jet is moving with the velocity of leading elements up to 30 km/s. The collapse velocity of the tube to the symmetry axis is about 2 km/s, and the pressure in the contact zone exceeds 700 GPa. During the stationary stage, a dense jet is forming with the velocity of 20 km/s. Temperature of the dense jet is about 2000 K, jet failure occurs when the value of effective plastic deformation reaches 30.

  2. How to determine the handedness of single molecules using Coulomb explosion imaging

    International Nuclear Information System (INIS)

    Pitzer, Martin

    2017-01-01

    This tutorial is based on a doctoral thesis that was shortlisted for the 2016 AMOP dissertation prize of the German Physical Society (DPG). The principal achievement of the thesis was to use Coulomb explosion imaging (CEI) to determine the microscopic handedness (‘chirality’) of molecular structures on a single-molecule level. It thus shows how a technique developed in atomic physics can address a long-standing problem in chemistry. Owing to these disparate backgrounds, the tutorial has two facets: on the one hand, the history of molecular chirality and recent developments are very briefly reviewed. On the other hand, an account is given of different experimental approaches to CEI, on the physical processes in light-induced Coulomb explosion and—most importantly—on the aspects that are relevant when designing and performing such an experiment. As structural chirality occurs only in polyatomic molecules, special attention will be given to multiple ionization and multi-coincidence measurements. A short discussion of the results presented in earlier papers is given, followed by an outlook on experiments that are under way or can realistically be performed within the next years. (phd tutorial)

  3. 27 CFR 555.181 - Reporting of plastic explosives.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2010-04-01 2010-04-01 false Reporting of plastic..., FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE EXPLOSIVES COMMERCE IN EXPLOSIVES Marking of Plastic Explosives § 555.181 Reporting of plastic explosives. All persons, other than an agency of the United States...

  4. Incorporating damage mechanics into explosion simulation models

    International Nuclear Information System (INIS)

    Sammis, C.G.

    1993-01-01

    The source region of an underground explosion is commonly modeled as a nested series of shells. In the innermost open-quotes hydrodynamic regimeclose quotes pressures and temperatures are sufficiently high that the rock deforms as a fluid and may be described using a PVT equation of state. Just beyond the hydrodynamic regime, is the open-quotes non-linear regimeclose quotes in which the rock has shear strength but the deformation is nonlinear. This regime extends out to the open-quotes elastic radiusclose quotes beyond which the deformation is linear. In this paper, we develop a model for the non-linear regime in crystalline source rock where the nonlinearity is mostly due to fractures. We divide the non-linear regime into a open-quotes damage regimeclose quotes in which the stresses are sufficiently high to nucleate new fractures from preexisting ones and a open-quotes crack-slidingclose quotes regime where motion on preexisting cracks produces amplitude dependent attenuation and other non-linear effects, but no new cracks are nucleated. The boundary between these two regimes is called the open-quotes damage radius.close quotes The micromechanical damage mechanics recently developed by Ashby and Sammis (1990) is used to write an analytic expression for the damage radius in terms of the initial fracture spectrum of the source rock, and to develop an algorithm which may be used to incorporate damage mechanics into computer source models for the damage regime. Effects of water saturation and loading rate are also discussed

  5. Shock-induced chemistry in organic materials

    Energy Technology Data Exchange (ETDEWEB)

    Dattelbaum, Dana M [Los Alamos National Laboratory; Sheffield, Steve [Los Alamos National Laboratory; Engelke, Ray [Los Alamos National Laboratory; Manner, Virginia [Los Alamos National Laboratory; Chellappa, Raja [Los Alamos National Laboratory; Yoo, Choong - Shik [WASHINGTON STATE UNIV

    2011-01-20

    The combined 'extreme' environments of high pressure, temperature, and strain rates, encountered under shock loading, offer enormous potential for the discovery of new paradigms in chemical reactivity not possible under more benign conditions. All organic materials are expected to react under these conditions, yet we currently understand very little about the first bond-breaking steps behind the shock front, such as in the shock initiation of explosives, or shock-induced reactivity of other relevant materials. Here, I will present recent experimental results of shock-induced chemistry in a variety of organic materials under sustained shock conditions. A comparison between the reactivity of different structures is given, and a perspective on the kinetics of reaction completion under shock drives.

  6. Dependence of hotspot initiation on void distribution in high explosive crystals simulated with molecular dynamics

    Science.gov (United States)

    Herring, Stuart Davis

    Microscopic defects may dramatically affect the susceptibility of high explosives to shock initiation. Such defects redirect the shock's energy and become hotspots (concentrations of stress and heat) that can initiate chemical reactions. Sufficiently large or numerous defects may produce a self-sustaining deflagration or even detonation from a shock notably too weak to detonate defect-free samples. The effects of circular or spherical voids on the shock sensitivity of a model (two- or three-dimensional) high explosive crystal are considered. We simulate a piston impact using molecular dynamics with a Reactive Empirical Bond Order (REBO) model potential for a sub-micron, sub-ns exothermic reaction in a diatomic molecular solid. In both dimensionalities, the probability of initiating chemical reactions rises more suddenly with increasing piston velocity for larger voids that collapse more deterministically. A void of even 10 nm radius (˜39 interatomic spacings) reduces the minimum initiating velocity by a factor of 4 (8 in 3D). The transition at larger velocities to detonation is studied in micron-long samples with a single void (and its periodic images). Reactions during the shock traversal increase rapidly with velocity, then become a reliable detonation. In 2D, a void of radius 2.5 nm reduces the critical velocity by 10% from the perfect crystal; a Pop plot of the detonation delays at higher velocities shows a characteristic pressure dependence. 3D samples are more likely to react but less to detonate. In square lattices of voids, reducing the (common) void radius or increasing the porosity without changing the other parameter causes the hotspots to consume the material faster and detonation to occur sooner and at lower velocities. Early behavior is seen to follow a very simple ignition and growth model; the pressure exponents are more realistic than with single voids. The hotspots collectively develop a broad pressure wave (a sonic, diffuse deflagration front

  7. Reduction of radioactivity produced by nuclear explosives

    Energy Technology Data Exchange (ETDEWEB)

    Lessler, Richard M [Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)

    1970-05-15

    Four main sources contribute to the radioactivity produced by a nuclear explosive: 1. Fission products from the nuclear explosive, 2. Fusion products from the nuclear explosive, 3. Induced radioactivity in the nuclear explosive, 4. Induced radioactivity in the environment. This paper will summarize some of the work done at the Lawrence Radiation Laboratory at Livermore to reduce the radioactivity from these sources to levels acceptable for peaceful applications. Although it is theoretically possible to have no radioactivity produced by nuclear explosives, this goal has not been achieved.

  8. Interactive ozone and methane chemistry in GISS-E2 historical and future climate simulations

    Directory of Open Access Journals (Sweden)

    D. T. Shindell

    2013-03-01

    Full Text Available The new generation GISS climate model includes fully interactive chemistry related to ozone in historical and future simulations, and interactive methane in future simulations. Evaluation of ozone, its tropospheric precursors, and methane shows that the model captures much of the large-scale spatial structure seen in recent observations. While the model is much improved compared with the previous chemistry-climate model, especially for ozone seasonality in the stratosphere, there is still slightly too rapid stratospheric circulation, too little stratosphere-to-troposphere ozone flux in the Southern Hemisphere and an Antarctic ozone hole that is too large and persists too long. Quantitative metrics of spatial and temporal correlations with satellite datasets as well as spatial autocorrelation to examine transport and mixing are presented to document improvements in model skill and provide a benchmark for future evaluations. The difference in radiative forcing (RF calculated using modeled tropospheric ozone versus tropospheric ozone observed by TES is only 0.016 W m−2. Historical 20th Century simulations show a steady increase in whole atmosphere ozone RF through 1970 after which there is a decrease through 2000 due to stratospheric ozone depletion. Ozone forcing increases throughout the 21st century under RCP8.5 owing to a projected recovery of stratospheric ozone depletion and increases in methane, but decreases under RCP4.5 and 2.6 due to reductions in emissions of other ozone precursors. RF from methane is 0.05 to 0.18 W m−2 higher in our model calculations than in the RCP RF estimates. The surface temperature response to ozone through 1970 follows the increase in forcing due to tropospheric ozone. After that time, surface temperatures decrease as ozone RF declines due to stratospheric depletion. The stratospheric ozone depletion also induces substantial changes in surface winds and the Southern Ocean circulation, which may play a role in

  9. Simulating Supernova Light Curves

    Energy Technology Data Exchange (ETDEWEB)

    Even, Wesley Paul [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dolence, Joshua C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-05

    This report discusses supernova light simulations. A brief review of supernovae, basics of supernova light curves, simulation tools used at LANL, and supernova results are included. Further, it happens that many of the same methods used to generate simulated supernova light curves can also be used to model the emission from fireballs generated by explosions in the earth’s atmosphere.

  10. Simulating Supernova Light Curves

    International Nuclear Information System (INIS)

    Even, Wesley Paul; Dolence, Joshua C.

    2016-01-01

    This report discusses supernova light simulations. A brief review of supernovae, basics of supernova light curves, simulation tools used at LANL, and supernova results are included. Further, it happens that many of the same methods used to generate simulated supernova light curves can also be used to model the emission from fireballs generated by explosions in the earth's atmosphere.

  11. 2D and 3D numerical modeling of seismic waves from explosion sources

    International Nuclear Information System (INIS)

    McLaughlin, K.L.; Stevens, J.L.; Barker, T.G.; Shkoller, B.; Day, S.M.

    1993-01-01

    Over the last decade, nonlinear and linear 2D axisymmetric finite difference codes have been used in conjunction with far-field seismic Green's functions to simulate seismic waves from a variety of sources. In this paper we briefly review some of the results and conclusions that have resulted from numerical simulations and explosion modeling in support of treaty verification research at S-CUBED in the last decade. We then describe in more detail the results from two recent projects. Our goal is to provide a flavor for the kinds of problems that can be examined with numerical methods for modeling excitation of seismic waves from explosions. Two classes of problems have been addressed; nonlinear and linear near-source interactions. In both classes of problems displacements and tractions are saved on a closed surface in the linear region and the representation theorem is used to propagate the seismic waves to the far-field

  12. PROGENITOR-EXPLOSION CONNECTION AND REMNANT BIRTH MASSES FOR NEUTRINO-DRIVEN SUPERNOVAE OF IRON-CORE PROGENITORS

    Energy Technology Data Exchange (ETDEWEB)

    Ugliano, Marcella; Janka, Hans-Thomas; Marek, Andreas [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany); Arcones, Almudena [Institut fuer Kernphysik, Technische Universitaet Darmstadt, Schlossgartenstr. 2, D-64289 Darmstadt (Germany)

    2012-09-20

    We perform hydrodynamic supernova (SN) simulations in spherical symmetry for over 100 single stars of solar metallicity to explore the progenitor-explosion and progenitor-remnant connections established by the neutrino-driven mechanism. We use an approximative treatment of neutrino transport and replace the high-density interior of the neutron star (NS) by an inner boundary condition based on an analytic proto-NS core-cooling model, whose free parameters are chosen such that explosion energy, nickel production, and energy release by the compact remnant of progenitors around 20 M{sub Sun} are compatible with SN 1987A. Thus, we are able to simulate the accretion phase, initiation of the explosion, subsequent neutrino-driven wind phase for 15-20 s, and the further evolution of the blast wave for hours to days until fallback is completed. Our results challenge long-standing paradigms. We find that remnant mass, launch time, and properties of the explosion depend strongly on the stellar structure and exhibit large variability even in narrow intervals of the progenitors' zero-age main-sequence mass. While all progenitors with masses below {approx}15 M{sub Sun} yield NSs, black hole (BH) as well as NS formation is possible for more massive stars, where partial loss of the hydrogen envelope leads to weak reverse shocks and weak fallback. Our NS baryonic masses of {approx}1.2-2.0 M{sub Sun} and BH masses >6 M{sub Sun} are compatible with a possible lack of low-mass BHs in the empirical distribution. Neutrino heating accounts for SN energies between some 10{sup 50} erg and {approx}2 Multiplication-Sign 10{sup 51} erg but can hardly explain more energetic explosions and nickel masses higher than 0.1-0.2 M{sub Sun }. These seem to require an alternative SN mechanism.

  13. Simulating chemistry using quantum computers.

    Science.gov (United States)

    Kassal, Ivan; Whitfield, James D; Perdomo-Ortiz, Alejandro; Yung, Man-Hong; Aspuru-Guzik, Alán

    2011-01-01

    The difficulty of simulating quantum systems, well known to quantum chemists, prompted the idea of quantum computation. One can avoid the steep scaling associated with the exact simulation of increasingly large quantum systems on conventional computers, by mapping the quantum system to another, more controllable one. In this review, we discuss to what extent the ideas in quantum computation, now a well-established field, have been applied to chemical problems. We describe algorithms that achieve significant advantages for the electronic-structure problem, the simulation of chemical dynamics, protein folding, and other tasks. Although theory is still ahead of experiment, we outline recent advances that have led to the first chemical calculations on small quantum information processors.

  14. Explosions of Thorne-Żytkow objects

    Science.gov (United States)

    Moriya, Takashi J.

    2018-03-01

    We propose that massive Thorne-Żytkow objects can explode. A Thorne-Żytkow object is a theoretically predicted star that has a neutron core. When nuclear reactions supporting a massive Thorne-Żytkow object terminate, a strong accretion occurs towards the central neutron core. The accretion rate is large enough to sustain a super-Eddington accretion towards the neutron core. The neutron core may collapse to a black hole after a while. A strong large-scale outflow or a jet can be launched from the super-Eddington accretion disc and the collapsing Thorne-Żytkow object can be turned into an explosion. The ejecta have about 10 M⊙ but the explosion energy depends on when the accretion is suppressed. We presume that the explosion energy could be as low as ˜1047 erg and such a low-energy explosion could be observed like a failed supernova. The maximum possible explosion energy is ˜1052 erg and such a high-energy explosion could be observed as an energetic Type II supernova or a superluminous supernova. Explosions of Thorne-Żytkow objects may provide a new path to spread lithium and other heavy elements produced through the irp process such as molybdenum in the Universe.

  15. Explosives mimic for testing, training, and monitoring

    Science.gov (United States)

    Reynolds, John G.; Durban, Matthew M.; Gash, Alexander E.; Grapes, Michael D.; Kelley, Ryan S.; Sullivan, Kyle T.

    2018-02-13

    Additive Manufacturing (AM) is used to make mimics for explosives. The process uses mixtures of explosives and matrices commonly used in AM. The explosives are formulated into a mixture with the matrix and printed using AM techniques and equipment. The explosive concentrations are kept less than 10% by wt. of the mixture to conform to requirements of shipping and handling.

  16. Simulation of Metal Particulates in High Energetic Materials

    Science.gov (United States)

    2015-05-28

    temperatures and pressures disintegrate the carbon- fiber casing, thus not producing any fragments. These carbon-fiber casing warheads are a solution...Polymer-Bonded Explosive (PBX) and Livermore’s High-Energy Explosive (LX) are examples of ex- plosives that use “ plastic ” as a binder material. Other...simulation data to empirical data does not provide any benefit to this research due to the complexity of plastically bonded explosives like PBX9501. The

  17. Effect of type of explosives and physical-mechanical properties of explosive rock on formation of toxic gases in atmosphere of shafts

    Science.gov (United States)

    Mindeli, E. O.; Khudyakov, M. Y.

    1981-01-01

    The quality of toxic gases formed during explosive work in underground shafts depends upon the type of explosives and the conditions of explosion. Several types of explosives and rocks were examined. All remaining conditions were maintained the same (sandy-argillaceous stemming, electrical method of explosions, diameter of blast holes, and the direct triggering of charges).

  18. Determination of concentration of radon, volatile organic compounds (VOC) and water chemistry in springs near to Popocatepetl volcano

    International Nuclear Information System (INIS)

    Pena, P.; Segovia, N.; Lopez M, B.E.; Cisniega, G.; Valdes, C.; Armienta, M.A.; Mena, M.

    2004-01-01

    Popocatepetl volcano is a high-risk active volcano in Central Mexico where the highest population density in the country is settled. Radon in the soil and groundwater together with water chemistry from samples of nearby springs is analysed as a function of the 2002-2003 volcanic activity. Soil radon indicated fluctuations related both the meteorological parameters and sporadic explosive events. Groundwater radon showed essentially differences in concentration due to the specific characteristics of the studied springs. Water chemistry showed stability along the monitoring period indicating also differences between springs. No anthropogenic pollution from volatile organic compounds was observed. (Author)

  19. Ultrafast Coulomb explosion of a diiodomethane molecule induced by an X-ray free-electron laser pulse.

    Science.gov (United States)

    Takanashi, Tsukasa; Nakamura, Kosuke; Kukk, Edwin; Motomura, Koji; Fukuzawa, Hironobu; Nagaya, Kiyonobu; Wada, Shin-Ichi; Kumagai, Yoshiaki; Iablonskyi, Denys; Ito, Yuta; Sakakibara, Yuta; You, Daehyun; Nishiyama, Toshiyuki; Asa, Kazuki; Sato, Yuhiro; Umemoto, Takayuki; Kariyazono, Kango; Ochiai, Kohei; Kanno, Manabu; Yamazaki, Kaoru; Kooser, Kuno; Nicolas, Christophe; Miron, Catalin; Asavei, Theodor; Neagu, Liviu; Schöffler, Markus; Kastirke, Gregor; Liu, Xiao-Jing; Rudenko, Artem; Owada, Shigeki; Katayama, Tetsuo; Togashi, Tadashi; Tono, Kensuke; Yabashi, Makina; Kono, Hirohiko; Ueda, Kiyoshi

    2017-08-02

    Coulomb explosion of diiodomethane CH 2 I 2 molecules irradiated by ultrashort and intense X-ray pulses from SACLA, the Japanese X-ray free electron laser facility, was investigated by multi-ion coincidence measurements and self-consistent charge density-functional-based tight-binding (SCC-DFTB) simulations. The diiodomethane molecule, containing two heavy-atom X-ray absorbing sites, exhibits a rather different charge generation and nuclear motion dynamics compared to iodomethane CH 3 I with only a single heavy atom, as studied earlier. We focus on charge creation and distribution in CH 2 I 2 in comparison to CH 3 I. The release of kinetic energy into atomic ion fragments is also studied by comparing SCC-DFTB simulations with the experiment. Compared to earlier simulations, several key enhancements are made, such as the introduction of a bond axis recoil model, where vibrational energy generated during charge creation processes induces only bond stretching or shrinking. We also propose an analytical Coulomb energy partition model to extract the essential mechanism of Coulomb explosion of molecules from the computed and the experimentally measured kinetic energies of fragment atomic ions by partitioning each pair Coulomb interaction energy into two ions of the pair under the constraint of momentum conservation. Effective internuclear distances assigned to individual fragment ions at the critical moment of the Coulomb explosion are then estimated from the average kinetic energies of the ions. We demonstrate, with good agreement between the experiment and the SCC-DFTB simulation, how the more heavily charged iodine fragments and their interplay define the characteristic features of the Coulomb explosion of CH 2 I 2 . The present study also confirms earlier findings concerning the magnitude of bond elongation in the ultrashort X-ray pulse duration, showing that structural damage to all but C-H bonds does not develop to a noticeable degree in the pulse length of ∼10

  20. A solution to the rule explosion in the fuzzy inverted pendulum

    Directory of Open Access Journals (Sweden)

    Peng Ye

    2017-08-01

    Full Text Available Granulated thought is introduced in this paper,which considers the fuzzy rules as fuzzy grain point and the simulation experiment is carried out.The results show that this method can not only archive the desired control effect,but also reduce the complexity of the system effectively,thereby solve the fuzzy controller rule explosion problem due to rules excessive.

  1. Molecular Outflows: Explosive versus Protostellar

    Energy Technology Data Exchange (ETDEWEB)

    Zapata, Luis A.; Rodríguez, Luis F.; Palau, Aina; Loinard, Laurent [Instituto de Radioastronomía y Astrofísica, UNAM, Apdo. Postal 3-72 (Xangari), 58089 Morelia, Michoacán, México (Mexico); Schmid-Burgk, Johannes [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121, Bonn (Germany)

    2017-02-10

    With the recent recognition of a second, distinctive class of molecular outflows, namely the explosive ones not directly connected to the accretion–ejection process in star formation, a juxtaposition of the morphological and kinematic properties of both classes is warranted. By applying the same method used in Zapata et al., and using {sup 12}CO( J = 2-1) archival data from the Submillimeter Array, we contrast two well-known explosive objects, Orion KL and DR21, to HH 211 and DG Tau B, two flows representative of classical low-mass protostellar outflows. At the moment, there are only two well-established cases of explosive outflows, but with the full availability of ALMA we expect that more examples will be found in the near future. The main results are the largely different spatial distributions of the explosive flows, consisting of numerous narrow straight filament-like ejections with different orientations and in almost an isotropic configuration, the redshifted with respect to the blueshifted components of the flows (maximally separated in protostellar, largely overlapping in explosive outflows), the very-well-defined Hubble flow-like increase of velocity with distance from the origin in the explosive filaments versus the mostly non-organized CO velocity field in protostellar objects, and huge inequalities in mass, momentum, and energy of the two classes, at least for the case of low-mass flows. Finally, all the molecular filaments in the explosive outflows point back to approximately a central position (i.e., the place where its “exciting source” was located), contrary to the bulk of the molecular material within the protostellar outflows.

  2. STOCHASTIC NATURE OF GRAVITATIONAL WAVES FROM SUPERNOVA EXPLOSIONS WITH STANDING ACCRETION SHOCK INSTABILITY

    International Nuclear Information System (INIS)

    Kotake, Kei; Iwakami, Wakana; Ohnishi, Naofumi; Yamada, Shoichi

    2009-01-01

    We study the properties of gravitational waves (GWs) based on three-dimensional (3D) simulations, which demonstrate neutrino-driven explosions aided by standing accretion shock instability (SASI). Pushed by evidence supporting slow rotation prior to core collapse, we focus on the asphericities in neutrino emissions and matter motions outside the protoneutron star. By performing a ray-tracing calculation in 3D, we estimate accurately the gravitational waveforms from anisotropic neutrino emissions. In contrast to the previous work assuming axisymmetry, we find that the gravitational waveforms vary much more stochastically because the explosion anisotropies depend sensitively on the growth of SASI which develops chaotically in all directions. Our results show that the GW spectrum has its peak near ∼100 Hz, reflecting SASI-induced matter overturns of ∼O(10) ms. We point out that the detection of such signals, possibly visible to the LIGO-class detectors for a Galactic supernova, could be an important probe into the long-veiled explosion mechanism.

  3. Premixed flame chemistry of a gasoline primary reference fuel surrogate

    KAUST Repository

    Selim, Hatem; Mohamed, Samah; Hansen, Nils; Sarathy, Mani

    2017-01-01

    Investigating the combustion chemistry of gasoline surrogate fuels promises to improve detailed reaction mechanisms used for simulating their combustion. In this work, the combustion chemistry of one of the simplest, but most frequently used

  4. Suppression of stratified explosive interactions

    Energy Technology Data Exchange (ETDEWEB)

    Meeks, M.K.; Shamoun, B.I.; Bonazza, R.; Corradini, M.L. [Wisconsin Univ., Madison, WI (United States). Dept. of Nuclear Engineering and Engineering Physics

    1998-01-01

    Stratified Fuel-Coolant Interaction (FCI) experiments with Refrigerant-134a and water were performed in a large-scale system. Air was uniformly injected into the coolant pool to establish a pre-existing void which could suppress the explosion. Two competing effects due to the variation of the air flow rate seem to influence the intensity of the explosion in this geometrical configuration. At low flow rates, although the injected air increases the void fraction, the concurrent agitation and mixing increases the intensity of the interaction. At higher flow rates, the increase in void fraction tends to attenuate the propagated pressure wave generated by the explosion. Experimental results show a complete suppression of the vapor explosion at high rates of air injection, corresponding to an average void fraction of larger than 30%. (author)

  5. Turbocharged molecular discovery of OLED emitters: from high-throughput quantum simulation to highly efficient TADF devices

    Science.gov (United States)

    Gómez-Bombarelli, Rafael; Aguilera-Iparraguirre, Jorge; Hirzel, Timothy D.; Ha, Dong-Gwang; Einzinger, Markus; Wu, Tony; Baldo, Marc A.; Aspuru-Guzik, Alán.

    2016-09-01

    Discovering new OLED emitters requires many experiments to synthesize candidates and test performance in devices. Large scale computer simulation can greatly speed this search process but the problem remains challenging enough that brute force application of massive computing power is not enough to successfully identify novel structures. We report a successful High Throughput Virtual Screening study that leveraged a range of methods to optimize the search process. The generation of candidate structures was constrained to contain combinatorial explosion. Simulations were tuned to the specific problem and calibrated with experimental results. Experimentalists and theorists actively collaborated such that experimental feedback was regularly utilized to update and shape the computational search. Supervised machine learning methods prioritized candidate structures prior to quantum chemistry simulation to prevent wasting compute on likely poor performers. With this combination of techniques, each multiplying the strength of the search, this effort managed to navigate an area of molecular space and identify hundreds of promising OLED candidate structures. An experimentally validated selection of this set shows emitters with external quantum efficiencies as high as 22%.

  6. In-vessel coolability and steam explosion in Nordic BWRs

    International Nuclear Information System (INIS)

    Ma, W.; Hansson, R.; Li, L.; Kudinov, P.; Cadinu, F.; Tran, C-.T.

    2010-05-01

    The INCOSE project is to reduce the uncertainty in quantification of steam explosion risk and in-vessel coolability in Nordic BWR plants with the cavity flooding as a severe accident management (SAM) measure. During 2009 substantial advances and new insights into physical mechanisms were gained for studies of: (i) in-vessel corium coolability - development of the methodologies to assess the efficiency of the control rod guide tube (CRGT) cooling as a potential SAM measure; (ii) debris bed coolability - characterization of the effective particle diameter of multi-size particles and qualification of friction law for two-phase flow in the beds packed with multi-size particles; and (iii) steam explosion - investigation of the effect of binary oxides mixtures properties on steam explosion. An approach for coupling of ECM/PECM models with RELAP5 was developed to enhance predictive fidelity for melt pool heat transfer. MELCOR was employed to examine the CRGT cooling efficiency by considering an entire accident scenario, and the simulation results show that the nominal flowrate (∼10kg/s) of CRGT cooling is sufficient to maintain the integrity of the vessel in a BWR of 3900 MWth, if the water injection is activated no later than 1 hour after scram. The POMECO-FL experimental data suggest that for a particulate bed packed with multi-size particles, the effective particle diameter can be represented by the area mean diameter of the particles, while at high velocity (Re>7) the effective particle diameter is closer to the length mean diameter. The pressure drop of two-phase flow through the particulate bed can be predicted by Reed's model. The steam explosion experiments performed at high melt superheat (>200oC) using oxidic mixture of WO3-CaO didn't detect an apparent difference in steam explosion energetics and preconditioning between the eutectic and noneutectic melts. This points out that the next step of MISTEE experiment will be conducted at lower superheat. (author)

  7. The present status of scientific applications of nuclear explosions

    Energy Technology Data Exchange (ETDEWEB)

    Cowan, G A; Diven, B C [Los Alamos Scientific Laboratory, University of California, Los Alamos, NM (United States)

    1970-05-15

    This is the fourth in a series of symposia which started, in 1957 at Livermore with the purpose of examining the peaceful uses of nuclear explosives. Although principal emphasis has {sup b}een placed on technological applications, the discussions have, from the outset, included the fascinating question of scientific uses. Of the possible scientific applications which were mentioned at the 1957 meeting, the proposals which attracted most attention involved uses of nuclear explosions for research in seismology. It is interesting to note that since then a very large and stimulating body of data in the field of seismology has been collected from nuclear tests. Ideas for scientific applications of nuclear explosions go back considerably further than 1957. During the war days Otto Frisch at Los Alamos suggested that a fission bomb would provide an excellent source of fast neutrons which could be led down a vacuum pipe and used for experiments in a relatively unscattered state. This idea, reinvented, modified, and elaborated upon in the ensuing twenty-five years, provides the basis for much of the research discussed in this morning's program. In 1952 a somewhat different property of nuclear explosions, their ability to produce intense neutron exposures on internal targets and to synthesize large quantities of multiple neutron capture products, was dramatically brought to our attention by analysis of debris from the first large thermonuclear explosion (Mike) in which the elements einsteinium and fermiun were observed for the first time. The reports of the next two Plowshare symposia in 1959 and 1964 help record the fascinating development of the scientific uses of neutrons in nuclear explosions. Starting with two 'wheel' experiments in 1958 to measure symmetry of fission in 235-U resonances, the use of external beams of energy-resolved neutrons was expanded on the 'Gnome' experiment in 1961 to include the measurement of neutron capture excitation functions for 238-U, 232

  8. Glass produced by underground nuclear explosions

    International Nuclear Information System (INIS)

    Schwartz, L.; Piwinskii, A.; Ryerson, F.; Tewes, H.; Beiriger, W.

    1983-01-01

    Detonation of an underground nuclear explosive produces a strong shock wave which propagates spherically outward, vaporizing the explosive and nearby rock and melting, the surrounding rock. The vaporized material expands adiabatically, forming a cavity. As the energy is dissipated during the cavity formation process, the explosive and rock debris condense and mix with the melted rock. The melt flows to the bottom of the cavity where it is quenched by fractured rock fragments falling from above as the cavity collapses. Measurements indicate that about 740 tonnes of rock and/or soil are melted for every kiloton (10 12 calories) of explosive energy, or about 25% of the explosive energy goes to melting rock. The resulting glass composition reflects the composition of the unaltered rock with explosive debris. The appearance ranges from white pumice to dense, dark lava. The bulk composition and color vary with the amount of explosive iron incorporated into the glass. The refractory explosion products are mixed with the solidified melt, although the degree of mixing is variable. Electron microprobe studies of glasses produced by Rainier in welded tuff have produced the following results: glasses are dehydrated relative to the host media, glasses are extremely heterogeneous on a 20 μm scale, a ubiquitous feature is the presence of dark marble-cake regions in the glass, which were locally enriched in iron and may be related to the debris, optically amorphous regions provide evidence of shock melting, only limited major element redistribution and homogenization occur within the cavity

  9. Delayed signatures of underground nuclear explosions

    Science.gov (United States)

    Carrigan, Charles R.; Sun, Yunwei; Hunter, Steven L.; Ruddle, David G.; Wagoner, Jeffrey L.; Myers, Katherine B. L.; Emer, Dudley F.; Drellack, Sigmund L.; Chipman, Veraun D.

    2016-03-01

    Radionuclide signals from underground nuclear explosions (UNEs) are strongly influenced by the surrounding hydrogeologic regime. One effect of containment is delay of detonation-produced radioxenon reaching the surface as well as lengthening of its period of detectability compared to uncontained explosions. Using a field-scale tracer experiment, we evaluate important transport properties of a former UNE site. We observe the character of signals at the surface due to the migration of gases from the post-detonation chimney under realistic transport conditions. Background radon signals are found to be highly responsive to cavity pressurization suggesting that large local radon anomalies may be an indicator of a clandestine UNE. Computer simulations, using transport properties obtained from the experiment, track radioxenon isotopes in the chimney and their migration to the surface. They show that the chimney surrounded by a fractured containment regime behaves as a leaky chemical reactor regarding its effect on isotopic evolution introducing a dependence on nuclear yield not previously considered. This evolutionary model for radioxenon isotopes is validated by atmospheric observations of radioxenon from a 2013 UNE in the Democratic People’s Republic of Korea (DPRK). Our model produces results similar to isotopic observations with nuclear yields being comparable to seismic estimates.

  10. Multistage reaction pathways in detonating high explosives

    International Nuclear Information System (INIS)

    Li, Ying; Kalia, Rajiv K.; Nakano, Aiichiro; Nomura, Ken-ichi; Vashishta, Priya

    2014-01-01

    Atomistic mechanisms underlying the reaction time and intermediate reaction products of detonating high explosives far from equilibrium have been elusive. This is because detonation is one of the hardest multiscale physics problems, in which diverse length and time scales play important roles. Here, large spatiotemporal-scale reactive molecular dynamics simulations validated by quantum molecular dynamics simulations reveal a two-stage reaction mechanism during the detonation of cyclotrimethylenetrinitramine crystal. Rapid production of N 2 and H 2 O within ∼10 ps is followed by delayed production of CO molecules beyond ns. We found that further decomposition towards the final products is inhibited by the formation of large metastable carbon- and oxygen-rich clusters with fractal geometry. In addition, we found distinct unimolecular and intermolecular reaction pathways, respectively, for the rapid N 2 and H 2 O productions

  11. Multistage reaction pathways in detonating high explosives

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ying [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States); Argonne Leadership Computing Facility, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Kalia, Rajiv K.; Nakano, Aiichiro; Nomura, Ken-ichi; Vashishta, Priya [Collaboratory for Advanced Computing and Simulations, Department of Physics and Astronomy, Department of Computer Science, and Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089-0242 (United States)

    2014-11-17

    Atomistic mechanisms underlying the reaction time and intermediate reaction products of detonating high explosives far from equilibrium have been elusive. This is because detonation is one of the hardest multiscale physics problems, in which diverse length and time scales play important roles. Here, large spatiotemporal-scale reactive molecular dynamics simulations validated by quantum molecular dynamics simulations reveal a two-stage reaction mechanism during the detonation of cyclotrimethylenetrinitramine crystal. Rapid production of N{sub 2} and H{sub 2}O within ∼10 ps is followed by delayed production of CO molecules beyond ns. We found that further decomposition towards the final products is inhibited by the formation of large metastable carbon- and oxygen-rich clusters with fractal geometry. In addition, we found distinct unimolecular and intermolecular reaction pathways, respectively, for the rapid N{sub 2} and H{sub 2}O productions.

  12. The Pore Collapse “Hot-Spots” Model Coupled with Brittle Damage for Solid Explosives

    Directory of Open Access Journals (Sweden)

    L. R. Cheng

    2014-01-01

    Full Text Available This paper is devoted to the building of a numerical pore collapse model with “hot-spots” formation for the impacted damage explosives. According to damage mechanical evolution of brittle material, the one-dimensional elastic-viscoplastic collapse model was improved to incorporate the impact damage during the dynamic collapse of pores. The damage of explosives was studied using the statistical crack mechanics (SCRAM. The effects of the heat conduction and the chemical reaction were taken into account in the formation of “hot-spots.” To verify the improved model, numerical simulations were carried out for different pressure states and used to model a multiple-impact experiment. The results show that repeated weak impacts can lead to the collapse of pores and the “hot-spots” may occur due to the accumulation of internal defects accompanied by the softening of explosives.

  13. Reduction methods and uncertainty analysis: application to a Chemistry-Transport Model for modeling and simulation of impacts

    International Nuclear Information System (INIS)

    Boutahar, Jaouad

    2004-01-01

    In an integrated impact assessment, one has to test several scenarios of the model inputs or/and to identify the effects of model input uncertainties on the model outputs. In both cases, a large number of simulations of the model is necessary. That of course is not feasible with comprehensive Chemistry-Transport Model, due to the need for huge CPU times. Two approaches may be used in order to circumvent these difficulties: The first approach consists in reducing the computational cost of the original model by building a reduced model. Two reduction techniques are used: the first method, POD, is related to the statistical behaviour of the system and is based on a proper orthogonal decomposition of the solutions. The second method, is an efficient representation of the input/output behaviour through look-up tables. It describes the output model as an expansion of finite hierarchical correlated function in terms of the input variables. The second approach is based on reducing the number of models runs required by the standard Monte Carlo methods. It characterizes the probabilistic response of the uncertain model output as an expansion of orthogonal polynomials according to model inputs uncertainties. Then the classical Monte Carlo simulation can easily be used to compute the probability density of the uncertain output. Another key point in an integrated impact assessment is to develop strategies for the reduction of emissions by computing Source/Receptor matrices for several years of simulations. We proposed here an efficient method to calculate these matrices by using the adjoint model and in particular by defining the 'representative chemical day'. All of these methods are applied to POLAIR3D, a Chemistry-Transport model developed in this thesis. (author) [fr

  14. The CREST reactive-burn model for explosives

    Directory of Open Access Journals (Sweden)

    Maheswaran M-A.

    2011-01-01

    Full Text Available CREST is an innovative reactive-burn model that has been developed at AWE for simulating shock initiation and detonation propagation behaviour in explosives. The model has a different basis from other reactive-burn models in that its reaction rate is independent of local flow variables behind the shock wave e.g. pressure and temperature. The foundation for CREST, based on a detailed analysis of data from particle-velocity gauge experiments, is that the reaction rate depends only on the local shock strength and the time since the shock passed. Since a measure of shock strength is the entropy of the non-reacted explosive, which remains constant behind a shock, CREST uses an entropy-dependent reaction rate. This paper will provide an overview of the CREST model and its predictive capability. In particular, it will be shown that the model can predict a wide range of experimental phenomena for both shock initiation (e.g. the effects of porosity and initial temperature on sustained-shock and thin-flyer initiation and detonation propagation (e.g. the diameter effect curve and detonation failure cones using a single set of coefficients.

  15. Nano-powder production by electrical explosion of wires

    International Nuclear Information System (INIS)

    Mao Zhiguo; Zou Xiaobing; Wang Xinxin; Jiang Weihua

    2010-01-01

    A device for nano-powder production by electrical explosion of wires was designed and built. Eight wires housed in the discharge chamber are exploded one by one before opening the chamber for the collection of the produced nano-powder. To increase the rate of energy deposition into a wire, the electrical behavior of the discharge circuit including the exploding wire was simulated. The results showed that both reducing the circuit inductance and reducing the capacitance of the energy-storage capacitor (keeping the storage energy constant) can increase the energy deposition rate. To better understand the physical processes of the nano-powder formation by the wire vapor, a Mach-Zehnder interferometer was used to record the time evolution of the wire vapor as well as the plasma. A thermal expansion lag of the dense vapor core as well as more than one times of the vapor burst was observed for the first time. Finally, nano-powders of titanium nitride, titanium dioxide, copper oxides and zinc oxide were produced by electrical explosion of wires. (authors)

  16. Study on explosives and their quality performance

    Energy Technology Data Exchange (ETDEWEB)

    Nabiullah, M.; Pingua, B.M.P.; Jagdish Khan, M.; Emranuzzaman [Central Mining Research Institute, Dhanbad (India)

    2005-07-01

    There are about forty suppliers of explosive and blasting accessories in India manufacturing site mixed emulsion, site mixed slurry, ANFO, HANFO, packed products, and blasting accessories of use in surface and underground mines. A field laboratory was set up to measure explosive properties of explosive samples, cast booster, detonating fuse, detonators, cord relay, MS connector, and shock tubes. Density, velocity of detonation, water percentage, water resistance, and energy output were considered as the important properties of explosives. A rating system was designed for selection of good explosive products. The delay interval and delay scattering in cord relay and shock tube was studied to improve blast performance. This paper describes in detail the method of measurement and vender rating system for explosive products as per marking system accepted by Coal India. 12 refs., 4 figs., 22 tabs.

  17. Mid-IR DIAL for high-resolution mapping of explosive precursors

    Science.gov (United States)

    Mitev, V.; Babichenko, S.; Bennes, J.; Borelli, R.; Dolfi-Bouteyre, A.; Fiorani, L.; Hespel, L.; Huet, T.; Palucci, A.; Pistilli, M.; Puiu, A.; Rebane, O.; Sobolev, I.

    2013-10-01

    A DIAL instrument on a moving platform is seen as a valuable remote sensing component in a sensor network for area monitoring, targeting sites involved in unauthorised explosive manufacturing. Such instrument will perform the area mapping of the vapour concentration of key substances, known to be used as precursors in explosive fabrication, such as acetone and nitromethane. The IR spectra of acetone and nitromethane vapours have been defined from available spectroscopy databases and from laboratory measurements as showing optimal spectral band for the DIAL operation in the spectral range of 3.0 μm - 3.5 μm. The DIAL operation has been numerically simulated, with inputs based on the HITRAN database, the U.S. Standard Atmosphere and aerosol simulation software package OPAC. A combination of OPO and OPA has been chosen as a transmitter, where the idler wavelength is used for probing, with wavelength tuning in sequence. A scanner mounted on top of the coaxially aligned laser and receiver, is capable of covering almost 360 degrees horizontally and +/-30 degrees vertically. The detection is performed by a photovoltaic photodiode with 4-stage cooling, with a signal digitalisation having 14 bit amplitude resolution and 125 Ms/s sampling rate. Here we present the development and the first test of the DIAL instrument.

  18. Screening sealed bottles for liquid explosives

    Science.gov (United States)

    Kumar, Sankaran; McMichael, W. Casey; Kim, Y.-W.; Sheldon, Alan G.; Magnuson, Erik E.; Ficke, L.; Chhoa, T. K.; Moeller, C. R.; Barrall, Geoffrey A.; Burnett, Lowell J.; Czipott, Peter V.; Pence, J. S.; Skvoretz, David C.

    1997-01-01

    A particularly disturbing development affecting transportation safety and security is the increasing use of terrorist devices which avoid detection by conventional means through the use of liquid explosives and flammables. The hazardous materials are generally hidden in wine or liquor bottles that cannot be opened routinely for inspection. This problem was highlighted by the liquid explosives threat which disrupted air traffic between the US an the Far East for an extended period in 1995. Quantum Magnetics has developed a Liquid Explosives Screening systems capable of scanning unopened bottles for liquid explosives. The system can be operated to detect specific explosives directly or to verify the labeled or bar-coded contents of the container. In this system, magnetic resonance (MR) is used to interrogate the liquid. MR produces an extremely rich data set and many characteristics of the MR response can be determined simultaneously. As a result, multiple MR signatures can be defined for any given set of liquids, and the signature complexity then selected according to the level of threat. The Quantum Magnetics Liquid Explosives Screening System is currently operational. Following extensive laboratory testing, a field trial of the system was carried out at the Los Angeles International Airport.

  19. Hydrodynamics of Explosion Experiments and Models

    CERN Document Server

    Kedrinskii, Valery K

    2005-01-01

    Hydronamics of Explosion presents the research results for the problems of underwater explosions and contains a detailed analysis of the structure and the parameters of the wave fields generated by explosions of cord and spiral charges, a description of the formation mechanisms for a wide range of cumulative flows at underwater explosions near the free surface, and the relevant mathematical models. Shock-wave transformation in bubbly liquids, shock-wave amplification due to collision and focusing, and the formation of bubble detonation waves in reactive bubbly liquids are studied in detail. Particular emphasis is placed on the investigation of wave processes in cavitating liquids, which incorporates the concepts of the strength of real liquids containing natural microinhomogeneities, the relaxation of tensile stress, and the cavitation fracture of a liquid as the inversion of its two-phase state under impulsive (explosive) loading. The problems are classed among essentially nonlinear processes that occur unde...

  20. Gas induced fire and explosion frequencies

    International Nuclear Information System (INIS)

    Coutts, D.A.

    1997-01-01

    The use and handling of flammable gases poses a fire and explosion hazard to many DOE nuclear facilities. This hazard is not unique to DOE facilities. Each year over 2,900 non-residential structural fires occur in the U.S. where a gas is the first item ignited. Details from these events are collected by the National Fire Incident Reporting System (NFIRS) through an extensive reporting network. This extensive data set (800,000 fires in non-residential structures over a 5-year period) is an underutilized resource within the DOE community. Explosions in nuclear facilities can have very severe consequences. The explosion can both damage the facility containment and provide a mechanism for significant radiological dispersion. In addition, an explosion can have significant worker safety implications. Because of this a quantitative frequency estimate for explosions in an SRS laboratory facility has been prepared using the NFIRS data. 6 refs., 1 tab

  1. The MARS simulation of the nuclear weapons preparedness LOTTA scenario

    International Nuclear Information System (INIS)

    Tovedal, H.

    2001-03-01

    The simulation method MARS, Mathematical Radiac Simulation, is primarily intended for preparedness exercises in nuclear fallout areas and simulates the ionizing radiation dose rates from fission products deposited on the ground, i.e. fallout from a nuclear weapons explosion or from a release of radioactive material from a nuclear reactor. MARS gives at any time after the fictitious explosion or reactor release the dose rates at any position in the fallout area. MARS has been used for simulation of an exercise scenario called LOTTA, designed for training and test of a radiac preparedness group in the Dept. of Nuclear Protection at FOI. The group is a member of a national preparedness organisation under the Swedish Radiation Protection Institute, SSI. This MARS application was a simulation of the entire course of events following a fictitious nuclear weapons explosion, including the fission product deposition process and the ultimate activity and dose rate distribution in the fallout area. The simulation was based on deposition and fallout prognoses worked out by FOI, using the prognosis model PELLO. This report presents a short description of the simulation of the LOTTA scenario. A more detailed presentation of the general MARS method can be found in the report 'Mathematical Radiac Simulation, MARS'

  2. Safety problems with abandoned explosive facilities

    International Nuclear Information System (INIS)

    Courtright, W.C.

    1969-01-01

    Procedures were developed for the safe removal of explosive and radioactive contaminated materials structures and drains from abandoned sites, including explosives processing and service buildings with a goal to return the entire area to its natural state and to permit public access. The safety problems encountered in the cleanup and their solutions are applicable to modification and maintenance work in operating explosive facilities. (U.S.)

  3. HERMES: A Model to Describe Deformation, Burning, Explosion, and Detonation

    Energy Technology Data Exchange (ETDEWEB)

    Reaugh, J E

    2011-11-22

    HERMES (High Explosive Response to MEchanical Stimulus) was developed to fill the need for a model to describe an explosive response of the type described as BVR (Burn to Violent Response) or HEVR (High Explosive Violent Response). Characteristically this response leaves a substantial amount of explosive unconsumed, the time to reaction is long, and the peak pressure developed is low. In contrast, detonations characteristically consume all explosive present, the time to reaction is short, and peak pressures are high. However, most of the previous models to describe explosive response were models for detonation. The earliest models to describe the response of explosives to mechanical stimulus in computer simulations were applied to intentional detonation (performance) of nearly ideal explosives. In this case, an ideal explosive is one with a vanishingly small reaction zone. A detonation is supersonic with respect to the undetonated explosive (reactant). The reactant cannot respond to the pressure of the detonation before the detonation front arrives, so the precise compressibility of the reactant does not matter. Further, the mesh sizes that were practical for the computer resources then available were large with respect to the reaction zone. As a result, methods then used to model detonations, known as {beta}-burn or program burn, were not intended to resolve the structure of the reaction zone. Instead, these methods spread the detonation front over a few finite-difference zones, in the same spirit that artificial viscosity is used to spread the shock front in inert materials over a few finite-difference zones. These methods are still widely used when the structure of the reaction zone and the build-up to detonation are unimportant. Later detonation models resolved the reaction zone. These models were applied both to performance, particularly as it is affected by the size of the charge, and to situations in which the stimulus was less than that needed for reliable

  4. Modeling solid thermal explosion containment on reactor HNIW and HMX

    International Nuclear Information System (INIS)

    Lin, Chun-Ping; Chang, Chang-Ping; Chou, Yu-Chuan; Chu, Yung-Chuan; Shu, Chi-Min

    2010-01-01

    2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaaza-isowurtzitane (HNIW), also known as CL-20 and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), are highly energetic materials which have been popular in national defense industries for years. This study established the models of thermal decomposition and thermal explosion hazard for HNIW and HMX. Differential scanning calorimetry (DSC) data were used for parameters determination of the thermokinetic models, and then these models were employed for simulation of thermal explosion in a 437 L barrel reactor and a 24 kg cubic box package. Experimental results indicating the best storage conditions to avoid any violent runaway reaction of HNIW and HMX were also discovered. This study also developed an efficient procedure regarding creation of thermokinetics and assessment of thermal hazards of HNIW and HMX that could be applied to ensure safe storage conditions.

  5. The coupled chemistry-climate model LMDz-REPROBUS: description and evaluation of a transient simulation of the period 1980–1999

    Directory of Open Access Journals (Sweden)

    L. Jourdain

    2008-06-01

    Full Text Available We present a description and evaluation of the Chemistry-Climate Model (CCM LMDz-REPROBUS, which couples interactively the extended version of the Laboratoire de Météorologie Dynamique General Circulation Model (LMDz GCM and the stratospheric chemistry module of the REactive Processes Ruling the Ozone BUdget in the Stratosphere (REPROBUS model. The transient simulation evaluated here covers the period 1980–1999. The introduction of an interactive stratospheric chemistry module improves the model dynamical climatology, with a substantial reduction of the temperature biases in the lower tropical stratosphere. However, at high latitudes in the Southern Hemisphere, a negative temperature bias, that is already present in the GCM version, albeit with a smaller magnitude, leads to an overestimation of the ozone depletion and its vertical extent in the CCM. This in turn contributes to maintain low polar temperatures in the vortex, delay the break-up of the vortex and the recovery of polar ozone. The latitudinal and vertical variation of the mean age of air compares favourable with estimates derived from long-lived species measurements, though the model mean age of air is 1–3 years too young in the middle stratosphere. The model also reproduces the observed "tape recorder" in tropical total hydrogen (=H2O+2×CH4, but its propagation is about 30% too fast and its signal fades away slightly too quickly. The analysis of the global distributions of CH4 and N2O suggests that the subtropical transport barriers are correctly represented in the simulation. LMDz-REPROBUS also reproduces fairly well most of the spatial and seasonal variations of the stratospheric chemical species, in particular ozone. However, because of the Antarctic cold bias, large discrepancies are found for most species at high latitudes in the Southern Hemisphere during the spring and early summer. In the Northern Hemisphere, polar ozone depletion and its variability are underestimated

  6. Steam explosions in sodium cooled breeder reactors

    International Nuclear Information System (INIS)

    Lundell, B.

    1982-01-01

    Steam explosion is considered a physical process which transport heat from molten fuel to liquid coolant so fast that the coolant starts boiling in an explosion-like manner. The arising pressure waves transform part of the thermal energy to mechanical energy. This can stress the reactor tank and threaten its hightness. The course of the explosion has not been theoretical explained. Experimental results indicate that the probability of steam explosions in a breeder reactor is small. The efficiency of the transformation of the heat of fusion into mechanical energy in substantially lower than the theoretical maximum value. The mechanical stress from the steam explosion on the reactor tank does not seem to jeopardize its tightness. (G.B.)

  7. Hydrocarbon production with nuclear explosives

    International Nuclear Information System (INIS)

    Wade Watkins, J.

    1970-01-01

    The tremendous energy of nuclear explosives and the small dimensions of the explosive package make an ideal combination for drill-hole explosive emplacement in deep, thick hydrocarbon deposits. Potential applications exist in fracturing low permeability natural-gas and petroleum formations for stimulating production, fracturing oil shale to permit in situ retorting, and creating storage chimneys for natural gas, liquefied petroleum gas, petroleum, petroleum products, helium, and other fluids. Calculations show, for example, that less than 100 shots per year would be needed to stabilize the natural gas reserves to production ratio. Under the Government-industry Plowshare program, two experiments, Projects Gasbuggy and Rulison, were conducted to stimulate natural gas production from low-permeability formations. Incomplete information indicates that both were technically successful. Potential problems associated with the use of nuclear explosives for underground engineering applications are radioactive contamination, maximum yield limitations, high costs of detonating contained nuclear explosives, and adverse public opinion. Results at Project Gasbuggy and other considerations indicated that the problem of radioactive contamination was about as predicted and not an insurmountable one. Also, it was demonstrated that shots at adequate depths could be detonated without appreciable damage to existing surface and subsurface buildings, natural features, and equipment. However, costs must be reduced and the public must be better informed before these techniques can be widely used in field operations. On the basis of present knowledge, the potential of nuclear-explosive stimulation of hydrocarbon production appears good. Additional field experiments will be required to adequately explore that potential. (author)

  8. Hydrocarbon production with nuclear explosives

    Energy Technology Data Exchange (ETDEWEB)

    Wade Watkins, J [Petroleum Research, Bureau of Mines, U.S. Department of the Interior, Washington, DC (United States)

    1970-05-01

    The tremendous energy of nuclear explosives and the small dimensions of the explosive package make an ideal combination for drill-hole explosive emplacement in deep, thick hydrocarbon deposits. Potential applications exist in fracturing low permeability natural-gas and petroleum formations for stimulating production, fracturing oil shale to permit in situ retorting, and creating storage chimneys for natural gas, liquefied petroleum gas, petroleum, petroleum products, helium, and other fluids. Calculations show, for example, that less than 100 shots per year would be needed to stabilize the natural gas reserves to production ratio. Under the Government-industry Plowshare program, two experiments, Projects Gasbuggy and Rulison, were conducted to stimulate natural gas production from low-permeability formations. Incomplete information indicates that both were technically successful. Potential problems associated with the use of nuclear explosives for underground engineering applications are radioactive contamination, maximum yield limitations, high costs of detonating contained nuclear explosives, and adverse public opinion. Results at Project Gasbuggy and other considerations indicated that the problem of radioactive contamination was about as predicted and not an insurmountable one. Also, it was demonstrated that shots at adequate depths could be detonated without appreciable damage to existing surface and subsurface buildings, natural features, and equipment. However, costs must be reduced and the public must be better informed before these techniques can be widely used in field operations. On the basis of present knowledge, the potential of nuclear-explosive stimulation of hydrocarbon production appears good. Additional field experiments will be required to adequately explore that potential. (author)

  9. Chemistry Simulations Using MERRA-2 Reanalysis with the GMI CTM and Replay in Support of the Atmospheric Composition Community

    Science.gov (United States)

    Oman, Luke D.; Strahan, Susan E.

    2016-01-01

    Simulations using reanalyzed meteorological conditions have been long used to understand causes of atmospheric composition change over the recent past. Using the new Modern-Era Retrospective analysis for Research and Applications, version 2 (MERRA-2) meteorology, chemistry simulations are being conducted to create products covering 1980-2016 for the atmospheric composition community. These simulations use the Global Modeling Initiative (GMI) chemical mechanism in two different models: the GMI Chemical Transport Model (CTM) and the GEOS-5 model developed Replay mode. Replay mode means an integration of the GEOS-5 general circulation model that is incrementally adjusted each time step toward the MERRA-2 analysis. The GMI CTM is a 1 x 1.25 simulation and the MERRA-2 GMI Replay simulation uses the native MERRA-2 approximately horizontal resolution on the cubed sphere. The Replay simulations is driven by the online use of key MERRA-2 meteorological variables (i.e. U, V, T, and surface pressure) with all other variables calculated in response to those variables. A specialized set of transport diagnostics is included in both runs to better understand trace gas transport and changes over the recent past.

  10. A method for the direct numerical simulation of hypersonic boundary-layer instability with finite-rate chemistry

    International Nuclear Information System (INIS)

    Marxen, Olaf; Magin, Thierry E.; Shaqfeh, Eric S.G.; Iaccarino, Gianluca

    2013-01-01

    A new numerical method is presented here that allows to consider chemically reacting gases during the direct numerical simulation of a hypersonic fluid flow. The method comprises the direct coupling of a solver for the fluid mechanical model and a library providing the physio-chemical model. The numerical method for the fluid mechanical model integrates the compressible Navier–Stokes equations using an explicit time advancement scheme and high-order finite differences. This Navier–Stokes code can be applied to the investigation of laminar-turbulent transition and boundary-layer instability. The numerical method for the physio-chemical model provides thermodynamic and transport properties for different gases as well as chemical production rates, while here we exclusively consider a five species air mixture. The new method is verified for a number of test cases at Mach 10, including the one-dimensional high-temperature flow downstream of a normal shock, a hypersonic chemical reacting boundary layer in local thermodynamic equilibrium and a hypersonic reacting boundary layer with finite-rate chemistry. We are able to confirm that the diffusion flux plays an important role for a high-temperature boundary layer in local thermodynamic equilibrium. Moreover, we demonstrate that the flow for a case previously considered as a benchmark for the investigation of non-equilibrium chemistry can be regarded as frozen. Finally, the new method is applied to investigate the effect of finite-rate chemistry on boundary layer instability by considering the downstream evolution of a small-amplitude wave and comparing results with those obtained for a frozen gas as well as a gas in local thermodynamic equilibrium

  11. Radon, water chemistry and pollution check by volatile organic compounds in springs around Popocatepetl volcano, Mexico

    OpenAIRE

    M. Mena; G. Cisniega; B. Lopez; M. A. Armienta; C. Valdés; P. Peña; N. Segovia

    2005-01-01

    Popocatepetl volcano is a high-risk active volcano in Central Mexico where the highest population density in the country is settled. Radon in the soil and groundwater together with water chemistry from samples of nearby springs were analysed as a function of the 2002-2003 volcanic activity. The measurements of soil radon indicated fluctuations related to both the meteorological and sporadic explosive events. Groundwater radon showed essential differences in concentration d...

  12. High-explosive driven crowbar switch

    International Nuclear Information System (INIS)

    Dike, R.S.; Kewish, R.W. Jr.

    1976-01-01

    The disclosure relates to a compact explosive driven switch for use as a low resistance, low inductance crowbar switch. A high-explosive charge extrudes a deformable conductive metallic plate through a polyethylene insulating layer to achieve a hard current contact with a supportive annular conductor

  13. Introduction to High Explosives Science

    Energy Technology Data Exchange (ETDEWEB)

    Skidmore, Cary Bradford [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Preston, Daniel N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-11-17

    These are a set of slides for educational outreach to children on high explosives science. It gives an introduction to the elements involved in this science: carbon, hydrogen, nitrogen, and oxygen. Combined, these form the molecule HMX. Many pictures are also included to illustrate explosions.

  14. Donor free radical explosive composition

    Science.gov (United States)

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

    1980-04-01

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

  15. Peaceful applications of nuclear explosions

    International Nuclear Information System (INIS)

    Wallin, L.B.

    1975-12-01

    The intension of this report is to give a survey of the field of peaceful applications of nuclear explosions. As an introduction some examples of possibilities of application are given together with a simple description of nuclear explosions under ground. After a summary of what has been done and will be done in this field nationally and internationally, a short discussion of advantages and problems with peaceful application of nuclear explosions follows. The risks of spreading nuclear weapons due to this applications are also touched before the report is finished with an attempt to judge the future development in this field. (M.S.)

  16. Novel high explosive compositions

    Science.gov (United States)

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

    1968-04-16

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

  17. Damage of reactor buildings occurred at the Fukushima Daiichi accident. Focusing on sequence leading to hydrogen explosions

    International Nuclear Information System (INIS)

    Naito, Masanori

    2011-01-01

    Fukushima Daiichi accident discharged enormous radioactive materials confined inside into the environment due to hydrogen explosions occurred at reactor buildings and forced many people to live the refugee life. This article described overview of Great East Japan Earthquake, specifications of Fukushima Daiichi nuclear power plants, sequence of plant status after earthquake occurrence and computerized simulation of plant behavior of Unit 1 leading to core melt and hydrogen explosion. Simulation results with estimated and assumed conditions showed water level decreased to bottom of reactor core after 4 hrs and 15 minutes passed, core melt started after 6 hrs and 49 minutes passed, failure of core support plate after 7 hrs and 18 minutes passed and through failure of penetration at bottom of pressure vessel after 7 hrs and 25 minutes passed. Hydrogen concentration at operating floor of reactor building of Unit 1 would be 15% accumulated and the pressure would amount to about 5 bars after hydrogen explosion if reactor building did not rupture with leak-tight structure. Since reactor building was not pressure-proof structure, walls of operating floor would rupture before 5 bars attained. (T. Tanaka)

  18. EXPLOSIVE NUCLEOSYNTHESIS IN THE NEUTRINO-DRIVEN ASPHERICAL SUPERNOVA EXPLOSION OF A NON-ROTATING 15 Msun STAR WITH SOLAR METALLICITY

    International Nuclear Information System (INIS)

    Fujimoto, Shin-ichiro; Kotake, Kei; Hashimoto, Masa-aki; Ono, Masaomi; Ohnishi, Naofumi

    2011-01-01

    We investigate explosive nucleosynthesis in a non-rotating 15 M sun star with solar metallicity that explodes by a neutrino-heating supernova (SN) mechanism aided by both standing accretion shock instability (SASI) and convection. To trigger explosions in our two-dimensional hydrodynamic simulations, we approximate the neutrino transport with a simple light-bulb scheme and systematically change the neutrino fluxes emitted from the protoneutron star. By a post-processing calculation, we evaluate abundances and masses of the SN ejecta for nuclei with a mass number ≤70, employing a large nuclear reaction network. Aspherical abundance distributions, which are observed in nearby core-collapse SN remnants, are obtained for the non-rotating spherically symmetric progenitor, due to the growth of a low-mode SASI. The abundance pattern of the SN ejecta is similar to that of the solar system for models whose masses range between (0.4-0.5) M sun of the ejecta from the inner region (≤10, 000 km) of the precollapse core. For the models, the explosion energies and the 56 Ni masses are ≅ 10 51 erg and (0.05-0.06) M sun , respectively; their estimated baryonic masses of the neutron star are comparable to the ones observed in neutron-star binaries. These findings may have little uncertainty because most of the ejecta is composed of matter that is heated via the shock wave and has relatively definite abundances. The abundance ratios for Ne, Mg, Si, and Fe observed in the Cygnus loop are reproduced well with the SN ejecta from an inner region of the 15 M sun progenitor.

  19. Explosion approach for external safety assessment: a case study

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D. Michael; Halford, Ann [Germanischer Lloyd, Loughborough (United Kingdom); Mendes, Renato F. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

    2009-07-01

    Several questions related to the potential for explosions are explored as this became an important subject during an enterprise risk analysis. The understanding of explosions underwent a substantial evolution in the final 20 years of the 20{sup th} century following international research projects in Europe involving several research institutes, as well gas and oil companies. This led to the development of techniques that could be used to assess the potential consequences of explosions on oil, gas and petrochemical facilities. This paper presents an overview of the potential for explosions in communities close to industrial sites or pipelines right of way (RoW), where the standard explosion assessment methods cannot be applied. With reference to experimental studies, the potential for confined explosions in buildings and Vapor Cloud Explosions is explored. Vapor Cloud Explosion incidents in rural or urban areas are also discussed. The method used for incorporating possible explosion and fire events in risk studies is also described using a case study. Standard explosion assessment methodologies and a revised approach are compared as part of an on going evaluation of risk (author)

  20. Risk Quantitative Determination of Fire and Explosion in a Process Unit By Dow’s Fire and Explosion Index

    Directory of Open Access Journals (Sweden)

    S. Varmazyar

    2008-04-01

    Full Text Available Background and aims   Fire and explosion hazards are the first and second of major hazards in process industries, respectively. This study has been done to determine fire and explosion risk severity,radius of exposure and estimating of most probable loss.   Methods   In this quantitative study process unit has been selected with affecting parameters on  fire and explosion risk. Then, it was analyzed by DOW's fire and explosion index (F&EI. Technical data were obtained from process documents and reports, fire and explosion guideline.After calculating of DOW's index, radius of exposure determined and finally most  probable loss was estimated.   Results   The results showed an F&EI value of 226 for this process unit.The F&EI was extremely  high and unacceptable.Risk severity was categorized in sever class.Radius of exposure and damage factor were calculated 57 meters and 83%,respectively. As well as most probable loss was  estimated about 6.7 million dollars.   Conclusion   F&EI is a proper technique for risk assessment and loss estimation of fire and  explosion in process industries.Also,It is an important index for detecting high risk and low risk   areas in an industry. At this technique, all of factors affecting on fire and explosion risk was  showed as index that is a base for judgement risk class. Finally, estimated losses could be used as  a base of fire and explosion insurance.

  1. THE PROGENITOR DEPENDENCE OF THE PRE-EXPLOSION NEUTRINO EMISSION IN CORE-COLLAPSE SUPERNOVAE

    International Nuclear Information System (INIS)

    O'Connor, Evan; Ott, Christian D.

    2013-01-01

    We perform spherically symmetric general-relativistic simulations of core collapse and the postbounce pre-explosion phase in 32 presupernova stellar models of solar metallicity with zero-age main-sequence masses of 12-120 M ☉ . Using energy-dependent three-species neutrino transport in the two-moment approximation with an analytic closure, we show that the emitted neutrino luminosities and spectra follow very systematic trends that are correlated with the compactness (∼M/R) of the progenitor star's inner regions via the accretion rate in the pre-explosion phase. We find that these qualitative trends depend only weakly on the nuclear equation of state (EOS), but quantitative observational statements will require independent constraints on the EOS and the rotation rate of the core as well as a more complete understanding of neutrino oscillations. We investigate the simulated response of water Cherenkov detectors to the electron antineutrino fluxes from our models and find that the large statistics of a galactic core collapse event may allow robust conclusions on the inner structure of the progenitor star.

  2. THE PROGENITOR DEPENDENCE OF THE PRE-EXPLOSION NEUTRINO EMISSION IN CORE-COLLAPSE SUPERNOVAE

    Energy Technology Data Exchange (ETDEWEB)

    O' Connor, Evan; Ott, Christian D., E-mail: evanoc@tapir.caltech.edu, E-mail: cott@tapir.caltech.edu [TAPIR, California Institute of Technology, Mailcode 350-17, Pasadena, CA 91125 (United States)

    2013-01-10

    We perform spherically symmetric general-relativistic simulations of core collapse and the postbounce pre-explosion phase in 32 presupernova stellar models of solar metallicity with zero-age main-sequence masses of 12-120 M {sub Sun }. Using energy-dependent three-species neutrino transport in the two-moment approximation with an analytic closure, we show that the emitted neutrino luminosities and spectra follow very systematic trends that are correlated with the compactness ({approx}M/R) of the progenitor star's inner regions via the accretion rate in the pre-explosion phase. We find that these qualitative trends depend only weakly on the nuclear equation of state (EOS), but quantitative observational statements will require independent constraints on the EOS and the rotation rate of the core as well as a more complete understanding of neutrino oscillations. We investigate the simulated response of water Cherenkov detectors to the electron antineutrino fluxes from our models and find that the large statistics of a galactic core collapse event may allow robust conclusions on the inner structure of the progenitor star.

  3. 27 CFR 555.63 - Explosives magazine changes.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2010-04-01 2010-04-01 false Explosives magazine... § 555.63 Explosives magazine changes. (a) General. (1) The requirements of this section are applicable to magazines used for other than temporary (under 24 hours) storage of explosives. (2) A magazine is...

  4. Explosive Leidenfrost droplets

    Science.gov (United States)

    Colinet, Pierre; Moreau, Florian; Dorbolo, Stéphane

    2017-11-01

    We show that Leidenfrost droplets made of an aqueous solution of surfactant undergo a violent explosion in a wide range of initial volumes and concentrations. This unexpected behavior turns out to be triggered by the formation of a gel-like shell, followed by a sharp temperature increase. Comparing a simple model of the radial surfactant distribution inside a spherical droplet with experiments allows highlighting the existence of a critical surface concentration for the shell to form. The temperature rise (attributed to boiling point elevation with surface concentration) is a key feature leading to the explosion, instead of the implosion (buckling) scenario reported by other authors. Indeed, under some conditions, this temperature increase is shown to be sufficient to trigger nucleation and growth of vapor bubbles in the highly superheated liquid bulk, stretching the surrounding elastic shell up to its rupture limit. The successive timescales characterizing this explosion sequence are also discussed. Funding sources: F.R.S. - FNRS (ODILE and DITRASOL projects, RD and SRA positions of P. Colinet and S. Dorbolo), BELSPO (IAP 7/38 MicroMAST project).

  5. Risk of dust explosions of combustible nanomaterials

    International Nuclear Information System (INIS)

    Dobashi, Ritsu

    2009-01-01

    Nanomaterials have several valuable properties and are widely used for various practical applications. However, safety matters are suspected such as the influence on health and environment, and fire and explosion hazards. To minimize the risk of nanomaterials, appropriate understanding of these hazards is indispensable. Nanoparticles of combustible materials have potential hazard of dust explosion accidents. However, the explosion risk of nanomaterials has not yet been understood adequately because of the lack of data for nanomaterials. In this presentation, the risk of dust explosions of nanomaterials is discussed.

  6. Gas-grain chemistry in cold interstellar cloud cores with a microscopic Monte Carlo approach to surface chemistry

    Science.gov (United States)

    Chang, Q.; Cuppen, H. M.; Herbst, E.

    2007-07-01

    Aims:We have recently developed a microscopic Monte Carlo approach to study surface chemistry on interstellar grains and the morphology of ice mantles. The method is designed to eliminate the problems inherent in the rate-equation formalism to surface chemistry. Here we report the first use of this method in a chemical model of cold interstellar cloud cores that includes both gas-phase and surface chemistry. The surface chemical network consists of a small number of diffusive reactions that can produce molecular oxygen, water, carbon dioxide, formaldehyde, methanol and assorted radicals. Methods: The simulation is started by running a gas-phase model including accretion onto grains but no surface chemistry or evaporation. The starting surface consists of either flat or rough olivine. We introduce the surface chemistry of the three species H, O and CO in an iterative manner using our stochastic technique. Under the conditions of the simulation, only atomic hydrogen can evaporate to a significant extent. Although it has little effect on other gas-phase species, the evaporation of atomic hydrogen changes its gas-phase abundance, which in turn changes the flux of atomic hydrogen onto grains. The effect on the surface chemistry is treated until convergence occurs. We neglect all non-thermal desorptive processes. Results: We determine the mantle abundances of assorted molecules as a function of time through 2 × 105 yr. Our method also allows determination of the abundance of each molecule in specific monolayers. The mantle results can be compared with observations of water, carbon dioxide, carbon monoxide, and methanol ices in the sources W33A and Elias 16. Other than a slight underproduction of mantle CO, our results are in very good agreement with observations.

  7. GEOS-5 Chemistry Transport Model User's Guide

    Science.gov (United States)

    Kouatchou, J.; Molod, A.; Nielsen, J. E.; Auer, B.; Putman, W.; Clune, T.

    2015-01-01

    The Goddard Earth Observing System version 5 (GEOS-5) General Circulation Model (GCM) makes use of the Earth System Modeling Framework (ESMF) to enable model configurations with many functions. One of the options of the GEOS-5 GCM is the GEOS-5 Chemistry Transport Model (GEOS-5 CTM), which is an offline simulation of chemistry and constituent transport driven by a specified meteorology and other model output fields. This document describes the basic components of the GEOS-5 CTM, and is a user's guide on to how to obtain and run simulations on the NCCS Discover platform. In addition, we provide information on how to change the model configuration input files to meet users' needs.

  8. Kiche: A simulation tool for kinetics of iodine chemistry in the containment of light water reactors under severe accident conditions (Contract research)

    International Nuclear Information System (INIS)

    Moriyama, Kiyofumi; Maruyama, Yu; Nakamura, Hideo

    2011-03-01

    An iodine chemistry simulation tool, Kiche, was developed for analyses of chemical kinetics relevant to iodine volatilization in the containment vessel of light water reactors (LWRs) during a severe accident. It consists of a Fortran code to solve chemical kinetics models, reaction databases written in plain text format, and peripheral tools to convert the reaction databases into Fortran codes to solve corresponding ordinary differential equation sets. Potential advantages of Kiche are the text format reaction database separated from the code that provides flexibility of the chemistry model, and, being a Fortran code which is relatively easily coupled with other Fortran codes such as severe accident analysis codes. This document describes the model, solution method, code structure, and examples of application of Kiche for simulation of experiments. The calculation results by the present model agreed well with the experimental data and it indicates the model properly includes the most important processes in the volatilization of iodine from irradiated iodide solutions with or without organic impurities. The appendixes give practical information for the usage of Kiche. (author)

  9. The Use of Online Modules and the Effect on Student Outcomes in a High School Chemistry Class

    Science.gov (United States)

    Lamb, Richard L.; Annetta, Len

    2013-10-01

    The purpose of the study was to review the efficacy of online chemistry simulations in a high school chemistry class and provide discussion of the factors that may affect student learning. The sample consisted of 351 high school students exposed to online simulations. Researchers administered a pretest, intermediate test and posttest to measure chemistry content knowledge acquired during the use of online chemistry laboratory simulations. The authors also analyzed student journal entries as an attitudinal measure of chemistry during the simulation experience. The four analyses conducted were Repeated Time Measures Analysis of Variance, a three-way Analysis of Variance, Logistic Regression and Multiple Analysis of Variance. Each of these analyses provides for a slightly different aspect of factors regarding student attitudes and outcomes. Results indicate that there is a statistically significant main effect across grouping type (experimental versus control, p = 0.042, α = 0.05). Analysis of student journal entries suggests that attitudinal factors may affect student outcomes concerning the use of online supplemental instruction. Implications for this study show that the use of online simulations promotes increased understanding of chemistry content through open-ended and interactive questioning.

  10. NCAW feed chemistry: Effect of starting chemistry on melter offgas and iron redox

    International Nuclear Information System (INIS)

    Smith, P.A.; Vienna, J.D.; Merz, M.D.

    1995-03-01

    The Pacific Northwest Laboratory (PNL) Vitrification Technology Development (PVTD) program has been established to develop technology to support immobilization of selected Hanford wastes. The effort of the PVTD program is directed by the U.S. Department of Energy (DOE). This report is part of the effort and focuses on the effect of starting waste chemistry on the vitrification process. The objective of the investigation was the evaluation of the effect of starting chemistry on the cold cap behavior in the vitrification of simulated neutralized current acid waste (NCAW). In addition this investigation provides an initial laboratory investigation of the cold cap and method for evaluation of alternate reductants

  11. Velocity Dispersion of Ionized Gas and Multiple Supernova Explosions

    Directory of Open Access Journals (Sweden)

    Vasiliev E. O.

    2015-06-01

    Full Text Available We use 3D numerical simulations to study the evolution of the Hα intensity and velocity dispersion for single and multiple supernova (SN explosions. We find that the IHα– σ diagram obtained for simulated gas flows is similar in shape to that observed in dwarf galaxies. We conclude that colliding SN shells with significant difference in age are responsible for high velocity dispersion that reaches up to ≳ 100 km s−1. Such a high velocity dispersion could be hardly obtained for a single SN remnant. Peaks of velocity dispersion in the IHα– σ diagram may correspond to several isolated or merged SN remnants with moderately different ages. Degrading the spatial resolution in the Hα intensity and velocity dispersion maps makes the simulated IHα– σ diagrams close to those observed in dwarf galaxies not only in shape, but also quantitatively.

  12. Load histories from steam explosions during core melt accidents

    International Nuclear Information System (INIS)

    Jacobs, H.; Kolev, N.I.

    1992-01-01

    For the analysis of steam explosions a multicomponent multiphase thermohydraulic code is required which describes at least the motions of melt, water, and steam by separate velocity fields. One example of these very rare codes is the IVA3 code the development of which was brought to an interim close in 1991. As an example of a typical application of this code, precalculations of the FARO LWR Scoping Test 2 performed at Ispra are discussed. Unfortunately, the calculation results cannot be compared directly to the test results because of important differences between planned and achieved test parameters. Above all, only about one third of the planned melt mass actually entered the water. The test was performed in a closed vessel at an initial pressure of 50 bar. The water was saturated at this temperature and its level was at 1 m height. The simulation starts with the release of 50 kg of simulated corium from an intermediate catcher at about 3.2 m height. The calculation predicts a gradual pressure rise without fast transients worth mentioning from 50 to about 76 bar within roughly one second and stabilizes slightly below the maximum. Also described are the material distributions predicted during the process and the 'mixed' masses according to two different criteria. The former indicate that the melt jet penetrates the water without desintegrating while being surrounded by a thick vapor layer. Subsequently the melt collects at the level bottom and much of the liquid water is blown upwards by the steam being produced. The amounts of mass being 'mixed' with liquid water (and thus are thought to potentially participate in a steam explosion) remain below 10% for the known Theofanous criterion and below 30% for a more conservative criterion. It is however more important that the calculation demonstrates that further mixing could be the result of the onset of a steam explosion. This may strongly limit the usefulness of local mixing criteria. (orig./DG)

  13. Kaliski's explosive driven fusion experiments

    International Nuclear Information System (INIS)

    Marshall, J.

    1979-01-01

    An experiment performed by a group in Poland on the production of DD fusion neutrons by purely explosive means is discussed. A method for multiplying shock velocities ordinarily available from high explosives by a factor of ten is described, and its application to DD fusion experiments is discussed

  14. On-site inspection for the radionuclide observables of an underground nuclear explosion

    International Nuclear Information System (INIS)

    Burnett, J.L.

    2015-01-01

    Under the Comprehensive Nuclear-Test-Ban Treaty an on-site inspection (OSI) may be undertaken to identify signatures from a potential nuclear explosion. This includes the measurement of 17 particulate radionuclides ( 95 Zr, 95 Nb, 99 Mo, 99m Tc, 103 Ru, 106 Rh, 132 Te, 131 I, 132 I, 134 Cs, 137 Cs, 140 Ba, 140 La, 141 Ce, 144 Ce, 144 Pr, 147 Nd). This research provides an assessment of the potential to detect these radionuclides during an OSI within 1 week to 2 years after a nuclear explosion at two locations. A model has been developed that simulates the underground detonation of a 1 kT 235 U nuclear weapon with 1 % venting. This indicates a requirement to minimise the time since detonation with accurate determination of the test location. (author)

  15. The experimental investigation of explosive opening switch

    Energy Technology Data Exchange (ETDEWEB)

    Jiande, Zhang; Huihuang, Zhong; Chuanlu, Li; Yonggui, Liu; Dongqun, Cheng; Xianyang, Peng [National Univ. of Defense Technology, Changsha (China). Dept. of Applied Physics

    1997-12-31

    The explosive opening switch (EOS) used in explosive-driven magnetic-flux compression generator (EMCG) circuits was investigated. It is shown that (1) under certain conditions, the EOS voltage is hardly dependent on the size of the explosive and aluminium foil used in EOS; (2) with the explosive coated by an insulator pipe, the opening effect of EOS is better; (3) by use of EOS, a pulse with 5 kA current, 100 kV voltage and 250 ns risetime has been transferred into a resistance load. (author). 12 figs., 5 refs.

  16. The experimental investigation of explosive opening switch

    International Nuclear Information System (INIS)

    Zhang Jiande; Zhong Huihuang; Li Chuanlu; Liu Yonggui; Cheng Dongqun; Peng Xianyang

    1996-01-01

    The explosive opening switch (EOS) used in explosive-driven magnetic-flux compression generator (EMCG) circuits was investigated. It is shown that (1) under certain conditions, the EOS voltage is hardly dependent on the size of the explosive and aluminium foil used in EOS; (2) with the explosive coated by an insulator pipe, the opening effect of EOS is better; (3) by use of EOS, a pulse with 5 kA current, 100 kV voltage and 250 ns risetime has been transferred into a resistance load. (author). 12 figs., 5 refs

  17. Apparatus for forming an explosively expanded tube-tube sheet joint

    International Nuclear Information System (INIS)

    Schroeder, J.W.

    1984-01-01

    The invention relates to apparatus for expanding a tube into a bore formed in a tube sheet. According to the invention, a primary explosive containing a relatively high number of grains of explosive per unit length extends within the tube coextensive with that portion of the tube to be expanded. An energy transfer cord extends between a detonator and the primary explosive and includes a relatively low number of grains of explosive per unit length which are insufficient to detonate the primary explosive. The transfer cord is covered by a sheath to contain the debris and gases associated with the explosion of the explosive therein. A booster extends between the energy transfer cord and the primary explosive and contains an explosive which can be detonated by the explosive in the energy transfer cord and can, upon exploding, in turn detonate the primary explosive. (author)

  18. Wireless sensor for detecting explosive material

    Science.gov (United States)

    Lamberti, Vincent E; Howell, Jr., Layton N; Mee, David K; Sepaniak, Michael J

    2014-10-28

    Disclosed is a sensor for detecting explosive devices. The sensor includes a ferromagnetic metal and a molecular recognition reagent coupled to the ferromagnetic metal. The molecular recognition reagent is operable to expand upon absorption of vapor from an explosive material such that the molecular recognition reagent changes a tensile stress upon the ferromagnetic metal. The explosive device is detected based on changes in the magnetic switching characteristics of the ferromagnetic metal caused by the tensile stress.

  19. Cosmic Explosions, Life in the Universe, and the Cosmological Constant

    Science.gov (United States)

    Piran, Tsvi; Jimenez, Raul; Cuesta, Antonio J.; Simpson, Fergus; Verde, Licia

    2016-02-01

    Gamma-ray bursts (GRBs) are copious sources of gamma rays whose interaction with a planetary atmosphere can pose a threat to complex life. Using recent determinations of their rate and probability of causing massive extinction, we explore what types of universes are most likely to harbor advanced forms of life. We use cosmological N -body simulations to determine at what time and for what value of the cosmological constant (Λ ) the chances of life being unaffected by cosmic explosions are maximized. Life survival to GRBs favors Lambda-dominated universes. Within a cold dark matter model with a cosmological constant, the likelihood of life survival to GRBs is governed by the value of Λ and the age of the Universe. We find that we seem to live in a favorable point in this parameter space that minimizes the exposure to cosmic explosions, yet maximizes the number of main sequence (hydrogen-burning) stars around which advanced life forms can exist.

  20. Finding the first cosmic explosions. III. Pulsational pair-instability supernovae

    International Nuclear Information System (INIS)

    Whalen, Daniel J.; Smidt, Joseph; Even, Wesley; Fryer, Chris L.; Woosley, S. E.; Heger, Alexander; Stiavelli, Massimo

    2014-01-01

    Population III supernovae have been the focus of growing attention because of their potential to directly probe the properties of the first stars, particularly the most energetic events that can be seen at the edge of the observable universe. But until now pulsational pair-instability supernovae, in which explosive thermonuclear burning in massive stars fails to unbind them but can eject their outer layers into space, have been overlooked as cosmic beacons at the earliest redshifts. These shells can later collide and, like Type IIn supernovae, produce superluminous events in the UV at high redshifts that could be detected in the near infrared today. We present numerical simulations of a 110 M ☉ pulsational pair-instability explosion done with the Los Alamos radiation hydrodynamics code Radiation Adaptive Grid Eulerian. We find that collisions between consecutive pulsations are visible in the near infrared out to z ∼ 15-20 and can probe the earliest stellar populations at cosmic dawn.

  1. Cosmic Explosions, Life in the Universe, and the Cosmological Constant.

    Science.gov (United States)

    Piran, Tsvi; Jimenez, Raul; Cuesta, Antonio J; Simpson, Fergus; Verde, Licia

    2016-02-26

    Gamma-ray bursts (GRBs) are copious sources of gamma rays whose interaction with a planetary atmosphere can pose a threat to complex life. Using recent determinations of their rate and probability of causing massive extinction, we explore what types of universes are most likely to harbor advanced forms of life. We use cosmological N-body simulations to determine at what time and for what value of the cosmological constant (Λ) the chances of life being unaffected by cosmic explosions are maximized. Life survival to GRBs favors Lambda-dominated universes. Within a cold dark matter model with a cosmological constant, the likelihood of life survival to GRBs is governed by the value of Λ and the age of the Universe. We find that we seem to live in a favorable point in this parameter space that minimizes the exposure to cosmic explosions, yet maximizes the number of main sequence (hydrogen-burning) stars around which advanced life forms can exist.

  2. Electromagnetic field effects in explosives

    Science.gov (United States)

    Tasker, Douglas

    2009-06-01

    Present and previous research on the effects of electromagnetic fields on the initiation and detonation of explosives and the electromagnetic properties of explosives are reviewed. Among the topics related to detonating explosives are: measurements of conductivity; enhancement of performance; and control of initiation and growth of reaction. Hayes...()^1 showed a strong correlation of peak electrical conductivity with carbon content of the detonation products. Ershov.......^2 linked detailed electrical conductivity measurements with reaction kinetics and this work was extended to enhance detonation performance electrically;...^3 for this, electrical power densities of the order of 100 TW/m^2 of explosive surface normal to the detonation front were required. However, small electrical powers are required to affect the initiation and growth of reaction.......^4,5 A continuation of this work will be reported. LA-UR 09-00873 .^1 B. Hayes, Procs. of 4th Symposium (International) on Detonation (1965), p. 595. ^2 A. Ershov, P. Zubkov, and L. Luk'yanchikov, Combustion, Explosion, and Shock Waves 10, 776-782 (1974). ^3 M. Cowperthwaite, Procs. 9th Detonation Symposium (1989), p. 388-395. ^4 M. A. Cook and T. Z. Gwyther, ``Influence of Electric Fields on Shock to Detonation Transition,'' (1965). ^5 D. Salisbury, R. Winter, and L. Biddle, Procs. of the APS Topical Conference on Shock Compression of Condensed Matter (2005) p. 1010-1013.

  3. Blast overpressure after tire explosion: a fatal case.

    Science.gov (United States)

    Pomara, Cristoforo; D'Errico, Stefano; Riezzo, Irene; Perilli, Gabriela; Volpe, Umberto; Fineschi, Vittorio

    2013-12-01

    Fatal blast injuries are generally reported in literature as a consequence of the detonation of explosives in war settings. The pattern of lesion depends on the position of the victim in relation to the explosion, on whether the blast tracks through air or water, and whether it happens in the open air or within an enclosed space and the distance from the explosion. Tire explosion-related injuries are rarely reported in literature. This study presents a fatal case of blast overpressure due to the accidental explosion of a truck tire occurring in a tire repair shop. A multidisciplinary approach to the fatality involving forensic pathologists and engineers revealed that the accidental explosion, which caused a series of primary and tertiary blast wave injuries, was due to tire deterioration.

  4. IN-PACKAGE CHEMISTRY ABSTRACTION

    Energy Technology Data Exchange (ETDEWEB)

    E. Thomas

    2005-07-14

    This report was developed in accordance with the requirements in ''Technical Work Plan for Postclosure Waste Form Modeling'' (BSC 2005 [DIRS 173246]). The purpose of the in-package chemistry model is to predict the bulk chemistry inside of a breached waste package and to provide simplified expressions of that chemistry as a function of time after breach to Total Systems Performance Assessment for the License Application (TSPA-LA). The scope of this report is to describe the development and validation of the in-package chemistry model. The in-package model is a combination of two models, a batch reactor model, which uses the EQ3/6 geochemistry-modeling tool, and a surface complexation model, which is applied to the results of the batch reactor model. The batch reactor model considers chemical interactions of water with the waste package materials, and the waste form for commercial spent nuclear fuel (CSNF) waste packages and codisposed (CDSP) waste packages containing high-level waste glass (HLWG) and DOE spent fuel. The surface complexation model includes the impact of fluid-surface interactions (i.e., surface complexation) on the resulting fluid composition. The model examines two types of water influx: (1) the condensation of water vapor diffusing into the waste package, and (2) seepage water entering the waste package as a liquid from the drift. (1) Vapor-Influx Case: The condensation of vapor onto the waste package internals is simulated as pure H{sub 2}O and enters at a rate determined by the water vapor pressure for representative temperature and relative humidity conditions. (2) Liquid-Influx Case: The water entering a waste package from the drift is simulated as typical groundwater and enters at a rate determined by the amount of seepage available to flow through openings in a breached waste package.

  5. IN-PACKAGE CHEMISTRY ABSTRACTION

    International Nuclear Information System (INIS)

    E. Thomas

    2005-01-01

    This report was developed in accordance with the requirements in ''Technical Work Plan for Postclosure Waste Form Modeling'' (BSC 2005 [DIRS 173246]). The purpose of the in-package chemistry model is to predict the bulk chemistry inside of a breached waste package and to provide simplified expressions of that chemistry as a function of time after breach to Total Systems Performance Assessment for the License Application (TSPA-LA). The scope of this report is to describe the development and validation of the in-package chemistry model. The in-package model is a combination of two models, a batch reactor model, which uses the EQ3/6 geochemistry-modeling tool, and a surface complexation model, which is applied to the results of the batch reactor model. The batch reactor model considers chemical interactions of water with the waste package materials, and the waste form for commercial spent nuclear fuel (CSNF) waste packages and codisposed (CDSP) waste packages containing high-level waste glass (HLWG) and DOE spent fuel. The surface complexation model includes the impact of fluid-surface interactions (i.e., surface complexation) on the resulting fluid composition. The model examines two types of water influx: (1) the condensation of water vapor diffusing into the waste package, and (2) seepage water entering the waste package as a liquid from the drift. (1) Vapor-Influx Case: The condensation of vapor onto the waste package internals is simulated as pure H 2 O and enters at a rate determined by the water vapor pressure for representative temperature and relative humidity conditions. (2) Liquid-Influx Case: The water entering a waste package from the drift is simulated as typical groundwater and enters at a rate determined by the amount of seepage available to flow through openings in a breached waste package

  6. Engineering effects of underground nuclear explosions

    International Nuclear Information System (INIS)

    Boardman, Charles R.

    1970-01-01

    Useful effects of contained underground nuclear explosions are discussed in light of today's most promising potential applications. Relevant data obtained through exploration of explosion environments of nine U.S. tests in competent rock are summarized and presented as a practical basis for estimating magnitudes of effects. Effects discussed include chimney configuration, permeability, and volume as well as rubble particle size distributions and extents of permeability change in the chimney wall rock. Explosion mediums include shale, granite, dolomite, and salt. (author)

  7. Engineering effects of underground nuclear explosions

    Energy Technology Data Exchange (ETDEWEB)

    Boardman, Charles R [CER Geonuclear Corporation, Las Vegas, NV (United States)

    1970-05-01

    Useful effects of contained underground nuclear explosions are discussed in light of today's most promising potential applications. Relevant data obtained through exploration of explosion environments of nine U.S. tests in competent rock are summarized and presented as a practical basis for estimating magnitudes of effects. Effects discussed include chimney configuration, permeability, and volume as well as rubble particle size distributions and extents of permeability change in the chimney wall rock. Explosion mediums include shale, granite, dolomite, and salt. (author)

  8. Development of water chemistry diagnosis system for BWR primary loop

    International Nuclear Information System (INIS)

    Nagase, Makoto; Asakura, Yamato; Sakagami, Masaharu; Uchida, Shunsuke; Ohsumi, Katsumi.

    1988-01-01

    The prototype of a water chemistry diagnosis system for BWR primary loop has been developed. Its purposes are improvement of water chemistry control and reduction of the work burden on plant chemistry personnel. It has three main features as follows. (1) Intensifying the observation of water chemistry conditions by variable sampling intervals based on the on-line measured data. (2) Early detection of water chemistry data trends using a second order regression curve which is calculated from the measured data, and then searching the cause of anomaly if anything (3) Diagnosis of Fe concentration in feedwater using model simulations, in order to lower the radiation level in the primary system. (author)

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

    OpenAIRE

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

    2006-01-01

    The sensitive explosives used in initiating devices like primers and detonators are called primary explosives. Successful detonations of secondary explosives are accomplished by suitable sources of initiation energy that is transmitted directly from the primaries or through secondary explosive boosters. Reliable initiating mechanisms are available in numerous forms of primers and detonators depending upon the nature of the secondary explosives. The technology of initiation devices used for mi...

  10. Effects from airplane crashes and gas explosions to Leningrad nuclear plant

    International Nuclear Information System (INIS)

    Junttila, K.; Varpasuo, P.

    1998-01-01

    In this study the effects of aircraft crash and gas explosion to Leningrad Nuclear Power Plant has been researched. One of the two reactor buildings is modeled with finite element method using the pre-processor program MSC/PATRAN and analyzed with MSC/NASTRAN analysis program. In MSC/PATRAN or FEMAP, which is a pre-processor program of MSC/NASTRAN for Windows, the reactor building of the plant has been modeled with shell and beam elements and the load sets describing the aircraft crash and gas explosion have been developed. The crash loads are from Cessna 210 civil airplane crash with impact velocity 360 km/h and maximum impact force of 7 MN and Phantom RF-43 military airplane crash with impact velocity 215 m/s and with maximum impact force of 110 MN. The gas explosion pressure wave simulates the deflagration wave with maximum pressure of 0,045 MPa. Seven Cessna 210 airplane crash locations, two Phantom RF-43 airplane crash locations and one gas explosion load case is modeled. Airplane crash loads were from different directions and to different points of impact in the reactor building. The gas explosion load was assumed to affect the reactor building from one side parallel to one of the global coordinate axes of the model. With MSC/NASTRAN reactions from loads are analyzed. All loads were timedependent; their magnitude varied with time and consequently the analysis was carried out with the aid of transient response analysis. Time step in Cessna 210 analysis was 0,003 s and in Phantom RF-43 and gas explosion analyses 0,01 s. The greatest displacement from Cessna 210 loads was 12 mm and from Phantom RF-43 load 344 mm. The last value shows that construction would fail with that load. The greatest displacement from gas explosion load was 68 mm. Stresses are not so interesting in this preliminary analysis of the effects, but they are shown in pictures embedded in the report text. Displacements were greatest in upper part of the reactor building, where no intersections

  11. Laser-based optical detection of explosives

    CERN Document Server

    Pellegrino, Paul M; Farrell, Mikella E

    2015-01-01

    Laser-Based Optical Detection of Explosives offers a comprehensive review of past, present, and emerging laser-based methods for the detection of a variety of explosives. This book: Considers laser propagation safety and explains standard test material preparation for standoff optical-based detection system evaluation Explores explosives detection using deep ultraviolet native fluorescence, Raman spectroscopy, laser-induced breakdown spectroscopy, reflectometry, and hyperspectral imaging Examines photodissociation followed by laser-induced fluorescence, photothermal methods, cavity-enhanced absorption spectrometry, and short-pulse laser-based techniques Describes the detection and recognition of explosives using terahertz-frequency spectroscopic techniques Each chapter is authored by a leading expert on the respective technology, and is structured to supply historical perspective, address current advantages and challenges, and discuss novel research and applications. Readers are left with an in-depth understa...

  12. Diagnosis and Modeling of the Explosive Development of Winter Storms: Sensitivity to PBL Schemes

    Science.gov (United States)

    Liberato, Margarida L. R.; Pradhan, Prabodha K.

    2014-05-01

    The correct representation of extreme windstorms in regional models is of great importance for impact studies of climate change. The Iberian Peninsula has recently witnessed major damage from winter extratropical intense cyclones like Klaus (January 2009), Xynthia (February 2010) and Gong (January 2013) which formed over the mid-Atlantic, experienced explosive intensification while travelling eastwards at lower latitudes than usual [Liberato et al. 2011; 2013]. In this paper the explosive development of these storms is simulated by the advanced mesoscale Weather Research and Forecasting Model (WRF v 3.4.1), initialized with NCEP Final Analysis (FNL) data as initial and lateral boundary conditions (boundary conditions updated in every 3 hours intervals). The simulation experiments are conducted with two domains, a coarser (25km) and nested (8.333km), covering the entire North Atlantic and Iberian Peninsula region. The characteristics of these storms (e.g. wind speed, precipitation) are studied from WRF model and compared with multiple observations. In this context simulations with different Planetary Boundary Layer (PBL) schemes are performed. This approach aims at understanding which mechanisms favor the explosive intensification of these storms at a lower than usual latitudes, thus improving the knowledge of atmospheric dynamics (including small-scale processes) on controlling the life cycle of midlatitude extreme storms and contributing to the improvement in predictability and in our ability to forecast storms' impacts over Iberian Peninsula. Acknowledgments: This work was partially supported by FEDER (Fundo Europeu de Desenvolvimento Regional) funds through the COMPETE (Programa Operacional Factores de Competitividade) and by national funds through FCT (Fundação para a Ciência e a Tecnologia, Portugal) under project STORMEx FCOMP-01-0124-FEDER- 019524 (PTDC/AAC-CLI/121339/2010). References: Liberato M.L.R., J.G. Pinto, I.F. Trigo, R.M. Trigo (2011) Klaus - an

  13. Planar compaction of ceramic powders with mining explosives

    International Nuclear Information System (INIS)

    Stuivinga, M.; Verbeek, H.J.; Carton, E.P.

    2000-01-01

    Shock compaction experiments of B 4 C powders have been performed using a planar configuration. The powders were contained between metal plates. On top of the upper plate, having a thickness of about 10 mm, was a layer of mining explosives. For this configuration, computer simulations have been performed with use of the hydrocode Autodyn. In comparison with the cylindrical compaction process the planar compaction process appears to be quite different. The reason is the very low detonation velocity of the used mining explosives (2-4 km/s), which is much lower than the sound and shock speeds of the steel plate, in combination with the relatively large thickness of the metal layer. As a result, the nature of the compaction process of the powder initially more resembles a quasi-static compaction process than a shock compaction process. Due to the quasi-static nature of the compaction, the pressure release in the powder after compression is very gradual. Therefore, no strong rarefaction waves leading to high tensile stresses in the compact arise. Flat plates (10x10 cm, 0.6-0.8 cm thick) of Al (20-30 vol %) infiltrated B 4 C have been fabricated using this configuration

  14. Review of Soviet studies related to peaceful underground nuclear explosions

    International Nuclear Information System (INIS)

    Lin, W.

    1978-01-01

    Theoretical and empirical studies of contained and crater-forming underground nuclear explosions by USSR investigators are reviewed and summarized. Published data on U.S., USSR, and French cavity-forming nuclear explosions are compared with those predicted by the formula. Empirical studies on U.S. and USSR cratering explosions, both high explosions, both high explosive and nuclear are summarized. The parameters governing an excavation explosion are reviewed

  15. In-Package Chemistry Abstraction

    Energy Technology Data Exchange (ETDEWEB)

    E. Thomas

    2004-11-09

    This report was developed in accordance with the requirements in ''Technical Work Plan for: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]). The purpose of the in-package chemistry model is to predict the bulk chemistry inside of a breached waste package and to provide simplified expressions of that chemistry as function of time after breach to Total Systems Performance Assessment for the License Application (TSPA-LA). The scope of this report is to describe the development and validation of the in-package chemistry model. The in-package model is a combination of two models, a batch reactor model that uses the EQ3/6 geochemistry-modeling tool, and a surface complexation model that is applied to the results of the batch reactor model. The batch reactor model considers chemical interactions of water with the waste package materials and the waste form for commercial spent nuclear fuel (CSNF) waste packages and codisposed waste packages that contain both high-level waste glass (HLWG) and DOE spent fuel. The surface complexation model includes the impact of fluid-surface interactions (i.e., surface complexation) on the resulting fluid composition. The model examines two types of water influx: (1) the condensation of water vapor that diffuses into the waste package, and (2) seepage water that enters the waste package from the drift as a liquid. (1) Vapor Influx Case: The condensation of vapor onto the waste package internals is simulated as pure H2O and enters at a rate determined by the water vapor pressure for representative temperature and relative humidity conditions. (2) Water Influx Case: The water entering a waste package from the drift is simulated as typical groundwater and enters at a rate determined by the amount of seepage available to flow through openings in a breached waste package. TSPA-LA uses the vapor influx case for the nominal scenario for simulations where the waste

  16. In-Package Chemistry Abstraction

    International Nuclear Information System (INIS)

    E. Thomas

    2004-01-01

    This report was developed in accordance with the requirements in ''Technical Work Plan for: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]). The purpose of the in-package chemistry model is to predict the bulk chemistry inside of a breached waste package and to provide simplified expressions of that chemistry as function of time after breach to Total Systems Performance Assessment for the License Application (TSPA-LA). The scope of this report is to describe the development and validation of the in-package chemistry model. The in-package model is a combination of two models, a batch reactor model that uses the EQ3/6 geochemistry-modeling tool, and a surface complexation model that is applied to the results of the batch reactor model. The batch reactor model considers chemical interactions of water with the waste package materials and the waste form for commercial spent nuclear fuel (CSNF) waste packages and codisposed waste packages that contain both high-level waste glass (HLWG) and DOE spent fuel. The surface complexation model includes the impact of fluid-surface interactions (i.e., surface complexation) on the resulting fluid composition. The model examines two types of water influx: (1) the condensation of water vapor that diffuses into the waste package, and (2) seepage water that enters the waste package from the drift as a liquid. (1) Vapor Influx Case: The condensation of vapor onto the waste package internals is simulated as pure H2O and enters at a rate determined by the water vapor pressure for representative temperature and relative humidity conditions. (2) Water Influx Case: The water entering a waste package from the drift is simulated as typical groundwater and enters at a rate determined by the amount of seepage available to flow through openings in a breached waste package. TSPA-LA uses the vapor influx case for the nominal scenario for simulations where the waste package has been

  17. Inhomogeneous wire explosion in water

    International Nuclear Information System (INIS)

    Hwangbo, C.K.; Kong, H.J.; Lee, S.S.

    1980-01-01

    Inhomogeneous processes are observed in underwater copper wire explosion induced by a condensed capacitor discharge. The wire used is 0.1 mm in diameter and 10 mm long, and the capacitor of 2 μF is charged to 5 KV. A N 2 laser is used for the diagnostic of spatial extension of exploding copper vapour. The photographs obtained in this experiment show unambiguously the inhomogeneous explosion along the exploding wire. The quenching of plasma by the surrounding water inhibits the expansion of the vapour. It is believed the observed inhomogeneous explosion along the wire is located and localized around Goronkin's striae, which was first reported by Goronkin and discussed by Froengel as a pre-breakdown phenomenon. (author)

  18. Water waves generated by underwater explosion

    CERN Document Server

    Mehaute, Bernard Le

    1996-01-01

    This is the first book on explosion-generated water waves. It presents the theoretical foundations and experimental results of the generation and propagation of impulsively generated waves resulting from underwater explosions. Many of the theories and concepts presented herein are applicable to other types of water waves, in particular, tsunamis and waves generated by the fall of a meteorite. Linear and nonlinear theories, as well as experimental calibrations, are presented for cases of deep and shallow water explosions. Propagation of transient waves on dissipative, nonuniform bathymetries to

  19. Ideas for peaceful nuclear explosions in USSR

    International Nuclear Information System (INIS)

    1970-01-01

    Three papers prepared in USSR have been made available to the Agency for circulation among Member States. One examines radioactive contamination and methods for predicting it, of natural environments during underground explosions. Another deals with the mechanical effect of underground explosions. The third, which forms the basis of this article, reviews possible applications of peaceful nuclear explosions in the Soviet economy. (author)

  20. Inelastic processes in seismic wave generation by underground explosions

    Energy Technology Data Exchange (ETDEWEB)

    Rodean, H.C.

    1980-08-01

    Theories, computer calculations, and measurements of spherical stress waves from explosions are described and compared, with emphasis on the transition from inelastic to almost-elastic relations between stress and strain. Two aspects of nonspherical explosion geometry are considered: tectonic strain release and surface spall. Tectonic strain release affects the generation of surface waves; spall closure may also. The reduced-displacement potential is a common solution (the equivalent elastic source) of the forward and inverse problems, assuming a spherical source. Measured reduced-displacement potentials are compared with potentials calculated as solutions of the direct and inverse problems; there are significant differences between the results of the two types of calculations and between calculations and measurements. The simple spherical model of an explosion is not sufficient to account for observations of explosions over wide ranges of depth and yield. The explosion environment can have a large effect on explosion detection and yield estimation. The best sets of seismic observations for use in developing discrimination techniques are for high-magnitude high-yield explosions; the identification problem is most difficult for low-magnitude low-yield explosions. Most of the presently available explosion data (time, medium, depth, yield, etc.) are for explosions in a few media at the Nevada Test Site; some key questions concerning magnitude vs yield and m/sub b/ vs M/sub s/ relations can be answered only by data for explosions in other media at other locations.

  1. Inelastic processes in seismic wave generation by underground explosions

    International Nuclear Information System (INIS)

    Rodean, H.C.

    1980-01-01

    Theories, computer calculations, and measurements of spherical stress waves from explosions are described and compared, with emphasis on the transition from inelastic to almost-elastic relations between stress and strain. Two aspects of nonspherical explosion geometry are considered: tectonic strain release and surface spall. Tectonic strain release affects the generation of surface waves; spall closure may also. The reduced-displacement potential is a common solution (the equivalent elastic source) of the forward and inverse problems, assuming a spherical source. Measured reduced-displacement potentials are compared with potentials calculated as solutions of the direct and inverse problems; there are significant differences between the results of the two types of calculations and between calculations and measurements. The simple spherical model of an explosion is not sufficient to account for observations of explosions over wide ranges of depth and yield. The explosion environment can have a large effect on explosion detection and yield estimation. The best sets of seismic observations for use in developing discrimination techniques are for high-magnitude high-yield explosions; the identification problem is most difficult for low-magnitude low-yield explosions. Most of the presently available explosion data (time, medium, depth, yield, etc.) are for explosions in a few media at the Nevada Test Site; some key questions concerning magnitude vs yield and m/sub b/ vs M/sub s/ relations can be answered only by data for explosions in other media at other locations

  2. Radon, water chemistry and pollution check by volatile organic compounds in springs around Popocatepetl volcano, Mexico

    Directory of Open Access Journals (Sweden)

    M. Mena

    2005-06-01

    Full Text Available Popocatepetl volcano is a high-risk active volcano in Central Mexico where the highest population density in the country is settled. Radon in the soil and groundwater together with water chemistry from samples of nearby springs were analysed as a function of the 2002-2003 volcanic activity. The measurements of soil radon indicated fluctuations related to both the meteorological and sporadic explosive events. Groundwater radon showed essential differences in concentration due to the specific characteristics of the studied springs. Water chemistry showed also stability along the monitoring period. No anthropogenic pollution from Volatile Organic Compounds (VOCs was observed. An overview of the soil radon behaviour as a function of the volcanic activity in the period 1994-2002 is also discussed.

  3. The atmospheric chemistry general circulation model ECHAM5/MESSy1: consistent simulation of ozone from the surface to the mesosphere

    Directory of Open Access Journals (Sweden)

    P. Jöckel

    2006-01-01

    Full Text Available The new Modular Earth Submodel System (MESSy describes atmospheric chemistry and meteorological processes in a modular framework, following strict coding standards. It has been coupled to the ECHAM5 general circulation model, which has been slightly modified for this purpose. A 90-layer model setup up to 0.01 hPa was used at spectral T42 resolution to simulate the lower and middle atmosphere. With the high vertical resolution the model simulates the Quasi-Biennial Oscillation. The model meteorology has been tested to check the influence of the changes to ECHAM5 and the radiation interactions with the new representation of atmospheric composition. In the simulations presented here a Newtonian relaxation technique was applied in the tropospheric part of the domain to weakly nudge the model towards the analysed meteorology during the period 1998–2005. This allows an efficient and direct evaluation with satellite and in-situ data. It is shown that the tropospheric wave forcing of the stratosphere in the model suffices to reproduce major stratospheric warming events leading e.g. to the vortex split over Antarctica in 2002. Characteristic features such as dehydration and denitrification caused by the sedimentation of polar stratospheric cloud particles and ozone depletion during winter and spring are simulated well, although ozone loss in the lower polar stratosphere is slightly underestimated. The model realistically simulates stratosphere-troposphere exchange processes as indicated by comparisons with satellite and in situ measurements. The evaluation of tropospheric chemistry presented here focuses on the distributions of ozone, hydroxyl radicals, carbon monoxide and reactive nitrogen compounds. In spite of minor shortcomings, mostly related to the relatively coarse T42 resolution and the neglect of inter-annual changes in biomass burning emissions, the main characteristics of the trace gas distributions are generally reproduced well. The MESSy

  4. The fracture of concrete under explosive shock loading

    International Nuclear Information System (INIS)

    Watson, A.J.; Sanderson, A.J.

    1982-01-01

    Concrete fracture close to the point of application of high explosive shock pressures has been studied experimentally by placing an explosive charge on the edge of a concrete slab. The extent of the crushing and cracking produced by a semi cylindrical diverging plane compressive stress pulse has been measured and complementary experiments gave the pressure transmitted at an explosive to concrete interface and the stress-strain relation for concrete at explosive strain rates. (orig.) [de

  5. Novel process windows for enabling, accelerating, and uplifting flow chemistry.

    Science.gov (United States)

    Hessel, Volker; Kralisch, Dana; Kockmann, Norbert; Noël, Timothy; Wang, Qi

    2013-05-01

    Novel Process Windows make use of process conditions that are far from conventional practices. This involves the use of high temperatures, high pressures, high concentrations (solvent-free), new chemical transformations, explosive conditions, and process simplification and integration to boost synthetic chemistry on both the laboratory and production scale. Such harsh reaction conditions can be safely reached in microstructured reactors due to their excellent transport intensification properties. This Review discusses the different routes towards Novel Process Windows and provides several examples for each route grouped into different classes of chemical and process-design intensification. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Investigation of Varied Strontium-Transuranic Precipitation Chemistries for Crossflow

    International Nuclear Information System (INIS)

    Nash, C.A.

    2000-01-01

    Precipitation chemistries for strontium and transuranic (TRU) removal have been tested for crossflow filterability and lanthanide removal with simulants of Hanford tank 241-AN-107 supernate. This is the initial work indicating the usefulness of a strontium and permanganate precipitation process as applied to the Hanford River Protection Project. Precipitations with both ferric and ferrous iron were shown to be at least two orders of magnitude less filterable than a 0.1 gpm/ft target average flux that was desired at the time. A precipitate from a strontium nitrate strike alone was found to filter easily and to make the desired average flux. Other chemistries tested included precipitant of lanthanum(III), nickel (II), calcium (II), and a redox chemistry using sodium permanganate. Of these chemistries a strontium and permanganate strike including calcium provided the highest filter flux compared to the other chemistries. It showed the most promise in lanthanide removal as well. This work provides a promising direction for further work to achieve both acceptable filterability and decontamination for Envelope C wastes to be treated by the Hanford River Protection Project. The work reported here was originally intended to satisfy needs for crossflow filter testing of a strontium and ferric precipitation method for treating Envelope C using a 241-AN-107 simulant

  7. Investigation of Varied Strontium-Transuranic Precipitation Chemistries for Crossflow

    Energy Technology Data Exchange (ETDEWEB)

    Nash, C.A.

    2000-07-27

    Precipitation chemistries for strontium and transuranic (TRU) removal have been tested for crossflow filterability and lanthanide removal with simulants of Hanford tank 241-AN-107 supernate. This is the initial work indicating the usefulness of a strontium and permanganate precipitation process as applied to the Hanford River Protection Project. Precipitations with both ferric and ferrous iron were shown to be at least two orders of magnitude less filterable than a 0.1 gpm/ft target average flux that was desired at the time. A precipitate from a strontium nitrate strike alone was found to filter easily and to make the desired average flux. Other chemistries tested included precipitant of lanthanum(III), nickel (II), calcium (II), and a redox chemistry using sodium permanganate. Of these chemistries a strontium and permanganate strike including calcium provided the highest filter flux compared to the other chemistries. It showed the most promise in lanthanide removal as well. This work provides a promising direction for further work to achieve both acceptable filterability and decontamination for Envelope C wastes to be treated by the Hanford River Protection Project. The work reported here was originally intended to satisfy needs for crossflow filter testing of a strontium and ferric precipitation method for treating Envelope C using a 241-AN-107 simulant.

  8. Insensitive detonator apparatus for initiating large failure diameter explosives

    Science.gov (United States)

    Perry, III, William Leroy

    2015-07-28

    A munition according to a preferred embodiment can include a detonator system having a detonator that is selectively coupled to a microwave source that functions to selectively prime, activate, initiate, and/or sensitize an insensitive explosive material for detonation. The preferred detonator can include an explosive cavity having a barrier within which an insensitive explosive material is disposed and a waveguide coupled to the explosive cavity. The preferred system can further include a microwave source coupled to the waveguide such that microwaves enter the explosive cavity and impinge on the insensitive explosive material to sensitize the explosive material for detonation. In use the preferred embodiments permit the deployment and use of munitions that are maintained in an insensitive state until the actual time of use, thereby substantially preventing unauthorized or unintended detonation thereof.

  9. Underground Nuclear Explosions and Release of Radioactive Noble Gases

    Science.gov (United States)

    Dubasov, Yuri V.

    2010-05-01

    Over a period in 1961-1990 496 underground nuclear tests and explosions of different purpose and in different rocks were conducted in the Soviet Union at Semipalatinsk and anovaya Zemlya Test Sites. A total of 340 underground nuclear tests were conducted at the Semipalatinsk Test Site. One hundred seventy-nine explosions (52.6%) among them were classified as these of complete containment, 145 explosions (42.6%) as explosions with weak release of radioactive noble gases (RNG), 12 explosions (3.5%) as explosions with nonstandard radiation situation, and four excavation explosions with ground ejection (1.1%). Thirty-nine nuclear tests had been conducted at the Novaya Zemlya Test Site; six of them - in shafts. In 14 tests (36%) there were no RNG release. Twenty-three tests have been accompanied by RNG release into the atmosphere without sedimental contamination. Nonstandard radiation situation occurred in two tests. In incomplete containment explosions both early-time RNG release (up to ~1 h) and late-time release from 1 to 28 h after the explosion were observed. Sometimes gas release took place for several days, and it occurred either through tunnel portal or epicentral zone, depending on atmospheric air temperature.

  10. Establishment of data base of regional seismic recordings from earthquakes, chemical explosions and nuclear explosions in the Former Soviet Union

    Energy Technology Data Exchange (ETDEWEB)

    Ermolenko, N.A.; Kopnichev, Yu.F.; Kunakov, V.G.; Kunakova, O.K.; Rakhmatullin, M.Kh.; Sokolova, I.N.; Vybornyy, Zh.I. [AN SSSR, Moscow (Russian Federation). Inst. Fiziki Zemli

    1995-06-01

    In this report results of work on establishment of a data base of regional seismic recordings from earthquakes, chemical explosions and nuclear explosions in the former Soviet Union are described. This work was carried out in the Complex Seismological Expedition (CSE) of the Joint Institute of Physics of the Earth of the Russian Academy of Sciences and Lawrence Livermore National Laboratory. The recording system, methods of investigations and primary data processing are described in detail. The largest number of digital records was received by the permanent seismic station Talgar, situated in the northern Tien Shan, 20 km to the east of Almaty city. More than half of the records are seismograms of underground nuclear explosions and chemical explosions. The nuclear explosions were recorded mainly from the Semipalatinsk test site. In addition, records of the explosions from the Chinese test site Lop Nor and industrial nuclear explosions from the West Siberia region were obtained. Four records of strong chemical explosions were picked out (two of them have been produced at the Semipalatinsk test site and two -- in Uzbekistan). We also obtained 16 records of crustal earthquakes, mainly from the Altai region, close to the Semipalatinsk test site, and also from the West China region, close to the Lop Nor test site. In addition, a small number of records of earthquakes and underground nuclear explosions, received by arrays of temporary stations, that have been working in the southern Kazakhstan region are included in this report. Parameters of the digital seismograms and file structure are described. Possible directions of future work on the digitizing of unique data archive are discussed.

  11. Workshop on explosions, BLEVEs, fires, etc.

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    The purpose of this workshop will be to provide a bridge between engineering practices, modeling, and measurement of fires and explosions, and use this information in a practical manner to improve the fire safety of the process facility. New techniques and information are available on the means to prevent, predict and mitigate fires and explosions. A review of BLEVEs and methods for preventing and protecting against the effects of BLEVES in large petrochemical facilities. Observations and the use of models that have been successful in predicting the effects of vapor explosions for the prevention of collapse of structures and mitigation of the effects of vapor explosions in process facilities are presented. Recent work involving the measurement of radiation from large jet fires at the Kuwaiti oil fields and fire tests of crude oil spills on the sea is discussed. Fire radiation measurement can be used to predict effects on structures, facilities, and the complexity of fire fighting operations required for control of spill and pool fires. Practical applications of techniques for prevention and control of explosions within building, resulting from failures of autoclaves or release of flammable gas to the atmosphere of the building are discussed.

  12. What factors control superficial lava dome explosivity?

    Science.gov (United States)

    Boudon, Georges; Balcone-Boissard, Hélène; Villemant, Benoît; Morgan, Daniel J

    2015-09-30

    Dome-forming eruption is a frequent eruptive style and a major hazard on numerous volcanoes worldwide. Lava domes are built by slow extrusion of degassed, viscous magma and may be destroyed by gravitational collapse or explosion. The triggering of lava dome explosions is poorly understood: here we propose a new model of superficial lava-dome explosivity based upon a textural and geochemical study (vesicularity, microcrystallinity, cristobalite distribution, residual water contents, crystal transit times) of clasts produced by key eruptions. Superficial explosion of a growing lava dome may be promoted through porosity reduction caused by both vesicle flattening due to gas escape and syn-eruptive cristobalite precipitation. Both processes generate an impermeable and rigid carapace allowing overpressurisation of the inner parts of the lava dome by the rapid input of vesiculated magma batches. The relative thickness of the cristobalite-rich carapace is an inverse function of the external lava dome surface area. Explosive activity is thus more likely to occur at the onset of lava dome extrusion, in agreement with observations, as the likelihood of superficial lava dome explosions depends inversely on lava dome volume. This new result is of interest for the whole volcanological community and for risk management.

  13. Containment Sodium Chemistry Models in MELCOR.

    Energy Technology Data Exchange (ETDEWEB)

    Louie, David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Humphries, Larry L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Denman, Matthew R [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-04-01

    To meet regulatory needs for sodium fast reactors’ future development, including licensing requirements, Sandia National Laboratories is modernizing MELCOR, a severe accident analysis computer code developed for the U.S. Nuclear Regulatory Commission (NRC). Specifically, Sandia is modernizing MELCOR to include the capability to model sodium reactors. However, Sandia’s modernization effort primarily focuses on the containment response aspects of the sodium reactor accidents. Sandia began modernizing MELCOR in 2013 to allow a sodium coolant, rather than water, for conventional light water reactors. In the past three years, Sandia has been implementing the sodium chemistry containment models in CONTAIN-LMR, a legacy NRC code, into MELCOR. These chemistry models include spray fire, pool fire and atmosphere chemistry models. Only the first two chemistry models have been implemented though it is intended to implement all these models into MELCOR. A new package called “NAC” has been created to manage the sodium chemistry model more efficiently. In 2017 Sandia began validating the implemented models in MELCOR by simulating available experiments. The CONTAIN-LMR sodium models include sodium atmosphere chemistry and sodium-concrete interaction models. This paper presents sodium property models, the implemented models, implementation issues, and a path towards validation against existing experimental data.

  14. Use of explosives in pipeline construction work

    Energy Technology Data Exchange (ETDEWEB)

    Ball, M J

    1976-08-01

    Explosives are an essential tool in Great Britain's pipeline-construction industry, with applications on dry land and under water, in trench blasting and tunneling for road and service crossings, demolition of unwanted sections, and removal of coatings. Nobels Explosive Co. Ltd. describes basic explosives operations as pertaining to the requirements of rock trenching, submarine operations, thrust-bore and tunneling operations, demolitions, and precision blasting.

  15. Response of HEPA filters to simulated-accident conditions

    International Nuclear Information System (INIS)

    Gregory, W.S.; Martin, R.A.; Smith, P.R.; Fenton, D.E.

    1982-01-01

    High-efficiency particulate air (HEPA) filters have been subjected to simulated accident conditions to determine their response to abnormal operating events. Both domestic and European standard and high-capacity filters have been evaluated to determine their response to simulated fire, explosion, and tornado conditions. The HEPA filter structural limitations for tornado and explosive loadings are discussed. In addition, filtration efficiencies during these accident conditions are reported for the first time. Our data indicate efficiencies between 80% and 90% for shock loadings below the structural limit level. We describe two types of testing for ineffective filtration - clean filters exposed to pulse-entrained aerosol and dirty filters exposed to tornado and shock pulses. Efficiency and material loss data are described. Also, the resonse of standard HEPA filters to simulated fire conditions is presented. We describe a unique method of measuring accumulated combustion products on the filter. Additionally, data relating to pressure drop vs accumulated mass during plugging are reported for simulated combustion aerosols. The effects of concentration and moisture levels on filter plugging were evaluated. We are obtaining all of the above data so that mathematical models can be developed for fire, explosion, and tornado accident analysis computer codes. These computer codes can be used to assess the response of nuclear air cleaning systems to accident conditions

  16. Protostellar accretion traced with chemistry

    DEFF Research Database (Denmark)

    Frimann, Søren; Jørgensen, Jes Kristian; Padoan, Paolo

    2016-01-01

    used foranalysing the observations. Methods: Simple freeze-out andsublimation chemistry is added to the simulation, and syntheticC18O line cubes are created for a large number of simulatedprotostars. The spatial extent of C18O is measured for thesimulated protostars and compared directly to a sample...

  17. Effects of ozone chemistry and outside air supply on passenger self-evalua-tion of symptoms during 4-hour exposures in a simulated aircraft cabin

    DEFF Research Database (Denmark)

    Strøm-Tejsen, Peter; Tamás, Gyöngyi; Myśków, Danuta

    2006-01-01

    Experiments were carried out in a simulated 21-seat section of an aircraft cabin, installed in a climate chamber, to determine the extent to which cabin air quality and passenger symptoms are affected by ozone chemistry. A total of 30 subjects were exposed to four conditions: two rates of outside...

  18. Burn propagation in a PBX 9501 thermal explosion

    International Nuclear Information System (INIS)

    Henson, B. F.; Smilowitz, L.; Romero, J. J.; Sandstrom, M. M.; Asay, B. W.; Schwartz, C.; Saunders, A.; Merrill, F.; Morris, C.; Murray, M. M.; McNeil, W. V.; Marr-Lyon, M.; Rightley, P. M.

    2007-01-01

    We have applied proton radiography to study the conversion of solid density to gaseous combustion products subsequent to ignition of a thermal explosion in PBX 9501. We apply a thermal boundary condition to the cylindrical walls of the case, ending with an induction period at 205 C. We then introduce a laser pulse that accelerates the thermal ignition and synchronizes the explosion with the proton accelerator. We then obtain fast, synchronized images of the evolution of density loss with few microsecond resolution during the approximately 100 microsecond duration of the explosion. We present images of the solid explosive during the explosion and discuss measured rates and assumed mechanisms of burning the role of pressure in this internal burning

  19. Determining the explosion risk level and the explosion hazard area for a group of natural gas wells

    Science.gov (United States)

    Gligor, A.; Petrescu, V.; Deac, C.; Bibu, M.

    2016-11-01

    Starting from the fact that the natural gas engineering profession is generally associated with a high occupational risk, the current paper aims to help increase the safety of natural gas wells and reduce the risk of work-related accidents, as well as the occurrence of professional illnesses, by applying an assessment method that has proven its efficiency in other industrial areas in combination with a computer-aided design software. More specifically, the paper focuses on two main research directions: assessing the explosion risk for employees working at natural gas wells and indicating areas with a higher explosion hazard by using a modern software that allows their presentation in 3D. The appropriate zoning of industrial areas allows to group the various functional areas function of the probability of the occurrence of a dangerous element, such as an explosive atmosphere and subsequently it allows also to correctly select the electrical and mechanical equipment that will be used in that area, since electrical apparatuses that are otherwise found in normal work environments cannot generally be used in areas with explosion hazard, because of the risk that an electric spark, an electrostatic discharge etc. ignites the explosive atmosphere.

  20. Relativistic quantum chemistry on quantum computers

    Czech Academy of Sciences Publication Activity Database

    Veis, Libor; Višňák, Jakub; Fleig, T.; Knecht, S.; Saue, T.; Visscher, L.; Pittner, Jiří

    2012-01-01

    Roč. 85, č. 3 (2012), 030304 ISSN 1050-2947 R&D Projects: GA ČR GA203/08/0626 Institutional support: RVO:61388955 Keywords : simulation * algorithm * computation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.042, year: 2012