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Sample records for explosive flux compression

  1. Railguns powered by explosive driven flux compression generators

    International Nuclear Information System (INIS)

    Fowler, C.M.; Zimmermann, E.L.; Cummings, C.E.

    1986-01-01

    Explosive driven flux compression generators (FCG's) are single-shot devices that convert part of the energy of high explosives into electromagnetic energy. Some classes of these generators have served quite well as railgun power sources. In this paper and the following paper we describe strip and helical type FCG's, both of which are in use in the Los Alamos railgun program. Advantages and disadvantages these generators have for railgun power supplies will be discussed, together with experimental results obtained and some of the diagnostics we have found particularly useful

  2. Explosive magnetic flux compression plate generators as fast high-energy power sources

    International Nuclear Information System (INIS)

    Caird, R.S.; Erickson, D.J.; Garn, W.B.; Fowler, C.M.

    1976-01-01

    A type of explosive driven generator, called a plate generator, is described. It is capable of delivering electrical energies in the MJ range at TW power levels. Plane wave detonated explosive systems accelerate two large-area metal plates to high opposing velocities. An initial magnetic field is compressed and the flux transferred to an external load. The characteristics of the plate generator are described and compared with those of other types of generators. Methods of load matching are discussed. The results of several high-power experiments are also given

  3. Explosively formed fuse opening switches for use in flux-compression generator circuits

    International Nuclear Information System (INIS)

    Goforth, J.H.; Marsh, S.P.

    1990-01-01

    Explosive-driven magnetic flux compression generators (explosive generators) provide for the generation of large amounts of energy compactly stored in a magnetic field. Opening switches for use in explosive generator circuits allow the energy to be used for applications requiring higher power than can be developed by the generators themselves. The authors have developed a type of opening switch that they describe as an explosively formed fuse (EEF). These switches are well suited to explosive generator circuits and provide a considerable enhancement of explosive pulsed-power capability. The authors first experiments with explosively formed fuses occurred while attempting to utilize the enhanced pressure developed in the high-pressure interaction between two detonation fronts. In these tests they attempted to use the interaction to sever conducting plates along lines perpendicular to current flow. The technique worked to some extent, and to ascertain how much advantage was gained from the high-pressure interaction, they substituted an areal detonation in place of the discrete lines required to produce lines of interaction. This paper describes the authors development effort, the state of the art, and the different manifestations of their technique

  4. Flux compression generators as plasma compression power sources

    International Nuclear Information System (INIS)

    Fowler, C.M.; Caird, R.S.; Erickson, D.J.; Freeman, B.L.; Thomson, D.B.; Garn, W.B.

    1979-01-01

    A survey is made of applications where explosive-driven magnetic flux compression generators have been or can be used to directly power devices that produce dense plasmas. Representative examples are discussed that are specific to the theta pinch, the plasma gun, the dense plasma focus and the Z pinch. These examples are used to illustrate the high energy and power capabilities of explosive generators. An application employing a rocket-borne, generator-powered plasma gun emphasizes the size and weight potential of flux compression power supplies. Recent results from a local effort to drive a dense plasma focus are provided. Imploding liners ae discussed in the context of both the theta and Z pinches

  5. Fast modeling of flux trapping cascaded explosively driven magnetic flux compression generators.

    Science.gov (United States)

    Wang, Yuwei; Zhang, Jiande; Chen, Dongqun; Cao, Shengguang; Li, Da; Liu, Chebo

    2013-01-01

    To predict the performance of flux trapping cascaded flux compression generators, a calculation model based on an equivalent circuit is investigated. The system circuit is analyzed according to its operation characteristics in different steps. Flux conservation coefficients are added to the driving terms of circuit differential equations to account for intrinsic flux losses. To calculate the currents in the circuit by solving the circuit equations, a simple zero-dimensional model is used to calculate the time-varying inductance and dc resistance of the generator. Then a fast computer code is programmed based on this calculation model. As an example, a two-staged flux trapping generator is simulated by using this computer code. Good agreements are achieved by comparing the simulation results with the measurements. Furthermore, it is obvious that this fast calculation model can be easily applied to predict performances of other flux trapping cascaded flux compression generators with complex structures such as conical stator or conical armature sections and so on for design purpose.

  6. The Grenoble station for producing strong transient magnetic fields higher than 100 teslas by an explosive driven flux compression

    International Nuclear Information System (INIS)

    Guillot, M.

    1976-01-01

    Reproducible transient magnetic fields up to 400 teslas (4 megaoersted) are achieved by a simple explosive driven flux compression. The results are described simply from the point of view of energy conversion. The problems of field measurements are studied: the precision is +-2% with a field cavity of 5 mm diameter [fr

  7. Pulse power applications of flux compression generators

    International Nuclear Information System (INIS)

    Fowler, C.M.; Caird, R.S.; Erickson, D.J.; Freeman, B.L.

    1981-01-01

    Characteristics are presented for two different types of explosive driven flux compression generators and a megavolt pulse transformer. Status reports are given for rail gun and plasma focus programs for which the generators serve as power sources

  8. Experimental and theoretical study of helical explosive electrical current generators with magnetic field compression

    International Nuclear Information System (INIS)

    Antoni, Bernard; Nazet, Christian.

    1975-07-01

    A generator of electrical energy in which magnetic field compression is achieved by a solid explosive is described. The magnetic flux losses have been calculated for generators of various configurations by the skin depth concept. Calculations take the Joule heating of conductors into account. In helical generators the magnetic flux losses are higher than those calculated by considering diffusion only. Additional losses approximately as important as diffusion losses have already been observed elsewhere on similar devices. Detailed calculations of the motion of the explosively driven inner conductor show that losses come from the jumps encountered by sliding contact moving along the helix. The jumps are caused by little geometrical defects and the consequence on losses is strongly dependent on current intensity. The jumps decrease when the pitch of helix increases. The jumps are detrimental to the efficient use of the explosive energy. With helical generators only 5% of the energy is transferred into magnetic energy [fr

  9. Analysis of non-destructive current simulators of flux compression generators.

    Science.gov (United States)

    O'Connor, K A; Curry, R D

    2014-06-01

    Development and evaluation of power conditioning systems and high power microwave components often used with flux compression generators (FCGs) requires repeated testing and characterization. In an effort to minimize the cost and time required for testing with explosive generators, non-destructive simulators of an FCG's output current have been developed. Flux compression generators and simulators of FCGs are unique pulsed power sources in that the current waveform exhibits a quasi-exponential increasing rate at which the current rises. Accurately reproducing the quasi-exponential current waveform of a FCG can be important in designing electroexplosive opening switches and other power conditioning components that are dependent on the integral of current action and the rate of energy dissipation. Three versions of FCG simulators have been developed that include an inductive network with decreasing impedance in time. A primary difference between these simulators is the voltage source driving them. It is shown that a capacitor-inductor-capacitor network driving a constant or decreasing inductive load can produce the desired high-order derivatives of the load current to replicate a quasi-exponential waveform. The operation of the FCG simulators is reviewed and described mathematically for the first time to aid in the design of new simulators. Experimental and calculated results of two recent simulators are reported with recommendations for future designs.

  10. Rail gun powered by an integral explosive generator

    International Nuclear Information System (INIS)

    Peterson, D.R.; Fowler, C.M.

    1979-01-01

    We propose the use of a rail gun powered by an explosive magnetic flux compression generator built into the rail gun itself in which the rails of the gun are driven together behind the projectile by explosives. The magnetic field established between the rails by an initial current supplied by an external source at the breech of the gun is trapped and compressed by the collapsing rails to accelerate the projectile down the bore of the gun

  11. Explosive mechanism of metal destruction by intense electromagnetic radiation flux

    International Nuclear Information System (INIS)

    Martynyuk, M.M.

    1977-01-01

    The metal destruction by a powerful flux of electromagnetic radiation is considered on the basis of thermodynamics and kinetics of the transition of molten metal to vapour during its rapid heating. The possibility is discussed of obtaining a metastable liquid-metal phase and of its explosion transition to a stable two-phase state (phase explosion of metastable liquid). It has been shown that at densities of radiation beam ensuring the heating of the metal to the spinodal point Tsub(s) during a time tsub(s)=10 -5 -10 -7 s the vaporization of the matter from the surface of the liquid is negligible, and the main mechanism of the metal destruction is the phase explosion of the metastable liquid-metal phase which originates in the Tsub(s) vicinity. The experimental data on the electric explosion of conductors for tsub(s)=10 -6 -10 -5 s has served as a basis for calculating the excess enthalpy and the proportion of the vapour phase formed in the phase explosion of Cu, Ag, Au, Zn, Cd, Al, Pb, Zr, Nb, Mo, W, Pt and Re. The particularities of the phase explosion at flux densities corresponding to tsub(s)( -8 s are considered

  12. Losses in magnetic flux compression generators: Part 2, Radiation losses

    International Nuclear Information System (INIS)

    Fowler, C.M.

    1988-06-01

    This is the second monograph devoted to the analysis of flux losses in explosive driven magnetic flux compression generators. In the first monograph, flux losses from magnetic field penetration into conductor walls was studied by conventional diffusion theory. In the present report flux loss by radiation from the outer conductor walls is treated. Flux leakage rates through walls of finite thickness are first obtained by diffusion theory. It is shown, for normal wall thicknesses, that flux leakage is determined essentially by the wall conductance, defined as the product of wall thickness and wall conductivity. This remains true when the wall thickness is reduced to zero at unchanged conductance. In this case the wall is said to be coalesced. Solutions for a cavity bounded by a perfect conductor on one side and a coalesced wall on the other are then obtained using the complete Maxwell wave equations in both the cavity and free space beyond the coalesced wall. Several anomalies, noted earlier, that arise from diffusion analysis are resolved by the wave treatment. Conditions for the validity of the diffusion treatment are noted, and an expression is obtained within the framework of diffusion theory for energy radiated into space from the cavity walls. The free space wave equations are solved by using the method of characteristics in both the cavity and free space regions. An extension of the characteristic method to situations where the constitutive relations are non-linear is outlined in an appendix. For a special class of these relations, Riemann-like invariants are determined explicitly and used to solve a particular example

  13. Sensitivity Analysis and Stray Capacitance of Helical Flux Compression Generator with Multi Layer Filamentary Conductor in Rectangular Cross-Section

    Directory of Open Access Journals (Sweden)

    M. E. Mosleh

    2012-03-01

    Full Text Available This paper presents an approach to calculate the equivalent stray capacitance (SC of n-turn of the helical flux compression generator (HFCG coil with multi layer conductor wire filaments (MLCWF in the form of rectangular cross-section. This approach is based on vespiary regular hexagonal (VRH model. In this method, wire filaments of the generator coil are separated into many very small similar elementary cells. By the expanded explosion in the liner and move explosion to the end of the liner, the coil turns number will be reduced. So, the equivalent SC of the HFCG will increase. The results show that by progress of explosion and decrease of the turns’ number in the generator coil total capacitance of the generator increases until the explosion reaches to the second turn. When only one turn remains in the circuit, a decrease occurs in the total capacitance of the generator.

  14. Plasma crowbars in cylindrical flux compression experiments

    International Nuclear Information System (INIS)

    Suter, L.J.

    1979-01-01

    We have done a series of one- and two-dimensional calculations of hard-core Z-pinch flux compression experiments in order to study the effect of a plasma on these systems. These calculations show that including a plasma can reduce the amount of flux lost during the compression. Flux losses to the outer wall of such experiments can be greatly reduced by a plasma conducting sheath which forms along the wall. This conducting sheath consists of a cold, dense high β, unmagnetized plasma which has enough pressure to balance a large field gradient. Flux which is lost into the center conductor is not effectively stopped by this plasma sheath until late in the implosion, at which time a layer similar to the one formed at the outer wall is created. Two-dimensionl simulations show that flux losses due to arching along the sliding contact of the experiment can be effectively stopped by the formation of a plasma conducting sheath

  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. Design of a spheromak compressor driven by high explosives

    International Nuclear Information System (INIS)

    Henins, I.; Fernandez, J.C.; Jarboe, T.R.; Marsh, S.P.; Marklin, G.J.; Mayo, R.M.; Wysocki, F.J.

    1990-01-01

    High energy density spheromaks can be used to accelerate a thin section of the flux conserver wall to high velocities. The energy density of a spheromak, formed by conventional helicity injection into a flux conserver, can be increased by reducing the flux conserver volume after the spheromak is formed. A method of accomplishing this is by imploding one wall of the flux conserver with high explosives. The authors have embarked on a program to demonstrate that a spheromak can be used as an energy transfer medium, and that a velocity gain over high-explosive driven plate velocities can be achieved. To do this, a plasma gun helicity source that will inject a spheromak with suitable initial energy density and lifetime is needed. Also, an implodable flux conserver that remains intact and clean during the implosion must be developed. The flux conserver problem is probably the more challenging one, because very little experimental work has been done in the past on explosively driven metal plates into a high vacuum, with sizes and travel distances appropriate for their application. There are two necessary practical requirements for an explosive compression of a flux conserver. The first is that the imploding wall does not rupture. The second is that gasses or other debri are not ejected which could penetrate and poison the spheromak plasma, and thus reduce the spheromak lifetime below what is necessary to carry out the spheromak compression and the subsequent acceleration of the flyer plate. The authors have designed and fabricated a plasma gun to be used for injecting the initial spheromak plasma into the collapsible flux conserver

  18. Quasi-isentropic compression using compressed water flow generated by underwater electrical explosion of a wire array

    Science.gov (United States)

    Gurovich, V.; Virozub, A.; Rososhek, A.; Bland, S.; Spielman, R. B.; Krasik, Ya. E.

    2018-05-01

    A major experimental research area in material equation-of-state today involves the use of off-Hugoniot measurements rather than shock experiments that give only Hugoniot data. There is a wide range of applications using quasi-isentropic compression of matter including the direct measurement of the complete isentrope of materials in a single experiment and minimizing the heating of flyer plates for high-velocity shock measurements. We propose a novel approach to generating quasi-isentropic compression of matter. Using analytical modeling and hydrodynamic simulations, we show that a working fluid composed of compressed water, generated by an underwater electrical explosion of a planar wire array, might be used to efficiently drive the quasi-isentropic compression of a copper target to pressures ˜2 × 1011 Pa without any complex target designs.

  19. Degradation of superconductivity in A15 V3Si by explosive compression

    International Nuclear Information System (INIS)

    Stewart, G.; Olinger, B.; Newkirk, L.R.

    1985-01-01

    We have found that explosive compression similar to that used to create A15 Nb 3 Si seriously degrades superconductivity in A15 V 3 Si which, before compression, was typical of well-ordered material. Specifically, the midpoint of the bulk superconducting transition is depressed by 1.8 K, the bulk transition width is increased by a factor of 3, and the specific heat γ is decreased by more than 20% compared to the starting material. Implications of these results for the ultimate achievable transition temperature in A15 Nb 3 Si are discussed

  20. 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)

  1. Flux Limiter Lattice Boltzmann for Compressible Flows

    International Nuclear Information System (INIS)

    Chen Feng; Li Yingjun; Xu Aiguo; Zhang Guangcai

    2011-01-01

    In this paper, a new flux limiter scheme with the splitting technique is successfully incorporated into a multiple-relaxation-time lattice Boltzmann (LB) model for shacked compressible flows. The proposed flux limiter scheme is efficient in decreasing the artificial oscillations and numerical diffusion around the interface. Due to the kinetic nature, some interface problems being difficult to handle at the macroscopic level can be modeled more naturally through the LB method. Numerical simulations for the Richtmyer-Meshkov instability show that with the new model the computed interfaces are smoother and more consistent with physical analysis. The growth rates of bubble and spike present a satisfying agreement with the theoretical predictions and other numerical simulations. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  2. Nuclear transmutation by flux compression

    International Nuclear Information System (INIS)

    Seifritz, W.

    2001-01-01

    A new idea for the transmutation of minor actinides, long (and even short) lived fission products is presented. It is based an the property of neutron flux compression in nuclear (fast and/or thermal) reactors possessing spatially non-stationary critical masses. An advantage factor for the burn-up fluence of the elements to be transmuted in the order of magnitude of 100 and more is obtainable compared with the classical way of transmutation. Three typical examples of such transmuters (a subcritical ringreactor with a rotating reflector, a sub-critical ring reactor with a rotating spallation source, the socalled ''pulsed energy amplifier'', and a fast burn-wave reactor) are presented and analysed with regard to this purpose. (orig.) [de

  3. The 2007 and 2014 eruptions of Stromboli at match: monitoring the potential occurrence of effusion-driven basaltic paroxysmal explosions from a volcanic CO2 flux perspective

    Science.gov (United States)

    Liuzzo, Marco; Aiuppa, Alessandro; Salerno, Giuseppe; Burton, Mike; Federico, Cinzia; Caltabiano, Tommaso; Giudice, Gaetano; Giuffrida, Giovanni

    2015-04-01

    The recent effusive unrests of Stromboli occurred in 2002 and 2007 were both punctuated by short-lived, violent paroxysmal explosions generated from the volcano's summit craters. When effusive activity recently resumed on Stromboli, on 6 August 2014, much concern was raised therefore on whether or not a paroxysm would have occurred again. The occurrence of these potentially hazardous events has stimulated research toward understanding the mechanisms through which effusive eruptions can perturb the volcano's plumbing system, to eventually trigger a paroxysm. The anomalously large CO2 gas emissions measured prior to the 15 March 2007 paroxysmal explosion of Stromboli [1] have first demonstrated the chance to predict days in advance the effusive-to-explosive transition. Here 2007 and 2014 volcanic CO2 flux records have been compared for exploring causes/conditions that had not triggered any paroxysm event in the 2014 case. We show that the 2007 and 2014 datasets shared both similarities and remarkable differences. The pre-eruptive trends of CO2 and SO2 flux emissions were strikingly similar in both 2007 and 2014, indicating similar conditions within the plumbing system prior to onset of both effusive crises. In both events, the CO2 flux substantially accelerated (relative to the pre-eruptive mean flux) after onset of the effusion. However, this CO2 flux acceleration was a factor 3 lower in 2014 than in 2007, and the excess CO2 flux (the fraction of CO2 not associated with the shallowly emplaced/erupted magma, and therefore contributed by the deep magmatic system) never returned to the very high levels observed prior to the 15 March 2007 paroxysm. We conclude therefore that, although similar quantities of magma were effusively erupted in 2007 and 2014, the deep magmatic system was far less perturbed in the most recent case. We speculate that the rate at which the deep magmatic system is decompressed, rather than the level of de-compression itself, determine if the deep

  4. Contribution to the understanding of the high magnetic field compression produced by the implosion of a thin metal tube

    International Nuclear Information System (INIS)

    Besancon, Jacques

    1970-12-01

    In this report we present the essential phenomena which occur during the magnetic flux compression obtained by the explosive-driven implosion of a thin conducting liner: acceleration time, dynamic evolution, heating and instability behaviour of the liner; field diffusion through the conducting wall and resulting flux losses which condition the increasing field in the cavity. Various implosion models are proposed and the one most elaborated leads to a numerical computation of the flux compression. Repeated experiments have permitted us to define and improve the flux injection techniques, the optical and electrical diagnostics and, consequently, the final compressed field. We now know how to obtain and record reproducible fields of 12 MOe in 0.8 cm diameter cavities. The final phase or the liner 'turnaround' has been specially observed. All the implosion shots are compared to the theoretical expectation. It may be concluded that the liner electrical conductivity and its variation essentially determine the final flux value. (author) [fr

  5. Radiographic x-ray flux monitoring during explosive experiments by copper activation

    International Nuclear Information System (INIS)

    Goosman, D.R.

    1986-01-01

    During radiographic experiments involving explosives, it is valuable to have a method of monitoring the x-ray flux ratio between the dynamic experiment and an x-ray taken of a static object for comparison. The standard method of monitoring with thermoluminescent detectors suffers the disadvantages of being sensitive to temperature, shock, uv radiation, cleanliness and saturation. A flux monitoring system is being studied which is not subject to any of the above disadvantages and is based upon the 63Cu(photon,n)62Cu reaction. The 62Cu has a 10 min half life and is counted by a nuclear pulse counting system within a few minutes of an explosive test. 170 microcoulomb of 19.3 MeV electrons hitting 1.18 mm of Ta produces x-rays which illuminate a 0.8mm thick by 1.6 cm diameter Cu disk placed 46 cm from the Ta. The activated Cu is placed in a counting system with a window between 400 to 600 keV and produces about 42,500 counts in the first 100 sec. counting period. Less than 0.2% of the initial activity is due to other reactions. Photo-induced neutrons in Be parts of the system are shown to produce a negligible effect in the Cu. The main disadvantage of the Cu activation is its sensitivity to electron energy. Monte-Carlo calculations of the excitation function for our accelerator are shown, along with excitation functions for three other configurations

  6. Radiographic x-ray flux monitoring during explosive experiments by copper activation

    International Nuclear Information System (INIS)

    Goosman, D.R.

    1986-01-01

    During radiographic experiments involving explosives, it is valuable to have a method of monitoring the X-ray flux ratio between the dynamic experiment and an X-ray taken of a static object for comparison. The standard method of monitoring with thermoluminescent detectors suffers the disadvantages of being sensitive to temperature, shock, UV radiation, cleanliness and saturation. We are studying an additional flux monitoring system which is not subject to any of the above disadvantages and is based upon the 63 Cu(photon,n) 62 Cu reaction. The 62 Cu has a 10 min. half-life and is counted by a nuclear pulse-counting system within a few minutes of an explosive test. 170 MicroCoulomb of 19.3 MeV electrons hitting 1.18mm of Ta produces X-rays which illuminate a 0.8mm thick by 1.6cm diameter Cu disk placed 46cm from the Ta. The activated Cu is placed in a counting system with a window between 400-600 keV and produces about 42500 counts in the first 100 sec counting period. Less than 0.2% of the initial activity is due to other reactions. Photo-induced neutrons in Be parts of the system are shown to produce a negligible effect in the Cu. The main disadvantage of the Cu activation is its sensitivity to electron energy. Monte-Carlo calculations of the excitation function for our accelerator are shown, along with excitation functions for three other configurations

  7. 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.

  8. 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.

  9. Analysis and modeling of flow-blockage-induced steam explosion events in the high-flux isotope reactor

    International Nuclear Information System (INIS)

    Taleyarkhan, R.P.; Georgevich, V.; Nestor, C.W.; Gat, U.; Lepard, B.L.; Cook, D.H.; Freels, J.; Chang, S.J.; Luttrell, C.; Gwaltney, R.C.

    1994-01-01

    This article provides a perspective overview of the analysis and modeling work done to evaluate the threat from steam explosion loads in the High-Flux Isotope Reactor (HFIR) during flow blockage events. The overall work scope included modeling and analysis of core-melt initiation, melt propagation, bounding and best-estimate steam explosion energetics, vessel failure from fracture, bolts failure from exceedance of elastic limits, and, finally, missile evolution and transport. Aluminum ignition was neglected. Evaluations indicated that a thermally driven steam explosion with more than 65 MJ of energy insertion in the core region over several milliseconds would be needed to cause a sufficiently energetic missile with a capacity to cause early confinement failure. This amounts to about 65% of the HFIR core mass melting and participating in a steam explosion. Conservative melt propagation analyses have indicated that at most only 24% of the HFIR core mass could melt during flow blockage events under full-power conditions. 19 refs., 11 figs

  10. Analysis and modeling of flow blockage-induced steam explosion events in the High-Flux Isotope Reactor

    International Nuclear Information System (INIS)

    Taleyarkhan, R.P.; Georgevich, V.; Lestor, C.W.; Gat, U.; Lepard, B.L.; Cook, D.H.; Freels, J.; Chang, S.J.; Luttrell, C.; Gwaltney, R.C.; Kirkpatrick, J.

    1993-01-01

    This paper provides a perspective overview of the analysis and modeling work done to evaluate the threat from steam explosion loads in the High-Flux Isotope Reactor during flow blockage events. The overall workscope included modeling and analysis of core melt initiation, melt propagation, bounding and best-estimate steam explosion energetics, vessel failure from fracture, bolts failure from exceedance of elastic limits, and finally, missile evolution and transport. Aluminum ignition was neglected. Evaluations indicated that a thermally driven steam explosion with more than 65 MJ of energy insertion in the core region over several miliseconds would be needed to cause a sufficiently energetic missile with a capacity to cause early confinement failure. This amounts to about 65% of the HFIR core mass melting and participating in a steam explosion. Conservative melt propagation analyses have indicated that at most only 24% of the HFIR core mass could melt during flow blockage events under full-power conditions. Therefore, it is judged that the HFIR vessel and top head structure will be able to withstand loads generated from thermally driven steam explosions initiated by any credible flow blockage event. A substantial margin to safety was demonstrated

  11. Explosive emission as a process involving a plasma flux

    International Nuclear Information System (INIS)

    Smirnov, B.M.

    1995-01-01

    Investigating the character of an intense emission in electric discharges, G.A. Mesyats has discovered in 1966 the phenomenon of explosive emission. This Phenomenon consists in heating of some cathode region under the influence of discharge currents. As a result, a plasm of a high conductivity is formed near the cathode, and the discharge current passes through this plasm during its existence. This phenomenon is studied in detail from different standpoints. Below we consider one more aspect of this phenomenon by using its analogy with a plasm which results fran irradiation of a surface. Estimates for a copper cathode will be made. A schematic character of the phenomenon under consideration is as follows. An electric field near a cathode creates an electric current. which is concentrated bi a small region of the cathode and heat it. Evaporating atoms with admixture of electrons and ions form a flux which is transformed to a fully ionized plasma under the influence of external fields. This plasm has a high conductivity and provides passing of electric currents of a high intensity. Note that for simplicity we omit different peculiarities of this phenomenon because here a plasma flux is of interest as a conductive matter

  12. SEED BANKS FOR MAGNETIC FLUX COMPRESSION GENERATORS

    Energy Technology Data Exchange (ETDEWEB)

    Fulkerson, E S

    2008-05-14

    In recent years the Lawrence Livermore National Laboratory (LLNL) has been conducting experiments that require pulsed high currents to be delivered into inductive loads. The loads fall into two categories (1) pulsed high field magnets and (2) the input stage of Magnetic Flux Compression Generators (MFCG). Three capacitor banks of increasing energy storage and controls sophistication have been designed and constructed to drive these loads. One bank was developed for the magnet driving application (20kV {approx} 30kJ maximum stored energy.) Two banks where constructed as MFCG seed banks (12kV {approx} 43kJ and 26kV {approx} 450kJ). This paper will describe the design of each bank including switching, controls, circuit protection and safety.

  13. ECF2: A pulsed power generator based on magnetic flux compression for K-shell radiation production

    International Nuclear Information System (INIS)

    L'Eplattenier, P.; Lassalle, F.; Mangeant, C.; Hamann, F.; Bavay, M.; Bayol, F.; Huet, D.; Morell, A.; Monjaux, P.; Avrillaud, G.; Lalle, B.

    2002-01-01

    The 3 MJ energy stored ECF2 generator is developed at Centre d'Etudes de Gramat, France, for K-shell radiation production. This generator is based on microsecond LTD stages as primary generators, and on the magnetic flux compression scheme for power amplification from the microsecond to the 100ns regime. This paper presents a general overview of the ECF2 generator. The flux compression stage, a key component, will be studied in details. We will present its advantages and drawbacks. We will then present the first experimental and numerical results which show the improvements that have already been made on this scheme

  14. Seeding magnetic fields for laser-driven flux compression in high-energy-density plasmas.

    Science.gov (United States)

    Gotchev, O V; Knauer, J P; Chang, P Y; Jang, N W; Shoup, M J; Meyerhofer, D D; Betti, R

    2009-04-01

    A compact, self-contained magnetic-seed-field generator (5 to 16 T) is the enabling technology for a novel laser-driven flux-compression scheme in laser-driven targets. A magnetized target is directly irradiated by a kilojoule or megajoule laser to compress the preseeded magnetic field to thousands of teslas. A fast (300 ns), 80 kA current pulse delivered by a portable pulsed-power system is discharged into a low-mass coil that surrounds the laser target. A >15 T target field has been demonstrated using a hot spot of a compressed target. This can lead to the ignition of massive shells imploded with low velocity-a way of reaching higher gains than is possible with conventional ICF.

  15. Small compression modulus of the flux line lattice and large density fluctuations at high fields may explain peak effect

    International Nuclear Information System (INIS)

    Brandt, E.H.

    1976-01-01

    The elastic properties of the flux line lattice in Type II superconductors as calculated from the Ginsburg-Landau theory are discussed. They are non-local on a length scale much larger than the flux line distance and divergent at Hsub(c2). The compression modulus may become much smaller than its long-wavelength limit, B 2 /4π, and if the deformation is not homogeneous, at Hsub(c2) the modulus vanishes as (Hsub(c2) - B) 2 . At arbitrary induction the compression modulus of strain waves with wavelengths of several flux line distances is of the order of the (small) shear modulus. (author)

  16. Implementing and diagnosing magnetic flux compression on the Z pulsed power accelerator

    Energy Technology Data Exchange (ETDEWEB)

    McBride, Ryan D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bliss, David E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gomez, Matthew R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hansen, Stephanie B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Martin, Matthew R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jennings, Christopher Ashley [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Slutz, Stephen A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rovang, Dean C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Knapp, Patrick F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Schmit, Paul F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Awe, Thomas James [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hess, M. H. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lemke, Raymond W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Dolan, D. H. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lamppa, Derek C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jobe, Marc Ronald Lee [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Fang, Lu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hahn, Kelly D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Chandler, Gordon A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Cooper, Gary Wayne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ruiz, Carlos L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Maurer, A. J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Robertson, Grafton Kincannon [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Cuneo, Michael E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sinars, Daniel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tomlinson, Kurt [General Atomics, San Diego, CA (United States); Smith, Gary [General Atomics, San Diego, CA (United States); Paguio, Reny [General Atomics, San Diego, CA (United States); Intrator, Tom [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Weber, Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Greenly, John [Cornell Univ., Ithaca, NY (United States)

    2015-11-01

    We report on the progress made to date for a Laboratory Directed Research and Development (LDRD) project aimed at diagnosing magnetic flux compression on the Z pulsed-power accelerator (0-20 MA in 100 ns). Each experiment consisted of an initially solid Be or Al liner (cylindrical tube), which was imploded using the Z accelerator's drive current (0-20 MA in 100 ns). The imploding liner compresses a 10-T axial seed field, B z ( 0 ) , supplied by an independently driven Helmholtz coil pair. Assuming perfect flux conservation, the axial field amplification should be well described by B z ( t ) = B z ( 0 ) x [ R ( 0 ) / R ( t )] 2 , where R is the liner's inner surface radius. With perfect flux conservation, B z ( t ) and dB z / dt values exceeding 10 4 T and 10 12 T/s, respectively, are expected. These large values, the diminishing liner volume, and the harsh environment on Z, make it particularly challenging to measure these fields. We report on our latest efforts to do so using three primary techniques: (1) micro B-dot probes to measure the fringe fields associated with flux compression, (2) streaked visible Zeeman absorption spectroscopy, and (3) fiber-based Faraday rotation. We also mention two new techniques that make use of the neutron diagnostics suite on Z. These techniques were not developed under this LDRD, but they could influence how we prioritize our efforts to diagnose magnetic flux compression on Z in the future. The first technique is based on the yield ratio of secondary DT to primary DD reactions. The second technique makes use of the secondary DT neutron time-of-flight energy spectra. Both of these techniques have been used successfully to infer the degree of magnetization at stagnation in fully integrated Magnetized Liner Inertial Fusion (MagLIF) experiments on Z [P. F. Schmit et al. , Phys. Rev. Lett. 113 , 155004 (2014); P. F. Knapp et al. , Phys. Plasmas, 22 , 056312 (2015)]. Finally, we present some recent developments for designing

  17. In Situ Imaging during Compression of Plastic Bonded Explosives for Damage Modeling

    Directory of Open Access Journals (Sweden)

    Virginia W. Manner

    2017-06-01

    Full Text Available The microstructure of plastic bonded explosives (PBXs is known to influence behavior during mechanical deformation, but characterizing the microstructure can be challenging. For example, the explosive crystals and binder in formulations such as PBX 9501 do not have sufficient X-ray contrast to obtain three-dimensional data by in situ, absorption contrast imaging. To address this difficulty, we have formulated a series of PBXs using octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX crystals and low-density binder systems. The binders were hydroxyl-terminated polybutadiene (HTPB or glycidyl azide polymer (GAP cured with a commercial blend of acrylic monomers/oligomers. The binder density is approximately half of the HMX, allowing for excellent contrast using in situ X-ray computed tomography (CT imaging. The samples were imaged during unaxial compression using micro-scale CT in an interrupted in situ modality. The rigidity of the binder was observed to significantly influence fracture, crystal-binder delamination, and flow. Additionally, 2D slices from the segmented 3D images were meshed for finite element simulation of the mesoscale response. At low stiffness, the binder and crystal do not delaminate and the crystals move with the material flow; at high stiffness, marked delamination is noted between the crystals and the binder, leading to very different mechanical properties. Initial model results exhibit qualitatively similar delamination.

  18. Compressed magnetic flux amplifier with capacitive load

    International Nuclear Information System (INIS)

    Stuetzer, O.M.

    1980-03-01

    A first-order analysis is presented for a compressed magnetic flux (CMF) current amplifier working into a load with a capacitive component. Since the purpose of the investigation was to gain a general understanding of the arrangement, a number of approximations and limitations were accepted. The inductance of the transducer varies with time; the inductance/resistance/capacitance (LRC) circuit therefore is parametric and solutions are different for the stable regime (high C), the oscillation regime (low C), and the transition case. Solutions and performance depend strongly on circuit boundary conditions, i.e., energization of the circuit by either an injected current or by an applied capacitor charge. The behavior of current and energy amplification for the various cases are discussed in detail. A number of experiments with small CMF devices showed that the first-order theory presented predicts transducer performance well in the linear regime

  19. Degassing vs. eruptive styles at Mt. Etna volcano (Sicily, Italy): Volatile stocking, gas fluxing, and the shift from low-energy to highly-explosive basaltic eruptions

    Science.gov (United States)

    Moretti, Roberto; Métrich, Nicole; Di Renzo, Valeria; Aiuppa, Alessandro; Allard, Patrick; Arienzo, Ilenia

    2017-04-01

    Basaltic magmas can transport and release large amounts of volatiles into the atmosphere, especially in subduction zones, where slab-derived fluids enrich the mantle wedge. Depending on magma volatile content, basaltic volcanoes thus display a wide spectrum of eruptive styles, from common Strombolian-type activity to Plinian events. Mt. Etna in Sicily, is a typical basaltic volcano where the volatile control on such a variable activity can be investigated. Based on a melt inclusion study in products from Strombolian or lava-fountain activity to Plinian eruptions, here we show that for the same initial volatile content, different eruptive styles reflect variable degassing paths throughout the composite Etnean plumbing system. The combined influence of i) crystallization, ii) deep degassing and iii) CO2 gas fluxing can explain the evolution of H2O, CO2, S and Cl in products from such a spectrum of activity. Deep crystallization produces the CO2-rich gas fluxing the upward magma portions, which will become buoyant and easily mobilized in small gas-rich batches stored within the plumbing system. When reaching gas dominated conditions (i.e., a gas/melt mass ratio of 0.3 and CO2,gas/H2Ogas molar ratio 5 ), these will erupt effusively or mildly explosively, whilst in case of the 122 BC Plinian eruption, open-system degassing conditions took place within the plumbing system, such that continuous CO2-fluxing determined gas accumulation on top of the magmatic system. The emission of such a cap in the early eruptive phase triggered the arrival of deep H2O-rich whose fast decompression and bubble nucleation lead to the highly explosive character, enhanced by abundant microlite crystallization and consequent increase of magma effective viscosity. This could explain why open system basaltic systems like Etna may experience highly explosive or even Plinian episodes during eruptions that start with effusive to mildly explosive phases. The proposed mechanism also determines a

  20. 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

  1. Evaluation of the US Army Research Laboratory Squeeze 5 Magnetic Flux Compression Generator

    Science.gov (United States)

    2016-09-01

    armature cracking, high-voltage insulation , and electrical arcing. 15. SUBJECT TERMS magnetic flux compression, field diffusion, mega ampere, high... insulation and can result in arcing that robs energy from the system. Magnetic field diffusion into the conducting portions of the system can also play a...indicates a short circuit occurred internally to the device, most likely due to damaged insulation during construction. The high-voltage switch failed to

  2. The Ranchero explosive pulsed power system

    International Nuclear Information System (INIS)

    Goforth, J.H.; Atchison, W.L.; Bartram, D.E.

    1997-01-01

    The authors are currently developing a high explosive pulsed power system concept that they call Ranchero. Ranchero systems consist of series-parallel combinations of simultaneously initiated coaxial magnetic flux compression generators, and are intended to operate in the range from 50 MA to a few hundred MA currents. One example of a Ranchero system is shown here. The coaxial modules lend themselves to extracting the current output either from one end or along the generator midplane. They have previously published design considerations related to the different module configurations, and in this paper they concentrate on the system that they will use for their first imploding liner tests. A single module with end output. The module is 1.4-m long and expands the armature by a factor of two to reach the 30-cm OD stator. The first heavy liner implosion experiments will be conducted in the range of 40--50 MA currents. Electrical tests, to date, have employed high explosive (HE) charges 43-cm long. They have performed tests and related 1D MHD calculations at the 45-MA current level with small loads. From these results, they determine that they can deliver currents of approximately 50 MA to loads of 8 nH

  3. Explosives disposal demonstration projects. Progress report, April 12, 1995--June 30, 1995

    International Nuclear Information System (INIS)

    Charbeneau, R.

    1995-01-01

    This report contains quarterly reports on two projects. The first is undertaking the environmental restoration at the Pantex Plant. Research objectives are organized under four general tasks: field testing and produced water treatment, bioremediation of contaminated groundwater and soils, vadose zone remediation, and chromium remediation. The other project goal is to demonstrate generation of diamond by explosive compression of Carbon 60 and Carbon 70 and mixtures of these fullerenes. The intent is to exploit expertise developed by Pantex and other DOE Laboratories in the area of understanding and modeling of explosive compression for initiation of nuclear fission reactions to explosively compress carbon in the form of fullerenes with the goal of transforming the material into the diamond phase

  4. 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.

  5. 29 CFR 1926.913 - Blasting in excavation work under compressed air.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Blasting in excavation work under compressed air. 1926.913... Use of Explosives § 1926.913 Blasting in excavation work under compressed air. (a) Detonators and... connecting wires are connected up. (b) When detonators or explosives are brought into an air lock, no...

  6. β-distribution for Reynolds stress and turbulent heat flux in relaxation turbulent boundary layer of compression ramp

    Science.gov (United States)

    Hu, YanChao; Bi, WeiTao; Li, ShiYao; She, ZhenSu

    2017-12-01

    A challenge in the study of turbulent boundary layers (TBLs) is to understand the non-equilibrium relaxation process after sep-aration and reattachment due to shock-wave/boundary-layer interaction. The classical boundary layer theory cannot deal with the strong adverse pressure gradient, and hence, the computational modeling of this process remains inaccurate. Here, we report the direct numerical simulation results of the relaxation TBL behind a compression ramp, which reveal the presence of intense large-scale eddies, with significantly enhanced Reynolds stress and turbulent heat flux. A crucial finding is that the wall-normal profiles of the excess Reynolds stress and turbulent heat flux obey a β-distribution, which is a product of two power laws with respect to the wall-normal distances from the wall and from the boundary layer edge. In addition, the streamwise decays of the excess Reynolds stress and turbulent heat flux also exhibit power laws with respect to the streamwise distance from the corner of the compression ramp. These results suggest that the relaxation TBL obeys the dilation symmetry, which is a specific form of self-organization in this complex non-equilibrium flow. The β-distribution yields important hints for the development of a turbulence model.

  7. Adiabatic compression and radiative compression of magnetic fields

    International Nuclear Information System (INIS)

    Woods, C.H.

    1980-01-01

    Flux is conserved during mechanical compression of magnetic fields for both nonrelativistic and relativistic compressors. However, the relativistic compressor generates radiation, which can carry up to twice the energy content of the magnetic field compressed adiabatically. The radiation may be either confined or allowed to escape

  8. Electric-gun studies of conductors in high magnetic fields and experiments in dynamic flux compression

    International Nuclear Information System (INIS)

    Osher, J.E.; Chau, H.H.; Lee, R.S.; Tipton, R.E.; Weingart, R.C.

    1990-01-01

    Electric guns operate by discharging a fast capacitor bank through a thin, metallic bridge-foil load. The explosion of the foil and the accompanying magnetic forces acting on the bridge-foil plasma accelerate a thin flyer plate of dielectric material initially placed on top of the bridge foil. In hypervelocity impact studies with the linear electric gun, a thin, flat flyer is punched out of a cover sheet of dielectric (or dielectric/metallic composite) material by the explosion of the bridge foil and accelerated down a short barrel to impact on a target. In the coaxial gun, a cylindrical bridge foil is used to implode a cylindrical dielectric or dielectric/metallic composite (liner) flyer to produce a high peak compression through axial convergence. In this paper the authors discuss the range of currents, their rate of rise, and the magnetic fields attained by their fast capacitor banks, which supply power to the electric gun to explode the bridge foil. Also included is a study of the change of resistance of the bridge-foil element as a function of time for various flyer mass loadings for the linear geometry of the gun

  9. A robust and accurate approach to computing compressible multiphase flow: Stratified flow model and AUSM+-up scheme

    International Nuclear Information System (INIS)

    Chang, Chih-Hao; Liou, Meng-Sing

    2007-01-01

    In this paper, we propose a new approach to compute compressible multifluid equations. Firstly, a single-pressure compressible multifluid model based on the stratified flow model is proposed. The stratified flow model, which defines different fluids in separated regions, is shown to be amenable to the finite volume method. We can apply the conservation law to each subregion and obtain a set of balance equations. Secondly, the AUSM + scheme, which is originally designed for the compressible gas flow, is extended to solve compressible liquid flows. By introducing additional dissipation terms into the numerical flux, the new scheme, called AUSM + -up, can be applied to both liquid and gas flows. Thirdly, the contribution to the numerical flux due to interactions between different phases is taken into account and solved by the exact Riemann solver. We will show that the proposed approach yields an accurate and robust method for computing compressible multiphase flows involving discontinuities, such as shock waves and fluid interfaces. Several one-dimensional test problems are used to demonstrate the capability of our method, including the Ransom's water faucet problem and the air-water shock tube problem. Finally, several two dimensional problems will show the capability to capture enormous details and complicated wave patterns in flows having large disparities in the fluid density and velocities, such as interactions between water shock wave and air bubble, between air shock wave and water column(s), and underwater explosion

  10. Comprehensive Characterization of Voids and Microstructure in TATB-based Explosives from 10 nm to 1 cm: Effects of Temperature Cycling and Compressive Creep

    Energy Technology Data Exchange (ETDEWEB)

    Willey, T M; Lauderbach, L; Gagliardi, F; Cunningham, B; Lorenz, K T; Lee, J I; van Buuren, T; Call, R; Landt, L; Overturf, G

    2010-02-26

    This paper outlines the characterization of voids and Microstructure in TATB-based Explosives over several orders of magnitude, from sizes on the order of 10 nm to about 1 cm. This is accomplished using ultra small angle x-ray scattering to investigate voids from a few nm to a few microns, ultra small angle neutron scattering for voids from 100 nm to 10 microns, and x-ray computed microtomography to investigate microstructure from a few microns to a few centimeters. The void distributions of LX-17 are outlined, and the microstructure of LX-17 is presented. Temperature cycling and compressive creep cause drastically different damage to the microstructure. Temperature cycling leads to a volume expansion (ratchet growth) in TATB-based explosives, and x-ray scattering techniques that are sensitive to sizes up to a few microns indicated changes to the void volume distribution that had previously accounted for most, but not all of the change in density. This paper presents the microstructural damage larger than a few microns caused by ratchet growth. Temperature cycling leads to void creation in the binder poor regions associated with the interior portion of formulated prills. Conversely, compressive creep causes characteristically different changes to microstructure; fissures form at binder-rich prill boundaries prior to mechanical failure.

  11. 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

  12. Tokamak plasma variations under rapid compression

    International Nuclear Information System (INIS)

    Holmes, J.A.; Peng, Y.K.M.; Lynch, S.J.

    1980-04-01

    Changes in plasmas undergoing large, rapid compressions are examined numerically over the following range of aspect ratios A:3 greater than or equal to A greater than or equal to 1.5 for major radius compressions of circular, elliptical, and D-shaped cross sections; and 3 less than or equal to A less than or equal to 6 for minor radius compressions of circular and D-shaped cross sections. The numerical approach combines the computation of fixed boundary MHD equilibria with single-fluid, flux-surface-averaged energy balance, particle balance, and magnetic flux diffusion equations. It is found that the dependences of plasma current I/sub p/ and poloidal beta anti β/sub p/ on the compression ratio C differ significantly in major radius compressions from those proposed by Furth and Yoshikawa. The present interpretation is that compression to small A dramatically increases the plasma current, which lowers anti β/sub p/ and makes the plasma more paramagnetic. Despite large values of toroidal beta anti β/sub T/ (greater than or equal to 30% with q/sub axis/ approx. = 1, q/sub edge/ approx. = 3), this tends to concentrate more toroidal flux near the magnetic axis, which means that a reduced minor radius is required to preserve the continuity of the toroidal flux function F at the plasma edge. Minor radius compressions to large aspect ratio agree well with the Furth-Yoshikawa scaling laws

  13. A Novel A Posteriori Investigation of Scalar Flux Models for Passive Scalar Dispersion in Compressible Boundary Layer Flows

    Science.gov (United States)

    Braman, Kalen; Raman, Venkat

    2011-11-01

    A novel direct numerical simulation (DNS) based a posteriori technique has been developed to investigate scalar transport modeling error. The methodology is used to test Reynolds-averaged Navier-Stokes turbulent scalar flux models for compressible boundary layer flows. Time-averaged DNS velocity and turbulence fields provide the information necessary to evolve the time-averaged scalar transport equation without requiring the use of turbulence modeling. With this technique, passive dispersion of a scalar from a boundary layer surface in a supersonic flow is studied with scalar flux modeling error isolated from any flowfield modeling errors. Several different scalar flux models are used. It is seen that the simple gradient diffusion model overpredicts scalar dispersion, while anisotropic scalar flux models underpredict dispersion. Further, the use of more complex models does not necessarily guarantee an increase in predictive accuracy, indicating that key physics is missing from existing models. Using comparisons of both a priori and a posteriori scalar flux evaluations with DNS data, the main modeling shortcomings are identified. Results will be presented for different boundary layer conditions.

  14. 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

  15. Spherical Solutions of an Underwater Explosion Bubble

    Directory of Open Access Journals (Sweden)

    Andrew B. Wardlaw

    1998-01-01

    Full Text Available The evolution of the 1D explosion bubble flow field out to the first bubble minimum is examined in detail using four different models. The most detailed is based on the Euler equations and accounts for the internal bubble fluid motion, while the simplest links a potential water solution to a stationary, Isentropic bubble model. Comparison of the different models with experimental data provides insight into the influence of compressibility and internal bubble dynamics on the behavior of the explosion bubble.

  16. FRC translation into a compression coil

    International Nuclear Information System (INIS)

    Chrien, R.E.

    1986-01-01

    The equilibrium and translational kinematics of Field-Reversed Configurations (FRCs) in a cylindrical coil which does not conserve flux are problems that arise in connection with adiabatic compressional heating. In this paper, they consider several features of the problem of FRC translation into a compression coil. First, the magnitude of the guide field is calculated and found to exceed that which would be applied to a flux conserver. Second, energy conservation is applied to FRC translation from a flux conserver into a compression coil. It is found that a significant temperature decrease is required for translation to be energetically possible. The temperature change depends on the external inductance in the compression circuit. An analogous case is that of a compression region composed of a compound magnet; in this case the temperature change depends on the ratio of inner and outer coil radii. Finally, the kinematics of intermediate translation states are calculated using an abrupt transition model. It is found, in this model, that the FRC must overcome a potential hill during translation, which requires a small initial velocity

  17. Circular, explosion-proof lamp provides uniform illumination

    Science.gov (United States)

    1966-01-01

    Circular explosion-proof fluorescent lamp is fitted around a TV camera lens to provide shadowless illumination with a low radiant heat flux. The lamp is mounted in a transparent acrylic housing sealed with clear silicone rubber.

  18. 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.

  19. Compression of pulsed electron beams for material tests

    Science.gov (United States)

    Metel, Alexander S.

    2018-03-01

    In order to strengthen the surface of machine parts and investigate behavior of their materials exposed to highly dense energy fluxes an electron gun has been developed, which produces the pulsed beams of electrons with the energy up to 300 keV and the current up to 250 A at the pulse width of 100-200 µs. Electrons are extracted into the accelerating gap from the hollow cathode glow discharge plasma through a flat or a spherical grid. The flat grid produces 16-cm-diameter beams with the density of transported per one pulse energy not exceeding 15 J·cm-2, which is not enough even for the surface hardening. The spherical grid enables compression of the beams and regulation of the energy density from 15 J·cm-2 up to 15 kJ·cm-2, thus allowing hardening, pulsed melting of the machine part surface with the further high-speed recrystallization as well as an explosive ablation of the surface layer.

  20. GRAVITATIONAL FIELD SHIELDING AND SUPERNOVA EXPLOSIONS

    International Nuclear Information System (INIS)

    Zhang, T. X.

    2010-01-01

    A new mechanism for supernova explosions called gravitational field shielding is proposed, in accord with a five-dimensional fully covariant Kaluza-Klein theory with a scalar field that unifies the four-dimensional Einsteinian general relativity and Maxwellian electromagnetic theory. It is shown that a dense compact collapsing core of a star will suddenly turn off or completely shield its gravitational field when the core collapses to a critical density, which is inversely proportional to the square of mass of the core. As the core suddenly turns off its gravity, the extremely large pressure immediately stops the core collapse and pushes the mantle material of supernova moving outward. The work done by the pressure in the expansion can be the order of energy released in a supernova explosion. The gravity will resume and stop the core from a further expansion when the core density becomes less than the critical density. Therefore, the gravitational field shielding leads a supernova to impulsively explode and form a compact object such as a neutron star as a remnant. It works such that a compressed spring will shoot the oscillator out when the compressed force is suddenly removed.

  1. Degassing Processes at Persistently Active Explosive Volcanoes

    Science.gov (United States)

    Smekens, Jean-Francois

    Among volcanic gases, sulfur dioxide (SO2) is by far the most commonly measured. More than a monitoring proxy for volcanic degassing, SO 2 has the potential to alter climate patterns. Persistently active explosive volcanoes are characterized by short explosive bursts, which often occur at periodic intervals numerous times per day, spanning years to decades. SO 2 emissions at those volcanoes are poorly constrained, in large part because the current satellite monitoring techniques are unable to detect or quantify plumes of low concentration in the troposphere. Eruption plumes also often show high concentrations of ash and/or aerosols, which further inhibit the detection methods. In this work I focus on quantifying volcanic gas emissions at persistently active explosive volcanoes and their variations over short timescales (minutes to hours), in order to document their contribution to natural SO2 flux as well as investigate the physical processes that control their behavior. In order to make these measurements, I first develop and assemble a UV ground-based instrument, and validate it against an independently measured source of SO2 at a coal-burning power plant in Arizona. I establish a measurement protocol and demonstrate that the instrument measures SO 2 fluxes with Indonesia), a volcano that has been producing cycles of repeated explosions with periods of minutes to hours for the past several decades. Semeru produces an average of 21-71 tons of SO2 per day, amounting to a yearly output of 8-26 Mt. Using the Semeru data, along with a 1-D transient numerical model of magma ascent, I test the validity of a model in which a viscous plug at the top of the conduit produces cycles of eruption and gas release. I find that it can be a valid hypothesis to explain the observed patterns of degassing at Semeru. Periodic behavior in such a system occurs for a very narrow range of conditions, for which the mass balance between magma flux and open-system gas escape repeatedly

  2. FRC translation into a compression coil

    International Nuclear Information System (INIS)

    Chrien, R.E.

    1985-01-01

    Several features of the problem of FRC translation into a compression coil are considered. First, the magnitude of the guide field is calculated and found to exceed that which would be applied to a flux conserver. Second, energy conservation is applied to FRC translation from a flux conserver into a compression coil. It is found that a significant temperature decrease is required for translation to be energetically possible. The temperature change depends on the external inductance in the compression circuit. An analogous case is that of a compression region composed of a compound magnet; in this case the temperature change depends on the ratio of inner and outer coil radii. Finally, the kinematics of intermediate translation states are calculated using an ''abrupt transition'' model. It is found, in this model, that the FRC must overcome a potential hill during translation, which requires a small initial velocity

  3. P. W. Bridgman's contributions to the foundations of shock compression of condensed matter

    Energy Technology Data Exchange (ETDEWEB)

    Nellis, W J, E-mail: nellis@physics.harvard.ed [Department of Physics, Harvard University, Cambridge MA 02138 (United States)

    2010-03-01

    Based on his 50-year career in static high-pressure research, P. W. Bridgman (PWB) is the father of modern high-pressure physics. What is not generally recognized is that Bridgman was also intimately connected with establishing shock compression as a scientific tool and he predicted major events in shock research that occurred up to 40 years after his death. In 1956 the first phase transition under shock compression was reported in Fe at 13 GPa (130 kbar). PWB said a phase transition could not occur in a {approx}microsec, thus setting off a controversy. The scientific legitimacy of shock compression resulted 5 years later when static high-pressure researchers confirmed with x-ray diffraction the existence of epsilon-Fe. Once PWB accepted the fact that shock waves generated with chemical explosives were a valid scientific tool, he immediately realized that substantially higher pressures would be achieved with nuclear explosives. He included his ideas for achieving higher pressures in articles published a few years after his death. L. V. Altshuler eventually read Bridgman's articles and pursued the idea of using nuclear explosives to generate super high pressures, which subsequently morphed today into giant lasers. PWB also anticipated combining static and shock methods, which today is done with pre-compression of a soft sample in a diamond anvil cell followed by laser-driven shock compression. One variation of that method is the reverberating-shock technique, in which the first shock pre-compresses a soft sample and subsequent reverberations isentropically compress the first-shocked state.

  4. High-explosive-driven delay line pulse generator

    International Nuclear Information System (INIS)

    Shearer, J.W.

    1982-01-01

    The inclusion of a delay line circuit into the design of a high-explosive-driven generator shortens the time constant of the output pulse. After a brief review of generator concepts and previously described pulse-shortening methods, a geometry is presented which incorporates delay line circuit techcniques into a coil generator. The circuit constants are adjusted to match the velocity of the generated electromagnetic wave to the detonation velocity of the high explosive. The proposed generator can be modeled by adding a variable inductance term to the telegrapher's equation. A particular solution of this equation is useful for exploring the operational parameters of the generator. The duration of the electromagnetic pulse equals the radial expansion time of the high-explosive-driven armature until it strikes the coil. Because the impedance of the generator is a constant, the current multiplication factor is limited only by nonlinear effects such as voltage breakdown, diffusion, and compression at high energies

  5. High-temperature explosive development for geothermal well stimulation. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, E.W.; Mars, J.E.; Wang, C.

    1978-03-31

    A two-component, temperature-resistant liquid explosive called HITEX has been developed which is capable of withstanding 561/sup 0/K (550/sup 0/F) for 24 hours in a geothermal environment. The explosive is intended for the stimulation of nonproducing or marginally producing geothermal (hot dry rock, vapor-dominated or hydrothermal) reservoirs by fracturing the strata in the vicinity of a borehole. The explosive is inherently safe because it is mixed below ground downhole from two nondetonable liquid components. Development and safety tests included differential scanning calorimetry, thermal stability, minerals compatibility, drop-weight sensitivity, adiabatic compression, electrostatic discharge sensitivity, friction sensitivity, detonation arrest capability, cook-off tests, detonability at ambient and elevated pressure, detonation velocity and thin film propagation in a wedge.

  6. Energy dissipation during an explosion in a porous elasto-plastic medium

    Energy Technology Data Exchange (ETDEWEB)

    Lovetskii, E.E.; Maslennikov, A.M.; Fetisov, V.S.

    1979-01-01

    A study is made of the redistribution of energy from camouflage blasting in a saturated porous medium. The study is undertaken with the aid of a numerical solution to a system of hydrodynamic equations, that account for shear strength of the substance under investigation. A study is made of the energy characteristics of explosion, their dynamic development, the influence of strength parameters of the medium, and porosity on these characteristics. A mechanism that is associated with the impact compression of matter is identified as the basic mechanism of energy dissipation for dry porous media. Water saturation of pores brings the energy characteristics of the explosion close to the explosion in a monolith. 12 references, 5 figures, 1 table.

  7. Deflagration explosion of an unconfined fuel vapor cloud

    International Nuclear Information System (INIS)

    Taki, S.; Ogawa, Y.

    1981-01-01

    In the reported study, explosions are produced by injecting a small amount of liquefied petroleum gas (LPG) into air. The ignition and subsequent evolution of the explosion of the unconfined vapor cloud are observed by the simultaneous use of direct photographs and pressure recording. The intensity of the compression waves generated by unconfined combustion are modeled on the basis of the solution of the conservation equations for the flow associated with a spherically symmetric expanding piston. The obtained results are compared with the measurements. It is pointed out that the development of unconfined fuel vapor cloud explosions can be divided into two stages, including a deflagration propagating in premixed gases, which is followed by a diffusion flame promoted by buoyancy and convection. The experimental result from the pressure measurement is found to be quantitatively consistent with the result obtained from the spherical piston model

  8. A model of vulcanian explosions

    International Nuclear Information System (INIS)

    Woods, A.W.

    1995-01-01

    We present a model of the initial stages of the explosive eruption of magma from a volcanic conduit as occurs in Vulcanian style eruptions. We assume there is a volatile rich (1-10 wt%) mixture of magma, vaporised groundwater and exsolved volatiles, trapped at high pressure (1-100 atm) just below a plug in a volcanic conduit. If the plug disrupts, there is an explosive eruption in which a rarefaction wave propagates into the conduit allowing the volatile rich mixture to expand and discharge into the atmosphere ahead of the vent. Typically, the explosions are so rapid that coarse grained ejecta (>0.5 mm) do not remain in thermal equilibrium with the gas, and this leads to significantly lower velocities and temperatures than predicted by an equilibrium model. Material may erupt from the vent at speeds of 100-400 m s -1 with an initial mass flux of order 10 7 -10 9 kg s -1 , consistent with video observations of eruptions and measurements of the ballistic dispersal of large clasts. (orig.)

  9. Ohmic ignition of Neo-Alcator tokamak with adiabatic compression

    International Nuclear Information System (INIS)

    Inoue, Nobuyuki; Ogawa, Yuichi

    1992-01-01

    Ohmic ignition condition on axis of the DT tokamak plasma heated by minor radius and major radius adiabatic compression is studied assuming parabolic profiles for plasma parameters, elliptic plasma cross section, and Neo-Alcator confinement scaling. It is noticeable that magnetic compression reduces the necessary total plasma current for Ohmic ignition device. Typically in compact ignition tokamak of the minor radius of 0.47 m, major radius of 1.5 m and on-axis toroidal field of 20 T, the plasma current of 6.8 MA is sufficient for compression plasma, while that of 11.7 MA is for no compression plasma. Another example with larger major radius is also described. In such a device the large flux swing of Ohmic transformer is available for long burn. Application of magnetic compression saves the flux swing and thereby extends the burn time. (author)

  10. Study of the initiation and the escalade phases of a vapour explosion; Etude de la phase d'initiation et d'escalade d'une explosion de vapeur

    Energy Technology Data Exchange (ETDEWEB)

    Lamome, J

    2007-09-15

    The steam explosion triggering issue is discussed here by studying at the thermal fragmentation (small pressure perturbation) of a hot water droplet surrounded by a stable steam film. Fragmentation seems to be the consequence of local contacts between the droplet and the coolant. However, the exact mechanism altering the droplet following the above mentioned contacts is uncertain. After a study of the proportions in place, we realized a contact can fragment the droplet in a very short period of time. Therefore, we adopted an approach considering the contact as the explosion criteria. In order to validate this approach, we researched the explosion levels of the experimental variations based on the surrounding pressure and on the coolant's temperature. The model found again the experimental variations, the levels were found again with some uncertainty. The contact is obtained by 2 mechanisms inducing liquid's proximity: a steam film global compression due to the disturbance and the amplification of the interface defaults between the coolant and the steam. It appears it is the mechanism of global compression that explains mostly the experimental variations. Following these results, we conducted model's extrapolations in order to come as close as possible of the conditions in which steam explosion can occur on an industrial scale (i.e. in the water pressured nuclear reactors). (author)

  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. Design and testing of high-pressure railguns and projectiles

    International Nuclear Information System (INIS)

    Peterson, D.R.; Fowler, C.M.

    1984-01-01

    The results of high-pressure tests of four railgun designs and four projectile types are presented. All tests were conducted at the Los Alamos explosive magnetic-flux compression facility in Ancho Canyon. The data suggest that the high-strength projectiles have lower resistance to acceleration than the low strength projectiles, which expand against the bore during acceleration. The railguns were powered by explosive magneticflux compression generators. Calculations to predict railgun and power supply performance were performed by Kerrisk

  13. Cavities produced by underground nuclear explosions

    International Nuclear Information System (INIS)

    Butkovich, T.R.

    1976-01-01

    This investigation studied the displacement of rock that formerly occupied cavities produced by underground nuclear explosions. There are three possible explanations for this displacement: the volume could be displaced to the free surface; it could occupy previously air-filled pores removed from the surrounding rock through compaction; or it could be accounted for by persisting compressive stresses induced by the outgoing shock wave. The analysis shows it unlikely that stored residual elastic stresses account for large fractions of cavity volumes. There is limited experimental evidence that free surface displacement accounts for a significant portion of this volume. Whenever the explosion mediums contain air-filled pores, the compaction of these pores most likely accounts for all the volume. Calculations show that 4 percent air-filled porosity can account for all the cavity volume within about 4 cavity radii and that even 1 percent can account for a significant fraction of the volume

  14. Summary of USSR reports on mechanical and radioactivity effects of underground nuclear explosions

    Energy Technology Data Exchange (ETDEWEB)

    Kruger, Paul [Civil Engineering Department, Stanford University, Stanford, CA (United States)

    1970-05-01

    Two reports have been issued by the USSR which examine the mechanical effects and radioactive contamination of the environment from underground nuclear explosions. In reviewing the mechanical effects, the institute of Terrestrial Physics of the USSR Academy of Sciences emphasizes the advantages of nuclear explosives, namely the tremendous power and small dimensions, in the industrial and construction fields. The authors note that the mechanical effects are based not only upon the explosive yield but also upon the thermodynamic properties of the cavity gases during expansion. These properties may vary widely depending upon the rock material. A list of the basic parameters affecting the mechanical effects of contained nuclear explosions includes: cavity volume, dimensions of the chimney, degree of rock fracturing, intensity of the compression wave as a function of distance from shot point, and seismic effects. The second paper describes the phenomenology of radioactive contamination of the environment for both contained and excavation explosions.

  15. Summary of USSR reports on mechanical and radioactivity effects of underground nuclear explosions

    International Nuclear Information System (INIS)

    Kruger, Paul

    1970-01-01

    Two reports have been issued by the USSR which examine the mechanical effects and radioactive contamination of the environment from underground nuclear explosions. In reviewing the mechanical effects, the institute of Terrestrial Physics of the USSR Academy of Sciences emphasizes the advantages of nuclear explosives, namely the tremendous power and small dimensions, in the industrial and construction fields. The authors note that the mechanical effects are based not only upon the explosive yield but also upon the thermodynamic properties of the cavity gases during expansion. These properties may vary widely depending upon the rock material. A list of the basic parameters affecting the mechanical effects of contained nuclear explosions includes: cavity volume, dimensions of the chimney, degree of rock fracturing, intensity of the compression wave as a function of distance from shot point, and seismic effects. The second paper describes the phenomenology of radioactive contamination of the environment for both contained and excavation explosions

  16. Magnetic Compression Experiment at General Fusion with Simulation Results

    Science.gov (United States)

    Dunlea, Carl; Khalzov, Ivan; Hirose, Akira; Xiao, Chijin; Fusion Team, General

    2017-10-01

    The magnetic compression experiment at GF was a repetitive non-destructive test to study plasma physics applicable to Magnetic Target Fusion compression. A spheromak compact torus (CT) is formed with a co-axial gun into a containment region with an hour-glass shaped inner flux conserver, and an insulating outer wall. External coil currents keep the CT off the outer wall (levitation) and then rapidly compress it inwards. The optimal external coil configuration greatly improved both the levitated CT lifetime and the rate of shots with good compressional flux conservation. As confirmed by spectrometer data, the improved levitation field profile reduced plasma impurity levels by suppressing the interaction between plasma and the insulating outer wall during the formation process. We developed an energy and toroidal flux conserving finite element axisymmetric MHD code to study CT formation and compression. The Braginskii MHD equations with anisotropic heat conduction were implemented. To simulate plasma / insulating wall interaction, we couple the vacuum field solution in the insulating region to the full MHD solution in the remainder of the domain. We see good agreement between simulation and experiment results. Partly funded by NSERC and MITACS Accelerate.

  17. DCS - A high flux beamline for time resolved dynamic compression science – Design highlights

    Energy Technology Data Exchange (ETDEWEB)

    Capatina, D., E-mail: capatina@aps.anl.gov; D’Amico, K., E-mail: kdamico@aps.anl.gov; Nudell, J., E-mail: jnudell@aps.anl.gov; Collins, J., E-mail: collins@aps.anl.gov; Schmidt, O., E-mail: oschmidt@aps.anl.gov [Advanced Photon Source, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, IL 60439 (United States)

    2016-07-27

    The Dynamic Compression Sector (DCS) beamline, a national user facility for time resolved dynamic compression science supported by the National Nuclear Security Administration (NNSA) of the Department of Energy (DOE), has recently completed construction and is being commissioned at Sector 35 of the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). The beamline consists of a First Optics Enclosure (FOE) and four experimental enclosures. A Kirkpatrick–Baez focusing mirror system with 2.2 mrad incident angles in the FOE delivers pink beam to the experimental stations. A refocusing Kirkpatrick–Baez mirror system is situated in each of the two most downstream enclosures. Experiments can be conducted in either white, monochromatic, pink or monochromatic-reflected beam mode in any of the experimental stations by changing the position of two interlocked components in the FOE. The beamline Radiation Safety System (RSS) components have been designed to handle the continuous beam provided by two in-line revolver undulators with periods of 27 and 30 mm, at closed gap, 150 mA beam current, and passing through a power limiting aperture of 1.5 x 1.0 mm{sup 2}. A novel pink beam end station stop [1] is used to stop the continuous and focused pink beam which can achieve a peak heat flux of 105 kW/mm{sup 2}. A new millisecond shutter design [2] is used to deliver a quick pulse of beam to the sample, synchronized with the dynamic event, the microsecond shutter, and the storage ring clock.

  18. The effect of breast compression on mass conspicuity in digital mammography

    International Nuclear Information System (INIS)

    Saunders, Robert S. Jr; Samei, Ehsan

    2008-01-01

    This study analyzed how the inherent quality of diagnostic information in digital mammography could be affected by breast compression. A digital mammography system was modeled using a Monte Carlo algorithm based on the Penelope program, which has been successfully used to model several medical imaging systems. First, the Monte Carlo program was validated against previous measurements and simulations. Once validated, the Monte Carlo software modeled a digital mammography system by tracking photons through a voxelized software breast phantom, containing anatomical structures and breast masses, and following photons until they were absorbed by a selenium-based flat-panel detector. Simulations were performed for two compression conditions (standard compression and 12.5% reduced compression) and three photon flux conditions (constant flux, constant detector signal, and constant glandular dose). The results showed that reduced compression led to higher scatter fractions, as expected. For the constant photon flux condition, decreased compression also reduced glandular dose. For constant glandular dose, the SdNR for a 4 cm breast was 0.60±0.11 and 0.62±0.11 under standard and reduced compressions, respectively. For the 6 cm case with constant glandular dose, the SdNR was 0.50±0.11 and 0.49±0.10 under standard and reduced compressions, respectively. The results suggest that if a particular imaging system can handle an approximately 10% increase in total tube output and 10% decrease in detector signal, breast compression can be reduced by about 12% in terms of breast thickness with little impact on image quality or dose.

  19. 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

  20. Hydroelastic behaviour of a structure exposed to an underwater explosion.

    Science.gov (United States)

    Colicchio, G; Greco, M; Brocchini, M; Faltinsen, O M

    2015-01-28

    The hydroelastic interaction between an underwater explosion and an elastic plate is investigated num- erically through a domain-decomposition strategy. The three-dimensional features of the problem require a large computational effort, which is reduced through a weak coupling between a one-dimensional radial blast solver, which resolves the blast evolution far from the boundaries, and a three-dimensional compressible flow solver used where the interactions between the compression wave and the boundaries take place and the flow becomes three-dimensional. The three-dimensional flow solver at the boundaries is directly coupled with a modal structural solver that models the response of the solid boundaries like elastic plates. This enables one to simulate the fluid-structure interaction as a strong coupling, in order to capture hydroelastic effects. The method has been applied to the experimental case of Hung et al. (2005 Int. J. Impact Eng. 31, 151-168 (doi:10.1016/j.ijimpeng.2003.10.039)) with explosion and structure sufficiently far from other boundaries and successfully validated in terms of the evolution of the acceleration induced on the plate. It was also used to investigate the interaction of an underwater explosion with the bottom of a close-by ship modelled as an orthotropic plate. In the application, the acoustic phase of the fluid-structure interaction is examined, highlighting the need of the fluid-structure coupling to capture correctly the possible inception of cavitation. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  1. Digital micromirror devices in Raman trace detection of explosives

    Science.gov (United States)

    Glimtoft, Martin; Svanqvist, Mattias; Ågren, Matilda; Nordberg, Markus; Östmark, Henric

    2016-05-01

    Imaging Raman spectroscopy based on tunable filters is an established technique for detecting single explosives particles at stand-off distances. However, large light losses are inherent in the design due to sequential imaging at different wavelengths, leading to effective transmission often well below 1 %. The use of digital micromirror devices (DMD) and compressive sensing (CS) in imaging Raman explosives trace detection can improve light throughput and add significant flexibility compared to existing systems. DMDs are based on mature microelectronics technology, and are compact, scalable, and can be customized for specific tasks, including new functions not available with current technologies. This paper has been focusing on investigating how a DMD can be used when applying CS-based imaging Raman spectroscopy on stand-off explosives trace detection, and evaluating the performance in terms of light throughput, image reconstruction ability and potential detection limits. This type of setup also gives the possibility to combine imaging Raman with non-spatially resolved fluorescence suppression techniques, such as Kerr gating. The system used consists of a 2nd harmonics Nd:YAG laser for sample excitation, collection optics, DMD, CMOScamera and a spectrometer with ICCD camera for signal gating and detection. Initial results for compressive sensing imaging Raman shows a stable reconstruction procedure even at low signals and in presence of interfering background signal. It is also shown to give increased effective light transmission without sacrificing molecular specificity or area coverage compared to filter based imaging Raman. At the same time it adds flexibility so the setup can be customized for new functionality.

  2. Generation of neutrons in a plane system by explosive implosion of a variable-density liner

    International Nuclear Information System (INIS)

    Kaliski, S.

    1978-01-01

    The neutron yield has been calculated in a plane system at explosive implosion of a variable density liner into the explosive region. Due to high speed of implosion effected with the aid of a cumulative cone the neutron yield has already been obtained for the plane wave incident and reflected in deuterium gas. This has permitted an analytical approximate estimation of the neutron yield. This yield may be enhanced in a further phase of compression. (author)

  3. Compression experiments on the TOSKA tokamak

    International Nuclear Information System (INIS)

    Cima, G.; McGuire, K.M.; Robinson, D.C.; Wootton, A.J.

    1980-10-01

    Results from minor radius compression experiments on a tokamak plasma in TOSCA are reported. The compression is achieved by increasing the toroidal field up to twice its initial value in 200μs. Measurements show that particles and magnetic flux are conserved. When the initial energy confinement time is comparable with the compression time, energy gains are greater than for an adiabatic change of state. The total beta value increases. Central beta values approximately 3% are measured when a small major radius compression is superimposed on a minor radius compression. Magnetic field fluctuations are affected: both the amplitude and period decrease. Starting from low energy confinement times, approximately 200μs, increases in confinement times up to approximately 1 ms are measured. The increase in plasma energy results from a large reduction in the power losses during the compression. When the initial energy confinement time is much longer than the compression time, the parameter changes are those expected for an adiabatic change of state. (author)

  4. Modeling compressible multiphase flows with dispersed particles in both dense and dilute regimes

    Science.gov (United States)

    McGrath, T.; St. Clair, J.; Balachandar, S.

    2018-05-01

    Many important explosives and energetics applications involve multiphase formulations employing dispersed particles. While considerable progress has been made toward developing mathematical models and computational methodologies for these flows, significant challenges remain. In this work, we apply a mathematical model for compressible multiphase flows with dispersed particles to existing shock and explosive dispersal problems from the literature. The model is cast in an Eulerian framework, treats all phases as compressible, is hyperbolic, and satisfies the second law of thermodynamics. It directly applies the continuous-phase pressure gradient as a forcing function for particle acceleration and thereby retains relaxed characteristics for the dispersed particle phase that remove the constituent material sound velocity from the eigenvalues. This is consistent with the expected characteristics of dispersed particle phases and can significantly improve the stable time-step size for explicit methods. The model is applied to test cases involving the shock and explosive dispersal of solid particles and compared to data from the literature. Computed results compare well with experimental measurements, providing confidence in the model and computational methods applied.

  5. The plasma formation stage in magnetic compression/magnetized target fusion (MAGO/MTF)

    International Nuclear Information System (INIS)

    Lindemuth, I.R.; Reinovsky, R.E.; Chrien, R.E.

    1996-01-01

    In early 1992, emerging governmental policy in the US and Russia began to encourage ''lab-to-lab'' interactions between the All- Russian Scientific Research Institute of Experimental Physics (VNIIEF) and the Los Alamos National Laboratory (LANL). As nuclear weapons stockpiles and design activities were being reduced, highly qualified scientists become for fundamental scientific research of interest to both nations. VNIIEF and LANL found a common interest in the technology and applications of magnetic flux compression, the technique for converting the chemical energy released by high-explosives into intense electrical pulses and intensely concentrated magnetic energy. Motivated originally to evaluate any possible defense applications of flux compression technology, the two teams worked independently for many years, essentially unaware of the others' accomplishments. But, an early US publication stimulated Soviet work, and the Soviets followed with a report of the achievement of 25 MG. During the cold war, a series of conferences on Megagauss Magnetic Field Generation and Related Topics became a forum for scientific exchange of ideas and accomplishments. Because of relationships established at the Megagauss conferences, VNIIEF and LANL were able to respond quickly to the initiatives of their respective governments. In late 1992, following the Megagauss VI conference, the two institutions agreed to combine resources to perform a series of experiments that essentially could not be performed by each institution independently. Beginning in September, 1993, the two institutions have performed eleven joint experimental campaigns, either at VNIIEF or at LANL. Megagauss- VII has become the first of the series to include papers with joint US and Russian authorship. In this paper, we review the joint LANL/VNIIEF experimental work that has relevance to a relatively unexplored approach to controlled thermonuclear fusion

  6. 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.

  7. Shock compression of nitrobenzene; Nitoro benzen no shogeki asshoku

    Energy Technology Data Exchange (ETDEWEB)

    Kozu, Naoshi; Arai, Mitsuru; Tamura, Masamitsu [The University of Tokyo, Tokyo (Japan). Department of Chemical System Engineering; Yoshida, Masatake [National Institute of Materials and Chemical Research, Tsukuba (Japan)

    1999-08-31

    The Hugoniot (4 - 30 x 10{sup 9}Pa) of nitrobenzene has been obtained by shock compression experiments. Explosive plane-wae generators were used for plane shock wave generation. The obtained Hugoniot consists of two linear lines (U{sub s} (x 10{sup 3}m/s) = 2.52 + 1.23U{sub p} (x 10{sup 3}m/s)(0.8explosives and V.V.Yakyshev's experiments of shock compression of nitrobenzene. (author)

  8. 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.

  9. Properties and Behavior of Geopolymer Concrete Subjected to Explosive Air Blast Loading: A Review

    Directory of Open Access Journals (Sweden)

    Mohd Mortar Nurul Aida

    2017-01-01

    Full Text Available The severe damage to civilian buildings, public area, jet aircraft impact and defense target under explosive blast loading can cause a huge property loss. Most of researcher discusses the topics on design the concrete material model to sustain againts the explosive detonation. The implementation of modern reinforcement steels and fibres in ordinary Portland cement (OPC concrete matrix can reduce the extreme loading effects. However, most researchers have proved that geopolymer concrete (GPC has better mechanical properties towards high performance concrete, compared to OPC. GPC has the high early compressive strength and high ability to resist the thermal energy from explosive detonation. In addition, OPC production is less environmental friendly than geopolymer cement. Geopolymer used can lead to environmental protection besides being improved in mechanical properties. Thus, this paper highlighted on an experimental, numerical and the analytical studies cause of the explosive detonation impact to concrete structures.

  10. Analytical study on spherules from Toungouska explosion site

    International Nuclear Information System (INIS)

    Jehanno, C.; Robin, E.; Rocchia, R.; Boclet, D.; Danon, J.

    1989-01-01

    Eighty years after the event, the Tunguska explosion of june 1908, has not found a satisfactory explanation. The cosmic bolide, supposed responsible for the event, has not yet been identified but numerous magnetic spherules have been recovered in the vicinity of the explosion site. Eighty spherules have been studied and compared with the Fe-Ni spherules from the steady micrometeoroid flux. Ninety percents of them cannot be identified with any known micrometeoroid families; their low average iridium content rather suggests a terrestrial origin. Five other spherules are obviously Fe-Ni spherules of the steady micrometeoroid rain and, thus, are unrelated the Tunguska event. Only three of the 80 spherules, consisting of a single iron oxide phase, could have been produced by the event. (author)

  11. Potential hazards of compressed air energy storage in depleted natural gas reservoirs.

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Paul W.; Grubelich, Mark Charles; Bauer, Stephen J.

    2011-09-01

    This report is a preliminary assessment of the ignition and explosion potential in a depleted hydrocarbon reservoir from air cycling associated with compressed air energy storage (CAES) in geologic media. The study identifies issues associated with this phenomenon as well as possible mitigating measures that should be considered. Compressed air energy storage (CAES) in geologic media has been proposed to help supplement renewable energy sources (e.g., wind and solar) by providing a means to store energy when excess energy is available, and to provide an energy source during non-productive or low productivity renewable energy time periods. Presently, salt caverns represent the only proven underground storage used for CAES. Depleted natural gas reservoirs represent another potential underground storage vessel for CAES because they have demonstrated their container function and may have the requisite porosity and permeability; however reservoirs have yet to be demonstrated as a functional/operational storage media for compressed air. Specifically, air introduced into a depleted natural gas reservoir presents a situation where an ignition and explosion potential may exist. This report presents the results of an initial study identifying issues associated with this phenomena as well as possible mitigating measures that should be considered.

  12. Magnetogasdynamic spherical shock wave in a non-ideal gas under gravitational field with conductive and radiative heat fluxes

    Science.gov (United States)

    Nath, G.; Vishwakarma, J. P.

    2016-11-01

    Similarity solutions are obtained for the flow behind a spherical shock wave in a non-ideal gas under gravitational field with conductive and radiative heat fluxes, in the presence of a spatially decreasing azimuthal magnetic field. The shock wave is driven by a piston moving with time according to power law. The radiation is considered to be of the diffusion type for an optically thick grey gas model and the heat conduction is expressed in terms of Fourier's law for heat conduction. Similarity solutions exist only when the surrounding medium is of constant density. The gas is assumed to have infinite electrical conductivity and to obey a simplified van der Waals equation of state. It is shown that an increase of the gravitational parameter or the Alfven-Mach number or the parameter of the non-idealness of the gas decreases the compressibility of the gas in the flow-field behind the shock, and hence there is a decrease in the shock strength. The pressure and density vanish at the inner surface (piston) and hence a vacuum is formed at the center of symmetry. The shock waves in conducting non-ideal gas under gravitational field with conductive and radiative heat fluxes can be important for description of shocks in supernova explosions, in the study of a flare produced shock in the solar wind, central part of star burst galaxies, nuclear explosion etc. The solutions obtained can be used to interpret measurements carried out by space craft in the solar wind and in neighborhood of the Earth's magnetosphere.

  13. Design of foil implosion system for Pioneer I experiments

    International Nuclear Information System (INIS)

    Erickson, D.J.; Caird, R.S.; Fowler, C.M.

    1985-01-01

    A foil implosion system is described that integrates an explosive flux-compression generator, a flat plate feed section with power conditioning switches, and a vacuum electrode region containing a cylindrical foil/plasma load. Power conditioning, obtained with an explosive-driven plasma compression opening switch and explosive-actuated closing switches, provides a submicrosecond multimegampere pulse for the implosion of an aluminum plasma. The flat plate section is configured for bidirectional feed to the coaxial vacuum electrodes. Important considerations in the design of the vacuum power flow region include gap failure, feed symmetry, and radial diagnostic access. The system presently accommodates a foil radius of 3 cm. Innovative foil insertion and clamping techniques are also described

  14. Explosive dome eruptions modulated by periodic gas-driven inflation

    Science.gov (United States)

    Johnson, Jeffrey B.; Lyons, John; Andrews, B. J.; Lees, J.M.

    2014-01-01

    Volcan Santiaguito (Guatemala) “breathes” with extraordinary regularity as the edifice's conduit system accumulates free gas, which periodically vents to the atmosphere. Periodic pressurization controls explosion timing, which nearly always occurs at peak inflation, as detected with tiltmeters. Tilt cycles in January 2012 reveal regular 26 ± 6 min inflation/deflation cycles corresponding to at least ~101 kg/s of gas fluxing the system. Very long period (VLP) earthquakes presage explosions and occur during cycles when inflation rates are most rapid. VLPs locate ~300 m below the vent and indicate mobilization of volatiles, which ascend at ~50 m/s. Rapid gas ascent feeds pyroclast-laden eruptions lasting several minutes and rising to ~1 km. VLPs are not observed during less rapid inflation episodes; instead, gas vents passively through the conduit producing no infrasound and no explosion. These observations intimate that steady gas exsolution and accumulation in shallow reservoirs may drive inflation cycles at open-vent silicic volcanoes.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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-...

  20. Liner velocity, current, and symmetry measurements on the 32 MA flux compression generator experiment ALT-1

    CERN Document Server

    Clark, D A; Rodríguez, G; Tabaka, L J

    2001-01-01

    Summary form only given, as follows. A flux compression generator based pulse power system, designed, built, and fielded by a Russian team at the All Russian Scientific Research Institute of Experimental Physics (VNIIEF), was used to successfully drive an aluminum liner to velocities greater than 10 km/sec. The experiment objective was to demonstrate performance of a precision liner implosion at Atlas current of 30 MA or greater. Diagnostics to measure liner performance were an essential part of the experiment. An experimental team from Los Alamos National Laboratory (LANL) provided a suite of diagnostics to measure liner performance. Three diagnostics were fielded. 1. a velocity interferometer (VISAR) to continuously measure the liner inner surface velocity from throughout the entire range of travel. 2. Two Faraday rotation devices to measure liner current during the implosion. 3. Sixteen fiber optic impact pins to record liner impact time and provide axial and azimuthal symmetry information. All diagnostics...

  1. CHROMOSPHERIC AND CORONAL WAVE GENERATION IN A MAGNETIC FLUX SHEATH

    International Nuclear Information System (INIS)

    Kato, Yoshiaki; Hansteen, Viggo; Gudiksen, Boris; Wedemeyer, Sven; Carlsson, Mats; Steiner, Oskar

    2016-01-01

    Using radiation magnetohydrodynamic simulations of the solar atmospheric layers from the upper convection zone to the lower corona, we investigate the self-consistent excitation of slow magneto-acoustic body waves (slow modes) in a magnetic flux concentration. We find that the convective downdrafts in the close surroundings of a two-dimensional flux slab “pump” the plasma inside it in the downward direction. This action produces a downflow inside the flux slab, which encompasses ever higher layers, causing an upwardly propagating rarefaction wave. The slow mode, excited by the adiabatic compression of the downflow near the optical surface, travels along the magnetic field in the upward direction at the tube speed. It develops into a shock wave at chromospheric heights, where it dissipates, lifts the transition region, and produces an offspring in the form of a compressive wave that propagates further into the corona. In the wake of downflows and propagating shock waves, the atmosphere inside the flux slab in the chromosphere and higher tends to oscillate with a period of ν ≈ 4 mHz. We conclude that this process of “magnetic pumping” is a most plausible mechanism for the direct generation of longitudinal chromospheric and coronal compressive waves within magnetic flux concentrations, and it may provide an important heat source in the chromosphere. It may also be responsible for certain types of dynamic fibrils.

  2. CHROMOSPHERIC AND CORONAL WAVE GENERATION IN A MAGNETIC FLUX SHEATH

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Yoshiaki; Hansteen, Viggo; Gudiksen, Boris; Wedemeyer, Sven; Carlsson, Mats [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo (Norway); Steiner, Oskar, E-mail: yoshiaki.kato@astro.uio.no [Kiepenheuer-Institut für Sonnenphysik, Schöneckstrasse 6, D-79104 Freiburg (Germany)

    2016-08-10

    Using radiation magnetohydrodynamic simulations of the solar atmospheric layers from the upper convection zone to the lower corona, we investigate the self-consistent excitation of slow magneto-acoustic body waves (slow modes) in a magnetic flux concentration. We find that the convective downdrafts in the close surroundings of a two-dimensional flux slab “pump” the plasma inside it in the downward direction. This action produces a downflow inside the flux slab, which encompasses ever higher layers, causing an upwardly propagating rarefaction wave. The slow mode, excited by the adiabatic compression of the downflow near the optical surface, travels along the magnetic field in the upward direction at the tube speed. It develops into a shock wave at chromospheric heights, where it dissipates, lifts the transition region, and produces an offspring in the form of a compressive wave that propagates further into the corona. In the wake of downflows and propagating shock waves, the atmosphere inside the flux slab in the chromosphere and higher tends to oscillate with a period of ν ≈ 4 mHz. We conclude that this process of “magnetic pumping” is a most plausible mechanism for the direct generation of longitudinal chromospheric and coronal compressive waves within magnetic flux concentrations, and it may provide an important heat source in the chromosphere. It may also be responsible for certain types of dynamic fibrils.

  3. Explosion Amplitude Reduction due to Fractures in Water-Saturated and Dry Granite

    Science.gov (United States)

    Stroujkova, A. F.; Leidig, M.; Bonner, J. L.

    2013-12-01

    Empirical observations made at the Semipalatinsk Test Site suggest that nuclear tests in the fracture zones left by previous explosions ('repeat shots') show reduced seismic amplitudes compared to the nuclear tests in virgin rocks. Likely mechanisms for the amplitude reduction in the repeat shots include increased porosity and reduced strength and elastic moduli, leading to pore closing and frictional sliding. Presence of pore water significantly decreases rock compressibility and strength, thus affecting seismic amplitudes. A series of explosion experiments were conducted in order to define the physical mechanism responsible for the amplitude reduction and to quantify the degree of the amplitude reduction in fracture zones of previously detonated explosions. Explosions in water-saturated granite were conducted in central New Hampshire in 2011 and 2012. Additional explosions in dry granite were detonated in Barre, VT in 2013. The amplitude reduction is different between dry and water-saturated crystalline rocks. Significant reduction in seismic amplitudes (by a factor of 2-3) in water-saturated rocks was achieved only when the repeat shot was detonated in the extensive damage zone created by a significantly larger (by a factor of 5) explosion. In case where the first and the second explosions were similar in yield, the amplitude reduction was relatively modest (5-20%). In dry rocks the amplitude reduction reached a factor of 2 even in less extensive damage zones. In addition there are differences in frequency dependence of the spectral amplitude ratios between explosions in dry and water-saturated rocks. Thus the amplitude reduction is sensitive to the extent of the damage zone as well as the pore water content.

  4. Energy transfer in compressible magnetohydrodynamic turbulence for isothermal self-gravitating fluids

    Science.gov (United States)

    Banerjee, Supratik; Kritsuk, Alexei G.

    2018-02-01

    Three-dimensional, compressible, magnetohydrodynamic turbulence of an isothermal, self-gravitating fluid is analyzed using two-point statistics in the asymptotic limit of large Reynolds numbers (both kinetic and magnetic). Following an alternative formulation proposed by Banerjee and Galtier [Phys. Rev. E 93, 033120 (2016), 10.1103/PhysRevE.93.033120; J. Phys. A: Math. Theor. 50, 015501 (2017), 10.1088/1751-8113/50/1/015501], an exact relation has been derived for the total energy transfer. This approach results in a simpler relation expressed entirely in terms of mixed second-order structure functions. The kinetic, thermodynamic, magnetic, and gravitational contributions to the energy transfer rate can be easily separated in the present form. By construction, the new formalism includes such additional effects as global rotation, the Hall term in the induction equation, etc. The analysis shows that solid-body rotation cannot alter the energy flux rate of compressible turbulence. However, the contribution of a uniform background magnetic field to the flux is shown to be nontrivial unlike in the incompressible case. Finally, the compressible, turbulent energy flux rate does not vanish completely due to simple alignments, which leads to a zero turbulent energy flux rate in the incompressible case.

  5. Effect of CH4–Air Ratios on Gas Explosion Flame Microstructure and Propagation Behaviors

    Directory of Open Access Journals (Sweden)

    Ying Zhang

    2012-10-01

    Full Text Available To reveal the inner mechanism of gas explosion dynamic behavior affected by gas equivalent concentration, a high speed Schlieren image system and flow field measurement technology was applied to record the gas explosion flame propagation and flame structure transition. The results show that a flame front structure transition occurs, followed by a flame accelerating propagation process. The laminar to turbulence transition was the essential cause of the flame structure changes. The laminar flame propagation behavior was influenced mainly by gas expansion and fore-compressive wave effect, while the turbulent flame speed mostly depended on turbulence intensity, which also played an important role in peak value of the explosive pressure and flame speed. On the condition that the laminar-turbulent transition was easier to form, the conclusion was drawn that, the lowest CH4 concentration for maximum overpressure can be obtained, which was the essential reason why the ideal explosive concentration differs under different test conditions.

  6. CoGI: Towards Compressing Genomes as an Image.

    Science.gov (United States)

    Xie, Xiaojing; Zhou, Shuigeng; Guan, Jihong

    2015-01-01

    Genomic science is now facing an explosive increase of data thanks to the fast development of sequencing technology. This situation poses serious challenges to genomic data storage and transferring. It is desirable to compress data to reduce storage and transferring cost, and thus to boost data distribution and utilization efficiency. Up to now, a number of algorithms / tools have been developed for compressing genomic sequences. Unlike the existing algorithms, most of which treat genomes as one-dimensional text strings and compress them based on dictionaries or probability models, this paper proposes a novel approach called CoGI (the abbreviation of Compressing Genomes as an Image) for genome compression, which transforms the genomic sequences to a two-dimensional binary image (or bitmap), then applies a rectangular partition coding algorithm to compress the binary image. CoGI can be used as either a reference-based compressor or a reference-free compressor. For the former, we develop two entropy-based algorithms to select a proper reference genome. Performance evaluation is conducted on various genomes. Experimental results show that the reference-based CoGI significantly outperforms two state-of-the-art reference-based genome compressors GReEn and RLZ-opt in both compression ratio and compression efficiency. It also achieves comparable compression ratio but two orders of magnitude higher compression efficiency in comparison with XM--one state-of-the-art reference-free genome compressor. Furthermore, our approach performs much better than Gzip--a general-purpose and widely-used compressor, in both compression speed and compression ratio. So, CoGI can serve as an effective and practical genome compressor. The source code and other related documents of CoGI are available at: http://admis.fudan.edu.cn/projects/cogi.htm.

  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. Compression of toroidal plasma by imploding plasma-liner

    International Nuclear Information System (INIS)

    Ikuta, Kazunari.

    1979-07-01

    A new concept of compressing a plasma in a closed magnetic configuration by a version of liner implosion flux compression technique is considered. The liner consists of a dense plasma cylinder, i.e. the plasma-liner. Maximum compression ratio of toroidal plasma is determined just by the initial density ratio of the toroidal plasma to the liner plasma because of the Rayleigh-Taylor instability. A start-up senario of plasma-liner is also proposed with a possible application of this concept to the creation of a burning plasma in reversed field configurations, i.e. burning plasma vortex. (author)

  9. NRGC: a novel referential genome compression algorithm.

    Science.gov (United States)

    Saha, Subrata; Rajasekaran, Sanguthevar

    2016-11-15

    Next-generation sequencing techniques produce millions to billions of short reads. The procedure is not only very cost effective but also can be done in laboratory environment. The state-of-the-art sequence assemblers then construct the whole genomic sequence from these reads. Current cutting edge computing technology makes it possible to build genomic sequences from the billions of reads within a minimal cost and time. As a consequence, we see an explosion of biological sequences in recent times. In turn, the cost of storing the sequences in physical memory or transmitting them over the internet is becoming a major bottleneck for research and future medical applications. Data compression techniques are one of the most important remedies in this context. We are in need of suitable data compression algorithms that can exploit the inherent structure of biological sequences. Although standard data compression algorithms are prevalent, they are not suitable to compress biological sequencing data effectively. In this article, we propose a novel referential genome compression algorithm (NRGC) to effectively and efficiently compress the genomic sequences. We have done rigorous experiments to evaluate NRGC by taking a set of real human genomes. The simulation results show that our algorithm is indeed an effective genome compression algorithm that performs better than the best-known algorithms in most of the cases. Compression and decompression times are also very impressive. The implementations are freely available for non-commercial purposes. They can be downloaded from: http://www.engr.uconn.edu/~rajasek/NRGC.zip CONTACT: rajasek@engr.uconn.edu. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  10. The reactants equation of state for the tri-amino-tri-nitro-benzene (TATB) based explosive PBX 9502

    Science.gov (United States)

    Aslam, Tariq D.

    2017-07-01

    The response of high explosives (HEs), due to mechanical and/or thermal insults, is of great importance for both safety and performance. A major component of how an HE responds to these stimuli stems from its reactant equation of state (EOS). Here, the tri-amino-tri-nitro-benzene based explosive PBX 9502 is investigated by examining recent experiments. Furthermore, a complete thermal EOS is calibrated based on the functional form devised by Wescott, Stewart, and Davis [J. Appl. Phys. 98, 053514 (2005)]. It is found, by comparing to earlier calibrations, that a variety of thermodynamic data are needed to sufficiently constrain the EOS response over a wide range of thermodynamic state space. Included in the calibration presented here is the specific heat as a function of temperature, isobaric thermal expansion, and shock Hugoniot response. As validation of the resulting model, isothermal compression and isentropic compression are compared with recent experiments.

  11. Terminal velocity of liquids and granular materials dispersed by a high explosive

    Science.gov (United States)

    Loiseau, J.; Pontalier, Q.; Milne, A. M.; Goroshin, S.; Frost, D. L.

    2018-04-01

    The explosive dispersal of a layer of solid particles or a layer of liquid surrounding a spherical high-explosive charge generates a turbulent, multiphase flow. Shock compression of the material layer during the initial acceleration may partially consolidate the material, leading to the formation of jet-like structures when the layer fragments and sheds particles upon release. Similarly, release of a shock-compressed liquid shell causes the nucleation of cavitation sites, leading to the radial breakup of the shell and the formation of jets upon expansion. In the current study, a wide variety of granular materials and liquids were explosively dispersed. The maximum terminal jet tip or shell velocity was measured using high-speed videography. Charges were constructed using thin-walled glass bulbs of various diameters and contained a central C-4 charge surrounded by the material to be dispersed. This permitted variation of the ratio of material mass to charge mass (M/C) from 4 to 300. Results indicated that material velocity broadly correlates with predictions of the Gurney model. For liquids, the terminal velocity was accurately predicted by the Gurney model. For granular materials, Gurney over-predicted the terminal velocity by 25-60%, depending on the M/C ratio, with larger M/C values exhibiting larger deficits. These deficits are explained by energy dissipation during the collapse of voids in the granular material bed. Velocity deficits were insensitive to the degree of jetting and granular material properties. Empirical corrections to the Gurney model are presented with improved agreement with the dry powder experimental velocities.

  12. Terminal velocity of liquids and granular materials dispersed by a high explosive

    Science.gov (United States)

    Loiseau, J.; Pontalier, Q.; Milne, A. M.; Goroshin, S.; Frost, D. L.

    2018-05-01

    The explosive dispersal of a layer of solid particles or a layer of liquid surrounding a spherical high-explosive charge generates a turbulent, multiphase flow. Shock compression of the material layer during the initial acceleration may partially consolidate the material, leading to the formation of jet-like structures when the layer fragments and sheds particles upon release. Similarly, release of a shock-compressed liquid shell causes the nucleation of cavitation sites, leading to the radial breakup of the shell and the formation of jets upon expansion. In the current study, a wide variety of granular materials and liquids were explosively dispersed. The maximum terminal jet tip or shell velocity was measured using high-speed videography. Charges were constructed using thin-walled glass bulbs of various diameters and contained a central C-4 charge surrounded by the material to be dispersed. This permitted variation of the ratio of material mass to charge mass ( M/ C) from 4 to 300. Results indicated that material velocity broadly correlates with predictions of the Gurney model. For liquids, the terminal velocity was accurately predicted by the Gurney model. For granular materials, Gurney over-predicted the terminal velocity by 25-60%, depending on the M/ C ratio, with larger M/ C values exhibiting larger deficits. These deficits are explained by energy dissipation during the collapse of voids in the granular material bed. Velocity deficits were insensitive to the degree of jetting and granular material properties. Empirical corrections to the Gurney model are presented with improved agreement with the dry powder experimental velocities.

  13. Shock Initiation of Damaged Explosives

    Energy Technology Data Exchange (ETDEWEB)

    Chidester, S K; Vandersall, K S; Tarver, C M

    2009-10-22

    Explosive and propellant charges are subjected to various mechanical and thermal insults that can increase their sensitivity over the course of their lifetimes. To quantify this effect, shock initiation experiments were performed on mechanically and thermally damaged LX-04 (85% HMX, 15% Viton by weight) and PBX 9502 (95% TATB, 5% Kel-F by weight) to obtain in-situ manganin pressure gauge data and run distances to detonation at various shock pressures. We report the behavior of the HMX-based explosive LX-04 that was damaged mechanically by applying a compressive load of 600 psi for 20,000 cycles, thus creating many small narrow cracks, or by cutting wedge shaped parts that were then loosely reassembled, thus creating a few large cracks. The thermally damaged LX-04 charges were heated to 190 C for long enough for the beta to delta solid - solid phase transition to occur, and then cooled to ambient temperature. Mechanically damaged LX-04 exhibited only slightly increased shock sensitivity, while thermally damaged LX-04 was much more shock sensitive. Similarly, the insensitive explosive PBX 9502 was mechanically damaged using the same two techniques. Since PBX 9502 does not undergo a solid - solid phase transition but does undergo irreversible or 'rachet' growth when thermally cycled, thermal damage to PBX 9502 was induced by this procedure. As for LX-04, the thermally damaged PBX 9502 demonstrated a greater shock sensitivity than mechanically damaged PBX 9502. The Ignition and Growth reactive flow model calculated the increased sensitivities by igniting more damaged LX-04 and PBX 9502 near the shock front based on the measured densities (porosities) of the damaged charges.

  14. 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.

  15. Flux Limiter Lattice Boltzmann Scheme Approach to Compressible Flows with Flexible Specific-Heat Ratio and Prandtl Number

    International Nuclear Information System (INIS)

    Gan Yanbiao; Li Yingjun; Xu Aiguo; Zhang Guangcai

    2011-01-01

    We further develop the lattice Boltzmann (LB) model [Physica A 382 (2007) 502] for compressible flows from two aspects. Firstly, we modify the Bhatnagar-Gross-Krook (BGK) collision term in the LB equation, which makes the model suitable for simulating flows with different Prandtl numbers. Secondly, the flux limiter finite difference (FLFD) scheme is employed to calculate the convection term of the LB equation, which makes the unphysical oscillations at discontinuities be effectively suppressed and the numerical dissipations be significantly diminished. The proposed model is validated by recovering results of some well-known benchmarks, including (i) The thermal Couette flow; (ii) One- and two-dimensional Riemann problems. Good agreements are obtained between LB results and the exact ones or previously reported solutions. The flexibility, together with the high accuracy of the new model, endows the proposed model considerable potential for tracking some long-standing problems and for investigating nonlinear nonequilibrium complex systems. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  16. Acoustic and tephra records of explosive eruptions at West Mata submarine volcano, NE Lau Basin

    Science.gov (United States)

    Dziak, R. P.; Bohnenstiehl, D. R.; Baker, E. T.; Matsumoto, H.; Caplan-Auerbach, J.; Mack, C. J.; Embley, R. W.; Merle, S. G.; Walker, S. L.; Lau, T. A.

    2013-12-01

    West Mata is a 1200 m deep submarine volcano where explosive boninite eruptions were directly observed in May 2009. Here we present long-term acoustic and tephra records of West Mata explosion activity from three deployments of hydrophone and particle sensor moorings beginning on 8 January 2009. These records provide insights into the character of explosive magma degassing occurring at the volcano's summit vent until the decline and eventual cessation of the eruption during late 2010 and early 2011. The detailed acoustic records show three types of volcanic signals, 1) discrete explosions, 2) diffuse explosions, and 3) volcanic tremor. Discrete explosions are short duration, high amplitude broad-band signals caused by rapid gas bubble release. Diffuse signals are likely a result of 'trap-door' explosions where a quench cap of cooled lava forms over the magmatic vent but gas pressure builds underneath the cap. This pressure eventually causes the cap to breach and gas is explosively released until pressure reduces and the cap once again forms. Volcanic tremor is typified by narrow-band, long-duration signals with overtones, as well as narrow-band tones that vary frequency over time between 60-100 Hz. The harmonic tremor is thought to be caused by modulation of rapid, short duration gas explosion pulses and not a magma resonance phenomenon. The variable frequency tones may be caused by focused degassing or hydrothermal fluid flow from a narrow volcanic vent or conduit. High frequency (>30 Hz) tremor-like bands of energy are a result of interference caused by multipath wide-band signals, including sea-surface reflected acoustic phases, that arrive at the hydrophone with small time delays. Acoustic data suggest that eruption velocities for a single explosion range from 4-50 m s-1, although synchronous arrival of explosion signals has complicated our efforts to estimate long-term gas flux. Single explosions exhibit ~4-40 m3 s-1 of total volume flux (gas and rock) but

  17. Spall strength and ejecta production of gold under explosively driven shock wave compression

    International Nuclear Information System (INIS)

    La Lone, B. M.; Stevens, G. D.; Turley, W. D.; Veeser, L. R.; Holtkamp, D. B.

    2013-01-01

    Explosively driven shock wave experiments were conducted to characterize the spall strength and ejecta production of high-purity cast gold samples. The samples were from 0.75 to 1.84 mm thick and 30 mm in diameter. Peak stresses up to 44 GPa in gold were generated using PBX-9501 high explosive. Sample free surface and ejecta velocities were recorded using photonic Doppler velocimetry techniques. Lithium niobate pins were used to quantify the time dependence of the ejecta density and the total ejected mass. An optical framing camera for time-resolved imaging and a single-image x-ray radiograph were used for additional characterization. Free surface velocities exhibited a range of spall strengths from 1.7 to 2.4 GPa (mean: 2.0 ±0.3 GPa). The pullback signals were faint, minimal ringing was observed in the velocity records, and the spall layer continued to decelerate after first pull back. These results suggest finite tensile strength was present for some time after the initial void formation. Ejecta were observed for every sample with a roughened free surface, and the ejecta density increased with increased surface roughness, which was different in every experiment. The total ejected mass is consistent with the missing mass model.

  18. 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.

  19. 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

  20. Polarisation Spectral Synthesis For Type Ia Supernova Explosion Models

    Science.gov (United States)

    Bulla, Mattia

    2017-02-01

    Despite their relevance across a broad range of astrophysical research topics, Type Ia supernova explosions are still poorly understood and answers to the questions of when, why and how these events are triggered remain unclear. In this respect, polarisation offers a unique opportunity to discriminate between the variety of possible scenarios. The observational evidence that Type Ia supernovae are associated with rather low polarisation signals (smaller than a few per cent) places strong constraints for models and calls for modest asphericities in the progenitor system and/or explosion mechanism.The goal of this thesis is to assess the validity of contemporary Type Ia supernova explosion models by testing whether their predicted polarisation signatures can account for the small signals usually observed. To this end, we have implemented and tested an innovative Monte Carlo scheme in the radiative transfer code artis. Compared to previous Monte Carlo approaches, this technique produces synthetic observables (light curves, flux and polarisation spectra) with a substantial reduction in the Monte Carlo noise and therefore in the required computing time. This improvement is particularly crucial for our study as we aim to extract very weak polarisation signals, comparable to those detected in Type Ia supernovae. We have also demonstrated the applicability of this method to other classes of supernovae via a preliminary study of the first spectropolarimetry observations of superluminous supernovae.Using this scheme, we have calculated synthetic spectropolarimetry for three multi-dimensional explosion models recently proposed as promising candidates to explain Type Ia supernovae. Our findings highlight the power of spectropolarimetry in testing and discriminating between different scenarios. While all the three models predict light curves and flux spectra that are similar to each others and reproduce those observed in Type Ia supernovae comparably well, polarisation does

  1. Particle acceleration in relativistic magnetic flux-merging events

    Science.gov (United States)

    Lyutikov, Maxim; Sironi, Lorenzo; Komissarov, Serguei S.; Porth, Oliver

    2017-12-01

    Using analytical and numerical methods (fluid and particle-in-cell simulations) we study a number of model problems involving merger of magnetic flux tubes in relativistic magnetically dominated plasma. Mergers of current-carrying flux tubes (exemplified by the two-dimensional `ABC' structures) and zero-total-current magnetic flux tubes are considered. In all cases regimes of spontaneous and driven evolution are investigated. We identify two stages of particle acceleration during flux mergers: (i) fast explosive prompt X-point collapse and (ii) ensuing island merger. The fastest acceleration occurs during the initial catastrophic X-point collapse, with the reconnection electric field of the order of the magnetic field. During the X-point collapse, particles are accelerated by charge-starved electric fields, which can reach (and even exceed) values of the local magnetic field. The explosive stage of reconnection produces non-thermal power-law tails with slopes that depend on the average magnetization . For plasma magnetization 2$ the spectrum power-law index is 2$ ; in this case the maximal energy depends linearly on the size of the reconnecting islands. For higher magnetization, 2$ , the spectra are hard, , yet the maximal energy \\text{max}$ can still exceed the average magnetic energy per particle, , by orders of magnitude (if is not too close to unity). The X-point collapse stage is followed by magnetic island merger that dissipates a large fraction of the initial magnetic energy in a regime of forced magnetic reconnection, further accelerating the particles, but proceeds at a slower reconnection rate.

  2. Modeling rainfall infiltration on hillslopes using Flux-concentration relation and time compression approximation

    Science.gov (United States)

    Wang, Jie; Chen, Li; Yu, Zhongbo

    2018-02-01

    Rainfall infiltration on hillslopes is an important issue in hydrology, which is related to many environmental problems, such as flood, soil erosion, and nutrient and contaminant transport. This study aimed to improve the quantification of infiltration on hillslopes under both steady and unsteady rainfalls. Starting from Darcy's law, an analytical integral infiltrability equation was derived for hillslope infiltration by use of the flux-concentration relation. Based on this equation, a simple scaling relation linking the infiltration times on hillslopes and horizontal planes was obtained which is applicable for both small and large times and can be used to simplify the solution procedure of hillslope infiltration. The infiltrability equation also improved the estimation of ponding time for infiltration under rainfall conditions. For infiltration after ponding, the time compression approximation (TCA) was applied together with the infiltrability equation. To improve the computational efficiency, the analytical integral infiltrability equation was approximated with a two-term power-like function by nonlinear regression. Procedures of applying this approach to both steady and unsteady rainfall conditions were proposed. To evaluate the performance of the new approach, it was compared with the Green-Ampt model for sloping surfaces by Chen and Young (2006) and Richards' equation. The proposed model outperformed the sloping Green-Ampt, and both ponding time and infiltration predictions agreed well with the solutions of Richards' equation for various soil textures, slope angles, initial water contents, and rainfall intensities for both steady and unsteady rainfalls.

  3. Dwell-time effect on the synthesis of a nano-structured material in water by using Ni wire explosion

    International Nuclear Information System (INIS)

    Eom, Gyu Sub; Kwon, Hyeok Jung; Cho, Yong Sub; Paek, Kwang Hyun; Joo, Won Tae

    2014-01-01

    Nickel nano-structured materials are synthesized by using a wire explosion in water. Based on an analysis of each step of the wire explosion, we propose insufficient energy deposition before a plasma restrike as the cause for the inclusion of coarse particles in the wire-explosion product. We confirmed that more energy, in excess of 30%, could be deposited by increasing the dwell time, which resulted from a compression of vapor by the surrounding water and from suppression of plasma restrikes. Because of an increased energy loss into the surrounding water, the specific energy increased by two-fold compared to a gas atmosphere. The synthesized nano-structured nickel showed a uniform particle size of 20 nm with a few coarse particles that were mainly metallic nickel with a little oxide and hydroxide phases. The possibility for large-volume production through a continuous explosion of 300 shots was confirmed.

  4. Pigeonholing pyroclasts: Insights from the 19 March 2008 explosive eruption of Kīlauea volcano

    Science.gov (United States)

    Houghton, Bruce F.; Swanson, D.A.; Carey, R.J.; Rausch, J.; Sutton, A.J.

    2011-01-01

    We think, conventionally, of volcanic explosive eruptions as being triggered in one of two ways: by release and expansion of volatiles dissolved in the ejected magma (magmatic explosions) or by transfer of heat from magma into an external source of water (phreatic or phreatomagmatic explosions). We document here an event where neither magma nor an external water source was involved in explosive activity at K??lauea. Instead, the eruption was powered by the expansion of decoupled magmatic volatiles released from deeper magma, which was not ejected by the eruption, and the trigger was a collapse of near-surface wall rocks that then momentarily blocked that volatile flux. Mapping of the advected fall deposit a day after this eruption has highlighted the difficulty of constraining deposit edges from unobserved or prehistoric eruptions of all magnitudes. Our results suggest that the dispersal area of advected fall deposits could be miscalculated by up to 30% of the total, raising issues for accurate hazard zoning and assessment. Eruptions of this type challenge existing classification schemes for pyroclastic deposits and explosive eruptions and, in the past, have probably been interpreted as phreatic explosions, where the eruptive mechanism has been assumed to involve flashing of groundwater to steam. ?? 2011 Geological Society of America.

  5. Experimental investigation of dynamic compression and spallation of Cerium at pressures up to 6 GPa

    Science.gov (United States)

    Zubareva, A. N.; Kolesnikov, S. A.; Utkin, A. V.

    2014-05-01

    In this study the experiments on one-dimensional dynamic compression of Cerium (Ce) samples to pressures of 0.5 to 6 GPa using various types of explosively driven generators were conducted. VISAR laser velocimeter was used to obtain Ce free surface velocity profiles. The isentropic compression wave was registered for γ-phase of Ce at pressures lower than 0.76 GPa that corresponds to γ-α phase transition pressure in Ce. Shock rarefaction waves were also registered in several experiments. Both observations were the result of the anomalous compressibility of γ-phase of Ce. On the basis of our experimental results the compression isentrope of Ce γ-phase was constructed. Its comparison with volumetric compression curves allowed to estimate the magnitude of shear stress at dynamic compression conditions for Ce. Spall strength measurements were also conducted for several samples. They showed a strong dependence of the spall strength of Ce on the strain rate.

  6. Experimental investigation of dynamic compression and spallation of cerium at pressures up to 6 GPa

    International Nuclear Information System (INIS)

    Zubareva, A N; Kolesnikov, S A; Utkin, A V

    2014-01-01

    In this study the experiments on one-dimensional dynamic compression of Cerium (Ce) samples to pressures of 0.5 to 6 GPa using various types of explosively driven generators were conducted. VISAR laser velocimeter was used to obtain Ce free surface velocity profiles. The isentropic compression wave was registered for γ-phase of Ce at pressures lower than 0.76 GPa that corresponds to γ-α phase transition pressure in Ce. Shock rarefaction waves were also registered in several experiments. Both observations were the result of the anomalous compressibility of γ-phase of Ce. On the basis of our experimental results the compression isentrope of Ce γ-phase was constructed. Its comparison with volumetric compression curves allowed to estimate the magnitude of shear stress at dynamic compression conditions for Ce. Spall strength measurements were also conducted for several samples. They showed a strong dependence of the spall strength of Ce on the strain rate.

  7. Splitting of inviscid fluxes for real gases

    Science.gov (United States)

    Liou, Meng-Sing; Van Leer, Bram; Shuen, Jian-Shun

    1990-01-01

    Flux-vector and flux-difference splittings for the inviscid terms of the compressible flow equations are derived under the assumption of a general equation of state for a real gas in equilibrium. No necessary assumptions, approximations for auxiliary quantities are introduced. The formulas derived include several particular cases known for ideal gases and readily apply to curvilinear coordinates. Applications of the formulas in a TVD algorithm to one-dimensional shock-tube and nozzle problems show their quality and robustness.

  8. Shock compression and flash-heating of molecular adsorbates on the picosecond time scale

    Science.gov (United States)

    Berg, Christopher Michael

    An ultrafast nonlinear coherent laser spectroscopy termed broadband multiplex vibrational sum-frequency generation (SFG) with nonresonant suppression was employed to monitor vibrational transitions of molecular adsorbates on metallic substrates during laser-driven shock compression and flash-heating. Adsorbates were in the form of well-ordered self-assembled monolayers (SAMs) and included molecular explosive simulants, such as nitroaromatics, and long chain-length alkanethiols. Based on reflectance measurements of the metallic substrates, femtosecond flash-heating pulses were capable of producing large-amplitude temperature jumps with DeltaT = 500 K. Laser-driven shock compression of SAMs produced pressures up to 2 GPa, where 1 GPa ≈ 1 x 104 atm. Shock pressures were estimated via comparison with frequency shifts observed in the monolayer vibrational transitions during hydrostatic pressure measurements in a SiC anvil cell. Molecular dynamics during flash-heating and shock loading were probed with vibrational SFG spectroscopy with picosecond temporal resolution and sub-nanometer spatial resolution. Flash-heating studies of 4-nitrobenzenethiolate (NBT) on Au provided insight into effects from hot-electron excitation of the molecular adsorbates at early pump-probe delay times. At longer delay times, effects from the excitation of SAM lattice modes and lower-energy NBT vibrations were shown. In addition, flash-heating studies of alkanethiolates demonstrated chain disordering behaviors as well as interface thermal conductances across the Au-SAM junction, which was of specific interest within the context of molecular electronics. Shock compression studies of molecular explosive simulants, such as 4-nitrobenzoate (NBA), demonstrated the proficiency of this technique to observe shock-induced molecular dynamics, in this case orientational dynamics, on the picosecond time scale. Results validated the utilization of these refined shock loading techniques to probe the shock

  9. 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)

  10. Collapsing criteria for vapor film around solid spheres as a fundamental stage leading to vapor explosion

    Energy Technology Data Exchange (ETDEWEB)

    Freud, Roy [Nuclear Research Center - Negev, Beer-Sheva (Israel)], E-mail: freud@bgu.ac.il; Harari, Ronen [Nuclear Research Center - Negev, Beer-Sheva (Israel); Sher, Eran [Pearlstone Center for Aeronautical Studies, Department of Mechanical Engineering, Ben-Gurion University, Beer-Sheva (Israel)

    2009-04-15

    Following a partial fuel-melting accident, a Fuel-Coolant Interaction (FCI) can result with the fragmentation of the melt into tiny droplets. A vapor film is then formed between the melt fragments and the coolant, while preventing a contact between them. Triggering, propagation and expansion typically follow the premixing stage. In the triggering stage, vapor film collapse around one or several of the fragments occurs. This collapse can be the result of fragments cooling, a sort of mechanical force, or by any other means. When the vapor film collapses and the coolant re-establishes contact with the dry surface of the hot melt, it may lead to a very rapid and rather violent boiling. In the propagation stage the shock wave front leads to stripping of the films surrounding adjacent droplets which enhance the fragmentation and the process escalates. During this process a large quantity of liquid vaporizes and its expansion can result in destructive mechanical damage to the surrounding structures. This multiphase thermal detonation in which high pressure shock wave is formed is regarded as 'vapor explosion'. The film boiling and its possible collapse is a fundamental stage leading to vapor explosion. If the interaction of the melt and the coolant does not result in a film boiling, no explosion occurs. Many studies have been devoted to determine the minimum temperature and heat flux that is required to maintain a film boiling. The present experimental study examines the minimum temperature that is required to maintain a film boiling around metal spheres immersed into a liquid (subcooled distilled water) reservoir. In order to simulate fuel fragments that are small in dimension and has mirror-like surface, small spheres coated with anti-oxidation layer were used. The heat flux from the spheres was calculated from the sphere's temperature profiles and the sphere's properties. The vapor film collapse was associated with a sharp rise of the heat flux

  11. Collapsing criteria for vapor film around solid spheres as a fundamental stage leading to vapor explosion

    International Nuclear Information System (INIS)

    Freud, Roy; Harari, Ronen; Sher, Eran

    2009-01-01

    Following a partial fuel-melting accident, a Fuel-Coolant Interaction (FCI) can result with the fragmentation of the melt into tiny droplets. A vapor film is then formed between the melt fragments and the coolant, while preventing a contact between them. Triggering, propagation and expansion typically follow the premixing stage. In the triggering stage, vapor film collapse around one or several of the fragments occurs. This collapse can be the result of fragments cooling, a sort of mechanical force, or by any other means. When the vapor film collapses and the coolant re-establishes contact with the dry surface of the hot melt, it may lead to a very rapid and rather violent boiling. In the propagation stage the shock wave front leads to stripping of the films surrounding adjacent droplets which enhance the fragmentation and the process escalates. During this process a large quantity of liquid vaporizes and its expansion can result in destructive mechanical damage to the surrounding structures. This multiphase thermal detonation in which high pressure shock wave is formed is regarded as 'vapor explosion'. The film boiling and its possible collapse is a fundamental stage leading to vapor explosion. If the interaction of the melt and the coolant does not result in a film boiling, no explosion occurs. Many studies have been devoted to determine the minimum temperature and heat flux that is required to maintain a film boiling. The present experimental study examines the minimum temperature that is required to maintain a film boiling around metal spheres immersed into a liquid (subcooled distilled water) reservoir. In order to simulate fuel fragments that are small in dimension and has mirror-like surface, small spheres coated with anti-oxidation layer were used. The heat flux from the spheres was calculated from the sphere's temperature profiles and the sphere's properties. The vapor film collapse was associated with a sharp rise of the heat flux during the cooling

  12. 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

  13. 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

  14. A study on stress corrosion cracking of explosive plugged part

    International Nuclear Information System (INIS)

    Kaga, Seiichi; Fujii, Katsuhiro; Yamamoto, Yoshiaki; Sakuma, Koosuke; Hibi, Seiji; Morimoto, Hiroyoshi.

    1986-01-01

    Studies on the stress corrosion cracking of explosive plugged part are conducted. SUS 304 stainless steel is used as testing material. The distribution of residual stress in plug and tube plate after plugging is obtained. The effect of residual stress on the stress corrosion cracking is studied. Residual stress in tube plate near the plug is compressive and stress corrosion cracking dose not occur in the tube plate there, and it occurs on the inner surface of plug because of residual tensile stress in axial direction of the plug. Stress corrosion test in MgCl 2 solution under constant load is conducted. The susceptibility to stress corrosion cracking of the explosive bonded boundary is lower than that of base metal because of greater resistance to plastic deformation. Stress corrosion test in high temperature and high pressure pure water is also conducted by means of static type of autoclave but stress corrosion cracking does not occur under the testing condition used. (author)

  15. Numerical computation of underwater explosions due to fuel-coolant interactions

    International Nuclear Information System (INIS)

    Lee, J.H.S.; Frost, D.L.; Knystautas, R.; Teodorczyk, A.; Ciccarelli, G.; Thibault, P.; Penrose, J.

    1989-03-01

    If coarse molten material is released into a coolant the possibility exists for a violent steam explosion. A detailed quantitative description of the processes involved in steam explosions is currently beyond the capabilities of the scientific community. However, a conservative estimate of the pressure transients resulting from a steam explosion can be obtained by studying the dynamics of the shock associated with the expansion of a high-pressure vapour bubble. In this study, the hydrodynamic equations governing the shock propagation of an expanding bubble were integrated numerically using the Flux Corrected Transport code. Simpler acoustic models based on experience with underwater explosions were also developed and used to estimate pressure transients and to calculate the peak pressures for benchmark cases. The results were found to be an order of magnitude higher than the corresponding pressures obtained using a complex model developed by Henry. A simplified version of the Henry model was developed by neglecting the complex description of the two-phase flow inside the ruptured tube and the arbitrarily assumed heat transfer and condensation rates. Results from the simplified model were found to be generally similar to, but had higher peak pressures than those obtained using the Henry model. It is concluded that the results produced by simple acoustic models, or by a simplified Henry model, are more conservative than the corresponding results obtained with the original Henry model

  16. Investigation of shock compressed plasma parameters by interaction with magnetic field

    International Nuclear Information System (INIS)

    Dudin, S. V.; Fortov, V. E.; Gryaznov, V. K.; Mintsev, V. B.; Shilkin, N. S.; Ushnurtsev, A. E.

    1998-01-01

    The Hall effect parameters in shock compressed air, helium and xenon have been estimated and results of experiments with air and helium plasma are presented. Explosively driven shock tubes were used for the generation of strong shock waves. To obtain magnetic field a solenoid was winded over the shock tube. Calculations of dense shock compressed plasma parameters were carried out to plan the experiments. In the experiments with the magnetic field of ∼5 T it was found, that air plasma slug was significantly heated by the whirlwind electrical field. The reflected shock waves technique was used in the experiments with helium. Results on measurements of electrical conductivity and electron concentration of helium are presented

  17. Air Compressibility Effect on Bouwer and Rice Seepage Meter.

    Science.gov (United States)

    Peng, Xin; Zhan, Hongbin

    2017-11-01

    Measuring a disconnected streambed seepage flux using a seepage meter can give important streambed information and help understanding groundwater-surface water interaction. In this study, we provide a correction for calculating the seepage flux rate with the consideration of air compressibility inside the manometer of the Bouwer and Rice seepage meter. We notice that the effect of air compressibility in the manometer is considerably larger when more air is included in the manometer. We find that the relative error from neglecting air compressibility can be constrained within 5% if the manometer of the Bouwer and Rice seepage meter is shorter than 0.8 m and the experiment is done in a suction mode in which air is pumped out from the manometer before the start of measurement. For manometers longer than 0.8 m, the relative error will be larger than 5%. It may be over 10% if the manometer height is longer than 1.5 m and the experiment is done in a no-suction mode, in which air is not pumped out from the manometer before the start of measurement. © 2017, National Ground Water Association.

  18. 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.

  19. 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.

  20. A nonlinear relaxation/quasi-Newton algorithm for the compressible Navier-Stokes equations

    Science.gov (United States)

    Edwards, Jack R.; Mcrae, D. S.

    1992-01-01

    A highly efficient implicit method for the computation of steady, two-dimensional compressible Navier-Stokes flowfields is presented. The discretization of the governing equations is hybrid in nature, with flux-vector splitting utilized in the streamwise direction and central differences with flux-limited artificial dissipation used for the transverse fluxes. Line Jacobi relaxation is used to provide a suitable initial guess for a new nonlinear iteration strategy based on line Gauss-Seidel sweeps. The applicability of quasi-Newton methods as convergence accelerators for this and other line relaxation algorithms is discussed, and efficient implementations of such techniques are presented. Convergence histories and comparisons with experimental data are presented for supersonic flow over a flat plate and for several high-speed compression corner interactions. Results indicate a marked improvement in computational efficiency over more conventional upwind relaxation strategies, particularly for flowfields containing large pockets of streamwise subsonic flow.

  1. Multidimensional flux-limited advection schemes

    International Nuclear Information System (INIS)

    Thuburn, J.

    1996-01-01

    A general method for building multidimensional shape preserving advection schemes using flux limiters is presented. The method works for advected passive scalars in either compressible or incompressible flow and on arbitrary grids. With a minor modification it can be applied to the equation for fluid density. Schemes using the simplest form of the flux limiter can cause distortion of the advected profile, particularly sideways spreading, depending on the orientation of the flow relative to the grid. This is partly because the simple limiter is too restrictive. However, some straightforward refinements lead to a shape-preserving scheme that gives satisfactory results, with negligible grid-flow angle-dependent distortion

  2. 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

  3. Design and construction of an explosive detection system by Tna methods, using 252Cf radioisotope source

    International Nuclear Information System (INIS)

    Tavakkoli Farsouli, A.

    1999-01-01

    Bombs concealed in luggage have threatened human life and property throughout the world's traffic. The plastic explosives could not checked by the X-ray detecting device. Thermal Neutron Activation method has been tested in the present work for non-destructive detection of explosives. A radioisotope neutron source 252 Cf and two gamma spectroscopy systems have been used as a tool to find explosives, regardless of the bomb's shape and the packing materials. The MCNP code has been used to design the neutronic section of the system. The measured thermal neutron fluxes by the gold foils in some location of the system were in good agreement with those data obtained by the MCNP code. Also, detection limits for nitrogen in various counting times were measured. The measurements show that the system is capable to detect 417 gr of HMX explosive material (158 gr nitrogen) by 10 minutes of counting time. To modify the system and to decrease the detection limits some opinions are given

  4. Near-Source Mechanism for Creating Shear Content from Buried Explosions

    Science.gov (United States)

    Steedman, D. W.; Bradley, C. R.

    2017-12-01

    The Source Physics Experiment (SPE) has the goal of developing a greater understanding of explosion phenomenology at various spatial scales, from near-source to the far-field. SPE Phase I accomplished a series of six chemical explosive tests of varying scaled depth of burial within a borehole in granite. The testbed included an extensive array of triaxial accelerometers. Velocity traces derived from these accelerometers allow for detailed study of the shock environment close in to the explosion. A specific goal of SPE is to identify various mechanisms for generating shear within the propagation environment and how this might be informative on the identification of explosive events that otherwise fail historic compression wave energy/shear wave energy (P/S) event discrimination. One of these sources was hypothesized to derive from slippage along joint sets near to the source. Velocity traces from SPE Phase I events indicate that motion tangential to a theoretically spherical shock wave are initially quiescent after shock arrival. But this period of quiescence is followed by a sudden increase in amplitude that consistently occurs just after the peak of the radial velocity (i.e., onset of shock unloading). The likelihood of occurrence of this response is related to yield-scaled depth-of-burial (SDOB). We describe a mechanism where unloading facilitates dilation of closed joints accompanied by a release of shear energy stored during compression. However, occurrence of this mechanism relies on relative amplitudes between the shock loading caused at a point and the in situ stress: at too large a SDOB the stored energy is insufficient to overcome the combination of the overburden stress and traction on the joint. On the other hand, too small of a SDOB provides that the in situ stress is insufficient to keep joints from storing stress, thus overriding the release mechanism and mitigating rupture-like slippage. We develop a notional relationship between SPE Phase I SDOB and

  5. Numerical investigation of particle-blast interaction during explosive dispersal of liquids and granular materials

    Science.gov (United States)

    Pontalier, Q.; Lhoumeau, M.; Milne, A. M.; Longbottom, A. W.; Frost, D. L.

    2018-04-01

    Experiments show that when a high-explosive charge with embedded particles or a charge surrounded by a layer of liquid or granular material is detonated, the flow generated is perturbed by the motion of the particles and the blast wave profile differs from that of an ideal Friedlander form. Initially, the blast wave overpressure is reduced due to the energy dissipation resulting from compaction, fragmentation, and heating of the particle bed, and acceleration of the material. However, as the blast wave propagates, particle-flow interactions collectively serve to reduce the rate of decay of the peak blast wave overpressure. Computations carried out with a multiphase hydrocode reproduce the general trends observed experimentally and highlight the transition between the particle acceleration/deceleration phases, which is not accessible experimentally, since the particles are obscured by the detonation products. The dependence of the particle-blast interaction and the blast mitigation effectiveness on the mitigant to explosive mass ratio, the particle size, and the initial solid volume fraction is investigated systematically. The reduction in peak blast overpressure is, as in experiments, primarily dependent on the mass ratio of material to explosive, with the particle size, density, and initial porosity of the particle bed playing secondary roles. In the near field, the blast overpressure decreases sharply with distance as the particles are accelerated by the flow. When the particles decelerate due to drag, energy is returned to the flow and the peak blast overpressure recovers and reaches values similar to that of a bare explosive charge for low mass ratios. Time-distance trajectory plots of the particle and blast wave motion with the pressure field superimposed, illustrate the weak pressure waves generated by the motion of the particle layer which travel upstream and perturb the blast wave motion. Computation of the particle and gas momentum flux in the multiphase

  6. Numerical investigation of particle-blast interaction during explosive dispersal of liquids and granular materials

    Science.gov (United States)

    Pontalier, Q.; Lhoumeau, M.; Milne, A. M.; Longbottom, A. W.; Frost, D. L.

    2018-05-01

    Experiments show that when a high-explosive charge with embedded particles or a charge surrounded by a layer of liquid or granular material is detonated, the flow generated is perturbed by the motion of the particles and the blast wave profile differs from that of an ideal Friedlander form. Initially, the blast wave overpressure is reduced due to the energy dissipation resulting from compaction, fragmentation, and heating of the particle bed, and acceleration of the material. However, as the blast wave propagates, particle-flow interactions collectively serve to reduce the rate of decay of the peak blast wave overpressure. Computations carried out with a multiphase hydrocode reproduce the general trends observed experimentally and highlight the transition between the particle acceleration/deceleration phases, which is not accessible experimentally, since the particles are obscured by the detonation products. The dependence of the particle-blast interaction and the blast mitigation effectiveness on the mitigant to explosive mass ratio, the particle size, and the initial solid volume fraction is investigated systematically. The reduction in peak blast overpressure is, as in experiments, primarily dependent on the mass ratio of material to explosive, with the particle size, density, and initial porosity of the particle bed playing secondary roles. In the near field, the blast overpressure decreases sharply with distance as the particles are accelerated by the flow. When the particles decelerate due to drag, energy is returned to the flow and the peak blast overpressure recovers and reaches values similar to that of a bare explosive charge for low mass ratios. Time-distance trajectory plots of the particle and blast wave motion with the pressure field superimposed, illustrate the weak pressure waves generated by the motion of the particle layer which travel upstream and perturb the blast wave motion. Computation of the particle and gas momentum flux in the multiphase

  7. Rotating flux compressor for energy conversion

    International Nuclear Information System (INIS)

    Chowdhuri, P.; Linton, T.W.; Phillips, J.A.

    1983-01-01

    The rotating flux compressor (RFC) converts rotational kinetic energy into an electrical output pulse which would have higher energy than the electrical energy initially stored in the compressor. An RFC has been designed in which wedge-shaped rotor blades pass through the air gaps between successive turns of a solenoid, the stator. Magnetic flux is generated by pulsing the stator solenoids when the inductance is a maximum, i.e., when the flux fills the stator-solenoid volume. Connecting the solenoid across a load conserves the flux which is compressed within the small volume surrounding the stator periphery when the rotor blades cut into the free space between the stator plates, creating a minimum-inductance condition. The unique features of this design are: (1) no electrical connections (brushes) to the rotor; (2) no conventional windings; and (3) no maintenance. The device has been tested up to 5000 rpm of rotor speed

  8. Isentropic compression studies using the NHMFL single turn

    Energy Technology Data Exchange (ETDEWEB)

    Tasker, Douglas G [Los Alamos National Laboratory; Mielke, Charles [Los Alamos National Laboratory; Rodriguez, George [Los Alamos National Laboratory; Rickel, Dwight [Los Alamos National Laboratory

    2010-10-19

    Magnetic isentropic compression experiments (ICE) provide the most accurate shock free compression data for materials at megabar stresses. Recent ICE experiments performed on the Sandia Z-machine (Asay, 1999) and at the Los Alamos High Explosive Pulsed Power facility (Tasker, 2006) are providing our nation with data on material properties in extreme dynamic high stress environments. The LANL National High Magnetic Field Laboratory (NHMFL) can offer a less complex ICE experiment at high stresses (up to {approx}1Mbar) with a high sample throughput and relatively low cost. This is not to say that the NHMFL technique will replace the other methods but rather complement them. For example, NHMFL-ICE is ideal for the development of advanced diagnostics, e.g., to detect phase changes. We will discuss the physics of the NHMFL-ICE experiments and present data from the first proof-of-principle experiments that were performed in September 2010.

  9. The recovery and study of heavy nuclides produced in a nuclear explosion - the Hutch event

    International Nuclear Information System (INIS)

    Hoff, R.W.; Hulet, E.K.

    1970-01-01

    During the explosion of the Hutch device, the target ( 238 U and 232 Th) was subjected to a very high neutron exposure, 2.4 x 10 25 neutrons /cm 2 . Multiple neutron capture reactions resulted in the production of heavy nuclides, up to and including 257Fm. Results of the search for species with A > 257 were negative. The recovery and chemical processing of kilograms of Hutch debris has resulted in the isolation of 10 10 atoms of 257Fm, which is 10 2 times more material than has been available for experimentation in the past. Experimentally significant amounts of other rare nuclides, e.g., : 254 Cf, 251 Cf, 255 -Es, and 250 Cm, have also been separated from the Hutch debris. The production of these nuclides in thermonuclear explosions is shown to be a valuable supplement to the AEC program for reactor production of transplutonium elements. The neutron flux achieved in Hutch was insufficient to even approach production of nuclides in the region of 298 114. A much more intense neutron flux is required. In future experiments, considerable attention must be given to the problem of adequate sample recovery, in order to properly use the ability to subject targets to an exceedingly intense time-integrated neutron flux. (author)

  10. On the Representation of Aquifer Compressibility in General Subsurface Flow Codes: How an Alternate Definition of Aquifer Compressibility Matches Results from the Groundwater Flow Equation

    Science.gov (United States)

    Birdsell, D.; Karra, S.; Rajaram, H.

    2017-12-01

    The governing equations for subsurface flow codes in deformable porous media are derived from the fluid mass balance equation. One class of these codes, which we call general subsurface flow (GSF) codes, does not explicitly track the motion of the solid porous media but does accept general constitutive relations for porosity, density, and fluid flux. Examples of GSF codes include PFLOTRAN, FEHM, STOMP, and TOUGH2. Meanwhile, analytical and numerical solutions based on the groundwater flow equation have assumed forms for porosity, density, and fluid flux. We review the derivation of the groundwater flow equation, which uses the form of Darcy's equation that accounts for the velocity of fluids with respect to solids and defines the soil matrix compressibility accordingly. We then show how GSF codes have a different governing equation if they use the form of Darcy's equation that is written only in terms of fluid velocity. The difference is seen in the porosity change, which is part of the specific storage term in the groundwater flow equation. We propose an alternative definition of soil matrix compressibility to correct for the untracked solid velocity. Simulation results show significantly less error for our new compressibility definition than the traditional compressibility when compared to analytical solutions from the groundwater literature. For example, the error in one calculation for a pumped sandstone aquifer goes from 940 to <70 Pa when the new compressibility is used. Code users and developers need to be aware of assumptions in the governing equations and constitutive relations in subsurface flow codes, and our newly-proposed compressibility function should be incorporated into GSF codes.

  11. 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

  12. Study on the combustion behavior of radiolytically generated hydrogen explosion in small scale annular vessels at the reprocessing plant

    International Nuclear Information System (INIS)

    Kudo, Tatsuya; Tamauchi, Yoshikazu; Arai, Nobuyuki; Dai, Wenbin; Sakaihara, Motohiro; Kanehira, Osamu

    2017-01-01

    Hydrogen is generated by radiolysis of water, etc. in process vessels in reprocessing plant. Usually, the hydrogen is scavenged by compressed air into vessels to prevent hydrogen explosion. When an earthquake beyond design based occurs, for example, the compressed air may stop and the hydrogen starts accumulating in the vessels, and under this condition, an ignition source might set off hydrogen explosion. Therefore, the explosion derived by the radiolytically generated hydrogen is designated as one of severe accidents on Rokkasho Reprocessing Plant in new regulatory requirements. It is important to understand the combustion behavior of hydrogen explosion inside a vessel for consideration of safety measures against the severe accident, because the influences of detonation are not considered in the design basis of vessels. Especially, the investigations about the combustion behavior which considered influence of interior obstacles inside the vessel are not performed yet. In order to investigate the combustion behavior comprehensively, explosion experiment, combustion analysis and structural analysis are carried out using the representative vessels (small scale annular vessel, small scale plate vessel, large scale annular vessel and large scale cylindrical vessel) selected from Rokkasho Reprocessing Plant. In this paper, the results of experiments and analysis of small scale annular vessel (as one of representative vessel, imitated a pulsed column in the reprocessing plant) are reported. As imitated vessels, three vessels are manufactured with different interior obstacle arrangements as follows, A) cylindrical obstacles are faithfully reproduced and are arranged based on the actual vessel, B) cylindrical obstacles are arranged more densely than the actual vessel, and C) there are no obstacles inside the vessel. Experiments of hydrogen explosion are performed under condition of stoichiometric hydrogen-air ratio (premixed hydrogen-air is used). As a result of

  13. 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

  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. A THEMIS Survey of Flux Ropes and Traveling Compression Regions: Location of the Near-Earth Reconnection Site During Solar Minimum

    Science.gov (United States)

    Imber, S. M.; Slavin, J. A.; Auster, H. U.; Angelopoulos, V.

    2011-01-01

    A statistical study of flux ropes and traveling compression regions (TCRs) during the Time History of Events and Macroscale Interactions during Substorms (THEMIS) second tail season has been performed. A combined total of 135 flux ropes and TCRs in the range GSM X approx -14 to -31 R(sub E) were identified, many of these occurring in series of two or more events separated by a few tens of seconds. Those occurring within 10 min of each other were combined into aggregated reconnection events. For the purposes of this survey, these are most likely the products of reconnect ion occurring simultaneously at multiple, closely spaced x-lines as opposed to statistically independent episodes of reconnection. The 135 flux ropes and TCRs were grouped into 87 reconnection events; of these, 28 were moving tailward and 59 were moving Earthward. The average location of the near-Earth x-line determined from statistical analysis of these reconnection events is (X(sub GSM), Y*(sub GSM)) = (-30R(sub E), 5R(sub E)), where Y* includes a correction for the solar aberration angle. A strong east-west asymmetry is present in the tailward events, with >80% being observed at GSM Y* > O. Our results indicate that the Earthward flows are similarly asymmetric in the midtail region, becoming more symmetric inside - 18 R(sub E). Superposed epoch analyses indicate that the occurrence of reconnection closer to the Earth, i.e., X > -20 R(sub E), is associated with elevated solar wind velocity and enhanced negative interplanetary magnetic field B(sub z). Reconnection events taking place closer to the Earth are also far more effective in producing geomagnetic activity, judged by the AL index, than reconnection initiated beyond X approx -25 R(sub E).

  17. Surface energy of explosive nanoparticles

    Science.gov (United States)

    Pineau, Nicolas; Bidault, Xavier; Soulard, Laurent

    2017-06-01

    Recent experimental studies show that nanostructuration has a substantial impact on the detonation of high explosives: a nanostructured one leads to smaller nanodiamonds than a microstructured one. Whether it comes from a higher surface energy or from porosity, the origin of these different behaviors must be investigated. The surface energy of TATB nanoparticles with a radius from 2 nm upto 60 nm has been determined by means of ReaxFF-based simulations. Then, using the Rankine-Hugoniot relations and the equation of states of the bulk material, the contribution of this excess energy to the heating of a shock-compressed nanostructured (and porous) material is evaluated and compared to the thermal effect due to its porosity collapse. A maximum temperature increase of 50 K is found for 4-nm nanoparticles, which remains negligible when compared to the few hundred degrees induced by the compaction work.

  18. Computer model of copper resistivity will improve the efficiency of field-compression devices

    International Nuclear Information System (INIS)

    Burgess, T.J.

    1977-01-01

    By detonating a ring of high explosive around an existing magnetic field, we can, under certain conditions, compress the field and multiply its strength tremendously. In this way, we can duplicate for a fraction of a second the extreme pressures that normally exist only in the interior of stars and planets. Under such pressures, materials may exhibit behavior that will confirm or alter current notions about the fundamental structure of matter and the ongoing processes in planetary interiors. However, we cannot design an efficient field-compression device unless we can calculate the electrical resistivity of certain basic metal components, which interact with the field. To aid in the design effort, we have developed a computer code that calculates the resistivity of copper and other metals over the wide range of temperatures and pressures found in a field-compression device

  19. Metallic hydrogen research

    International Nuclear Information System (INIS)

    Burgess, T.J.; Hawke, R.S.

    1978-01-01

    Theoretical studies predict that molecular hydrogen can be converted to the metallic phase at very high density and pressure. These conditions were achieved by subjecting liquid hydrogen to isentropic compression in a magnetic-flux compression device. Hydrogen became electrically conducting at a density of about 1.06 g/cm 3 and a calculated pressure of about 2 Mbar. In the experimental device, a cylindrical liner, on implosion by high explosive, compresses a magnetic flux which in turn isentropically compresses a hydrogen sample; coaxial conical anvils prevent escape of the sample during compression. One anvil contains a coaxial cable that uses alumina ceramic as an insulator; this probe allows continuous measurement of the electrical conductivity of the hydrogen. A flash x-ray radiograph exposed during the experiment records the location of the sample-tube boundaries and permits calculation of the sample density. The theoretical underpinnings of the metallic transition of hydrogen are briefly summarized, and the experimental apparatus and technique, analytical methods, and results are described. 9 figures

  20. Models of Flux Tubes from Constrained Relaxation

    Indian Academy of Sciences (India)

    tribpo

    J. Astrophys. Astr. (2000) 21, 299 302. Models of Flux Tubes from Constrained Relaxation. Α. Mangalam* & V. Krishan†, Indian Institute of Astrophysics, Koramangala,. Bangalore 560 034, India. *e mail: mangalam @ iiap. ernet. in. † e mail: vinod@iiap.ernet.in. Abstract. We study the relaxation of a compressible plasma to ...

  1. 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.

  2. The Young Massive Stellar Cluster Sandage-96 after the Explosion of SN 2004DJ in NGC 2403

    Science.gov (United States)

    Vinko, J.; Sarneczky, K.; Balog, Z.; Immler, S.; Sugerman, B.; Brown, P. J.; Misselt, K.; Szabo, Gy. M.; Klagyivik, P.; Kun, M.; hide

    2008-01-01

    The bright supernova 2004dj occurred within the young massive stellar cluster Sandage-96 in a spiral arm of NGC 2403, close to other star-forming complexes. New multi-wavelength observations obtained with several ground-based- and space telescopes are combined to study the radiation from Sandage-96 after SN 2004dj faded away. The late-time light curves show that Sandage-96 started to dominate the flux in the optical bands after September, 2006 (+800 days after explosion). The optical fluxes are equal to the pre-explosion ones, suggesting that Sandage-96 has survived the explosion without significant changes in its stellar population. An optical Keck-spectrum obtained at +900 days after explosion shows the dominant blue continuum from the cluster stars shortward of 6000 A as well as strong SN nebular emission lines redward. The integrated SED of the cluster has been extended into the UV-region by archival XMM-Newton and new Swift observations, and compared with theoretical models. The outer parts of the cluster have been resolved by HST allowing the construction of a color-magnitude diagram. The fitting of the cluster SED with theoretical isochrones results in two possible solutions with ages being 9+/-1 Myr and 30+/-10 Myr, depending on the assumed metallicity and the theoretical model family. The isochrone fitting of the color-magnitude diagram indicates that the outer part of the cluster consists of stars having an age dispersion of 16 hypothesis that the outskirt of Sandage-96 is contaminated by stars captured from the field during cluster formation. The young age of Sandage-96 and the comparison of its pre- and post-explosion SEDs suggest a progenitor mass of 15 < or equal to M(sub prog) < 25 Stellar Mass.

  3. 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

  4. The Taylor-Proudman column in a rapidly-rotating compressible fluid I. energy transports

    International Nuclear Information System (INIS)

    Park, Jun Sang

    2014-01-01

    A theoretical study is made of the steady flow of a compressible fluid in a rapidly rotating finite cylinder. Flow is generated by imposing mechanical and/or thermal disturbances at the rotating endwall disks. Both the Ekman and Rossby numbers are small. An examination is made of the energy budget for a control volume in the Ekman boundary layer. A combination of physical variables, which is termed the energy flux content, consisting of temperature and modified angular momentum, emerges to be relevant. The distinguishing features of a compressible fluid, in contrast to those of an incompressible fluid, are noted. A plausible argument is given to explain the difficulty in achieving the Taylor-Proudman column in a compressible rotating fluid. For the Taylor-Proudman column to be sustained, in the interior, it is shown that the net energy transport between the solid disk wall and the interior fluid should vanish. Physical rationalizations are facilitated by resorting to the concept of the afore-stated energy flux content.

  5. 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.

  6. 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.

  7. 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...

  8. DNABIT Compress - Genome compression algorithm.

    Science.gov (United States)

    Rajarajeswari, Pothuraju; Apparao, Allam

    2011-01-22

    Data compression is concerned with how information is organized in data. Efficient storage means removal of redundancy from the data being stored in the DNA molecule. Data compression algorithms remove redundancy and are used to understand biologically important molecules. We present a compression algorithm, "DNABIT Compress" for DNA sequences based on a novel algorithm of assigning binary bits for smaller segments of DNA bases to compress both repetitive and non repetitive DNA sequence. Our proposed algorithm achieves the best compression ratio for DNA sequences for larger genome. Significantly better compression results show that "DNABIT Compress" algorithm is the best among the remaining compression algorithms. While achieving the best compression ratios for DNA sequences (Genomes),our new DNABIT Compress algorithm significantly improves the running time of all previous DNA compression programs. Assigning binary bits (Unique BIT CODE) for (Exact Repeats, Reverse Repeats) fragments of DNA sequence is also a unique concept introduced in this algorithm for the first time in DNA compression. This proposed new algorithm could achieve the best compression ratio as much as 1.58 bits/bases where the existing best methods could not achieve a ratio less than 1.72 bits/bases.

  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. Thermal chemical-mechanical reactive flow model of shock initiation in solid explosives

    International Nuclear Information System (INIS)

    Nicholls, A.L. III; Tarver, C.M.

    1998-01-01

    The three dimensional Arbitrary Lagrange Eulerian hydrodynamic computer code ALE3D with fully coupled thermal-chemical-mechanical material models provides the framework for the development of a physically realistic model of shock initiation and detonation of solid explosives. The processes of hot spot formation during shock compression, subsequent ignition of reaction or failure to react, growth of reaction in individual hot spots, and coalescence of reacting hot spots during the transition to detonation can now be modeled using Arrhenius chemical kinetic rate laws and heat transfer to propagate the reactive flow. This paper discusses the growth rates of reacting hot spots in HMX and TATB and their coalescence during shock to detonation transition. Hot spot deflagration rates are found to be fast enough to consume explosive particles less than 10 mm in diameter during typical shock duration times, but larger particles must fragment and create more reactive surface area in order to be rapidly consumed

  11. The recovery and study of heavy nuclides produced in a nuclear explosion - the Hutch event

    Energy Technology Data Exchange (ETDEWEB)

    Hoff, R W; Hulet, E K [Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)

    1970-05-15

    During the explosion of the Hutch device, the target ({sup 238}U and {sup 232}Th) was subjected to a very high neutron exposure, 2.4 x 10{sup 25} neutrons /cm{sup 2}. Multiple neutron capture reactions resulted in the production of heavy nuclides, up to and including 257Fm. Results of the search for species with A > 257 were negative. The recovery and chemical processing of kilograms of Hutch debris has resulted in the isolation of 10{sup 10} atoms of 257Fm, which is 10{sup 2} times more material than has been available for experimentation in the past. Experimentally significant amounts of other rare nuclides, e.g., :{sup 254}Cf, {sup 251}Cf, {sup 255}-Es, and {sup 250}Cm, have also been separated from the Hutch debris. The production of these nuclides in thermonuclear explosions is shown to be a valuable supplement to the AEC program for reactor production of transplutonium elements. The neutron flux achieved in Hutch was insufficient to even approach production of nuclides in the region of {sup 298}114. A much more intense neutron flux is required. In future experiments, considerable attention must be given to the problem of adequate sample recovery, in order to properly use the ability to subject targets to an exceedingly intense time-integrated neutron flux. (author)

  12. Could a nearby supernova explosion have caused a mass extinction?

    CERN Document Server

    Ellis, Jonathan Richard

    1995-01-01

    We examine the possibility that a nearby supernova explosion could have caused one or more of the mass extinctions identified by palaeontologists. We discuss the likely rate of such events in the light of the recent identification of Geminga as a supernova remnant less than 100 pc away and the discovery of a millisecond pulsar about 150 pc away, and observations of SN 1987A. The fluxes of $\\gamma$ radiation and charged cosmic rays on the Earth are estimated, and their effects on the Earth's ozone layer discussed. A supernova explosion of the order of 10 pc away could be expected every few hundred million years, and could destroy the ozone layer for hundreds of years, letting in potentially lethal solar ultraviolet radiation. In addition to effects on land ecology, this could entail mass destruction of plankton and reef communities, with disastrous consequences for marine life as well. A supernova extinction should be distinguishable from a meteorite impact such as the one that presumably killed the dinosaurs.

  13. 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)

  14. 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)

  15. Detection of explosives and illicit drugs using neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Kiraly, B. E-mail: kiralyb@tigris.klte.hu; Sanami, T.; Doczi, R.; Csikai, J

    2004-01-01

    A procedure developed for the determination of the flux perturbation factor required for the thermal neutron activation analysis of bulky samples of unknown composition has been extended for epithermal neutrons using hydrogenous and graphite moderators. Measurements on the diffusion and backscattering of thermal neutrons in soil components were carried out for the development of novel nuclear methods in order to speed up the humanitarian demining process. Results obtained for the diffusion length were checked by MCNP-4C calculations. In addition, the effect of the weight and density of the explosives on the observation of the anomaly in the reflected thermal neutrons was examined by using different dummy landmines.

  16. 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

  17. 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)

  18. 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.

  19. Compressible Convection Experiment using Xenon Gas in a Centrifuge

    Science.gov (United States)

    Menaut, R.; Alboussiere, T.; Corre, Y.; Huguet, L.; Labrosse, S.; Deguen, R.; Moulin, M.

    2017-12-01

    We present here an experiment especially designed to study compressible convection in the lab. For significant compressible convection effects, the parameters of the experiment have to be optimized: we use xenon gaz in a cubic cell. This cell is placed in a centrifuge to artificially increase the apparent gravity and heated from below. With these choices, we are able to reach a dissipation number close to Earth's outer core value. We will present our results for different heating fluxes and rotation rates. We success to observe an adiabatic gradient of 3K/cm in the cell. Studies of pressure and temperature fluctuations lead us to think that the convection takes place under the form of a single roll in the cell for high heating flux. Moreover, these fluctuations show that the flow is geostrophic due to the high rotation speed. This important role of rotation, via Coriolis force effects, in our experimental setup leads us to develop a 2D quasigeostrophic compressible model in the anelastic liquid approximation. We test numerically this model with the finite element solver FreeFem++ and compare its results with our experimental data. In conclusion, we will present our project for the next experiment in which the cubic cell will be replace by a annulus cell. We will discuss the new expected effects due to this geometry as Rossby waves and zonal flows.

  20. 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.

  1. Dynamic ignition regime of condensed system by radiate heat flux

    International Nuclear Information System (INIS)

    Arkhipov, V A; Zolotorev, N N; Korotkikh, A G; Kuznetsov, V T

    2017-01-01

    The main ignition characteristics of high-energy materials are the ignition time and critical heat flux allowing evaluation of the critical conditions for ignition, fire and explosive safety for the test solid propellants. The ignition process is typically studied in stationary conditions of heat input at constant temperature of the heating surface, environment or the radiate heat flux on the sample surface. In real conditions, ignition is usually effected at variable time-dependent values of the heat flux. In this case, the heated layer is formed on the sample surface in dynamic conditions and significantly depends on the heat flux change, i.e. increasing or decreasing falling heat flux in the reaction period of the propellant sample. This paper presents a method for measuring the ignition characteristics of a high-energy material sample in initiation of the dynamic radiant heat flux, which includes the measurement of the ignition time when exposed to a sample time varying radiant heat flux given intensity. In case of pyroxyline containing 1 wt. % of soot, it is shown that the ignition times are reduced by 20–50 % depending on the initial value of the radiant flux density in initiation by increasing or decreasing radiant heat flux compared with the stationary conditions of heat supply in the same ambient conditions. (paper)

  2. Upgrade of the Detector for Imaging of Explosions

    Science.gov (United States)

    Shekhtman, L. I.; Aulchenko, V. M.; Kudryavtsev, V. N.; Kutovenko, V. D.; Titov, V. M.; Zhulanov, V. V.; Pruuel, E. L.; Ten, K. A.; Tolochko, B. P.

    Methods of dynamic imaging of explosions at a synchrotron radiation (SR) beam and small-angle X-ray scattering experiments with exploding samples are being developed in the Siberian Synchrotron Radiation Center (SSRC) at the Budker Institute of Nuclear Physics for more than fifteen years. The detector for imaging of explosions (DIMEX) was developed for these purposes and successfully operating at the beam line 0 at the VEPP-3 storage ring and at the beam line 8 at the VEPP-4 M storage ring. The DIMEX is based on gas technology and allow to measure SR flux as a function of position and time with spatial resolution of ∼200 μm (FWHM), maximum frame rate of 2 MHz and time resolution of ∼80 ns. Maximum value of the SR flux that can be measured by the present detector corresponds to ∼5000 photons/(channel*bunch) (20 keV average energy, channel area 0.1x0.5 mm2, bunch revolution frequency 4 MHz). Maximum number of frames that can be stored in the present detector is 32 and the number of channels with 0.1 mm width is 512. In order to significantly improve the precision of data obtained by the DIMEX an upgrade of the detector has been started. The electronics of the gaseous version of the detector has been changed such that the new detector is able to operate with frame rate of 8 MHz and store data in up to 100 frames. A new ASIC was developed for this purpose called DMXG64A that includes 64 channels with low noise integrator and 100 analogue memory cells in each channel. Input charge can be stored to and read out from analogue cells with maximum frequency 10 MHz. This new version of the detector is called the DIMEX-G and is planned to be used at the VEPP-3 storage ring and for SAXS studies at the VEPP-4 M storage ring. For imaging of explosions at the beam line 8 at the VEPP-4 M storage ring, where SR flux is expected to be about 10-100 times higher than at the VEPP-3, a new detector based on Si micro-strip technology is being developed. Si micro-strip sensors with

  3. 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.

  4. Energy storage, compression, and switching. Vol. 2

    International Nuclear Information System (INIS)

    Nardi, V.; Bostick, W.H.; Sahlin, H.

    1983-01-01

    This book is a compilation of papers presented at the Second International Conference on Energy Storage, Compression, and Switching, which was held in order to assemble active researchers with a major interest in plasma physics, electron beams, electric and magnetic energy storage systems, high voltage and high current switches, free-electron lasers, and pellet implosion plasma focus. Topics covered include: Slow systems: 50-60 Hz machinery, homopolar generators, slow capacitors, inductors, and solid state switches; Intermediate systems: fast capacitor banks; superconducting storage and switching; gas, vacuum, and dielectric switching; nonlinear (magnetic) switching; imploding liners capacitors; explosive generators; and fuses; and Fast systems: Marx, Blumlein, oil, water, and pressurized water dielectrics; switches; magnetic insulation; electron beams; and plasmas

  5. 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.

  6. 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)

  7. The direct Discontinuous Galerkin method for the compressible Navier-Stokes equations on arbitrary grids

    Science.gov (United States)

    Yang, Xiaoquan; Cheng, Jian; Liu, Tiegang; Luo, Hong

    2015-11-01

    The direct discontinuous Galerkin (DDG) method based on a traditional discontinuous Galerkin (DG) formulation is extended and implemented for solving the compressible Navier-Stokes equations on arbitrary grids. Compared to the widely used second Bassi-Rebay (BR2) scheme for the discretization of diffusive fluxes, the DDG method has two attractive features: first, it is simple to implement as it is directly based on the weak form, and therefore there is no need for any local or global lifting operator; second, it can deliver comparable results, if not better than BR2 scheme, in a more efficient way with much less CPU time. Two approaches to perform the DDG flux for the Navier- Stokes equations are presented in this work, one is based on conservative variables, the other is based on primitive variables. In the implementation of the DDG method for arbitrary grid, the definition of mesh size plays a critical role as the formation of viscous flux explicitly depends on the geometry. A variety of test cases are presented to demonstrate the accuracy and efficiency of the DDG method for discretizing the viscous fluxes in the compressible Navier-Stokes equations on arbitrary grids.

  8. 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)

  9. 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.

  10. 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...

  11. Generation of ultra-fast cumulative water jets by sub-microsecond underwater electrical explosion of conical wire arrays

    Energy Technology Data Exchange (ETDEWEB)

    Shafer, D.; Gurovich, V. Tz.; Gleizer, S.; Gruzinsky, K.; Krasik, Ya. E. [Physics Department, Technion, Haifa 32000 (Israel)

    2015-12-15

    The results of experiments with underwater electrical explosion of modified conical arrays of copper and aluminum wires are presented. A pulsed generator producing a 550 kA-amplitude current with a 400 ns rise time was used in the explosion of the arrays. The array explosion generates water flows converging at the axis of the cone. This flow generates a fast-moving water jet with a velocity exceeding 1.8 × 10{sup 5 }cm/s, which was observed being ejected from the surface of the water covering the array. The positions of the water jet were measured by multiple-exposure fast framing imaging. In experiments, the apex angle of the array, the thickness of the water layer above the arrays, or the material of the wires was altered, which changed the resulting velocities and shapes of the emitted jets. A model that considers the converging stationary flow of a slightly compressible fluid is suggested. The velocities and shapes of the jets obtained by this model agree well with the experimentally measured jet velocities.

  12. DNABIT Compress – Genome compression algorithm

    Science.gov (United States)

    Rajarajeswari, Pothuraju; Apparao, Allam

    2011-01-01

    Data compression is concerned with how information is organized in data. Efficient storage means removal of redundancy from the data being stored in the DNA molecule. Data compression algorithms remove redundancy and are used to understand biologically important molecules. We present a compression algorithm, “DNABIT Compress” for DNA sequences based on a novel algorithm of assigning binary bits for smaller segments of DNA bases to compress both repetitive and non repetitive DNA sequence. Our proposed algorithm achieves the best compression ratio for DNA sequences for larger genome. Significantly better compression results show that “DNABIT Compress” algorithm is the best among the remaining compression algorithms. While achieving the best compression ratios for DNA sequences (Genomes),our new DNABIT Compress algorithm significantly improves the running time of all previous DNA compression programs. Assigning binary bits (Unique BIT CODE) for (Exact Repeats, Reverse Repeats) fragments of DNA sequence is also a unique concept introduced in this algorithm for the first time in DNA compression. This proposed new algorithm could achieve the best compression ratio as much as 1.58 bits/bases where the existing best methods could not achieve a ratio less than 1.72 bits/bases. PMID:21383923

  13. Bubble nucleation in an explosive micro-bubble actuator

    International Nuclear Information System (INIS)

    Van den Broek, D M; Elwenspoek, M

    2008-01-01

    Explosive evaporation occurs when a thin layer of liquid reaches a temperature close to the critical temperature in a very short time. At these temperatures spontaneous nucleation takes place. The nucleated bubbles instantly coalesce forming a vapour film followed by rapid growth due to the pressure impulse. In this paper we take a closer look at the bubble nucleation. The moment of bubble nucleation was determined by both stroboscopic imaging and resistance thermometry. Two nucleation regimes could be distinguished. Several different heater designs were investigated under heat fluxes of hundreds of W mm −2 . A close correspondence between current density in the heater and point of nucleation was found. This results in design rules for effective heaters

  14. Constraints on the progenitor system of the type Ia supernova 2014J from pre-explosion Hubble space telescope imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Patrick L.; Fox, Ori D.; Filippenko, Alexei V.; Shen, Ken J.; Zheng, WeiKang; Graham, Melissa L.; Tucker, Brad E. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Cenko, S. Bradley [NASA/Goddard Space Flight Center, Code 662, Greenbelt, MD 20771 (United States); Prato, Lisa [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Schaefer, Gail, E-mail: pkelly@astro.berkeley.edu [The CHARA Array of Georgia State University, Mount Wilson Observatory, Mount Wilson, CA 91023 (United States)

    2014-07-20

    We constrain the properties of the progenitor system of the highly reddened Type Ia supernova (SN Ia) 2014J in Messier 82 (M82; d ≈ 3.5 Mpc). We determine the supernova (SN) location using Keck-II K-band adaptive optics images, and we find no evidence for flux from a progenitor system in pre-explosion near-ultraviolet through near-infrared Hubble Space Telescope (HST) images. Our upper limits exclude systems having a bright red giant companion, including symbiotic novae with luminosities comparable to that of RS Ophiuchi. While the flux constraints are also inconsistent with predictions for comparatively cool He-donor systems (T ≲ 35,000 K), we cannot preclude a system similar to V445 Puppis. The progenitor constraints are robust across a wide range of R{sub V} and A{sub V} values, but significantly greater values than those inferred from the SN light curve and spectrum would yield proportionally brighter luminosity limits. The comparatively faint flux expected from a binary progenitor system consisting of white dwarf stars would not have been detected in the pre-explosion HST imaging. Infrared HST exposures yield more stringent constraints on the luminosities of very cool (T < 3000 K) companion stars than was possible in the case of SN Ia 2011fe.

  15. Constraints on the progenitor system of the type Ia supernova 2014J from pre-explosion Hubble space telescope imaging

    International Nuclear Information System (INIS)

    Kelly, Patrick L.; Fox, Ori D.; Filippenko, Alexei V.; Shen, Ken J.; Zheng, WeiKang; Graham, Melissa L.; Tucker, Brad E.; Cenko, S. Bradley; Prato, Lisa; Schaefer, Gail

    2014-01-01

    We constrain the properties of the progenitor system of the highly reddened Type Ia supernova (SN Ia) 2014J in Messier 82 (M82; d ≈ 3.5 Mpc). We determine the supernova (SN) location using Keck-II K-band adaptive optics images, and we find no evidence for flux from a progenitor system in pre-explosion near-ultraviolet through near-infrared Hubble Space Telescope (HST) images. Our upper limits exclude systems having a bright red giant companion, including symbiotic novae with luminosities comparable to that of RS Ophiuchi. While the flux constraints are also inconsistent with predictions for comparatively cool He-donor systems (T ≲ 35,000 K), we cannot preclude a system similar to V445 Puppis. The progenitor constraints are robust across a wide range of R V and A V values, but significantly greater values than those inferred from the SN light curve and spectrum would yield proportionally brighter luminosity limits. The comparatively faint flux expected from a binary progenitor system consisting of white dwarf stars would not have been detected in the pre-explosion HST imaging. Infrared HST exposures yield more stringent constraints on the luminosities of very cool (T < 3000 K) companion stars than was possible in the case of SN Ia 2011fe.

  16. Compressibility of the fouling layer formed by membrane bioreactor sludge and supernatant

    DEFF Research Database (Denmark)

    Jørgensen, Mads Koustrup; Poorasgari, Eskandar; Christensen, Morten Lykkegaard

    Membrane bioreactors (MBR) are increasingly used for wastewater treatment as they give high effluent quality, low footprint and efficient sludge degradation. However, the accumulation and deposition of sludge components on and within the membrane (fouling) limits the widespread application of MBR....... Compressibility of the gel layer was studied in a dead-end filtration system, whereas the compressibility of a fouling layer formed by MBR sludge was studied in a submerged system hollow sheet membrane by TMP stepping. It was shown that the fouling layer formed by the MBR sludge was highly compressible within....... Hence, for MBR systems operated at constant flux mode, the applied pressure should be increased over time, to compensate for the lower permeability. Increasing applied pressure causes compression of the fouling layer and results in a more severe permeability decline [1]. In a general view, the fouling...

  17. Role of magnetic flux perturbations in confinement bifurcations in TUMAN-3M

    International Nuclear Information System (INIS)

    Lebedev, S.V.; Andreiko, M.V.; Askinazi, L.G.

    2003-01-01

    Poloidal magnetic flux variations in the small tokamak TUMAN-3M allowed observation of transitions between different confinement modes. The possibility of switching on/off the ohmic H-mode by edge poloidal magnetic flux perturbations has been found. The flux perturbations were created by fast current ramp up/down or by magnetic compression/decompression produced by fast increase/decrease in the toroidal magnetic field. It was found that positive flux perturbations (current ramp-up and magnetic compression scenarios) are useful means of H-mode triggering. If a negative flux perturbation (current ramp-down or magnetic decompression) is applied, the H-mode terminated. Various mechanisms involved in the L-H and H-L transition physics in the flux perturbation experiments were analyzed. The experimental observations of the transitions between confinement modes might be understood in terms of the model of a sheared radial electric field generation, which takes into account the electron Ware drift in a perturbed longitudinal electric field. Another scenario of improved confinement was observed in the initial phase of an ohmic discharge, when change in the poloidal flux is associated with current ramp-up. Variation of the rates of current ramp-up and working gas puffing in the beginning of a discharge resulted in a fast increase in the electron temperature near the axis. The increase correlates with low m/n MHD mode growth. The observed core electron confinement improvement is apparently connected with the rate of current ramp. Deviation from the optimal rate results in disappearance of the improvement. The role of magnetic shear profile and rational magnetic surfaces in the core electron confinement improvement in the initial phase of ohmic discharges is discussed. (author)

  18. Flux and Hall states in ABJM with dynamical flavors

    Energy Technology Data Exchange (ETDEWEB)

    Bea, Yago [Departamento de Física de Partículas and Instituto Galego de Física de Altas Enerxías,Universidade de Santiago de Compostela,E-15782 Santiago de Compostela (Spain); Jokela, Niko [Department of Physics and Helsinki Institute of Physics, University of Helsinki,P.O. Box 64, FIN-00014 (Finland); Lippert, Matthew [Institute for Theoretical Physics, University of Amsterdam,1098XH Amsterdam (Netherlands); Ramallo, Alfonso V. [Departamento de Física de Partículas and Instituto Galego de Física de Altas Enerxías,Universidade de Santiago de Compostela,E-15782 Santiago de Compostela (Spain); Zoakos, Dimitrios [Centro de Física do Porto and Departamento de Física e Astronomia,Faculdade de Ciências da Universidade do Porto,Rua do Campo Alegre 687, 4169-007 Porto (Portugal)

    2015-03-02

    We study the physics of probe D6-branes with quantized internal worldvolume flux in the ABJM background with unquenched massless flavors. This flux breaks parity in the (2+1)-dimensional gauge theory and allows quantum Hall states. Parity breaking is also explicitly demonstrated via the helicity dependence of the meson spectrum. We obtain general expressions for the conductivities, both in the gapped Minkowski embeddings and in the compressible black hole ones. These conductivities depend on the flux and contain a contribution from the dynamical flavors which can be regarded as an effect of intrinsic disorder due to quantum fluctuations of the fundamentals. We present an explicit, analytic family of supersymmetric solutions with nonzero charge density, electric, and magnetic fields.

  19. Flux and Hall states in ABJM with dynamical flavors

    Science.gov (United States)

    Bea, Yago; Jokela, Niko; Lippert, Matthew; Ramallo, Alfonso V.; Zoakos, Dimitrios

    2015-03-01

    We study the physics of probe D6-branes with quantized internal worldvolume flux in the ABJM background with unquenched massless flavors. This flux breaks parity in the (2+1)-dimensional gauge theory and allows quantum Hall states. Parity breaking is also explicitly demonstrated via the helicity dependence of the meson spectrum. We obtain general expressions for the conductivities, both in the gapped Minkowski embeddings and in the compressible black hole ones. These conductivities depend on the flux and contain a contribution from the dynamical flavors which can be regarded as an effect of intrinsic disorder due to quantum fluctuations of the fundamentals. We present an explicit, analytic family of supersymmetric solutions with nonzero charge density, electric, and magnetic fields.

  20. 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

  1. Dynamics of the formation of the condensed phase particles at detonation of high explosives

    CERN Document Server

    Evdokov, O V; Kulipanov, G N; Luckjanchikov, L A; Lyakhov, N Z; Mishnev, S I; Sharafutdinov, M R; Sheromov, M A; Ten, K A; Titov, V M; Tolochko, B P; Zubkov, P I

    2001-01-01

    The article presents the results of the experimental study SAXS on condensed carbon particles that appear at the detonation of a high explosive. It was shown that the SAXS signal rises for 1.5-4 mu s after the detonation front passing. The SAXS signal in trotyl and its alloys with hexogen starts just after the compression of the material in the detonation wave. In octogen, hexogen and PETN, the SAXS signal appears in 0.5 mu s and is much smaller than the signal at the detonation of trotyl and its alloys with hexogen.

  2. 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

  3. Computational model of exploding metallic fuses for multimegajoule switching

    International Nuclear Information System (INIS)

    Lindemuth, I.R.; Brownell, J.H.; Greene, A.E.; Nickel, G.H.; Oliphant, T.A.; Weiss, D.L.

    1985-01-01

    A new model for determining the time-dependent behavior of exploding metallic fuses is formulated. The model draws on an atomic data base and gives insight into the temporal behavior of the material density and temperature of the fuse as well as the nonlinear electrical circuit interaction. The model includes an embedding insulating tamper and leads to a plausible explanation of fuse ''restrike.'' The model predicts time-scale compression of 500 for inductive store systems powered by explosive driven magnetic flux compression generators. A scenario for achieving multimegajoule foil implosions is predicted

  4. 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.

  5. 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.

  6. Lossless compression of waveform data for efficient storage and transmission

    International Nuclear Information System (INIS)

    Stearns, S.D.; Tan, Li Zhe; Magotra, Neeraj

    1993-01-01

    Compression of waveform data is significant in many engineering and research areas since it can be used to alleviate data storage and transmission bandwidth. For example, seismic data are widely recorded and transmitted so that analysis can be performed on large amounts of data for numerous applications such as petroleum exploration, determination of the earth's core structure, seismic event detection and discrimination of underground nuclear explosions, etc. This paper describes a technique for lossless wave form data compression. The technique consists of two stages. The first stage is a modified form of linear prediction with discrete coefficients and the second stage is bi-level sequence coding. The linear predictor generates an error or residue sequence in a way such that exact reconstruction of the original data sequence can be accomplished with a simple algorithm. The residue sequence is essentially white Gaussian with seismic or other similar waveform data. Bi-level sequence coding, in which two sample sizes are chosen and the residue sequence is encoded into subsequences that alternate from one level to the other, further compresses the residue sequence. The principal feature of the two-stage data compression algorithm is that it is lossless, that is, it allows exact, bit-for-bit recovery of the original data sequence. The performance of the lossless compression algorithm at each stage is analyzed. The advantages of using bi-level sequence coding in the second stage are its simplicity of implementation, its effectiveness on data with large amplitude variations, and its near-optimal performance in encoding Gaussian sequences. Applications of the two-stage technique to typical seismic data indicates that an average number of compressed bits per sample close to the lower bound is achievable in practical situations

  7. 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

  8. Behavior of surface residual stress in explosion hardened high manganese austenitic cast steel due to repeated impact loads

    International Nuclear Information System (INIS)

    Oda, Akira; Miyagawa, Hideaki

    1985-01-01

    Explosion hardened high manganese austenitic cast steel is being tried for rail crossing recently. From the previous studies, it became clear that high tensile residual stress was generated in the hardened surface layer by explosion and microcracks were observed. In this study, therefore, the behavior of surface residual stress in explosion hardened steel due to repeated impact loads was examined and compared with those of the original and shot peened steels. The results obtained are summarized as follows: (1) In the initial stage of the repetition of impact, high tensile surface residual stress in explosion hardened steel decreased rapidly with the repetition of impact, while those of the original and shot peened steels increased rapidly. This difference was attributed to the difference in depth of the work hardened layer in three testing materials. (2) Beyond 20 impacts the residual stress of three test specimens decreased gradually, and at more than 2000 impacts the compressive stress of about 500 MPa was produced regardless of the histories of working of testing materials. (3) The linear law in the second stage of residual stress fading was applicable to this case, and the range of the linear relationship was related to the depth of the work hardened layer of testing material. (4) From the changes in half-value breadth and peak intensity of diffraction X-ray, it was supposed that a peculiar microscopic strain exists in explosion hardened steel. (author)

  9. Shallow magma diversions during explosive maar-diatreme eruptions in mafic volcanic fields

    Science.gov (United States)

    Le Corvec, N.; Muirhead, J.; White, J. D. L.

    2017-12-01

    Maar-diatremes are inverted conical structures formed by subterranean excavation and remobilization of country rocks during explosive volcanism and common in mafic volcanic fields. We focus on impacts of excavation and filling of maar-diatremes on the local state of stress, and its subsequent influence on underlying feeder dikes, which are critical for understanding the development of intrusive networks that feed surface eruptions. We address this issue using finite element models in COMSOL Multiphysics®. Inverted conical structures of varying sizes are excavated in a gravitationally loaded elastic half-space, and then progressively filled with volcaniclastic material, resulting in changes in the orientations and magnitudes of stresses generated within surrounding rocks and within the filling portion of the maar-diatreme. Our results show that rapid unloading during maar-diatreme excavation generates a horizontal compressive stress state beneath diatremes. These stresses allow magma to divert laterally as saucer-shaped sills and circumferential dikes at varying depths in the shallow feeder system, and produce intrusion geometries consistent with both field observations from exhumed volcanic fields and conceptual models of diatreme growth. Stresses generated in these models also provide an explanation for the evolving locations of fragmentation zones over the course of diatreme's filling. In particular, results from this study suggest that: (1) extensional stresses at the base of the diatreme fill favor magma ascent in the lower half of the structure, and possibly promote volatile exsolution and magma fragmentation; and (2) increased filling of diatremes creates a shallow compressive stress state that can inhibit magma ascent to the surface, promoting widespread intra-diatreme explosions, efficient mixing of host rock, and upward widening of the diatreme structure.

  10. 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 ...

  11. 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.

  12. 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.

  13. Laser driven single shock compression of fluid deuterium from 45 to 220 GPa

    Energy Technology Data Exchange (ETDEWEB)

    Hicks, D; Boehly, T; Celliers, P; Eggert, J; Moon, S; Meyerhofer, D; Collins, G

    2008-03-23

    The compression {eta} of liquid deuterium between 45 and 220 GPa under laser-driven shock loading has been measured using impedance matching to an aluminum (Al) standard. An Al impedance match model derived from a best fit to absolute Hugoniot data has been used to quantify and minimize the systematic errors caused by uncertainties in the high-pressure Al equation of state. In deuterium below 100 GPa results show that {eta} {approx_equal} 4.2, in agreement with previous impedance match data from magnetically-driven flyer and convergent-explosive shock wave experiments; between 100 and 220 GPa {eta} reaches a maximum of {approx}5.0, less than the 6-fold compression observed on the earliest laser-shock experiments but greater than expected from simple extrapolations of lower pressure data. Previous laser-driven double-shock results are found to be in good agreement with these single-shock measurements over the entire range under study. Both sets of laser-shock data indicate that deuterium undergoes an abrupt increase in compression at around 110 GPa.

  14. Pressure correction schemes for compressible flows: application to baro-tropic Navier-Stokes equations and to drift-flux model

    International Nuclear Information System (INIS)

    Gastaldo, L.

    2007-11-01

    We develop in this PhD thesis a simulation tool for bubbly flows encountered in some late phases of a core-melt accident in pressurized water reactors, when the flow of molten core and vessel structures comes to chemically interact with the concrete of the containment floor. The physical modelling is based on the so-called drift-flux model, consisting of mass balance and momentum balance equations for the mixture (Navier-Stokes equations) and a mass balance equation for the gaseous phase. First, we propose a pressure correction scheme for the compressible Navier-Stokes equations based on mixed non-conforming finite elements. An ad hoc discretization of the advection operator, by a finite volume technique based on a dual mesh, ensures the stability of the velocity prediction step. A priori estimates for the velocity and the pressure yields the existence of the solution. We prove that this scheme is stable, in the sense that the discrete entropy is decreasing. For the conservation equation of the gaseous phase, we build a finite volume discretization which satisfies a discrete maximum principle. From this last property, we deduce the existence and the uniqueness of the discrete solution. Finally, on the basis of these works, a conservative and monotone scheme which is stable in the low Mach number limit, is build for the drift-flux model. This scheme enjoys, moreover, the following property: the algorithm preserves a constant pressure and velocity through moving interfaces between phases (i.e. contact discontinuities of the underlying hyperbolic system). In order to satisfy this property at the discrete level, we build an original pressure correction step which couples the mass balance equation with the transport terms of the gas mass balance equation, the remaining terms of the gas mass balance being taken into account with a splitting method. We prove the existence of a discrete solution for the pressure correction step. Numerical results are presented; they

  15. CHOSEN PROPERTIES OF SANDWICH MATERIAL Ti-304 STAINLESS STEEL AFTER EXPLOSIVE WELDING

    Directory of Open Access Journals (Sweden)

    Dmytro Ostroushko

    2011-05-01

    Full Text Available The work deals with evaluation of joint of stainless steel 304 SS (sheet and commercially pure Ti both after welding explosion and followed-up annealing at 600°C/1.5h/air. The bonding line shows sinusoidal character with curls in crest unlike the trough of the sine curve. The heat treatment does not change the character of the interface. In work amplitude, wave length and the interface thickness were measured. Thickness of compressed cladded matrix of Ti was measured in area of crests and troughs. In crest of joint melted zones were studied, where complex oxides and intermetallic phases were revealed.

  16. 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.

  17. 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

  18. 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.)

  19. 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...

  20. Effect of compression stockings on cutaneous microcirculation: Evaluation based on measurements of the skin thermal conductivity.

    Science.gov (United States)

    Grenier, E; Gehin, C; McAdams, E; Lun, B; Gobin, J-P; Uhl, J-F

    2016-03-01

    To study of the microcirculatory effects of elastic compression stockings. In phlebology, laser Doppler techniques (flux or imaging) are widely used to investigate cutaneous microcirculation. It is a method used to explore microcirculation by detecting blood flow in skin capillaries. Flux and imaging instruments evaluate, non-invasively in real-time, the perfusion of cutaneous micro vessels. Such tools, well known by the vascular community, are not really suitable to our protocol which requires evaluation through the elastic compression stockings fabric. Therefore, we involve another instrument, called the Hematron (developed by Insa-Lyon, Biomedical Sensor Group, Nanotechnologies Institute of Lyon), to investigate the relationship between skin microcirculatory activities and external compression provided by elastic compression stockings. The Hematron measurement principle is based on the monitoring of the skin's thermal conductivity. This clinical study examined a group of 30 female subjects, aged 42 years ±2 years, who suffer from minor symptoms of chronic venous disease, classified as C0s, and C1s (CEAP). The resulting figures show, subsequent to the pressure exerted by elastic compression stockings, an improvement of microcirculatory activities observed in 83% of the subjects, and a decreased effect was detected in the remaining 17%. Among the total population, the global average increase of the skin's microcirculatory activities is evaluated at 7.63% ± 1.80% (p compression stockings has a direct influence on the skin's microcirculation within this female sample group having minor chronic venous insufficiency signs. Further investigations are required for a deeper understanding of the elastic compression stockings effects on the microcirculatory activity in venous diseases at other stages of pathology. © The Author(s) 2014.

  1. 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

  2. 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.

  3. 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.

  4. 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)

  5. 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

  6. Investigation of turbulence models with compressibility corrections for hypersonic boundary flows

    Directory of Open Access Journals (Sweden)

    Han Tang

    2015-12-01

    Full Text Available The applications of pressure work, pressure-dilatation, and dilatation-dissipation (Sarkar, Zeman, and Wilcox models to hypersonic boundary flows are investigated. The flat plate boundary layer flows of Mach number 5–11 and shock wave/boundary layer interactions of compression corners are simulated numerically. For the flat plate boundary layer flows, original turbulence models overestimate the heat flux with Mach number high up to 10, and compressibility corrections applied to turbulence models lead to a decrease in friction coefficients and heating rates. The pressure work and pressure-dilatation models yield the better results. Among the three dilatation-dissipation models, Sarkar and Wilcox corrections present larger deviations from the experiment measurement, while Zeman correction can achieve acceptable results. For hypersonic compression corner flows, due to the evident increase of turbulence Mach number in separation zone, compressibility corrections make the separation areas larger, thus cannot improve the accuracy of calculated results. It is unreasonable that compressibility corrections take effect in separation zone. Density-corrected model by Catris and Aupoix is suitable for shock wave/boundary layer interaction flows which can improve the simulation accuracy of the peak heating and have a little influence on separation zone.

  7. 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...

  8. 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

  9. 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.

  10. Could a nearby supernova explosion have caused a mass extinction?

    Science.gov (United States)

    Ellis, J; Schramm, D N

    1995-01-03

    We examine the possibility that a nearby supernova explosion could have caused one or more of the mass extinctions identified by paleontologists. We discuss the possible rate of such events in the light of the recent suggested identification of Geminga as a supernova remnant less than 100 parsec (pc) away and the discovery of a millisecond pulsar about 150 pc away and observations of SN 1987A. The fluxes of gamma-radiation and charged cosmic rays on the Earth are estimated, and their effects on the Earth's ozone layer are discussed. A supernova explosion of the order of 10 pc away could be expected as often as every few hundred million years and could destroy the ozone layer for hundreds of years, letting in potentially lethal solar ultraviolet radiation. In addition to effects on land ecology, this could entail mass destruction of plankton and reef communities, with disastrous consequences for marine life as well. A supernova extinction should be distinguishable from a meteorite impact such as the one that presumably killed the dinosaurs at the "KT boundary." The recent argument that the KT event was exceedingly large and thus quite rare supports the need for other catastrophic events.

  11. Z a Fast Pulsed Power Generator for Ultra-High Magnetic Field Generation

    Science.gov (United States)

    Spielman, R. B.; Stygar, W. A.; Struve, K. W.; Asay, J. R.; Hall, C. A.; Bernard, M. A.; Bailey, J. E.; McDaniel, D. H.

    2004-11-01

    Advances in fast, pulsed-power technologies have resulted in the development of very high current drivers that have current rise times ~100 ns. The largest such pulsed power driver today is the new Z accelerator located at Sandia National Laboratories in Albuquerque, New Mexico. Z can deliver more than 20 MA with a time-to-peak of 105 ns to low inductance (~1 nH) loads. Such large drivers are capable of directly generating magnetic fields approaching 3 kT in small, 1 cm3 volumes. In addition to direct field generation, Z can be used to compress an applied, axial seed field with a plasma. Flux compression schemes are not new and are, in fact, the basis of all explosive flux-compression generators, but we propose the use of plasma armatures rather than solid, conducting armatures. We present experimental results from the Z accelerator in which magnetic fields of ~2 kT are generated and measured with several diagnostics. Issues such as energy loss in solid conductors and dynamic response of current-carrying conductors to very large magnetic fields are reviewed in context with Z experiments. We describe planned flux-compression experiments that are expected to create the highest-magnitude uniform-field volumes yet attained in the laboratory.

  12. 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.

  13. A direct Eulerian method for the simulation of multi-material compressible flows with material sliding

    International Nuclear Information System (INIS)

    Motte, R.; Braeunig, J.P.; Peybernes, M.

    2012-01-01

    As the simulation of compressible flows with several materials is essential for applications studied within the CEA-DAM, the authors propose an approach based on finite volumes with centred variables for the resolution of compressible Euler equations. Moreover, they allow materials to slide with respect to each other as it is the case for water and air, for example. A conservation law is written for each material in a hybrid grid, and a condition of contact between materials under the form of fluxes is expressed. It is illustrated by the case of an intense shock propagating in water and interacting with an air bubble which will be strongly deformed and compressed

  14. Magnetic compression into Brillouin flow

    International Nuclear Information System (INIS)

    Becker, R.

    1977-01-01

    The trajectories of beam edge electrons are calculated in the transition region between an electrostatic gun and an increasing magnetic field for various field shapes, transition length, and cathode fluxes, assuming that the resultant beam is of Brillouin flow type. The results give a good physical interpretation to the axial gradient of the magnetic field being responsible for the amount of magnetic compression and also for the proper injection conditions. Therefore it becomes possible to predict from the known characteristics of any fairly laminary electrostatic gun the necessary axial gradient of the magnetic field and the axial position of the gun with respect to the field build-up. (orig.) [de

  15. 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

  16. 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

  17. ENTROPIES AND FLUX-SPLITTINGS FOR THE ISENTROPIC EULER EQUATIONS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The authors establish the existence of a large class of mathematical entropies (the so-called weak entropies) associated with the Euler equations for an isentropic, compressible fluid governed by a general pressure law. A mild assumption on the behavior of the pressure law near the vacuum is solely required. The analysis is based on an asymptotic expansion of the fundamental solution (called here the entropy kernel) of a highly singular Euler-Poisson-Darboux equation. The entropy kernel is only H lder continuous and its regularity is carefully investigated. Relying on a notion introduced earlier by the authors, it is also proven that, for the Euler equations, the set of entropy flux-splittings coincides with the set of entropies-entropy fluxes. These results imply the existence of a flux-splitting consistent with all of the entropy inequalities.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. A study of binder materials subjected to isentropic compression loading

    International Nuclear Information System (INIS)

    Hall, Clint Allen; Orler, E. Bruce; Sheffield, Steve A.; Gustavsen, Rick L.; Sutherland, Gerrit; Baer, Melvin R.; Hooks, D.E.

    2005-01-01

    Binders such as Estane, Teflon, Kel F and HTPB are typically used in heterogeneous explosives to bond polycrystalline constituents together as an energetic composite. Combined theoretical and experimental studies are underway to unravel the mechanical response of these materials when subjected to isentropic compression loading. Key to this effort is the determination of appropriate constitutive and EOS property data at extremely high stress-strain states as required for detailed mesoscale modeling. The Sandia Z accelerator and associated diagnostics provides new insights into mechanical response of these nonreactive constituents via isentropic ramp-wave compression loading. Several thicknesses of samples, varied from 0.3 to 1.2 mm, were subjected to a ramp load of ∼42 Kbar over 500 ns duration using the Sandia Z-machine. Profiles of transmitted ramp waves were measured at window interfaces using conventional VISAR. Shock physics analysis is then used to determine the nonlinear material response of the binder materials. In this presentation we discuss experimental and modeling details of the ramp wave loading ICE experiments designed specifically for binder materials.

  3. In-situ Raman spectroscopy and high-speed photography of a shocked triaminotrinitrobenzene based explosive

    Energy Technology Data Exchange (ETDEWEB)

    Saint-Amans, C.; Hébert, P., E-mail: philippe.hebert@cea.fr; Doucet, M. [CEA, DAM, Le RIPAULT, F-37620 Monts (France); Resseguier, T. de [Institut P' , UPR CNRS 3346, ENSMA, Université de Poitiers, F-86961 Futuroscope, Chasseneuil (France)

    2015-01-14

    We have developed a single-shot Raman spectroscopy experiment to study at the molecular level the initiation mechanisms that can lead to sustained detonation of a triaminotrinitrobenzene-based explosive. Shocks up to 30 GPa were generated using a two-stage laser-driven flyer plate generator. The samples were confined by an optical window and shock pressure was maintained for at least 30 ns. Photon Doppler Velocimetry measurements were performed at the explosive/window interface to determine the shock pressure profile. Raman spectra were recorded as a function of shock pressure and the shifts of the principal modes were compared to static high-pressure measurements performed in a diamond anvil cell. Our shock data indicate the role of temperature effects. Our Raman spectra also show a progressive extinction of the signal which disappears around 9 GPa. High-speed photography images reveal a simultaneous progressive darkening of the sample surface up to total opacity at 9 GPa. Reflectivity measurements under shock compression show that this opacity is due to a broadening of the absorption spectrum over the entire visible region.

  4. 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)

  5. 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.

  6. 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.

  7. Conduit Stability and Collapse in Explosive Volcanic Eruptions: Coupling Conduit Flow and Failure Models

    Science.gov (United States)

    Mullet, B.; Segall, P.

    2017-12-01

    Explosive volcanic eruptions can exhibit abrupt changes in physical behavior. In the most extreme cases, high rates of mass discharge are interspaced by dramatic drops in activity and periods of quiescence. Simple models predict exponential decay in magma chamber pressure, leading to a gradual tapering of eruptive flux. Abrupt changes in eruptive flux therefore indicate that relief of chamber pressure cannot be the only control of the evolution of such eruptions. We present a simplified physics-based model of conduit flow during an explosive volcanic eruption that attempts to predict stress-induced conduit collapse linked to co-eruptive pressure loss. The model couples a simple two phase (gas-melt) 1-D conduit solution of the continuity and momentum equations with a Mohr-Coulomb failure condition for the conduit wall rock. First order models of volatile exsolution (i.e. phase mass transfer) and fragmentation are incorporated. The interphase interaction force changes dramatically between flow regimes, so smoothing of this force is critical for realistic results. Reductions in the interphase force lead to significant relative phase velocities, highlighting the deficiency of homogenous flow models. Lateral gas loss through conduit walls is incorporated using a membrane-diffusion model with depth dependent wall rock permeability. Rapid eruptive flux results in a decrease of chamber and conduit pressure, which leads to a critical deviatoric stress condition at the conduit wall. Analogous stress distributions have been analyzed for wellbores, where much work has been directed at determining conditions that lead to wellbore failure using Mohr-Coulomb failure theory. We extend this framework to cylindrical volcanic conduits, where large deviatoric stresses can develop co-eruptively leading to multiple distinct failure regimes depending on principal stress orientations. These failure regimes are categorized and possible implications for conduit flow are discussed, including

  8. DNABIT Compress – Genome compression algorithm

    OpenAIRE

    Rajarajeswari, Pothuraju; Apparao, Allam

    2011-01-01

    Data compression is concerned with how information is organized in data. Efficient storage means removal of redundancy from the data being stored in the DNA molecule. Data compression algorithms remove redundancy and are used to understand biologically important molecules. We present a compression algorithm, “DNABIT Compress” for DNA sequences based on a novel algorithm of assigning binary bits for smaller segments of DNA bases to compress both repetitive and non repetitive DNA sequence. Our ...

  9. Morphing continuum analysis of energy transfer in compressible turbulence

    Science.gov (United States)

    Cheikh, Mohamad Ibrahim; Wonnell, Louis B.; Chen, James

    2018-02-01

    A shock-preserving finite volume solver with the generalized Lax-Friedrichs splitting flux for morphing continuum theory (MCT) is presented and verified. The numerical MCT solver is showcased in a supersonic turbulent flow with Mach 2.93 over an 8∘ compression ramp. The simulation results validated MCT with experiments as an alternative for modeling compressible turbulence. The required size of the smallest mesh cell for the MCT simulation is shown to be almost an order larger than that in a similar direct numerical simulation study. The comparison shows MCT is a much more computationally friendly theory than the classical Navier-Stokes equations. The dynamics of energy cascade at the length scale of individual eddies is illuminated through the subscale rotation introduced by MCT. In this regard, MCT provides a statistical averaging procedure for capturing energy transfer in compressible turbulence, not found in classical fluid theories. Analysis of the MCT results show the existence of a statistical coupling of the internal and translational kinetic energy fluctuations with the corresponding eddy rotational energy fluctuations, indicating a multiscale transfer of energy. In conclusion, MCT gives a new characterization of the energy cascade within compressible turbulence without the use of excessive computational resources.

  10. Gas-Kinetic Theory Based Flux Splitting Method for Ideal Magnetohydrodynamics

    Science.gov (United States)

    Xu, Kun

    1998-01-01

    A gas-kinetic solver is developed for the ideal magnetohydrodynamics (MHD) equations. The new scheme is based on the direct splitting of the flux function of the MHD equations with the inclusion of "particle" collisions in the transport process. Consequently, the artificial dissipation in the new scheme is much reduced in comparison with the MHD Flux Vector Splitting Scheme. At the same time, the new scheme is compared with the well-developed Roe-type MHD solver. It is concluded that the kinetic MHD scheme is more robust and efficient than the Roe- type method, and the accuracy is competitive. In this paper the general principle of splitting the macroscopic flux function based on the gas-kinetic theory is presented. The flux construction strategy may shed some light on the possible modification of AUSM- and CUSP-type schemes for the compressible Euler equations, as well as to the development of new schemes for a non-strictly hyperbolic system.

  11. 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.

  12. 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.

  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. A study on damage effect from boiling liquid expanding vapor explosion(Believe) of LPG charging facility

    Energy Technology Data Exchange (ETDEWEB)

    Roh, Sam Kew; Ham, Eun Gu [Dept. of Architectural Engineering, Kwangwoon University (Korea); Kim, Tae Hwan [Automation System Research Institute, Seoul (Korea)

    1999-12-01

    The LPG refueling station's explosion at Bucheon city was a major accident which with rare frequency of occurrence and large damage effect. Therefore, to prevent similar accident in the future from LPG charging stations which located in urban area. It needs to identify the damage effects of such facilities by comparing theoretically quantities risk and actual damage. The BLEVE effects from the accident showed similar damage effect in case of heat flux, however, the overpressure level reflected at the reduced distance by 15%. The structure damage to the near by area showed comparatively large heat radiation damage to the concrete structure strength and shape changes through heat flux while the overpressure effect was small. 13 refs., 4 figs., 4 tabs.

  15. Nonoscillatory shock capturing scheme using flux limited dissipation

    International Nuclear Information System (INIS)

    Jameson, A.

    1985-01-01

    A method for modifying the third order dissipative terms by the introduction of flux limiters is proposed. The first order dissipative terms can then be eliminated entirely, and in the case of a scalar conservation law the scheme is converted into a total variation diminishing scheme provided that an appropriate value is chosen for the dissipative coefficient. Particular attention is given to: (1) the treatment of the scalar conservation law; (2) the treatment of the Euler equations for inviscid compressible flow; (3) the boundary conditions; and (4) multistage time stepping and multigrid schemes. Numerical results for transonic flows suggest that a central difference scheme augmented by flux limited dissipative terms can lead to an effective nonoscillatory shock capturing method. 20 references

  16. Computation of compressible quasi-axisymmetric slender vortex flow and breakdown

    Science.gov (United States)

    Kandil, Osama A.; Kandil, Hamdy A.

    1991-01-01

    The unsteady, compressible Navier-Stokes equations are used to compute and analyze compressible quasi-axisymmetric isolated vortices. The Navier-Stokes equations are solved using an implicit, upwind, flux difference splitting finite volume scheme. The developed three dimensional solver was verified by comparing its solution profiles with those of a slender, quasi-axisymmetric vortex solver for a subsonic, quasi-axisymmetric vortex in an unbounded domain. The Navier-Stokes solver is then used to solve for a supersonic, quasi-axisymmetric vortex flow in a configured circular duct. Steady and unsteady vortex-shock interactions and breakdown were captured. The problem was also calculated using the Euler solver of the same code; the results were compared with those of the Navier-Stokes solver. The effect of the initial swirl was investigated.

  17. 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

  18. 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...

  19. 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.

  20. Flow and Heat Transfer Characteristics of Turbulent Gas Flow in Microtube with Constant Heat Flux

    International Nuclear Information System (INIS)

    Hong, Chungpyo; Matsushita, Shinichi; Ueno, Ichiro; Asako, Yutaka

    2012-01-01

    Local friction factors for turbulent gas flows in circular microtubes with constant wall heat flux were obtained numerically. The numerical methodology is based on arbitrary-Lagrangian-Eulerian method to solve two-dimensional compressible momentum and energy equations. The Lam-Bremhorst's Low-Reynolds number turbulence model was employed to calculate eddy viscosity coefficient and turbulence energy. The simulations were performed for a wide flow range of Reynolds numbers and Mach numbers with different constant wall heat fluxes. The stagnation pressure was chosen in such a way that the outlet Mach number ranged from 0.07 to 1.0. Both Darcy friction factor and Fanning friction factor were locally obtained. The result shows that the obtained both friction factors were evaluated as a function of Reynolds number on the Moody chart. The values of Darcy friction factor differ from Blasius correlation due to the compressibility effects but the values of Fanning friction factor almost coincide with Blasius correlation. The wall heat flux varied from 100 to 10000 W/m 2 . The wall and bulk temperatures with positive heat flux are compared with those of incompressible flow. The result shows that the Nusselt number of turbulent gas flow is different from that of incompressible flow.

  1. 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)

  2. Chemically reacting flow of a compressible thermally radiating two-component plasma

    International Nuclear Information System (INIS)

    Bestman, A.R.

    1990-12-01

    The paper studies the compressible flow of a hot two-component plasma in the presence of gravitation and chemical reaction in a vertical channel. For the optically thick gas approximation, closed form analytical solutions are possible. Asymptotic solutions are also obtained for the general differential approximation when the temperature of the two bounding walls are the same. In the general case the problem is reduced to the solution of standard nonlinear integral equations which can be tackled by iterative procedure. The results are discussed quantitatively. The problem may be applicable to the understanding of explosive hydrogen-burning model of solar flares. (author). 6 refs, 4 figs

  3. Fractal Loop Heat Pipe Performance Comparisons of a Soda Lime Glass and Compressed Carbon Foam Wick

    Science.gov (United States)

    Myre, David; Silk, Eric A.

    2014-01-01

    This study compares heat flux performance of a Loop Heat Pipe (LHP) wick structure fabricated from compressed carbon foam with that of a wick structure fabricated from sintered soda lime glass. Each wick was used in an LHP containing a fractal based evaporator. The Fractal Loop Heat Pipe (FLHP) was designed and manufactured by Mikros Manufacturing Inc. The compressed carbon foam wick structure was manufactured by ERG Aerospace Inc., and machined to specifications comparable to that of the initial soda lime glass wick structure. Machining of the compressed foam as well as performance testing was conducted at the United States Naval Academy. Performance testing with the sintered soda lime glass wick structures was conducted at NASA Goddard Space Flight Center. Heat input for both wick structures was supplied via cartridge heaters mounted in a copper block. The copper heater block was placed in contact with the FLHP evaporator which had a circular cross-sectional area of 0.88 cm(sup 2). Twice distilled, deionized water was used as the working fluid in both sets of experiments. Thermal performance data was obtained for three different Condenser/Subcooler temperatures under degassed conditions. Both wicks demonstrated comparable heat flux performance with a maximum of 75 W/cm observed for the soda lime glass wick and 70 W /cm(sup 2) for the compressed carbon foam wick.

  4. 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...

  5. Development of ab initio techniques critical for future science-based explosives R&D

    Energy Technology Data Exchange (ETDEWEB)

    Wixom, Ryan R. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Mattsson, Ann Elisabet [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2013-10-01

    Density Functional Theory (DFT) has emerged as an indispensable tool in materials research, since it can accurately predict properties of a wide variety of materials at both equilibrium and extreme conditions. However, for organic molecular crystal explosives, successful application of DFT has largely failed due to the inability of current exchange-correlation functionals to correctly describe intermolecular van der Waals (vdWs) forces. Despite this, we have discovered that even with no treatment of vdWs bonding, the AM05 functional and DFT based molecular dynamics (MD) could be used to study the properties of molecular crystals under compression. We have used DFT-MD to predict the unreacted Hugoniots for PETN and HNS and validated the results by comparison with crystalline and porous experimental data. Since we are also interested in applying DFT methods to study the equilibrium volume properties of explosives, we studied the nature of the vdWs bonding in pursuit of creating a new DFT functional capable of accurately describing equilibrium bonding of molecular crystals. In this report we discuss our results for computing shock Hugoniots of molecular crystals and also what was learned about the nature of bonding in these materials.

  6. ESE a 2D compressible multiphase flow code developed for MFCI analysis - code validation

    International Nuclear Information System (INIS)

    Leskovar, M.; Mavko, B.

    1998-01-01

    ESE (Evaluation of Steam Explosions) is a general second order accurate two-dimensional compressible multiphase flow computer code. It has been developed to model the interaction of molten core debris with water during the first premixing stage of a steam explosion. A steam explosion is a physical event, which may occur during a severe reactor accident following core meltdown when the molten fuel comes into contact with the coolant water. Since the exchanges of mass, momentum and energy are regime dependent, different exchange laws have been incorporated in ESE for the major flow regimes. With ESE a number of premixing experiments performed at the Oxford University and at the QUEOS facility at Forschungszentrum Karlsruhe has been simulated. In these premixing experiments different jets of spheres were injected in a water poll. The ESE validation plan was carefully chosen, starting from very simple, well-defined problems, and gradually working up to more complicated ones. The results of ESE simulations, which were compared to experimental data and also to first order accurate calculations, are presented in form graphs. Most of the ESE results agree qualitatively as quantitatively reasonably well with experimental data and in general better than the results obtained with the first order accurate calculation.(author)

  7. 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

  8. Increased rates of large‐magnitude explosive eruptions in Japan in the late Neogene and Quaternary

    Science.gov (United States)

    Sparks, R. S. J.; Wallace, L. M.; Engwell, S. L.; Scourse, E. M.; Barnard, N. H.; Kandlbauer, J.; Brown, S. K.

    2016-01-01

    Abstract Tephra layers in marine sediment cores from scientific ocean drilling largely record high‐magnitude silicic explosive eruptions in the Japan arc for up to the last 20 million years. Analysis of the thickness variation with distance of 180 tephra layers from a global data set suggests that the majority of the visible tephra layers used in this study are the products of caldera‐forming eruptions with magnitude (M) > 6, considering their distances at the respective drilling sites to their likely volcanic sources. Frequency of visible tephra layers in cores indicates a marked increase in rates of large magnitude explosive eruptions at ∼8 Ma, 6–4 Ma, and further increase after ∼2 Ma. These changes are attributed to major changes in tectonic plate interactions. Lower rates of large magnitude explosive volcanism in the Miocene are related to a strike‐slip‐dominated boundary (and temporary cessation or deceleration of subduction) between the Philippine Sea Plate and southwest Japan, combined with the possibility that much of the arc in northern Japan was submerged beneath sea level partly due to previous tectonic extension of northern Honshu related to formation of the Sea of Japan. Changes in plate motions and subduction dynamics during the ∼8 Ma to present period led to (1) increased arc‐normal subduction in southwest Japan (and resumption of arc volcanism) and (2) shift from extension to compression of the upper plate in northeast Japan, leading to uplift, crustal thickening and favorable conditions for accumulation of the large volumes of silicic magma needed for explosive caldera‐forming eruptions. PMID:27656115

  9. 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.

  10. Generation of thermonuclear fusion neutrons by means of a pure explosion. Part 2. Experimental results

    International Nuclear Information System (INIS)

    Derentowicz, H.; Kaliski, S.; Wolski, J.; Ziolkowski, Z.

    1977-01-01

    This paper presents the experimental results of the generation of a thermonuclear fusion neutrons by means of explosion. The experimental set is based on a quasi-spherical experiment in which a polyethylene layer is shot into a conic region hollowed out in a golden target and filled with deuterium gas. The speeding-up system is based on shooting the conic liner onto the surface of the Cu cone in which the Mach wave is generated and propagates along the cone axis leading to an implosion velocity of the polyethylene layer of the order of (4 - 5).10 6 cm/s. This affords a 10 3 -multiple compression of the D 2 gas (p 0 approximately 1.2 atm) and a neutron emission of the order of 3.10 7 from a mass of about 10 -7 g. This result is in full agreement with theoretical estimates. This is the first published and documented experiment in which a neutron stream of thermonuclear fusion was obtained by means of a pure explosion. (author)

  11. Study on minimum heat-flux point during boiling heat transfer on horizontal plates

    International Nuclear Information System (INIS)

    Nishio, Shigefumi

    1985-01-01

    The characteristics of boiling heat transfer are usually shown by the boiling curve of N-shape having the maximum and minimum points. As for the limiting heat flux point, that is, the maximum point, there have been many reports so far, as it is related to the physical burn of heat flux-controlling type heating surfaces. But though the minimum heat flux point is related to the quench point as the problems in steel heat treatment, the core safety of LWRs, the operational stability of superconducting magnets, the start-up characteristics of low temperature machinery, the condition of vapor explosion occurrence and so on, the systematic information has been limited. In this study, the effects of transient property and the heat conductivity of heating surfaces on the minimum heat flux condition in the pool boiling on horizontal planes were experimentally examined by using liquid nitrogen. The experimental apparatuses for steady boiling, for unsteady boiling with a copper heating surface, and for unsteady boiling with a heating surface other than copper were employed. The boiling curves obtained with these apparatuses and the minimum heat flux point condition are discussed. (Kako, I.)

  12. A test of the comet hypothesis of the Tunguska Meteor Fall - Nature of the meteor 'thermal' explosion paradox

    Science.gov (United States)

    Liu, V. C.

    1978-01-01

    The hypothesis that a comet was responsible for the Tunguska Meteor Fall is rejected because the hypothesis does not seem to account for the intense terminal spherical shock. A porous meteoroid model is proposed, and an analysis indicates that an entity of this type might produce an aerodynamic heat flux large enough to account for the terminal meteor explosion. It is suggested that the presence of olivine and of highly irregular macrostructure in meteors might indicate the presence of some porosity. For a highly porous meteoroid, it is postulated that during entry into the atmosphere the aerodynamic heat transfer at its external or pore walls would become so intensified as to cause either complete ablation with popping or a solid-liquid-vapor phase transition accompanied by an explosion.

  13. 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.

  14. Study of instantaneous unsteady heat transfer in a rapid compression-expansion machine using zero dimensional k- ε turbulence model

    International Nuclear Information System (INIS)

    Bakhshan, Y.; Karim, G. A.; Mansouri, S. H.

    2003-01-01

    In this investigation, the instantaneous unsteady heat transfer within a pneumatically driven rapid compression-expansion machine that offers simple, well-controlled and known boundary conditions was studied. Values of the instantaneous apparent overall heat flux from the cylinder gas to the wall surfaces were calculated using a thermodynamics analysis of the experimentally measured pressure and volume temporal development. Corresponding heat flux values were also calculated through the application of a zero-dimensional k- ε turbulence model the characteristic velocity is a contribution of turbulence kinetic energy, mean kinetic energy of charged air into cylinder and piston motion for the calculation of Reynolds, Nusselt and Prandtl numbers. Comparison of the zero-dimensional k- ε turbulence model prediction with experimental data shows good agreement for all compression ratios

  15. Could a nearby supernova explosion have caused a mass extinction?

    International Nuclear Information System (INIS)

    Ellis, J.; Schramm, D.N.

    1995-01-01

    We examine the possibility that a nearby supernova explosion could have caused one or more of the mass extinctions identified by paleontologists. We discuss the possible rate of such events in the light of the recent suggested identification of Geminga as a supernova remnant less than 100 parsec (pc) away and the discovery of a millisecond pulsar about 150 pc away and observations of SN 1987A. The fluxes of γ-radiation and charged cosmic rays on the Earth are estimated, and their effects on the Earth's ozone layer are discussed. A supernova explosion of the order of 10 pc away could be expected as often as every few hundred million years and could destroy the ozone layer for hundreds of years, letting in potentially lethal solar ultraviolet radiation. In addition to effects on land ecology, this could entail mass destruction of plankton and reef communities, with disastrous consequences for marine life as well. A supernova extinction should be distinguishable from a meteorite impact such as the one that presumably killed the dinosaurs at the open-quotes KT boundary.close quotes The recent argument that the KT event was exceedingly large and thus quite rare supports the need for other catastrophic events. 24 refs

  16. 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.

  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. 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.

  19. Vulcanian explosions at Volcán de Colima, Mexico: modelling the conduit processes

    Science.gov (United States)

    Varley, N. R.; Stevenson, J.; Johnson, J.; Reyes, G.; Weber, K.; Sanderson, R.

    2006-12-01

    Activity at Volcán de Colima has increased over the past 8 years, and is possibly building towards a significant eruption. Monitoring its current activity is therefore critical, with recent expansion of the network providing new types of data which need to be understood. Recent activity has consisted of 3 effusive episodes lasting up to 22 months, separated by periods characterised by daily Vulcanian eruptions of small to moderate size; the largest producing pyroclastic flows reaching over 5 km, representing the most significant since the last Plinian event (1913). A model has been proposed to explain the mechanism of the Vulcanian explosions, derived through integrating different data including seismicity, SO2 flux and the ascent velocity and thermal emission of the eruption column. Infrasound measurements have helped to demonstrate the variability in the distribution of energy produced by the events. Swarms of low frequency seismic events were associated with the largest magnitude explosions and have been examined statistically with variations observed in the magnitude-frequency relationship of each swarm and their distribution. Seismic evidence of migration of the source has been identified, maybe explained by brittle fracturing associated with an increasing pressure differential within the conduit system. Volcán de Colima has a complex edifice structure with explosions switching between multiple vents and showing pulsing. Variation in remotely monitored fumarole temperatures has also been related to the explosive activity. It is clear that small variations of certain critical factors within the conduit system can lead to a transition between effusive and explosive activity. Frequent transitions at Volcán de Colima provide an ideal opportunity to analyse variations in the observable signals and deduce relationships with changes within the conduit that influence magma ascent and degassing, such as its volatile contents or ascent velocity. One goal of this

  20. 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.

  1. 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.

  2. 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)

  3. 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

  4. On the low pressure shock initiation of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine based plastic bonded explosives

    Science.gov (United States)

    Vandersall, Kevin S.; Tarver, Craig M.; Garcia, Frank; Chidester, Steven K.

    2010-05-01

    In large explosive and propellant charges, relatively low shock pressures on the order of 1-2 GPa impacting large volumes and lasting tens of microseconds can cause shock initiation of detonation. The pressure buildup process requires several centimeters of shock propagation before shock to detonation transition occurs. In this paper, experimentally measured run distances to detonation for lower input shock pressures are shown to be much longer than predicted by extrapolation of high shock pressure data. Run distance to detonation and embedded manganin gauge pressure histories are measured using large diameter charges of six octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) based plastic bonded explosives (PBX's): PBX 9404; LX-04; LX-07; LX-10; PBX 9501; and EDC37. The embedded gauge records show that the lower shock pressures create fewer and less energetic "hot spot" reaction sites, which consume the surrounding explosive particles at reduced reaction rates and cause longer distances to detonation. The experimental data is analyzed using the ignition and growth reactive flow model of shock initiation in solid explosives. Using minimum values of the degrees of compression required to ignite hot spot reactions, the previously determined high shock pressure ignition and growth model parameters for the six explosives accurately simulate the much longer run distances to detonation and much slower growths of pressure behind the shock fronts measured during the shock initiation of HMX PBX's at several low shock pressures.

  5. Compressed Natural Gas Vehicle Maintenance Facility Modification Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Kay L. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ramsden, Margo M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gonzales, John E. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lynch, Lauren [National Renewable Energy Lab. (NREL), Golden, CO (United States); Coale, Bob [Gladstein, Neandross & Associates, Santa Monica, CA (United States); Kohout, Jarrod [Gladstein, Neandross & Associates, Santa Monica, CA (United States)

    2017-09-28

    To ensure the safety of personnel and facilities, vehicle maintenance facilities are required by law and by guidelines of the National Fire Protection Association (NFPA) and the International Fire Code (IFC) to exhibit certain design features. They are also required to be fitted with certain fire protection equipment and devices because of the potential for fire or explosion in the event of fuel leakage or spills. All fuels have an explosion or fire potential if specific conditions are present. The hazard presented by liquid fuels, such as gasoline and diesel, results from the spillage of these liquids and subsequent ignition of vapors, causing a fire or explosion. Facilities that maintain liquid-fueled vehicles and implement appropriate safety measures are protected with ventilation systems designed to capture liquid fuel vapors at or near floor level. To minimize the potential for ignition in the event of a spill, receptacles, electrical fixtures, and hot-work operations, such as welding, are located outside of these areas. Compressed natural gas (CNG) is composed of methane with slight amounts of heavier simple hydrocarbons. Maintenance facilities that maintain CNG vehicles indoors must be protected against fire and explosion. However, the means of ensuring safety are different from those employed for liquid fuels because of the gaseous nature of methane and the fact that it is lighter than air. Because CNG is lighter than air, a release will rise to the ceiling of the maintenance facility and quickly dissipate rather than remaining at or near floor level like liquid fuel vapors. Although some of the means of protection for CNG vehicle maintenance facilities are similar to those used for liquid-fueled vehicles (ventilation and elimination of ignition sources), the types and placement of the protection equipment are different because of the behavior of the different fuels. The nature of gaseous methane may also require additional safeguards, such as combustible

  6. Impact of surface energy on the shock properties of granular explosives

    Science.gov (United States)

    Bidault, X.; Pineau, N.

    2018-01-01

    This paper presents the first part of a two-fold molecular dynamics study of the impact of the granularity on the shock properties of high explosives. Recent experimental studies show that the granularity can have a substantial impact on the properties of detonation products {i.e., variations in the size distributions of detonation nanodiamonds [V. Pichot et al., Sci. Rep. 3, 2159 (2013)]}. These variations can have two origins: the surface energy, which is a priori enhanced from micro- to nano-scale, and the porosity induced by the granular structure. In this first report, we study the impact of the surface-energy contribution on the inert shock compression of TATB, TNT, α-RDX, and β-HMX nano-grains (triaminotrinitrobenzene, trinitrotoluene, hexogen and octogen, respectively). We compute the radius-dependent surface energy and combine it with an ab initio-based equation of state in order to obtain the resulting shock properties through the Rankine-Hugoniot relations. We find that the enhancement of the surface energy results in a moderate overheating under shock compression. This contribution is minor with respect to porosity, when compared to a simple macroscopic model. This result motivates further atomistic studies on the impact of nanoporosity networks on the shock properties.

  7. Effect of shock pressure on the structure and superconducting properties of Y-Ba-Cu-O in explosively fabricated bulk metal-matrix composites

    Science.gov (United States)

    Murr, L. E.; Niou, C. S.; Pradhan-Advani, M.

    1991-01-01

    While it is now well established that copper-oxide-based power, or virtually any other ceramic superconductor powder, can be consolidated and encapsulated within a metal matrix by explosive consolidation, the erratic superconductivity following fabrication has posed a major problem for bulk applications. The nature of this behavior was found to arise from microstructural damage created in the shock wave front, and the residual degradation in superconductivity was demonstrated to be directly related to the peak shock pressure. The explosively fabricated or shock loaded YBa2Cu3Ox examples exhibit drastically altered rho (or R) - T curves. The deterioration in superconductivity is even more noticeable in the measurement of ac magnetic susceptibility and flux exclusion or shielding fraction which is also reduced in proportion to increasing peak shock pressure. The high frequency surface resistance (in the GHz range) is also correspondingly compromised in explosively fabricated, bulk metal-matrix composites based on YBa2Cu3O7. Transmission electron microscopy (including lattice imaging techniques) is being applied in an effort to elucidate the fundamental (microstructural) nature of the shock-induced degradation of superconductivity and normal state conductivity. One focus of TEM observations has assumed that oxygen displaced from b-chains rather than oxygen-vacancy disorder in the basal plane of oxygen deficient YBa2Cu3Ox may be a prime mechanism. Shock-wave displaced oxygen may also be locked into new positions or interstitial clusters or chemically bound to displaced metal (possibly copper) atoms to form precipitates, or such displacements may cause the equivalent of local lattice cell changes as a result of stoichiometric changes. While the shock-induced suppression of T(sub c) is not desirable in the explosive fabrication of bulk metal-matrix superconductors, it may be turned into an advantage if the atomic-scale distortion can be understood and controlled as local

  8. Spatially resolved SO2 flux emissions from Mt Etna

    Science.gov (United States)

    Bitetto, M.; Delle Donne, D.; Tamburello, G.; Battaglia, A.; Coltelli, M.; Patanè, D.; Prestifilippo, M.; Sciotto, M.; Aiuppa, A.

    2016-01-01

    Abstract We report on a systematic record of SO2 flux emissions from individual vents of Etna volcano (Sicily), which we obtained using a permanent UV camera network. Observations were carried out in summer 2014, a period encompassing two eruptive episodes of the New South East Crater (NSEC) and a fissure‐fed eruption in the upper Valle del Bove. We demonstrate that our vent‐resolved SO2 flux time series allow capturing shifts in activity from one vent to another and contribute to our understanding of Etna's shallow plumbing system structure. We find that the fissure eruption contributed ~50,000 t of SO2 or ~30% of the SO2 emitted by the volcano during the 5 July to 10 August eruptive interval. Activity from this eruptive vent gradually vanished on 10 August, marking a switch of degassing toward the NSEC. Onset of degassing at the NSEC was a precursory to explosive paroxysmal activity on 11–15 August. PMID:27773952

  9. Comparative data compression techniques and multi-compression results

    International Nuclear Information System (INIS)

    Hasan, M R; Ibrahimy, M I; Motakabber, S M A; Ferdaus, M M; Khan, M N H

    2013-01-01

    Data compression is very necessary in business data processing, because of the cost savings that it offers and the large volume of data manipulated in many business applications. It is a method or system for transmitting a digital image (i.e., an array of pixels) from a digital data source to a digital data receiver. More the size of the data be smaller, it provides better transmission speed and saves time. In this communication, we always want to transmit data efficiently and noise freely. This paper will provide some compression techniques for lossless text type data compression and comparative result of multiple and single compression, that will help to find out better compression output and to develop compression algorithms

  10. 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.

  11. Self-similar compression of a magnetized plasma filled liner

    International Nuclear Information System (INIS)

    Felber, F.S.; Liberman, M.A.; Velikovich, A.L.

    1985-01-01

    New analytic, one-dimensional, self-similar solutions of magnetohydrodynamic equations describing the compression of a magnetized plasma by a thin cylindrical liner are presented. The solutions include several features that have not been included in an earlier self-similar solution of the equations of ideal magnetohydrodynamics. These features are the effects of finite plasma electrical conductivity, induction heating, thermal conductivity and related thermogalvanomagnetic effects, plasma turbulence, and plasma boundary effects. These solutions have been motivated by recent suggestions for production of ultrahigh magnetic fields by new methods. The methods involve radially imploding plasmas in which axial magnetic fields have been entrained. These methods may be capable of producing controlled magnetic fields up to approx. = 100 MG. Specific methods of implosion suggested were by ablative radial acceleration of a liner by a laser and by a gas-puff Z pinch. The model presented here addresses the first of these methods. The solutions derived here are used to estimate magnetic flux losses out of the compression volume, and to indicate conditions under which an impulsively-accelerated, plasma-filled liner may compress an axial magnetic field to large magnitude

  12. 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

  13. 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.

  14. 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...

  15. 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

  16. 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.)

  17. 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.)

  18. Efficient Lossy Compression for Compressive Sensing Acquisition of Images in Compressive Sensing Imaging Systems

    Directory of Open Access Journals (Sweden)

    Xiangwei Li

    2014-12-01

    Full Text Available Compressive Sensing Imaging (CSI is a new framework for image acquisition, which enables the simultaneous acquisition and compression of a scene. Since the characteristics of Compressive Sensing (CS acquisition are very different from traditional image acquisition, the general image compression solution may not work well. In this paper, we propose an efficient lossy compression solution for CS acquisition of images by considering the distinctive features of the CSI. First, we design an adaptive compressive sensing acquisition method for images according to the sampling rate, which could achieve better CS reconstruction quality for the acquired image. Second, we develop a universal quantization for the obtained CS measurements from CS acquisition without knowing any a priori information about the captured image. Finally, we apply these two methods in the CSI system for efficient lossy compression of CS acquisition. Simulation results demonstrate that the proposed solution improves the rate-distortion performance by 0.4~2 dB comparing with current state-of-the-art, while maintaining a low computational complexity.

  19. 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)

  20. 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)

  1. Kinetic Simulations of Plasma Energization and Particle Acceleration in Interacting Magnetic Flux Ropes

    Science.gov (United States)

    Du, S.; Guo, F.; Zank, G. P.; Li, X.; Stanier, A.

    2017-12-01

    The interaction between magnetic flux ropes has been suggested as a process that leads to efficient plasma energization and particle acceleration (e.g., Drake et al. 2013; Zank et al. 2014). However, the underlying plasma dynamics and acceleration mechanisms are subject to examination of numerical simulations. As a first step of this effort, we carry out 2D fully kinetic simulations using the VPIC code to study the plasma energization and particle acceleration during coalescence of two magnetic flux ropes. Our analysis shows that the reconnection electric field and compression effect are important in plasma energization. The results may help understand the energization process associated with magnetic flux ropes frequently observed in the solar wind near the heliospheric current sheet.

  2. 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

  3. 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.

  4. 30 CFR 75.1730 - Compressed air; general; compressed air systems.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Compressed air; general; compressed air systems... Compressed air; general; compressed air systems. (a) All pressure vessels shall be constructed, installed... Safety and Health district office. (b) Compressors and compressed-air receivers shall be equipped with...

  5. Comparison of the Effects of Thermal Pretreatment, Steam Explosion and Ultrasonic Disintegration on Digestibility of Corn Stover

    Directory of Open Access Journals (Sweden)

    Andras Dallos

    2016-06-01

    Full Text Available The energy demand of the corn-based bioethanol production could be reduced using the agricultural byproducts as bioenergy feedstock for biogas digesters. The release of lignocellulosic material and therefore the acceleration of degradation processes can be achieved using thermal and mechanical pretreatments, which assist to hydrolyze the cell walls and speed the solubilization of biopolymers in biogas feedstock. This study is focused on liquid hot water, steam explosion and ultrasonic pretreatments of corn stover. The scientific contribution of this paper is a comprehensive comparison of the performance of the pretreatments by fast analytical, biochemical, anaerobic digestibility and biomethane potential tests, extended by energy consumptions and energy balance calculations.The effectiveness of pretreatments was evaluated by means of soluble chemical oxygen demand, biochemical oxygen demand and by the biogas and methane productivities. The results have shown that the thermal pretreatment, steam explosion and ultrasonic irradiation of biogas feedstock disintegrated the lignocellulosic structure, increased and accelerated the methane production and increased the cumulative biogas and methane productivity of corn stover in reference to the control during mesophilic anaerobic digestion.The energy balance demonstrated that there is an economical basis of the application of the liquid hot-compressed water pretreatments in a biogas plant. However, the steam explosion and ultrasonication are energetically not profitable for corn stover pretreatment.

  6. 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.

  7. 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.)

  8. 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)

  9. On the modelling of compressible inviscid flow problems using AUSM schemes

    Directory of Open Access Journals (Sweden)

    Hajžman M.

    2007-11-01

    Full Text Available During last decades, upwind schemes have become a popular method in the field of computational fluid dynamics. Although they are only first order accurate, AUSM (Advection Upstream Splitting Method schemes proved to be well suited for modelling of compressible flows due to their robustness and ability of capturing shock discontinuities. In this paper, we review the composition of the AUSM flux-vector splitting scheme and its improved version noted AUSM+, proposed by Liou, for the solution of the Euler equations. Mach number splitting functions operating with values from adjacent cells are used to determine numerical convective fluxes and pressure splitting is used for the evaluation of numerical pressure fluxes. Both versions of the AUSM scheme are applied for solving some test problems such as one-dimensional shock tube problem and three dimensional GAMM channel. Features of the schemes are discussed in comparison with some explicit central schemes of the first order accuracy (Lax-Friedrichs and of the second order accuracy (MacCormack.

  10. Gas cloud explosions and their effect on nuclear power plant. Phase 1: basic development of explosion codes

    International Nuclear Information System (INIS)

    Hall, S.F.; Martin, D.; MacKenzie, J.

    1984-01-01

    The study of factors influencing the pressure and velocity fields produced by the burning of clouds of flammable substances has been in progress in SRD for some years. During this time several computer codes have been developed to aid these studies. This report concerns an extension of these studies, which involves firstly, the use of the existing codes for systematic parameter surveys and secondly, the removal of some of the limitations on the code capabilities so that they become capable of producing more realistic representations of real explosions. This work is all aimed at the study of wave and velocity fields and the influence of rigid boundaries, such as the presence of strong buildings, e.g. nuclear power plants. These existing computer models have been used to investigate the scope and range of possible pressure loadings produced by gas cloud explosions and the interaction of their pressure fields with structures. Calculations have been undertaken for a number of different fuels and at different concentrations and burning velocities. The results of some of these calculations have been used in two-dimensional wave-structure interaction calculations with structures representative of nuclear power plant buildings. Finally, the development of a two-dimensional code capable of modelling flame and pressure wave interactions with structures is presented. This code has user-oriented input and output routines with particular attention having been paid to initial conditions, obstacles and graphics. The flux corrected transport method (the state-of-the-art method for dealing with flow with shocks) is used to solve a system of equations consisting of the usual conservation equations and a simple turbulence model (two-equation K-E model) including a simple turbulence-dependent chemical reaction rate

  11. 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)

  12. 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.

  13. 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...

  14. 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).

  15. 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.

  16. 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

  17. Estimates of magnetic flux, and energy balance in the plasma sheet during substorm expansion

    Science.gov (United States)

    Hesse, Michael; Birn, Joachim; Pulkkinen, Tuija

    1996-01-01

    The energy and magnetic flux budgets of the magnetotail plasma sheet during substorm expansion are investigated. The possible mechanisms that change the energy content of the closed field line region which contains all the major dissipation mechanisms of relevance during substorms, are considered. The compression of the plasma sheet mechanism and the diffusion mechanism are considered and excluded. It is concluded that the magnetic reconnection mechanism can accomplish the required transport. Data-based empirical magnetic field models are used to investigate the magnetic flux transport required to account for the observed magnetic field dipolarizations in the inner magnetosphere. It is found that the magnetic flux permeating the current sheet is typically insufficient to supply the required magnetic flux. It is concluded that no major substorm-type magnetospheric reconfiguration is possible in the absence of magnetic reconnection.

  18. 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)

  19. Seismic tremors and magma wagging during explosive volcanism.

    Science.gov (United States)

    Jellinek, A Mark; Bercovici, David

    2011-02-24

    Volcanic tremor is a ubiquitous feature of explosive eruptions. This oscillation persists for minutes to weeks and is characterized by a remarkably narrow band of frequencies from about 0.5 Hz to 7 Hz (refs 1-4). Before major eruptions, tremor can occur in concert with increased gas flux and related ground deformation. Volcanic tremor is thus of particular value for eruption forecasting. Most models for volcanic tremor rely on specific properties of the geometry, structure and constitution of volcanic conduits as well as the gas content of the erupting magma. Because neither the initial structure nor the evolution of the magma-conduit system will be the same from one volcano to the next, it is surprising that tremor characteristics are so consistent among different volcanoes. Indeed, this universality of tremor properties remains a major enigma. Here we employ the contemporary view that silicic magma rises in the conduit as a columnar plug surrounded by a highly vesicular annulus of sheared bubbles. We demonstrate that, for most geologically relevant conditions, the magma column will oscillate or 'wag' against the restoring 'gas-spring' force of the annulus at observed tremor frequencies. In contrast to previous models, the magma-wagging oscillation is relatively insensitive to the conduit structure and geometry, which explains the narrow band of tremor frequencies observed around the world. Moreover, the model predicts that as an eruption proceeds there will be an upward drift in both the maximum frequency and the total signal frequency bandwidth, the nature of which depends on the explosivity of the eruption, as is often observed.

  20. 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.

  1. 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

  2. Electromotive force in strongly compressible magnetohydrodynamic turbulence

    Science.gov (United States)

    Yokoi, N.

    2017-12-01

    Variable density fluid turbulence is ubiquitous in geo-fluids, not to mention in astrophysics. Depending on the source of density variation, variable density fluid turbulence may be divided into two categories: the weak compressible (entropy mode) turbulence for slow flow and the strong compressible (acoustic mode) turbulence for fast flow. In the strong compressible turbulence, the pressure fluctuation induces a strong density fluctuation ρ ', which is represented by the density variance ( denotes the ensemble average). The turbulent effect on the large-scale magnetic-field B induction is represented by the turbulent electromotive force (EMF) (u': velocity fluctuation, b': magnetic-field fluctuation). In the usual treatment in the dynamo theory, the expression for the EMF has been obtained in the framework of incompressible or weak compressible turbulence, where only the variation of the mean density , if any, is taken into account. We see from the equation of the density fluctuation ρ', the density variance is generated by the large mean density variation ∂ coupled with the turbulent mass flux . This means that in the region where the mean density steeply changes, the density variance effect becomes relevant for the magnetic field evolution. This situation is typically the case for phenomena associated with shocks and compositional discontinuities. With the aid of the analytical theory of inhomogeneous compressible magnetohydrodynamic (MHD) turbulence, the expression for the turbulent electromotive force is investigated. It is shown that, among others, an obliqueness (misalignment) between the mean density gradient ∂ and the mean magnetic field B may contribute to the EMF as ≈χ B×∂ with the turbulent transport coefficient χ proportional to the density variance (χ ). This density variance effect is expected to strongly affect the EMF near the interface, and changes the transport properties of turbulence. In the case of an interface under the MHD slow

  3. Buckets of ash track tephra flux from Halema'uma'u Crater, Hawai'i

    Science.gov (United States)

    Swanson, Don; Wooten, Kelly M.; Orr, Tim R.

    2009-01-01

    The 2008–2009 eruption at Kīlauea Volcano's summit made news because of its eight small discrete explosive eruptions and noxious volcanic smog (vog) created from outgassing sulfur dioxide. Less appreciated is the ongoing, weak, but continuous output of tephra, primarily ash, from the new open vent in Halema'uma'u Crater. This tephra holds clues to processes causing the eruption and forming the new crater-in-a-crater, and its flux is important to hazard evaluations.The setting of the vent–easily accessible from the Hawaiian Volcano Observatory (HVO)—is unusually favorable for neardaily tracking of tephra mass flux during this small prolonged basaltic eruption. Recognizing this, scientists from HVO are collecting ash and documenting how ejection masses, components, and chemical compositions vary through time.

  4. SeqCompress: an algorithm for biological sequence compression.

    Science.gov (United States)

    Sardaraz, Muhammad; Tahir, Muhammad; Ikram, Ataul Aziz; Bajwa, Hassan

    2014-10-01

    The growth of Next Generation Sequencing technologies presents significant research challenges, specifically to design bioinformatics tools that handle massive amount of data efficiently. Biological sequence data storage cost has become a noticeable proportion of total cost in the generation and analysis. Particularly increase in DNA sequencing rate is significantly outstripping the rate of increase in disk storage capacity, which may go beyond the limit of storage capacity. It is essential to develop algorithms that handle large data sets via better memory management. This article presents a DNA sequence compression algorithm SeqCompress that copes with the space complexity of biological sequences. The algorithm is based on lossless data compression and uses statistical model as well as arithmetic coding to compress DNA sequences. The proposed algorithm is compared with recent specialized compression tools for biological sequences. Experimental results show that proposed algorithm has better compression gain as compared to other existing algorithms. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. 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.

  6. 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.

  7. 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)

  8. 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)

  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. 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...

  11. KoFlux: Korean Regional Flux Network in AsiaFlux

    Science.gov (United States)

    Kim, J.

    2002-12-01

    AsiaFlux, the Asian arm of FLUXNET, held the Second International Workshop on Advanced Flux Network and Flux Evaluation in Jeju Island, Korea on 9-11 January 2002. In order to facilitate comprehensive Asia-wide studies of ecosystem fluxes, the meeting launched KoFlux, a new Korean regional network of long-term micrometeorological flux sites. For a successful assessment of carbon exchange between terrestrial ecosystems and the atmosphere, an accurate measurement of surface fluxes of energy and water is one of the prerequisites. During the 7th Global Energy and Water Cycle Experiment (GEWEX) Asian Monsoon Experiment (GAME) held in Nagoya, Japan on 1-2 October 2001, the Implementation Committee of the Coordinated Enhanced Observing Period (CEOP) was established. One of the immediate tasks of CEOP was and is to identify the reference sites to monitor energy and water fluxes over the Asian continent. Subsequently, to advance the regional and global network of these reference sites in the context of both FLUXNET and CEOP, the Korean flux community has re-organized the available resources to establish a new regional network, KoFlux. We have built up domestic network sites (equipped with wind profiler and radiosonde measurements) over deciduous and coniferous forests, urban and rural rice paddies and coastal farmland. As an outreach through collaborations with research groups in Japan, China and Thailand, we also proposed international flux sites at ecologically and climatologically important locations such as a prairie on the Tibetan plateau, tropical forest with mixed and rapid land use change in northern Thailand. Several sites in KoFlux already begun to accumulate interesting data and some highlights are presented at the meeting. The sciences generated by flux networks in other continents have proven the worthiness of a global array of micrometeorological flux towers. It is our intent that the launch of KoFlux would encourage other scientists to initiate and

  12. 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

  13. Explosive-driven hemispherical implosions for generating fusion plasmas

    International Nuclear Information System (INIS)

    Sagie, D.; Glass, I.I.

    1982-03-01

    The UTIAS explosive-driven-implosion facility was used to produce stable, centered and focussed hemispherical implosions to generate neutrons from D-D reactions. A high resolution scintillator-detection system measured the neutrons and γ-rays resulting from the fusion of deuterium. Several approaches were used to initiate fusion in deuterium. The simplest and most direct proved to be in a predetonated stoichiometric mixture of deuterium-oxygen. The other successful method was a miniature Voitenko-type compressor where a plane diaphragm was driven by the implosion wave into a secondary small spherical cavity that contained pure deuterium gas at one atmosphere. A great deal of work still remains in order to measure accurately the neutron flux and its velocity distribution as well as the precise interactions of the neturons with the steel chamber which produced the γ-rays. Nevertheless, this is the only known work where fusion neutrons were produced by chemical energy only in a direct and indirect manner

  14. Intrinsic Compressive Stress in Polycrystalline Films is Localized at Edges of the Grain Boundaries

    Science.gov (United States)

    Vasco, Enrique; Polop, Celia

    2017-12-01

    The intrinsic compression that arises in polycrystalline thin films under high atomic mobility conditions has been attributed to the insertion or trapping of adatoms inside grain boundaries. This compression is a consequence of the stress field resulting from imperfections in the solid and causes the thermomechanical fatigue that is estimated to be responsible for 90% of mechanical failures in current devices. We directly measure the local distribution of residual intrinsic stress in polycrystalline thin films on nanometer scales, using a pioneering method based on atomic force microscopy. Our results demonstrate that, at odds with expectations, compression is not generated inside grain boundaries but at the edges of gaps where the boundaries intercept the surface. We describe a model wherein this compressive stress is caused by Mullins-type surface diffusion towards the boundaries, generating a kinetic surface profile different from the mechanical equilibrium profile by the Laplace-Young equation. Where the curvatures of both profiles differ, an intrinsic stress is generated in the form of Laplace pressure. The Srolovitz-type surface diffusion that results from the stress counters the Mullins-type diffusion and stabilizes the kinetic surface profile, giving rise to a steady compression regime. The proposed mechanism of competition between surface diffusions would explain the flux and time dependency of compressive stress in polycrystalline thin films.

  15. 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)

  16. 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

  17. 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)

  18. 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.

  19. 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

  20. 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.

  1. Modelling of nuclear explosions in hard rock sites

    International Nuclear Information System (INIS)

    Brunish, W.M.; App, F.N.

    1993-01-01

    This study represents part of a larger effort to systematically model the effects of differing source region properties on ground motion from underground nuclear explosions at the Nevada Test Site. In previous work by the authors the primary emphasis was on alluvium and both saturated and unsaturated tuff. We have attempted to model events on Pahute Mesa, where either the working point medium, or some of the layers above the working point, or both, are hard rock. The complex layering at these sites, however, has prevented us from drawing unambiguous conclusions about modelling hard rock. In order to learn more about the response of hard rock to underground nuclear explosions, we have attempted to model the PILEDRIVER event. PILEDRIVER was fired on June 2, 1966 in the granite stock of Area 15 at the Nevada Test Site. The working point was at a depth of 462.7 m and the yield was determined to be 61 kt. Numerous surface, sub-surface and free-field measurements were made and analyzed by SRI. An attempt was made to determine the contribution of spall to the teleseismic signal, but proved unsuccessful because most of the data from below-shot-level gauges was lost. Nonetheless, there is quite a bit of good quality data from a variety of locations. We have been able to obtain relatively good agreement with the experimental PILEDRIVER waveforms. In order to do so, we had to model the granodiorite as being considerably weaker than ''good quality'' granite, and it had to undergo considerable weakening due to shock damage as well. In addition, the near-surface layers had to be modeled as being weak and compressible and as have a much lower sound speed than the material at depth. The is consistent with a fractured and jointed material at depth, and a weathered material near the surface

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. Prediction of Ignition of High Explosive When Submitted To Impact

    Science.gov (United States)

    Picart, Didier; Delmaire-Sizes, Franck; Gruau, Cyril; Trumel, Herve

    2009-06-01

    High explosive structures may unintentionally ignite and transit to deflagration or detonation, when subjected to mechanical loadings, such as low velocity impact. We focus our attention on ignition. The Browning and Scammon [1] criterion has been adapted. A concrete like constitutive law is derived, with an up-to-date experimental characterization. These models have been implemented in Abaqus/Explicit [2]. Numerical simulations are used to calibrate the ignition threshold. The presentation or the poster will detail the main assumptions, the models (Browning et al, mechanical behavior) and the calibration procedure. Comparisons between numerical results and experiments [3] will show the interest of this method but also its limitations (numerical artifacts, lack of mechanical data, misinterpretation of reactive tests). [1] R. Browning and R. Scammon, Shock compression of condensed matter, pp. 987-990, (2001). [2] C. Gruau, D. Picart et al., 17^th Dymat technical meeting, Cambridge, UK, (2007). [3] F. Delmaire-Sizes et al., 3^rd International symposium on energetic materials, Tokyo, Japan, (2008).

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. Radiological Image Compression

    Science.gov (United States)

    Lo, Shih-Chung Benedict

    The movement toward digital images in radiology presents the problem of how to conveniently and economically store, retrieve, and transmit the volume of digital images. Basic research into image data compression is necessary in order to move from a film-based department to an efficient digital -based department. Digital data compression technology consists of two types of compression technique: error-free and irreversible. Error -free image compression is desired; however, present techniques can only achieve compression ratio of from 1.5:1 to 3:1, depending upon the image characteristics. Irreversible image compression can achieve a much higher compression ratio; however, the image reconstructed from the compressed data shows some difference from the original image. This dissertation studies both error-free and irreversible image compression techniques. In particular, some modified error-free techniques have been tested and the recommended strategies for various radiological images are discussed. A full-frame bit-allocation irreversible compression technique has been derived. A total of 76 images which include CT head and body, and radiographs digitized to 2048 x 2048, 1024 x 1024, and 512 x 512 have been used to test this algorithm. The normalized mean -square-error (NMSE) on the difference image, defined as the difference between the original and the reconstructed image from a given compression ratio, is used as a global measurement on the quality of the reconstructed image. The NMSE's of total of 380 reconstructed and 380 difference images are measured and the results tabulated. Three complex compression methods are also suggested to compress images with special characteristics. Finally, various parameters which would effect the quality of the reconstructed images are discussed. A proposed hardware compression module is given in the last chapter.

  13. Computation of steady and unsteady compressible quasi-axisymmetric vortex flow and breakdown

    Science.gov (United States)

    Kandil, Osama A.; Kandil, Hamdy A.; Liu, C. H.

    1991-01-01

    The unsteady, compressible Navier-Stokes equations are used to compute and analyze compressible quasi-axisymmetric isolated vortices. The Navier-Stokes equations are solved using an implicit, upwind, flux-difference splitting finite-volume scheme. The developed three-dimensional solver has been verified by comparing its solution profiles with those of a slender, quasi-axisymmetric vortex solver for a subsonic, isolated quasi-axisymmetric vortex in an unbounded domain. The Navier-Stokes solver is then used to solve for a supersonic quasi-axisymmetric vortex flow in a configured circular duct. Steady and unsteady vortex-shock interactions and breakdown have been captured. The problem has also been calculated using the Euler solver of the same code and the results are compared with those of the Navier-Stokes solver. The effect of the initial swirl has been tentatively studied.

  14. Time-resolved dynamics of nanosecond laser-induced phase explosion

    International Nuclear Information System (INIS)

    Porneala, Cristian; Willis, David A

    2009-01-01

    Visualization of Nd : YAG laser ablation of aluminium targets was performed by a shadowgraph apparatus capable of imaging the dynamics of ablation with nanosecond time resolution. Direct observations of vaporization, explosive phase change and shock waves were obtained. The influence of vaporization and phase explosion on shock wave velocity was directly measured. A significant increase in the shock wave velocity was observed at the onset of phase explosion. However, the shock wave behaviour followed the form of a Taylor-Sedov spherical shock below and above the explosive phase change threshold. The jump in the shock wave velocity above phase explosion threshold is attributed to the release of stored enthalpy in the superheated liquid surface. The energy released during phase explosion was estimated by fitting the transient shock wave position to the Taylor scaling rules. Results of temperature calculations indicate that the vapour temperature at the phase explosion threshold is slightly higher than the critical temperature at the early stages of the shock wave formation. The shock wave pressure nearly doubled when transitioning from normal vaporization to phase explosion.

  15. Filling bore-holes with explosive

    Energy Technology Data Exchange (ETDEWEB)

    Alfredsson, S H

    1965-03-02

    In this device for filling boreholes formed in a rock formation with particulate explosive, the explosive is conveyed into the hole by means of a pressure fluid through a tube which has a lesser diameter than the hole. The tube is characterized by a lattice work arranged externally on it, and having a structure adapted to allow passage of a pressure fluid returning between the tube and the wall of the hole, but retaining particles of explosive entrained by the returning pressure fluid. In another arrangement of the device, the lattice work has the form of a brush, including filaments or bristles which are dimensioned to bridge the spacing between the tube and the wall of the hole. (12 claims)

  16. Calculating overpressure from BLEVE explosions

    Energy Technology Data Exchange (ETDEWEB)

    Planas-Cuchi, E.; Casal, J. [Universitat Politecnica de Catalunya, Barcelona (Spain). Department of Chemical Engineering, Centre for Technological Risk Studies; Salla, J.M. [Universitat Politecnica de Catalunya, Barcelona (Spain). Department of Heat Engines

    2004-11-01

    Although a certain number of authors have analyzed the prediction of boiling liquid expanding vapour explosion (BLEVE) and fireball effects, only very few of them have proposed methodologies for predicting the overpressure from such explosions. In this paper, the methods previously published are discussed and shown to introduce a significant overestimation due to erroneous thermodynamic assumptions - ideal gas behaviour and isentropic vapour expansion - on which they are based (in fact, they give the maximum value of overpressure which can be caused by a BLEVE). A new approach is proposed, based on the - more realistic - assumption of an adiabatic and irreversible expansion process; the real properties of the substance involved in the explosion are used. The two methods are compared through the application to a given case. (author)

  17. Evidence for nearby supernova explosions

    International Nuclear Information System (INIS)

    Benitez, Narciso; Maiz-Apellaniz, Jesus; Canelles, Matilde

    2002-01-01

    Supernova (SN) explosions are one of the most energetic--and potentially lethal--phenomena in the Universe. We show that the Scorpius-Centaurus OB association, a group of young stars currently located at ∼130 pc from the Sun, has generated 20 SN explosions during the last 11 Myr, some of them probably as close as 40 pc to our planet. The deposition on Earth of 60 Fe atoms produced by these explosions can explain the recent measurements of an excess of this isotope in deep ocean crust samples. We propose that ∼2 Myr ago, one of the SNe exploded close enough to Earth to seriously damage the ozone layer, provoking or contributing to the Pliocene-Pleistocene boundary marine extinction

  18. Rotor Systems Research Aircraft /RSRA/ canopy explosive severance/fracture

    Science.gov (United States)

    Bement, L. J.

    1976-01-01

    The Rotor Systems Research Aircraft (RSRA), a compound rotor/fixed-wing aircraft, incorporates an emergency escape system for the three crew members; to achieve unobstructed egress, the overhead acrylic canopies of each crew member will be explosively severed and fractured into predictably small, low-mass pieces. A canopy explosive severance/fracture system was developed under this investigation that included the following system design considerations: selection of canopy and explosive materials, determining the acrylic's explosive severance and fracture characteristics, evaluating the effects of installation variables and temperature, determining the most effective explosive patterns, conducting full-scale, flat and double-curvature canopy tests, and evaluating the effects of back-blast of the explosive into the cockpit.

  19. Explosives remain preferred methods for platform abandonment

    International Nuclear Information System (INIS)

    Pulsipher, A.; Daniel, W. IV; Kiesler, J.E.; Mackey, V. III

    1996-01-01

    Economics and safety concerns indicate that methods involving explosives remain the most practical and cost-effective means for abandoning oil and gas structures in the Gulf of Mexico. A decade has passed since 51 dead sea turtles, many endangered Kemp's Ridleys, washed ashore on the Texas coast shortly after explosives helped remove several offshore platforms. Although no relationship between the explosions and the dead turtles was ever established, in response to widespread public concern, the US Minerals Management Service (MMS) and National Marine Fisheries Service (NMFS) implemented regulations limiting the size and timing of explosive charges. Also, more importantly, they required that operators pay for observers to survey waters surrounding platforms scheduled for removal for 48 hr before any detonations. If observers spot sea turtles or marine mammals within the danger zone, the platform abandonment is delayed until the turtles leave or are removed. However, concern about the effects of explosives on marine life remains

  20. 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

  1. Off-center point explosion in a spheroid

    International Nuclear Information System (INIS)

    Morita, Kazuhiko; Sakashita, Shiro

    1978-01-01

    An off-center point explosion in a spheroid with exponential or Gaussian density distribution is investigated by applying the generalized Laumbach and Probstein method. For a typical example, we calculate the explosion in a spheroid with the eccentricity e = 0.7. If the separation distance between the center of the spheroid and the explosion point is larger than three times of the density scale height, the shock wave may almost propagate toward the direction of the minor axis of symmetry, within the polar angle of 30 0 . The shock envelope elongates toward the same direction and may form a polar jet and/or a tilted jet. But, in the case of an explosion in the equatorial plane (perpendicular to the minor axis of symmetry), two plasmas with the same form may be ejected into two different directions with the angle smaller than 180 0 . Explosion models of double radio sources and related objects are suggested. (author)

  2. Application of factor analysis to the explosive detection

    International Nuclear Information System (INIS)

    Park, Yong Joon; Song, Byung Chul; Im, Hee Jung; Kim, Won Ho; Cho, Jung Hwan

    2005-01-01

    The detection of explosive devices hidden in airline baggage is significant problem, particularly in view of the development of modern plastic explosives which can formed into various innocent-appearing shapes and which are sufficiently powerful that small quantities can destroy an aircraft in flight. Besides, the biggest difficulty occurs from long detection time required for the explosive detection system based on thermal neutron interrogation, which involves exposing baggage to slow neutrons having energy in the order of 0.025 eV. The elemental compositions of explosives can be determined by the Neutron Induced Prompt gamma Spectroscopy (NIPS) which has been installed in Korea Atomic Energy Research Institute as a tool for the detection of explosives in passenger baggage. In this work, the factor analysis has been applied to the NIPS system to increase the signal-to-noise ratio of the prompt gamma spectrum for the detection of explosive hidden in a passenger's baggage, especially for the noisy prompt gamma spectrum obtained with short measurement time

  3. Explosions and light curves of supernovae

    International Nuclear Information System (INIS)

    Gaffet, B.

    1975-01-01

    The models developed to explain supernovae explosions are reviewed. The first one is thermonuclear explosion (simple or preceded by an implosion phase); the neutrino emission which results of such an explosion can have an important dynamical effect, according as the star is opaque or transparent to them; another theory involves the radiation pressure of the pulsar which is formed in the center of the star. The origin of the supernovae brightness is also uncertain: the initial heat due to the explosion does not seem to be sufficient; the brightness can result from the diffusion of the heat through the ejected matter or can be transported more rapidly by a shock wave. A model in which the heat is produced by the pulsar seems compatible with most observations (shapes of the brightness curves and the continuum spectra, expansion velocities, temperature and luminosity at the peak, total kinetic energy) [fr

  4. One-Dimensional Time to Explosion (Thermal Sensitivity) of ANPZ

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hust, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); McClelland, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gresshoff, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-11-12

    Incidents caused by fire and combat operations can heat energetic materials that may lead to thermal explosion and result in structural damage and casualty. Some explosives may thermally explode at fairly low temperatures (< 100 C) and the violence from thermal explosion may cause a significant damage. Thus it is important to understand the response of energetic materials to thermal insults. The One Dimensional Time to Explosion (ODTX) system at the Lawrence Livermore National Laboratory has been used for decades to measure times to explosion, threshold thermal explosion temperature, and determine kinetic parameters of energetic materials. Samples of different configurations (pressed part, powder, paste, and liquid) can be tested in the system. The ODTX testing can also provide useful data for assessing the thermal explosion violence of energetic materials. This report summarizes the recent ODTX experimental data and modeling results for 2,6-diamino-3,5-dintropyrazine (ANPZ).

  5. An examination of Southwest Pacific explosive cyclones, 1989 to 2009

    International Nuclear Information System (INIS)

    Black, M T; Pezza, A B; Kreft, P

    2010-01-01

    This study has assembled a climatology of Southwest Pacific explosively developing cyclones, based on the European Centre for Medium-Range Weather Forecasts' ERA-Interim reanalysis data, over the 21-year period from 1989 to 2009. The recently developed 'combined explosive' expression, a refinement of the 'relative explosive' criterion, was used to identify cyclones deemed explosive with respect to both the drop in central pressure and the climatological pressure gradient. Over the period of analysis, 47 explosive cyclones were identified within the Southwest Pacific, equating to an average of 2.2 explosive events per year. Seasonally, explosive cyclones are most frequent during the winter months, while least frequent during the summer. Two case explosive systems are briefly considered, with their corresponding measures of intensity and scale placed into climatological perspective.

  6. Vapor explosion studies for nuclear and non-nuclear industries

    Energy Technology Data Exchange (ETDEWEB)

    Taleyarkhan, Rusi P. [Arden L. Bement, Jr. Professor Nuclear Engineering, School of Nuclear Engineering, 1290 Nuclear Engineering Building, Room 108C, Purdue University, West Lafayette, IN 47905 (United States)]. E-mail: rusi@purdue.edu

    2005-05-01

    Energetic melt-water explosions are a well-established contributor to risk for nuclear reactors, and even more so for the metal casting industry. In-depth studies were undertaken in an industry-national laboratory collaborative effort to understand the root causes of explosion triggering and to evaluate methods for prevention. The steam explosion triggering studies (SETS) facility was devised and implemented for deriving key insights into explosion prevention. Data obtained indicated that onset of base surface-entrapment induced explosive boiling-caused trigger shocks is a result of complex combination of surface wettability, type of coating (organic versus inorganic), degree of coating wearoff, existence of bypass pathways for pressure relief, charring and non-condensable gas (NCG) release potential. Of these parameters NCGs were found to play a preeminent role on explosion prevention by stabilizing the melt-water steam interface and acting as a shock absorber. The role of NCGs was experimentally confirmed using SETS for their effect on stable film boiling using a downward facing heated body through which gases were injected. The presence of NCGs in the steam film layer caused a significant delay in the transitioning of film-to-nucleate boiling. The role of NCGs on explosion prevention was thereafter demonstrated more directly by introducing molten metal drops into water pools with and without NCG bubbling. Whereas spontaneous and energetic explosions took place without NCG injection, only benign quenching occurred in the presence of NCGs. Gravimetric analyses of organic coatings which are known to prevent explosion onset were also found to release significant NCGs during thermal attack by melt in the presence of water. These findings offer a novel, simple, cost-effective technique for deriving fundamental insights into melt-water explosions as well as for explosion prevention under most conditions of interest to metal casting, and possibly for nuclear reactor

  7. 30 CFR 75.1311 - Transporting explosives and detonators.

    Science.gov (United States)

    2010-07-01

    ... noncombustible materials. (c) When explosives and detonators are transported on conveyor belts— (1) Containers of... explosives or detonators, a person shall be at each transfer point between belts and at the unloading location; and (4) Conveyor belts shall be stopped before explosives or detonators are loaded or unloaded...

  8. 29 CFR 1926.902 - Surface transportation of explosives.

    Science.gov (United States)

    2010-07-01

    ... electric) shall not be transported in the same vehicle with other explosives. (e) Vehicles used for... prevent contact with containers of explosives. (h) Every motor vehicle or conveyance used for transporting... Carriers. (b) Motor vehicles or conveyances transporting explosives shall only be driven by, and be in the...

  9. 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.

  10. Do peaceful nuclear explosions have a future

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    The idea of peaceful uses for nuclear explosive devices arose almost simultaneously with the concept of the nuclear explosion itself. It has been a powerful idea in that it soon generated major study efforts in the United States and the USSR and also captured the interest of many developing nations. But in spite of this considerable interest and much expenditure of funds and effort, the expectation that economically viable uses will be found for peaceful nuclear explosions looks even more distant now that when the first studies were initiated. This, at least, is the conclusion of two recent U.S. studies of the economic feasibility and time scale for application of peaceful nuclear explosions by the United States. The larger of these two studies was prepared by the Gulf Universities Research Consortium, and dealt particularly with possibilities for use in the United States by 1990 of contained, i.e., underground, peaceful nuclear explosions. This paper provides briefer analysis by an ad hoc panel assesses the implications of the Gulf report, considers other uses for peaceful nuclear explosions, and summarizes the reasons why there is only a small possibility that there will be significant use of them by the United States before the year 2000

  11. Vapor generation methods for explosives detection research

    Energy Technology Data Exchange (ETDEWEB)

    Grate, Jay W.; Ewing, Robert G.; Atkinson, David A.

    2012-12-01

    The generation of calibrated vapor samples of explosives compounds remains a challenge due to the low vapor pressures of the explosives, adsorption of explosives on container and tubing walls, and the requirement to manage (typically) multiple temperature zones as the vapor is generated, diluted, and delivered. Methods that have been described to generate vapors can be classified as continuous or pulsed flow vapor generators. Vapor sources for continuous flow generators are typically explosives compounds supported on a solid support, or compounds contained in a permeation or diffusion device. Sources are held at elevated isothermal temperatures. Similar sources can be used for pulsed vapor generators; however, pulsed systems may also use injection of solutions onto heated surfaces with generation of both solvent and explosives vapors, transient peaks from a gas chromatograph, or vapors generated by s programmed thermal desorption. This article reviews vapor generator approaches with emphasis on the method of generating the vapors and on practical aspects of vapor dilution and handling. In addition, a gas chromatographic system with two ovens that is configurable with up to four heating ropes is proposed that could serve as a single integrated platform for explosives vapor generation and device testing. Issues related to standards, calibration, and safety are also discussed.

  12. Explosive Technology Group

    Data.gov (United States)

    Federal Laboratory Consortium — The Explosive Technology Group (ETG) provides diverse technical expertise and an agile, integrated approach to solve complex challenges for all classes of energetic...

  13. Decreasing Friction Sensitivity for Primary Explosives

    Science.gov (United States)

    Matyáš, Robert; Šelešovský, Jakub

    2014-04-01

    Primary explosives are a group of explosives that are widely used in various initiating devices. One of their properties is sufficient sensitivity to initiating stimuli. However, their sensitivity often introduces a safety risk during their production and subsequent handling. It is generally known that water can be used to desensitize these compounds. The most commonly used industrial primary explosives (lead azide, lead styphnate, tetrazene, and diazodinitrophenol) were mixed with water in various ratios and the sensitivity to friction was determined for all mixtures. It was found that even a small addition of water (5-10%) considerably lowered the friction sensitivity.

  14. Method for enhancing stability of high explosives, for purposes of transport or storage, and the stabilized high explosives

    International Nuclear Information System (INIS)

    Nutt, G.L.

    1991-01-01

    This papent describes a method for suppressing the tendency of a porous solid high explosive to ignite and detonate. It comprises: filling substantially all the press of the solid high explosive material with a predetermined pore radius of at least 10μm with a relatively inert, stable, pore filling material in liquid form, the pore filling being selected from gallium, rubidium-potassium eutectic, and Wood's metal; and solidifying the pore filling material in the pores of the explosive material

  15. Contained fission explosion breeder reactor system

    International Nuclear Information System (INIS)

    Juhl, N.H.; Marwick, E.F.

    1983-01-01

    A reactor system for producing useful thermal energy and valuable isotopes, such as plutonium-239, uranium-233, and/or tritium, in which a pair of sub-critical masses of fissile and fertile actinide slugs are propelled into an ellipsoidal pressure vessel. The propelled slugs intercept near the center of the chamber where the concurring slugs become a more than prompt configuration thereby producing a fission explosion. Re-useable accelerating mechanisms are provided external of the vessel for propelling the slugs at predetermined time intervals into the vessel. A working fluid of lean molten metal slurry is injected into the chamber prior to each explosion for the attenuation of the explosion's effects, for the protection of the chamber's walls, and for the absorbtion of thermal energy and debris from the explosion. The working fluid is injected into the chamber in a pattern so as not to interfere with the flight paths of the slugs and to maximize the concentration of working fluid near the chamber's center. The heated working fluid is drained from the vessel and is used to perform useful work. Most of the debris from the explosion is collected as precipitate and is used for the manufacture of new slugs

  16. Bulk-loaded emulsion explosives technology

    Energy Technology Data Exchange (ETDEWEB)

    Borg, D.G. [Blasting Analysis International, Inc., Allentown, PA (United States)

    1995-01-01

    The largest use of emulsion explosives and emulsion-Anfo blends is in surface mining operations. An emulsion explosive is a two-phase system: the inner phase is madeup of an oxidizer solution; the outer phase is made up of oils or an oil/wax blend. Emulsion Anfo blends have been used to expand drill patterns, increase fragmentation, and provide extra energy for blast casting. 3 tabs.

  17. Regional moment: Magnitude relations for earthquakes and explosions

    Energy Technology Data Exchange (ETDEWEB)

    Patton, H.J.; Walter, W.R. (Lawrence Livermore National Lab., CA (United States))

    1993-02-19

    The authors present M[sub o]:m[sub b] relations using m[sub b](P[sub n]) and m[sub b](L[sub g]) for earthquakes and explosions occurring in tectonic and stable areas. The observations for m[sub b](P[sub n]) range from about 3 to 6 and show excellent separation between earthquakes and explosions on M[sub o]:m[sub b] plots, independent of the magnitude. The scatter in M[sub o]:M[sub b] observations for NTS explosions is small compared to the earthquake data. The M[sub o]:m[sub b](L[sub g]) data for Soviet explosions overlay the observations for US explosions. These results, and the small scatter for NTS explosions, suggest weak dependence of M[sub o]:m[sub b] relations on emplacement media. A simple theoretical model is developed which matches all these observations. The model uses scaling similarity and conservation of energy to provide a physical link between seismic moment and a broadband seismic magnitude. Three factors, radiation pattern, material property, and apparent stress, contribute to the separation between earthquakes and explosions. This theoretical separation is independent of broadband magnitude. For US explosions in different media, the material property and apparent stress contributions are shown to compensate for one another, supporting the observations that M[sub o]:M[sub b] is nearly independent of source geology. 19 refs., 2 figs., 1 tab.

  18. WSNs Microseismic Signal Subsection Compression Algorithm Based on Compressed Sensing

    Directory of Open Access Journals (Sweden)

    Zhouzhou Liu

    2015-01-01

    Full Text Available For wireless network microseismic monitoring and the problems of low compression ratio and high energy consumption of communication, this paper proposes a segmentation compression algorithm according to the characteristics of the microseismic signals and the compression perception theory (CS used in the transmission process. The algorithm will be collected as a number of nonzero elements of data segmented basis, by reducing the number of combinations of nonzero elements within the segment to improve the accuracy of signal reconstruction, while taking advantage of the characteristics of compressive sensing theory to achieve a high compression ratio of the signal. Experimental results show that, in the quantum chaos immune clone refactoring (Q-CSDR algorithm for reconstruction algorithm, under the condition of signal sparse degree higher than 40, to be more than 0.4 of the compression ratio to compress the signal, the mean square error is less than 0.01, prolonging the network life by 2 times.

  19. Explosion-proof lighting units according to EC standards

    Energy Technology Data Exchange (ETDEWEB)

    Olenik, H; Weyer, K

    1982-03-01

    Electrical equipment, e.g. lights, may be the cause of ignition in explosive atmospheres unless special measures are taken to prevent ignition. For an exact definition and description of explosion protection measures, the German VDE regulations contain specifications for construction and testing. There is a special administrative procedure to ensure that these explosion protection measures are checked by an official testing authority and that electrical equipment will receive a certificate of its suitability for explosive environments. The construction specifications have been elaborated by a VDE commission and are constantly updated.

  20. Dimensional analysis of small-scale steam explosion experiments

    International Nuclear Information System (INIS)

    Huh, K.; Corradini, M.L.

    1986-01-01

    Dimensional analysis applied to Nelson's small-scale steam explosion experiments to determine the qualitative effect of each relevant parameter for triggering a steam explosion. According to experimental results, the liquid entrapment model seems to be a consistent explanation for the steam explosion triggering mechanism. The three-dimensional oscillatory wave motion of the vapor/liquid interface is analyzed to determine the necessary conditions for local condensation and production of a coolant microjet to be entrapped in fuel. It is proposed that different contact modes between fuel and coolant may involve different initiation mechanisms of steam explosions

  1. 77 FR 55108 - Explosive Siting Requirements

    Science.gov (United States)

    2012-09-07

    ... energy, or a chemical explosion requiring a chemical reaction. Furthermore, an accident may happen... for energetic liquids. \\4\\ Crowl, D.A., Understanding Explosions, AIAA Center for Chemical Process... chemical hazards of energetic liquids used at commercial launch sites. Finally, a site map must now be at a...

  2. Self-adjusting entropy-stable scheme for compressible Euler equations

    Institute of Scientific and Technical Information of China (English)

    程晓晗; 聂玉峰; 封建湖; LuoXiao-Yu; 蔡力

    2015-01-01

    In this work, a self-adjusting entropy-stable scheme is proposed for solving compressible Euler equations. The entropy-stable scheme is constructed by combining the entropy conservative flux with a suitable diffusion operator. The entropy has to be preserved in smooth solutions and be dissipated at shocks. To achieve this, a switch function, based on entropy variables, is employed to make the numerical diffusion term added around discontinuities automatically. The resulting scheme is still entropy-stable. A number of numerical experiments illustrating the robustness and accuracy of the scheme are presented. From these numerical results, we observe a remarkable gain in accuracy.

  3. A blended pressure/density based method for the computation of incompressible and compressible flows

    International Nuclear Information System (INIS)

    Rossow, C.-C.

    2003-01-01

    An alternative method to low speed preconditioning for the computation of nearly incompressible flows with compressible methods is developed. For this approach the leading terms of the flux difference splitting (FDS) approximate Riemann solver are analyzed in the incompressible limit. In combination with the requirement of the velocity field to be divergence-free, an elliptic equation to solve for a pressure correction to enforce the divergence-free velocity field on the discrete level is derived. The pressure correction equation established is shown to be equivalent to classical methods for incompressible flows. In order to allow the computation of flows at all speeds, a blending technique for the transition from the incompressible, pressure based formulation to the compressible, density based formulation is established. It is found necessary to use preconditioning with this blending technique to account for a remaining 'compressible' contribution in the incompressible limit, and a suitable matrix directly applicable to conservative residuals is derived. Thus, a coherent framework is established to cover the discretization of both incompressible and compressible flows. Compared with standard preconditioning techniques, the blended pressure/density based approach showed improved robustness for high lift flows close to separation

  4. Multi-scale fracture damage associated with underground chemical explosions

    Science.gov (United States)

    Swanson, E. M.; Sussman, A. J.; Wilson, J. E.; Townsend, M. J.; Prothro, L. B.; Gang, H. E.

    2018-05-01

    Understanding rock damage induced by explosions is critical for a number of applications including the monitoring and verification of underground nuclear explosions, mine safety issues, and modeling fluid flow through fractured rock. We use core observations, televiewer logs, and thin section observations to investigate fracture damage associated with two successive underground chemical explosions (SPE2 and SPE3) in granitic rock at both the mesoscale and microscale. We compare the frequency and orientations of core-scale fractures, and the frequency of microfractures, between a pre-experiment core and three post-experiment cores. Natural fault zones and explosion-induced fractures in the vicinity of the explosive source are readily apparent in recovered core and in thin sections. Damage from faults and explosions is not always apparent in fracture frequency plots from televiewer logs, although orientation data from these logs suggests explosion-induced fracturing may not align with the pre-existing fracture sets. Core-scale observations indicate the extent of explosion-induced damage is 10.0 m after SPE2 and 6.8 m after SPE3, despite both a similar size and location for both explosions. At the microscale, damage is observed to a range distance of 10.2 ± 0.9 m after SPE2, and 16.6 ± 0.9 and 11.2 ± 0.6 in two different cores collected after SPE3. Additional explosion-induced damage, interpreted to be the result of spalling, is readily apparent near the surface, but only in the microfracture data. This depth extent and intensity of damage in the near-surface region also increased after an additional explosion. This study highlights the importance of evaluating structural damage at multiple scales for a more complete characterization of the damage, and particularly shows the importance of microscale observations for identifying spallation-induced damage.

  5. The concept of explosives malfunctioning in rock blasting

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Q.

    1993-11-01

    The purpose is to identify the critical conditions that cause malfunctioning for some commonly used explosives. Experiments are described that measure sympathetic detonation, desensitization, and cut-offs for two variables: spacing and delay. Explosive malfunctioning is depicted on a delay spacing chart that has different regions. On the chart, the shape and size of each region can vary from one explosive to another. Results are presented from over 70 blasts, that were conducted in the underground drift at the CANMET Experimental Mine, to identify the malfunctioning characteristics of specific emulsion, water gel, and dynamite explosives. For each experiment, two parallel blastholes (with diameter of 32 mm and depth of 1.7 m) were drilled downwards, and full coupling was achieved. The results are presented for the three types of explosives tested. 11 refs., 7 figs.

  6. Critical flux determination by flux-stepping

    DEFF Research Database (Denmark)

    Beier, Søren; Jonsson, Gunnar Eigil

    2010-01-01

    In membrane filtration related scientific literature, often step-by-step determined critical fluxes are reported. Using a dynamic microfiltration device, it is shown that critical fluxes determined from two different flux-stepping methods are dependent upon operational parameters such as step...... length, step height, and.flux start level. Filtrating 8 kg/m(3) yeast cell suspensions by a vibrating 0.45 x 10(-6) m pore size microfiltration hollow fiber module, critical fluxes from 5.6 x 10(-6) to 1.2 x 10(-5) m/s have been measured using various step lengths from 300 to 1200 seconds. Thus......, such values are more or less useless in itself as critical flux predictors, and constant flux verification experiments have to be conducted to check if the determined critical fluxes call predict sustainable flux regimes. However, it is shown that using the step-by-step predicted critical fluxes as start...

  7. Vapour cloud explosion hazard greater with light feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Windebank, C.S.

    1980-03-03

    Because lighter chemical feedstocks such as propylene and butylenes are more reactive than LPG's they pose a greater risk of vapor cloud explosion, particularly during their transport. According to C.S. Windebank (Insurance Tech. Bur.), percussive unconfined vapor cloud explosions (PUVCE's) do not usually occur below the ten-ton threshold for saturated hydrocarbons but can occur well below this threshold in the case of unsaturated hydrocarbons such as propylene and butylenes. Boiling liquid expanding vapor explosions (BLEVE's) are more likely to be ''hot'' (i.e., the original explosion is associated with fire) than ''cold'' in the case of unsaturated hydrocarbons. No PUVCE or BLEVE incident has been reported in the UK. In the US, 16 out of 20 incidents recorded between 1970 and 1975 were related to chemical feedstocks, including propylene and butylenes, and only 4 were LPG-related. The average losses were $20 million per explosion. Between 1968 and 1978, 8% of LPG pipeline spillages led to explosions.

  8. Progress in the development of explosives materials detectors

    International Nuclear Information System (INIS)

    Williams, W.D.; Conrad, F.J.; Sandlin, L.L.; Burrows, T.A.

    1978-01-01

    Five hand-held explosives vapor detectors (Elscint Model EXD-2, ITI Model 70, Leigh-Marsland Model S-201, Pye Dynamics Model PD.2.A, and Xonics Model GC-710) were evaluated for sensitivity to a variety of explosives, identification of false alarm agents, and general performance and maintenance characteristics. The results of this evaluation, as presented, indicate that there is no single explosives detector which is best-suited for use at all nuclear facilities. Rather, there are several site-specific elements which must be considered when choosing an explosives detector. There are several new explosives detector technologies being developed which will out-perform existing commercial equipment. Some of these new detectors may be commercially available by the end of fiscal year 1980 and will be cost-effective to purchase and operate. The following areas of explosives detection research are discussed: nitrogen-phosphorous detectors, plasma chromatography, mass spectroscopy, small animal olfactory, vapor preconcentration, nuclear quadrupole resonance, far infrared radiation imaging, nuclear magnetic resonance, thermal neutron activation, and computerized tomography

  9. Dual compression is not an uncommon type of iliac vein compression syndrome.

    Science.gov (United States)

    Shi, Wan-Yin; Gu, Jian-Ping; Liu, Chang-Jian; Lou, Wen-Sheng; He, Xu

    2017-09-01

    Typical iliac vein compression syndrome (IVCS) is characterized by compression of left common iliac vein (LCIV) by the overlying right common iliac artery (RCIA). We described an underestimated type of IVCS with dual compression by right and left common iliac arteries (LCIA) simultaneously. Thirty-one patients with IVCS were retrospectively included. All patients received trans-catheter venography and computed tomography (CT) examinations for diagnosing and evaluating IVCS. Late venography and reconstructed CT were used for evaluating the anatomical relationship among LCIV, RCIA and LCIA. Imaging manifestations as well as demographic data were collected and evaluated by two experienced radiologists. Sole and dual compression were found in 32.3% (n = 10) and 67.7% (n = 21) of 31 patients respectively. No statistical differences existed between them in terms of age, gender, LCIV diameter at the maximum compression point, pressure gradient across stenosis, and the percentage of compression level. On CT and venography, sole compression was commonly presented with a longitudinal compression at the orifice of LCIV while dual compression was usually presented as two types: one had a lengthy stenosis along the upper side of LCIV and the other was manifested by a longitudinal compression near to the orifice of external iliac vein. The presence of dual compression seemed significantly correlated with the tortuous LCIA (p = 0.006). Left common iliac vein can be presented by dual compression. This type of compression has typical manifestations on late venography and CT.

  10. Nuclear Explosions 1945-1998

    Energy Technology Data Exchange (ETDEWEB)

    Bergkvist, Nils-Olov; Ferm, Ragnhild

    2000-07-01

    The main part of this report is a list of nuclear explosions conducted by the United States, the Soviet Union, the United Kingdom, France, China, India and Pakistan in 1945-98. The list includes all known nuclear test explosions and is compiled from a variety of sources including officially published information from the USA, Russia and France. The details given for each explosion (date, origin time, location, yield, type, etc.) are often compiled from more than one source because the individual sources do not give complete information. The report includes a short background to nuclear testing and provides brief information on the Comprehensive Nuclear-Test-Ban Treaty and the verification regime now being established to verify compliance with the treaty. It also summarizes nuclear testing country by country. The list should be used with some caution because its compilation from a variety of sources means that some of the data could be incorrect. This report is the result of cooperation between the Defence Research Establishment (FOA) and the Stockholm International Peace Research Institute (SIPRI)

  11. 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.

  12. Dark matter annihilation in the milky way galaxy: effects of baryonic compression.

    Science.gov (United States)

    Prada, F; Klypin, A; Flix, J; Martínez, M; Simonneau, E

    2004-12-10

    If the dark matter (DM), which is considered to constitute most of the mass of galaxies, is made of supersymmetric particles, the central region of our Galaxy should emit gamma rays produced by their annihilation. We use detailed models of the Milky Way to make accurate estimates of continuum gamma-ray fluxes. We argue that the most important effect, which was previously neglected, is the compression of the dark matter due to the infall of baryons to the galactic center: it boosts the expected signal by a factor 1000. To illustrate this effect, we computed the expected gamma fluxes in the minimal supergravity scenario. Our models predict that the signal could be detected at high confidence levels by imaging atmospheric C erenkov telescopes assuming that neutralinos make up most of the DM in the Universe.

  13. 27 CFR 555.180 - Prohibitions relating to unmarked plastic explosives.

    Science.gov (United States)

    2010-04-01

    ... unmarked plastic explosives. 555.180 Section 555.180 Alcohol, Tobacco Products, and Firearms BUREAU OF... Marking of Plastic Explosives § 555.180 Prohibitions relating to unmarked plastic explosives. (a) No person shall manufacture any plastic explosive that does not contain a detection agent. (b) No person...

  14. Modelling of vapour explosion in stratified geometrie

    International Nuclear Information System (INIS)

    Picchi, St.

    1999-01-01

    When a hot liquid comes into contact with a colder volatile liquid, one can obtain in some conditions an explosive vaporization, told vapour explosion, whose consequences can be important on neighbouring structures. This explosion needs the intimate mixing and the fine fragmentation between the two liquids. In a stratified vapour explosion, these two liquids are initially superposed and separated by a vapor film. A triggering of the explosion can induce a propagation of this along the film. A study of experimental results and existent models has allowed to retain the following main points: - the explosion propagation is due to a pressure wave propagating through the medium; - the mixing is due to the development of Kelvin-Helmholtz instabilities induced by the shear velocity between the two liquids behind the pressure wave. The presence of the vapour in the volatile liquid explains experimental propagation velocity and the velocity difference between the two fluids at the pressure wave crossing. A first model has been proposed by Brayer in 1994 in order to describe the fragmentation and the mixing of the two fluids. Results of the author do not show explosion propagation. We have therefore built a new mixing-fragmentation model based on the atomization phenomenon that develops itself during the pressure wave crossing. We have also taken into account the transient aspect of the heat transfer between fuel drops and the volatile liquid, and elaborated a model of transient heat transfer. These two models have been introduced in a multi-components, thermal, hydraulic code, MC3D. Results of calculation show a qualitative and quantitative agreement with experimental results and confirm basic options of the model. (author)

  15. Behavior of explosion debris clouds

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    In the normal course of events the behavior of debris clouds created by explosions will be of little concern to the atomic energy industry. However, two situations, one of them actual and one postulated, exist where the rise and spread of explosion clouds can affect site operations. The actual occurrence would be the detonation of nuclear weapons and the resultant release and transport of radioactive debris across the various atomic energy installations. Although the activity of the diffusing cloud is not of biological concern, it may still be sufficiently above background to play havoc with the normal readings of sensitive monitoring instruments. If it were not known that these anomalous readings resulted from explosion debris, considerable time and expense might be required for on-site testing and tracing. Fortunately it is usually possible, with the use of meteorological data and forecasts, to predict when individual sites are affected by nuclear weapon debris effects. The formation rise, and diffusion of weapon clouds will be discussed. The explosion of an atomic reactor is the postulated situation. It is common practice in reactor hazard analysis to assume a combination of circumstances which might result in a nuclear incident with a release of material to the atmosphere. It is not within the scope of this report to examine the manifold plausibilities that might lead to an explosion or the possible methods of release of gaseous and/or particulates from such an occurrence. However, if the information of a cloud is assumed and some idea of its energy content is obtainable, estimates of the cloud behavior in the atmosphere can be made

  16. Explosive Components Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The 98,000 square foot Explosive Components Facility (ECF) is a state-of-the-art facility that provides a full-range of chemical, material, and performance analysis...

  17. 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.

  18. CFD analysis of gas explosions vented through relief pipes.

    Science.gov (United States)

    Ferrara, G; Di Benedetto, A; Salzano, E; Russo, G

    2006-09-21

    Vent devices for gas and dust explosions are often ducted to safe locations by means of relief pipes. However, the presence of the duct increases the severity of explosion if compared to simply vented vessels (i.e. compared to cases where no duct is present). Besides, the identification of the key phenomena controlling the violence of explosion has not yet been gained. Multidimensional models coupling, mass, momentum and energy conservation equations can be valuable tools for the analysis of such complex explosion phenomena. In this work, gas explosions vented through ducts have been modelled by a two-dimensional (2D) axi-symmetric computational fluid dynamic (CFD) model based on the unsteady Reynolds Averaged Navier Stokes (RANS) approach in which the laminar, flamelet and distributed combustion models have been implemented. Numerical test have been carried out by varying ignition position, duct diameter and length. Results have evidenced that the severity of ducted explosions is mainly driven by the vigorous secondary explosion occurring in the duct (burn-up) rather than by the duct flow resistance or acoustic enhancement. Moreover, it has been found out that the burn-up affects explosion severity due to the reduction of venting rate rather than to the burning rate enhancement through turbulization.

  19. Surface and body waves from surface and underground explosions

    International Nuclear Information System (INIS)

    Kusubov, A.S.

    1976-06-01

    The characteristics of surface and ground waves were recorded for surface and underground explosions up to 100 tons and 40 kt in magnitude, respectively, and a preliminary analysis of these results is presented. The experiments were conducted at NTS in the Yucca Flats, Nevada. Ground motions were detected with triaxial geophones along seismic lines extending up to 16 miles from the point of explosions. A comparison of Rayleigh waves generated by surface and underground explosions in the same lake bed is presented indicating a very different behavior of surface and ground waves from the two types of explosions. The magnitude of the transverse wave for surface shots was smaller by a factor of two than its longitudinal counterpart. The dependence of apparent periods on the blast energy was not apparent at a fixed distance from the explosions. Changes in the apparent period with distance for both types of explosion are compared indicating a strong layering effect of the lake bed. The ground motion study was complimented by excavation of cavities generated by the explosions

  20. Charging method of water hole with ANFO explosive

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Susumu

    1988-02-28

    It has been investigated how to charge a water hole with an inexpensive explosive for blasting. An experiment was made using the combination of a plasticized resin hose and the ANFO charger as the method for making the most of the ANFO explosive aiming at charging a hole with the explosive at a low cost without damaging the hole wall. The experimental result indicates that any water hole with spring water can be charged with the explosive using the ANFO charger combined with the plasticized resin hose. The method is superior to conventional methods in cost and workability because the working atmosphere is not aggravated and the hole wall is not damaged without using an expensive vacuum collector. Charging a blasting hole 165 mm or less in diameter with the explosive will be investigated for commercialization in future. (4 figs)

  1. The vapor pressures of explosives

    Energy Technology Data Exchange (ETDEWEB)

    Ewing, Robert G.; Waltman, Melanie J.; Atkinson, David A.; Grate, Jay W.; Hotchkiss, Peter

    2013-01-05

    The vapor pressures of many explosive compounds are extremely low and thus determining accurate values proves difficult. Many researchers, using a variety of methods, have measured and reported the vapor pressures of explosives compounds at single temperatures, or as a function of temperature using vapor pressure equations. There are large variations in reported vapor pressures for many of these compounds, and some errors exist within individual papers. This article provides a review of explosive vapor pressures and describes the methods used to determine them. We have compiled primary vapor pressure relationships traceable to the original citations and include the temperature ranges for which they have been determined. Corrected values are reported as needed and described in the text. In addition, after critically examining the available data, we calculate and tabulate vapor pressures at 25 °C.

  2. "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.

  3. New directions in the science and technology of advanced sheet explosive formulations and the key energetic materials used in the processing of sheet explosives: Emerging trends.

    Science.gov (United States)

    Talawar, M B; Jangid, S K; Nath, T; Sinha, R K; Asthana, S N

    2015-12-30

    This review presents the work carried out by the international community in the area of sheet explosive formulations and its applications in various systems. The sheet explosive is also named as PBXs and is a composite material in which solid explosive particles like RDX, HMX or PETN are dispersed in a polymeric matrix, forms a flexible material that can be rolled/cut into sheet form which can be applied to any complex contour. The designed sheet explosive must possess characteristic properties such as flexible, cuttable, water proof, easily initiable, and safe handling. The sheet explosives are being used for protecting tanks (ERA), light combat vehicle and futuristic infantry carrier vehicle from different attacking war heads etc. Besides, sheet explosives find wide applications in demolition of bridges, ships, cutting and metal cladding. This review also covers the aspects such as risks and hazard analysis during the processing of sheet explosive formulations, effect of ageing on sheet explosives, detection and analysis of sheet explosive ingredients and the R&D efforts of Indian researchers in the development of sheet explosive formulations. To the best of our knowledge, there has been no review article published in the literature in the area of sheet explosives. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Explosive performance on the non-proliferation experiment

    Energy Technology Data Exchange (ETDEWEB)

    McKown, T.O.

    1994-03-01

    The non-proliferation experiment, originally called the chemical kiloton experiment, was planned and executed by Lawrence Livermore National Laboratory to investigate the seismic yield relationship and distinguishing seismic signals between a nuclear event and a large mass conventional explosion. The Los Alamos National Laboratory planned and conducted experiments to further their studies of the source function for signals observed seismically. 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 system was used to investigate the explosive initiation and to determine the detonation velocities in multiple levels and in numerous directions. A description of the CORRTEX experiments fielded, a review of the data obtained and some interpretations of the data are reported.

  5. Explosive composition with group VIII metal nitroso halide getter

    Science.gov (United States)

    Walker, F.E.; Wasley, R.J.

    1982-06-22

    An improved explosive composition is disclosed and comprises a major portion of an explosive having a detonation velocity between about 1,500 and 10,000 meters per second and a minor amount of a getter additive comprising a non-explosive compound or mixture of non-explosive compounds capable of chemically reacting with free radicals or ions under shock initiation conditions of 2,000 calories/cm[sup 2] or less of energy fluence.

  6. 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

  7. Pulse Compression of Phase-matched High Harmonic Pulses from a Time-Delay Compensated Monochromator

    Directory of Open Access Journals (Sweden)

    Ito Motohiko

    2013-03-01

    Full Text Available Pulse compression of single 32.6-eV high harmonic pulses from a time-delay compensated monochromator was demonstrated down to 11±3 fs by compensating the pulse front tilt. The photon flux was intensified up to 5.7×109 photons/s on target by implementing high harmonic generation under a phase matching condition in a hollow fiber used for increasing the interaction length.

  8. Thermodynamic bounds for existence of normal shock in compressible fluid flow in pipes

    Directory of Open Access Journals (Sweden)

    SERGIO COLLE

    Full Text Available Abstract The present paper is concerned with the thermodynamic theory of the normal shock in compressible fluid flow in pipes, in the lights of the pioneering works of Lord Rayleigh and G. Fanno. The theory of normal shock in pipes is currently presented in terms of the Rayleigh and Fanno curves, which are shown to cross each other in two points, one corresponding to a subsonic flow and the other corresponding to a supersonic flow. It is proposed in this paper a novel differential identity, which relates the energy flux density, the linear momentum flux density, and the entropy, for constant mass flow density. The identity so obtained is used to establish a theorem, which shows that Rayleigh and Fanno curves become tangent to each other at a single sonic point. At the sonic point the entropy reaches a maximum, either as a function of the pressure and the energy density flux or as a function of the pressure and the linear momentum density flux. A Second Law analysis is also presented, which is fully independent of the Second Law analysis based on the Rankine-Hugoniot adiabatic carried out by Landau and Lifshitz (1959.

  9. A volume-filtered formulation to capture particle-shock interactions in multiphase compressible flows

    Science.gov (United States)

    Shallcross, Gregory; Capecelatro, Jesse

    2017-11-01

    Compressible particle-laden flows are common in engineering systems. Applications include but are not limited to water injection in high-speed jet flows for noise suppression, rocket-plume surface interactions during planetary landing, and explosions during coal mining operations. Numerically, it is challenging to capture these interactions due to the wide range of length and time scales. Additionally, there are many forms of the multiphase compressible flow equations with volume fraction effects, some of which are conflicting in nature. The purpose of this presentation is to develop the capability to accurately capture particle-shock interactions in systems with a large number of particles from dense to dilute regimes. A thorough derivation of the volume filtered equations is presented. The volume filtered equations are then implemented in a high-order, energy-stable Eulerian-Lagrangian framework. We show this framework is capable of decoupling the fluid mesh from the particle size, enabling arbitrary particle size distributions in the presence of shocks. The proposed method is then assessed against particle-laden shock tube data. Quantities of interest include fluid-phase pressure profiles and particle spreading rates. The effect of collisions in 2D and 3D are also evaluated.

  10. 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.

  11. Application of Compressible Volume of Fluid Model in Simulating the Impact and Solidification of Hollow Spherical ZrO2 Droplet on a Surface

    Science.gov (United States)

    Safaei, Hadi; Emami, Mohsen Davazdah; Jazi, Hamidreza Salimi; Mostaghimi, Javad

    2017-12-01

    Applications of hollow spherical particles in thermal spraying process have been developed in recent years, accompanied by attempts in the form of experimental and numerical studies to better understand the process of impact of a hollow droplet on a surface. During such process, volume and density of the trapped gas inside droplet change. The numerical models should be able to simulate such changes and their consequent effects. The aim of this study is to numerically simulate the impact of a hollow ZrO2 droplet on a flat surface using the volume of fluid technique for compressible flows. An open-source, finite-volume-based CFD code was used to perform the simulations, where appropriate subprograms were added to handle the studied cases. Simulation results were compared with the available experimental data. Results showed that at high impact velocities ( U 0 > 100 m/s), the compression of trapped gas inside droplet played a significant role in the impact dynamics. In such velocities, the droplet splashed explosively. Compressibility effects result in a more porous splat, compared to the corresponding incompressible model. Moreover, the compressible model predicted a higher spread factor than the incompressible model, due to planetary structure of the splat.

  12. Supersensitive fingerprinting of explosives by chemically modified nanosensors arrays

    Science.gov (United States)

    Lichtenstein, Amir; Havivi, Ehud; Shacham, Ronen; Hahamy, Ehud; Leibovich, Ronit; Pevzner, Alexander; Krivitsky, Vadim; Davivi, Guy; Presman, Igor; Elnathan, Roey; Engel, Yoni; Flaxer, Eli; Patolsky, Fernando

    2014-06-01

    The capability to detect traces of explosives sensitively, selectively and rapidly could be of great benefit for applications relating to civilian national security and military needs. Here, we show that, when chemically modified in a multiplexed mode, nanoelectrical devices arrays enable the supersensitive discriminative detection of explosive species. The fingerprinting of explosives is achieved by pattern recognizing the inherent kinetics, and thermodynamics, of interaction between the chemically modified nanosensors array and the molecular analytes under test. This platform allows for the rapid detection of explosives, from air collected samples, down to the parts-per-quadrillion concentration range, and represents the first nanotechnology-inspired demonstration on the selective supersensitive detection of explosives, including the nitro- and peroxide-derivatives, on a single electronic platform. Furthermore, the ultrahigh sensitivity displayed by our platform may allow the remote detection of various explosives, a task unachieved by existing detection technologies.

  13. Thermal explosion models

    Energy Technology Data Exchange (ETDEWEB)

    Ping, Tso Chin [Malaya Univ., Kuala Lumpur (Malaysia)

    1984-12-01

    The phenomenon of thermal explosion arises in several important safety problems, yet scientists are still baffled by its origin. This article reviews some of the models that have been proposed to explain the phenomenon.

  14. Boosted Fast Flux Loop Alternative Cooling Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Glen R. Longhurst; Donna Post Guillen; James R. Parry; Douglas L. Porter; Bruce W. Wallace

    2007-08-01

    The Gas Test Loop (GTL) Project was instituted to develop the means for conducting fast neutron irradiation tests in a domestic radiation facility. It made use of booster fuel to achieve the high neutron flux, a hafnium thermal neutron absorber to attain the high fast-to-thermal flux ratio, a mixed gas temperature control system for maintaining experiment temperatures, and a compressed gas cooling system to remove heat from the experiment capsules and the hafnium thermal neutron absorber. This GTL system was determined to provide a fast (E > 0.1 MeV) flux greater than 1.0E+15 n/cm2-s with a fast-to-thermal flux ratio in the vicinity of 40. However, the estimated system acquisition cost from earlier studies was deemed to be high. That cost was strongly influenced by the compressed gas cooling system for experiment heat removal. Designers were challenged to find a less expensive way to achieve the required cooling. This report documents the results of the investigation leading to an alternatively cooled configuration, referred to now as the Boosted Fast Flux Loop (BFFL). This configuration relies on a composite material comprised of hafnium aluminide (Al3Hf) in an aluminum matrix to transfer heat from the experiment to pressurized water cooling channels while at the same time providing absorption of thermal neutrons. Investigations into the performance this configuration might achieve showed that it should perform at least as well as its gas-cooled predecessor. Physics calculations indicated that the fast neutron flux averaged over the central 40 cm (16 inches) relative to ATR core mid-plane in irradiation spaces would be about 1.04E+15 n/cm2-s. The fast-to-thermal flux ratio would be in excess of 40. Further, the particular configuration of cooling channels was relatively unimportant compared with the total amount of water in the apparatus in determining performance. Thermal analyses conducted on a candidate configuration showed the design of the water coolant and

  15. Current trends in development of explosives in world mining

    Energy Technology Data Exchange (ETDEWEB)

    Dobnikar, S.

    1987-01-01

    Surveys development of manufacturing industrial explosives in the 19th and 20th centuries, from first use of black powder, ammonium nitrate and TNT to the use of ANFO, slurries and water gel type explosives. Achievements of explosive producers with worldwide reputation (Ireco Chemicals, Du Pont, Atlas Powder Chemical, Nitro Nobel, Nippon Oil and Fats Co., Thermex Energy Co.) for manufacturing safe, reliable explosives used in surface and underground coal and ore mining (including gassy coal mines) and for quarrying are mentioned. Main characteristics of IREMITE, IREGEL, TOVEX, POURVEX, DRIVEX, Detagel, ANFO (both gel- and emulsion-type), Emulgite and Emulite are presented. A critical opinion about future trends in industrial explosive development is given. 10 refs., 7 tabs.

  16. Explosion-Induced Implosions of Cylindrical Shell Structures

    Science.gov (United States)

    Ikeda, C. M.; Duncan, J. H.

    2010-11-01

    An experimental study of the explosion-induced implosion of cylindrical shell structures in a high-pressure water environment was performed. The shell structures are filled with air at atmospheric pressure and are placed in a large water-filled pressure vessel. The vessel is then pressurized to various levels P∞=αPc, where Pc is the natural implosion pressure of the model and α is a factor that ranges from 0.1 to 0.9. An explosive is then set off at various standoff distances, d, from the model center line, where d varies from R to 10R and R is the maximum radius of the explosion bubble. High-speed photography (27,000 fps) was used to observe the explosion and resulting shell structure implosion. High-frequency underwater blast sensors recorded dynamic pressure waves at 6 positions. The cylindrical models were made from aluminum (diameter D = 39.1 mm, wall thickness t = 0.89 mm, length L = 240 mm) and brass (D = 16.7 mm, t = 0.36 mm, L=152 mm) tubes. The pressure records are interpreted in light of the high-speed movies. It is found that the implosion is induced by two mechanisms: the shockwave generated by the explosion and the jet formed during the explosion-bubble collapse. Whether an implosion is caused by the shockwave or the jet depends on the maximum bubble diameter and the standoff distance.

  17. 49 CFR 173.60 - General packaging requirements for explosives.

    Science.gov (United States)

    2010-10-01

    ... explosives contained in the package, so that neither interaction between the explosives and the packaging... 49 Transportation 2 2010-10-01 2010-10-01 false General packaging requirements for explosives. 173...-GENERAL REQUIREMENTS FOR SHIPMENTS AND PACKAGINGS Definitions, Classification and Packaging for Class 1...

  18. 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

  19. MMS observations of guide field reconnection at the interface between colliding reconnection jets inside flux rope-like structures at the magnetopause

    Science.gov (United States)

    Oieroset, M.; Phan, T.; Haggerty, C. C.; Shay, M.; Eastwood, J. P.; Gershman, D. J.; Drake, J. F.; Fujimoto, M.; Ergun, R.; Mozer, F.; Oka, M.; Torbert, R. B.; Burch, J. L.; Wang, S.; Chen, L. J.; Swisdak, M.; Pollock, C. J.; Dorelli, J.; Fuselier, S. A.; Lavraud, B.; Kacem, I.; Giles, B. L.; Moore, T. E.; Saito, Y.; Avanov, L. A.; Paterson, W. R.; Strangeway, R. J.; Schwartz, S. J.; Khotyaintsev, Y. V.; Lindqvist, P. A.; Malakit, K.

    2017-12-01

    The formation and evolution of magnetic flux ropes is of critical importance for a number of collisionless plasma phenomena. At the dayside magnetopause flux rope-like structures can form between two X-lines. The two X-lines produce converging plasma jets. At the interface between the colliding jets a compressed current sheet can form, which in turn can undergo reconnection. We present MMS observations of the exhaust and diffusion region of such reconnection.

  20. Aluminum-Enhanced Underwater Electrical Discharges for Steam Explosion Triggering

    International Nuclear Information System (INIS)

    HOGELAND, STEVE R.; NELSON, LLOYD S.; ROTH, THOMAS CHRISTOPHER

    1999-01-01

    For a number of years, we have been initiating steam explosions of single drops of molten materials with pressure and flow (bubble growth) transients generated by discharging a capacitor bank through gold bridgewires placed underwater. Recent experimental and theoretical advances in the field of steam explosions, however, have made it important to substantially increase these relatively mild transients in water without using high explosives, if possible. To do this with the same capacitor bank, we have discharged similar energies through tiny strips of aluminum foil submerged in water. By replacing the gold wires with the aluminum strips, we were able to add the energy of the aluminum-water combustion to that normally deposited electrically by the bridgewire explosion in water. The chemical enhancement of the explosive characteristics of the discharges was substantial: when the same electrical energies were discharged through the aluminum strips, peak pressures increased as much as 12-fold and maximum bubble volumes as much as 5-fold above those generated with the gold wires. For given weights of aluminum, the magnitudes of both parameters appeared to exceed those produced by the underwater explosion of equivalent weights of high explosives

  1. Thermal explosion models

    International Nuclear Information System (INIS)

    Tso Chin Ping

    1984-01-01

    The phenomenon of thermal explosion arises in several important safety problems, yet scientists are still baffled by its origin. This article reviews some of the models that have been proposed to explain the phenomenon. (author)

  2. Supernova neutrinos and explosive nucleosynthesis

    Science.gov (United States)

    Kajino, T.; Aoki, W.; Cheoun, M.-K.; Hayakawa, T.; Hidaka, J.; Hirai, Y.; Mathews, G. J.; Nakamura, K.; Shibagaki, S.; Suzuki, T.

    2014-05-01

    Core-collapse supernovae eject huge amount of flux of energetic neutrinos. We studied the explosive nucleosyn-thesis in supernovae and found that several isotopes 7Li, 11B, 92Nb, 138La and 180Ta as well as r-process nuclei are affected by the neutrino interactions. The abundance of these isotopes therefore depends strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. We discuss first how to determine the neutrino temperatures in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. We then study the effects of neutrino oscillation on their abundances, and propose a novel method to determine the still unknown neutrino oscillation parameters, mass hierarchy and θ13, simultaneously. There is recent evidence that SiC X grains from the Murchison meteorite may contain supernova-produced light elements 11B and 7Li encapsulated in the presolar grains. Combining the recent experimental constraints on θ13, we show that our method sug-gests at a marginal preference for an inverted neutrino mass hierarchy. Finally, we discuss supernova relic neutrinos that may indicate the softness of the equation of state (EoS) of nuclear matter as well as adiabatic conditions of the neutrino oscillation.

  3. Supernova neutrinos and explosive nucleosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Kajino, T. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan and Department of Astronomy, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan); Aoki, W. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Cheoun, M.-K. [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Hayakawa, T. [Japan Atomic Energy Agency, Shirakara-Shirane 2-4, Tokai-mura, Ibaraki 319-1195 (Japan); Hidaka, J.; Hirai, Y.; Shibagaki, S. [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Mathews, G. J. [Center for Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Nakamura, K. [Faculty of Science and Engineering, Waseda University, Ohkubo 3-4-1, Shinjuku, Tokyo 169-8555 (Japan); Suzuki, T. [Department of Physics, College of Humanities and Sciences, Nihon University, Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan)

    2014-05-09

    Core-collapse supernovae eject huge amount of flux of energetic neutrinos. We studied the explosive nucleosyn-thesis in supernovae and found that several isotopes {sup 7}Li, {sup 11}B, {sup 92}Nb, {sup 138}La and {sup 180}Ta as well as r-process nuclei are affected by the neutrino interactions. The abundance of these isotopes therefore depends strongly on the neutrino flavor oscillation due to the Mikheyev-Smirnov-Wolfenstein (MSW) effect. We discuss first how to determine the neutrino temperatures in order to explain the observed solar system abundances of these isotopes, combined with Galactic chemical evolution of the light nuclei and the heavy r-process elements. We then study the effects of neutrino oscillation on their abundances, and propose a novel method to determine the still unknown neutrino oscillation parameters, mass hierarchy and θ{sub 13}, simultaneously. There is recent evidence that SiC X grains from the Murchison meteorite may contain supernova-produced light elements {sup 11}B and {sup 7}Li encapsulated in the presolar grains. Combining the recent experimental constraints on θ{sub 13}, we show that our method sug-gests at a marginal preference for an inverted neutrino mass hierarchy. Finally, we discuss supernova relic neutrinos that may indicate the softness of the equation of state (EoS) of nuclear matter as well as adiabatic conditions of the neutrino oscillation.

  4. HSE assessment of explosion risk analysis in offshore safety cases

    Energy Technology Data Exchange (ETDEWEB)

    Brighton, P.W.M.; Fearnley, P.J.; Brearley, I.G. [Health and Safety Executive, Bootle (United Kingdom). Offshore Safety Div.

    1995-12-31

    In the past two years HSE has assessed around 250 Safety Cases for offshore oil and gas installations, building up a unique overview of the current state of the art on fire and explosion risk assessment. This paper reviews the explosion risk methods employed, focusing on the aspects causing most difficulty for assessment and acceptance of Safety Cases. Prediction of overpressures in offshore explosions has been intensively researched in recent years but the justification of the means of prevention, control and mitigation of explosions often depends on much additional analysis of the frequency and damage potential of explosions. This involves a number of factors, the five usually considered being: leak sizes; gas dispersion; ignition probabilities; the frequency distribution of explosion strength; and the prediction of explosion damage. Sources of major uncertainty in these factors and their implications for practical risk management decisions are discussed. (author)

  5. SN 1987A gamma-ray line profiles and fluxes

    International Nuclear Information System (INIS)

    Bussard, R.W.; Burrows, A.; The, L.S.

    1989-01-01

    Results for the time dependence of the line profiles and integrated fluxes for the 0.847 and 1.238 MeV gamma rays from the decay of cobalt to excited states of iron are presented for several models of the ejectum of SN 1987A. The relatively early detection of these lines has led several workers to propose that some degree of mixing has brought the cobalt closer to the electron-scattering photosphere than standard models predict. Constraints on the amount of mixing from recent observations are discussed using calculations of the energy-integrated line fluxes as a function of time since the explosion. Implications for the line profiles at various times are considered, and it is found that they show strong time dependences and are quite sensitive to the degree of mixing. The two primary effects are Doppler broadening due to the presence of radioactive material at higher velocities and a strong blueshift at early times resulting from optical depth effects. These results have important implications for gamma-ray observations, especially with high-resolution germanium instruments. Finally, the consequences of the fragmentation of the debris for the early emergence of the gamma-ray lines are considered. 32 refs

  6. Variations of electron fluxes in the outer radiation belt near the boundary of a trapping region during substorms

    International Nuclear Information System (INIS)

    Ginzburg, E.A.; Malyshev, A.B.

    1979-01-01

    Variations of electron fluxes with the energy Esub(e) > 0.7 MeV have been investigated near the high-latitude boundary of electron trapping region in the night and day sections of the magnetosphere. It is found that during substorms the natural changes of the structure of electron fluxes take place. On the night side of the magnetosphere after the flux boundary drift to the equator at the preliminary phase, its sharp drift to the pole at the explosion phase takes place with further slow ( during 1-2 hours) shift to the initial position. The boundary position reconstruction period coincide by duration with the life time of negative bays at magnetograms of the night section stations. On the day side the boundary of electron fluxes recorded drifts to the pole in 30-60 min after the beginning of the substorm exposion phase. The results obtained are interpreted within the framework of the theory of adiabatic drift of trapped electrons and their pitch-angular diffusion under the effect of very low frequency waves

  7. 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.

  8. Stability analysis and numerical simulation of a hard-core diffuse z pinch during compression with Atlas facility liner parameters

    Science.gov (United States)

    Siemon, R. E.; Atchison, W. L.; Awe, T.; Bauer, B. S.; Buyko, A. M.; Chernyshev, V. K.; Cowan, T. E.; Degnan, J. H.; Faehl, R. J.; Fuelling, S.; Garanin, S. F.; Goodrich, T.; Ivanovsky, A. V.; Lindemuth, I. R.; Makhin, V.; Mokhov, V. N.; Reinovsky, R. E.; Ryutov, D. D.; Scudder, D. W.; Taylor, T.; Yakubov, V. B.

    2005-09-01

    In the 'metal liner' approach to magnetized target fusion (MTF), a preheated magnetized plasma target is compressed to thermonuclear temperature and high density by externally driving the implosion of a flux conserving metal enclosure, or liner, which contains the plasma target. As in inertial confinement fusion, the principal fusion fuel heating mechanism is pdV work by the imploding enclosure, called a pusher in ICF. One possible MTF target, the hard-core diffuse z pinch, has been studied in MAGO experiments at VNIIEF and is one possible target being considered for experiments on the Atlas pulsed power facility. Numerical MHD simulations show two intriguing and helpful features of the diffuse z pinch with respect to compressional heating. First, in two-dimensional simulations the m = 0 interchange modes, arising from an unstable pressure profile, result in turbulent motions and self-organization into a stable pressure profile. The turbulence also gives rise to convective thermal transport, but the level of turbulence saturates at a finite level, and simulations show substantial heating during liner compression despite the turbulence. The second helpful feature is that pressure profile evolution during compression tends towards improved stability rather than instability when analysed according to the Kadomtsev criteria. A liner experiment is planned for Atlas to study compression of magnetic flux without plasma, as a first step. The Atlas geometry is compatible with a diffuse z pinch, and simulations of possible future experiments show that kiloelectronvolt temperatures and useful neutron production for diagnostic purposes should be possible if a suitable plasma injector is added to the Atlas facility.

  9. Physics of phenomena in the zone close to an underground nuclear explosion; Physique des phenomenes en zone proche des explosions nucleaires souterraines

    Energy Technology Data Exchange (ETDEWEB)

    Maury, J; Levret, C [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes

    1969-07-01

    After a description of the phenomenology of underground explosions, the basic laws governing the propagation in the ground of the energy produced by the explosion are given. The reports considers hydrodynamics, the mechanics of solids, the equations of state for solids and gases in the case of very high and medium pressures, and the dynamical strength of solids. These various elements make it possible to draw up a system of equations which define completely the changes with time of the shock-wave produced in the ground by the explosion. (authors) [French] Apres une description de la phenomenologie des explosions souterraines, on expose les lois fondamentales regissant la propagation dans le sol de l'energie degagee par l'explosion. L'expose comprend des developpements sur l'hydrodynamique, la mecanique des solides, les equations d'etat des solides et des gaz, aux tres fortes et moyennes pressions, et sur la resistance dynamique des solides. Ces differents elements permettent d'ecrire un systeme d'equations qui definissent completement l'evolution dans le temps de l'onde de choc emise dans le sol par l'explosion. (auteurs)

  10. Diagnostics for Pioneer I imploding plasma experiments

    International Nuclear Information System (INIS)

    Lee, P.H.Y.; Benjamin, R.F.; Brownell, J.H.

    1985-01-01

    The Pioneer I series of imploding plasma experiments are aimed at collapsing a thin aluminum foil with a multimegampere, submicrosecond electrical pulse produced by an explosive flux compression generator and fast plasma compression opening switch. Anticipated experimental conditions are bounded by implosion velocities of 2 x 10 7 cm/s and maximum plasma temperatures of 100 eV. A comprehensive array of diagnostics have been deployed to measure implosion symmetry (gated microchannel plate array and other time-resolved imaging), temperature of the imploding plasma (visible/uv spectroscopy), stagnation geometry (x-ray pinhole imaging), radiation emission characteristics at pinch (XRD's, fast bolometry), and electrical drive history (Rogowski loops, Faraday rotation current detectors, and capacitive voltage probes). Diagnostic performance is discussed and preliminary results are presented

  11. Shallow magma diversions during explosive diatreme-forming eruptions.

    Science.gov (United States)

    Le Corvec, Nicolas; Muirhead, James D; White, James D L

    2018-04-13

    The diversion of magma is an important mechanism that may lead to the relocation of a volcanic vent. Magma diversion is known to occur during explosive volcanic eruptions generating subterranean excavation and remobilization of country and volcanic rocks. However, feedbacks between explosive crater formation and intrusion processes have not been considered previously, despite their importance for understanding evolving hazards during volcanic eruptions. Here, we apply numerical modeling to test the impacts of excavation and subsequent infilling of diatreme structures on stress states and intrusion geometries during the formation of maar-diatreme complexes. Explosive excavation and infilling of diatremes affects local stress states which inhibits magma ascent and drives lateral diversion at various depths, which are expected to promote intra-diatreme explosions, host rock mixing, and vent migration. Our models demonstrate novel mechanisms explaining the generation of saucer-shaped sills, linked with magma diversion and enhanced intra-diatreme explosive fragmentation during maar-diatreme volcanism. Similar mechanisms will occur at other volcanic vents producing crater-forming eruptions.

  12. Saturation of superstorms and finite compressibility of the magnetosphere: Results of the magnetogram inversion technique and global PPMLR-MHD model

    Science.gov (United States)

    Mishin, V. V.; Mishin, V. M.; Karavaev, Yu.; Han, J. P.; Wang, C.

    2016-07-01

    We report on novel features of the saturation process of the polar cap magnetic flux and Poynting flux into the magnetosphere from the solar wind during three superstorms. In addition to the well-known effect of the interplanetary electric (Esw) and southward magnetic (interplanetary magnetic field (IMF) Bz) fields, we found that the saturation depends also on the solar wind ram pressure Pd. By means of the magnetogram inversion technique and a global MHD numerical model Piecewise Parabolic Method with a Lagrangian Remap, we explore the dependence of the magnetopause standoff distance on ram pressure and the southward IMF. Unlike earlier studies, in the considered superstorms both Pd and Bz achieve extreme values. As a result, we show that the compression rate of the dayside magnetosphere decreases with increasing Pd and the southward Bz, approaching very small values for extreme Pd ≥ 15 nPa and Bz ≤ -40 nT. This dependence suggests that finite compressibility of the magnetosphere controls saturation of superstorms.

  13. 49 CFR 1544.213 - Use of explosives detection systems.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 9 2010-10-01 2010-10-01 false Use of explosives detection systems. 1544.213...: AIR CARRIERS AND COMMERCIAL OPERATORS Operations § 1544.213 Use of explosives detection systems. (a... explosives detection system approved by TSA to screen checked baggage on international flights. (b) Signs and...

  14. Entropy Stable Wall Boundary Conditions for the Compressible Navier-Stokes Equations

    Science.gov (United States)

    Parsani, Matteo; Carpenter, Mark H.; Nielsen, Eric J.

    2014-01-01

    Non-linear entropy stability and a summation-by-parts framework are used to derive entropy stable wall boundary conditions for the compressible Navier-Stokes equations. A semi-discrete entropy estimate for the entire domain is achieved when the new boundary conditions are coupled with an entropy stable discrete interior operator. The data at the boundary are weakly imposed using a penalty flux approach and a simultaneous-approximation-term penalty technique. Although discontinuous spectral collocation operators are used herein for the purpose of demonstrating their robustness and efficacy, the new boundary conditions are compatible with any diagonal norm summation-by-parts spatial operator, including finite element, finite volume, finite difference, discontinuous Galerkin, and flux reconstruction schemes. The proposed boundary treatment is tested for three-dimensional subsonic and supersonic flows. The numerical computations corroborate the non-linear stability (entropy stability) and accuracy of the boundary conditions.

  15. Green primary explosives: 5-nitrotetrazolato-N2-ferrate hierarchies.

    Science.gov (United States)

    Huynh, My Hang V; Coburn, Michael D; Meyer, Thomas J; Wetzler, Modi

    2006-07-05

    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 military and civilian purposes continues to expand owing to variations in initiating method, chemical composition, quantity, sensitivity, explosive performance, and other necessary built-in mechanisms. Although the most widely used primaries contain toxic lead azide and lead styphnate, mixtures of thermally unstable primaries, like diazodinitrophenol and tetracene, or poisonous agents, like antimony sulfide and barium nitrate, are also used. Novel environmentally friendly primary explosives are expanded here to include cat[Fe(II)(NT)(3)(H(2)O)(3)], cat(2)[Fe(II)(NT)(4)(H(2)O)(2)], cat(3)[Fe(II)(NT)(5)(H(2)O)], and cat(4)[Fe(II)(NT)(6)] with cat = cation and NT(-) = 5-nitrotetrazolato-N(2). With available alkaline, alkaline earth, and organic cations as partners, four series of 5-nitrotetrazolato-N(2)-ferrate hierarchies have been prepared that provide a plethora of green primaries with diverse initiating sensitivity and explosive performance. They hold great promise for replacing not only toxic lead primaries but also thermally unstable primaries and poisonous agents. Strategies are also described for the systematic preparation of coordination complex green primaries based on appropriate selection of ligands, metals, and synthetic procedures. These strategies allow for maximum versatility in initiating sensitivity and explosive performance while retaining properties required for green primaries.

  16. Self-adjusting entropy-stable scheme for compressible Euler equations

    International Nuclear Information System (INIS)

    Cheng Xiao-Han; Nie Yu-Feng; Cai Li; Feng Jian-Hu; Luo Xiao-Yu

    2015-01-01

    In this work, a self-adjusting entropy-stable scheme is proposed for solving compressible Euler equations. The entropy-stable scheme is constructed by combining the entropy conservative flux with a suitable diffusion operator. The entropy has to be preserved in smooth solutions and be dissipated at shocks. To achieve this, a switch function, which is based on entropy variables, is employed to make the numerical diffusion term be automatically added around discontinuities. The resulting scheme is still entropy-stable. A number of numerical experiments illustrating the robustness and accuracy of the scheme are presented. From these numerical results, we observe a remarkable gain in accuracy. (paper)

  17. Optimization of Error-Bounded Lossy Compression for Hard-to-Compress HPC Data

    Energy Technology Data Exchange (ETDEWEB)

    Di, Sheng; Cappello, Franck

    2018-01-01

    Since today’s scientific applications are producing vast amounts of data, compressing them before storage/transmission is critical. Results of existing compressors show two types of HPC data sets: highly compressible and hard to compress. In this work, we carefully design and optimize the error-bounded lossy compression for hard-tocompress scientific data. We propose an optimized algorithm that can adaptively partition the HPC data into best-fit consecutive segments each having mutually close data values, such that the compression condition can be optimized. Another significant contribution is the optimization of shifting offset such that the XOR-leading-zero length between two consecutive unpredictable data points can be maximized. We finally devise an adaptive method to select the best-fit compressor at runtime for maximizing the compression factor. We evaluate our solution using 13 benchmarks based on real-world scientific problems, and we compare it with 9 other state-of-the-art compressors. Experiments show that our compressor can always guarantee the compression errors within the user-specified error bounds. Most importantly, our optimization can improve the compression factor effectively, by up to 49% for hard-tocompress data sets with similar compression/decompression time cost.

  18. Seismic and source characteristics of large chemical explosions. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Adushkin, V.V.; Kostuchenko, V.N.; Pernik, L.M.; Sultanov, D.D.; Zcikanovsky, V.I.

    1995-01-01

    From the very beginning of its arrangement in 1947, the Institute for Dynamics of the Geospheres RAS (former Special Sector of the Institute for physics of the Earth, RAS) was providing scientific observations of effects of nuclear explosions, as well as large-scale detonations of HE, on environment. This report presents principal results of instrumental observations obtained from various large-scale chemical explosions conducted in the Former-Soviet Union in the period of time from 1957 to 1989. Considering principal aim of the work, tamped and equivalent chemical explosions have been selected with total weights from several hundreds to several thousands ton. In particular, the selected explosions were aimed to study scaling law from excavation explosions, seismic effect of tamped explosions, and for dam construction for hydropower stations and soil melioration. Instrumental data on surface explosions of total weight in the same range aimed to test military technics and special objects are not included.

  19. The impact of chest compression rates on quality of chest compressions - a manikin study.

    Science.gov (United States)

    Field, Richard A; Soar, Jasmeet; Davies, Robin P; Akhtar, Naheed; Perkins, Gavin D

    2012-03-01

    Chest compressions are often performed at a variable rate during cardiopulmonary resuscitation (CPR). The effect of compression rate on other chest compression quality variables (compression depth, duty-cycle, leaning, performance decay over time) is unknown. This randomised controlled cross-over manikin study examined the effect of different compression rates on the other chest compression quality variables. Twenty healthcare professionals performed 2 min of continuous compressions on an instrumented manikin at rates of 80, 100, 120, 140 and 160 min(-1) in a random order. An electronic metronome was used to guide compression rate. Compression data were analysed by repeated measures ANOVA and are presented as mean (SD). Non-parametric data was analysed by Friedman test. At faster compression rates there were significant improvements in the number of compressions delivered (160(2) at 80 min(-1) vs. 312(13) compressions at 160 min(-1), P<0.001); and compression duty-cycle (43(6)% at 80 min(-1) vs. 50(7)% at 160 min(-1), P<0.001). This was at the cost of a significant reduction in compression depth (39.5(10)mm at 80 min(-1) vs. 34.5(11)mm at 160 min(-1), P<0.001); and earlier decay in compression quality (median decay point 120 s at 80 min(-1) vs. 40s at 160 min(-1), P<0.001). Additionally not all participants achieved the target rate (100% at 80 min(-1) vs. 70% at 160 min(-1)). Rates above 120 min(-1) had the greatest impact on reducing chest compression quality. For Guidelines 2005 trained rescuers, a chest compression rate of 100-120 min(-1) for 2 min is feasible whilst maintaining adequate chest compression quality in terms of depth, duty-cycle, leaning, and decay in compression performance. Further studies are needed to assess the impact of the Guidelines 2010 recommendation for deeper and faster chest compressions. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  20. Electronic cigarette explosions involving the oral cavity.

    Science.gov (United States)

    Harrison, Rebecca; Hicklin, David

    2016-11-01

    The use of electronic cigarettes (e-cigarettes) is a rapidly growing trend throughout the United States. E-cigarettes have been linked to the risk of causing explosion and fire. Data are limited on the associated health hazards of e-cigarette use, particularly long-term effects, and available information often presents conflicting conclusions. In addition, an e-cigarette explosion and fire can pose a unique treatment challenge to the dental care provider because the oral cavity may be affected heavily. In this particular case, the patient's injuries included intraoral burns, luxation injuries, and alveolar fractures. This case report aims to help clinicians gain an increased knowledge about e-cigarette design, use, and risks; discuss the risk of spontaneous failure and explosion of e-cigarettes with patients; and understand the treatment challenges posed by an e-cigarette explosion. Copyright © 2016 American Dental Association. Published by Elsevier Inc. All rights reserved.

  1. Local magnitudes of small contained explosions.

    Energy Technology Data Exchange (ETDEWEB)

    Chael, Eric Paul

    2009-12-01

    The relationship between explosive yield and seismic magnitude has been extensively studied for underground nuclear tests larger than about 1 kt. For monitoring smaller tests over local ranges (within 200 km), we need to know whether the available formulas can be extrapolated to much lower yields. Here, we review published information on amplitude decay with distance, and on the seismic magnitudes of industrial blasts and refraction explosions in the western U. S. Next we measure the magnitudes of some similar shots in the northeast. We find that local magnitudes ML of small, contained explosions are reasonably consistent with the magnitude-yield formulas developed for nuclear tests. These results are useful for estimating the detection performance of proposed local seismic networks.

  2. Criticality safety in high explosives dissolution

    International Nuclear Information System (INIS)

    Troyer, S.D.

    1997-01-01

    In 1992, an incident occurred at the Pantex Plant in which the cladding around a fissile material component (pit) cracked during dismantlement of the high explosives portion of a nuclear weapon. Although the event did not result in any significant contamination or personnel exposures, concerns about the incident led to the conclusion that the current dismantlement process was unacceptable. Options considered for redesign, dissolution tooling design considerations, dissolution tooling design features, and the analysis of the new dissolution tooling are summarized. The final tooling design developed incorporated a number of safety features and provides a simple, self-contained, low-maintenance method of high explosives removal for nuclear explosive dismantlement. Analyses demonstrate that the tooling design will remain subcritical under normal, abnormal, and credible accident scenarios. 1 fig

  3. An unstructured-mesh finite-volume MPDATA for compressible atmospheric dynamics

    International Nuclear Information System (INIS)

    Kühnlein, Christian; Smolarkiewicz, Piotr K.

    2017-01-01

    An advancement of the unstructured-mesh finite-volume MPDATA (Multidimensional Positive Definite Advection Transport Algorithm) is presented that formulates the error-compensative pseudo-velocity of the scheme to rely only on face-normal advective fluxes to the dual cells, in contrast to the full vector employed in previous implementations. This is essentially achieved by expressing the temporal truncation error underlying the pseudo-velocity in a form consistent with the flux-divergence of the governing conservation law. The development is especially important for integrating fluid dynamics equations on non-rectilinear meshes whenever face-normal advective mass fluxes are employed for transport compatible with mass continuity—the latter being essential for flux-form schemes. In particular, the proposed formulation enables large-time-step semi-implicit finite-volume integration of the compressible Euler equations using MPDATA on arbitrary hybrid computational meshes. Furthermore, it facilitates multiple error-compensative iterations of the finite-volume MPDATA and improved overall accuracy. The advancement combines straightforwardly with earlier developments, such as the nonoscillatory option, the infinite-gauge variant, and moving curvilinear meshes. A comprehensive description of the scheme is provided for a hybrid horizontally-unstructured vertically-structured computational mesh for efficient global atmospheric flow modelling. The proposed finite-volume MPDATA is verified using selected 3D global atmospheric benchmark simulations, representative of hydrostatic and non-hydrostatic flow regimes. Besides the added capabilities, the scheme retains fully the efficacy of established finite-volume MPDATA formulations.

  4. An unstructured-mesh finite-volume MPDATA for compressible atmospheric dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Kühnlein, Christian, E-mail: christian.kuehnlein@ecmwf.int; Smolarkiewicz, Piotr K., E-mail: piotr.smolarkiewicz@ecmwf.int

    2017-04-01

    An advancement of the unstructured-mesh finite-volume MPDATA (Multidimensional Positive Definite Advection Transport Algorithm) is presented that formulates the error-compensative pseudo-velocity of the scheme to rely only on face-normal advective fluxes to the dual cells, in contrast to the full vector employed in previous implementations. This is essentially achieved by expressing the temporal truncation error underlying the pseudo-velocity in a form consistent with the flux-divergence of the governing conservation law. The development is especially important for integrating fluid dynamics equations on non-rectilinear meshes whenever face-normal advective mass fluxes are employed for transport compatible with mass continuity—the latter being essential for flux-form schemes. In particular, the proposed formulation enables large-time-step semi-implicit finite-volume integration of the compressible Euler equations using MPDATA on arbitrary hybrid computational meshes. Furthermore, it facilitates multiple error-compensative iterations of the finite-volume MPDATA and improved overall accuracy. The advancement combines straightforwardly with earlier developments, such as the nonoscillatory option, the infinite-gauge variant, and moving curvilinear meshes. A comprehensive description of the scheme is provided for a hybrid horizontally-unstructured vertically-structured computational mesh for efficient global atmospheric flow modelling. The proposed finite-volume MPDATA is verified using selected 3D global atmospheric benchmark simulations, representative of hydrostatic and non-hydrostatic flow regimes. Besides the added capabilities, the scheme retains fully the efficacy of established finite-volume MPDATA formulations.

  5. Optimal dynamic detection of explosives

    Energy Technology Data Exchange (ETDEWEB)

    Moore, David Steven [Los Alamos National Laboratory; Mcgrane, Shawn D [Los Alamos National Laboratory; Greenfield, Margo T [Los Alamos National Laboratory; Scharff, R J [Los Alamos National Laboratory; Rabitz, Herschel A [PRINCETON UNIV; Roslund, J [PRINCETON UNIV

    2009-01-01

    The detection of explosives is a notoriously difficult problem, especially at stand-off distances, due to their (generally) low vapor pressure, environmental and matrix interferences, and packaging. We are exploring optimal dynamic detection to exploit the best capabilities of recent advances in laser technology and recent discoveries in optimal shaping of laser pulses for control of molecular processes to significantly enhance the standoff detection of explosives. The core of the ODD-Ex technique is the introduction of optimally shaped laser pulses to simultaneously enhance sensitivity of explosives signatures while reducing the influence of noise and the signals from background interferents in the field (increase selectivity). These goals are being addressed by operating in an optimal nonlinear fashion, typically with a single shaped laser pulse inherently containing within it coherently locked control and probe sub-pulses. With sufficient bandwidth, the technique is capable of intrinsically providing orthogonal broad spectral information for data fusion, all from a single optimal pulse.

  6. Proof testing of an explosion containment vessel

    Energy Technology Data Exchange (ETDEWEB)

    Esparza, E.D. [Esparza (Edward D.), San Antonio, TX (United States); Stacy, H.; Wackerle, J. [Los Alamos National Lab., NM (United States)

    1996-10-01

    A steel containment vessel was fabricated and proof tested for use by the Los Alamos National Laboratory at their M-9 facility. The HY-100 steel vessel was designed to provide total containment for high explosives tests up to 22 lb (10 kg) of TNT equivalent. The vessel was fabricated from an 11.5-ft diameter cylindrical shell, 1.5 in thick, and 2:1 elliptical ends, 2 in thick. Prior to delivery and acceptance, three types of tests were required for proof testing the vessel: a hydrostatic pressure test, air leak tests, and two full design charge explosion tests. The hydrostatic pressure test provided an initial static check on the capacity of the vessel and functioning of the strain instrumentation. The pneumatic air leak tests were performed before, in between, and after the explosion tests. After three smaller preliminary charge tests, the full design charge weight explosion tests demonstrated that no yielding occurred in the vessel at its rated capacity. The blast pressures generated by the explosions and the dynamic response of the vessel were measured and recorded with 33 strain channels, 4 blast pressure channels, 2 gas pressure channels, and 3 displacement channels. This paper presents an overview of the test program, a short summary of the methodology used to predict the design blast loads, a brief description of the transducer locations and measurement systems, some of the hydrostatic test strain and stress results, examples of the explosion pressure and dynamic strain data, and some comparisons of the measured data with the design loads and stresses on the vessel.

  7. Intermittent Explosive Disorder

    Science.gov (United States)

    ... explosive disorder involves repeated, sudden episodes of impulsive, aggressive, violent behavior or angry verbal outbursts in which you react grossly out of proportion to the situation. Road rage, domestic abuse, throwing or breaking objects, or other temper tantrums ...

  8. Preliminary results for explosion bonding of beryllium to copper

    International Nuclear Information System (INIS)

    Butler, D.J.; Dombrowski, D.E.

    1995-01-01

    This program was undertaken to determine if explosive bonding is a viable technique for joining beryllium to copper substrates. The effort was a cursory attempt at trying to solve some of the problems associated with explosive bonding beryllium and should not be considered a comprehensive research effort. There are two issues that this program addressed. Can beryllium be explosive bonded to copper substrates and can the bonding take place without shattering the beryllium? Thirteen different explosive bonding iterations were completed using various thicknesses of beryllium that were manufactured with three different techniques

  9. 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)

  10. Entropy Stable Staggered Grid Spectral Collocation for the Burgers' and Compressible Navier-Stokes Equations

    Science.gov (United States)

    Carpenter, Mark H.; Parsani, Matteo; Fisher, Travis C.; Nielsen, Eric J.

    2015-01-01

    Staggered grid, entropy stable discontinuous spectral collocation operators of any order are developed for Burgers' and the compressible Navier-Stokes equations on unstructured hexahedral elements. This generalization of previous entropy stable spectral collocation work [1, 2], extends the applicable set of points from tensor product, Legendre-Gauss-Lobatto (LGL) to a combination of tensor product Legendre-Gauss (LG) and LGL points. The new semi-discrete operators discretely conserve mass, momentum, energy and satisfy a mathematical entropy inequality for both Burgers' and the compressible Navier-Stokes equations in three spatial dimensions. They are valid for smooth as well as discontinuous flows. The staggered LG and conventional LGL point formulations are compared on several challenging test problems. The staggered LG operators are significantly more accurate, although more costly to implement. The LG and LGL operators exhibit similar robustness, as is demonstrated using test problems known to be problematic for operators that lack a nonlinearly stability proof for the compressible Navier-Stokes equations (e.g., discontinuous Galerkin, spectral difference, or flux reconstruction operators).

  11. Techniques of industrial radiology in military explosives

    International Nuclear Information System (INIS)

    Alves, L.E.G.

    1985-01-01

    The use of industrial radiology techniques id very important for military explosive fabrication. The cylindrical-ogive bodies made in forged metal have their interior fulfilled with high melted explosive and they must explode when they reach the target. The granades, as these bodies are called, are thrown by cannons and their interior are submitted to high pressures and accelerations which can cause a premature detonation, in most case, in interior of tube, in case of they have defects in explosive mass. The origins of defects, its localization and classification presenting the techniques used and disposable in Brazil are discussed. (M.C.K.) [pt

  12. Flux dependency of particulate/colloidal fouling in seawater reverse osmosis systems

    KAUST Repository

    Salinas Rodríguez, S. G.

    2012-01-01

    Fouling is the main operational problem in seawater reverse osmosis systems (SWRO). Particulate fouling is traditionally measured through the silt density index (SDI) and through the modified fouling index (MFI). In recent years, ultrafiltration membranes were used successfully at constant flux-MFI-UF-to measure particulate/colloidal fouling potential and tested in sea water applications. Furthermore, constant flux operation allows predicting the rate of fouling in RO systems. The objectives of this study are: (1) to measure the flux effect in MFI-UF with different membranes (100, 30 and 10 kDa) for raw seawater and pre-treated water before reverse osmosis in three different locations; (2) to study the particulate and colloidal fouling potential of seawater in reverse osmosis systems; (3) to project the increase in pressure due to cake resistance in reverse osmosis systems. In this research, flat ultrafiltration membranes (100, 50, 30 and 10 kDa) are used in a con- stant flux filtration mode to test and compare real seawaters from various locations (North and Mediterranean Sea) and from various full scale facilities including different pre-treatments (i.e., ultrafiltration and coagulation + dual media filtration). The operated fluxes range from 350 down to values close to real RO operation, 15l(m2h)-1. After each filtration test, the MFI-UF is calculated to assess the particulate fouling potential. The obtained results showed that: (1) the particulate and colloidal fouling potential is directly proportional to the applied flux during filtration. This proportionality is related to the compression of the cake deposit occurring at high flux values; (2) the higher the flux, the higher the required pressure, the less porous the cake and therefore the higher the specific cake resistance; (3) particulate and colloidal fouling potential of seawater is site specific and is influenced by pre-treatment. © 2012 Desalination Publications. All rights reserved.

  13. Action Replay of Powerful Stellar Explosion

    Science.gov (United States)

    2008-03-01

    Astronomers have made the best ever determination of the power of a supernova explosion that was visible from Earth long ago. By observing the remnant of a supernova and a light echo from the initial outburst, they have established the validity of a powerful new method for studying supernovas. Using data from NASA's Chandra X-ray Observatory, ESA's XMM-Newton Observatory, and the Gemini Observatory, two teams of researchers studied the supernova remnant and the supernova light echo that are located in the Large Magellanic Cloud (LMC), a small galaxy about 160,000 light years from Earth. They concluded that the supernova occurred about 400 years ago (in Earth’s time frame), and was unusually bright and energetic. X-ray Image of SNR 0509-67.5 X-ray Image of SNR 0509-67.5 This result is the first time two methods - X-ray observations of a supernova remnant and optical observations of the expanding light echoes from the explosion - have both been used to estimate the energy of a supernova explosion. Up until now, scientists had only made such an estimate using the light seen soon after a star exploded, or using remnants that are several hundred years old, but not from both. "People didn't have advanced telescopes to study supernovas when they went off hundreds of years ago," said Armin Rest of Harvard University, who led the light echo observations using Gemini. "But we've done the next best thing by looking around the site of the explosion and constructing an action replay of it." People Who Read This Also Read... Milky Way's Super-efficient Particle Accelerators Caught in The Act Oldest Known Objects Are Surprisingly Immature Discovery of Most Recent Supernova in Our Galaxy NASA Unveils Cosmic Images Book in Braille for Blind Readers In 2004, scientists used Chandra to determine that a supernova remnant, known as SNR 0509-67.5 in the LMC, was a so-called Type Ia supernova, caused by a white dwarf star in a binary system that reaches a critical mass and explodes. In

  14. System for detecting nuclear explosions

    International Nuclear Information System (INIS)

    Rawls, L.E.

    1978-01-01

    Apparatus for detecting underground nuclear explosions is described that is comprised of an antenna located in the dielectric substance of a deep waveguide in the earth and adapted to detect low frequency electromagnetic waves generated by a nuclear explosion, the deep waveguide comprising the high conductivity upper sedimentary layers of the earth, the dielectric basement rock, and a high conductivity layer of basement rock due to the increased temperature thereof at great depths, and means for receiving the electromagnetic waves detected by said antenna means

  15. Induced groundwater flux by increases in the aquifer's total stress.

    Science.gov (United States)

    Chang, Ching-Min; Yeh, Hund-Der

    2015-01-01

    Fluid-filled granular soils experience changes in total stress because of earth and oceanic tides, earthquakes, erosion, sedimentation, and changes in atmospheric pressure. The pore volume may deform in response to the changes in stress and this may lead to changes in pore fluid pressure. The transient fluid flow can therefore be induced by the gradient in excess pressure in a fluid-saturated porous medium. This work demonstrates the use of stochastic methodology in prediction of induced one-dimensional field-scale groundwater flow through a heterogeneous aquifer. A closed-form of mean groundwater flux is developed to quantify the induced field-scale mean behavior of groundwater flow and analyze the impacts of the spatial correlation length scale of log hydraulic conductivity and the pore compressibility. The findings provided here could be useful for the rational planning and management of groundwater resources in aquifers that contain lenses with large vertical aquifer matrix compressibility values. © 2014, National Ground Water Association.

  16. Excessive chest compression rate is associated with insufficient compression depth in prehospital cardiac arrest.

    Science.gov (United States)

    Monsieurs, Koenraad G; De Regge, Melissa; Vansteelandt, Kristof; De Smet, Jeroen; Annaert, Emmanuel; Lemoyne, Sabine; Kalmar, Alain F; Calle, Paul A

    2012-11-01

    BACKGROUND AND GOAL OF STUDY: The relationship between chest compression rate and compression depth is unknown. In order to characterise this relationship, we performed an observational study in prehospital cardiac arrest patients. We hypothesised that faster compressions are associated with decreased depth. In patients undergoing prehospital cardiopulmonary resuscitation by health care professionals, chest compression rate and depth were recorded using an accelerometer (E-series monitor-defibrillator, Zoll, U.S.A.). Compression depth was compared for rates 120/min. A difference in compression depth ≥0.5 cm was considered clinically significant. Mixed models with repeated measurements of chest compression depth and rate (level 1) nested within patients (level 2) were used with compression rate as a continuous and as a categorical predictor of depth. Results are reported as means and standard error (SE). One hundred and thirty-three consecutive patients were analysed (213,409 compressions). Of all compressions 2% were 120/min, 36% were 5 cm. In 77 out of 133 (58%) patients a statistically significant lower depth was observed for rates >120/min compared to rates 80-120/min, in 40 out of 133 (30%) this difference was also clinically significant. The mixed models predicted that the deepest compression (4.5 cm) occurred at a rate of 86/min, with progressively lower compression depths at higher rates. Rates >145/min would result in a depth compression depth for rates 80-120/min was on average 4.5 cm (SE 0.06) compared to 4.1 cm (SE 0.06) for compressions >120/min (mean difference 0.4 cm, Pcompression rates and lower compression depths. Avoiding excessive compression rates may lead to more compressions of sufficient depth. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

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

    OpenAIRE

    N Matsuo; M Otuka; H Hamasima; K Hokamoto; S Itoh

    2016-01-01

    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 ...

  18. Early light curves for Type Ia supernova explosion models

    Science.gov (United States)

    Noebauer, U. M.; Kromer, M.; Taubenberger, S.; Baklanov, P.; Blinnikov, S.; Sorokina, E.; Hillebrandt, W.

    2017-12-01

    Upcoming high-cadence transient survey programmes will produce a wealth of observational data for Type Ia supernovae. These data sets will contain numerous events detected very early in their evolution, shortly after explosion. Here, we present synthetic light curves, calculated with the radiation hydrodynamical approach STELLA for a number of different explosion models, specifically focusing on these first few days after explosion. We show that overall the early light curve evolution is similar for most of the investigated models. Characteristic imprints are induced by radioactive material located close to the surface. However, these are very similar to the signatures expected from ejecta-CSM or ejecta-companion interaction. Apart from the pure deflagration explosion models, none of our synthetic light curves exhibit the commonly assumed power-law rise. We demonstrate that this can lead to substantial errors in the determination of the time of explosion. In summary, we illustrate with our calculations that even with very early data an identification of specific explosion scenarios is challenging, if only photometric observations are available.

  19. Energy and impacts of pressure vessel explosions

    International Nuclear Information System (INIS)

    Kurttila, H.

    1999-01-01

    In this paper the explosion energy is considered to be same as the energy of pressure vessel discharge. This is the maximum energy which can be obtained from the process. The energy can be used or it can cause the violence of an explosion accident. (orig.)

  20. Detection Dynamics Of Nitrogen Based Explosive Quantities In Selected Cylindrical Containers

    Directory of Open Access Journals (Sweden)

    Ngusha Tavershima Almighty

    2017-12-01

    Full Text Available An experimental set up for examining the variation of detection intensity with explosive quantity has been studied. Containers made from ceramic carbon steel wood and HDPE were filled with explosive masses ranging from 10 kg to 500 kg and irradiated by a 14.1 MeV point isotropic neutron source. The resulting gamma photons were analyzed for their C N and O composition and the sum computed to yield a quantity known as the material quotient MQ. Examination of MQ values indicates an initial increase in detection intensity with increasing explosive quantity. Saturation is however reached at an explosive quantity of about 25kg where detection intensity reduces with further increase in explosive quantity. Effects of variation in explosive quantity appeared to be more pronounced for explosives contained in HDPE and wooden containers and least pronounced for those in steel containers. Source-detector configuration was identified as a major factor affecting effective detection of large masses of explosives.

  1. Physics of phenomena in the zone close to an underground nuclear explosion; Physique des phenomenes en zone proche des explosions nucleaires souterraines

    Energy Technology Data Exchange (ETDEWEB)

    Maury, J.; Levret, C. [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes

    1969-07-01

    After a description of the phenomenology of underground explosions, the basic laws governing the propagation in the ground of the energy produced by the explosion are given. The reports considers hydrodynamics, the mechanics of solids, the equations of state for solids and gases in the case of very high and medium pressures, and the dynamical strength of solids. These various elements make it possible to draw up a system of equations which define completely the changes with time of the shock-wave produced in the ground by the explosion. (authors) [French] Apres une description de la phenomenologie des explosions souterraines, on expose les lois fondamentales regissant la propagation dans le sol de l'energie degagee par l'explosion. L'expose comprend des developpements sur l'hydrodynamique, la mecanique des solides, les equations d'etat des solides et des gaz, aux tres fortes et moyennes pressions, et sur la resistance dynamique des solides. Ces differents elements permettent d'ecrire un systeme d'equations qui definissent completement l'evolution dans le temps de l'onde de choc emise dans le sol par l'explosion. (auteurs)

  2. Episodic Jurassic to Lower Cretaceous intraplate compression in Central Patagonia during Gondwana breakup

    Science.gov (United States)

    Navarrete, César; Gianni, Guido; Echaurren, Andrés; Kingler, Federico Lince; Folguera, Andrés

    2016-12-01

    From Lower Jurassic to Lower Cretaceous, several intraplate compression events affected discrete sectors of Central Patagonia, under a general context of crustal extension associated with Gondwana breakup. This was demonstrated by means of 2D and 3D seismic and borehole data, which show partial inversion of Lower and Middle Jurassic extensional structures of the Chubut and Cañadón Asfalto basins, during the earliest stages of breakup. A comparison with surrounding areas in Patagonia, where similar Jurassic intraplate compression was described, allowed the discrimination of three discrete pulses of subtle compression (C1: ∼188-185 Ma; C2: ∼170-163; C3: ∼157-136? Ma). Interestingly, episodic intraplate compressional events are closely followed by high flux magmatic events linked to the westward expansion of the Karoo-Ferrar thermal anomaly, which impacted on the lithosphere of southwest Gondwana in Lower Jurassic. In addition, we determined the approximate direction of the main compressive strain (σ1) compatible with other Jurassic intraplate belts of South America. These observations led us to propose a linkage between a thermo mechanically weakened continental crust due to LIPs activity, changes in plate motions and ridge-push forces generated by the opening of the Weddell Sea, in order to explain intraplate shortening, interrupted while Karoo LIPs magmatic invigoration took place.

  3. Peaceful nuclear explosions

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1975-07-01

    Article V of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) specifies that the potential benefits of peaceful applications of nuclear explosions be made available to non-nuclear weapon states party to the Treaty 'under appropriate international observation and through appropriate international procedures'. The International Atomic Energy Agency's responsibility and technical competence in this respect have been recognized by its Board of Governors, the Agency's General Conference and the United Nations' General Assembly. Since 1968 when the United Nations Conference of Non-Nuclear Weapon States also recommended that the Agency initiate the necessary studies in the peaceful nuclear explosions (PNE) field, the Agency has taken the following steps: 1. The exchange of scientific and technical information has been facilitated by circulating information on the status of the technology and through the Agency's International Nuclear Information System. A bibliography of PNE-related literature was published in 1970. 2. In 1972, guidelines for 'the international observation of PNE under the provisions of NPT and analogous provisions in other international agreements' were developed and approved by the Board of Governors. These guidelines defined the basic purpose of international observation as being to verify that in the course of conducting a PNE project the intent and letter of Articles I and II of the NPT are not violated. 3. In 1974, an advisory group developed 'Procedures for the Agency to Use in Responding to Requests for PNE-Related Services'. These procedures have also been approved by the Board of Governors. 4. The Agency has convened a series of technical meetings which reviewed the 'state-of-the- art'. These meetings were convened in 1970, 1971, 1972 and in January 1975. The Fourth Technical Committee was held in Vienna from 20-24 January 1975 under the chairmanship of Dr. Allen Wilson of Australia with Experts from: Australia, France, Federal

  4. Raman hyperspectral imaging in conjunction with independent component analysis as a forensic tool for explosive analysis: The case of an ATM explosion.

    Science.gov (United States)

    Almeida, Mariana Ramos; Logrado, Lucio Paulo Lima; Zacca, Jorge Jardim; Correa, Deleon Nascimento; Poppi, Ronei Jesus

    2017-11-01

    In this work, Raman hyperspectral imaging, in conjunction with independent component analysis, was employed as an analytical methodology to detect an ammonium nitrate fuel oil (ANFO) explosive in banknotes after an ATM explosion experiment. The proposed methodology allows for the identification of the ANFO explosive without sample preparation or destroying the sample, at quantities as small as 70μgcm -2 . The explosive was identified following ICA data decomposition by the characteristic nitrate band at 1044cm -1 . The use of Raman hyperspectral imaging and independent component analysis shows great potential for identifying forensic samples by providing chemical and spatial information. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Excavation research with chemical explosives

    Energy Technology Data Exchange (ETDEWEB)

    Vandenberg, William E; Day, Walter C [U.S. Army Engineer Nuclear Cratering Group, Lawrence Radiation Laboratory, Livermore, CA (United States)

    1970-05-01

    The US Army Engineer Nuclear Cratering Group (NCG) is located at the Lawrence Radiation Laboratory in Livermore, California. NCG was established in 1962 and assigned responsibility for technical program direction of the Corps of Engineers Nuclear Excavation Research Program. The major part of the experimental program has been the execution of chemical explosive excavation experiments. In the past these experiments were preliminary to planned nuclear excavation experiments. The experience gained and technology developed in accomplishing these experiments has led to an expansion of NCG's research mission. The overall research and development mission now includes the development of chemical explosive excavation technology to enable the Corps of Engineers to more economically accomplish Civil Works Construction projects of intermediate size. The current and future chemical explosive excavation experiments conducted by NCG will be planned so as to provide data that can be used in the development of both chemical and nuclear excavation technology. In addition, whenever possible, the experiments will be conducted at the specific sites of authorized Civil Works Construction Projects and will be designed to provide a useful portion of the engineering structures planned in that project. Currently, the emphasis in the chemical explosive excavation program is on the development of design techniques for producing specific crater geometries in a variety of media. Preliminary results of two such experiments are described in this paper; Project Pre-GONDOLA III, Phase III, Reservoir Connection Experiment; and a Safety Calibration Series for Project TUGBOAT, a small boat harbor excavation experiment.

  6. Excavation research with chemical explosives

    International Nuclear Information System (INIS)

    Vandenberg, William E.; Day, Walter C.

    1970-01-01

    The US Army Engineer Nuclear Cratering Group (NCG) is located at the Lawrence Radiation Laboratory in Livermore, California. NCG was established in 1962 and assigned responsibility for technical program direction of the Corps of Engineers Nuclear Excavation Research Program. The major part of the experimental program has been the execution of chemical explosive excavation experiments. In the past these experiments were preliminary to planned nuclear excavation experiments. The experience gained and technology developed in accomplishing these experiments has led to an expansion of NCG's research mission. The overall research and development mission now includes the development of chemical explosive excavation technology to enable the Corps of Engineers to more economically accomplish Civil Works Construction projects of intermediate size. The current and future chemical explosive excavation experiments conducted by NCG will be planned so as to provide data that can be used in the development of both chemical and nuclear excavation technology. In addition, whenever possible, the experiments will be conducted at the specific sites of authorized Civil Works Construction Projects and will be designed to provide a useful portion of the engineering structures planned in that project. Currently, the emphasis in the chemical explosive excavation program is on the development of design techniques for producing specific crater geometries in a variety of media. Preliminary results of two such experiments are described in this paper; Project Pre-GONDOLA III, Phase III, Reservoir Connection Experiment; and a Safety Calibration Series for Project TUGBOAT, a small boat harbor excavation experiment

  7. Coulomb explosion of “hot spot”

    Energy Technology Data Exchange (ETDEWEB)

    Oreshkin, V. I., E-mail: oreshkin@ovpe.hcei.tsc.ru [Institute of High Current Electrons, SB, RAS, Tomsk (Russian Federation); Tomsk Polytechnic University, Tomsk (Russian Federation); Oreshkin, E. V. [P. N. Lebedev Physical Institute, RAS, Moscow (Russian Federation); Chaikovsky, S. A. [Institute of High Current Electrons, SB, RAS, Tomsk (Russian Federation); P. N. Lebedev Physical Institute, RAS, Moscow (Russian Federation); Institute of Electrophysics, UD, RAS, Ekaterinburg (Russian Federation); Artyomov, A. P. [Institute of High Current Electrons, SB, RAS, Tomsk (Russian Federation)

    2016-09-15

    The study presented in this paper has shown that the generation of hard x rays and high-energy ions, which are detected in pinch implosion experiments, may be associated with the Coulomb explosion of the hot spot that is formed due to the outflow of the material from the pinch cross point. During the process of material outflow, the temperature of the hot spot plasma increases, and conditions arise for the plasma electrons to become continuously accelerated. The runaway of electrons from the hot spot region results in the buildup of positive space charge in this region followed by a Coulomb explosion. The conditions for the hot spot plasma electrons to become continuously accelerated have been revealed, and the estimates have been obtained for the kinetic energy of the ions generated by the Coulomb explosion.

  8. Coulomb explosion of “hot spot”

    International Nuclear Information System (INIS)

    Oreshkin, V. I.; Oreshkin, E. V.; Chaikovsky, S. A.; Artyomov, A. P.

    2016-01-01

    The study presented in this paper has shown that the generation of hard x rays and high-energy ions, which are detected in pinch implosion experiments, may be associated with the Coulomb explosion of the hot spot that is formed due to the outflow of the material from the pinch cross point. During the process of material outflow, the temperature of the hot spot plasma increases, and conditions arise for the plasma electrons to become continuously accelerated. The runaway of electrons from the hot spot region results in the buildup of positive space charge in this region followed by a Coulomb explosion. The conditions for the hot spot plasma electrons to become continuously accelerated have been revealed, and the estimates have been obtained for the kinetic energy of the ions generated by the Coulomb explosion.

  9. Trend analysis of explosion events at overseas nuclear power plants

    International Nuclear Information System (INIS)

    Shimada, Hiroki

    2008-01-01

    We surveyed failures caused by disasters (e.g., severe storms, heavy rainfall, earthquakes, explosions and fires) which occurred during the 13 years from 1995 to 2007 at overseas nuclear power plants (NPPs) from the nuclear information database of the Institute of Nuclear Safety System. Incorporated (INSS). The results revealed that explosions were the second most frequent type of failure after fires. We conducted a trend analysis on such explosion events. The analysis by equipment, cause, and effect on the plant showed that the explosions occurred mainly at electrical facilities, and thus it is essential to manage the maintenance of electrical facilities for preventing explosions. In addition, it was shown that explosions at transformers and batteries, which have never occurred at Japan's NPPs, accounted for as much as 55% of all explosions. The fact infers that this difference is attributable to the difference in maintenance methods of transformers (condition based maintenance adopted by NPPs) and workforce organization of batteries (inspections performed by utilities' own maintenance workers at NPPs). (author)

  10. A Finite Element Method for Simulation of Compressible Cavitating Flows

    Science.gov (United States)

    Shams, Ehsan; Yang, Fan; Zhang, Yu; Sahni, Onkar; Shephard, Mark; Oberai, Assad

    2016-11-01

    This work focuses on a novel approach for finite element simulations of multi-phase flows which involve evolving interface with phase change. Modeling problems, such as cavitation, requires addressing multiple challenges, including compressibility of the vapor phase, interface physics caused by mass, momentum and energy fluxes. We have developed a mathematically consistent and robust computational approach to address these problems. We use stabilized finite element methods on unstructured meshes to solve for the compressible Navier-Stokes equations. Arbitrary Lagrangian-Eulerian formulation is used to handle the interface motions. Our method uses a mesh adaptation strategy to preserve the quality of the volumetric mesh, while the interface mesh moves along with the interface. The interface jump conditions are accurately represented using a discontinuous Galerkin method on the conservation laws. Condensation and evaporation rates at the interface are thermodynamically modeled to determine the interface velocity. We will present initial results on bubble cavitation the behavior of an attached cavitation zone in a separated boundary layer. We acknowledge the support from Army Research Office (ARO) under ARO Grant W911NF-14-1-0301.

  11. Desenvolvimento de comprimidos de AAS 500 mg: influência do Amido 1500® na compressão direta Development of AAS 500 mg tablets influenced by direct compression (CD process

    Directory of Open Access Journals (Sweden)

    Osvaldo Albuquerque Cavalcanti

    2002-04-01

    Full Text Available O experimento teve por objetivo demonstrar a viabilidade tecnológica do desenvolvimento de comprimidos de AAS 500 mg (Ácido Acetil Salicílico, empregando processo de compressão direta (CD. O Amido 1500® foi usado como excipiente no desenvolvimento das formulações, visando investigar suas propriedades de compressibilidade, desintegração, agregação e lubrificação. Usando metodologias previstas em Farmacopéias, foram realizados ensaios tecnológicos e físico-químicos. Os resultados evidenciaram que a mistura dos pós apresentou características de fluxo e compressibilidade adequadas ao rol de excipientes para compressão direta disponíveis no mercado. A presença do Amido 1500® também interferiu no tempo de desintegração. Dentre as formulações propostas neste trabalho, a fórmula contendo 6,35% de Amido 1500® foi eleita a mais adequada por apresentar maior proximidade em relação aos produtos disponíveis no mercado brasileiroThe present work aims to show the technologic viability in the development of AAS 500 mg tablets using direct compression (CD process. We employed Starch 1500® as excipient to develop the formulations, trying to investigate its compression, disintegration, aggregation and lubrication properties. Technologic, physical and chemical essays were performed using methodologies anticipated in pharmacology. Results demonstrated that the powder mix showed characteristics of free flux and good compression qualities very important for the excipients of direct compression in the market. Starch 1500® interfered in the disintegration time. The formulation with 6,35% of Starch 1500® proposed in this work obtained a highest proximity between the products in the Brazilian market

  12. 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.

  13. Modeling Hot-Spot Contributions in Shocked High Explosives at the Mesoscale

    Energy Technology Data Exchange (ETDEWEB)

    Harrier, Danielle [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-08-12

    When looking at performance of high explosives, the defects within the explosive become very important. Plastic bonded explosives, or PBXs, contain voids of air and bonder between the particles of explosive material that aid in the ignition of the explosive. These voids collapse in high pressure shock conditions, which leads to the formation of hot spots. Hot spots are localized high temperature and high pressure regions that cause significant changes in the way the explosive material detonates. Previously hot spots have been overlooked with modeling, but now scientists are realizing their importance and new modeling systems that can accurately model hot spots are underway.

  14. A row-charge nuclear cratering explosion in alluvial rocks

    International Nuclear Information System (INIS)

    Kireev, V.V.; Kedrovskij, O.L.; Valentinov, Yu.A.; Myasnikov, K.V.; Nikiforov, G.A.; Prozorov, L.B.; Potapov, V.K.

    1975-01-01

    A brief description is given of the first row-charge nuclear cratering explosion in alluvial rocks carried out on the route of the Pechora-Kolva canal. The authors explain the purposes of the explosion, describe the geological conditions, indicate the emplacement parameters and yields of the charges, present data on the dynamics of development of the explosion and report on its seismic effects. The parameters of the resulting trench cut and the characteristics of the rock ejecta are also given. The possibility of using nuclear explosions for hydrotechnological projects requiring large excavations in a thick stratum of weak water-bearing rocks is considered

  15. Computer code TRANS-ACE predicting for fire and explosion accidents in nuclear fuel reprocessing plants

    International Nuclear Information System (INIS)

    Abe, Hitoshi; Nishio; Gunji; Naito, Yoshitaka

    1993-11-01

    The accident analysis code TRANS-ACE was developed to evaluate the safety of a ventilation system in a reprocessing plant in the event of fire and explosion accidents. TRANS-ACE can evaluate not only the integrity of a ventilation system containing HEPA filters but also the source term of radioactive materials for release out of a plant. It calculates the temperature, pressure, flow rate, transport of combustion materials and confinement of radioactive materials in the network of a ventilation system that might experience a fire or explosion accident. TRANS-ACE is based on the one-dimensional compressible thermo-fluid analysis code EVENT developed by Los Alamos National Laboratory (LANL). Calculational functions are added for the radioactive source term, heat transfer and radiation to cell and duct walls and HEPA filter integrity. For the second edition in the report, TRANS-ACE has been improved incorporating functions for the initial steady-state calculation to determine the flow rates, pressure drops and temperature in the network before an accident mode analysis. It is also improved to include flow resistance calculations of the filters and blowers in the network and to have an easy to use code by simplifying the input formats. This report is to prepare an explanation of the mathematical model for TRANS-ACE code and to be the user's manual. (author)

  16. CHARGED PARTICLE MOTION IN AN EXPLOSIVELY GENERATED IONIZING SHOCK

    International Nuclear Information System (INIS)

    Boswell, Christopher J.; O'Connor, Patrick D.

    2009-01-01

    Different aspects of the plasma generated in a gas contained in a tube due to detonation of a small explosive charge located at one end of the tube are presented. The motion of the charged particles within the plasma is monitored using Rogowski coils. Using time-resolved emission spectroscopy the temperature and species in the detonation products and compressed gas behind the shock wave are recorded. From the spectral lines of the emission profiles the temperatures and electron density were evaluated to be in the vicinity of 7,000 K and 5x10 22 m -3 . An ultra fast wave traveling down the guide tube ahead of the hydrodynamic shock and causing any charged particles there to move fast enough to be detected by the Rogowski coils was recorded. From the measurements the phase velocity of the wave was calculated at 525 km/s when krypton filled the tube, and 1300 km/s in the case of argon. The temperature and density measurements are consistent with the data reported in the literature for similar tests. The electrostatic pulse measurements are a new phenomena not previously observed.

  17. The impact of chest compression rates on quality of chest compressions : a manikin study

    OpenAIRE

    Field, Richard A.; Soar, Jasmeet; Davies, Robin P.; Akhtar, Naheed; Perkins, Gavin D.

    2012-01-01

    Purpose\\ud Chest compressions are often performed at a variable rate during cardiopulmonary resuscitation (CPR). The effect of compression rate on other chest compression quality variables (compression depth, duty-cycle, leaning, performance decay over time) is unknown. This randomised controlled cross-over manikin study examined the effect of different compression rates on the other chest compression quality variables.\\ud Methods\\ud Twenty healthcare professionals performed two minutes of co...

  18. Radioactive and Other Effects of Nuclear Explosion

    International Nuclear Information System (INIS)

    Ilijas, B.; Cizmek, A.; Prah, M.; Medakovic, S.

    2008-01-01

    As a result of long lasting efforts of international community to definitely ban all test nuclear explosions, the Comprehensive Nuclear-Test-Ban Treaty (CTBT) was opened for signature in New York on 24 September 1996, when it was signed by 71 states, including Croatia. The State Office for Nuclear Safety (SONS) which, as an independent state regulatory authority has a responsibility for activities relating to nuclear safety, including the national authority over this Treaty, is actively engaged in CTBTO activities. The nuclear explosion causes a lot of effects (blast, thermal, radioactive, electromagnetic) which differs a lot in its nature, reach, lasting and other. The longest lasting aftermath is from the radioactive effects that cause a radioactive fallout and a lot of radioactive elements in the environment, created by the influence of a primary beam of radiation. Fission and fusion are the main source of radionuclide created by the nuclear explosion, and the longest lasting aftermaths are by the fission products, namely their offspring in natural disintegration chains. This can make contaminated areas inappropriate for life for very long periods. Even in the case of underground nuclear explosion (when underground cavity is formed with no effects on the surface), a leakage of radioactive gases through cracks is possible. A number of radionuclide is created by the neutron activation of elements naturally present in an environment, because a very strong neutron radiation appears in the moment of nuclear explosion. The abundance of particular radionuclide is a very much dependent of a place of performing nuclear explosion and a composition of soil or water in the vicinity.(author)

  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. The Railgun and Its Power Source,

    Science.gov (United States)

    1987-06-01

    inductor 66 3.1.3 The ANU homopolar generator power source 67 3.1.4 Features of an ideal power source 69 3.1.5 Desirable power source pulse energy...3.3.2 Homopolar generators 75 3.3.3 Ordinary large alternators 77 3.3.4 The compulsator 77 3.4 Explosive magnetic flux compression 80 3.5 Minimum mass of...discharge of lead-acid batteries 99 4.4.4 Design and performance of a high rate lead-acid cell 101 4.5 Motor -generator instead of batteries 103 4.5.1

  1. The Los Alamos foil implosion project

    International Nuclear Information System (INIS)

    Brownell, J.; Parker, J.; Bartsch, R.; Benage, J.; Bowers, R.; Cochrane, J.; Forman, P.; Goforth, J.; Greene, A.; Kruse, H.

    1993-01-01

    The goal of the Los Alamos foil implosion project is to produce an intense (>100 TW), multi-megajoule, laboratory soft x-ray source for material studies and fusion experiments. The concept involves the implosion of annular, current-carrying, cylindrical metallic plasmas via their self-magnetic forces. The project features inductive storage systems using both capacitor banks and high explosive-driven flux compression generators as prime energy sources. Fast opening switches are employed to shorten the electrical pulses. The program will be described and activities to date will be summarized

  2. Radiation diagnostics in extremely harsh environments

    International Nuclear Information System (INIS)

    Dona, H.; Lee, P.H.Y.; Williams, A.H.; McGurn, J.L.; Veeser, L.R.

    1986-01-01

    Some recent Trailmaster experiments have required to use of rather delicate radiation diagnostics in hostile environments. We have developed instrumentation for use high-explosive magnetic flux compression generators and near the noisy environment of high energy capacitor banks. These include some rather unique ''fly-away'' designs for x-ray imaging and spectroscopy, and other optical techniques for plasma temperature and field measurements. We will show some representative data and will also discuss an on-going program for the determination of magnetic field via atomic spectral line splitting and/or broadening

  3. A Distributed Lag Autoregressive Model of Geostationary Relativistic Electron Fluxes: Comparing the Influences of Waves, Seed and Source Electrons, and Solar Wind Inputs

    Science.gov (United States)

    Simms, Laura; Engebretson, Mark; Clilverd, Mark; Rodger, Craig; Lessard, Marc; Gjerloev, Jesper; Reeves, Geoffrey

    2018-05-01

    Relativistic electron flux at geosynchronous orbit depends on enhancement and loss processes driven by ultralow frequency (ULF) Pc5, chorus, and electromagnetic ion cyclotron (EMIC) waves, seed electron flux, magnetosphere compression, the "Dst effect," and substorms, while solar wind inputs such as velocity, number density, and interplanetary magnetic field Bz drive these factors and thus correlate with flux. Distributed lag regression models show the time delay of highest influence of these factors on log10 high-energy electron flux (0.7-7.8 MeV, Los Alamos National Laboratory satellites). Multiple regression with an autoregressive term (flux persistence) allows direct comparison of the magnitude of each effect while controlling other correlated parameters. Flux enhancements due to ULF Pc5 and chorus waves are of equal importance. The direct effect of substorms on high-energy electron flux is strong, possibly due to injection of high-energy electrons by the substorms themselves. Loss due to electromagnetic ion cyclotron waves is less influential. Southward Bz shows only moderate influence when correlated processes are accounted for. Adding covariate compression effects (pressure and interplanetary magnetic field magnitude) allows wave-driven enhancements to be more clearly seen. Seed electrons (270 keV) are most influential at lower relativistic energies, showing that such a population must be available for acceleration. However, they are not accelerated directly to the highest energies. Source electrons (31.7 keV) show no direct influence when other factors are controlled. Their action appears to be indirect via the chorus waves they generate. Determination of specific effects of each parameter when studied in combination will be more helpful in furthering modeling work than studying them individually.

  4. 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

    The goal of this project has been to develop a quantitative predictive capability for explosion-generated Lg phases with a sound and unambiguous physical basis. The research program consisted of a theoretical investigation of explosion-generated Lg combined with an observational study. The specific question addressed by this research program is how the Lg phase is generated by underground nuclear explosions. This question is fundamental to how Lg phases are interpreted for use in explosion yield estimation and earthquake/explosion discrimination. To constrain modeling, we have extensively reviewed the existing literature and complemented that work with an examination of several explosion data sets, most notably: (1) Degelen Mountain explosions recorded between 7 and 57 km, with corresponding recordings at Borovoye, at approximately 650 km; (2) recordings from Russian deep seismic sounding experiments; (3) NTS explosion sources including the NPE and nuclear tests covering a range of source depths and media properties. A simple point explosion in an infinite medium generates no shear waves, so the Lg phase is generated entirely by non-spherical components of the source and conversions through reflections and scattering. We find that the most important contributors to the Lg phase are: (1) P to S conversion at the free surface and other near source interfaces, (2) S waves generated directly by a realistically distributed explosion source including nonlinear effects due to the free surface and gravity, and (3) Rg scattering to Lg. Additional effects that contribute significantly to Lg are scattering of converted S phases that traps more of the converted P-to-S in the crust, and randomization of the components of Lg. The pS phase from a spherically symmetric explosion source in media with P-wave velocity less than upper mantle S-wave velocity is trapped in the crust and can explain the observed radial and vertical Lg. The free surface pS converted phase from the same

  5. Impact initiation of explosives and propellants via statistical crack mechanics

    Science.gov (United States)

    Dienes, J. K.; Zuo, Q. H.; Kershner, J. D.

    2006-06-01

    A statistical approach has been developed for modeling the dynamic response of brittle materials by superimposing the effects of a myriad of microcracks, including opening, shear, growth and coalescence, taking as a starting point the well-established theory of penny-shaped cracks. This paper discusses the general approach, but in particular an application to the sensitivity of explosives and propellants, which often contain brittle constituents. We examine the hypothesis that the intense heating by frictional sliding between the faces of a closed crack during unstable growth can form a hot spot, causing localized melting, ignition, and fast burn of the reactive material adjacent to the crack. Opening and growth of a closed crack due to the pressure of burned gases inside the crack and interactions of adjacent cracks can lead to violent reaction, with detonation as a possible consequence. This approach was used to model a multiple-shock experiment by Mulford et al. [1993. Initiation of preshocked high explosives PBX-9404, PBX-9502, PBX-9501, monitored with in-material magnetic gauging. In: Proceedings of the 10th International Detonation Symposium, pp. 459-467] involving initiation and subsequent quenching of chemical reactions in a slab of PBX 9501 impacted by a two-material flyer plate. We examine the effects of crack orientation and temperature dependence of viscosity of the melt on the response. Numerical results confirm our theoretical finding [Zuo, Q.H., Dienes, J.K., 2005. On the stability of penny-shaped cracks with friction: the five types of brittle behavior. Int. J. Solids Struct. 42, 1309-1326] that crack orientation has a significant effect on brittle behavior, especially under compressive loading where interfacial friction plays an important role. With a reasonable choice of crack orientation and a temperature-dependent viscosity obtained from molecular dynamics calculations, the calculated particle velocities compare well with those measured using

  6. 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).

  7. Weapons Experiments Division Explosives Operations Overview

    Energy Technology Data Exchange (ETDEWEB)

    Laintz, Kenneth E. [Los Alamos National Laboratory

    2012-06-19

    Presentation covers WX Division programmatic operations with a focus on JOWOG-9 interests. A brief look at DARHT is followed by a high level overview of explosives research activities currently being conducted within in the experimental groups of WX-Division. Presentation covers more emphasis of activities and facilities at TA-9 as these efforts have been more traditionally aligned with ongoing collaborative explosive exchanges covered under JOWOG-9.

  8. Evaluation of the Thermochemical Code - CHEETAH 2.0 for Modelling Explosives Performance

    National Research Council Canada - National Science Library

    Lu, Jing

    2001-01-01

    The Lawrence Livermore National Laboratory CHEETAH 2.0 program has been used to analyse a number of conventional ideal explosive ingredients, ideal explosive compositions, non-ideal explosive compositions, and new and proposed explosives...

  9. 36 CFR 331.5 - Explosives and fireworks.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Explosives and fireworks. 331... CONSERVATION AREA, KENTUCKY AND INDIANA § 331.5 Explosives and fireworks. Unless otherwise authorized in writing by the District Engineer. (a) The possession or use of fireworks is prohibited. (b) The possession...

  10. Recent Advances in Understanding Large Scale Vapour Explosions

    International Nuclear Information System (INIS)

    Board, S.J.; Hall, R.W.

    1976-01-01

    In foundries, violent explosions occur occasionally when molten metal comes into contact with water. If similar explosions can occur with other materials, hazardous situations may arise for example in LNG marine transportation accidents, or in liquid cooled reactor incidents when molten UO 2 contacts water or sodium coolant. Over the last 10 years a large body of experimental data has been obtained on the behaviour of small quantities of hot material in contact with a vaporisable coolant. Such experiments generally give low energy yields, despite producing fine fragmentation of the molten material. These events have been interpreted in terms of a wide range of phenomena such as violent boiling, liquid entrainment, bubble collapse, superheat, surface cracking and many others. Many of these studies have been aimed at understanding the small scale behaviour of the particular materials of interest. However, understanding the nature of the energetic events which were the original cause for concern may also be necessary to give confidence that violent events cannot occur for these materials in large scale situations. More recently, there has been a trend towards larger experiments and some of these have produced explosions of moderately high efficiency. Although occurrence of such large scale explosions can depend rather critically on initial conditions in a way which is not fully understood, there are signs that the interpretation of these events may be more straightforward than that of the single drop experiments. In the last two years several theoretical models for large scale explosions have appeared which attempt a self contained explanation of at least some stages of such high yield events: these have as their common feature a description of how a propagating breakdown of an initially quasi-stable distribution of materials is induced by the pressure and flow field caused by the energy release in adjacent regions. These models have led to the idea that for a full

  11. The explosion-proof container, satisfying the IAEA norms on safety

    International Nuclear Information System (INIS)

    Syrunin, M.A.; Fedorenko, A.G.; Ivanov, A.G.; Abakumov, A.I.; Nizovtsev, P.N.; Loginov, P.G.; Smolyakov, A.A.; Solov'ev, V.P.

    1998-01-01

    Safety of radioactive materials (RM) transportation is under strict control of the international norms of IAEA, aimed to ensure non-proliferation of hazardous materials in the environments. At the same time the nuclear countries use much more dangerous transportations of two types of hazardous materials. Probability of emergency explosion of high explosives (HE) during transportation and storage of such constructions is not equal to zero. HE explosion can be caused by: 1)excess of mechanical effects, allowable by the norms, on an explosive 2)lightening or fire 3)terrorist attack 4)radio controlled or time controlled mechanism in case of the terrorist device. It is obvious that an accident with explosion HE element of the nuclear weapon in an usual container, which meets the IAEA norms, but is not explosion-proof, will result in its destruction, RM dispersal, and inadmissible pollution of the environments. Therefore, it is urgent need for development of the container, which is able to withstand explosion of HE, placed in it, and to confine released RM inside of it. The experimental prototype of the load-bearing shell of the explosion-proof container (EC) can be the successfully tested spherical steel - glass plastic shell, having high-strength throats and lids. Having weight of 45-50 kg it is able to withstand internal explosion with energy more than 1.4 kg of the TNT equivalent. To preserve the explosion-proofness property in the abnormal environments during transportation, the explosion-proof container should be placed in the protective supporting transport device or the transport container (TC), consisting of the external thin-walled steel shell and the damping heat-proof layer from heat-resistant foam plastic. To justify the design parameters of such container, the tests for development and revision of the numerical model parameters were carried out. With use of this model the calculations were performed to calculate loads and the container response to 1

  12. Analysis of causes of combustible mixture explosions inside production floor areas

    Directory of Open Access Journals (Sweden)

    Lyapin Anton

    2016-01-01

    Full Text Available The work provides a cause analysis for major industrial explosions and a review of the causes of combustive air-gas mixture generation in a production environment. It has been established that during operation of explosive production facilities, it is process equipment that, as a rule, creates explosive environment inside the floor area. A qualitative method for determination of a potential accident has been reviewed. Analysis of the nature of explosion effect on building structures and equipment has shown that exposions characterised by absence of equipment and building structure disintegration normally have a localized character. It has been identified that during explosions inside process equipment, the largest structural damage occurs in spots hit by equipment debris. Complete destruction of building structures and equipment is caused by explosions inside equipment containing large quantities of combustible products. It has been identified that most explosions are accompanied by partial or total destruction of building structures and equipment. Therefore, measures taken to protect equipment and buildings from explosion effects lack efficiency.

  13. Compression stockings

    Science.gov (United States)

    Call your health insurance or prescription plan: Find out if they pay for compression stockings. Ask if your durable medical equipment benefit pays for compression stockings. Get a prescription from your doctor. Find a medical equipment store where they can ...

  14. Compression for radiological images

    Science.gov (United States)

    Wilson, Dennis L.

    1992-07-01

    The viewing of radiological images has peculiarities that must be taken into account in the design of a compression technique. The images may be manipulated on a workstation to change the contrast, to change the center of the brightness levels that are viewed, and even to invert the images. Because of the possible consequences of losing information in a medical application, bit preserving compression is used for the images used for diagnosis. However, for archiving the images may be compressed to 10 of their original size. A compression technique based on the Discrete Cosine Transform (DCT) takes the viewing factors into account by compressing the changes in the local brightness levels. The compression technique is a variation of the CCITT JPEG compression that suppresses the blocking of the DCT except in areas of very high contrast.

  15. Short term forecasting of explosions at Ubinas volcano, Perú

    Science.gov (United States)

    Traversa, P.; Lengliné, O.; Macedo, O.; Metaxian, J. P.; Grasso, J. R.; Inza, A.; Taipe, E.

    2011-11-01

    Most seismic eruption forerunners are described using Volcano-Tectonic earthquakes, seismic energy release, deformation rates or seismic noise analyses. Using the seismic data recorded at Ubinas volcano (Perú) between 2006 and 2008, we explore the time evolution of the Long Period (LP) seismicity rate prior to 143 explosions. We resolve an average acceleration of the LP rate above the background level during the 2-3 hours preceding the explosion onset. Such an average pattern, which emerges when stacking over LP time series, is robust and stable over all the 2006-2008 period, for which data is available. This accelerating pattern is also recovered when conditioning the LP rate on the occurrence of an other LP event, rather than on the explosion time. It supports a common mechanism for the generation of explosions and LP events, the magma conduit pressure increase being the most probable candidate. The average LP rate acceleration toward an explosion is highly significant prior to the higher energy explosions, supposedly the ones associated with the larger pressure increases. The dramatic decay of the LP activity following explosions, still reinforce the strong relationship between these two processes. We test and we quantify the retrospective forecasting power of these LP rate patterns to predict Ubinas explosions. The prediction quality of the forecasts (e.g. for 17% of alarm time, we predict 63% of Ubinas explosions, with 58% of false alarms) is evaluated using error diagrams. The prediction results are stable and the prediction algorithm validated, i.e. its performance is better than the random guess.

  16. Explosives Classifications Tracking System User Manual

    Energy Technology Data Exchange (ETDEWEB)

    Genoni, R.P.

    1993-10-01

    The Explosives Classification Tracking System (ECTS) presents information and data for U.S. Department of Energy (DOE) explosives classifications of interest to EM-561, Transportation Management Division, other DOE facilities, and contractors. It is intended to be useful to the scientist, engineer, and transportation professional, who needs to classify or transport explosives. This release of the ECTS reflects upgrading of the software which provides the user with an environment that makes comprehensive retrieval of explosives related information quick and easy. Quarterly updates will be provided to the ECTS throughout its development in FY 1993 and thereafter. The ECTS is a stand alone, single user system that contains unclassified, publicly available information, and administrative information (contractor names, product descriptions, transmittal dates, EX-Numbers, etc.) information from many sources for non-decisional engineering and shipping activities. The data is the most up-to-date and accurate available to the knowledge of the system developer. The system is designed to permit easy revision and updating as new information and data become available. These, additions and corrections are welcomed by the developer. This user manual is intended to help the user install, understand, and operate the system so that the desired information may be readily obtained, reviewed, and reported.

  17. 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)

  18. 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.

  19. Radioactive rare gases emission at underground nuclear explosions

    International Nuclear Information System (INIS)

    Dubasov, Yu.V.

    2016-01-01

    The examples of radioactive rare gases emission at underground nuclear explosions conducted in the USSR on the Novaya Zemlya and Semipalatinsk test sites are considered. It is pointed out that in the case of evasive explosion in vertical wells without apparent radioactive gases emission the samples of subsurface gas must contain the traces of radioactive rare gases. Under the inspection of evasive explosion in horizontal workings of rock massif, one should guided by the analysis of atmospheric air samples in the inspected area [ru

  20. 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 ...