Download or read book Theory and Modeling of Thermal Reaction Propagation in Beam Initiated Explosives written by J. B Aviles (Jr) and published by . This book was released on 1993 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: Previous work on the thermal initiation of energetic materials by particle beams concentrated on uniformly irradiated confined samples. The present report extends the work to situations where only a portion of the material has been irradiated. In some materials (e.g., TATB) only the irradiated region undergoes thermal initiation; in other materials a thermal initiation front has been observed (by thermocouple response) to propagate away from the irradiated region. The frontal speeds are of the order of centimeters per second to tens of centimeters per second. These slow speeds eliminate the possibility of pressure propagation or a deflagration to detonation transition (DDT). Modeling is based on the interference that at the thermal initiation temperature the material develops a greatly enhance thermal and gaseous diffusivity. This allows the exothermic energy released to propagate into the cold region and forestalls any explosive temperature rise. At a well defined positive R* (the explosion radius) thermal initiation propagation ceases and an explosive temperature rise takes place.
Download or read book Reaction Propagation Studies in Beam Initiated Confined Explosives written by and published by . This book was released on 1990 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments have been performed with the electron beam at the NRL linac in which confined explosives were partially irradiated to study how the reaction spreads radially from the hot central region to the cool outer regions. Four types of high explosives were studied: PBX-9404, PBXW-109, HBX-1, and TATB. Data were obtained with two sets of beam pulse parameters, and as a function of confinement window thickness. The results vary widely, from no reaction spreading at all in TATB to complete spreading and consumption in PBX-9404. The violence of the explosion increases with increasing confinement. Keywords: Plastic bonded explosives; Reaction kinetics; Threshold effect sensitivity; Nitrobenzenes.
Download or read book Thermal Initiation of High Explosives with an Electron Beam written by and published by . This book was released on 1979 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index written by and published by . This book was released on 1993 with total page 1834 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Modeling of Explosives and Propellants Second Edition written by Charles L. Mader and published by CRC Press. This book was released on 1997-08-29 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: Charles Mader, a leading scientist who conducted theoretical research at Los Alamos National Laboratory for more than 30 years, sets a new standard with this reference on numerical modeling of explosives and propellants. This book updates and expands the information presented in the author's landmark work, Numerical Modeling of Detonations, published in 1979 and still in use today. Numerical Modeling of Explosives and Propellants incorporates the considerable changes the personal computer has brought to numerical modeling since the first book was published, and includes new three-dimensional modeling techniques and new information on propellant performance and vulnerability. Both an introduction to the physics and chemistry of explosives and propellants and a guide to numerical modeling of detonation and reactive fluid dynamics, Numerical Modeling of Explosives and Propellants offers scientists and engineers a complete picture of the current state of explosive and propellant technology and numerical modeling. The book is richly illustrated with figures that support the concepts, and filled with tables for quick access to precise data. The accompanying CD-ROM contains computer codes that are the national standard by which modeling is evaluated. Dynamic material properties data files and animation files are also included. There is no other book available today that offers this vital information.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1986 with total page 756 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Non Equilibrium Zeldovich Von Neumann Doring Theory and Reactive Flow Modeling of Detonation written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper discusses the Non-Equilibrium Zeldovich - von Neumann - Doring (NEZND) theory of self-sustaining detonation waves and the Ignition and Growth reactive flow model of shock initiation and detonation wave propagation in solid explosives. The NEZND theory identified the non-equilibrium excitation processes that precede and follow the exothermic decomposition of a large high explosive molecule into several small reaction product molecules. The thermal energy deposited by the leading shock wave must be distributed to the vibrational modes of the explosive molecule before chemical reactions can occur. The induction time for the onset of the initial endothermic reactions can be calculated using high pressure, high temperature transition state theory. Since the chemical energy is released well behind the leading shock front of a detonation wave, a physical mechanism is required for this chemical energy to reinforce the leading shock front and maintain its overall constant velocity. This mechanism is the amplification of pressure wavelets in the reaction zone by the process of de-excitation of the initially highly vibrationally excited reaction product molecules. This process leads to the development of the three-dimensional structure of detonation waves observed for all explosives. For practical predictions of shock initiation and detonation in hydrodynamic codes, phenomenological reactive flow models have been developed. The Ignition and Growth reactive flow model of shock initiation and detonation in solid explosives has been very successful in describing the overall flow measured by embedded gauges and laser interferometry. This reactive flow model uses pressure and compression dependent reaction rates, because time resolved experimental temperature data is not yet available. Since all chemical reaction rates are ultimately controlled by temperature, the next generation of reactive flow models will use temperature dependent reaction rates. Progress on a statistical hot spot ignition and growth reactive flow model with multistep Arrhenius chemical reaction pathways is discussed.
Download or read book China written by World Bank and published by World Bank Publications. This book was released on 1993 with total page 1422 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Republic of Korea's industrial policy has directed that nation's economy through nearly three decades of spectacular growth. But the authors of this paper maintain that this policy is showing signs of being outmoded. The time has come, the authors argue, for the Korean government to stop managing the economy's structural development and to redefine the responsibilities of business and government. Under this proposed compact, the allocation of resources would shift from the government to the private industrial and financial sectors. The transformation of the government bureaucracy from an ad hoc policy role to one of a transparent and predictable regulator is a key to the success of this undertaking. These new directions would present the government with enormous challenges. Greater competitive discipline and regulatory oversight would be required. While dealing with the complexities of the transition, the government would have to maintain macroeconomic stability and the momentum of savings and investment. For comparison, the study examines the industrial economies of France, Germany, Japan, and the United States, which underwent similar shifts.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1991 with total page 1460 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Proceedings written by and published by . This book was released on 1989 with total page 830 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thermal Initiation of Confined Primary Explosives with a Proton Beam written by and published by . This book was released on 1989 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: The thermal initiation characteristics of the primary explosives lead azide and lead styphnate have been studied by heating confined samples with a 200-MeV proton beam. Values were obtained for thermal initiation thresholds, explosion temperatures, and average specific heats. Thresholds and explosion temperatures, and average specific heats. Thresholds and explosion temperatures were found to depend strongly on the beam heating rate. Keywords: Explosives; Proton beam; Thermal initiation.
Download or read book A Lattice Dynamical Model of Thermal Initiation of Solid Explosives written by F. J. Owens and published by . This book was released on 1977 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is proposed that the thermal initiation of a solid explosive results from a chemical reaction between the ions of the lattice induced by large amplitude vibrations of the ions at the initiation temperature. Such vibrations would allow the ions of the lattice to approach each other enabling chemical reaction to occur. The large amplitude vibrations are possible in a solid in which lattice potentials are softer and more anharmonic. Reaction rates for this mechanism are formulated in terms of the force constants of the normal modes of vibration for the case of a simple cubic solid. Comparison of available lattice dynamical data, such as neutron diffraction and Raman studies for the isostructural pair KN3 and TLN3, the latter of which is unstable, support the possibility of softer and more anharmonic potentials in explosive solids. (Author).
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1993-10 with total page 1662 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Three Dimensional Modeling of Shock Initiation of Heterogeneous Explosives written by and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The basic processes in the shock initiation of heterogeneous explosives have been investigated theoretically using a model of a cube of nitromethane containing 91 cubic air holes. The interaction of a shock wave with the density discontinuities, the resulting hot spot formation and interaction, and the buildup to propagating detonation were computed using three-dimensional numerical Eulerian hydrodynamics with Arrhenius chemical reaction and accurate equations of state. The basic process in the desensitization of a heterogeneous explosive by preshocking with a shock pressure too low to cause propagating detonation was numerically modeled.
Download or read book Characterization of High explosive Initiation and Safety at Los Alamos written by and published by . This book was released on 1994 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Chapman-Jouget and ZND models of steady detonation have proved most useful for engineering estimation of the propagation of near-planar, steady detonation in short-reaction-zone explosives. However, even in well characterized systems, the purposeful initiation of detonation is not described by these models. The highly divergent and microscopic nature of point initiation require discerning experiments, modeling, and theoretical analysis. Recently, safety considerations in complex or damaged systems, possibly containing long-reaction-zone (insensitive) high explosives, have dominated the author's thinking. These situations are rarely planar or steady, the physical state of the explosive may not be easily characterized, and there is a wide range of potential stimuli. The high-explosive reaction may range from none, to deflagration, to partial detonation, or to full detonation. Techniques and data applicable to estimating the level of response are needed.
Download or read book Numerical Modeling of Insensitive High explosives Initiation written by and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The initiation of propagating, diverging detonation is usually accomplished by small conventional initiators. As the explosive to be initiated becomes more shock insensitive, the initators must have larger diameters to be effective. Very shock-insensitive explosives have required initiators larger than 2.5 cm. We have numerically examined the process of initiation of propagating detonation as a function of the shock sensitivity of the explosive using the two-dimensional Lagrangian reactive hydrodynamic code 2DL and the Forest Fire rate to describe the shock initiation process of heterogeneous explosives. The initiation of propagating detonation in shock-insenstive explosives containing triamino trinitrobenzene results in large regions of partially decomposed explosive even when initiated by large initiators. The process has been observed experimentally and reproduced numerically.
Download or read book Sa han och sa hon written by and published by . This book was released on 1890 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt:
