Physical explosion described

Application of physical explosions, while important, are less so than those of the chemical types, described below... 

Effects of the Physics Structure and the State of Aggregation on the Detonating Capacity of Explosives. Described in die paper of Apin Bobolev, listed in Vol 4, p D257... 

The explosives described above are aU liquid at room temperature, and their physical properties such as melting point, density as well as viscosity are closely related to the content of nitrogen, as illustrated in Table 7.37. 

In this paper we describe a mathematical model of melt/water physical explosions. This model has been developed to study the escalation and propagation stages of a vapor explosion. After describing the physics of this problem, we give a complete description of the conservation equations and constitutive relations that form the model. We then describe the the solution procedure and present some results from simulations that have been performed to study the effect of the presence of permanent gas in the coarse mixture and to compare our predictions using an approximate equation of state (EOS) with those using a standard steam table package. 

Many types of outcomes are possible for a release. This includes vapor cloud explosions (VCE) (Section 3.1), flash fires (Section 3.2), physical explosions (Section 3.3), boiling liquid expanding vapor explosions (BLEVE) and fireballs (Section 3.4), confined explosions (Section 3.5), and pool fires and jet fires (Section 3.6). Figure 3.1 provides a basis for logically describing accidental explosion and fire scenarios. The output of the bottom of this diagram are various incident outcomes with particular eflfects (e.g., vapor cloud explosion resulting in a shock wave). 

The physical models described in Chapter 2 generate a variety of incident outcomes that arc caused by release of hazardous material or energy. Dispersion models (Section 2.3) estimate concentrations and/or doses of dispersed vapor vapor cloud explosions (VCE) (Section 3.1), physical c q)losion models (Section 3.3), fireball models (Section 3.4), and confined explosion models (Section 3.5) estimate shock wave overpressures and fragment velocities. Pool fire models (Section 3.6), jet fire models (Section 3.7), BLEVE models (Section 3.4) and flash fire models (Section 3.2) predict radiant flux. These models rely on the general principle that severity of outcome is a function of distance from the source of release. 

Free acid present in equipment requires neutralization as well as washing and a five percent solution of sodium carbonate (soda ash) is used for this purpose. Because of the uncertainty of complete removal of explosives in all cases by the physical methods described, chemical methods are used also to supplement these. Standard decontamination procedures include the decontaminating chemical shown by table 15-4. 

The explosion could have been prevented by isolating the reactor by slip-plates or physical disconnection. This incident and the others described show that valves are not good enough. 

The term risk assessment is not only used to describe the likelihood of an ad crse response to a chemical or physical agent, but it has also been used to describe the likelihood of any unwanted event. This subject is treated in more detail in tlie next Part. These include risks such as explosions or injuries in tlie workplace natural catastrophes injury or deatli due to various voluntary activities such as skiing, sky diving, flying, and bimgee Jumping diseases deatli due to natural causes and many others. ... 

Fire and explosion models describe the magnitude and physical effects (heat radiation, explosion overpressure) resulting from a fire or e.xplosion. 

Effect models describe the impact of the physical effects of a fire, e.xplosion, or toxic gas release on exposed people, the environment or property, based on the results of tlie source, dispersion, and fire and explosion models. 

Molex no s 2 3 are physical mixts of AN 52—84, K perchlorate 0—20, DNT oil 7—12, baked cork 1—10, A1 powd 5—7 Ca carbonate 1%. They exhibited satisfactory sensitivity to impact, friction, flame initiation, and had excellent stability. Philips (Ref 4) reported on tests of Molex B and BB , manufd by the National Explosives Co. They are described as physical mixts of AN 80.77—85.06, flake A1 6.02—6.10, DNT oil 4.32—5.84, activated cork 2.55—4.47, Ca stearate 1.10—1.99 and Ca carbonate 0.83-0.95%. They were shown to be stable, to have fairly high brisance, but to be sufficiently sensitive to expl in the rifle bullet impact test. Byers (Refs 1 3) describes blasting expls similar in compn... 

In recent years PETN sheet explosive, consisting of PETN in a rubber-like elastic matrix, has found considerable use in metal-forming, metalcladding and metal-hardening. Physical expl characteristics of rubber-bonded sheet expl are described by W. Kegler R. Schall (Ref 45, p 496), by Kegler (Ref 59), and in Refs 30c,... 

A mechanism of action describes the molecular sequence of events (covalent or non-covalent) that lead to the manifestation of a response. The complete elucidation of the reactions and interactions among and between chemicals, include very complex and varied situations including biological systems (macromolecular receptors, physical phenomena (thermodynamics of explosions) or global systems (ozone depletion). Unfortunately, this level of mechanistic detail is often unavailable but recent advances in molecular toxicology and others hazards, at the molecular level, have provided valuable information that elucidates key steps in a mechanism or mode of action. ... 

The heat of decomposition (238.4 kJ/mol, 3.92 kJ/g) has been calculated to give an adiabatic product temperature of 2150°C accompanied by a 24-fold pressure increase in a closed vessel [9], Dining research into the Friedel-Crafts acylation reaction of aromatic compounds (components unspecified) in nitrobenzene as solvent, it was decided to use nitromethane in place of nitrobenzene because of the lower toxicity of the former. However, because of the lower boiling point of nitromethane (101°C, against 210°C for nitrobenzene), the reactions were run in an autoclave so that the same maximum reaction temperature of 155°C could be used, but at a maximum pressure of 10 bar. The reaction mixture was heated to 150°C and maintained there for 10 minutes, when a rapidly accelerating increase in temperature was noticed, and at 160°C the lid of the autoclave was blown off as decomposition accelerated to explosion [10], Impurities present in the commercial solvent are listed, and a recommended purification procedure is described [11]. The thermal decomposition of nitromethane under supercritical conditions has been studied [12], The effects of very high pressure and of temperature on the physical properties, chemical reactivity and thermal decomposition of nitromethane have been studied, and a mechanism for the bimolecular decomposition (to ammonium formate and water) identified [13], Solid nitromethane apparently has different susceptibility to detonation according to the orientation of the crystal, a theoretical model is advanced [14], Nitromethane actually finds employment as an explosive [15],... 

Attrition of particulate materials occurs wherever solids are handled and processed. In contrast to the term comminution, which describes the intentional particle degradation, the term attrition condenses all phenomena of unwanted particle degradation which may lead to a lot of different problems. The present chapter focuses on two particular process types where attrition is of special relevance, namely fluidized beds and pneumatic conveying lines. The problems caused by attrition can be divided into two broad categories. On the one hand, there is the generation of fines. In the case of fluidized bed catalytic reactors, this will lead to a loss of valuable catalyst material. Moreover, attrition may cause dust problems like explosion hazards or additional burden on the filtration systems. On the other hand, attrition causes changes in physical properties of the material such as particle size distribution or surface area. This can result in a reduction of product quality or in difficulties with operation of the plant. 

Using the results of Problem 12-13, determine the vessel wall thickness required to contain an explosion in another vessel that is physically connected to the first vessel with a 1-in pipe. Describe why the second vessel requires a greater wall thickness. 

The types of explosions that may occur depend on the confinement of the reactive material, its energy content, its kinetic parameters, and the mode of ignition (self-heating or induced by external energy input). Explosions are characterized as physical or chemical explosions, and as homogeneous or heterogeneous as described in Figure 2.2. 

Both deflagrations and detonations can produce what a lay observer might describe as an explosion . Nonetheless, a detonation is a special type of explosion with specific physical characteristics. It is initiated by the heat accompanying shock compression it liberates sufficient energy, before any expansion occurs, to sustain the shock wave. The shock wave propagates into the unreacted material at supersonic speed, typically 1500—9000 m/s. We discuss the practical differences between the effects of detonation and deflagration in Chapter 11 on post-blast issues. 

This correction plays a key role in any cosmological application. Without it, SNIa events could not be used as distance indicators. However, its purely empirical nature remains unsatisfactory to demanding theoretical minds. We would like to be able to explain physically why some explosions are weaker than others, and what effect this has on the appearance of the object. This involves building detailed models of these explosions and the way radiation is hansferred through the expanding envelope, similar to those made to describe atomic bombs or spheres struck by laser beams, which implode before exploding. 

The process is described in detail by Paterson (Ref 1) and its resume is given by Dunkle (Ref 2) When a detonation wave Sj initiated within a volume of explosive reaches its surface, a shock wave Sj proceeds into the surrounding medium (or target). At the same time, a wave S2 is-reflected into the detonation products this wave is either a shock or rarefaction depending on the physical properties of these products and of the target... 

Besides physical (which includes mechanical and electrical and chemical explosions, there is also atomic (or nuclear) explosion, already described in Vol 1, p A501-R (Ref 8)... 

Using the equation P/p = const for the isentrope with y = 2.77, W.E. Deal conducted "Measurement of the Reflected Shock Hu-goniot and Isentrope for Explosive Reaction Products , as described in the Physics of Fluids, 1, 5 23-27(1958). With the same equation, but different y values, Deal deter-... 

Determination of moisture content is described in Section 8, ANALYTICAL PROCEDURES, ETC", where are listed numerous US Military Specifications. These specs contain also a brief description of required physical tests. Before describing the specification requirement tests, a resume is given of "Measuring Techniques" of fuze explosive components, as discussed in NOLTR 1111(1952), pp 9-1 to 9-56 (Ref 11) The mea surement of fuze component performance consists mainly of a determination of (a) the input characteristics, and (b) the output characteristics... 

Wiley, NY (1938) (No specific pages for history) 28a) J. Reilly, Explosives, Matches and Fireworks , VanNostrand, NY (1938) (Describes various physical expl tests)... 

Brief mention of impact machines is made under Physical Tests in Vol 1, p XVII. Because there are many literature references to the following impact machines, and not because they are inherently better than any others, we will now describe the following Explosives Research Laboratory (ERL), Rotter, Bureau of Mines (BOM) Picatinny Arsenal (PicnArsn)... 

Explosion has several attributes and hence can be described ot defined in different ways- From the standpoint of chemistry it is a rapid cheuircai process resulting in the evolution of gas and heat. To the classic physical definition of a high-pressure energy release must be added thermonuclear effects. Both chemical and physical concepts must be combined to obtain a complete terminology Ref H. Pessiak, Explosivstoffe, 1960, 23—6, 45-7... 

Burning (or Combustion) Rate Test and Burning Tesi.are described by Ch.E. Munroe J-E. Tiffany on pp 30-31 of Physical Testing of Explosives", USBurMines Bulletin 346, Govt prtg Off, Washington, DC (1931)... 

There are also descriptions of physical tests and analytical procedures under explosives of military or commercial interest and of raw materials. If any US Military Specifications are issued, their requirements and tests are described... 

Experimental procedures for determination of gaseous products of expls on exploding, by means of Bichel Pressure Gage and Crawshaw-Jones Apparatus are described in Ref 1, but no compns of gases are given Refs 1) Ch.E. Munroe J.E. Tiffany, "Physical Testing of Explosives", USBur-Mines Bull 346(1931), 91-99 2) A. Stett-... 

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