Heat Sensitization of Explosives and

Detonation, Heat Sensitization of Explosives and Memory Effect. It has been known for some time that certain expls exhibit a 

Ubbelohde (Ref 5) found that the total induction period of Lead Azide which is heated at a given temp T is practically the same whether measured in one or more stages 

Jones Jackson of Picatinny Arsenal (Ref 6) carried out experiments using the same procedure as that of Ubbelohde et al (Ref 4) except that a Cu rather than an Al sample holder was used. They performed two types of experiments a) measurements of the induction period as a function of temp for several common expls and b) examination of these expls to det which of them show the memory effect . Jones Jackson reported that the memory effect is not found with all primary expls (eg Tetracene) and it is found with some HE s, but not all. Some of the props which might 

Parlin et al (Ref 3) treated the thermal decompn of solid expls as a first order reaction and arrived at an explicit expression for the induction period 

Explosives E Kcals/mole + 1°gl0B Shows Memory Effect MP(°C) Kinetics of Thermal Decomposition 

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A plot of logio Ed against 1/1) is almost rectilinear. Therefore, Ea may be determined by equating (EJ4.57) with the slope of the straight line. Equation 3.3 holds good for a number of explosives such as lead azide, cuprous azide, mercury fulminate, lead styphnate, barium styphnate and metal picrates and metal picramates etc. [25-30]. Thus, it appears that the determination of Ea gives a more complete picture concerning the heat sensitivity of explosives than ED or ET. 

There are many potential causes of explosions and fires at industrial sites handling hazardous substances (a) chemical reactions that produce explosion, fire, or heat (b) ignition of explosive or flammable chemicals (c) ignition of materials due to oxygen enrichment (d) agitation of shock- or friction-sensitive compounds and (e) sudden release of materials under pressure [21,29]. 

Dunkle s Syllabus (1957-1958) Shock Tube Studies in Detonation (pp 123-25) Determination of Pressure Effect (144-45) Geometrical and Mechanical Influences (145-48) Statistical Effects of Sensitivity Discussion on Impact Sensitivity Evaluation (148-49) Pressure in the Detonation Head (175) Temperature of Detonation (176) Charge Density, Porosity, and Granulation (Factors Affecting the Detonation Process) (212-16) Heats of Explosion and Detonation (243-46) Pressures of Detonation (262-63) A brief description of Trauzl Block Test, Sand Test, Plate Dent Test, Fragmentation Test, Hess Test (Lead Block Crushing Test), Kast Test (Copper Cylinder Compression Test), Quinan. Test and Hop-kinson Pressure Bar Test (264-67) Detonation Calorimeters (277-78) Measurements... 

Andrej Ma ek, "Sensitivity of Explosives , ChemRevs 62, 41-63(1962). "The sensitivity of an explosive can be defined as the minimum amount of energy that must be imparted to the explosive, within limited time and space, to initiate explosive decomposition (p 60). This definition can serve as a basis of quantitative fundamental treatments provided the imparted energy is thermal and provided its initial distribution in time and space is known. If the energy is not supplied directly as heat, but by mechanical means (such as a shock), there is the additional requirement of quantitative assessment of conversion of the stimulus into heat (p60)... 

Sensitivity to heat is expressed in terms of the temperature at which ignition, explosion or flashing of an explosive occurs. The application of heat is the simplest way of initiation of explosives and leads to explosion when heat is liberated by a reaction at a greater rate than heat is lost [39]. This has been discussed in detail... 

Sensitivity of Explosives to Heat, Impact, Friction, Spark and Shock... 

A comparative evaluation of heat sensitivity of different explosives can be obtained by determining (a) explosion delay (TD) or induction period (b) explosion temperature ( T) and (c) activation energy ( a) which are related to each other. 

These compounds, according to the US NavOrdLab Memorandum 10068, 3/24/1949, are characterized by low mp, good heat stability and moderate sensitivity Aliphatic Amines and Imines, Nitrated Derivatives. A number of these compds are of interest in the field of explosives and are discussed under the individual compds, such as amino methane, aminoethane, amino-guanidine, etc... 

A shock- and heat-sensitive high explosive that evolves much flame. Highly dangerous. Upon decomposition it emits highly toxic fumes of NOx. See also NITROSAMINES and EXPLOSIVES, HIGH. 

The sensitivity of explosives to heating, naked flame, impact and friction is decisive in the international rules for railway traffic RID (Reglement International Concemant le Transport des Marchandises Dangereuses) [65]. Analogous rules ADR are concerned with international motor traffic [66]. 

Cherville and associates [44] have examined a number of explosives in a mass spectrograph. Particularly important and reproducible were results at 77K. The formation of NOj was readily established in the spectrograms. The authors introduced a concept of the radiochemical yield of formation of NOj. A considerable difference exists between the values of of nitramines and nitroaromatics. They correlated the values of Gnoj with those of the sensitivity of explosives to impact, friction and high temperature (temperature of initiation f at the rate of heating 5 C/min) Table 9. 

This chapter is concerned with data on the sensitivity of explosive azides to heat, nuclear, and other intense radiation. These stimuli, when directed at solid explosives, may have very similar consequences, even though they may have very different origins. The parallelism is attributable to the conversion and degradation processes which occur when powerful stimuli impinge on condensed matter. 

Table VI gives data obtained for RD 1333 lead azide. A statistical analysis using the 11 data points in the table gives a mean of AT of 15°C with a standard deviation of 2°. The 95% confidence interval is 1.3°. The importance of making more than one measurement is made clear because the 95% confidence interval for a single measurement using the same mean and standard deviation is 4°. If we compare data for lead azides (Table VII) for heating rates of 5° and 10°/min, dextrinated material is significantly more sensitive than the other products tested. The explosion temperature is also significantly lower. A higher heating...

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