Thermochemical Characteristics

In general, pyrolants composed of a polymeric material and AN particles are smokeless in character, their burning rates are very low, and their pressure exponents of burning rate are high. However, black smoke is formed as i decreased and carbonaceous layers are formed on the burning surface. These carbonaceous layers are formed from the undecomposed polymeric materials used as the matrix of the pyrolant. When crystalline AN particles are mixed with GAP, GAP-AN pyrolants are formed. Since GAP burns by itself, the GAP used as a matrix for AN particles decomposes completely and bums with the oxidizer gases generated by the AN particles. 

The combustion products of aluminized GAP-AN pyrolants at 10 MPa are HjO, Hj, Nj, GO, GOj, and AI2O3. The mass fraction of AljOj increases linearly while that of HjO decreases linearly with increasing Iai- This is caused by the overall reaction of 2A1 -I- 3H2O AI2O3 -t 3H2. 

The burning rate decreases with increasing constant pressure, especially in the range 123 (0.3-0.5). The effect of the addition of AN on the pressure exponent of burning rate, n, is significant n = 0.70 at 1.05 at 123 (0.3), and 0.78 at 

The burning rate decreases with increasing Ian at constant pressure, especially in the range The effect of the addition of AN on the pressure exponent of 

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The combustion wave of a premixed gas propagates with a certain velocity into the unburned region (with flow speed = 0). The velocity is sustained by virtue of thermodynamic and thermochemical characteristics of the premixed gas. Figure 3.1 illustrates a combustion wave that propagates into the unburned gas at velocity Mj, one-dimensionally under steady-state conditions. If one assumes that the observer of the combustion wave is moving at the same speed, Wj, then the combustion wave appears to be stationary and the unburned gas flows into the combustion wave at the velocity -Wj. The burned gas is expelled downstream at a velocity of-M2 with respect to the combustion wave. The thermodynamic characteristics of the combustion wave are described by the velocity (u), pressure (p), density (p), and temperature (T) of the unburned gas (denoted by the subscript 1) and of the burned gas (denoted by the subscript 2), as illustrated in Fig. 3.1. 

The thermochemical characteristics of l,3,5-trinitro-l,3,5-triazepane, such as energies of dissociation of N-NOz bonds, enthalpies of formation, vaporization, and combustion, as well as enthalpy of formation of amine radicals, have been determined <2004MI92>. The rate constants of initial monomolecular stages of thermal decomposition in the solid phase were measured for its furazano-fused analog 20 <1999RCB1250> and the ratio of the rate constants of decomposition in the melt and solid states, characterizing the reaction retardation in the crystal lattice, was determined. The kinetics of the thermal decomposition of 20 has also been studied <1995MI885>. 

As the decomposition reaction progresses, it produces energy in the form of heat. For a given quantity of explosive, the faster the rate, the greater the rate of heat evolved. Combining the thermochemical characteristics of the reaction with the rate of reaction yields an expression for the rate of energy, or heat, produced. 

The decomposition reactions dealt with in these equations are strongly a function of the characteristics of the particular explosive charge. Particle size and surface area, the presence of chemical impurities, and other often uncontrollable factors all affect the decomposition reaction mechanism and hence its rate and thermochemical characteristics. Values o Ea, A//, and Z are not readily available in the literature, and often must be experimentally determined for the particular batch of explosives of interest. 

The conditions necessary to achieve DDT depend upon such factors as confinement, particle size, particle surface area, packing density, charge diameter and length, heat transfer, and thermochemical characteristics of the particular explosive. 

Measured Thermochemical Characteristics (Parameters) of Three OCM Catalysts... 

It is necessary to acknowledge that some existing experimental data indicates that oxygen can be removed from Li/MgO directly during the reduction in hydrogen at temperatures as low as 873 K (see, for instance, Leveies, 2002). Such discrepancies with the data described above might be due to some difference in catalyst preparation/pretreatment procedures, which leads to the formation of active sites with somewhat different thermochemical characteristics. What is important is to attribute the evaluated kinetic parameters to the catalysts of particular thermochemistry. 

We believe that the major motivations for unraveling the mechanism of decomposition consists in its subsequent use for interpretation and prediction of the kinetics under different conditions of interest to the researcher, i.e., in the possibility of theoretical estimation of the thermochemical characteristics... 

Second, these equations take into account, besides temperature, a variety of factors affecting the decomposition kinetics, such as the composition, stoichiometry, and thermochemical characteristics of the reaction, the pressure of the excess gaseous products and of the foreign (inert) gas in the reactor, and even, physical properties of the reactant (the size of particles, molar mass, and density). 

An interpretation of the mechanism of analyte retention on the furnace surface has been one of the most controversial problems in ET A AS for years. Since the first studies in this field in the 1970s, two different mechanisms have been suggested. According to the first one, the adsorption/desorption mechanism, it is supposed that the anal de is distributed on the furnace surface in the form of a monolayer of free atoms or molecules, retained on the surface by means of physical or chemical adsorption forces. According to the second one, the condensation/evaporation mechanism, the sample is distributed in a form of solid microparticles retaining all the thermochemical characteristics of the original (bulk) substance. 

Chemical interference will occur when the analyte element forms with another element, radical, or compound a new compound in the condensed phase and this new compound possesses different thermochemical characteristics. The interference becomes greater with increasing difference in the dissociation temperatures of the original and new compounds. Dissociation is dependent on the flame temperature, the ratio of oxidant/fuel gas, the concentration of the analyte element, the efficiency of the nebulizer, and the measurement height in the flame. 

ENs have been calculated for all elements in different valence states according to Eqs 2.91, 2.89 and 2.92, showing good agreement with the thermochemical characteristics. 

Let us consider the vdW interaction in helium in detail. Liquid helium is the only substance that does not solidify down to 0 K in the absence of external pressure. This is explained by the quantum character of the substance, whose zero point energy (ZPE) exceeds the crystal lattice energy [30]. At the same time, the macroscopic properties of helium (its crystal structure and thermochemical characteristics) do not differ fundamentally from those of other rare gases this allows to treat it in classical terms. Table 4.1 lists the structural and thermodynamic properties of rare gas molecules and crystals (see also [31]). 

Densities and thermochemical characteristics of the azohum azolates are given in Table 4. When 5-nitro-tetrazolate was used as the anion, the melting points of the compounds were lower than those of the corresponding... 

These salts were characterized by IR, Raman and NMR spectroscopy, mass spectrometry, elemental analysis. X-ray, and initial safety testing (impact and friction sensitivity). Low impact sensitivities were demonstrated. Densities and thermochemical characteristics of substituted amino, amino-methyl, and polymethyl tetrazolium salts are summarized in Table 5. All of these new salts exhibit thermal stabilities > 170°C based on DSC/TGA studies (except the azide). The densities of l-amino-4,5-dimethyl tetrazolium perchlorate (45b) and l-methyl-4,5-diamino tetrazolium dinitramide (50b) are markedly higher than the others. 

Agroskin, A.A., Artamonova, E.V., Goncharov, E.I., Tyagunov, V.M., and Valyavin, G.G. (1978) Thermochemical characteristics of petroleum residue coking. Chem. Techn. Fuels Oils, 14, 412-415. 

The thermochemistry and thermal effects of reactions involving dithio-phosphoric acids have been analyzed and the formation enthalpies of a series of dithiophosphates determined. Analysis of the resulting experimental data was carried out on the basis of an additive scheme. Group contributions into the vaporization and formation enthalpies were determined and thermochemical characteristics of the compounds were calculated. 

The establishment of connection between the structure and thermochemical parameters, as well as kinetic and thermochemical characteristics of interacting systems is of great importance [4, 5]. But the analysis of dependences between main parameters of chemical thermodynamics and spatial-energy characteristics of free atoms is still topical. 

Larina, V.N., Uryash, V.F., Kokurina, N.Yu., and Novoselova, N.V., Influence of degree of order on thermochemical characteristics of cellulose and solubility of water in it, 17-th International Conference on Chemical Thermodynamics in Russia Proceedings, Kazan KSTU Publ., 2009, vol.l, p.lOO (in Russian). 

Mass spectrometry is a unique method that allows study of the reactivity of isolated metal-containing ions in the gas phase in the absence of solvent. A number of fundamental thermochemical characteristics of organometallic molecules and ions, such as ionization energies, proton affinities, electron affinities and metal-ligand bond dissociation energies, can be determined from mass spectrometry experiments. 

Introduction. This chapter contains discussions of military high explosive compounds. The explosives are arranged by chemical class. The chemical, physical, and thermochemical characteristics, sensitivity, performance, and stability are discussed for each explosive. The chemical stmcture of each compound is given, and for composition explosives, the ingredients are given. The method of manufacture is also given. 

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