Temperature in shock wave

Attenuation (decay) of shock waves (Refs 10, 37, 46, 77) Energy in shock waves (Refs 40 72) Ionization in shock waves (Ref 53) Light (luminescence) produced by shock waves (Refs 19 21) Spectra of shock waves (Ref 30) Temperature in shock waves (Refs 9, 38 48) Velocity of shock waves (Refs 18a, 24 ... 

Production of High Temperatures in Shock Waves ,pp 53-58 in "Proceedings of the Symposium on High Temperature - A Tool for the Future , StanfordResInst, Berkeley, Calif, 25, 26 27 June (1956), Menlo Park, Calif (1956) 39) R.A. Strehlow, "One... 

It is expected [Cadle and Allen (28)] that HS would be rapidly oxidized in the atmosphere to form a number of products such as S02, SO, and H2SO. The mechanisms for such reactions have been studied at high temperatures in shock waves by Bradley and Dobson (25). 

Maleic anhydride undergoes spontaneous polymerization when heated (100-170°C) under pressure >20,000 atm.Polymerization was also observed when monomer was subjected to intense transient high pressures and temperatures in shock waves generated by detonation.Polymer yields were quite low and remained constant for a wide range of initial temperatures... 

In the thermal decomposition of N2H4 in shock waves, NH(X) is formed in secondary reactions [20]. In shock-heated NH3-noble gas mixtures at high temperatures (T>3000 K) [37 to 39] and in a high-temperature plasma (T = 3200 K), emission from NH(A) was observed [40]. At lower temperatures in shock waves NH(X) was observed [41]. HN3 and HNCO can be pyrolyzed at significantly lower temperatures (T> 1200 K) under these conditions mainly NH(X) is formed [44, 45]. 

The reaction NH2 + O2 was studied at high temperatures in shock waves [66 to 68]. The induction period for the appearance of OH absorption and the consumption of NH3 was measured in shock-heated NH3-O2 mixtures in the temperature range 1500 to 2800 K an activation energy of = 178 kJ/mol was obtained for the reaction NH2 + 02 NH + H02 [67]. The kinetics of ammonia oxidation in reflected shock waves was followed by observing the induction period. Computer simulation of the NH3-O2 system with the reaction scheme... 

Glanzer K, Quack M and Tree J 1977 High temperature UV absorption and recombination of methyi radicais in shock waves 16th Int. Symp. on Combustion (Pittsburgh The Combustion institute) pp 949-60... 

S.E. Arione and G.E. Duvall, Temperature Dependence of the Precursor Amplitude in <111 > Lithium Fluoride, in Shock Waves in Condensed Matter (edited by Y.M. Gupta), Plenum, New York, 1986, pp. 299-302. 

Grady, D.E., Temperature and Deformation Micostructure in the Shock Transition, in Shock Waves in Condensed Matter—1983 (edited by Asay, J.R., Graham, R.A., and Straub, G.K.), North-Holland Physics, Amsterdam, 1984, pp. 363-367. 

Modica and LaGraff1have conducted a series of examinations of the production and kinetic aspects of the reactions of CF2 in shock waves. C2F4, diluted 1 100 with argon, was shocked over the temperature range 1200—1800 °K. Ultraviolet absorption of the shocked mixture revealed that dissociation of the C2F4 to CF2 was virtually complete within 1 jusec. The dissociation reaction was found to be second order,... 

The cubic y-modification has been recently observed under a pressure of 15 GPa and temperatures above 2000 K by the laser heating technique in a diamond cell [23] and in shock-wave compression experiments with pressures >33 GPa at 1800 K and >50 GPa at 2400 K [29]. This modification is often designated as the c-modification in the literature in analogy to the cubic boron nitride (c-BN). It has a spinel-type structure in which two silicon atoms are octahedrally coordinated by six nitrogen atoms, one silicon atom is coordinated tetrahedrally by four nitrogen atoms (Fig. 3c). The atomic coordinates for the cubic modification are given in Table 2. From calculations it is shown that this structure should have a high hardness similar to that of diamond and c-BN [23]. 

Bradley and Dobson have recently examined the oxidation of hydrogen sulfide in shock waves. Of interest here is their observation that at high temperatures (above 1700 °K) the SO2 formed appeared before the OH, whereas at lower temperatures the two species appeared simultaneously. They interpreted these results in terms of an additional reaction at higher temperatures which could lead to SO2 formation without OH, namely... 

Recently, Bradley and Dobson studied the oxidation of hydrogen sulfide in shock waves over the temperature range 1350-2450 °K. They monitored the absorption spectra of OH and SO2. The significant results of their experiments were that at the lower temperatures (below 1560 °K), the OH and SO2 appeared simultaneously, after an induction period, whereas above 1700 °K the SO2 appeared earlier than OH. They explained their results by the thermal dissociation of H2S followed by reactions (30), (43), (44), (45), (28) and (55) at the low temperatures, where reaction (55) is... 

Patterson and Greene have decomposed BrCN in shock waves over a temperature range 2500-7000 °K. Kinetic data consisted of emission profiles of excited CN, v = Q, y = 1) and C2( Hg, r = 0 v = 0)... 

This model is based on quasimolecular dynamics, in which the medium is assumed to be composed of an assembly of meso-scale discrete particles (i.e., finite elements). Tlie movement and deformation of the material system and its evolution are described by the aggregate movements of these elements. Two types of basic characteristics, geometrical and physical, are considered. In tlie geometrical aspect, sliapes and sizes of elements and tlie manner of their initial aggregation and arrangement are the important factors. In the physical aspect, mechanical, physical, and chemical characteristics, such as the interaction potential, phase transition, and chemical reactivity may be tlie important ones. To construct this model, many physical factors, including interaction potential, friction of particles, shear resistance force, energy dissipation and temperature increase, stress and strain at the meso- and macro-levels, phase transition, and chemical reaction are considered. In fact, simulation of chemical reactions is one of the most difficult tasks, but it is the most important aspect in shock-wave chemistiy. 

E. F. Greene and J. P. Toennies, Chemical Reactions in Shock Waves, Academic Press, New York, 1964 A. G. Gaydon and I. R. Hurie, The Shock Tube in High-Temperature Chemical Physics, Reinhold, New York, 1963. 

HNO3 has been pyrolysed in shock waves in the presence of NO2, and the formation of HO2 in reaction (6) was monitored by the u.v. absorption. From the yields and lifetimes of HO2, a rate constant, (4.5 l)x 10 cm moE s for reaction (7) was derived in the temperature range 1350—1700 K. The interaction of H2O vapour under electrical discharge with aqueous NO3 and NO2 leads to a steady-state ratio of the two ions, irrespective of whether the starting solution contains only NO3, NO2, or their mixture. This ratio varies with the pH of the solution. The steady states attained due to electrical discharge and to radiolysis are closely similar, and the same sequences of reactions with virtually identical mechanisms are probably involved in the two methods. ... 

Only at very high temperatures (T dSOOK) and [S02]/[Ar] 0-5.10 could the unimolecular dissociation SO2 -> SO + O be observed in shock waves. At lower temperatures and higher [S02]/[Ar] secondary bimolecular reactions were obviously important a complex mechanism is evident, but cannot yet be uniquely resolved. An exceptionally high rate is reported for the reverse reaction O -1- SO SO2 = [Ar] 3-2 x lO cm mol" s- = [Ar]. 8-7 x... 

Dissociation of formaldehyde, CHgO, at comparably low temperatures is obviously determined by a complex decomposition mechanism. Conclusions on the unimolecular dissociation can only be drawn from measurements at high temperatures under shock wave conditions. In this system the primary dissociation leading to formyl radicals is followed by decomposition of CHO and subsequent reactions of H atoms with CH2O and CHO. By analysing the chain mechanism the rate constant of the unimolecular reaction was derived. ... 

An important additional restriction on flame structure studies of kinetics is provided by the practical problem of maintaining one dimensional flame stability over a wide range of compositions, which limits the ranges of fuel/oxidizer ratios and percentage dilution by inert additives accessible to experimental study. The advantages to the kineticist of freedom in the selection of these quantities has been stressed above. The choice of experimental conditions in flames is also limited by the direct relationship between flame temperature and initial composition. In the shock tube where heating is provided by an outside source, i.e., the shock wave, these two variables can be selected independently of one another. The instability problem with exothermic reactions in shock waves is of a different character from that in flames. 

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