Shock-induced synthesis

Along a different line of research on shock compression of solids, namely, recovery experiments, great progress was also being made. Shock-induced recovery-type chemical reactions in encapsulated samples were first reported by Riabinin in 1956. Shock-induced metallographic transformation and the observation of twin bands in iron were first reported by Smith in 1958. Another major breakthrough was the shock-induced synthesis of diamond in 1961 by DeCarli and Jamieson. 

Liepins R, Staudhammer KP, Johnson KA, Thomson M (1988) Shock-induced synthesis cubic boron-nitride from ammonia borane. Matter Lett 7 44 6... 

N.N. Thadhani, Shock-Induced Chemical Synthesis of Intermetallic Compounds, in Shock Compression of Condensed Matter—1989 (edited by S.C. Schmidt, J.N. Johnson, and L.W. Davison), Elsevier Science, Amsterdam, 1990, pp. 503-510. 

Thadhani, N.N., Shock-Induced Chemical Synthesis of Intermetallic Compounds, presented at the American Physical Society Topical Conference on Shock Compression of Condensed Matter, Albuquerque, NM, August 14-17, 1989. 

Fig. 8.1. Shock-induced solid state chemical synthesis of a zinc ferrite has been studied over a wide range of temperature and pressure. The figure shows the location of conditions for which the reaction has been studied.

Intermetallics also represent an ideal system for study of shock-induced solid state chemical synthesis processes. The materials are technologically important such that a large body of literature on their properties is available. Aluminides are a well known class of intermetallics, and nickel aluminides are of particular interest. Reactants of nickel and aluminum give a mixture with powders of significantly different shock impedances, which should lead to large differential particle velocities at constant pressure. Such localized motion should act to mix the reactants. The mixture also involves a low shock viscosity, deformable material, aluminum, with a harder, high shock viscosity material, nickel, which will not flow as well as the aluminum. 

The initial studies on nickel-aluminide synthesis defined a number of important issues in shock-induced solid state synthesis. This work was extended to the influence of powder particle morphology in recent work of Thadhani and... 

Shock-Induced Solid State Chemical Synthesis... 

This chapter presents detailed and thorough studies of chemical synthesis in three quite different chemical systems zinc ferrite, intermetallic, and metal oxide. In addition to different reaction types (oxide-oxide, metal-metal, and metal oxide), the systems have quite different heats of reaction. The oxide-oxide system has no heat of reaction, while the intermetallic has a significant, but modest, heat of reaction. The metal oxide system has a very large heat of reaction. The various observations appear to be consistent with the proposed conceptual models involving configuration, activation, mixing, and heating required to describe the mechanisms of shock-induced solid state chemistry. 

Cleget, M. Polla, B.S. (1990). Erythrophagocytosis induces heat shock protein synthesis by human monocytes-macrophages. Proc. Natl. Acad. Sci. USA 87, 1081-1085. 

Induction of heat-shock proteins depends upon a heat-shock promoter element (HSE) that binds an activating transcription factor HSF.452-455 An increase in temperature not only induces synthesis of heat-shock proteins but represses synthesis of most other proteins. Thus, in E. coli or Salmonella a shift from 30°C to 42°C causes the appearance of 13 heat-shock proteins. At 50°C synthesis of almost all other proteins stops. In E. coli transcription of heat-shock genes is controlled by alternative factors, o32 and oE.456 456a... 

Cold stress may induce synthesis of heat-shock (stress) proteins. Exposure of cells to cold shock may lead to the induction of one or more of the classes of molecular chaperones that also are induced by heat shock. This is strong evidence that low temperature, like high temperature, can lead to non-native protein structures in vivo and, therefore, to the requirement for enhanced chaperoning activity. Induction of cold-induced protein chaperones has been seen in bacteria (Salotra et al., 1995), in whole organism studies of ectothermic animals (Petersen et al., 1990 Yocum et ah, 1991),... 

Many borides can be synthesized by novel synthetic methods, inclnding shock-induced chemical reactions, mechanical alloying by ball milling, and self-propagating high-temperature synthesis. In these methods, intimately mixed elemental powders are brought to react by a rapid pressure increase, mechanical deformation including local... 

Thadani, N. N., Shock-induced chemical reactions and synthesis of materials. Prog. Mater. Sci., 37, 117(1993). 

In fact, a medley of substances (autacoids), kinins, prostaglandins, leukotrienes, histamine, endorphins, serotonin, vasopressin, has been implicated. In endotoxic shock, the toxin also induces synthesis of nitric oxide, the endogenous vasodilator, in several types of cells other than the endothelial cells which are normally its main source. 

On the other hand, some studies on shock-induced devolatilization produced results inconsistent wiOt the above conclusion. Mukliin et al. [70J examined tlie effect of laser-pulse heating on meteorite materials and silicates in order to simulate the vaporization that occurs during impacts and to stud the chemical composition of the gases produced. The experimental results showed tliat the residual gas mixture consisted of both oxidized and reduced components CO, CO2, SO2, H2O, H2, N2, H2S, COS, CS2, various hydrocarbons from Ci to Ce, HCN, and CH3CHO. They emphasized that the gas mixtures formed by vaporization of silicates provide favorable conditions for abiotic synthesis of organic materials. 

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