Secondary shock

Alpha blockers can be used in secondary shock due to any blood/ fluid loss accompanied by reflex vasoconstriction. 

Pressure-time histories caused by explosions may be nonuniform and subject to amplification because of secondary shocks and shock reflections. Current models can provide only one- or two-dimensional histories. Failure modes are typically permanent deformation (plastic deformation/buckling), stable cracking (leaking), and brittle failure. Table 2.3 (Theodore et al., 1989) describes expected damage estimates for humans, structural elements, and process equipment for particular overpressures. 

It was shown in [46] that T2 temperature behind the incident wave is not high enough to create conditions for self-ignition, but such conditions can be achieved near the 2 K surface by repeated compression of the mixture caused by the secondary shock wave reflected from the end waU of the adjacent tube, the condition 5 K behind the reflected wave is described by T 2 temperature and F52 pressure. They can be calculated from ... 

Explosives are commonly categorized as primary, secondary, or high explosives. Primary or initiator explosives are the most sensitive to heat, friction, impact, shock, and electrostatic energy. These have been studied in considerable detail because of the almost unique capabiUty, even when present in small quantities, to rapidly transform a low energy stimulus into a high intensity shock wave. 

Hydro projects, dams, bridges, naval equipment and any installations that aie prone to continuous shocks and vibrations also require their primary and secondary systems to have a better design and operational ability to withstand seismic effects or other ground/surface vibrations. No specific tests are presently prescribed for such applications. But response spectra can be established even for such locations and the primary and secondary systems analysed mathematically or laboratory tested. 

That this is not always the case should be expected. In fact, if it was not for heterogeneous localization of some flow phenomena, it would be very diflicult to initiate secondary explosives, or to effect shock-induced chemical reactions in solids. Heterogeneous shear deformation in metals has also been invoked as an explanation for a reduction in shear strength in shock compression as compared to quasi-isentropic loading. We present here a brief discussion of some aspects of heterogeneous deformation in shock-loaded solids. 

The adiabatic head that is actually available at the rotor discharge is equal to the theoretical head minus the head losses from the shock in the rotor, the incidence loss, the blade loadings and profile losses, the clearance between the rotor and the shroud, and the secondary losses encountered in the flow passage... 

Grounding. Grounding is another way to provide protection from electric shock however, it is nonnally a secondary protective measure. By grounding a tool or electrical system, a low-resistance patlr to tire earth Uirough a ground coimection or comiections is intentionally created. Wlien properly done, tliis patli offers sufficiently low resistance and lias sufficient current-cariy ing capacity to prevent the buildup of voltages that may result... 

With regard to the hazard concern from physical and mechanical handling, the expl nature of the materials can pose a special problem. For example, during pneumatic transfer of samples in fast neutron activation, the polyethylene vials containing the expl approach speeds of 15m/sec and come to rest against a metal stop at both irradiation and count stations. However at PicArsn (Ref 13), in over 1000 irradiations and pneumatic transfers with up to 2.3g of shock-resistant secondary expls such as TNT, HMX,... 

Temperature field behind the leading shock at different times obtained by the numerical simulations [21]. 1, transverse detonation 2, strong part of the leading shock (overdriven detonation) 3, weak part of the leading shock (inert) 4, induction zone 5, transverse shock 6, unreacted tail 7, primary unreacted pocket and 8, secondary unreacted pockets. (Courtesy of V. Gamezo.)... 

Very recently, a third hypothesis has been pubHshed. Morita and co-workers [47] have suggested that the rpoH mRNA secondary structure itself acts as a thermosensor. In the absence of heat stress, the rpoH mRNA is folded into a secondary structure that occludes the ribosome binding site and the initiation codon. Upon heat shock, this structure is unfolded allowing ribosome binding and enhanced synthesis. 

High explosives which detonate to produce shock waves. Materials which are easily detonated by mechanical or electrical stimuli are termed primary explosives . Those requiring an impinging shock wave to initiate them are secondary explosives . 

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