A Shock Tube Utilized to Produce Sharprising Overpressures of 400 Milliseconds Duration and Its Employment in Biomedical Experimentation

Abstract

FORWORDThe purpose of the present study is two-fold; namely, (1) to describe "long-duration" pressure pulses simulating those produced by nuclear explosions, and (2) to present the result of an interspecies animal study when the data on six different animals are extrapolated to a biologic target the size of man.The results are limited to single-pulses of overpressure which rise almost instantaneously to a maximum and endure for about 400 msec.As far as man is concerned, these results do not apply to very short duration overpressures (50 msec or less), to pressures having a slow or step-wise rise to a maximum, and to oscillating pressures of considerable magnitude.Also the data apply to overpressure injury under circumstances in which displacement from blast pressures and winds is minimized and blast-energized missiles do not occur.The findings are applicable to military and industrial situations involving potential exposure to explosive phenomena, e.g., nuclear weapons, high explosives, tanks containing gases or liquids under high pressure, etc.The interspecies study is a part of research carried on since 1952 aimed at better understanding human response to the several environmental variations produced by low and high yield explosives.

The Overpressure-Duration Relationship and Lethality in Small Animals

“…The results, when added to those from previous shock-tube investigations 4 1 5, 6, would establish the pressure-duration relationship and lethality for those small-animal species.…”

“…For instance, with sharp-rising pressures of Z-to 3-msec duration, man's tolerance, in terms of overpressure required to produce 50-percent lethality (LD50), was calculated to be between 370 and 470 psi 3 . In contrast, when lethality data, compiled with a 400-msec pulse, were extrapolated to man, an LD5O of near 50 psi was obtained 4 . Obviously, there is a need for data on the response of animals to overpressure as a function of duration.…”

“…In most instances, there was little or no difference between lethality at 1 hour and 24 hours; consequently, only the 2 4 -hour mortality will be referred to throughout the remainder of this report.…”

Glyburide-Novel Prophylaxis and Effective Treatment for Traumatic Brain Injury

“…Animals with lethal dcBI died rapidly of cardiopulmonary arrest following prolonged apnea. By comparison, whole-body exposure of rats to blast is associated with an LD 50 that is 2 times smaller, 250 kPa (Richmond et al, 1961(Richmond et al, , 1962. The reason for the apparent twofold difference in sensitivity associated with cranium-only exposure compared to whole-body exposure is not known, but numerous factors could potentially contribute.…”

Numerical investigation of the effects of shock tube geometry on the propagation of an ideal blast wave profile

“…In particular, those tubes used to reproduce BOP waves for the study of biological damage are usually designated as biological shock tubes (BSTs) [12], which include compression-driven and blast-driven designs. Compressiondriven shock tubes [2,8,[10][11][12][13]16] avoid the safety concerns related to the storage and handling of high explosives and reduce the cost of test facilities to maintain, but they often fail to accurately represent the Friedlander waveform of freefield blast waves [5,6]. Blast-driven shock tubes [14,15,17] Fig.…”