scholarly journals THE RELATIONSHIP BETWEEN SELECTED BLAST-WAVE PARAMETERS AND THE RESPONSE OF MAMMALS EXPOSED TO AIR BLAST

1968 ◽  
Vol 152 (1) ◽  
pp. 103-121 ◽  
Author(s):  
Donald R. Richmond ◽  
Edward G. Damon ◽  
E. Royce Fletcher ◽  
I. Gerald Bowen ◽  
Clayton S. White
1966 ◽  
Author(s):  
Donald R. Richmond ◽  
Edward G. Damon ◽  
E. R. Fletcher ◽  
I. G. Bowen ◽  
Clayton S. White

1981 ◽  
Vol 71 (6) ◽  
pp. 1731-1741
Author(s):  
I. N. Gupta ◽  
R. A. Hartenberger

Abstract An analysis of seismic field data from surface shots in two radically different geologic environments shows significantly different seismic phases at the two sites. At the first site, which has a layered sedimentary section, five distinct phases are observed: the P-wave first arrival; a complex wave train consisting of higher mode Rayleigh waves; a precursor to air-blast wave; the air blast wave; and the air-coupled Rayleigh waves. Records from the second site, overlying an unlayered mass of igneous rocks, show only three distinct seismic phases: the P-wave first arrival; a simple wave train of fundamental-mode Rayleigh and Love waves; and an air blast wave. Peak ground velocity, based on the average of the three largest amplitudes in the surface waves preceding the air blast wave, scales well with yield for both sites. Measurements of peak ground velocity may be used to estimate yields of explosive charges at either site within a factor of about 2 if the source distance is known. The scaling relationship appears to be valid over a wide range of yields and site geological conditions.


SLEEP ◽  
2021 ◽  
Author(s):  
Anne Richards ◽  
Sabra S Inslicht ◽  
Leslie M Yack ◽  
Thomas J Metzler ◽  
J Russell Huie ◽  
...  

Abstract Study Objectives Published research indicates that sleep is involved in emotional information processing. Using a fear-potentiated startle (FPS) and nap sleep protocol, we examined the relationship of emotional learning with REM sleep (REMS) in trauma-exposed participants. We also explored the roles of PTSD symptoms, biological sex, and an integrative measure of polysomnography-measured (PSG) sleep in the learning-sleep relationship. Methods After an adaptation nap, participants (N=46) completed 2 more visits (counterbalanced): a stress-condition visit, which included FPS conditioning procedures prior to a nap and assessment of learning retention and fear extinction training after the nap, and a control visit, which included a nap opportunity without stressful procedures. FPS conditioning included a “fear” visual stimulus paired with an air blast to the neck and a “safety” visual stimulus never paired with an air blast. Retention and extinction involved presentation of the visual stimuli without the air blast. Primary analyses examined the relationship between FPS responses pre- and post- sleep with stress-condition REMS duration, controlling for control-nap REMS duration. Results Higher safety learning predicted increased REMS and increased REMS predicted more rapid extinction learning. Similar relationships were observed with an integrative PSG sleep measure. They also showed unexpected effects of PTSD symptoms on learning and showed biological sex effects on learning-sleep relationships. Conclusions Findings support evidence of a relationship between adaptive emotional learning and REMS. They underscore the importance of examining sex effects in sleep-learning relationships. They introduce an integrative PSG sleep measure with potential relevance to studies of sleep and subjective and biological outcomes.


2020 ◽  
Vol 87 (5) ◽  
Author(s):  
Anthoni Giam ◽  
William Toh ◽  
Vincent Beng Chye Tan

Abstract The analysis of complex blast scenarios typically requires advanced computational methods such as multi-material Eulerian and coupled Eulerian–Lagrangian (CEL) analysis where Jones–Wilkins–Lee (JWL) equation of state is used to model the explosive material. While multiple sets of empirical JWL parameters for trinitrotoluene (TNT) explosives have been published over the past few decades, there is also a lack of guidelines and comparative studies on their applications for the blast analysis. A standardized description of the explosive material behavior allows for a better interpretation of results from research studies involving different blast scenarios and JWL parameters. In this paper, the authors utilize numerical finite element (FE) simulations to investigate the influence of different TNT JWL parameter sets on the blast wave characteristics of a free-air blast across different scaled distances. Utilizing multi-material Eulerian analysis, a series of spherical free-air blasts involving a 100-kg TNT charge modeled with different TNT JWL parameters are conducted. The blast wave characteristics including the incident overpressure, impulse, and time of arrival (TOA) are benchmarked against the empirical-based Kingery–Bulmash air blast formulations through the conventional weapon effect calculator conwep. It was found that the incident overpressure and impulse are highly sensitive to the JWL parameters, with differences as high as 40% at smaller scaled distances, while the influence on TOA is much less significant. This paper hopes to provide a guide for future users on the appropriate JWL parameter sets to model the air blast events involving TNT explosives.


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