Download or read book Blast Overpressure Studies Part II Nonauditory Damage Risk Assessment for Simulated Weapons Fired 100 Times from an Enclosure written by Barbara Merickel and published by . This book was released on 1997 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Anesthetized sheep were exposed to a reverberant wave environment like that produced from firing an antitank weapon from a room. The simulation was accomplished by detonating C4 explosives outside a chamber of 18.2 m3 volume. The blast wave traveled into the chamber through a 20-cm I.D. tube and was reflected off the back wall and subsequently throughout the chamber. The resulting waveform very closely approximated that generated by a Carl-Gustav antitank weapon fired from a chamber. Part I of the studies indicated that for a series of 1 shot or 3 shots, 2.5 minutes apart, multiple shots have a strong additive effect, decreasing the subthreshold levels. The subthreshold for a single blast was estimated to be above a peak of 48 kPa. The subthreshold for 3 exposures was estimated to be at 44 kPa. This study, called Part II, used 100 shots, 1 minute apart. For this exposure, a subthreshold peak of at least 23 kPa was verified using 19 animals.

Download or read book Blast Overpressure Studies Nonauditory Damage Risk Assessment for Simulated Muzzle Blast from a L2Omm Ml2l Mortar System written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study was undertaken to establish the subthreshold, threshold, and suprathresholds for nonauditory injuries in a simulated muzzle blast environment like that produced when firing a 120mm M121 mortar system. A vertical axis explosively driven shock tube, in combination with reflector shields, was used to produce the required muzzle blast pressure-time pattern. Varying numbers of anesthetized sheep were subjected to 6 or 50 blasts of simulated muzzle blast waves in 1.5- to 3.0-dB increments. The results of the study demonstrated that sheep could be exposed to Pmax levels consisting of 6 blasts of 36 kPa each and 50 blasts of 30 kPa each and sustain no injuries to trivial upper respiratory tract injuries at most. Threshold injuries were calculated to occur at 53 and 34 kPa for 6- and 50-blast exposures, respectively. Suprathresholds for URT and GI tract lesions were predicted to be 69 and 46 kPa for 6 and 50 blasts each. A suprathreshold for lung hemorrhage was predicted at 277 kPa for 6 exposures. Comparative analyses of this study with previous complex wave studies demonstrated that the safe nonauditory subthreshold for as many as 100 complex blastwave exposures was 22 kPa.

Download or read book Blast Overpressure Studies with Animals and Man Nonauditory Damage Risk Assessment for Simulated 155mm Self Propelled Howitzer Blast written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study was undertaken to establish the nonauditory injury subthreshold in a simulated muzzle blast environment like that produced when tiring an M109 155 mm self-propelled howitzer (SPH) with one or more hatches open. An explosively driven shock tube, the hull of an M108 SPH, and a six-plate reflector system were used to produce the required muzzle blast signature. Using as many as 40 anesthetized sheep for each exposure condition, safe no-injury levels were established with an occasional minor upper respiratory tract lesion. These levels were 24 kPa for 6 blasts and 20 kPa for 25 to 100 blasts.

Download or read book Medical Response to Terrorism written by Daniel C. Keyes and published by Lippincott Williams & Wilkins. This book was released on 2005 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive reference provides all the information emergency departments and personnel need to prepare for and respond to terrorist events. The first section covers all agents potentially used in terrorist attacks—chemical, biologic, toxicologic, nuclear, and explosive—in a systematic format that includes background, triage, decontamination, signs and symptoms, medical management, personnel protection, and guidelines for notifying public health networks. Algorithms show when to suspect and how to recognize exposure and detail signs and symptoms and management protocols. The second section focuses on all-hazards preparedness for hospitals, communities, emergency medical services, and the media, and includes an important chapter on simulation of disasters.

Download or read book Modeling of the Non Auditory Response to Blast Overpressure The State of Modeling Blast Injury written by and published by . This book was released on 1990 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: To understand the importance of the findings of the modeling project and to appreciate the need for extending those ideas, it is necessary to review the state of knowledge of blast overpressure injury at the time that the modeling project was initiated and how the needs of Army have evolved. In the early 1980's, two methods existed for assessing blast overpressure injury: one, Military Standard 1474B (Ref. 1), for use in occupational situations, and the other, the Bowen curves (Ref. 2), for use in combat conditions. Mil. Std. 1474-B is a standard developed for predicting auditory hazard based on observed values of peak pressure level and duration. It contains the so-called 'Z-line, ' above which no soldier should be exposed because of possible nonauditory injury that no amount of hearing protection could prevent. The nature of that injury is unspecified and the curve was not based on any observational data, although it might have reflected the intuition of the committee. The other curves in the standard were based primarily on small calibre weapons and, at the time of its creation, the Z-line was well removed from any operational weapon system.

Download or read book Blast Overpressure Studies with Animals and Man Task Order 1 Firing from a Bunker Simulator Study Task Order 4 Nonlinear Plug Study written by and published by . This book was released on 1996 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: To satisfy the Army's need for realistic safe limits for heavy weapon noise while wearing hearing protection, a 2-1/2 year study was undertaken. Using active duty military volunteers, 64 subjects established that the auditory system could be adequately protected with the RACAL(registered) muff from one to three exposures of the reverberant waveforms obtained from a rocket launcher out of an enclosure. Thus, nonauditory considerations set the exposure limits for this type of waveform. This research was accomplished under Task Order 1. Using 27 subjects, two types of nonlinear (increasing attenuation with level) plugs type of hearing protection were evaluated using 6 to 100 exposures of a freefield waveform of 1.5-ms duration. With the limited number of subjects, neither plug was proven adequate to protect the auditory system from this type of waveform. Several subjects had a temporary threshold shift (TTS) of their hearing of more than 25 dB. The compressible foam plug, did appear to provide adequate protection up the auditory limits for this waveform. This research was accomplished under Task Order 4.

Download or read book Modeling of the Non Auditory Response to Blast Overpressure Considerations in Developing a Mechanistically Based Model of Blast Induced Injury to Air Containing Organs written by and published by . This book was released on 1990 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to anticipate the potential for injury in a wide variety of blast environments, without the excessive use of animal tests, it is necessary to develop a mechanistic understanding that can be used reliably. The process by which the blast wave produces injury is conceived to have the following intermediate steps. The external blast creates a pressure load distribution on the body that sets it in mechanical motion. That motion is transmitted through the body structure to the air-containing organs, where rapid distortions cause stresses within the organ tissue. The combination of stress and motion does work on the tissue and, when certain material limits are exceeded, results in injury. Multiple, isolated exposures lead to a nonlinear accumulation of damage. This paper discusses the non-organ-specific aspects of modeling this process and demonstrates that the general characteristics of injury observed in animal field tests can be explained. Injury to the larynx is used to make a quantitative validation and a simple-wave, multiple-short Damage-Risk Criterion (DRC) is developed. Keywords: RA 3, Non-auditory response, Blast overpressure, Protective equipment, Weapons effects(Biological), DRC, Larynx, Air-containing organs, Stress(Physiology).

Download or read book Blast Overpressure Studies written by Daniel L. Johnson and published by . This book was released on 1998-05-01 with total page 283 pages. Available in PDF, EPUB and Kindle. Book excerpt: To satisfy the Army's need for realistic safe limits for heavy weapons noise while wearing hearing protection, a 2-1/2 year study was undertaken. Using active duty military volunteers, 64 subjects established that the auditory system could be adequately protected with the RACAL muff from one to three exposures of the reverberant waveforms obtained from a rocket launcher out of an enclosure. Thus, nonauditory considerations set the exposure limits for this type of waveform. This research was accomplished under Task Order 1. Using 27 subjects, two types of nonlinear (increasing attenuation with level) hearing protection were evaluated using 6 to 100 exposures of a freefield waveform of 1.5-ms duration. With the limited number of subjects, neither plug was adequate to protect the auditory system from this type of waveform. Several subjects had a temporary threshold shift (TTS) of their hearing of more than 25 dB. The compressible foam plug did appear to provide adequate protection up to the auditory limits for this waveform. This research was accomplished under Task Order 4.

Download or read book Proposed New Procedure for Estimating Allowable Number of Rounds for Blast Overpressure Hazard Assessment written by James H. Patterson and published by . This book was released on 1997 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current procedures for health hazard assessment of weapons blast overpressure use criteria contained in MIL-STD-1474D These criteria are applied to the test data so that the single pressure-time signature which indicates the greatest hazard (worst case round) is used to derive the recommended firing restrictions for the system. This approach is conservative and probably overrestricts the use of the system. Since it is based on the worst case round, the rest of the test data are essentially ignored in the hazard assessment. A procedure to establish recommended firing limits using all of the data has been developed. The procedure is based on accumulating hazards over the test data set until the criterion value is reached. This establishes the allowable number of rounds. A maximum exposure level for the worst case round is retained to prevent injury from single round exposures. Two variations of the basic procedure are explored and numerical examples of each are presented. The procedure implemented using a proportional dose accumulation is recommended.

Download or read book Modeling of the Non Auditory Response to Blast Overpressure Use of Surrogate and Analytical Models to Understand the Parameters Controlling Blast Injury to the Gastro Intestinal Tract written by James H. Stuhmiller and published by . This book was released on 1990 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Previous experimental studies using excised, perfused rabbit intestine in a sealed water tank, have provided direct visual observation that air bubbles produce local, violent, intestinal wall motion when they collapse under blast loading and that injury directly correlates with those motions. Measurements of the pressure within the bubble was shown to correlate with the motion of the wall and with injury. It was speculated that this pressure is an indirect measure of the stress in the wall tissue and therefore could be a means of quantifying the injury process. An analytical model of the dynamics of a bubble within an elastic membrane has been developed. Surrogate models, using materials with properties similar to that of intestine wall, but arranged in simpler geometric configurations, have been used to collect data on the dynamic process. The model results are compared and discussed. Keywords: RA 3, Weapons effects(Biological), Non-auditory responses, Blast overpressure, Explosions, G.I. Tract, Blast injury. (JG).

Download or read book A Health Hazard Assessment for Blast Overpressure Exposures Subtitle Biological Response to Blast Overpressure A Summary of Modeling written by and published by . This book was released on 1996 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A soldier in training is exposed to a variety of blast sources that can adversely affect his auditory and nonauditory systems. While auditory standards have been formulated for many decades, knowledge about nonauditory effects of blast have not been captured in a criteria that can be applied to all circumstances. For the past 15 years, JAYCOR, working together with the Walter Reed Army Institute of Research, has been using modeling, simulation, and data analysis to determine the nature of injury in animal models, capture that understanding in physiologically correct mathematical models, and extend the findings to objective criteria that can be used to set exposure limits. This paper summarizes the accomplishments of that effort.

Download or read book Modeling of the Non Auditory Response to Blast Overpressure Summary of Blast Overpressure Field Data written by and published by . This book was released on 1990 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report is a compilation of blast overpressure field data taken at the Blast Overpressure Test Site in Albuquerque, New Mexico. The work was conducted under the direction of Dr. D.R. Richmond and a complete list of source documents is contained in the Reference section. Most of the field tests involved sheep placed in the blast environment. The purpose was to empirically correlate injury to blast wave parameters. This report summarizes the test data compiled to date, but is by no means all inclusive. Corresponding to each test are plots of the associated incident pressure field. The purpose of this report is to provide a convenient summary of these tests for use by all researchers. This report is organized into seven sections, each devoted to a different blast study. They are: Armored Personnel Carrier (APC); Bunker Summer Studies of 85, 86, 87; Double Peak; and Iso-Impulse. Within each section, a separate page describes each combination of charge type, charge weight, height of burst, and range. Keywords: RA 3, Weapons effects (Biological), Non-auditory responses, Blast overpressure, Explosions, Blast injuries, Field data, Tables(Data).

Download or read book Injury Assessment for Blast Overpressure Effects written by M.J. van der Horst and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling of the Non Auditory Response to Blast Overpressure written by James H. Stuhmiller and published by . This book was released on 1987 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this project is to develop mathematical models of the physical processes that cause blast injury so that the results of tests using animals in simple blast environments can be safely translated to estimating hazard to man exposed to blast both in the free field and within enclosures. The present project builds upon earlier work to develop models of the mechanics of the thorax and lung exposed to simple blast waves. The scope of activity has been expanded to include the lung, the gastro-intestinal track, the upper respiratory tract, and the tympanic organs. In addition, the work now addresses occupational and combat level exposures. This report covers the second year of the contract. A considerable amount of progress has been made in understanding the basic mechanisms of injury and in providing practical tools for the measurement and prediction of blast effects. Keywords: Blast overpressure, Injury, Modeling.

Download or read book A Health Hazard Assessment for Blast Overpressure Exposures Subtitle Use of Animal Test Data in the Development of a Human Auditory Hazard Criterion for Impulse Noise written by and published by . This book was released on 1998 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hearing loss and sensory cell loss data, obtained from 909 chinchillas exposed to one of 137 different impulse noise or blast wave exposure paradigms, were statistically analyzed. The objective was to extract relations between the effects of the exposure on the auditory system (effects metrics) and metrics used to characterize the blast wave exposure. Specifically the following two questions were asked: (a) What is the best indicator of the amount of hazard associated with an impulse noise exposure? (b) How does the hazard of an impulse noise exposure accumulate with increasing numbers of impulses? Two analytical approaches were used. Both approaches indicated that the P-weighting functions or one of its derivatives (P1-, P2- or R-weighting) best organized the effects metrics. Depending on the analytical approach, either an energy trading rule of 10 log10 N or 6 log10 N; where N is the number of impulses, best organized the data for N between 10 and 100. For exposures of between 1 and 10 impulses, a region of the parametric space that is of considerable practical significance, there is insufficient data to form any conclusions. For this region the limited data suggest that an energy trading rule i.e., 10 log N, does not work.

Download or read book A Health Hazard Assessment for Blast Overpressure Exposures Subtitle Blast Overpressure Research Program written by and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The advent of nuclear blast caused a renewed interest in blast research in the United States. Thus, was the beginning of the Blast Overpressure Program at Kirtland Air Force Base, New Mexico. From the early 1950's through 1997, research on the biomedical, biological and biophysical effects of blast and shock was conducted. During this time, data essential to the understanding of the broad and complex nature of the biological effects of blast overpressure and impulse noise were obtained.

Download or read book A Proposal to Build a Laboratory Blast Overpressure Test Simulator Subtitle The Development of a Water Jet Impactor written by J. H. Y. Yu and published by . This book was released on 1982 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to establish a damage risk criteria (DRC) on pulmonary and gastrointestinal injury for the operating crew who fire heavy artillery, direct information that links the critical blast overpressure parameters and the degree of injury is necessary. Although field tests can be performed to provide the data, they are not amenable to speedy post-mortem analyses and sophisticated instrumentation. A laboratory test facility that is capable of generating the equivalent blast overpressure signal would serve the purpose and greatly facilitate the test procedure. It would also help to provide an environment for systematic and controlled experiments to quantify the relationship between blast and injury. However, for various reasons, most conventional approaches in generating the blast overpressure or its equivalent were not suitable for a laboratory setting. The idea of using a jet impactor to generate the impact signal was conceived. This report summarized the process of the development of such an apparatus. The first part focuses on the proof of the principle and identification of key elements and parameters. The second part is mainly devoted to the design and development of the prototype system.