25 Matching Results

Search Results

Advanced search parameters have been applied.

BLAST BIOLOGY. Technical Progress Report

Description: Experimental data regarding the biologic consequences of exposure to several environmental variations associated with actual and simulated explosive detonations were reviewed. Blast biology is discussed relative to primary, secondary, tentiary, and miscellaneous blast effects as those attributable, respectively, to variations in environmental pressure, trauma from blast-produced missiles (both penetrating and nonpenetrating), the consequences of physical displacement of biological targets by blast-produced winds, and hazards due to ground shock, dust, and thermal phenomena not caused by thermal radiation per se. Primary blast effects were considered, noting physical-biophysical factors contributing to the observed pathophysiology. A simple hydrostatic model was utilized diagrammatically in pointing out possible etiologic mechanisms. The gross biologic response to single. "fast"-rising overpressures were described as was the tolerance of mice, rats, guinea pigs. and rabbits to "long"-duration pressure pulses rising "rapidly" in single and double steps. Data regarding biological response to "slowly" rising over-pressures of "long" duration are discussed. Attention was called to the similarities under certain circumstances between thoracic trauma from nonpenetrating missiles and that noted from air blast. The association between air emboli, increase in lung weight (hemorrhage and edema), and mortality was discussed. Data relevant to the clinical symptoms and therapy of blast injury are presented. The relation of blast hazards to nuclear explosions was assessed and one approach to predicting the maximal potential casualties from blast phenomena is presented making use of arbitrary and tentative criteria. (auth)
Date: September 18, 1959
Creator: White, C.S. & Richmond, D.R.
Partner: UNT Libraries Government Documents Department

A TENTATIVE ESTIMATION OF MAN'S TOLERANCE TO OVERPRESSURES FROM AIR BLAST. Technical Progress Report

Description: Tentative estimates of the sharp''-rising overpressures as a function of duration which represent a lethal hazard to the 70-kg animal 1, 50, and 99% of the time were presented. The predictions were based on interspecies correlations and extrapolations encompassing blast-tolerance data for six mammalian species. The tentative application of the data to indicate human blast tolerance was discussed and relevant uncertainties in the estimates were emphasized. It was also pointed out that biologic tolerance would be different for air-blast pulses having non-ideal wave forms frequently associated with various geometries of exposure. Selected pathophysiological information pertinent to the biological response following blast exposure was given; namely, survival time and selected postshot observations of dogs and goats. (auth)
Date: November 1, 1962
Creator: Richmond, D.R. & White, C.S.
Partner: UNT Libraries Government Documents Department

THE INTERNAL ENVIRONMENT OF UNDERGROUND STRUCTURES SUBJECTED TO NUCLEAR BLAST. II. EFFECTS ON MICE LOCATED IN HEAVY CONCRETE SHELTERS

Description: A cage containing 20 mice was placed in each of 12 underground shelters in an attempt to assess biologically the inside environment of the shelters. Two samples of 20 mice each acted as controls. The structures, of French and German design, were located at ranges between 840 ft and 4320 ft from Ground Zero. A nuclear device was exploded atop a 700-ft tower and had a yield of 43 kt. All but one group of mice were recovered on D + 2 days. Aside from two samples placed in unrealistic locations, all animals were alive at recovery. With one exception, the peak pressures in the chambers that contained mice were insignificant, ranging from a fraction of 1 psi to 1.6 psi. The one high pressure of 14.4 psi did not kill any of the mice. According to the film-badge dosimeters, one group of mice received 190 r of gamma radiation. The others were exposed to 54 r of gamma or less. The mice were observed for a 60-day postshot period. The deaths that occurred were attributed to a Salmonella infection in the animal colony and not to radiation. Although the gamma radiation doses that most of the animal groups received were low, the levels that existed in the main chambers near the entry doors of the German shelters were over 100 r, a biolog ically significant dose. In constrast, the environment within two of the French shelters appeared to be quite acceptable. (auth)
Date: September 1, 1959
Creator: Richmond, D.R.; White, C.S.; Sanchez, R.T. & Sherping, F.
Partner: UNT Libraries Government Documents Department

COMPARATIVE NUCLEAR EFFECTS OF BIOMEDICAL INTEREST

Description: Selected physical and biological data bearing upon the environmental variations created by nuclear explosions are presented. Emphasis is placed upon the early consequences of exposure to blast, thermal radiation, and ionizing radiation to elucidate the comparative ranges of the major effects as they vary with explosive yield and as they brief definitions of the terminology employed is followed by a section that utilizes text and tabular material to set forth events that follow nuclear explosions and the varied responses of exposed physical and biological materials. Finally, selected quantitative weapons-effects data in graphic and tabular form are presented over a wide range of explosive yields to show the relative distances from Ground Zero affected by significant levels of blast overpressures, thermal fluxes, and initial and residual penetrating ionizing radiations. However, only the early rather than the late effects of the latter are considered. 52 references. (auth)
Date: September 1, 1960
Creator: White, C.S.; Bowen, I.G.; Richmond, D.R. & Corsbie, R.L.
Partner: UNT Libraries Government Documents Department

THE ENVIRONMENTAL MEDICAL ASPECTS OF NUCLEAR BLAST. Technical Progress Report

Description: The nature of certain critical lesions seen after exposure to air blast is described. The early lethality characterizing primary and tertiary blast damage is emphasized along with the seriousness of injuries caused by blastenergized debris. Tentative criteria are developed to the end that different levels of environmental variations caused by blast phenomena could be quantitatively related to various levels of biological response. Using the free- field scaling laws and a mathematical model whereby translational velocities can be computed for animate and inanimate objects, the criteria are applied to nuclear explosions ranging in yield from 1 kt to 100 Mt. Thus, it is possible to specify, as a function of yield, the hazard ranges inside which various blast injuries might occur. At these ranges the associated levels of initial nuclear and thermal radiation were computed to allow at least some assessment of the relative importance of all the major hazards from nuclear detonations. (auth)
Date: November 1, 1962
Creator: White, C.S.; Bowen, I.G. & Richmond, D.R.
Partner: UNT Libraries Government Documents Department

THE OVERPRESSURE-DURATION RELATIONSHIP AND LETHALITY IN SMALL ANIMALS. Technical Progress Report

Description: A total of 993 mice, rats, guinea pigs, and rabbits were exposed to sharp-rising overpressures of various short durations. They were mounted on a concrete pad above which high-explosive charges, ranging in weight from 0.50 oz to 64 lbs, were detonated. Pressure-time measurements were obtained with pencil- type and shock-tube piezo-electric gauges on the pad directly beneath the charges. The duration of the blast waves ranged from 0.40 to 6.8 msec. The LD/sub 50/ pressures were calculated for each species at the different pulse durations. In general, the pressures required to produce 50% lethality rose at the shorter durations. Combining the results of this study with those from previous shock- tube investigations made it possible to define the tolerance of four small-animal species to sharply rising overpressures as a function of pulse duration. (auth)
Date: September 10, 1962
Creator: Richmond, D.R.; Goldizen, V.C.; Clare, V.R. & White, C.S.
Partner: UNT Libraries Government Documents Department

Comparative nuclear effects of biomedical interest. Civil effects study

Description: Selected physical and biological data bearing upon the environmental variations created by nuclear explosions are presented in simplified form. Emphasis is placed upon the ``early`` consequences of exposure to blast, thermal radiation, and ionizing radiation to elucidate the comparative ranges of the major effects as they vary with explosive yield and as they contribute to the total hazard to man. A section containing brief definitions of the terminology employed is followed by a section that utilizes text and tabular material to set forth events that follow nuclear explosions and the varied responses of exposed physical and biological materials. Finally, selected quantitative weapons-effects data in graphic and tabular form are presented over a wide range of explosive yields to show the relative distances from Ground Zero affected by significant levels of blast overpressures, thermal fluxes, and initial and residual penetrating ionizing radiations. However, only the ``early`` rather than the ``late`` effects of the latter are considered.
Date: January 12, 1961
Creator: White, C.S.; Bowen, I.G.; Richmond, D.R. & Corsbie, R.L.
Partner: UNT Libraries Government Documents Department

TERTIARY BLAST EFFECTS: THE EFFECTS OF IMPACT ON MICE, RATS, GUINEA PIGS AND RABBITS. Technical Progress Report

Description: A total of 455 mlce, rats, gulnea plgs, and rabbits was subjected to lmpact at velocitles ranglng between 25 ft/sec and 51 ft/sec. The deslred velocities were generated by allowlng the anlmals to free-fall from various helghts to a flat concrete pad. The ventral surface of each anlmal was the area of impact. Problt analyses of the 24-hr mortallty data ylelded LD/sub 50/ lmpact veloclties with 95% confldence limits as follows: mouse, 39.4 (37.4 to 42.0) ft/ sec; rat, ft/sec; and rabbit, 31.7 (30.2 to 33.3) ft/sec. The LD/sub 50/ figures for the mouse and rat were slgnificantly higher, statlstically, than those for the gulnea plg and rabblt. The small spread ln the LD/sub 50/ values suggested little variation ln the tolerance of blologlcal systems to impact. Further, the steepness of the mortallty curves lndicated a narrow survlval range to lmpact. Extrapolatlon of the experimental data to the 70 kg anlmal yielded a predicted LD/ sub 50/ impact velocity of 26 ft/sec (18 mph). Literature relevant to the human case was revlewed and the tentative appllcabllity of the predlcted flgures to adult man ls discussed. (auth)
Date: February 28, 1961
Creator: Richmond, D.R.; Bowen, I.G. & White, C.S.
Partner: UNT Libraries Government Documents Department

Biologic response to complex blast waves

Description: Small, bare charges were detonated inside an M59 armored personnel carrier (APC) in an attempt to simulate the complex blast waves generated by the jets from shaped-charge warheads penetrating into armored vehicles. Anesthetized sheep were placed inside the APC at 92- and 122-cm ranges from 57- or 113-g pentolite charges. Pressure-time was measured by pressure transducers either mounted on the animals or free standing at comparable ranges on the opposite side of the vehicle. In general, the waveforms were characterized by an initial shock wave of less than 1-msec duration followed by repeated reflections of decreasing magnitude. No deaths nor lung hemorrhages were observed, but all the animals sustained severe ear injury. Animals subjected to peak overpressures of 1.2 to 2.3 bar from the 113-g explosions also received slight non-auditory blast injuries to the upper respiratory and gastrointestinal tracts; those exposed to peak overpressures of just under 1 bar from the 57-g charges did not. The non-auditory blast injuries inside the APC were more severe than those sustained by sheep at comparable distances from 113-g charges in the open. The results suggested that the biological consequences of a complex wave of the type encountered in this study can be equated approximately to a Friedlander wave with a peak overpressure equal to that of the complex wave and with a total impulse equal to the impulse over the first 2 to 3 msec of the complex wave. 9 refs., 7 figs., 1 tab.
Date: January 1, 1985
Creator: Richmond, D.R.; Yelverton, J.T.; Fletcher, E.R. & Phillips, Y.Y.
Partner: UNT Libraries Government Documents Department

MISSILE STUDIES WITH A BIOLOGICAL TARGET

Description: Fourteen dogs located on the lee side of planted gravel, of a concrete- block wall, and of glass mounted in the open and in houses were exposed to the environmental variations associated with full-scale nuclear detonations. Aluminum foil was used to protect the animals from thermal effects. The missile environment was monitored through the use of quantitutive missile-trapping techniques. Pressure-time variations in the environment were also recorded. Biologic damage from overpressure and missiles was determined, and the associations between physical envtronmental factors and biologic response were noted and analyzed. The feasibility of utilizing ninssile data, along with other available information from the literature, as a means of quantitutively assesing biologic hazard was estublished by the close correspondence between observed and predicted dangerous wounds. This test provided full-scale validation of procedures and experimsnts worked out chiefly in the laboratory. (auth)
Date: April 1, 1960
Creator: Goldizen, V.C.; Richmond, D.R.; Chiffelle, T.L.; Bowen, I.G. & White, C.S.
Partner: UNT Libraries Government Documents Department

MORTALITY IN SMALL ANIMALS EXPOSED IN A SHOCK TUBE TO "SHARP"-RISING OVERPRESSURES OF 3-4 MSEC DURATION. Technical Progress Report

Description: A total of 661 animals was exposed to sharp''-rising overpressures of 3 to 4 msec duration using a shock tube of novel design which produced a pressure pulse similar to that obtained with high explosives. The reflected shock overpressures associated with 50% lethality were 29.0, rabbit, respectively. Other observations included the time of death in mortally wounded animals and gross pathological lesions likely to contribute to mortality. Selected data from the literature bearing upon the influence of overpressure and pulse duration on lethality were reviewed. These included pulse durations ranging from less than 1 msec to 8 sec. The critical pulse duration, that duration shorter than which the overpressures required for mortality increases sharply, was noted to depend upon animal size and to be of the order of many hundreds of microseconds to very few milliseconds for smaller'' animals and a few to many tens of milliseconds for larger'' animals. (auth)
Date: June 15, 1961
Creator: Richmond, D.R.; Goldizen, V.C.; Clare, V.R.; Pratt, D.R.; Sherping, F.; Sanchez, R.T. et al.
Partner: UNT Libraries Government Documents Department