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PubMed1990

A scientific paradox--explosives that are safe for use in flammable atmospheres.

Explosives used in coal mines have to be efficient in blasting rock and coal but at the same time should not ignite the flammable atmosphere that can sometimes be encountered underground. When used, the explosives are placed in drilled holes and shot in rounds, with a short delay between each shot. Because the explosive is of low power, later shots in the round may fail to detonate but deflagrate instead. Any flammable atmosphere that might be present would then be ignited. This paper describes investigations of the initiation and propagation of detonation in low-power mining explosives. Qualitative studies show how detonation can fail in the vicinity of delay detonators when the explosive is precompressed prior to detonation. Analysis of X-ray photographs of detonation waves propagating in conditions near to failure enables estimates to be made of reaction-zone shapes, densities, pressures, and particle velocities. This information is used to devise a model of the reaction-zone processes, explain why compression of the explosive can lead to detonation failure, and to assess nearness to failure.

Coal Mining↗
PubMed1997

Enhancement of the molecular ion yield in plasma desorption mass spectrometry using explosive matrices.

The working hypothesis of this study was that the chemical energy of matrix material may be released, although only on a microscale, under MeV ion bombardment and may assist ejection of large intact bioorganic molecules. To test the hypothesis, the performance of several common explosives, as matrices in plasma desorption mass spectrometry, was compared to the standard matrix, nitrocellulose (NC), which is also a high explosive. Two explosives, RDX and HMX, were found to be new, effective matrices for peptides and proteins. While the performance of RDX was comparable with that of nitrocellulose, HMX gave a superior molecular ion yield and a higher average charge state of desorbed molecular ions compared with NC. Noth RDX and HMX have a similar chemical composition and structure, although the latter is a more powerful explosive. The measured total ion yield allows the conclusion that the increase in the amount of ejected material, due to the chemical energy release in high explosives under MeV ion bombardment, is limited, perhaps to a factor of 2 to 3. The fact that not all tested explosives gave molecular ions from peptides and proteins suggests that other factors, such as gas-phase chemistry, may play a significant role in molecular ion formation.

Animals↗
PubMed1999

Environmental behavior of explosives in groundwater from the Milan Army Ammunition Plant in aquatic and wetland plant treatments. Removal, mass balances and fate in groundwater of TNT and RDX.

Phytoremediation of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in groundwater using constructed wetlands is a potentially economical remediation alternative. To evaluate Explosives removal and fate was evaluated using hydroponic batch incubations of plant and substrate treatments with explosives-contaminated groundwater amended with [U-14C]-TNT or [U-14C]-RDX. Plants and substrates were collected from a small-scale wetland constructed for explosives removal, and groundwater originated from a local aquifer at the Milan Army Ammunition Plant. The study surveyed three aquatic, four wetland plant species and two substrates in independent incubations of 7 days with TNT and 13 days with RDX. Parent compounds and transformation products were followed using 14C and chemical (HPLC) analyses. Mass balance of water, plants, substrates and air was determined. It was demonstrated that TNT disappeared completely from groundwater incubated with plants, although growth of most plants except parrot-feather was low in groundwater amended to contain 1.6 to 3.4 mg TNT L-1. Highest specific removal rates were found in submersed plants in water star-grass and in all emergent plants except wool-grass. TNT declined less with substrates, and least in controls without plants. Radiolabel was present in all plants after incubation. Mineralization to 14CO2 was very low, and evolution into 14C-volatile organics negligible. RDX disappeared less rapidly than TNT from groundwater. Growth of submersed plants was normal, but that of emergent plants reduced in groundwater amended to contain 1.5 mg RDX L-1. Highest specific RDX removal rates were found in submersed plants in elodea, and in emergent plants in reed canary grass. RDX failed to disappear with substrates. Mineralization to 14CO2 was low, but relatively higher than in the TNT experiment. Evolution into 14C-volatile organics was negligible. Important considerations for using certain aquatic and wetland plants in constructed wetlands aimed at removing explosives from water are: (1) plant persistence at the explosives level to which it is exposed, (2) specific plant-mass based explosives removal rates, (3) plant productivity, and (4) fate of parent compounds and transformation products in water, plants, and sediments.

Environmental Pollution↗
PubMed1998

Pretreatment for cellulose hydrolysis by carbon dioxide explosion

Cellulosic materials were treated with supercritical carbon dioxide to increase the reactivity of cellulose, thereby to enhance the rate and the extent of cellulose hydrolysis. In this pretreatment process, the cellulosic materials such as Avicel, recycled paper mix, sugarcane bagasse and the repulping waste of recycled paper are placed in a reactor under pressurized carbon dioxide at 35 degreesC for a controlled time period. Upon an explosive release of the carbon dioxide pressure, the disruption of the cellulosic structure increases the accessible surface area of the cellulosic substrate to enzymatic hydrolysis. Results indicate that supercritical carbon dioxide is effective for pretreatment of cellulose. An increase in pressure facilitates the faster penetration of carbon dioxide molecules into the crystalline structures, thus more glucose is produced from cellulosic materials after the explosion as compared to those without the pretreatment. This explosion pretreatment enhances the rate of cellulosic material hydrolysis as well as increases glucose yield by as much as 50%. Results from the simultaneous saccharification and fermentation tests also show the increase in the available carbon source from the cellulosic materials for fermentation to produce ethanol. As an alternative method, this supercritical carbon dioxide explosion has a possibility to reduce expense compared with ammonia explosion, and since it is operated at the low temperature, it will not cause degradation of sugars such as those treated with steam explosion due to the high-temperature involved.

Journal Article↗
PubMed2000

Comparison of Transient Network Brightenings and Explosive Events in the Solar Transition Region.

The relation between transient network brightenings, known as blinkers, and explosive events is examined based on coordinated quiet Sun observations in the transition region line O v lambda630 recorded by the Coronal Diagnostic Spectrometer (CDS), in the transition region line Si iv lambda1402 recorded by the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) instrument, and in photospheric magnetograms taken by the Big Bear Solar Observatory videomagnetograph. From these observations, we find that (1) explosive events, which are traditionally defined as features with very broad UV line profiles, tend to keep away from the centers of network brightenings and are mostly located at the edges of such brightenings, (2) CDS blinkers consist of many small-scale, short-lived SUMER "unit brightening events" with a size of a few arcseconds and a lifetime of a few minutes, and most importantly (3) each SUMER unit brightening event is characterized by a UV line profile that is not as broad as those of explosive events, but still has significantly enhanced wings. Our results imply that, like explosive events, individual unit brightening events involve high velocities, and, hence, blinkers may have the same physical origin as explosive events. It is likely that transient network brightenings and explosive events are both due to magnetic reconnection-but with different magnetic geometries.

Journal Article↗
PubMed2002

Explosive events on the Sun.

I describe two of the most dynamic and highly energetic phenomena in the Solar System--the explosive flares that can occur when plasma is confined by magnetic fields and the large-scale ejections of material known as 'coronal mass ejections'. These explosive events are poorly understood and yet occur in a variety of contexts in the Universe, ranging from planetary magnetospheres to active galactic nuclei. Understanding why flares and coronal mass ejections occur is a major goal across a wide range of space physics and astrophysics. Although explosive events from the Sun have dramatic effects on Earth, flares in other stars, for example, can be vastly more energetic and have an even more profound effect on their environment. We are now in the unprecedented position of having access to a number of space observatories dedicated to the Sun: the Yohkoh spacecraft, the Solar and Heliospheric Observatory, the Transition Region and Coronal Explorer and the Ramaty High Energy Solar Spectroscopic Imager. These cover a wide wavelength range from white light to gamma rays with both spectroscopy and imaging, and allow huge progress to be made in understanding the processes involved in such large explosions. The high-resolution data show dramatic and complex explosions of material on all spatial scales on the Sun. They have revealed that the Sun is constantly changing everywhere on its surface--something that was never imagined before. One of the mechanisms that has been proposed to account for the large energy release is magnetic reconnection. Recent observations from space increasingly support this view. This article will discuss those observations that support this model and also those that suggest different processes. The current space missions have given us an excellent insight into the actual explosive processes in the Sun. However, they have provided us with only a tantalizing glimpse of what causes the elusive trigger. Future missions such as Solar-B (the follow-on to Yohkoh), the Solar Terrestrial Relations Observatory, the Solar Dynamics Observatory and the Solar Orbiter mission will allow us to probe the trigger in a way that was not dreamt of a decade ago, by providing stereo views, measurements from Sun-grazing orbit, and much higher spatial, temporal and spectral resolution. It is an exciting time for solar physics and everything that we learn about the Sun will improve our ability to understand other magnetic phenomena in the Universe.

Journal Article↗
PubMed1999

Recognition and treatment of DSM-IV intermittent explosive disorder.

Although models of impulsive aggression are often associated with psychiatric disorders, some individuals demonstrate violent outbursts of rage that are variously referred to in the field as rage attacks, anger attacks, episodic dyscontrol, and intermittent explosive disorder. According to DSM-IV, intermittent explosive disorder is characterized by discrete episodes of failure to resist aggressive impulses resulting in serious assaults or destruction of property. Virtually no research has been done on intermittent explosive disorder as defined by DSM-IV criteria, and this article discusses the phenomenology, comorbidity, and treatment response of 27 individuals who met the DSM-IV criteria for the disorder. The association of the explosive episodes in these subjects with maniclike affective symptoms, the high rate of lifetime comorbid bipolar disorder, and the favorable response of explosive episodes to mood-stabilizing drugs suggest that intermittent explosive disorder may be linked to bipolar disorder.

Adolescent↗
PubMed2003

[Real time diagnostics of instantaneous temperature of combustion and explosion process by modern spectroscopy].

The combustion temperature is one of the important parameters to express flame combustion and explosion characteristics. It will effectively guide the design and manufacture of new model explosives, industrial explosive materials, and weapons. The recent developments and applications of real time diagnostics of instantaneous temperature of combustion and explosion processes by modern spectroscopic methods, such as atomic absorption-emission method, atomic emission two-line spectroscopy, atomic emission multiline spectroscopy, molecular rotation-vibration spectroscopy, coherent anti-stokes Raman scattering (CARS) and plane laser-induced fluorescence (PLIF), were reviewed in this paper. The maximum time resolution of atomic absorption-emission method is 25 microseconds. The time resolution of atomic emission two-line spectroscopy can reach 0.1 microsecond. These two methods can completely suit the need of real time and instantaneous temperature diagnostics of violent explosion and flame combustion. Other methods will also provide new effective research methods for the processes and characteristics of combustion, flame and explosion.

English Abstract↗
PubMed1983

Micro-explosion cystolithotripsy.

According to the newly established method of micro-explosion lithotripsy, a cystolithotriptor with an explosive catheter, the tip of which was charged with 5 mg. lead azide explosives, was developed. In 3 clinical cases bladder stones from 32 to 65 mm. in diameter were crushed successfully into several fragments by 1 to 8 explosions using the cystolithotriptor. The fragments then were smashed into grains with Young's cystoscope and washed out by aspiration. This success may prove the usefulness of micro-explosion lithotripsy, which also may be introduced for the treatment of calculi in other organs in the future.

Adult↗
PubMed1998

A novel source of carbon monoxide poisoning: explosives used in construction.

We describe an incident of carbon monoxide (CO) poisoning caused by CO migrating through soil after nearby detonation of explosive charges. Employees worked in a newly installed, unconnected manhole without incident and finished shortly before underground explosives were detonated 50 feet south of the manhole to break up rock and soil. A worker entering the manhole 45 minutes after the explosion collapsed within minutes, as did two coworkers who rescued him. One worker died, and all had elevated levels of carboxyhemoglobin. Air samples collected from the manhole 2 days after the incident showed 1,910 ppm CO; in laboratory detonations, sample explosive yielded 27 L CO per kilogram detonated. We believe the CO in this incident was released from the nearby explosion and migrated through soil and fractured rock into the manhole. The blasting and construction industries should be made aware of this previously unrecognized route of CO exposure. Additionally, confined-space procedures and training are needed to prevent future accidents.

Accidents, Occupational↗
PubMed2000

Developments in vapour cloud explosion blast modeling.

TNT Equivalency methods are widely used for vapour cloud explosion blast modeling. Presently, however, other types of models are available which do not have the fundamental objections TNT Equivalency models have. TNO Multi-Energy method is increasingly accepted as a more reasonable alternative to be used as a simple and practical method. Computer codes based on computational fluid dynamics (CFD) like AutoReaGas, developed by TNO and Century Dynamics, could be used also in case a more rigorous analysis is required. Application of the Multi-Energy method requires knowledge of two parameters describing the explosion: a charge size and a charge strength. During the last years, research has led to an improved determination of the charge strength (i.e., the class number or source overpressure) to be chosen to apply the blast charts. A correlation has been derived relating the charge strength to a set of parameters describing the boundary conditions of the flammable cloud and the fuel in the cloud. A simple approach may not be satisfactory in all situations. The overpressure distribution inside a vapour cloud explosion is generally not homogeneous and the presence of obstructions causes directional blast propagation in the near field. A CFD approach, in which the actual situation is modeled, supplies case-specific results. An overview of the key aspects relevant to the application of the Multi-Energy method and CFD modeling is provided. Then the application of the two methods is demonstrated for an example problem involving the calculation of the explosion blast load on a structure at some distance from the explosion in an offshore platform complex.

Air Pollution↗
PubMed2002

The digital radiographic and computed tomography imaging of two types of explosive devices.

Two well-established medical imaging methods, digital radiography (DR) and computed tomography (CT), were employed to obtain images of two types of explosive devices, model rocket engines and shotgun shells. The images were evaluated from an airport security perspective. In terms of geometrical shape, the detection probability of the explosive devices appears to be higher with DR imaging, but in terms of the actual explosive compounds in the devices, CT appears to offer a higher detection probability. DR imaging offers a low detection probability for the explosive powder in the shotgun shells, but a rather significant detection probability for the explosive propellant in the model rocket engines.

Explosions↗
PubMedDate not supplied

Preliminary investigation into the recovery of explosives from hair.

Sampling of hair has proved to be a useful non-invasive method for detecting illicit drugs. This study examined the viability of hair as a surface from which explosive traces can be recovered and showed that as little as one-hour vapour exposure can result in measurable traces of explosives. Contamination of the hair may result from direct contact with explosive particles or from secondary contact by hand. Also the paper demonstrates that hair can concentrate explosive from the ambient vapour of a variety of military explosives. It was found that the amount of TNT picked up by the hair increased with time of vapour exposure. The data also suggested that unwashed hair may pick up more TNT than washed hair.

Air Pollutants↗
PubMed2001

Degradation of explosives by nitrate ester reductases.

Explosive-contaminated land poses a hazard both to the environment and to human health. Microbial enzymes, either in their native or heterologous hosts, are a powerful and low-cost tool for eliminating this environmental hazard. As many explosives have only been present in the environment for 10 years, and with similar molecules not known in Nature, the origin of enzymes specialized for the breakdown of explosives is of particular interest. Screening of environmental isolates resulted in the discovery of flavoproteins capable of denitrating the explosives pentaerythritol tetranitrate (PETN) and glycerol trinitrate. These nitrate ester reductases are related in sequence and structure to Old Yellow Enzyme from Saccharomyces carlsbergenisis. All the members of this family have alpha/beta barrel structures and FMN as a prosthetic group, and reduce various electrophilic substrates. The nitrate ester reductases are, however, unusual in that they display activity towards the highly recalcitrant, aromatic explosive 2,4,6-trinitrotoluene, via a reductive pathway resulting in nitrogen liberation. We have embarked on a detailed study of the structure and mechanism of PETN reductase from a strain of Enterobacter cloacae. Work is focused currently on relating structure and function within this growing family of enzymes, with a view to engineering novel enzymes exhibiting useful characteristics.

Biodegradation, Environmental↗
PubMed1980

Burns due to grain dust explosions.

Dust explosions occurring in grain elevator storage and processing operations are increasing in frequency and are a world-wide source of injury and fatality. Despite extensive investigation by both private and governmental interests, the causes of most grain dust explosions remain a mystery. A number of methods to help prevent such explosions have been developed, but none has gained uniform acceptance. Despite a brief contact with flame in the flash of a dust cloud ignition, temperatures may exceed 1,000 degrees F and can cause severe burns. A single burn center's experience with eight patients injured in three separate grain elevator dust explosions during a 12-month period highlights the potential seriousness of the problem. Physicians practicing in grain producing or shipping areas of the world should be aware of the potential hazard imposed by grain storage operations. Prevention of these explosions by mandatory dust control systems and appropriate safety regulations is emphasized.

Adolescent↗
PubMed1996

Blast injuries: bus versus open-air bombings--a comparative study of injuries in survivors of open-air versus confined-space explosions.

OBJECTIVES: To compare injury patterns resulting from explosions in the open air versus within confined spaces. METHODS: Medical charts of 297 victims of four bombing events were analyzed. Two explosions occurred in the open air and two inside buses. Similar explosive devices were applied in all four incidents. The incidence of primary blast injuries, significant penetrating trauma (Abbreviated Injury Scale score > or = 2), burns, Injury Severity Score, Revised Trauma Score, and mortality were compared between the two populations. RESULTS: A total of 204 casualties were involved in open-air bombings, 15 of whom died (7.8%). Ninety-three victims were involved in bus bombings, 46 of whom died (49%). The difference in mortality rate was highly significant, p < 0.00001. Primary blast injuries were observed in 25 and 31 victims (34.2% and 77.5% of admitted victims), respectively (p = 0.00003). Median Injury Severity Score was 4 versus 18, respectively (p < 0.0001). CONCLUSION: Explosions in confined spaces are associated with a higher incidence of primary blast injuries, with more severe injuries and with a higher mortality rate in comparison with explosions in the open air.

Adolescent↗
PubMed2002

Pacemaker explosions in crematoria: problems and possible solutions.

The number of artificial cardiac pacemakers is increasing, as is the number of bodies being cremated. Because of the explosive potential of pacemakers when heated, a statutory question on the cremation form asks whether the deceased has a pacemaker and if so whether it has been removed. We sent a questionnaire to all the crematoria in the UK enquiring about the frequency, consequences and prevention of pacemaker explosions. We found that about half of all crematoria in the UK experience pacemaker explosions, that pacemaker explosions may cause structural damage and injury and that most crematoria staff are unaware of the explosive potential of implantable cardiac defibrillators. Crematoria staff rely on the accurate completion of cremation forms, and doctors who sign cremation forms have a legal obligation to provide such information.

Explosions↗
PubMed1991

[Explosion accidents during work with tires and wheel rims].

The object of this work is to draw attention to injuries resulting from explosions caused by work with wheel rims and tyres, the extent of the problem and the safety rules which already exist. Seven illustrative cases are presented. A not inconsiderable but frequently disregarded risk for accidental explosions is present in connection with pumping tyres and repairs of tyres and wheel rims. During the explosions, pressure waves of enormous violence may frequently be released. In connection with four accidental explosions of this type, a total of seven persons were injured. Four of these sustained life-threatening injuries. On the basis of the serious accidents, the authors consider it important to draw attention to the fact that the rules, which exist already and which are aimed primarily at avoiding and possibly limiting the extent of the violent explosive energy, should be brought to the notice of all who work with tyres and wheel rims.

Accidents, Occupational↗