SEARCH · PubMed Health

Results for “EXPLOSIONS”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources

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↗

PubMed2006

Characterization of high explosive particles using cluster secondary ion mass spectrometry.

The use of secondary ion mass spectrometry (SIMS) for the detection and spatially resolved analysis of individual high explosive particles is described. A C(8) (-) carbon cluster primary ion beam was used in a commercial SIMS instrument to analyze samples of high explosives dispersed as particles on silicon substrates. In comparison with monatomic primary ion bombardment, the carbon cluster primary ion beam was found to greatly enhance characteristic secondary ion signals from the explosive compounds while causing minimal beam-induced degradation. The resistance of these compounds to degradation under ion bombardment allows explosive particles to be analyzed under high primary ion dose bombardment (dynamic SIMS) conditions, facilitating the rapid acquisition of spatially resolved molecular information. The use of cluster SIMS combined with computer control of the sample stage position allows for the automated identification and counting of explosive particle distributions on silicon surfaces. This will be useful for characterizing the efficiency of transfer of particulates in trace explosive detection portal collectors and/or swipes utilized for ion mobility spectrometry applications.

Journal Article↗

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↗

PubMed2004

Detection and decontamination of residual energetics from ordnance and explosives scrap.

Extensive manufacturing of explosives in the last century has resulted in widespread contamination of soils and waters. Decommissioning and cleanup of these materials has also led to concerns about the explosive hazards associated with residual energetics still present on the surfaces of ordnance and explosives scrap. Typically, open burning or detonation is used to decontaminate ordinance and explosive scrap. Here the use of an anaerobic microbiological system applied as a bioslurry to decontaminate energetics from the surfaces of metal scrap is described. Decontamination of model metal scrap artificially contaminated with 2,4,6-trinitrotoluene and of decommissioned mortar rounds still containing explosives residue was examined. A portable ion mobility spectrometer was employed for the detection of residual explosives residues on the surfaces of the scrap. The mixed microbial populations of the bioslurries effectively decontaminated both the scrap and the mortar rounds. Use of the ion mobility spectrometer was an extremely sensitive field screening method for assessing decontamination and is a method by which minimally trained personnel can declare scrap clean with a high level of certainty.

Anaerobiosis↗

PubMed2004

Explosive radiations and the reliability of molecular clocks: island endemic radiations as a test case.

The reliability of molecular clocks has been questioned for several key evolutionary radiations on the basis that the clock might run fast in explosive radiations. Molecular date estimates for the radiations of metazoan phyla (the Cambrian explosion) and modern orders of mammals and birds are in many cases twice as old as the palaeontological evidence would suggest. Could some aspect of explosive radiations speed the molecular clock, making molecular date estimates too old? Here we use 19 independent instances of recent explosive radiations of island endemic taxa as a model system for testing the proposed influence of rapid adaptive radiation on the rate of molecular evolution. These radiations are often characterized by many of the potential mechanisms for fast rates in explosive radiations--such as small population size, elevated speciation rate, rapid rate of morphological change, release from previous ecological constraints, and adaptation to new niches--and represent a wide variety of species, islands, and genes. However, we find no evidence of a consistent increase in rates in island taxa compared to their mainland relatives, and therefore find no support for the hypothesis that the molecular clock runs fast in explosive radiations.

Adaptation, Biological↗

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↗

PubMed2007

Visual detection of trace nitroaromatic explosive residue using photoluminescent metallole-containing polymers.

The detection of trace explosives is important for forensic, military, and homeland security applications. Detection of widely used nitroaromatic explosives (trinitrotoluene [TNT], 2,4-dinitrotoluene [DNT], picric acid [PA]) was carried out using photoluminescent metallole-containing polymers. The method of detection is through the quenching of fluorescence of thin films of the polymer, prepared by spray coating organic solutions of the polymer, by the explosive analyte. Visual quenching of luminescence (lambda(em) approximately 400-510 nm) in the presence of the explosive is seen immediately upon illumination with near-UV light (lambda(ex)=360 nm). Detection limits were observed to be as low as 5 ng for TNT, 20 ng for DNT, and 5 ng for PA. In addition, experiments with normal production line explosives and their components show that this technology is also able to detect composition B, Pyrodex, and nitromethane. This method offers a convenient and sensitive method of detection of trace nitroaromatic explosive residue.

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↗

PubMed2002

Effect of seawater soaking on explosive cornea injury.

OBJECTIVE: To observe the changes in corneal tissue after explosive corneal injury and the effect of seawater soaking on the healing of cornea after explosive injury with the help of optical microscope. METHODS: Make 10 similar explosive injury models of rabbit's eyeball using 10 adult grey rabbits. For each rabbit, both eyes are artificially injured through explosion; its right eye is the comparison eye and after the injury the left eye is soaked in seawater for 30 minutes. (Conduct slit lamp examinations, fluorescein dyeing, and ultrasonic cornea thickness metering on the corneas at intervals, that is, before the injury, 1, 2, 3, 4, 5, 7, 9, 12, 15 days after the injury respectively. Examine the corneas under the optical microscope and make comparisons. RESULTS: The corneal thickness of the experiment eye becomes apparently thicker than that of the comparison eye after the injury. The corneal clouding of the former apparently aggravates compared with the latter. The healing of corneal epithelium in the injured eye is slower compared with that in the comparison eye. Comparative examination under the optical microscope shows: after the injury, the corneal tissue of the experiment eye changes distinctly, its healing is delayed and the vascularization degree becomes high in corneal stroma. CONCLUSION: Scars and vascularization of various degrees will appear in corneal stroma after explosive injuries. Seawater soaking will have bad effects on the healing of the cornea injured in explosions.

Animals↗

PubMed2004

Rapid screening of selected organic explosives by high performance liquid chromatography using reversed-phase monolithic columns.

This study presents the rapid screening of various high grade explosives by high performance liquid chromatography (HPLC) with monolithic stationary phases. Two gradient methods were developed, the first for quantitative analysis of eleven explosives: HMX; RDX; Tetryl; TNT; 2,3-DNT; 2,6-DNT; 3,4-DNT; 2-NT; 3-NT; 4-NT; and PETN in under 14 min. The second method separated seven explosives in under two min and is suitable for rapid screening to determine the presence of specific and/or class of explosive. The rapid screening methods were successfully applied to soils spiked with known amounts of target explosives. This technology showed excellent potential for forensic explosives detection and analysis.

Journal Article↗

PubMed2006

War and suicidal deaths by explosives in southwestern Croatia.

A total of 853 suicides, from which 29 were committed by explosives, were recorded in the examined region during three distinctly specific intervals-peace time (1986-1990), wartime (1991-1995), and the postwar time (1996-2000). Suicides caused by explosives, without a terrorist background, from 1986-2000 were reviewed. Out of 29 suicides by explosives committed in the examined period, the age and sex of suicide victims and alcohol intoxication at the time of suicide were analyzed. In the prewar period no suicides by explosives were recorded, in distinction from wartime and the postwar period when 20 and 9 such suicides were recorded, respectively. Alcohol testing was performed in 76% of the cases, showing the highest alcohol concentration in suicides' blood in wartime with an average value of 1.58 g/kg of absolute alcohol. As to the suicides' sex, 93% of the victims were male and 7% female. The paper emphasizes the drastically increased number of suicides committed by explosives in wartime.

Adult↗

PubMed2004

Chemotaxis-mediated biodegradation of cyclic nitramine explosives RDX, HMX, and CL-20 by Clostridium sp. EDB2.

Cyclic nitramine explosives, RDX, HMX, and CL-20 are hydrophobic pollutants with very little aqueous solubility. In sediment and soil environments, they are often attached to solid surfaces and/or trapped in pores and distribute heterogeneously in aqueous environments. For efficient bioremediation of these explosives, the microorganism(s) must access them by chemotaxis ability. In the present study, we isolated an obligate anaerobic bacterium Clostridium sp. strain EDB2 from a marine sediment. Strain EDB2, motile with numerous peritrichous flagella, demonstrated chemotactic response towards RDX, HMX, CL-20, and NO(2)(-). The three explosives were biotransformed by strain EDB2 via N-denitration with concomitant release of NO(2)(-). Biotransformation rates of RDX, HMX, and CL-20 by the resting cells of strain EDB2 were 1.8+/-0.2, 1.1+/-0.1, and 2.6+/-0.2nmol h(-1)mgwet biomass(-1) (mean+/-SD; n=3), respectively. We found that commonly seen RDX metabolites such as TNX, methylenedinitramine, and 4-nitro-2,4-diazabutanal neither produced NO(2)(-) during reaction with strain EDB2 nor they elicited chemotaxis response in strain EDB2. The above data suggested that NO(2)(-) released from explosives during their biotransformation might have elicited chemotaxis response in the bacterium. Biodegradation and chemotactic ability of strain EDB2 renders it useful in accelerating the bioremediation of explosives under in situ conditions.

Aza Compounds↗

PubMed2005

Determination and characterization of organic explosives using porous graphitic carbon and liquid chromatography-atmospheric pressure chemical ionization mass spectrometry.

A new LC-MS method for the determination and characterization of three groups of commonly used organic explosives (nitroaromatic compounds, cyclic nitroamines and nitrate esters) was developed using a porous graphitic carbon (PGC) (Hypercarb) column. Twenty-one different explosive-related compounds--including 2,4,6-trinitrotoluene, its by-products and its degradation products--were chromatographically separated in a single analysis. This efficient separation facilitates the identification of the manufacturer of the explosive using the identified analytes as a fingerprint. A final, conclusive identification of the analytes can be obtained using LC-MS equipped with an atmospheric pressure chemical ionization (APCI) interface. Solvent effects on chromatographic behaviour were investigated, as were the effects of solvent mixtures and mobile phase additives. The number and the relative positions of the nitro groups within analyte molecules influence their order of elution; these effects were investigated. The data thus generated can be interpreted to support a hypothesis concerning the retention mechanism of nitro-containing compounds when using PGC. Limits of detection ranged from 0.5 to 41.2 ng. The new methodology described herein improves the sensitivity and selectivity of explosive detection. The effectiveness of the method is demonstrated by the analysis of soil samples containing explosives residue from test fields in Sweden and Afghanistan.

Atmospheric Pressure↗

PubMed2004

Investigations of the formation of explosive mixtures in dryers for coatings.

In the following we will discuss a specific problem of explosion protection in dryers for coatings. It is mainly encountered in chamber dryers as these pose specific problems as regards occupational safety and health. During the drying process of most coatings, solvent vapours are released most of which can form explosive mixtures when a specific concentration, the lower explosion limit, is reached. The European Standard EN1539:2000 requires explosion venting areas for most of these dryers without adequate explosion protection measures such as appropriate limitation of the solvent input being taken into account. Different aspects of the model underlying the calculations are evaluated, and it will be shown that this model is still reliable in most applications. The investigations consisted of three parts. At first there have been made investigations of the operating conditions in different enterprises aimed to get information about specific parameters, problems and failures. Laboratory experiments have been made to investigate in detail the major influencing parameters. Attempts to set up a simple but basic physical model for the experimental data have also been made. Evaporation and diffusion have been examined. The numerical models have been kept as simple as possible to be a potential tool for designers/manufacturers and users.

Diffusion↗

PubMed2005

Dust explosion hazard of pulverized fuel carry-over.

This paper reports the results of experiments done to examine the explosibility of the waste products (fly ash and bottom ash) from pulverized fuels (coal and petroleum coke). Tests were conducted for the fly and bottom ashes alone and also for selected fly ashes blended with the fuels. The explosion parameters of interest were explosion pressure and rate of pressure rise. The fly ashes showed no propensity to explode, whereas one of the bottom ashes did show limited explosibility. Both findings can be explained with reference to the volatile matter content of the ashes. Admixture of either coal or petroleum coke with fly ash resulted in explosible mixtures at volatile contents in the range of 7-13%, with the value being dependent on the composition of the mixture components and their particle sizes.

Carbon↗