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PubMed2004

Electron and nuclear dynamics of molecular clusters in ultraintense laser fields. IV. Coulomb explosion of molecular heteroclusters.

In this paper we present a theoretical and computational study of the temporal dynamics and energetics of Coulomb explosion of (CD4)(n) and (CH4)(n) (n=55-4213) molecular heteroclusters in ultraintense (I=10(16)-10(19) W cm(-2)) laser fields, addressing the manifestation of electron dynamics, together with nuclear energetic and kinematic effects on the heterocluster Coulomb instability. The manifestations of the coupling between electron and nuclear dynamics were explored by molecular dynamics simulations for these heteroclusters coupled to Gaussian laser fields (pulse width tau=25 fs), elucidating outer ionization dynamics, nanoplasma screening effects (being significant for I< or =10(17) W cm(-2)), and the attainment of cluster vertical ionization (CVI) (at I=10(17) W cm(-2) for cluster radius R(0)< or =31 A). Nuclear kinematic effects on heterocluster Coulomb explosion are governed by the kinematic parameter eta=q(C)m(A)/q(A)m(C) for (CA(4))(n) clusters (A=H,D), where q(j) and m(j) (j=A,C) are the ionic charges and masses. Nonuniform heterocluster Coulomb explosion (eta >1) manifests an overrun effect of the light ions relative to the heavy ions, exhibiting the expansion of two spatially separated subclusters, with the light ions forming the outer subcluster at the outer edge of the spatial distribution. Important features of the energetics of heterocluster Coulomb explosion originate from energetic triggering effects of the driving of the light ions by the heavy ions (C(4+) for I=10(17)-10(18) W cm(-2) and C(6+) for I=10(19) W cm(-2)), as well as for kinematic effects. Based on the CVI assumption, scaling laws for the cluster size (radius R(0)) dependence of the energetics of uniform Coulomb explosion of heteroclusters (eta=1) were derived, with the size dependence of the average (E(j,av)) and maximal (E(j,M)) ion energies being E(j,av)=aR(0) (2) and E(j,M)=(5a/3)R(0) (2), as well as for the ion energy distributions P(E(j)) proportional to E(j) (1/2); E(j)< or =E(j,M). These results for uniform Coulomb explosion serve as benchmark reference data for the assessment of the effects of nonuniform explosion, where the CVI scaling law for the energetics still holds, with deviations of the a coefficient, which increase with increasing eta. Kinematic effects (for eta>1) result in an isotope effect, predicting the enhancement (by 9%-11%) of E(H,av) for Coulomb explosion of (C(4+)H(4) (+))(eta) (eta=3) relative to E(D,av) for Coulomb explosion of (C(4+)D(4) (+))(eta) (eta=1.5), with the isotope effect being determined by the ratio of the kinematic parameters for the pair of Coulomb exploding clusters. Kinematic effects for nonuniform explosion also result in a narrow isotope dependent energy distribution (of width DeltaE) of the light ions (with DeltaE/E(H,av) approximately 0.3 and DeltaE/E(D,av) approximately 0.4), with the distribution peaking at the high energy edge, in marked contrast with the uniform explosion case. Features of laser-heterocluster interactions were inferred from the analyses of the intensity dependent boundary radii (R(0))(I) and the corresponding average D+ ion energies (E(D,av))(I), which provide a measure for optimization of the cluster size at intensity I for the neutron yield from dd nuclear fusion driven by Coulomb explosion (NFDCE) of these heteroclusters. We infer on the advantage of deuterium containing heteronuclear clusters, e.g., (CD4)(n) in comparison to homonuclear clusters, e.g., (D2)(n/2), for dd NFDCE, where the highly charged heavy ions (e.g., C4+ or C6+) serve as energetic and kinematic triggers driving the D+ ions to a high (10-200 keV) energy domain.

Journal Article↗

PubMed2003

Biodegradation of nitro-explosives.

Environmental contamination by nitro compounds is associated principally with the explosives industry. However, global production and use of explosives is unavoidable. The presently widely used nitro-explosives are TNT (Trinitrotoluene), RDX (Royal Demolition Explosive) and HMX (High Melting Explosive). Nevertheless, the problems of these nitro-explosives are almost parallel due to their similarities of production processes, abundance of nitro-explosives and resembling chemical structures. The nitro-explosives per se as well as their environmental transformation products are toxic, showing symptoms as methaemoglobinaemia, kidney trouble, jaundice etc. Hence their removal/degradation from soil/water is essential. Aerobic and anaerobic degradation of TNT and RDX have been reported, while for HMX anaerobic or anoxic degradation have been described in many studies. A multisystem involvement using plants in remediation is gaining importance. Thus the information about degradation of nitro-explosives is available in jigsaw pieces which needs to be arranged and lacunae filled to get concrete degradative schemes so that environmental pollution from nitro-explosives can be dealt with more successfully at a macroscale. An overview of the reports on nitro-explosives degradation, future outlook and studies done by us are presented in this review.

Biodegradation, Environmental↗

PubMed2004

The role of context specificity in learning: the effects of training context on explosives detection in dogs.

Various experiments revealed that if an animal learns a stimulus-response-reinforcer relationship in one context and is then tested in another context there is usually a lessening of stimulus control, and the same discriminative stimuli that reliably controlled the behavior in the first context will have less effect in the new context. This reduction in performance is known as the "context shift effect." The effect of changing context on the probability of detecting explosives was investigated in seven highly trained explosives detection dogs (EDDs). In experiment 1 the dogs were trained alternately on path A, which always had five hidden explosives, and on a very similar path B, which never had any explosives. Within a few sessions the dogs showed a significant decrease in search behavior on path B, but not on path A. In experiment 2 the same dogs were trained only on path B with a target density of one explosive hidden every 4th day. The probability of the dogs now detecting the explosive was found to be significantly lower than in experiment 1. In experiment 3 the effect of the low target density as used in experiment 2 was investigated on a new but very similar path C. Both the detection probability for the one explosive every 4th day on the new path and the motivation to search were significantly higher than found in experiment 2. Finally, in experiment 4, an attempt was made to recondition the dogs to search on path B. Although trained for 12 daily sessions with one explosive hidden every session, the dogs failed to regain the normal levels of motivation they had shown on both new paths and on the paths that they knew usually contained explosives. The findings reveal that even a very intensively trained EDD will rapidly learn that a specific stretch of path does not contain explosives. The dog will then be less motivated to search and will miss newly placed targets. This learning is specific to the formerly always-clean path and is to some extent irreversible. However, the dog will search and detect normally on new paths even if they are very similar to the always-clean path. The data are discussed in terms of variables affecting renewal. The results suggest that following training designed to make a behavior "context independent," any extinction training will not generalize beyond that specific context used during the extinction training. In addition, if the behavior is extinguished in a specific context, it will be very difficult to restore that behavior in that context. These conclusions should be considered by anyone attempting to extinguish well-established trans-context behaviors.

Animals↗

PubMed2001

Use of visual evoked-potential studies and EEG data to classify aggressive, explosive behavior of youths.

OBJECTIVE: Data from electroencephalograms (EEGs), including data from visual evoked-potential studies, were analyzed to assess their association with a specific type of explosive behavior in children and adolescents. METHODS: Data for 326 children and adolescents treated in a psychiatric clinic were examined. Eighty-two percent exhibited behavior consistent with intermittent explosive disorder, although diagnosis was not an inclusion criterion for the study. The presence of explosive behaviors was indicated by reports from the legal system, schools, parents, health care workers, and psychiatric intake interviews. A quantitative EEG and a series of pattern-reversal evoked-potential studies were administered to each patient. In these studies, children are shown a rapidly reversing checkerboard pattern or rapid flashes of light, and their brain waves (evoked potentials) are measured. RESULTS: Logistic regression indicated that patients who exhibited explosive behaviors were significantly more likely to produce high-amplitude P100 wave forms in the evoked-potential studies than patients who did not exhibit explosive behaviors. Forty-six percent of those with explosive behaviors met the clinically defined electrophysiological criteria for the high-amplitude P100 wave forms. CONCLUSIONS: The use of visual evoked-potential studies helped us classify a large subset of youths who exhibited out-of-control explosive behaviors. The findings suggest that a subgroup of individuals exhibiting explosive behaviors may have a predisposition for violent or explosive behavior that is an innate characteristic of their central nervous system. An understanding of the etiology of explosive behaviors permits the use of more appropriate intervention and treatment strategies.

Adolescent↗

PubMed1999

A basic test method for the study of explosion treatment of waste chemicals from laboratories.

As a part of the research on the explosion treatment of waste chemicals from laboratories, a basic test method, which will provide the basis for our future research, was developed. First, the basic explosive, the scale of the explosion chamber and the assembly of the sample were decided. Then, measurement of detonation velocity was carried out, and the relationship between the quantity of explosive and the state of detonation propagation was obtained. A quantitative method for evaluating the decomposability of organic chemicals under explosion treatment was investigated. The results indicate that evaluating the explosion decomposability of organic chemicals from the gasification ratio could be used as a basic method provided that the excessive oxygen is approximately 62 mol% or higher. Finally, examinations of the possible effects of the quantity of explosive and conditions of atmosphere on the explosion decomposition of the model substance were conducted, and the basic test conditions regarding the quantity of explosive and condition of atmosphere were decided.

Explosions↗

PubMed2003

Pathologic features of suicidal deaths caused by explosives.

Suicidal explosions that lack a terrorist background are only rarely encountered in the field of forensic pathology. The investigation of explosion-related fatalities can be a substantial challenge in medicolegal casework. Determining whether the manner of death is suicide, homicide, or accident in such cases can present an especially difficult task to the forensic pathologist. This study considers the pathologic features of suicidal deaths caused by explosives without a terrorist background. The modus operandi of the decedents reflected familiarity and proficiency, or at least a degree of specialized knowledge, with the construction and use of explosive devices. All explosions were set off in confined spaces. The injury patterns consisted of a combination of primary blast injuries (e.g. decapitation, traumatic amputation of limbs, gross lacerations of the body surface, blast injuries of gas-containing and hollow organs), secondary blast injuries (e.g. splinter-induced penetrating trauma), tertiary blast injuries (e.g. abrasions and contusions), and burn injuries (mostly of the flash type). The previously described symmetric distribution pattern of injuries in suicidal explosions was apparent only to a certain degree in the present series. Our observation of superficially sharp-edged wound margins with bridging in the depths of the lesion in blast-induced lacerations of the skin should deserve further attention in forthcoming cases of explosion-related fatalities because this finding is a diagnostic possibility that may support the theory of an explosion-related fatality under special circumstances, e.g. when the body has been dumped away from the place of death. Because a terrorist attack may be initially suspected in each case of suicide involving explosives, the importance of a joint inquiry based on expertise from police investigators, bomb experts, and forensic pathologists is evident.

Adult↗

PubMed2001

Force developmental phase and reliability in explosive and voluntary grip exertions.

The purposes of this study were to clarify the reliability of two types of grip exertions, explosive grip exertion and voluntary grip exertion up to the maximal grip strength and to examine their force patterns using force-time parameters. Subjects were 100 healthy young male volunteers (age: 17.8+/-2.50 yr.) who had no upper limb injury. Grip strength was measured two times with voluntary grip and then two times with explosive grip. 11 parameters derived from the force-time curve were selected to measure the developmental phase of muscle contraction. The reliability of maximal grip strength in explosive and voluntary grip exertions was very high (intraclass correlation = .95, .93). The difference between two trials in explosive grip tended to be smaller than that for voluntary grip, and reliability of the exertion pattern was higher for explosive grip than voluntary grip. The times to reach 90% of the maximal grip strength and the maximal grip strength in explosive grip were shorter than those in voluntary grip. The other 8 force-time parameters had higher values in explosive grip than voluntary grip and higher reliabilities. The force-time parameters reflect the properties of explosive exertion. The results suggest the possibility that static explosive strength could be evaluated using these force-time parameters.

Adolescent↗

PubMed2003

Trends in explosive contamination.

This study sought to assign a rough order of magnitude for the amount of explosive residue likely to be available in real-world searches for clandestine explosives. A variety of explosives (TNT, TATP, HMX, AN, RDX, PETN) in various forms (powder, flake, detonating cord, plastic) were carefully weighed or cut into containers, and the amount of residue inadvertently remaining on the work area, hands, or containers was quantified. This was used to evaluate the spillage potential of each explosive. The adhesion of each explosive to a glass surface was quantified from amount of explosive adhering to the inside of a glass vial into which the explosive had been placed and then removed by vigorous tapping. In powdered form, most of the explosives--TNT, PETN, RDX, HMX, and TATP--exhibited similar spillage and adhesion to glass. However, PETN as sheet explosive and plasticized RDX (C-4), showed very little potential to contaminate surfaces, either by spillage or adhesion to glass.

Journal Article↗

PubMed2005

The analysis of high explosives by liquid chromatography/electrospray ionization mass spectrometry: multiplexed detection of negative ion adducts.

The negative ion electrospray ionization mass spectrometric (ESI-MS) detection of adducts of high explosives with chloride, formate, acetate, and nitrate was used to demonstrate the gas-phase interaction of neutral explosives with these anions. The relative intensities of the adduct species were determined to compare the competitive formation of the selected high explosives and anions. The relative stability of the adduct species varies, yielding preferential formation of certain anionic adducts with different high explosives. To exploit this effect, an isocratic high-performance liquid chromatography (HPLC)/ESI-MS method was developed and used for the simultaneous analysis of high explosives using two different techniques for the addition of the anionic additives; pre- and post-column. The results show that the pre-column approach provides similar results with improved selectivity for specific explosives. By detecting characteristic adduct species for each explosive, this method provides a qualitative and quantitative approach for the analysis and identification of high explosives.

Anions↗

PubMed2002

Explosibility boundaries for fly ash/pulverized fuel mixtures.

Incomplete combustion and subsequent fuel contamination of a waste stream can pose a serious explosion hazard. An example of this type of incident is the contamination of fly ash with unburned pulverized coal. The coal, if present in sufficient quantities in the mixture, can act as a fuel source for a potential explosion. Experiments were conducted in a 20l Siwek explosibility test chamber to determine the minimum fuel contamination of fly ash required to form an explosible mixture. A sample of fly ash from Ontario Power Generation (OPG) (Ont., Canada) was artificially contaminated with Pittsburgh pulverized coal dust (the surrogate used to represent unburned fuel dust). Additionally, the influence of fly ash particle size on the amount of fuel contaminant required to form an explosible mixture was examined. Fine and coarse size fractions of fly ash were obtained by screening the original sample of OPG fly ash. The results show that at least 21% Pittsburgh pulverized coal (or 10% volatile matter) was required to form an explosible mixture of the original fly ash sample and coal dust. The results also illustrate that fly ash particle size is important when examining the explosibility of the mixture. The fine size fraction of fly ash required a minimum of 25% coal dust (12% volatile matter) in the mixture for explosibility, whereas the coarse fly ash required only 10% coal dust (7% volatile matter). Thus, the larger the particle size of the inert fly ash component in the mixture, the greater the hazard.

Coal↗

PubMed2003

Explosive volcanism may not be an inevitable consequence of magma fragmentation.

The fragmentation of magma, containing abundant gas bubbles, is thought to be the defining characteristic of explosive eruptions. When viscous stresses associated with the growth of bubbles and the flow of the ascending magma exceed the strength of the melt, the magma breaks into disconnected fragments suspended within an expanding gas phase. Although repeated effusive and explosive eruptions for individual volcanoes are common, the dynamics governing the transition between explosive and effusive eruptions remain unclear. Magmas for both types of eruptions originate from sources with similar volatile content, yet effusive lavas erupt considerably more degassed than their explosive counterparts. One mechanism for degassing during magma ascent, consistent with observations, is the generation of intermittent permeable fracture networks generated by non-explosive fragmentation near the conduit walls. Here we show that such fragmentation can occur by viscous shear in both effusive and explosive eruptions. Moreover, we suggest that such fragmentation may be important for magma degassing and the inhibition of explosive behaviour. This implies that, contrary to conventional views, explosive volcanism is not an inevitable consequence of magma fragmentation.

Journal Article↗

PubMed2004

Electron and nuclear dynamics of molecular clusters in ultraintense laser fields. III. Coulomb explosion of deuterium clusters.

In this paper we present a theoretical and computational study of the energetics and temporal dynamics of Coulomb explosion of molecular clusters of deuterium (D2)n/2 (n = 480 - 7.6 x 10(4), cluster radius R0 = 13.1 - 70 A) in ultraintense laser fields (laser peak intensity I = 10(15) - 10(20)W cm(-2)). The energetics of Coulomb explosion was inferred from the dependence of the maximal energy EM and the average energy Eav of the product D+ ions on the laser intensity, the laser pulse shape, the cluster radius, and the laser frequency. Electron dynamics of outer cluster ionization and nuclear dynamics of Coulomb explosion were investigated by molecular dynamics simulations. Several distinct laser pulse shape envelopes, involving a rectangular field, a Gaussian field, and a truncated Gaussian field, were employed to determine the validity range of the cluster vertical ionization (CVI) approximation. The CVI predicts that Eav, EM proportional to R0(2) and that the energy distribution is P(E) proportional to E1/2. For a rectangular laser pulse the CVI conditions are satisfied when complete outer ionization is obtained, with the outer ionization time toi being shorter than both the pulse width and the cluster radius doubling time tau2. By increasing toi, due to the increase of R0 or the decrease of I, we have shown that the deviation of Eav from the corresponding CVI value (Eav(CVI)) is (Eav(CVI) - Eav)/Eav(CVI) approximately (toi/2.91tau2)2. The Gaussian pulses trigger outer ionization induced by adiabatic following of the laser field and of the cluster size, providing a pseudo-CVI behavior at sufficiently large laser fields. The energetics manifest the existence of a finite range of CVI size dependence, with the validity range for the applicability of the CVI being R0 < or = (R0)I, with (R0)I representing an intensity dependent boundary radius. Relating electron dynamics of outer ionization to nuclear dynamics for Coulomb explosion induced by a Gaussian pulse, the boundary radius (R0)I and the corresponding ion average energy (Eav)I were inferred from simulations and described in terms of an electrostatic model. Two independent estimates of (R0)I, which involve the cluster size where the CVI relation breaks down and the cluster size for the attainment of complete outer ionization, are in good agreement with each other, as well as with the electrostatic model for cluster barrier suppression. The relation (Eav)I proportional to (R0)I(2) provides the validity range of the pseudo-CVI domain for the cluster sizes and laser intensities, where the energetics of D+ ions produced by Coulomb explosion of (D)n clusters is optimized. The currently available experimental data [Madison et al., Phys. Plasmas 11, 1 (2004)] for the energetics of Coulomb explosion of (D)n clusters (Eav = 5 - 7 keV at I = 2 x 10(18) W cm(-2)), together with our simulation data, lead to the estimates of R0 = 51 - 60 A, which exceed the experimental estimate of R0 = 45 A. The predicted anisotropy of the D+ ion energies in the Coulomb explosion at I = 10(18) W cm(-2) is in accord with experiment. We also explored the laser frequency dependence of the energetics of Coulomb explosion in the range nu = 0.1 - 2.1 fs(-1) (lambda = 3000 - 140 nm), which can be rationalized in terms of the electrostatic model.

Journal Article↗

PubMed2000

Explosive outbursts in children with Tourette's disorder.

OBJECTIVE: Sudden, explosive outbursts of behavior occur in some children with Tourette's disorder (TD). The etiology of these symptoms is unknown. This study investigated the relationship between explosive outbursts, TD, and its comorbid disorders. METHOD: Tic type and severity and the presence of specific comorbid disorders were compared in 37 children with TD and explosive outbursts and 31 children with TD who did not have such symptoms. RESULTS: Children with TD and explosive outbursts were more likely to demonstrate significant comorbid conditions, particularly attention-deficit/hyperactivity disorder, obsessive-compulsive disorder, and oppositional defiant disorder. Tic type and severity did not appear related to the presence of explosive outbursts. A highly significant relationship was demonstrated between the number of comorbid psychiatric diagnoses and explosive outbursts. CONCLUSIONS: Explosive outbursts in children with TD resemble intermittent explosive disorder and may reflect dysregulation of diverse domains of brain function. The presence of such symptoms should alert the clinician to underlying comorbid conditions.

Adolescent↗

PubMed2003

Nonterrorist suicidal deaths involving explosives.

Suicidal deaths involving explosives unconnected to terrorism are rare. The investigation of deaths from explosive devices requires a multidisciplinary collaborative effort, as demonstrated in this study. Reported are 2 cases of nonterrorist suicidal explosive-related deaths with massive craniocerebral destruction. The first case involves a 20-year-old man who was discovered in the basement apartment of his father's home seconds after an explosion. At the scene investigators recovered illegal improvised power-technique explosive devices, specifically M-100s, together with the victim's handwritten suicide note. The victim exhibited extensive craniofacial injuries, which medicolegal officials attributed to the decedent's intentionally placing one of these devices in his mouth. The second case involves a 46-year-old man who was found by his wife at his home. In the victim's facial wound, investigators recovered portions of a detonator blasting cap attached to electrical lead wires extending to his right hand. A suicide note was discovered at the scene. The appropriate collection of physical evidence at the scene of the explosion and a detailed examination of the victim's history is as important as documentation of injury patterns and recovery of trace evidence at autopsy. A basic understanding of the variety of explosive devices is also necessary. This investigatory approach greatly enhances the medicolegal death investigator's ability to reconstruct the fatal event as a means of separating accidental and homicidal explosive-related deaths from this uncommon form of suicide.

Adult↗

PubMed2000

Audiometric configurations following exposure to explosions.

OBJECTIVE: To determine the configurations in pathologic audiograms obtained in patients shortly after exposure to an explosion. DESIGN, SETTING, AND PATIENTS: Audiograms were performed in 143 patients (286 ears; 76 males and 67 females, with a mean age of 34.6 years [range, 11-79 years]) sent to the Department of Otolaryngology and Head and Neck Surgery in a city hospital located in the center of Jerusalem, Israel, after being injured in 4 severe explosions occurring in Jerusalem during 1995-1997. Most of the audiograms were obtained within 4 hours after the explosion, and the remaining were obtained within 4 days of the explosion. RESULTS: Of 200 pathologic audiograms, 93 (46%) showed a downward slope configuration, 82 (41%) showed a dip configuration, and 25 (12%) were flat. There were 38 audiograms (19%) with 6-kHz dips. In 82% of the patients, the audiometric configurations were similar in both ears. Patients with a slope configuration on the audiogram were significantly older than those with a dip configuration (mean age, 40.8 vs 32.8 years; P<.01). CONCLUSIONS: There does not appear to be a single typical audiometric configuration in patients exposed to explosions. The slope and dip configurations are most frequently seen and are approximately equal in their incidence. This observation may lead to better understanding damage to the inner ear as a result of an explosion. This study is distinctive because of the large number of audiograms obtained and the fact that most of them were obtained immediately after the explosion.

Adolescent↗

PubMed2004

Bioremediation of soils contaminated with explosives.

The large-scale industrial production and processing of munitions such as 2,4,6-trinitrotoluene (TNT) over the past 100 years led to the disposal of wastes containing explosives and nitrated organic by-products into the environment. In the US, the Army alone has estimated that over 1.2 million tons of soil have been contaminated with explosives, and the impact of explosives contamination in other countries is of similar magnitude. In recent years, growing concern about the health and ecological threats posed by man-made chemicals have led to studies of the toxicology of explosives, which have identified toxic and mutagenic effects of the common military explosives and their transformation products (Bruns-Nagel et al., 1999a; Fuchs et al., 2001; Homma-Takeda et al., 2002; Honeycutt et al., 1996; Rosenblatt et al., 1991; Spanggord et al., 1982; Tan et al., 1992 and Won et al., 1976). Because the cleanup of areas contaminated by explosives is now mandated because of public health concerns, considerable effort has been invested in finding economical remediation technologies. Biological treatment processes are often considered, since these are usually the least expensive means of destroying organic pollution. This review examines the most important groups of chemicals that must be treated at sites contaminated by explosives processing, the chemical and biological transformations they undergo, and commercial processes developed to exploit these transformations for treatment of contaminated soil. We critically examine about 150 papers on the topic, including approximately 60 published within the past 5 years.

Biodegradation, Environmental↗

PubMed2001

Fluorescence quenching as an indirect detection method for nitrated explosives.

A novel approach based on fluorescence quenching is presented for the analysis of nitrated explosives. Seventeen common explosives and their degradation products are shown to be potent quenchers of pyrene, having Stern-Volmer constants that generally increase with the degree of nitration. Aromatic explosives such as 2,4,6-trinitrotoluene (2,4,6-TNT) are more effective quenchers than aliphatic or nitramine explosives. In addition, nitroaromatic explosives are found to have unique interactions with pyrene that lead to a wavelength dependence of their Stern-Volmer constants. This phenomenon allows for their differentiation from other nitrated explosives. The fluorescence quenching method is then applied to the determination of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazine(HMX), 2,4,6-TNT, nitromethane, and ammonium nitrate in various commercial explosive samples. The samples are separated by capillary liquid chromatography with post-column addition of the pyrene solution and detection by laser-induced fluorescence. The indirect fluorescence quenching method shows increased sensitivity and selectivity over traditional UV-visible absorbance as well as the ability to detect a wider range of organic and inorganic nitrated compounds.

Air Pollutants↗

PubMed1998

[Clinical characteristics of burn caused by coal mine explosion].

OBJECTIVE: To investigate the characteristics of the burn injury caused by coal mine explosion so as to enhance the cure rate. METHODS: Analyse the therapeutic result after planned standard treatment of clinical patients and review historical patients. RESULTS: 1. Coal mine explosion includes two types, i.e., gas explosion and coal dust explosion. 2. This kind of burn is a combined injury with pathologic changes of burns as the main feature. Mechanical injury is the chief cause of early death. Blast injury mainly damages the lungs. The occurrence of carboxyhemoglobinemia is not often. 3. The amount of fluid infusion in the first 24 h in exudation phase is 8% less of the traditional formula. Alkaline balanced salt solution is supplied as electrolyte solution, which can provide 45% of necessary HCO3- for correction of acidosis. 4. No thorough debridement is imposed in the treatment of burn wound. Baking with electric bulb with topical SD-Ag in semi-exposure state can be used. 5. Inhalation injury chiefly occurs in upper respiratory tract. The main bacterial species causing complicated lung infection are Pseudomonas aeruginosa and Staphylococcus aureus. 6. When MSOF occurs, the most frequently involved organ and system are the kidney and respiratory system. 7. The main bacteria causing systemic invasive infection are enteric bacilli and Pseudomonas aeruginosa. Enteric bacilli infection may be enterogenic. The latter infection is chiefly the result of cross infection in hospital. CONCLUSION: The burn caused by coal mine explosion is a combined injury characterized by pathologic changes of burn as the main issue. This kind of burn has two types, i.e., gas-explosion-burn and coal-dust-explosion-burn.

Adolescent↗