Explosive sensitivity of methylammonium perchlorates

The explosive sensitivity of methylammonium perchlorates has been investigated by differential thermal analysis, thermogravimetric analysis, mass spectrometry and explosion delay experiments. The decomposition temperature of these compounds increases in the order CH3NH3ClO4>(CH3)2NH2ClO4>(CH3)3NHClO4. The activation energy shows the reverse order, indicating thereby that the stability increases with increasing substitution. Mass spectrometric investigation, however, suggests an increasing reactivity with increasing substitution. A possible explanation for such behaviour is proposed. It appears that explosion delay is correlated with thermal decomposition and impact sensitivity.

The Pandolf load carriage equation is a poor predictor of metabolic rate while wearing explosive ordnance disposal protective clothing

This investigation aimed to quantify metabolic rate when wearing an explosive ordnance disposal (EOD) ensemble (~33kg) during standing and locomotion; and determine whether the Pandolf load carriage equation accurately predicts metabolic rate when wearing an EOD ensemble during standing and locomotion. Ten males completed 8 trials with metabolic rate measured through indirect calorimetry. Walking in EOD at 2.5, 4.0 and 5.5km·h−1 was significantly (p < 0.05) greater than matched trials without the EOD ensemble by 49% (127W), 65% (213W) and 78% (345W), respectively. Mean bias (95% limits of agreement) between predicted and measured metabolism during standing, 2.5, 4 and 5.5km·h−1 were 47W (19 to 75W); −111W (−172 to −49W); −122W (−189 to −54W) and −158W (−245 to −72W), respectively. The Pandolf equation significantly underestimated measured metabolic rate during locomotion. These findings have practical implications for EOD technicians during training and operation and should be considered when developing maximum workload duration models and work-rest schedules.

Structure and explosive sensitivity relation in ring-substituted arylammonium perchlorates

The thermal and explosive characteristics of ring-substituted arylammonium perchlorates have been studied by differential thermal analysis, explosion delay, and impact-sensitivity measurements. The decomposition and dissociation temperatures, as well as activiation energy for explosion, increase with increasing basicity of the corresponding arylamine. These parameters, when plotted against σ, the Hammett substituent constant, show a linear relationship in the case of meta- and para-substituted derivatives. The results indicate that a proton transfer from arylammonium ion to perchlorate ion is involved in the decompostion and also in the explosion process of these arylammonium perchlorates.

Fluoranthene based fluorescent chemosensors for detection of explosive nitroaromatics

A novel fluoranthene based fluorescent chemosensor for the detection of picric acid (PA) at the parts per billion (ppb) level was evaluated. Static fluorescence quenching was the dominant process by intercalative pi-pi interaction between fluoranthene (S-1) and nitroaromatics.

Femtogram Detection of Explosive Nitroaromatics: Fluoranthene-Based Fluorescent Chemosensors

Herein we report a novel fluoranthene-based fluorescent fluorophore 7,10-bis(4-bromophenyl)-8,9-bis4-(hexyloxy)phenyl]fluoranthene (S-3) and its remarkable properties in applications of explosive detection. The sensitivity towards the detection of nitroaromatics (NACs) was evaluated through fluorescence quenching in solution, vapor, and contact mode approaches. The contact mode approach using thin-layer silica chromatograp- hic plates exhibited a femtogram (1.15 fg cm(-2)) detection limit for trinitrotoluene (TNT) and picric acid (PA), whereas the solution-phase quenching showed PA detection at the 2-20 ppb level. Fluorescence lifetime measurements revealed that the quenching is static in nature and the quenching process is fully reversible. Binding energies between model binding sites of the S-3 and analyte compounds reveal that analyte molecules enter into the cavity created by substituted phenyl rings of fluoranthene and are stabilized by strong intermolecular interactions with alkyl chains. It is anticipated that the sensor S-3 could be a promising material for the construction of portable optical devices for the detection of onsite explosive nitroaromatics.

Fluorescent Tris-Imidazolium Sensors for Picric Acid Explosive

Two new anthracene-functionalized fluorescent tris-imidazolium salts have been synthesized, characterized, and proven to be selective sensors for picric acid, which is a common constituent of many powerful explosives. Theoretical studies revealed an unusual ground-state electron transfer from picrate anion to the sensor molecules.

Fluoranthene based derivatives for detection of trace explosive Nitroaromatics

A series of fluoranthene derivatives (F1-F5) varied with nature and type of substituents were synthesized via Diels-Alder reaction followed by in situ decarbonylation. The solid state structures have been established through single crystal X-ray diffraction (XRD). The presence of extended conjugation and having two alkyloxy chains on phenyl rings induces flexibility to orient opposite to each other and interacts with another fluoranthene unit with weak pi-pi interactions and show unique supramolecular arrangements. The envisaged photophysical and DFT studies demonstrated that HOMO-LUMO levels were effectively tuned by different substituents with an optical band gap from 3.44 to 3.88 eV provoked to examine as sensitive fluorescent chemosensors for the detection of nitroaromatic compounds (NACs). The sensitivity toward the detection of NACs was evaluated through fluorescence quenching in solution (aqueous and non-aqueous) and solid state (vapor and contact mode). Fluorescence studies demonstrated that electron transfer occurs from the electron rich fluoranthene fluorophores to the electron deficient NACs by the dominant static quenching mechanism and the quenching process is reversible. It was found that the detection sensitivity increases with extent of conjugation on fluoranthene unit. The contact mode approach using thin layer silica chromatographic plates exhibits a femtogram (1.15 fg/cm(2)) detection limit for trinitrotoluene (TNT) and picric acid (PA), while the solution state fluorescence quenching shows for PA detection at the 2-20 ppb level. The sensing performance of fluoranthene thin films to NACs in aqueous solution reveals that fluorophores are highly selective towards the detection of PA. The smart performances of thin film fluorophores with high photostability have great advantage than those of conjugated polymers with superior sensitive detection of PA in groundwater.

Effects of Graphitization on the Synthesis of Ultrafine Diamond by Explosive Detonation

金刚石的石墨化对于炸药爆轰过程中金刚石的产出率有重要的影响。对碳相图进行了讨论,提出采用金刚石2石墨的动力学平衡线来评价炸药爆轰过程中金刚石的石墨化。通过数值模拟,对炸药爆轰过程中金刚石的石墨化进行了分析和讨论。

Explosive consolidation of amorphous cobalt-based alloys

This paper addresses the explosive consolidation of amorphous cobalt-based alloys. Using the experimental setup introduced in the present paper, specimens with high compact density, excellent magnetic properties and great wearability have been made. In comparison with permalloy and ferrite, the present specimens exhibit superior magnetic properties. Therefore, the compact is deemed as being a promising material for magnetic recording heads.

Non-die explosive forming of spherical pressure-vessels

This paper presents a newly developed method of manufacturing spherical pressure vessels based on the technology of non-die explosive forming. Compared with the traditional method, this technology does not need any dies and pressing equipment, so that the cost of the production process can be greatly reduced, especially for vessels of less than 100 m3 capacity.

A study of the mechanism of consolidating metal-powder under explosive-implosive shock-waves

A study of the two-dimensional flow pattern of particles in consolidation process under explosive-implosive shock waves has been performed to further understand the mechanism of shock-wave consolidation of metal powder, in which bunched low-carbon steel wires were used instead of powder. Pressure in the compact ranges from 6 to 30 GPa. Some wires were electroplated with brass, some pickled. By this means, the flow pattern at particle surfaces was observed. The interparticle bonding and microstructure have been investigated systematically for the consolidated specimens by means of optical and electron microscopy, as well as by microhardness. The experimental results presented here are qualitatively consistent with Williamson's numerical simulation result when particle arrangement is close packed, but yield more extensive information. The effect of surface condition of particle on consolidation quality was also studied in order to explore ways of increasing the strength of the compacts. Based on these experiments, a physical model for metal powder shock consolidation has been established.

Explosive Hyperinflation, Inflation Tax Laffer Curve and Modelling the use of Money

This paper analyzes the existence of an inflation tax Laffer curve (ITLC) in the context of two standard optimizing monetary models: a cash-in-advance model and a money in the utility function model. Agents’ preferences are characterized in the two models by a constant relative risk aversion utility function. Explosive hyperinflation rules out the presence of an ITLC. In the context of a cash-in-advance economy, this paper shows that explosive hyperinflation is feasible and thus an ITLC is ruled out whenever the relative risk aversion parameter is greater than one. In the context of an optimizing model with money in the utility function, this paper firstly shows that an ITLC is ruled out. Moreover, it is shown that explosive hyperinflations are more likely when the transactions role of money is more important. However, hyperinflationary paths are not feasible in this context unless certain restrictions are imposed.

Failure process analysis of cement under explosive loading with a generalized driven nonlinear threshold model

The microstructural heterogeneity and stress fluctuation play important roles in the failure process of brittle materials. In this paper, a generalized driven nonlinear threshold model with stress fluctuation is presented to study the effects of microstructural heterogeneity on continuum damage evolution. As an illustration, the failure process of cement material under explosive loading is analyzed using the model. The result agrees well with the experimental one, which proves the efficiency of the model.

Good Morning, America! The explosive U.S. awakening to the need for adaptation

Since the early years of the 21st century, and in particular since 2007, the U.S. has been awakening rapidly to the fact that climate change is underway and that even if stringent efforts are undertaken to mitigate greenhouse gas emissions, adaptation to the unavoidable impacts from the existing commitment to climate change is still needed and needs to be begun now. This report provides an historical overview of the public, political, and scientific concern with adaptation in the United States. It begins by briefly distinguishing ongoing, historical adaptation to environmental circumstances from deliberate adaptation to human‐induced climate change. It then describes the shift from the early concerns with climate change and adaptation to the more recent awakening to the need for a comprehensive approach to managing the risks from climate change. Ranging from the treatment of the topic in the news media to the drafting of bills in Congress, to state and local government activities with considerable engagement of NGOs, scientists and consultants, it is apparent that adaptation has finally, and explosively, emerged on the political agenda as a legitimate and needed subject for debate. At the same time, the current policy rush is not underlain by widespread public engagement and mobilization nor does it rest on a solid research foundation. Funding for vulnerability and adaptation research, establishing adequate decision support institutions, as well as the building of the necessary capacity in science, the consulting world, and in government agencies, lags far behind the need. (PDF contains 42 pages)