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Trace explosives

Qiang Zhao, Jianli Liu, Bo Wang, Xiaohua Zhang, Guangyan Huang, Wei Xu
Rapid, direct and trace detection of explosives in an open environment is of particular need in homeland and/or transportation security. In this work, an aerodynamic assisted thermo desorption mass spectrometry method was developed for the direct quantitative analyses of explosives from a distance. Remote non-volatile explosive sensing was achieved for 2, 4, 6-trinitrotoluene (TNT), trinitrohexahydro-1, 3, 5-triazine (RDX), 8701 (main ingredient: RDX 98.5%) and C4 (a type of plastic explosive) with a distance of 0...
October 13, 2016: Journal of Mass Spectrometry: JMS
Céline M Vidal, Nicole Métrich, Jean-Christophe Komorowski, Indyo Pratomo, Agnès Michel, Nugraha Kartadinata, Vincent Robert, Franck Lavigne
Large explosive eruptions inject volcanic gases and fine ash to stratospheric altitudes, contributing to global cooling at the Earth's surface and occasionally to ozone depletion. The modelling of the climate response to these strong injections of volatiles commonly relies on ice-core records of volcanic sulphate aerosols. Here we use an independent geochemical approach which demonstrates that the great 1257 eruption of Samalas (Lombok, Indonesia) released enough sulphur and halogen gases into the stratosphere to produce the reported global cooling during the second half of the 13th century, as well as potential substantial ozone destruction...
October 10, 2016: Scientific Reports
Frederick Li, Joseph Tice, Brian D Musselman, Adam B Hall
Improvised explosive devices (IEDs) are often used by terrorists and criminals to create public panic and destruction, necessitating rapid investigative information. However, backlogs in many forensic laboratories resulting in part from time-consuming GC-MS and LC-MS techniques prevent prompt analytical information. Direct analysis in real time - mass spectrometry (DART-MS) is a promising analytical technique that can address this challenge in the forensic science community by permitting rapid trace analysis of energetic materials...
September 2016: Science & Justice: Journal of the Forensic Science Society
James Barber
About 3 billion years ago an enzyme emerged which would dramatically change the chemical composition of our planet and set in motion an unprecedented explosion in biological activity. This enzyme used solar energy to power the thermodynamically and chemically demanding reaction of water splitting. In so doing it provided biology with an unlimited supply of reducing equivalents needed to convert carbon dioxide into the organic molecules of life while at the same time produced oxygen to transform our planetary atmosphere from an anaerobic to an aerobic state...
January 2016: Quarterly Reviews of Biophysics
Raffy Dotan, Glenn Jenkins, Thomas D O'Brien, Steve Hansen, Bareket Falk
BACKGROUND: Compared with visual torque-onset-detection (TOD), threshold-based TOD produces onset bias, which increases with lower torques or rates of torque development (RTD). PURPOSE: To compare the effects of differential TOD-bias on common contractile parameters in two torque-disparate groups. METHODS: Fifteen boys and 12 men performed maximal, explosive, isometric knee-extensions. Torque and EMG were recorded for each contraction. Best contractions were selected by peak torque (MVC) and peak RTD...
September 1, 2016: Journal of Electromyography and Kinesiology
Benjamin J Place, Matt J Perkins, Ewan Sinclair, Adam L Barsamian, Paul R Blakemore, Jennifer A Field
After the April 2010 explosion on the Deepwater Horizon oil rig, and subsequent release of millions of barrels of oil, two Corexit oil dispersant formulations were used in unprecedented quantities both on the surface and sub-surface of the Gulf of Mexico. Although the dispersant formulations contain four classes of surfactants, current studies to date focus on the anionic surfactant, bis-(2-ethylhexyl) sulfosuccinate (DOSS). Factors affecting the integrity of environmental and laboratory samples for Corexit analysis have not been systematically investigated...
July 2016: Deep-sea Research. Part II, Topical Studies in Oceanography
Chia-Wei Tsai, Anthony Midey, Ching Wu, Richard A Yost
Ammonium nitrate (AN) and urea nitrate (UN) are commonly used materials in improvised explosive devices (IEDs). Detection by mass spectrometry (MS) and/or ion mobility spectrometry (IMS) is traditionally difficult. The major challenges of detecting these species arise from their ionic nature and their low mass (for MS detection) and size (for IMS detection). Although AN and UN both produce characteristic higher mass (and size) cluster ions when ionized by electrospray ionization (ESI), detection of AN/UN using cluster ions poses difficulty at trace levels because their formation is concentration-dependent...
October 4, 2016: Analytical Chemistry
Qi Hu, Jacob Song Kiat Lim, Huan Liu, Yu Fu
Photoacoustic/photothermal spectroscopy is an established technique for trace detection of chemicals and explosives. However, prior sample preparation is required and the analysis is conducted in a sealed space with a high-sensitivity microphone or a piezo sensor coupled with a lock-in amplifier, limiting the technique to applications in a laboratory environment. Due to the aforementioned requirements, traditionally this technique may not be suitable for defense and security applications where the detection of explosives or hazardous chemicals is required in an open environment at a safe standoff distance...
August 22, 2016: Optics Express
Przemek Mróz, Andrzej Udalski, Paweł Pietrukowicz, Michał K Szymański, Igor Soszyński, Łukasz Wyrzykowski, Radosław Poleski, Szymon Kozłowski, Jan Skowron, Krzysztof Ulaczyk, Dorota Skowron, Michał Pawlak
Cataclysmic variable stars-novae, dwarf novae, and nova-likes-are close binary systems consisting of a white dwarf star (the primary) that is accreting matter from a low-mass companion star (the secondary). From time to time such systems undergo large-amplitude brightenings. The most spectacular eruptions, with a ten-thousandfold increase in brightness, occur in classical novae and are caused by a thermonuclear runaway on the surface of the white dwarf. Such eruptions are thought to recur on timescales of ten thousand to a million years...
August 17, 2016: Nature
M Savabieasfahani, S Sadik Ali, R Bacho, O Savabi, M Alsabbak
In war zones, the explosion of bombs, bullets, and other ammunition releases multiple neurotoxicants into the environment. The Middle East is currently the site of heavy environmental disruption by massive bombardments. A very large number of US military bases, which release highly toxic environmental contaminants, have also been erected since 2003. Current knowledge supports the hypothesis that war-created pollution is a major cause of rising birth defects and cancers in Iraq. We created elemental bio-imaging of trace elements in deciduous teeth of children with birth defects from Iraq...
September 2016: Environmental Monitoring and Assessment
Yonghuan Wang, Xiaozhi Wang, Lingfen Li, Chilai Chen, Tianbai Xu, Tao Wang, Jikui Luo
RATIONALE: High-Field Asymmetric Waveform Ion Mobility Spectrometry (FAIMS) is an analytical technique based on the principle of non-linear electric field dependence of coefficient of mobility of ions for separation that was originally conceived in the Soviet Union in the early 1980s. Being well developed over the past decades, FAIMS has become an efficient method for the separation and characterization of gas-phase ions at ambient pressure, often in air, to detect trace amounts of chemical species including explosives, toxic chemicals, chemical warfare agents and other compounds...
August 30, 2016: Rapid Communications in Mass Spectrometry: RCM
K Zhumadilov, Alexander Ivannikov, Valeriy Stepanenko, Shin Toyoda, Valeriy Skvortsov, Masaharu Hoshi
The method of electron paramagnetic resonance (EPR) dosimetry using extracted teeth has been applied to human tooth enamel to obtain individual absorbed doses of residents of settlements in the vicinity of the central axis of radioactive fallout trace from the contaminating surface nuclear test on 7 August 1962. Most of the settlements (Kurchatov, Akzhar, Begen, Buras, Grachi, Mayskoe, Semenovka) are located from 70 to 120  km to the North-East from the epicenter of the explosion at the Semipalatinsk Nuclear Test Site (SNTS)...
July 29, 2016: Radiation Protection Dosimetry
Xianming Kong, Yuting Xi, Paul Le Duff, Xinyuan Chong, Erwen Li, Fanghui Ren, Gregory L Rorrer, Alan X Wang
We demonstrate a photonic crystal biosilica surface-enhanced Raman scattering (SERS) substrate based on a diatom frustule with in-situ synthesized silver nanoparticles (Ag NPs) to detect explosive molecules from nanoliter (nL) solution. By integrating high density Ag NPs inside the nanopores of diatom biosilica, which is not achievable by traditional self-assembly techniques, we obtained ultra-high SERS sensitivity due to dual enhancement mechanisms. First, the hybrid plasmonic-photonic crystal biosilica with three dimensional morphologies was obtained by electroless-deposited Ag seeds at nanometer sized diatom frustule surface, which provides high density hot spots as well as strongly coupled optical resonances with the photonic crystal structure of diatom frustules...
July 19, 2016: Biosensors & Bioelectronics
Leonid A Turkevich, Joseph Fernback, Ashok G Dastidar, Paul Osterberg
There is a concern that engineered carbon nanoparticles, when manufactured on an industrial scale, will pose an explosion hazard. Explosion testing has been performed on 20 codes of carbonaceous powders. These include several different codes of SWCNTs (single-walled carbon nanotubes), MWCNTs (multi-walled carbon nanotubes) and CNFs (carbon nanofibers), graphene, diamond, fullerene, as well as several different control carbon blacks and graphites. Explosion screening was performed in a 20 L explosion chamber (ASTM E1226 protocol), at a concentration of 500 g/m(3), using a 5 kJ ignition source...
May 2016: Combustion and Flame
Jessica L Staymates, Matthew E Staymates, Jeffrey Lawrence
Sample collection for Ion Mobility Spectrometry (IMS) analysis is typically completed by swiping a collection wipe over a suspect surface to collect trace residues. The work presented here addresses the need for a method to measure the collection efficiency performance of surface wipe materials as a function of the number of times a wipe is used to interrogate a surface. The primary purpose of this study is to investigate the effect of wipe reuse, i.e., the number of times a wipe is swiped across a surface, on the overall particle collection and IMS response...
2016: International Journal for Ion Mobility Spectrometry
Sultan Ben-Jaber, William J Peveler, Raul Quesada-Cabrera, Emiliano Cortés, Carlos Sotelo-Vazquez, Nadia Abdul-Karim, Stefan A Maier, Ivan P Parkin
Surface-enhanced Raman spectroscopy is one of the most sensitive spectroscopic techniques available, with single-molecule detection possible on a range of noble-metal substrates. It is widely used to detect molecules that have a strong Raman response at very low concentrations. Here we present photo-induced-enhanced Raman spectroscopy, where the combination of plasmonic nanoparticles with a photo-activated substrate gives rise to large signal enhancement (an order of magnitude) for a wide range of small molecules, even those with a typically low Raman cross-section...
2016: Nature Communications
André Räupke, Alex Palma-Cando, Eugen Shkura, Peter Teckhausen, Andreas Polywka, Patrick Görrn, Ullrich Scherf, Thomas Riedl
We propose microporous networks (MPNs) of a light emitting spiro-carbazole based polymer (PSpCz) as luminescent sensor for nitro-aromatic compounds. The MPNs used in this study can be easily synthesized on arbitrarily sized/shaped substrates by simple and low-cost electrochemical deposition. The resulting MPN afford an extremely high specific surface area of 1300 m(2)/g, more than three orders of magnitude higher than that of the thin films of the respective monomer. We demonstrate, that the luminescence of PSpCz is selectively quenched by nitro-aromatic analytes, e...
2016: Scientific Reports
Joel B Lonzaga
Time reversal is used for localizing sources of recorded infrasound signals propagating in a windy, stratified atmosphere. Due to the convective effect of the background flow, the back-azimuths of the recorded signals can be substantially different from the source back-azimuth, posing a significant difficulty in source localization. The back-propagated signals are characterized by negative group velocities from which the source back-azimuth and source-to-receiver (STR) distance can be estimated using the apparent back-azimuths and trace velocities of the signals...
June 2016: Journal of the Acoustical Society of America
Maxime C Bridoux, Adrián Schwarzenberg, Sébastien Schramm, Richard B Cole
Direct Analysis in Real Time (DART™) high-resolution Orbitrap™ mass spectrometry (HRMS) in combination with Raman microscopy was used for the detailed molecular level characterization of explosives including not only the charge but also the complex matrix of binders, plasticizers, polymers, and other possible organic additives. A total of 15 defused military weapons including grenades, mines, rockets, submunitions, and mortars were examined. Swabs and wipes were used to collect trace (residual) amounts of explosives and their organic constituents from the defused military weapons and micrometer-size explosive particles were transferred using a vacuum suction-impact collection device (vacuum impactor) from wipe and swap samples to an impaction plate made of carbon...
August 2016: Analytical and Bioanalytical Chemistry
Aree Choodum, Khanitta Malathong, Niamh NicDaeid, Wadcharawadee Limsakul, Worawit Wongniramaikul
A cost effective hydrogel test kit was successfully developed for the detection of pre- and post-blast trinitrotoluene (TNT). A polyvinyl alcohol (PVA) hydrogel matrix was used to entrap the potassium hydroxide (KOH) colourimetric reagent. The easily portable test kit was fabricated in situ in a small tube to which the sample could be added directly. The test kit was used in conjunction with digital image colourimetry (DIC) to demonstrate the rapid quantitative analysis of TNT in a test soil sample. The built-in digital camera of an iPhone was used to capture digital images of the colourimetric products from the test kit...
September 2016: Forensic Science International
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