Journal articles: 'Explosives – Detection – Technique'

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Wang Gao, 王高, 周汉昌 Zhou Hanchang, 姚宝岱 Yao Baodai, 徐德刚 Xu Degang, and 姚建铨 Yao Jianquan. "Progress of Terahertz Spectroscopy Detection Technique of Explosives." Laser & Optoelectronics Progress 48, no. 1 (2011): 013001. http://dx.doi.org/10.3788/lop48.013001.

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MOWLAWI, ALI ASGHAR, and MAJED YAZDANI. "MONTE CARLO SIMULATION OF SOIL MOISTURE EFFECTS ON ANTI-TANK LANDMINES DETECTION BY NEUTRON BACKSCATTERING TECHNIQUE." International Journal of Modern Physics B 23, no. 32 (December 30, 2009): 5907–13. http://dx.doi.org/10.1142/s0217979209049735.

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The detection of landmines using available technologies is a time consuming, expensive, and extremely dangerous job, so that there is a need for technological breakthroughs in this field. One of the safest and most effective technologies to landmine and explosive detection is the neutron backscattering technique. The slowing-down of fast neutrons to the thermal energy is a direct measure of the concentration of hydrogen, one of the main elements present in explosive materials. The elastic scattering of fast neutrons is affected by the strong resonances in the cross-section of the three other elements of explosives: nitrogen, oxygen, and carbon. In this work, Monte Carlo estimations of the soil moisture effects on landmine detection are presented.

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Sharma, Ramesh, Subodh Kumar, Saurabh Gupta, and Hari Srivastava. "Ultrasonic Standoff Photoacoustic Sensor for the Detection of Explosive and Hazardous Molecules." Defence Science Journal 68, no. 4 (June 26, 2018): 401. http://dx.doi.org/10.14429/dsj.68.12454.

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<p>Standoff photoacoustic spectroscopic technique has been studied for the detection of hazardous molecules adsorbed on surfaces and in vapour/aerosols form in open air. Detection and identification of components in explosive mixtures in trace amounts is very challenging by any point or standoff spectroscopic detection technique. Discusses detection and identification of such components using standoff laser photoacoustic spectroscopic technique. Laser photoacoustic spectra of various trace molecules in the mid-infrared spectral band 7 μm - 9 μm have been recorded in vapor, aerosol, liquid forms as well as samples adsorbed on surfaces such as plastic and cloth. Pulsed quantum cascade laser is modulated at a frequency of 42 kHz resonant with that of microphone. Hazardous chemicals/explosives adsorbed on plastic and cloths surfaces were detected from a standoff distance up to 1.5 m. The sensitivities were found to be 20 μg/cm2, 20 μl liquid and 1.0 ppm corresponding to solid, liquid and vapour phases respectively. The chemicals/explosives used in the study were PETN, DNT, Acetone, and DMMP. Our study suggests that the photoacoustic technique has high selectivity and sensitivity for the trace detection and be used for screening of suspicious objects for security applications as a handy product.</p>

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Soma, Venugopal Rao, and Abdul Kalam Shaik. "Femtosecond Filaments for Standoff Detection of Explosives." Defence Science Journal 70, no. 4 (July 13, 2020): 359–65. http://dx.doi.org/10.14429/dsj.70.14962.

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In this report, we present our results from various studies to qualitatively discriminate the common military explosives viz. RDX, TNT and HMX in their pure form at a distance of ~6.5 m in standoff mode using femtosecond (fs) filament induced breakdown spectroscopy technique (fs FIBS) together with principal component analysis. A ~30 cm length fs filament obtained by a two-lens configuration was used to interrogate those energetic molecules in the form of pressed pellets (150 mg each). The plasma emissions were collected by a Schmidt-Cassegrain telescope (SCT) from a distance of ~8 m away from the investigation zone. Additionally, a few significant results obtained from the LIBS-based investigations of nitroimidazoles with respect to the standoff distance (~2 m) are discussed. Furthermore, we have also summarised a few important results from our recent investigations of bulk energetic materials in various configurations (including those with fs filaments). The results obtained from various fs FIBS configurations corroborate that the filament generation and its properties, the size and f-number of collection optics influence signal strength in the FIBS technique. These results project the fs FIBS technique as a potential technique for investigations aimed at hazardous materials and harsh environments in the standoff mode.

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Sawa, Zdzislaw P. "PFN GASCA technique for detection of explosives and drugs." Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms 79, no. 1-4 (June 1993): 593–96. http://dx.doi.org/10.1016/0168-583x(93)95421-z.

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Gokhale, P. P., and E. M. A. Hussein. "A 252Cf neutron transmission technique for bulk detection of explosives." Applied Radiation and Isotopes 48, no. 7 (July 1997): 973–79. http://dx.doi.org/10.1016/s0969-8043(97)00028-6.

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Vourvopoulos, G. "Pulsed fast/thermal neutron analysis: a technique for explosives detection." Talanta 54, no. 3 (May 10, 2001): 459–68. http://dx.doi.org/10.1016/s0039-9140(00)00544-0.

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Gürkan, Serkan, Mustafa Karapınar, and Seydi Doğan. "Detection and Imaging of Underground Objects for Distinguishing Explosives by Using a Fluxgate Sensor Array." Applied Sciences 9, no. 24 (December 11, 2019): 5415. http://dx.doi.org/10.3390/app9245415.

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Active and passive techniques are two different techniques with which to detect buried explosives. In practice, the most preferred active method works by broadcasting a signal underground. This signal may stimulate the buried explosive and cause it to explode. It is important to eliminate or minimize this drawback to ensure the safety of the detector operator. In this respect, it is important to increase the studies on the passive detection technique which is not currently used in practice. The aim of this study was to passively detect improvised explosive devices without stimulating them, and to classify underground objects as explosive or non-explosive. A fluxgate sensor array having 33 components was used for passive magnetic field measurements, and the nearest neighborhood algorithm was preferred for classifying the resulting data. In experimental studies, 33 different samples having different amounts of ferromagnetic properties were used. Successful imaging and classification were achieved for the measurements up to 20 cm below the surface of soil. Data were recorded as 32 × 25 matrices, and then they were reduced to 32 × 2 matrices having the same features. Samples having explosive properties were distinguished from other underground objects with success rates of 86% and 95% for 32 × 25 and 32 × 2 data matrices, respectively. Classification times for 32 × 25 and 32 × 2 data matrices were 42 ms and 3.62 ms, respectively. For data groups where the best results were obtained for the data matrices, frame numbers classified in one second were calculated as 23.80 and 276.2, respectively. False alarm rate achieved was 5.31%. The experimental results proved the successes of the matrices reduction and classification approach. One of the most common problems encountered in passive detecting techniques is that the sensor position affects the measurements negatively. In this paper, a solution has been proposed for this important problem.

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Jander, Peter, and Reinhard Noll. "Automated Detection of Fingerprint Traces of High Explosives Using Ultraviolet Raman Spectroscopy." Applied Spectroscopy 63, no. 5 (May 2009): 559–63. http://dx.doi.org/10.1366/000370209788346922.

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Ultraviolet (UV) resonance Raman spectroscopy is a promising technique for the detection of trace explosives. For real-world applications, it is necessary to develop data evaluation algorithms that automatically recognize the spectral features of explosives in a sample spectrum. We have developed a robust algorithm that can tolerate high levels of fluorescence background. We successfully demonstrated the detection of traces of ANFO and TNT explosives at surface coverage levels of 55 μg/cm2 in a blind test experiment. The sensitivity and selectivity is discussed in terms of receiver operating characteristics (ROC) curves.

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Ma, Li, Yu Quan Wen, and Nan Yan. "Synthesis and Characterization of New Mesoporous Silica Film Materials for Explosive Detection." Advanced Materials Research 652-654 (January 2013): 1912–15. http://dx.doi.org/10.4028/www.scientific.net/amr.652-654.1912.

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Trace explosives detection plays a more and more important role in military, civilian and opposition to state terrorism application. Through sol-gel technique and spin coating technology, three different types of surfactants as structure-directing agent， a series of different pore size mesoporous silica thin films with two-dimensional hexagonal structure doped by silylated naphthol fluorescence dye were successfully fabricated. By using fluorescence spectra method, different films doping fluorescence dye were sensed toward nitro explosive vapor such as 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), octahydro -1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), and exhibit rapid response rate and extremely high fluorescent quenching efficiency, close to 72% after 60s response to TNT. The results clearly show that mesoporous silica films, with different porous size and structure, easily to be prepared and own high sensitivity, could be used as a new alternative of trace explosive detecting material.

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Huang, Shi Duo, Leonidas Kolaitis, and David M. Lubman. "Detection of Explosives Using Laser Desorption in Ion Mobility Spectrometry/Mass Spectrometry." Applied Spectroscopy 41, no. 8 (November 1987): 1371–76. http://dx.doi.org/10.1366/0003702874447365.

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Laser desorption is used to volatilize explosive materials for analysis by ion mobility/mass spectrometry measurements. The laser desorption is performed at relatively low power (< 107 W/cm2) so that mainly neutrals are produced, which are subsequently ionized by 63Ni-β-source induced ion-molecule reactions at atmospheric pressure. Atmospheric pressure ionization, together with the soft vaporization method, produces relatively simple spectra of the explosives investigated, yielding ions that are very characteristic of each molecule for identification. The technique has great potential for high sensitivity based upon the combination of complete laser vaporization of the sample and the API method, which is an extremely efficient form of ionization for these molecules with high electron affinities.

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Bogue, Robert. "Remote chemical sensing: a review of techniques and recent developments." Sensor Review 38, no. 4 (September 17, 2018): 453–57. http://dx.doi.org/10.1108/sr-12-2017-0267.

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Purpose This paper aims to provide technical details of the techniques used for the remote detection of chemical compounds in a number of applications and also to highlight key research themes. Design/methodology/approach Following a short introduction, this first considers remote gas detection using the DIAL technique. Remote gas cloud imaging is then discussed, and this is followed by a review of chemical warfare agent detection technologies. A selection of research activities and product developments aimed at remotely detecting explosives are considered and, finally, brief concluding comments are drawn. Findings Remote gas sensing is now a practical reality, and products are available which can remotely detect, identify, quantify and in some cases visualise a wide range of toxic and environmentally threatening gases. These satisfy numerous industrial, environmental and military applications. Remotely detecting explosives poses a significant technological challenge, and despite some commercialisation, it remains the topic of an extensive research effort, much involving LIBS and Raman techniques. Importantly, much of this work also has potential in non-military applications, with several developments being shown to detect various industrially important compounds. Originality/value This provides a technical insight into the techniques and products used in a range of remote chemical sensing applications.

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Lehnert, A. L., M. Flaska, and K. J. Kearfott. "D-D neutron-scatter measurements for a novel explosives-detection technique." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 693 (November 2012): 195–202. http://dx.doi.org/10.1016/j.nima.2012.07.047.

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Roy, Tushar, Yogesh Kashyap, Mayank Shukla, Ashish Agrawal, Shefali Bajpai, Tarun Patel, and Amar Sinha. "Associated particle technique in single-sided geometry for detection of explosives." Applied Physics Letters 106, no. 12 (March 23, 2015): 124103. http://dx.doi.org/10.1063/1.4916337.

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Daniel, Nelson W., Ian R. Lewis, and Peter R. Griffiths. "Interpretation of Raman Spectra of Nitro-Containing Explosive Materials. Part II: The Implementation of Neural, Fuzzy, and Statistical Models for Unsupervised Pattern Recognition." Applied Spectroscopy 51, no. 12 (December 1997): 1868–79. http://dx.doi.org/10.1366/0003702971939695.

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The implementation of neural, fuzzy, and statistical models for the unsupervised pattern recognition and clustering of Fourier transform (FT)-Raman spectra of explosive materials is reported. In this work a statistical pattern recognition technique based on the concept of nearest-neighbors classification is described. Also the first application of both fuzzy clustering and a fuzzified Kohonen clustering network for the analysis of vibrational spectra is presented. Fuzzified Kohonen networks were found to perform as well as or better than the traditional fuzzy clustering technique. The unsupervised pattern recognition techniques, without the need for a priori structural information, yielded results which were comparable with those obtained by using a combination of a priori structural information and manual group-frequency analysis. This work demonstrates, via the use of a nitro-containing explosive data set, the utility of unsupervised pattern recognition techniques for the clustering, novelty detection, prototyping, and feature mapping of Raman spectra. The results of this work are directly applicable to the characterization of Raman spectra of explosives recorded with fiber-optic sampling.

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Sekhar, Praveen K., Jie Zhou, Hui Wang, and Eric R. Hamblin. "Trace Detection of Pentaerythritol Tetranitrate Using Electrochemical Gas Sensors." Journal of Sensors 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/234607.

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Selective and sensitive detection of trace amounts of pentaerythritol tetranitrate (PETN) is demonstrated. The screening system is based on a sampling/concentrator front end and electrochemical potentiometric gas sensor as the detector. A single sensor is operated in the dominant hydrocarbon (HC) and nitrogen oxides (NOx) mode by varying the sensor operating condition. The potentiometric sensor with integrated heaters was used to capture the signature of PETN. Quantitative measurements based on hydrocarbon and nitrogen oxide sensor responses indicated that the detector sensitivity scaled proportionally with the mass of the explosives (10 μg down to 200 ng). The ratio of the HC integrated peak area to the NOxintegrated peak area is identified as an indicator of selectivity. The HC/NOxratio is unique for PETN and has a range from 1.7 to 2.7. This detection technique has the potential to become an orthogonal technique to the existing explosive screening technologies for reducing the number of false positives/false negatives in a cost-effective manner.

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Johnson, J. Bruce, Susan D. Allen, Jonathan Merten, Lewis Johnson, Daniel Pinkham, and Scott W. Reeve. "Standoff Methods for the Detection of Threat Agents: A Review of Several Promising Laser-Based Techniques." Journal of Spectroscopy 2014 (2014): 1–13. http://dx.doi.org/10.1155/2014/613435.

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Detection of explosives, explosive precursors, or other threat agents presents a number of technological challenges for optical sensing methods. Certainly detecting trace levels of threat agents against a complex background is chief among these challenges; however, the related issues of multiple target distances (from standoff to proximity) and sampling time scales (from passive mines to rapid rate of march convoy protection) for different applications make it unlikely that a single technique will be ideal for all sensing situations. A number of methods for spanning the range of optical sensor technologies exist which, when integrated, could produce a fused sensor system possessing a high level of sensitivity to threat agents and a moderate standoff real-time capability appropriate for portal screening of personnel or vehicles. In this work, we focus on several promising, and potentially synergistic, laser-based methods for sensing threat agents. For each method, we have briefly outlined the technique and report on the current level of capability.

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Sabo, M., M. Malásková, and Š. Matejčík. "Laser desorption with corona discharge ion mobility spectrometry for direct surface detection of explosives." Analyst 139, no. 20 (2014): 5112–17. http://dx.doi.org/10.1039/c4an00621f.

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Paula, Greg. "Crime-Fighting Sensors." Mechanical Engineering 120, no. 01 (January 1, 1998): 66–68. http://dx.doi.org/10.1115/1.1998-jan-4.

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This article discusses crime fighting sensors that are being designed to identify ceramic weapons, plastic explosives, chemical weapons, and organic materials. They are also being developed to help protect citizens from terrorism and aid police in solving crimes. One organization leading the development of innovative antiterrorism sensing technologies is Sandia National Laboratories in Albuquerque, N.M. Among Sandia’s projects is an explosives-detection portal, designed for the Federal Aviation Administration (FAA). The portal is intended to help prevent airliner hijackings and bombings by identifying passengers, airport visitors, and employees who have been recently working with any of a wide variety of explosive chemicals. Upcoming tests with the Albuquerque Police Department’s crime lab are designed to help work out any bugs in the technique, define what kinds of evidence it can help find, and determine whether the system will be practical as a tool for law enforcement. Its most promising features are its portability and the fact that it does not contaminate evidence.

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Dorozhkin, L. M., V. A. Nefedov, A. G. Sabelnikov, and V. G. Sevastjanov. "Detection of trace amounts of explosives and/or explosive related compounds on various surfaces by a new sensing technique/material." Sensors and Actuators B: Chemical 99, no. 2-3 (May 2004): 568–70. http://dx.doi.org/10.1016/j.snb.2004.01.007.

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Glumac, Nick. "Absorption Spectroscopy Measurements in Optically Dense Explosive Fireballs Using a Modeless Broadband Dye Laser." Applied Spectroscopy 63, no. 9 (September 2009): 1075–80. http://dx.doi.org/10.1366/000370209789379268.

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A modeless broadband dye laser is applied to probe inside optically dense fireballs generated by high explosives using single-shot, high resolution absorption spectroscopy. Despite attenuation of the main beam by 98%, high signal-to-noise ratio absorption spectra of Al, Ti, and AlO are readily obtained at resolutions of 0.007 nm, and luminosity from the fireball is strongly rejected. Detection limits for atomic species are less than 200 ppb. The method offers good time resolution of chemistry within the fireball, and scaling laws suggest that this technique should be valid in explosives tests at least up to the gram scale.

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Yehya, F., A. K. Chaudhary, D. Srinivas, and K. Muralidharan. "Study of thermal decomposition mechanisms and low-level detection of explosives using pulsed photoacoustic technique." Applied Physics B 121, no. 2 (September 24, 2015): 193–202. http://dx.doi.org/10.1007/s00340-015-6218-6.

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Pérot, Bertrand, Cédric Carasco, Cyrille Eléon, Sébastien Bernard, Alix Sardet, Wassila El Kanawati, Clément Deyglun, et al. "Sea container inspection with tagged neutrons." EPJ Nuclear Sciences & Technologies 7 (2021): 6. http://dx.doi.org/10.1051/epjn/2021004.

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Neutron inspection of sea-going cargo containers has been widely studied in the past 20 yr to non-intrusively detect terrorist threats, like explosives or Special Nuclear Materials (SNM), and illicit goods, like narcotics or smuggling materials. Fast 14 MeV neutrons are produced by a portable generator with the t(d, n)α fusion reaction, and tagged in both direction and time thanks to the alpha particle detection. This Associated Particle Technique (APT) allows focusing inspection on specific areas of interest in the containers, previously identified as containing suspicious items with X-ray radiographic scanners or radiation portal monitors. We describe the principle of APT for non-nuclear material identification, and for nuclear material detection, then we provide illustrations of the performances for 10 min inspections with significant quantities (kilograms) of explosives, illicit drugs, or SNM, in different cargo cover loads (e.g. metallic, organic, or ceramic matrices).

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Prante, Marc, Christian Ude, Miriam Große, Lukas Raddatz, Ulrich Krings, Gernot John, Shimshon Belkin, and Thomas Scheper. "A Portable Biosensor for 2,4-Dinitrotoluene Vapors." Sensors 18, no. 12 (December 3, 2018): 4247. http://dx.doi.org/10.3390/s18124247.

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Buried explosive material, e.g., landmines, represent a severe issue for human safety all over the world. Most explosives consist of environmentally hazardous chemicals like 2,4,6-trinitrotoluene (TNT), carcinogenic 2,4-dinitrotoluene (2,4-DNT) and related compounds. Vapors leaking from buried landmines offer a detection marker for landmines, presenting an option to detect landmines without relying on metal detection. 2,4-Dinitrotoluene (DNT), an impurity and byproduct of common TNT synthesis, is a feasible detection marker since it is extremely volatile. We report on the construction of a wireless, handy and cost effective 2,4-dinitrotoluene biosensor combining recombinant bioluminescent bacterial cells and a compact, portable optical detection device. This biosensor could serve as a potential alternative to the current detection technique. The influence of temperature, oxygen and different immobilization procedures on bioluminescence were tested. Oxygen penetration depth in agarose gels was investigated, and showed that aeration with molecular oxygen is necessary to maintain bioluminescence activity at higher cell densities. Bioluminescence was low even at high cell densities and 2,4-DNT concentrations, hence optimization of different prototypes was carried out regarding radiation surface of the gels used for immobilization. These findings were applied to sensor construction, and 50 ppb gaseous 2,4-DNT was successfully detected.

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Ehlerding, Anneli, Ida Johansson, Sara Wallin, and Henric Östmark. "Resonance-Enhanced Raman Spectroscopy on Explosives Vapor at Standoff Distances." International Journal of Spectroscopy 2012 (February 22, 2012): 1–9. http://dx.doi.org/10.1155/2012/158715.

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Resonance-enhanced Raman spectroscopy has been used to perform standoff measurements on nitromethane (NM), 2,4-DNT, and 2,4,6-TNT in vapor phase. The Raman cross sections for NM, DNT, and TNT in vapor phase have been measured in the wavelength range 210–300 nm under laboratory conditions, in order to estimate how large resonance enhancement factors can be achieved for these explosives. The results show that the signal is enhanced up to 250,000 times for 2,4-DNT and up to 60,000 times for 2,4,6-TNT compared to the nonresonant signal at 532 nm. Realistic outdoor measurements on NM in vapor phase at 13 m distance were also performed, which indicate a potential for resonance Raman spectroscopy as a standoff technique for detection of vapor phase explosives. In addition, the Raman spectra of acetone, ethanol, and methanol were measured at the same wavelengths, and their influence on the spectrum from NM was investigated.

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Boumsellek, S., S. H. Alajajian, and A. Chutjian. "Negative-Ion formation in the explosives RDX, PETN, and TNT by using the reversal electron attachment detection technique." Journal of the American Society for Mass Spectrometry 3, no. 3 (March 1992): 243–47. http://dx.doi.org/10.1016/1044-0305(92)87008-m.

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Wojtas, J., J. Mikolajczyk, M. Nowakowski, B. Rutecka, R. Medrzycki, and Z. Bielecki. "Applying CEAS method to UV, VIS, and IR spectroscopy sensors." Bulletin of the Polish Academy of Sciences: Technical Sciences 59, no. 4 (December 1, 2011): 415–18. http://dx.doi.org/10.2478/v10175-011-0050-x.

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Applying CEAS method to UV, VIS, and IR spectroscopy sensorsIn the paper, several applications of Cavity Enhanced Absorption Spectroscopy (CEAS) for trace mater detection are described. NO2sensor was constructed using this technique with blue-violet lasers (395-440 nm). The sensor sensitivity reaches the level of single ppb and it was applied in security portal. For detection of two gases at the same time, two-channel sensor was constructed. Used method allows a significant reduction in the cost of optoelectronic CEAS sensor designed to measure of concentrations of many gases simultaneously. Successful monitoring of N2O and NO in the air requires high precision mid-infrared spectroscopy. The constructed sensors are able to measure concentration at ppb level. These sensors might be used for monitoring of atmospheric purity as well as for detection of explosives.

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Maziejuk, Mirosław, Wiesław Lisowski, Monika Szyposzyńska, Tomasz Sikora, and Anna Zalewska. "Differential Ion Mobility Spectrometry in Application to the Analysis of Gases and Vapours." Solid State Phenomena 223 (November 2014): 283–90. http://dx.doi.org/10.4028/www.scientific.net/ssp.223.283.

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Ion mobility spectrometry (IMS) is a technique used for the detection of chemical warfare agents (CWA), drugs, toxic industrial compounds (TIC), and explosives, when rapid detection should be performed (from a few to several seconds) for trace amounts of these substances. An important development of IMS technology is differential ion mobility spectrometry (DMS). DMS is also known as Field Asymmetric Waveform Ion Mobility Spectrometry (FAIMS). Detection possibilities of apparatus using the DMS method are based on the occurrence of the different mobilities of ions (K) in the alternating electric field. This dependence is characterized by the alpha function (α).This presentation shows methods and examples of the identification of chosen substances. The results for the dependence of coefficient α are specific for different types of substances. This specificity is used to identify vapours and gases.

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Huang, Xue Yi, Geng Guang Xu, and Feng Long Hao. "¹⁴N NQR Study of Urea and Thiourea." Advanced Materials Research 774-776 (September 2013): 757–62. http://dx.doi.org/10.4028/www.scientific.net/amr.774-776.757.

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Nuclear quadrupole resonance (NQR) is a newly developed branch of radio frequency (RF) spectroscopic technique, allowing the detection of many substances containing quadrupole nuclei, such as14N and35Cl, widely existing in explosives and narcotics respectively. In this paper, we focus on the research of its detection mechanism for14N in urea and thiourea. Based on the Density Functional Theory (DFT), employing Beckes three-parameter hybrid functional combined with Lee-Yang-Parr correlation functional (B3LYP), with 6-311++G(d,p) basis set, we have obtained the quantum chemical calculations by using Gaussian 09. Furthermore, experimental results and some discussions related are also presented. At last, we find that the absolute values of relative errors of NQR frequencies are all less than 2%, which indicates that this study is reasonable.

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Brensinger, Karen, Christopher Rollman, Christine Copper, Ashton Genzman, Jacqueline Rine, Ira Lurie, and Mehdi Moini. "Novel CE–MS technique for detection of high explosives using perfluorooctanoic acid as a MEKC and mass spectrometric complexation reagent." Forensic Science International 258 (January 2016): 74–79. http://dx.doi.org/10.1016/j.forsciint.2015.11.007.

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Bogue, Robert. "Detecting explosives and chemical weapons: a review of recent developments." Sensor Review 35, no. 3 (June 15, 2015): 237–43. http://dx.doi.org/10.1108/sr-12-2014-0754.

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Purpose – The purpose of this paper is to provide details of recent developments in sensors for detecting explosives and chemical warfare agents. Design/methodology/approach – Following an introduction, this paper first discusses a selection of new sensing techniques aimed at detecting explosives and explosive devices. It then considers new developments in sensors for detecting chemical warfare agents. Brief concluding comments are drawn. Findings – This paper shows that a diversity of sensor technologies is being investigated, including various advanced optical methods, nanomaterials, microelectromechanical system, electronic noses, biosensors and electrochemical techniques, several of which offer levels of sensitivity in the parts-per-trillion region. These not only have the potential to yield improved devices for detecting explosives and chemical weapons but may also play a role in health care, environmental monitoring, drug detection and industrial health and safety. Originality/value – In an era of escalating terrorism and military conflicts, this provides a timely review of new technologies for detecting explosives and chemical warfare agents.

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Lei, Xiaoqiong, Jun Zhang, Wenyuan Jin, Chen Han, and Xiwei Xu. "The application of ambient noise and reflection seismic exploration in an urban active fault survey." Interpretation 8, no. 4 (November 1, 2020): SU1—SU10. http://dx.doi.org/10.1190/int-2020-0085.1.

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As the detection of urban active faults becomes increasingly important, high-resolution detection of urban blind active faults is very important for urban planning, land use, and disaster risk reduction. However, it is difficult to determine the corresponding surface positions in the city environment for noise and building restrictions. The active source reflection seismic technique is considered the best technique to image faults with a high resolution and deep penetration. However, urban geophysical exploration must often consider the complex urban environment, which includes moving vehicles, dense power grids, and irregular buildings. These features make active source reflection seismic exploration difficult for wide application due to its drawbacks of high cost and the necessary use of explosives. In contrast, ambient noise seismic surveys have the advantages of continuous ambient noise sources, low cost, and fast deployment. These advantages are good for urban exploration. Although ambient noise seismic surveys have a lower resolution than active seismic surveys, their ultrahigh-density layout can improve the resolution. We have conducted two active source seismic lines and two ambient noise seismic lines near the Huangzhuang-Gaoliying fault (HGF) in a northern suburb of Beijing. The autocorrelation and crosscorrelation results are consistent with the active source reflection seismic results. They revealed the location of the HGF, which is composed of a set of steep dip faults. The study of the combination of the two techniques demonstrates that ambient noise seismic surveys are effective for urban active fault detection, especially for larger scale area surveys, and active source reflection seismic surveys can be used for detailed surveys. The combination of the two techniques has a higher efficiency and lower costs and can be widely used in blind urban active fault surveys.

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Kumari, Archana, A. K. Chaudhary, and K. Rajasekhar. "Study of charge transfer mechanism of PEDOT polymer for detection of solid TEX and CL-20 explosives using pulsed photoacoustic technique." Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 241 (November 2020): 118597. http://dx.doi.org/10.1016/j.saa.2020.118597.

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Moram, Sree Satya Bharati, Abdul Kalam Shaik, Chandu Byram, Syed Hamad, and Venugopal Rao Soma. "Instantaneous trace detection of nitro-explosives and mixtures with nanotextured silicon decorated with Ag–Au alloy nanoparticles using the SERS technique." Analytica Chimica Acta 1101 (March 2020): 157–68. http://dx.doi.org/10.1016/j.aca.2019.12.026.

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Zhang, Wei, Yue Tang, Anran Shi, Lirong Bao, Yun Shen, Ruiqi Shen, and Yinghua Ye. "Recent Developments in Spectroscopic Techniques for the Detection of Explosives." Materials 11, no. 8 (August 6, 2018): 1364. http://dx.doi.org/10.3390/ma11081364.

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Trace detection of explosives has been an ongoing challenge for decades and has become one of several critical problems in defense science; public safety; and global counter-terrorism. As a result, there is a growing interest in employing a wide variety of approaches to detect trace explosive residues. Spectroscopy-based techniques play an irreplaceable role for the detection of energetic substances due to the advantages of rapid, automatic, and non-contact. The present work provides a comprehensive review of the advances made over the past few years in the fields of the applications of terahertz (THz) spectroscopy; laser-induced breakdown spectroscopy (LIBS), Raman spectroscopy; and ion mobility spectrometry (IMS) for trace explosives detection. Furthermore, the advantages and limitations of various spectroscopy-based detection techniques are summarized. Finally, the future development for the detection of explosives is discussed.

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Dean, Scott N., Lisa C. Shriver-Lake, David A. Stenger, Jeffrey S. Erickson, Joel P. Golden, and Scott A. Trammell. "Machine Learning Techniques for Chemical Identification Using Cyclic Square Wave Voltammetry." Sensors 19, no. 10 (May 25, 2019): 2392. http://dx.doi.org/10.3390/s19102392.

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Electroanalytical techniques are useful for detection and identification because the instrumentation is simple and can support a wide variety of assays. One example is cyclic square wave voltammetry (CSWV), a practical detection technique for different classes of compounds including explosives, herbicides/pesticides, industrial compounds, and heavy metals. A key barrier to the widespread application of CSWV for chemical identification is the necessity of a high performance, generalizable classification algorithm. Here, machine and deep learning models were developed for classifying samples based on voltammograms alone. The highest performing models were Long Short-Term Memory (LSTM) and Fully Convolutional Networks (FCNs), depending on the dataset against which performance was assessed. When compared to other algorithms, previously used for classification of CSWV and other similar data, our LSTM and FCN-based neural networks achieve higher sensitivity and specificity with the area under the curve values from receiver operating characteristic (ROC) analyses greater than 0.99 for several datasets. Class activation maps were paired with CSWV scans to assist in understanding the decision-making process of the networks, and their ability to utilize this information was examined. The best-performing models were then successfully applied to new or holdout experimental data. An automated method for processing CSWV data, training machine learning models, and evaluating their prediction performance is described, and the tools generated provide support for the identification of compounds using CSWV from samples in the field.

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Szczurek, Andrzej, Monika Maciejewska, and Żaneta Zajiczek. "Univariate and multivariate DMS calibration for a single analyte." E3S Web of Conferences 100 (2019): 00078. http://dx.doi.org/10.1051/e3sconf/201910000078.

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Differential mobility spectrometry (DMS) is a promising measurement technique. It is used in the detection of chemical warfare agents, explosives, drugs, and volatile organic compounds. The measurement principle is based on separation of gas-phase ions according to their differential mobility in alternating low and high electric fields. The DMS measurement result is a two dimensional spectrum of ion current displayed as a function of separation voltage and compensation voltage. The DMS spectral peaks, in terms of their height, location and width, are affected by gas sample composition, separation field and the gas flow rate. In this work, there is presented the calibration procedure which utilises the univariate and multivariate approach to differential ion mobility spectrum. We demonstrated the possibility of a successful retrieval of quantitative information using partial least squares regression as well as univariate linear regression. However, the multivariate approach outperformed the univariate one in terms of the quality of the model and the concentration prediction accuracy.

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Lefferts, Merel J., and Martin R. Castell. "Vapour sensing of explosive materials." Analytical Methods 7, no. 21 (2015): 9005–17. http://dx.doi.org/10.1039/c5ay02262b.

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The ability to accurately and reliably detect the presence of explosives is critical in many civilian and military environments, and this is often achieved through the sensing of the vapour emitted by the explosive material. This review summarises established and recently developed detection techniques.

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Menzel, E. Roland, Kimberly K. Bouldin, and Russell H. Murdock. "Trace Explosives Detection by Photoluminescence." Scientific World JOURNAL 4 (2004): 55–66. http://dx.doi.org/10.1100/tsw.2004.7.

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Some field tests in counter-terrorism efforts to detect explosive traces employ chemistries that yield colored products. We have examined a test kit of this kind, ETKPlus, based on widely used chemistries and employed extensively by the Israel Police. Our investigation focuses on the prospect of gaining sensitivity by replacing the normal colorimetric modality with photoluminescence detection, which, to our knowledge, has not been explored to date. We find two or more orders of magnitude sensitivity gains for all explosives studied, using field-worthy photoluminescence techniques. We have also investigated a general lanthanide-based photoluminescence approach which shows promise and the ability to photoluminescence-detect trace explosives in the presence of intense background color and/or background fluorescence by time-resolved imaging.

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PUCKRIN, ELDON, JEAN-MARC THÉRIAULT, HUGO LAVOIE, DENIS DUBÉ, and PATRICK BROUSSEAU. "NOVEL APPLICATION OF PASSIVE STANDOFF RADIOMETRY FOR THE MEASUREMENT OF EXPLOSIVES." International Journal of High Speed Electronics and Systems 18, no. 02 (June 2008): 307–18. http://dx.doi.org/10.1142/s0129156408005369.

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The objective of this paper is to show that explosives may potentially be detected by passive standoff FTIR radiometry. It is demonstrated that many explosives exhibit a signature (fingerprint) in the longwave infrared (LWIR) region (i.e., 8 – 14 μm). Simulations using the radiative transfer model, MODTRAN4, clearly suggest that such materials can be identified when a thermal contrast exists between the material and its environment. The explosives considered in this study include octogen (HMX), trinitrotoluene (TNT), cyclonite (RDX), and the plastic explosives, C-4 and Detasheet-C. In addition, passive FTIR measurements of HMX have been performed in the field at standoff distances up to 60 m. The development of a passive standoff detection capability based on FTIR radiometry may be a potentially useful addition to the arsenal of measurement techniques that currently exist for the detection and identification of explosive threats.

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Bonczarowska, Marzena, Patryk Piątek, and Sławomir Brzeźnicki. "Hydrazine. Determination in workplace air with high performance liquid chromatography – spectrophotometric technique." Podstawy i Metody Oceny Środowiska Pracy 35, no. 1(99) (March 25, 2019): 45–57. http://dx.doi.org/10.5604/01.3001.0013.0804.

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Anhydrous hydrazine in room temperature is colorless fuming oily liquid with ammonia-like odor. It is used in various industries for electrolytic plating of metals on glass and plastics, as a chemical intermediate for the synthesis of pesticides, insecticides, medicines and days. It is used also as water treatment agent in energy industry (corrosion inhibitor), rocket propellant and as explosives material. Long term exposure to hydrazine may cause to skin irritation and allergic reactions. Diluted aqueous solutions of hydrazine may be irritating for skin, eye and respiratory tract. Epidemiologic studies shows that chronic exposure to hydrazine may cause cancer. In European Union hydrazine is classified as a carcinogenic substance (cat. 1B). Experts from International Agency for Research on Cancer (IARC) have classified hydrazine as a compound probably carcinogenic to humans (Group 2A). Due to decreasing of MAC value for hydrazine in Poland it was necessary to develop and validate a sensitive method for determining hydrazine concentrations in the workplace air in the range from 1/10 to 2 MAC values, in accordance with the requirements of Standard No. PN-EN 482. The study was performed using a liquid chromatograph with spectrophotometric detection. All chromatographic analysis were performed with Discovery LC-18 150 × 2,1 mm analytical column, which was eluted with mixture of acetonitrile and water (6:4 v/v). The method is based on the collection of hydrazine on glass fiber filter impregnated with sulfuric acid, extraction with mixture of sodium dihydrogen phosphate and EDTA, derivatization of extracted compound with benzaldehyde and chromatographic determination of resulted solution with HPLC technique. The method is linear (r = 0.9989) within the investigated working range 0.15–3.5 μg/ml (0.00125–0.029 mg/m3 for a 240-L air sample). Calculated limit of detection (LOD) and limit of quantification (LOQ) were 0.0007 μg/ml and 0.0023 μg/ml, respectively. The average extraction efficiency of hydrazine from filters was 97% and samples stored in refrigerator are stable for 14 days. The analytical method described in this paper enables determination of hydrazine in workplace air. The method is precise, accurate and it meets the criteria for procedures for measuring chemical agents listed in Standard No. PN-EN 482. The method can be used for assessing occupational exposure to hydrazine and associated risk to workers’ health. The developed method of determining hydrazine has been recorded as an analytical procedure (see appendix). This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

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Marchisio, Andrea, and Jean-Marc Tulliani. "Semiconducting Metal Oxides Nanocomposites for Enhanced Detection of Explosive Vapors." Ceramics 1, no. 1 (June 25, 2018): 98–119. http://dx.doi.org/10.3390/ceramics1010009.

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In recent years, the detection of ultratraces of nitroaromatic compounds (NACs), such as 2,4,6-trinitrotoluene (TNT), has gained considerable attention due to associated problems related to environment, security against terrorists and health. The principle of NACs detection is simple since any explosive emits a rather small, but detectable number of molecules. Thus, numerous detection techniques have been developed throughout the years, but their common limitations are rather large sizes and weights, high power consumption, unreliable detection with false alarms, insufficient sensitivity and/or chemical selectivity, and hyper-sensitivity to mechanical influences associated with very high price. Thus, there is a strong need of cheap, rapid, sensitive, and simple analytical methods for the detection and monitoring of these explosives in air. Semiconducting metal oxides (SMOs) allow the preparation of gas sensors able to partially or totally overcome these drawbacks, and this paper aims to shortly review the most recent SMOs nanocomposites able to sense explosives.

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P, Shoba. "Explosive Detection – An Integrated Technique." International Journal of Applied Science and Engineering Research 1, no. 5 (October 20, 2012): 669–77. http://dx.doi.org/10.6088/ijaser.0020101068.

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Leahy-Hoppa, Megan R., Michael J. Fitch, and Robert Osiander. "Terahertz spectroscopy techniques for explosives detection." Analytical and Bioanalytical Chemistry 395, no. 2 (May 5, 2009): 247–57. http://dx.doi.org/10.1007/s00216-009-2803-z.

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Sierra, Cesar, Leon Perez, Andrea Garzon, Juan Hinestroza, and Diana Sinuco. "Detection of antipersonnel landmines containing ANFO-based explosive: A review." Revista Colombiana de Química 49, no. 3 (November 6, 2020): 47–57. http://dx.doi.org/10.15446/rcq.v49n3.85301.

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After an internal conflict that lasted over half a century, the detection and removal of antipersonnel landmines in Colombia have become cumbersome challenges. Antipersonnel landmines remain scattered in Colombia and with a considerable impact on the central-western region. Most of these devices are handmade (therefore, they can also be classified as improvised explosive devices) and composed of ammonium nitrate and fossil fuel blend, a mixture known as ANFO. Due to several unique factors, including concealment tactics and non-conventional manufacturing techniques employed by guerrilla fighters, the most efficient method for the detection of ANFO-based antipersonnel landmines is the use of trained canines. This review aims at describing the current chemical strategies used in the detection of ANFO-based antipersonnel landmines. First, a detailed description of the different techniques used in the detection of explosives is made. Then, all the strategies reported in the world for antipersonnel landmines detection are described. Finally, the importance of the use of canines for antipersonnel landmines detection is explained.

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Lu Shuhua, 卢树华. "Detection of Explosives by Terahertz Spectroscopic Techniques." Laser & Optoelectronics Progress 49, no. 4 (2012): 040006. http://dx.doi.org/10.3788/lop49.040006.

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Caygill, J. Sarah, Frank Davis, and Seamus P. J. Higson. "Current trends in explosive detection techniques." Talanta 88 (January 2012): 14–29. http://dx.doi.org/10.1016/j.talanta.2011.11.043.

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Gozani, Tsahi, Richard E. Morgado, and Chris C. Seher. "Nuclear-based techniques for explosive detection." Journal of Energetic Materials 4, no. 1-4 (January 1986): 377–414. http://dx.doi.org/10.1080/07370658608011351.

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Bünning, Tobias Hartwig, Jennifer Susanne Strehse, Ann Christin Hollmann, Tom Bötticher, and Edmund Maser. "A Toolbox for the Determination of Nitroaromatic Explosives in Marine Water, Sediment, and Biota Samples on Femtogram Levels by GC-MS/MS." Toxics 9, no. 3 (March 16, 2021): 60. http://dx.doi.org/10.3390/toxics9030060.

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To determine the amount of the explosives 1,3-dinitrobenzene, 2,4-dinitrotoluene, 2,4,6-trinitrotoluene, and its metabolites in marine samples, a toolbox of methods was developed to enhance sample preparation and analysis of various types of marine samples, such as water, sediment, and different kinds of biota. To achieve this, established methods were adapted, improved, and combined. As a result, if explosive concentrations in sediment or mussel samples are greater than 10 ng per g, direct extraction allows for time-saving sample preparation; if concentrations are below 10 ng per g, techniques such as freeze-drying, ultrasonic, and solid-phase extraction can help to detect even picogram amounts. Two different GC-MS/MS methods were developed to enable the detection of these explosives in femtogram per microliter. With a splitless injector, limits of detection (LODs) between 77 and 333 fg/µL could be achieved in only 6.25 min. With the 5 µL programmable temperature vaporization—large volume method (PTV-LVI), LODs between 8 and 47 fg/µL could be achieved in less than 7 min. The detection limits achieved by these methods are among the lowest published to date. Their reliability has been tested and confirmed by measuring large and diverse sample sets.

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Kapoor, J. C., and G. K. Kannan. "Landmine Detection Technologies to Trace Explosive Vapour Detection Techniques." Defence Science Journal 57, no. 6 (November 21, 2007): 797–810. http://dx.doi.org/10.14429/dsj.57.1818.

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Journal articles on the topic 'Explosives – Detection – Technique'

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