scholarly journals Surface Persistence of Trace Level Deposits of Highly Energetic Materials

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3494 ◽  
Author(s):  
Leonardo C. Pacheco-Londoño ◽  
José L. Ruiz-Caballero ◽  
Michael L. Ramírez-Cedeño ◽  
Ricardo Infante-Castillo ◽  
Nataly J. Gálan-Freyle ◽  
...  
Keyword(s):  
Energetic Materials ◽  
Metastable Phase ◽  
Grazing Angle ◽  
Sublimation Enthalpy ◽  
Gravimetric Analysis ◽  
Ftir Microscopy ◽  
Linear Behavior ◽  
Highly Energetic Materials ◽  
Ss Substrates ◽  
Enthalpies Of Sublimation

In the fields of Security and Defense, explosive traces must be analyzed at the sites of the terrorist events. The persistence on surfaces of these traces depends on the sublimation processes and the interactions with the surfaces. This study presents evidence that the sublimation process of these traces on stainless steel (SS) surfaces is very different than in bulk quantities. The enthalpies of sublimation of traces of four highly energetic materials: triacetone triperoxide (TATP), 2,4-dinitrotoluene (DNT), 2,4,6-trinitrotoluene (TNT), and 1,3,5- trinitrohexahydro-s-triazine (RDX) deposited on SS substrates were determined by optical fiber coupled-grazing angle probe Fourier Transform Infrared (FTIR) Spectroscopy. These were compared with enthalpies of sublimation determined by thermal gravimetric analysis for bulk amounts and differences between them were found. The sublimation enthalpy of RDX was very different for traces than for bulk quantities, attributed to two main factors. First, the beta-RDX phase was present at trace levels, unlike the case of bulk amounts which consisted only of the alpha-RDX phase. Second, an interaction between the RDX and SS was found. This interaction energy was determined using grazing angle FTIR microscopy. In the case of DNT and TNT, bulk and traces enthalpies were statistically similar, but it is evidenced that at the level of traces a metastable phase was observed. Finally, for TATP the enthalpies were statistically identical, but a non-linear behavior and a change of heat capacity values different from zero was found for both trace and bulk phases.

scholarly journals Surface Persistence of Trace Level Deposits of Highly Energetic Materials

2019 ◽  
Author(s):  
Leonardo C. Pacheco-Londoño ◽  
Jose L. Ruiz-Caballero ◽  
Michael L. Ramirez-Cedeño ◽  
Ricardo Infante-Castillo ◽  
Nataly J. Galan-Freyle ◽  
...  
Keyword(s):  
Energetic Materials ◽  
Grazing Angle ◽  
Surface Concentration ◽  
Beta Phase ◽  
Alpha Phase ◽  
Triacetone Triperoxide ◽  
Ftir Microscopy ◽  
Different Temperatures ◽  
Highly Energetic Materials ◽  
Ss Substrates

The sublimation enthalpies of four highly energetic materials (HEMs): triacetone triperoxide (TATP), 2,4-dinitrotoluene (DNT), 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitrohexahydro-s-triazine (RDX) deposited on stainless steel (SS) substrates were determined by optical fibre coupled-grazing angle probe (GAP) FTIR spectroscopy and thermogravimetric analysis (TGA) for bulk crystaline HEMs samples. The desorption energy of RDX on SS was also studied using grazing angle FTIR microscopy. Metastable phases of 2,4-DNT and TNT were observed when deposited on SS, and their sublimation enthalpies values were obtained by GAP measurements and compared with those for the crystalline phases. The sublimation enthalpies for the alpha phase RDX was also determined by TGA measurements. A layer of crystalline beta phase RDX was observed on SS, and it's sublimation enthalpies was determinate by GAP. PLS calibration curves for the surface concentrations of RDX on SS were generated using GAP to determinate the surface concentration with time at different temperatures.

scholarly journals Active Mode Remote Infrared Spectroscopy Detection of TNT and PETN on Aluminum Substrates

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
John R. Castro-Suarez ◽  
Leonardo C. Pacheco-Londoño ◽  
Joaquín Aparicio-Bolaño ◽  
Samuel P. Hernández-Rivera
Keyword(s):  
Infrared Spectroscopy ◽  
Energetic Materials ◽  
Angle Of Incidence ◽  
Least Squares Regression ◽  
Active Mode ◽  
Infrared Telescope ◽  
Infrared Spectrometer ◽  
Highly Energetic Materials ◽  
Aluminum Plates ◽  
Aluminum Substrates

Two standoff detection systems were assembled using an infrared telescope coupled to a Fourier transform infrared spectrometer, a cryocooled mercury-cadmium telluride detector, and a telescope-coupled midinfrared excitation source. Samples of the highly energetic materials (HEMs) 2,4,6-trinitrotoluene (TNT) and pentaerythritol tetranitrate (PETN) were deposited on aluminum plates and detected at several source-target distances by carrying out remote infrared spectroscopy (RIRS) measurements on the aluminum substrates in active mode. The samples tested were placed at 1–30 m for the RIRS detection experiments. The effect of the angle of incidence/collection of the IR beams on the vibrational band intensities and the signal-to-noise ratios (S/N) were investigated. Experiments were performed at ambient temperature. Surface concentrations from 50 to 400 μg/cm2 were studied. Partial least squares regression analysis was applied to the spectra obtained. Overall, RIRS detection in active mode was useful for quantifying the HEMs deposited on the aluminum plates with a high confidence level up to the target-collector distances of 1–25 m.

Crystal Engineering for Creating Low Sensitivity and Highly Energetic Materials

2018 ◽  
Vol 18 (10) ◽  
pp. 5713-5726 ◽  
Author(s):  
Chaoyang Zhang ◽  
Fangbao Jiao ◽  
Hongzhen Li
Keyword(s):  
Crystal Engineering ◽  
Energetic Materials ◽  
Highly Energetic Materials ◽  
Low Sensitivity

Improved detection of highly energetic materials traces on surfaces by standoff laser-induced thermal emission incorporating neural networks

2013 ◽  
Author(s):  
Amanda Figueroa-Navedo ◽  
Nataly Y. Galán-Freyle ◽  
Leonardo C. Pacheco-Londoño ◽  
Samuel P. Hernández-Rivera
Keyword(s):  
Neural Networks ◽  
Energetic Materials ◽  
Thermal Emission ◽  
Highly Energetic Materials

scholarly journals Detection of Nitroaromatic and Peroxide Explosives in Air Using Infrared Spectroscopy: QCL and FTIR

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Leonardo C. Pacheco-Londoño ◽  
John R. Castro-Suarez ◽  
Samuel P. Hernández-Rivera
Keyword(s):  
Pattern Recognition ◽  
Infrared Spectroscopy ◽  
Gas Phase ◽  
Energetic Materials ◽  
Organic Peroxide ◽  
Triacetone Triperoxide ◽  
Quantum Cascade ◽  
Spectroscopic Information ◽  
Ft Ir ◽  
Highly Energetic Materials

A methodology for processing spectroscopic information using a chemometrics-based analysis was designed and implemented in the detection of highly energetic materials (HEMs) in the gas phase at trace levels. The presence of the nitroaromatic HEM 2,4-dinitrotoluene (2,4-DNT) and the cyclic organic peroxide triacetone triperoxide (TATP) in air was detected by chemometrics-enhanced vibrational spectroscopy. Several infrared experimental setups were tested using traditional heated sources (globar), modulated and nonmodulated FT-IR, and quantum cascade laser- (QCL-) based dispersive IR spectroscopy. The data obtained from the gas phase absorption experiments in the midinfrared (MIR) region were used for building the chemometrics models. Partial least-squares discriminant analysis (PLS-DA) was used to generate pattern recognition schemes for trace amounts of explosives in air. The QCL-based methodology exhibited a better capacity of discrimination for the detected presence of HEM in air compared to other methodologies.

Detection of Highly Energetic Materials on Non-Reflective Substrates Using Quantum Cascade Laser Spectroscopy

2015 ◽  
Vol 69 (9) ◽  
pp. 1023-1035 ◽  
Author(s):  
John R. Castro-Suarez ◽  
Migdalia Hidalgo-Santiago ◽  
Samuel P. Hernández-Rivera
Keyword(s):  
Laser Spectroscopy ◽  
Quantum Cascade Laser ◽  
Energetic Materials ◽  
Quantum Cascade ◽  
Highly Energetic Materials

Synthesis and comparison of copper(ii) complexes with various N-aminotetrazole ligands involving trinitrophenol anions

2019 ◽  
Vol 43 (46) ◽  
pp. 18193-18202 ◽  
Author(s):  
Maximilian H. H. Wurzenberger ◽  
Benjamin R. G. Bissinger ◽  
Marcus Lommel ◽  
Michael S. Gruhne ◽  
Norbert Szimhardt ◽  
...  
Keyword(s):  
Energetic Materials ◽  
Fine Tuning ◽  
Highly Energetic Materials

This study shows the fine-tuning adjustment of copper(ii) complexes by trinitrophenolates and different N-aminotetrazole ligands to applicable highly energetic materials.

FT-IR Standoff Detection of Thermally Excited Emissions of Trinitrotoluene (TNT) Deposited on Aluminum Substrates

2013 ◽  
Vol 67 (2) ◽  
pp. 181-186 ◽  
Author(s):  
John R. Castro-Suarez ◽  
Leonardo C. Pacheco-Londoño ◽  
Miguel Vélez-Reyes ◽  
Max Diem ◽  
Thomas J. Tague ◽  
...  
Keyword(s):  
Energetic Materials ◽  
Solid Phase ◽  
Detection System ◽  
Target Surface ◽  
Least Squares Regression ◽  
Passive Mode ◽  
Standoff Detection ◽  
Highly Energetic Materials ◽  
Aluminum Plates ◽  
Aluminum Substrates

A standoff detection system was assembled by coupling a reflecting telescope to a Fourier transform infrared spectrometer equipped with a cryo-cooled mercury cadmium telluride detector and used for detection of solid-phase samples deposited on substrates. Samples of highly energetic materials were deposited on aluminum substrates and detected at several collector-target distances by performing passive-mode, remote, infrared detection measurements on the heated analytes. Aluminum plates were used as support material, and 2,4,6-Trinitrotoluene (TNT) was used as the target. For standoff detection experiments, the samples were placed at different distances (4 to 55 m). Several target surface temperatures were investigated. Partial least squares regression analysis was applied to the analysis of the intensities of the spectra obtained. Overall, standoff detection in passive mode was useful for quantifying TNT deposited on the aluminum plates with high confidence up to target–collector distances of 55 m.

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