Surface Persistence of Trace Level Deposits of Highly Energetic Materials

Abstract

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.

Self-Simulated Learning Artificial Intelligence for the Detection of High Explosives in Soil by Mid Infrared Laser Spectroscopy

“…Other signals that stand out include the band at 1234 cm -1 and the band at 1034 cm -1 for -N-C-N stretch; the signals at 1016 cm -1 for the combination -N-NO 2 stretch and in-plane C-H bending. [53][54][55] Fig. 2(b) shows the reflectance spectra of the seven soil samples, identified by Soil-1, Soil-2, Soil-3, Soil-4, Soil 5, Soil-6, and Soil-7.…”

“…[15] Several groups have demonstrated the capability of remote sensing of HE and others analytes using MIR laser spectroscopy with QCLs. [14,[16][17][18][19][20][21][22][23][24][25][26][27] The typical methods used to detect HE is destructive, require sampling, transferring samples to the lab, and performing a proper treatment of the sample for later detection. These methods include protocols based on gas chromatography-mass spectroscopy (GC-MS), gas chromatography-chemiluminescence (GC-CL), ion mobility spectrometry (IMS), [28] immunosensors, [29] electrophoresis, [30] fluorescence, [31] electrochemical methods, [30,32] high-pressure liquid chromatography (HPLC), [33,34] and HPLC-MS. [33] However, in situ detection of HE in the soil is not easy due to the presence of solid interfering materials such as organic and inorganic compounds, which vary for each type of soil [35][36][37] which makes this detection a challenge for the analyst.…”