Narrow Results

The objective of the present study was to better understand the photophysics of explosives and chemical warfare simulants in order to develop better performing analytical tools. Photoionization mass spectra were taken using three optical schemes. The first was resonance-enhanced multiphoton ionization (REMPI) using few-ns duration 248 or 266 nm laser pulses. The second scheme was non-resonant multiphoton ionization (MPI) using 100 fs duration laser pulses at wavelengths between 325 and 795. The third approach was single photon ionization (SPI) using few-ns duration 118 nm laser pulses. For all the molecules investigated, mass spectra resulting exposure to ns-duration 248 or 266 nm laser pulses consisted of only low molecular weight fragments. Using fs-duration laser pulses produced more complicated, potentially analyzable, fragmentation patterns, usually with some parent peak. Single photon ionization gave the best results, with mass spectra consisting of almost only parent peak, except for the case of TATP.

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.

Density-function-theory calculations were performed to find the performance of a series of 2,2’-(1,2,4,5-tetrazine-3,6diyl) dihydrazinecarboxamide-based nitrogen-rich macrocyclic compounds as an energetic plasticizer. Reliable methods have been used to predict energetic properties such as gas-phase and solid-phase heat of formation (HOF), density, detonation velocity, detonation pressure, explosive power, heat of combustion, heat of detonation, specific impulse, flame temperature, brisance, and sensitivity. All the designed macrocycles possess a nitrogen content of over 48%. The designed compounds show positive HOFs and high predicted densities ranging from 1.81g/cm³ to 1.86g/cm³. The predicted properties were compared with GAP, polyGLYN and their monomers which establish the designed macrocycles of interest for further investigations concerning their suitability as plasticizers in energetic formulations.

The objective of the present study was to better understand the photophysics of explosives and chemical warfare simulants in order to develop better performing analytical tools. Photoionization mass spectra were taken using three optical schemes. The first was resonance-enhanced multiphoton ionization (REMPI) using few-ns duration 248 or 266 nm laser pulses. The second scheme was nonresonant multiphoton ionization (MPI) using 100 fs duration laser pulses at wavelengths between 325 and 795. The third approach was single photon ionization (SPI) using few-ns duration 118 nm laser pulses. For all the molecules investigated, mass spectra resulting exposure to ns-duration 248 or 266 nm laser pulses consisted of only low molecular weight fragments. Using fs-duration laser pulses produced more complicated, potentially analyzable, fragmentation patterns, usually with some parent peak. Single photon ionization gave the best results, with mass spectra consisting of almost only parent peak, except for the case of TATP.

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.

Effect of various amendments added to soils contaminated with explosives was studied under laboratory conditions. A mixture of bacterial isolates was inoculated into soils samples and incubated at +28 °C. After 14 days incubation, the pH and Eh level in the liquid fraction of soils amended with water was 6.73 and +34mV, in turn, with buffered solution was 7.2 and -30 mV, correspondingly. The total count of microorganisms in the samples was dependent on the presence of bacterial inoculum and nutrient amendments. Inoculation of soil samples with mixture of bacterial isolates had a strong effect on microbial community composition revealed by 16S rDNA-DGGE analysis. Several bacterial strains present in inoculum became dominant in TNT and RDX amended samples.

Water may become a medium for attacks through chemical, biological, radiological, nuclear, explosives, cyber impacts (CBRNE/cyber terrorism), and psychological operations from terrorists. The objective of this paper is to discuss strategies, policy, practice and technologies that prevent, disrupt, respond, mitigate and assist recovery from waterborne threats.

It is proposed that mitigation of potential waterborne components of CBRNE/cyber terrorism is critical for the sustainability of cities and that the problem can be addressed within a wider definition of waterborne threats to cover conflict, natural hazards and accidents as well as CBRNE/cyber terrorism. Included within the scope of this discussion are radiological ‘dirty bombs’, improvised nuclear devices and conventional conflicts between nations. Psychological operations of terror groups may have significant impacts in attacks on water facilities. Recommendations are made for new forms of fast, near-real time, trusted and unambiguous scientific communications techniques to mitigate unnecessary fear in the population and to limit other harmful effects.

Two case studies are presented to illustrate the importance of the sustainability of cities from waterborne threats. The first case study, of the Fukushima Daiichi Nuclear Power Plant (NPP) accident, shows the capacity of Tokyo to function despite city-wide contamination from Caesium-137 and Iodine-131—although rural Japan continues to have unresolved challenges to agricultural land sustainability a year after the disaster. The second case study discusses Iran as a country under threat of conflicts which may breach underground and aboveground nuclear facilities, including a nuclear reactor. The potential for a perceived threat to fragile water resources within this region illustrates the importance of scientific communications for real-time public advice (for example on whether any incident requires shelter in-situ or evacuation) and the formulation of twelve hour plans to recover cities’ water access to prevent panic and refugee movements.