Chemistry and lung toxicity of particulate matter emitted from firearms.

Smoke emissions produced by firearms contain hazardous chemicals, but little is known if their properties change depending on firearm and ammunition type and whether such changes affect toxicity outcomes. Pulmonary toxicity was assessed in mice exposed by oropharyngeal aspiration to six different types of smoke-related particulate matter (PM) samples; (1) handgun PM, (2) rifle PM, (3) copper (Cu) particles (a surrogate for Cu in the rifle PM) with and without the Cu chelator penicillamine, (4) water-soluble components of the rifle PM, (5) soluble components with removal of metal ions, and (6) insoluble components of the rifle PM. Gun firing smoke PM was in the respirable size range but the chemical composition varied with high levels of Pb in the handgun and Cu in the rifle smoke.

Invited Article: Quantitative imaging of explosions with high-speed cameras.

The techniques presented in this paper allow for mapping of temperature, pressure, chemical species, and energy deposition during and following detonations of explosives, using high speed cameras as the main diagnostic tool. This work provides measurement in the explosive near to far-field (0-500 charge diameters) of surface temperatures, peak air-shock pressures, some chemical species signatures, shock energy deposition, and air shock formation.

High-speed two-camera imaging pyrometer for mapping fireball temperatures.

A high-speed imaging pyrometer was developed to investigate the behavior of flames and explosive events. The instrument consists of two monochrome high-speed Phantom v7.3 m cameras made by Vision Research Inc.

High-speed digital color imaging pyrometry.

Temperature measurements of high-explosive and combustion processes are difficult to obtain due to the speed and environment of the events. To overcome these challenges, we have characterized and calibrated a digital high-speed color camera that may be used to measure the temperature of such events. A two-color ratio method is used to calculate a temperature using the color filter array raw image data and a graybody assumption.

Acetylene measurement in flames by chirp-based quantum cascade laser spectrometry.

We have designed and characterized a mid-IR spectrometer built around a pulsed distributed-feedback quantum cascade laser using the characteristic frequency down-chirp to scan through the spectral region 6.5 cm(-1) spectral region. The behavior of this chirp is extensively measured.

Temporal evolution of the laser-induced breakdown spectroscopy spectrum of aluminum metal in different bath gases.

The spectral emission of gas-phase aluminum and aluminum oxide was measured during and immediately after exposure of a bulk-aluminum sample to a laser-induced spark produced by a focused, pulsed laser beam (Nd:YAG, 10-ns pulse duration, 35 mJ/pulse, lambda = 1064 nm). The spectral emission was measured as a function of time after the onset of the laser pulse, and it was also measured in different bath gases (air, nitrogen, oxygen, and helium).

Laser-induced breakdown spectroscopy of bacterial spores, molds, pollens, and protein: initial studies of discrimination potential.

Laser-induced breakdown spectroscopy (LIBS) has been used to study bacterial spores, molds, pollens, and proteins. Biosamples were prepared and deposited onto porous silver substrates. LIBS data from the individual laser shots were analyzed by principal-components analysis and were found to contain adequate information to afford discrimination among the different biomaterials.

Laser-induced breakdown spectroscopy analysis of energetic materials.

A number of energetic materials and explosives have been studied by laser-induced breakdown spectroscopy (LIBS). They include black powder, neat explosives such as TNT, PETN, HMX, and RDX (in various forms), propellants such as M43 and JA2, and military explosives such as C4 and LX-14. Each of these materials gives a unique spectrum, and generally the spectra are reproducible shot to shot.

Fourier-transform laser spectroscopy.

The development of microphotonic sensors based on Fourier-transform laser spectroscopy (FT-LS) is discussed. The application demonstrated is for measurement of vapors from the hydrocarbon fuels JP-8, diesel fuel, and gasoline. The two-laser prototype FT-LS sensor used for our research employs distributed-feedback lasers in the near-infrared spectral region (1.