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Security-Widefield, United States

Weatherall J.C.,Battelle | Barber J.,Battelle | Brauer C.S.,Oak Ridge Institute for Science and Education | Brauer C.S.,Pacific Northwest National Laboratory | And 8 more authors.
Applied Spectroscopy

Raman spectral data collected with high-resolution laboratory spectrometers are processed into a format suitable for importing as a user library on a 1064 nm DeltaNu first generation, field-deployable spectrometer prototype. The two laboratory systems used are a 1064 nm Bruker Fourier transform (FT)-Raman spectrometer and a 785 nm Kaiser dispersive spectrometer. The steps taken to adapt for device-dependent spectral resolution, wavenumber shifts between instruments, and relative intensity response are described. Effects due to the differing excitation laser wavelengths were found to be minimal, indicating - at least for the near-infrared (NIR) - that data can be ported between different systems, so long as certain measures are taken with regard to the reference and field spectra. © 2013 Society for Applied Spectroscopy. Source

Orton S.,University of Missouri | Chiarito V.,U.S. Army | Minor J.,U.S. Army | Coleman T.,Transportation Security Laboratory
International Journal of Protective Structures

This paper presents a simple procedure for the analysis of strengthened and unstrengthened reinforced concrete slabs under close-in blast loadings. The simplified procedure provides a tool to quickly check a slab or verify the results of a more advanced computer analysis. The procedure divides the response of the slab into breach, direct shear, flexural, and membrane behaviors and provides equations and references on how to calculate the capacity of each behavior. The procedure first checks the most severe failure modes, then progresses to other modes. The procedure was used to analyze the response of four slabs subjected to blasts; two of the slabs were strengthened with carbon-fiber reinforced polymer (CFRP) on the back face. The procedure was also used to analyze the response of a reinforced concrete box specimen strengthened with CFRP. The simple procedure accurately predicted the peak deflection of the slabs to close-in blast loadings. Source

Orton S.L.,University of Missouri | Chiarito V.P.,U.S. Army | Minor J.K.,U.S. Army | Coleman T.G.,Transportation Security Laboratory
Journal of Structural Engineering (United States)

Strengthening reinforced concrete slab or wall structural elements with carbon fiber-reinforced polymer (CFRP) can improve their blast resistance. However, close-in blasts (blasts with a scaled range of less than 0.4 m/kg1/3) may undermine the effectiveness of the CFRP strengthening. This paper presents an experimental testing program on CFRP-strengthened reinforced concrete slab specimens that utilized fiber anchors. Two CFRP mitigation designs were tested under blast loads with a scaled range of 0.4 and 0.6 m/kg1/3. Tests on unmitigated reinforced concrete slab specimens provided baseline comparisons. The experimental results showed that the use of CFRP strengthening improved the blast resistance of reinforced concrete slab specimens. For a larger scaled range, 0.6 m/kg1/3, the CFRP successfully prevented flying debris and reduced the overall deflections of the slab specimens. However, for the closer scaled range, 0.4 m/kg1/3, the high shock blast pressures shattered the concrete through the thickness of the slab specimen and tore through the back-face CFRP. However, back-face velocity and overall deflections were reduced by about 75% compared to the baseline test slab specimen. © 2013 American Society of Civil Engineers. Source

Windsor E.,U.S. National Institute of Standards and Technology | Najarro M.,U.S. National Institute of Standards and Technology | Bloom Jr. A.,U.S. National Institute of Standards and Technology | Benner B.,U.S. National Institute of Standards and Technology | And 3 more authors.
Analytical Chemistry

The feasibility of the use of piezoelectric drop-on-demand inkjet printing to prepare test materials for trace explosive analysis is demonstrated. RDX (1,3,5-trinitro-1,3,5 triazcyclohexane) was formulated into inkjet printable solutions and jetted onto substrates suitable for calibration of the ion mobility spectrometry (IMS) instruments currently deployed worldwide for contraband screening. Gravimetric analysis, gas chromatography/mass spectrometry (GC/MS), and ultraviolet-visible (UV-vis) absorption spectroscopy were used to verify inkjet printer solution concentrations and the quantity of explosive dispensed onto test materials. Reproducibility of the inkjet printing process for mass deposition of the explosive RDX (1,3,5-trinitro-1,3,5 triazcyclohexane) was determined to be better than 2% for a single day of printing and better than 3% day-to-day. © This article not subject to U.S. Copyright. Published 2010 by the American Chemical Society. Source

Basner M.,University of Pennsylvania | Rubinstein J.,Transportation Security Laboratory
Journal of Occupational and Environmental Medicine

Objective: To evaluate the ability of a 3-minute Psychomotor Vigilance Test (PVT) to predict fatigue-related performance decrements on a simulated luggage-screening task (SLST). Methods: Thirty-six healthy nonprofessional subjects (mean age = 30.8 years, 20 women) participated in a 4-day laboratory protocol including a 34-hour period of total sleep deprivation with PVT and SLST testing every 2 hours. Results: Eleven and 20 lapses (355-ms threshold) on the PVT optimally divided SLST performance into high-, medium-, and low-performance bouts with significantly decreasing threat detection performance A′. Assignment to the different SLST performance groups replicated homeostatic and circadian patterns during total sleep deprivation. Conclusions: The 3-minute PVT was able to predict performance on a simulated luggage-screening task. Fitness-for-duty feasibility should now be tested in professional screeners and operational environments. Copyright © 2011 by American College of Occupational and Environmental Medicine. Source

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