Dr. Vasanthi Sivaprakasam Profile

KEYWORDS: Particles, Light scattering, Laser scattering, Cameras, Mie scattering, Beam diameter, Plane waves, Gaussian beams, CCD cameras, Light sources and illumination

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Proceedings Article | 24 April 2020 Presentation + Paper

Multi-spectral SWIR Lidar for imaging and spectral discrimination through partial obscurations

Vasanthi Sivaprakasam, Michael Yetzbacher, Heath Gemar, Abbie Watnik

Proceedings Volume 11392, 113920D (2020) https://doi.org/10.1117/12.2556180

KEYWORDS: LIDAR, Reflectivity, Short wave infrared radiation, Signal detection, Sensors, Target detection, Calibration, Imaging systems

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Proceedings Article | 29 May 2013 Paper

Wavelength resolved polarized elastic scatter measurements from micron-sized single particles

Vasanthi Sivaprakasam, Jozsef Czege, Jay Eversole

Proceedings Volume 8710, 871018 (2013) https://doi.org/10.1117/12.2016398

KEYWORDS: Particles, Light scattering, Atmospheric particles, Scattering, Scatter measurement, Aerosols, Wave plates, Polarizers, Light sources, Polarimetry

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Proceedings Article | 2 October 2008 Paper

Single aerosol particle selection and capture using laser scattering and fluorescence

Jay Eversole, Vasanthi Sivaprakasam, Timothy Pletcher, David Keller

Proceedings Volume 7116, 71160F (2008) https://doi.org/10.1117/12.799890

KEYWORDS: Particles, Atmospheric particles, Aerosols, Luminescence, Laser scattering, Pulsed laser operation, Ultraviolet radiation, Continuous wave operation, Mirrors, Scattering

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Proceedings Article | 7 November 2007 Paper

Recent advances in the development of a novel aerosol sorting and deposition system for bio-threat sensing applications

Timothy Pletcher, Joseph McGinn, David Keller, Alan Huston, Jay Eversole, Vasanthi Sivaprakasam

Proceedings Volume 6739, 673910 (2007) https://doi.org/10.1117/12.737821

KEYWORDS: Particles, Atmospheric particles, Algorithm development, Aerosols, Ultraviolet radiation, Signal processing, Near infrared, Solar concentrators, Luminescence, Crystals

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Sarnoff Corporation and the Naval Research Laboratory, through support of the U.S. Department of Homeland Security, are developing an automated, high throughput bio-aerosol physical enrichment system designed for use as part of a biological-threat protection system. The Biological Aerosol-Capture-Enrichment (BioACE) system is a bio-aerosol collection system that combines three unique technologies to create physically enriched aerosol samples that can be subsequently interrogated by any number of bio-threat detection systems for the presence of threat agents. An air-to-air concentrator uses an inertial separation technique to highly concentrate an aerosol sample presented to a dual wavelength ultra-violet laser induced fluorescence (UVLIF) optical trigger used to discriminate potential threat particles from non-threat particles conveyed in a collimated particle stream. This particle classification information is used to trigger an electrostatic deposition mechanism to deposit only those particles determined to be potential bio-threats onto a stainless steel substrate. Non-threat particles are discarded with the exiting airflow. The goal for the most recent development effort has been the integration and optimization of these technologies into a unit capable of producing highly enriched particulate samples from ambient air containing variable background aerosol loading and type. Several key technical and engineering challenges were overcome during the course of this development including a unique solution for compensating particle velocity dispersion within the airflow, development of a real-time signal acquisition and detection algorithm for determining material type on a particle by particle basis at rates greater than 2000 particles per second, and the introduction of a robust method for transferring deposited particulate into a 50ul wet sample suitable for most advanced bio-detection techniques. This paper will briefly describe the overall system architecture and then concentrate on the various component and system design tradeoffs required to optimize sample enrichment performance. A system performance model will be presented along with detailed analysis of the optical system components and electronic signal processing needed for achieving high concentration sample enrichment. Experimental methods and data obtained in the laboratory setting and from real world environments will be described and used to support the performance model of the system. Finally, a number of air sampling scenarios will be analyzed using the system performance model to determine the applicability of the BioACE system to the various concepts of operation perceived to be needed for achieving a high performance bio-threat detect-to-protect system.

Proceedings Article | 2 May 2007 Paper

Field test results and ambient aerosol measurements using dual wavelength fluorescence excitation and elastic scatter for bio-aerosols

V. Sivaprakasam, A. Huston, H. B. Lin, J. Eversole, P. Falkenstein, A. Schultz

Proceedings Volume 6554, 65540R (2007) https://doi.org/10.1117/12.719326

KEYWORDS: Atmospheric particles, Luminescence, Aerosols, Particles, Beam splitters, Scattering, Sensors, Ultraviolet radiation, Light scattering, Pulsed laser operation

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Proceedings Article | 13 October 2006 Paper

Experimental performance of a novel aerosol sorting and deposition system for bio-threat sensing applications

Timothy Pletcher, Joseph McGinn, David Keller, Alan Huston, Jay Eversole, Vasanthi Sivaprakasam

Proceedings Volume 6398, 63980A (2006) https://doi.org/10.1117/12.686677

KEYWORDS: Particles, Atmospheric particles, Aerosols, Laser systems engineering, Particle systems, Prototyping, Mirrors, Aerodynamics, Microscopes, Sensing systems

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Proceedings Article | 29 December 2004 Paper

Optical classification of bioaerosols using UV fluorescence and IR absorption spectroscopy

Alan Huston, Vasanthi Sivaprakasam, Cathy Scotto, Horn-Bond Lin, Jay Eversole, Abraham Schultz, Jeff Willey

Proceedings Volume 5617, (2004) https://doi.org/10.1117/12.578062

KEYWORDS: Luminescence, Atmospheric particles, Aerosols, Infrared spectroscopy, Ultraviolet radiation, Proteins, Principal component analysis, Bacteria, Particles, Absorption spectroscopy

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Proceedings Article | 16 December 2004 Paper

Multiple UV wavelength excitation and fluorescence of bioaerosols

Vasanthi Sivaprakasam, Alan Huston, Cathy Scotto, Jay Eversole

Proceedings Volume 5585, (2004) https://doi.org/10.1117/12.571296

KEYWORDS: Luminescence, Atmospheric particles, Aerosols, Ultraviolet radiation, Particles, Light scattering, Principal component analysis, Pulsed laser operation, Beam splitters, Proteins

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Showing 5 of 12 publications

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