Dr. Jairo Castillo-Chara Profile

Dr. Jairo Castillo-Chara

at Fayetteville State Univ

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Publications (5)

Proceedings Article | 25 September 2007 Paper

Ab initio calculation of Raman vibrational signatures of 2,4-dinitrotoluene, 2,6-dinitrotoluene and 2,4,6-trinitrotoluene

Miguel Castro, Nairmen Mina, Jairo Castillo-Chara, César Manrique-Bastidas, Samuel Hernández-Rivera

Proceedings Volume 6756, 67560G (2007) https://doi.org/10.1117/12.752612

KEYWORDS: Raman spectroscopy, Molecules, Raman scattering, Surface enhanced Raman spectroscopy, Scattering, Explosives, Chemical species, Spectroscopy, Statistical analysis, Light scattering

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Proceedings Article | 10 June 2005 Paper

Effect of environmental conditions on the spectroscopic signature of DNT in sand

Nairmen Mina, Samuel Hernandez-Rivera, Miguel Castro, Alejandro Blanco, Jairo Castillo-Chara

Proceedings Volume 5794, (2005) https://doi.org/10.1117/12.602452

KEYWORDS: Raman spectroscopy, Ultraviolet radiation, Explosives, Land mines, Spectroscopy, Crystals, Particles, Statistical analysis, Humidity, Environmental sensing

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Landmines have been a part of war technology for many years. As a result of the continued and indiscriminate use in approximately 90 countries landmines pose a severe and ever growing problem and a daily risk. Raman Spectroscopy is capable of providing rich information about the molecular structure of the sample and pinpoint detection of many chemicals, both of organic and inorganic nature. The presence of landmines in soils can be detected by Raman Spectroscopy sensing in a Point Detection modality, using characteristic vibrational signals of each explosive present in landmines. Detection of 2,4-DNT in sand and studies on how the vibrational signatures of 2,4-DNT is modified by interacting with soil particles and environmental conditions is reported. Raman Microspectrometers equipped with 514 nm and 785 nm laser excitation lines were used. The work focused in how the spectroscopic signatures of DNT in contact with Ottawa Sand are affected by the presence of humidity, pH, temperature, UV light and reaction times. Samples of mixtures of sand/2,4-DNT were analyzed by Raman Spectroscopy at 10, 50 and 100% water content and temperatures in range of 40-80 °C. Mixtures were also analyzed at different pH: 4, 7 and 10 and under ultraviolet light at 254 nm. Raman spectra were taken as a function of time in an interval from 24 to 336 hours (two weeks). Characteristic signals of 2,4-DNT were analyzed in different ranges 100-3800 cm^-1, 600-1200 cm^-1, 300-1700 cm^-1 and 2800-3500 cm^-1. The effect of these variables was measured during 45 consecutive days. It was confirmed that the decrease of characteristic vibrational signatures of 2,4-DNT can be attributed to increase of the degradation of 2,4-DNT by the simulated environmental conditions. Spectroscopic characterization of degradation products, both in contact with sand as well as airborne is under way. These results will make possible the development of highly sensitive sensors for detection of explosives materials and correlated with their degradation products in landmines.

Proceedings Article | 21 September 2004 Paper

Spectroscopic investigation of the spectroscopic signatures of 2,4-DNT and 2,6-DNT: their interactions with sand particles

Nairmen Mina, Samuel Hernandez-Rivera, Alejandro Blanco, Miguel Castro, Jairo Castillo-Chara

Proceedings Volume 5415, (2004) https://doi.org/10.1117/12.542870

KEYWORDS: Raman spectroscopy, Crystals, Spectroscopy, Explosives, Land mines, Particles, Crystallography, Microscopy, Sensors, Microscopes

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Proceedings Article | 21 September 2004 Paper

Nucleation and crystalization studies: a vibrational-spectroscopy investigation of 2,4,6-TNT

Nairmen Mina, Samuel Hernandez-Rivera, Cesar Manrique-Bastidas, Jairo Castillo-Chara, Miguel Castro

Proceedings Volume 5415, (2004) https://doi.org/10.1117/12.543302

KEYWORDS: Raman spectroscopy, Crystals, FT-IR spectroscopy, Spectroscopy, Explosives, Imaging spectroscopy, Photomicroscopy, Microscopy, Crystallography, Statistical analysis

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Proceedings Article | 21 September 2004 Paper

Spectroscopic characterization of nitroaromatic landmine signature explosives

Cesar Manrique-Bastidas, Samuel Hernandez-Rivera, Oliva Primera, Leonardo Pacheco, Nairmen Mina, Alejandro Blanco, Jairo Castillo-Chara, Miguel Castro

Proceedings Volume 5415, (2004) https://doi.org/10.1117/12.542895

KEYWORDS: Raman spectroscopy, Explosives, Land mines, Crystals, Spectroscopy, FT-IR spectroscopy, Infrared signatures, Sensors, Statistical analysis, Microscopy

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