A new 'semi-active' method for chemical standoff detection

2004 ◽  
Author(s):  
Tim J. Johnson ◽  
Bruce A. Roberts ◽  
Gerry P. Morgen ◽  
Michael A. Hughes ◽  
Corey D. Heitschmidt ◽  
...  
Keyword(s):  
Active Method ◽  
Standoff Detection

Short-range biological standoff detection system (SR-BSDS)

2000 ◽  
Author(s):  
V. James Cannaliato ◽  
Bruce W. Jezek ◽  
Larry Hyttinen ◽  
John B. Strawbridge ◽  
William J. Ginley
Keyword(s):  
Short Range ◽  
Detection System ◽  
Standoff Detection

RARE-EARTH DOPED POTASSIUM LEAD BROMIDE MID-IR LASER SOURCES FOR STANDOFF DETECTION

2008 ◽  
Vol 18 (03) ◽  
pp. 735-745 ◽  
Author(s):  
KRISHNA C. MANDAL ◽  
SUNG H. KANG ◽  
MICHAEL CHOI ◽  
R. DAVID RAUH
Keyword(s):  
Rare Earth ◽  
Emission Spectra ◽  
Optical Quality ◽  
Scanning Calorimetry ◽  
Laser Applications ◽  
Excellent Thermal Stability ◽  
Standoff Detection ◽  
Lead Bromide ◽  
Vertical Bridgman ◽  
Laser Crystals

The single crystal growth of KPb 2 Br 5 by vertical Bridgman technique using in-house processed zone refined PbBr 2 and KBr with rare-earth terbium doping has been studied. The grown moisture resistant crystals (1.5 cm diameter and 10 cm length) have shown high promise for low phonon energy room temperature solid-state laser applications in the longer side of mid-IR (4-15 µm) due to their high storage lifetimes, wide tunability, and excellent optical quality. The processed crystals are highly transparent ( T = ≥80%) in the 0.4-25 µm spectral region. Repeated melting-freezing cycles during differential scanning calorimetry (DSC) experiments did not reveal any appreciable variation in the melting point or phase transitions, which is indicative of their excellent thermal stability. The emission spectra pumped with a 2 µm source show broadband emissions with peak wavelength of 3 µ m (7 F 4→ 7 F6), 5µ m (7 F 5→ 7 F 6) and 7.9µ m (7 F 4→ 7 F 5). The KPb 2 Br 5: Tb laser crystals will be highly useful for standoff detection of incoming chemical and biological threats using unique infrared absorption signatures.

scholarly journals Over/Undervoltage and Undervoltage Shift of Hybrid Islanding Detection Method of Distributed Generation

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Manop Yingram ◽  
Suttichai Premrudeepreechacharn
Keyword(s):  
Control System ◽  
Distributed Generation ◽  
Hybrid Method ◽  
Detection Method ◽  
System Simulation ◽  
Detection Methods ◽  
Islanding Detection ◽  
Active Method ◽  
Passive Method ◽  
Simulation Results

The mainly used local islanding detection methods may be classified as active and passive methods. Passive methods do not perturb the system but they have larger nondetection zones, whereas active methods have smaller nondetection zones but they perturb the system. In this paper, a new hybrid method is proposed to solve this problem. An over/undervoltage (passive method) has been used to initiate an undervoltage shift (active method), which changes the undervoltage shift of inverter, when the passive method cannot have a clear discrimination between islanding and other events in the system. Simulation results on MATLAB/SIMULINK show that over/undervoltage and undervoltage shifts of hybrid islanding detection method are very effective because they can determine anti-islanding condition very fast.ΔP/P>38.41% could determine anti-islanding condition within 0.04 s;ΔP/P<-24.39% could determine anti-islanding condition within 0.04 s;-24.39%≤ΔP/P≤ 38.41% could determine anti-islanding condition within 0.08 s. This method perturbed the system, only in the case of-24.39% ≤ΔP/P ≤38.41% at which the control system of inverter injected a signal of undervoltage shift as necessary to check if the occurrence condition was an islanding condition or not.

Investigation of performance in suppressing various vibrations with energy-recycling semi-active method

2006 ◽  
Vol 58 (10) ◽  
pp. 506-514 ◽  
Author(s):  
Kanjuro Makihara ◽  
Junjiro Onoda ◽  
Masahiro Tsuchihashi
Keyword(s):  
Active Method

Dual-particle imager for standoff detection of special nuclear material

2011 ◽  
Author(s):  
J. Kyle Polack ◽  
Alexis Poitrasson-Riviere ◽  
Michael C. Hamel ◽  
Kiyotaka Ide ◽  
Kyle L. McMillan ◽  
...  
Keyword(s):  
Nuclear Material ◽  
Standoff Detection

Radon concentration in compressed natural gas and liquefied petroleum gas and its release range in residential houses

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Akbar Abbasi ◽  
Hesham M.H. Zakaly ◽  
Mahmoud M. Hessien
Keyword(s):  
Natural Gas ◽  
Radon Concentration ◽  
Concentration Distribution ◽  
Measurement Techniques ◽  
Concentration Measurement ◽  
Liquefied Petroleum Gas ◽  
Compressed Natural Gas ◽  
Radon Exposure ◽  
Active Method

Abstract Radon (222Rn) exposure in the environment is an important issue, and many pathways exist for radon exposure to humans. One of these pathways is 222Rn release through the consumption of natural gas. The issues of 222Rn concentration measurement techniques and worldwide concentration distribution were reviewed in natural gas, with emphasis on performing an active method to determine 222Rn concentration in LPG and CNG gases used in Cyprus. The obtained results were compared with 222Rn concentration in natural gas worldwide and UNSCEAR reports. The average 222Rn concentration value in LPG gas was observed higher than CNG gas. Also, the 222Rn concentration in LPG and CNG gases was less than the UNSCEAR reported value.

EXPRESS: Spectral Considerations for Standoff Infrared Detection of RDX on Reflective Aluminum

2021 ◽  
pp. 000370282110538
Author(s):  
Kevin J Major ◽  
Jas Sanghera ◽  
Mikella E. Farrell ◽  
Ellen L Holthoff ◽  
Paul M Pellegrino ◽  
...  
Keyword(s):  
Surface Concentration ◽  
Thin Layers ◽  
Infrared Detection ◽  
Aluminum Surface ◽  
Material System ◽  
Spectral Signatures ◽  
Spectral Changes ◽  
Standoff Detection ◽  
Infrared Spectrometer ◽  
Specific Material

This paper examines infrared spectroscopic effects for the standoff detection of an explosive material, hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), inkjet printed on an aluminum surface. Results of a spectroscopic study are described, using multiple optical setups. These setups were selected to explore how variations in the angles of incidence and collection from the surface of the material result in corresponding variations in the spectral signatures. The goal of these studies is to provide an understanding of these spectral changes, since it affects standoff detection of hazardous materials on a reflective substrate. We demonstrate that variations in spectral effects are dependent on the relative surface concentration of the deposited RDX. We also show that it is reasonable to use spectroscopic data collected in a standard laboratory infrared spectrometer outfitted with a variable angle reflectometer set at 0 as reference spectra for data collected in a standoff configuration. These results are important to provide a systematic approach to understanding IR spectra collection using standoff systems in the field, and to allow for comparison between such data, and data collected in the laboratory. Though the precise results are constrained to a specific material system (thin layers on a reflective substrate), the approach and general discussion provided are applicable to a broad range of IR standoff sensing techniques and applications.

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