Screening people for illicit substances: a survey of current portal technology

Hallowell, Susan F.

doi:10.1016/s0039-9140(00)00543-9

Cited by 145 publications

(73 citation statements)

References 4 publications

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“…The explosive fingerprint was described by Gresham et al [6], Carmack and Hembree [7] and later by Hallowell [8] as containing less than microgram levels of explosives. Carmack and Hembree [7] describe a standard solution of dissolved explosive as being composed mainly of binder materials that result in significant particle nucleation and growth upon drying of the standard solution on a surface.…”

Section: Introductionmentioning

confidence: 99%

Explosive Contamination from Substrate Surfaces: Differences and Similarities in Contamination Techniques Using RDX and C-4

Miller

Yoder

2010

Sens Imaging

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Explosive trace detection equipment has been deployed to airports for more than a decade. During this time, the need for standardized procedures and calibrated trace amounts for ensuring that the systems are operating properly and detecting the correct explosive has been apparent but a standard representative of a fingerprint has been elusive. Standards are also necessary to evaluate instrumentation in the laboratories during development and prior to deployment to determine sample throughput, probability of detection, false positive/negative rates, ease of use by operator, mechanical and/or software problems that may be encountered, and other pertinent parameters that would result in the equipment being unusable during field operations. Since many laboratories do not have access to nor are allowed to handle explosives, the equipment is tested using techniques aimed at simulating the actual explosives fingerprint. This laboratory study focused on examining the similarities and differences in three different surface contamination techniques that are used to performance test explosive trace detection equipment in an attempt to determine how effective the techniques are at replicating actual field samples and to offer scenarios where each contamination technique is applicable. The three techniques used were dry transfer deposition of standard solutions using the Transportation Security Laboratory's (TSL) patented dry transfer techniques (US patent 6470730), direct deposition of explosive standards onto substrates, and fingerprinting of actual explosives onto substrates. RDX was deposited on the surface of one of five substrates using one of the three different deposition techniques. The process was repeated for each substrate type using each contamination technique. The substrate types used were: 50% cotton/50% polyester as found in T-shirts, C. J. Miller (100% cotton with a smooth surface such as that found in a cotton dress shirt, 100% cotton on a rough surface such as that found on canvas or denim, suede leather such as might be found on jackets, purses, or shoes, and painted metal obtained from a car hood at a junk yard. The samples were not pre-cleaned prior to testing and contained sizing agents, and in the case of the metal, oil and dirt. The substrates were photographed using a Zeiss Discover V12 stereoscope with Axiocam ICc1 3 megapixel digital camera to determine the difference in the crystalline structure and surface contamination in an attempt to determine differences and similarities associated with current contamination deposition techniques. Some samples were analyzed using scanning electron microscopy (SEM) and some were extracted and analyzed with high performance liquid chromatography (HPLC) or gas chromatography with an electron capture detector (GC-ECD) to quantify the data.

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Section: Introductionmentioning

confidence: 99%

Explosive Contamination from Substrate Surfaces: Differences and Similarities in Contamination Techniques Using RDX and C-4

Miller

Yoder

2010

Sens Imaging

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“…However, real-time detection of explosives with high sensitivity and selectivity is a challenging task. [1][2][3] Use of explosives sniffing dogs, though attractive, is not very practical. 4,5 Presently used detection techniques are either bulky and expensive, such as ion mobility spectrometry devices, 6 or suffer from low sensitivity.…”

Section: Introductionmentioning

confidence: 99%

Micro-differential thermal analysis detection of adsorbed explosive molecules using microfabricated bridges

Senesac

Greve

et al. 2009

Review of Scientific Instruments

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Although micromechanical sensors enable chemical vapor sensing with unprecedented sensitivity using variations in mass and stress, obtaining chemical selectivity using the micromechanical response still remains as a crucial challenge. Chemoselectivity in vapor detection using immobilized selective layers that rely on weak chemical interactions provides only partial selectivity. Here we show that the very low thermal mass of micromechanical sensors can be used to produce unique responses that can be used for achieving chemical selectivity without losing sensitivity or reversibility. We demonstrate that this method is capable of differentiating explosive vapors from nonexplosives and is additionally capable of differentiating individual explosive vapors such as trinitrotoluene, pentaerythritol tetranitrate, and cyclotrimethylenetrinitromine. This method, based on a microfabricated bridge with a programmable heating rate, produces unique and reproducible thermal response patterns within 50 ms that are characteristic to classes of adsorbed explosive molecules. We demonstrate that this micro-differential thermal analysis technique can selectively detect explosives, providing a method for fast direct detection with a limit of detection of 600×10−12 g.

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“…1 Most of the existing EDP designs, however, tend to be highly intrusive and at times even startling to the unwary subject. For example, some of these designs use a series of brief puffer jets to loosen material from the subject.…”

Section: Introductionmentioning

confidence: 99%

Velocity Measurements of Doorway Flow Induced by an Air Curtain

Pierce

Yajin

Chauhan

et al. 2006

25th AIAA Aerodynamic Measurement Technology and Ground Testing Conference

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The airflow induced by an air curtain mounted over a doorway is examined for its potential use in explosive detection portals. A challenge to gaining understanding of such flows is mapping it using particle image velocimetry (PIV), a technique which is usually used in smaller-scale applications and with higher velocity flows. This paper discusses some of the challenges, requirements, techniques, and results of mapping large-scale flows with PIV, in particular, the mapping of a doorway flow induced by an air curtain.

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Screening people for illicit substances: a survey of current portal technology

Cited by 145 publications

References 4 publications

Explosive Contamination from Substrate Surfaces: Differences and Similarities in Contamination Techniques Using RDX and C-4

Explosive Contamination from Substrate Surfaces: Differences and Similarities in Contamination Techniques Using RDX and C-4

Micro-differential thermal analysis detection of adsorbed explosive molecules using microfabricated bridges

Velocity Measurements of Doorway Flow Induced by an Air Curtain

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