The increase of terrorism and its global impact has made the screening of the contents of liquid-filled containers a
necessity. The ability to evaluate the contents of a container rapidly and accurately is a critical tool in maintaining global
safety and security. Due to the immense quantities and large variety of containers shipped worldwide, there is a need for
a technology that enables rapid and effective ways of conducting non-intrusive container inspections. Such inspections
can be performed utilizing "through-transmission" or "pulse-echo" acoustic techniques, in combination with multiple
frequency excitation pulses or waveforms. The challenge is combining and switching between the different acoustic
techniques without distorting the excitation pulse or waveform, degrading or adding noise to the receive signal; while
maintaining a portable, low-power, low-cost, and easy to use system.
The Pacific Northwest National Laboratory (PNNL) has developed a methodology and prototype device focused on this
challenge. The prototype relies on an advanced diplexer circuit capable of rapidly switching between both "through-transmission"
and "pulse-echo" detection modes. This type of detection requires the prototype to isolate the pulsing circuitry from the receiving circuitry to prevent damage and reduce noise.
The results of this work demonstrate that an advanced diplexer circuit can be effective; however, some bandwidth issues
exist. This paper focuses on laboratory measurements and test results acquired with the PNNL prototype device as
applied to several types of liquid-filled containers. Results of work conducted in the laboratory will be presented and
future measurement platform enhancements will be discussed.
KEYWORDS: Liquids, Acoustics, Signal attenuation, Ultrasonics, Temperature metrology, Transducers, Distance measurement, Signal to noise ratio, Inspection, Explosives
Work at the Pacific Northwest National Laboratory has demonstrated that ultrasonic property measurements
can be effectively employed for the rapid and accurate classification/discrimination of liquids in small, carry-on,
standard "stream-of-commerce" containers. This paper focuses on a set of laboratory measurements
acquired with the PNNL prototype device as applied to several types of liquids (including threat liquids and
precursor chemicals) to the manufacture of LEs in small commercially available plastic containers.
KEYWORDS: Transducers, Ultrasonics, Prototyping, Signal attenuation, Velocity measurements, Inspection, Signal to noise ratio, Signal processing, Distance measurement, Liquids
Government agencies and homeland security related organizations have identified the need to develop and establish a wide range of unprecedented capabilities for providing scientific and technical forensic services to investigations involving hazardous chemical, biological, and radiological materials, including extremely dangerous chemical and biological warfare agents. Pacific Northwest National Laboratory (PNNL) has developed a prototype portable, handheld, hazardous materials acoustic inspection prototype that provides noninvasive container interrogation and material identification capabilities using nondestructive ultrasonic velocity and attenuation measurements. Due to the wide variety of fluids as well as container sizes and materials encountered in various law enforcement inspection activities, the need for high measurement sensitivity and advanced ultrasonic measurement techniques were identified. The prototype was developed using a versatile electronics platform, advanced ultrasonic wave propagation methods, and advanced signal processing techniques. This paper primarily focuses on the ultrasonic measurement methods and signal processing techniques incorporated into the prototype. High bandwidth ultrasonic transducers combined with an advanced pulse compression technique allowed researchers to 1) obtain high signal-to-noise ratios and 2) obtain accurate and consistent time-of-flight (TOF) measurements through a variety of highly attenuative containers and fluid media. Results of work conducted in the laboratory have demonstrated that the prototype experimental measurement technique also provided information regarding container properties, which will be utilized in future container-independent measurements of hidden liquids.
KEYWORDS: Transducers, Ultrasonics, Prototyping, Signal attenuation, Velocity measurements, Signal to noise ratio, Inspection, Signal processing, Distance measurement, Liquids
Government agencies and homeland security related organizations have identified the need to develop and establish a wide range of unprecedented capabilities for providing scientific and technical forensic services to investigations involving hazardous chemical, biological, and radiological materials, including extremely dangerous chemical and biological warfare agents. Pacific Northwest National Laboratory (PNNL) has developed a prototype portable, hand-held, hazardous materials acoustic inspection prototype that provides noninvasive container interrogation and material identification capabilities using nondestructive ultrasonic velocity and attenuation measurements. Due to the wide variety of fluids as well as container sizes and materials encountered in various law enforcement inspection activities, the need for high measurement sensitivity and advanced ultrasonic measurement techniques were identified. The prototype was developed using a versatile electronics platform, advanced ultrasonic wave propagation methods, and advanced signal processing techniques. This paper primarily focuses on the ultrasonic measurement methods and signal processing techniques incorporated into the prototype. High bandwidth ultrasonic transducers combined with an advanced pulse compression technique allowed researchers to 1) obtain high signal-to-noise ratios and 2) obtain accurate and consistent time-of-flight (TOF) measurements through a variety of highly attenuative containers and fluid media. Results of work conducted in the laboratory have demonstrated that the prototype experimental measurement technique also provided information regarding container properties, which will be utilized in future container-independent measurements of hidden liquids.
Conference Committee Involvement (5)
Nondestructive Characterization for Composite Materials, Aerospace Engineering, Civil Infrastructure, and Homeland Security V
7 March 2011 | San Diego, California, United States
Nondestructive Characterization for Composite Materials, Aerospace Engineering, Civil Infrastructure, and Homeland Security IV
8 March 2010 | San Diego, California, United States
Nondestructive Characterization for Composite Materials, Aerospace Engineering, Civil Infrastructure, and Homeland Security III
9 March 2009 | San Diego, California, United States
Nondestructive Characterization for Composite Materials, Aerospace Engineering, Civil Infrastructure, and Homeland Security II
11 March 2008 | San Diego, California, United States
Nondestructive Characterization for Composite Materials, Aerospace Engineering, Civil Infrastructure, and Homeland Security
20 March 2007 | San Diego, California, United States
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