That capability – never before reported in a remote bomb detection system – was described in a paper by Vanderbilt engineer Douglas Adams presented at the American Society of Mechanical Engineers Dynamic Systems and Control Conference on Oct. 23 in Stanford, CA.
A number of different tools are currently used for explosives detection. These range from dogs and honeybees to mass spectrometry, gas chromatography and specially designed X-ray machines.
“Existing methods require you to get quite close to the suspicious object,” said Adams, Distinguished Professor of Civil and Environmental Engineering. “The idea behind our project is to develop a system that will work from a distance to provide an additional degree of safety.”
Adams is developing the acoustic detection system with Christopher Watson and Jeffrey Rhoads at Purdue University and John Scales at the Colorado School of Mines as part of a major Office of Naval Research grant.
The new system consists of a phased acoustic array that focuses an intense sonic beam at a suspected improvised explosive device. At the same time, an instrument called a laser vibrometer is aimed at the object’s casing and records how the casing is vibrating in response. The nature of the vibrations can reveal a great deal about what is inside the container.
“We are applying techniques of laser vibrometry that have been developed for non-destructive inspection of materials and structures to the problem of bomb detection and they are working quite well,” Adams said.
In the current experiments, the engineers created two targets. One used an inert material that simulates the physical properties of low-yield explosive. The other was made from a simulant of high-yield explosive. They were fastened to acrylic caps to simulate plastic containers. Mechanical actuators substituted for the acoustic array to supply the sonic vibrations. The laser vibrometer was focused on the top of the plastic cap, corresponding to the outside of the bomb casing.
The tests clearly showed differences in the vibration patterns of the two caps that allow the researchers to distinguish between the two materials (hydroxyl-terminated polybutadiene polymer embedded with 50 percent and 75 percent by volume ammonium chloride crystals).
At the conference, Adams also showed a video of another test of the acoustic technique that showed it can differentiate between an empty container, one filled with water and one filled with a clay-like substance. The test used one-gallon plastic milk containers. In this case, the acoustic waves were produced by a device called an air driver. The empty jug had the largest vibrations while the jug containing the clay-like material had the smallest vibrations. The vibrations of the water-filled jug were in between.
The researchers have established that the best way to detect the contents of devices made of rigid material like metal is to use short ultrasonic waves. On the other hand, longer subsonic and infrasonic waves can be used to penetrate softer materials like plastics. Adam’s colleagues at Purdue are studying frequencies that can penetrate other materials like cloth.
The project is part of a $7 million multi-university research initiative led by North Carolina State University and funded by Office of Naval Research grant N00014-10-1-0958.
Visit Research News @ Vanderbilt for more research news from Vanderbilt. [Media Note: Vanderbilt has a 24/7 TV and radio studio with a dedicated fiber optic line and ISDN line. Use of the TV studio with Vanderbilt experts is free, except for reserving fiber time.]Contact:
David F. Salisbury | Vanderbilt University
Easier Diagnosis of Esophageal Cancer
06.03.2017 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Sandia uses confined nanoparticles to improve hydrogen storage materials performance
27.02.2017 | DOE/Sandia National Laboratories
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
30.03.2017 | Health and Medicine
30.03.2017 | Health and Medicine
30.03.2017 | Medical Engineering