A new issue of this journal has just been published. To see abstracts of the papers it contains (with links through to the full papers) click here:
Selected papers from the latest issue:
Micromanipulation Using Cavitational Microstreaming Generated by Acoustically Oscillating Twin Bubbles
06 December 2011, 22:06:29
Publication year: 2011
Source: Sensors and Actuators A: Physical, Available online 6 December 2011
Kyung Ho Lee, Jeong Hyun Lee, Jung Min Won, Kyehan Rhee, Sang Kug Chung
This paper describes a novel non-invasive micromanipulation technique that employs the cavitational microstreaming generated by acoustically oscillating twin bubbles. First, a single acoustically oscillating bubble was attached to the tip of a rod that was combined with a three-dimensional traverse system, and a fish egg (diameter: 1 mm) was then manipulated in an aqueous medium. Although the microstreaming generated by the single oscillating bubble was sufficiently strong to push and move the fish egg, the manipulation direction was uncontrollable. Hence, to improve the manipulation controllability, identical twin bubbles with same sizes and resonant frequencies were employed. The identical gas bubbles were generated on a microfabricated chip comprising sharp tip-shaped electrodes by employing an electrochemical method, electrolysis, and controlling the applied voltage and time. Subsequently, the bubbles were sequentially transferred to the tips of a U-shaped rod coated with a hydrophobic layer to improve the surface adhesion. The force generated from the acoustically oscillating bubbles and their directions were analyzed under various acoustic excitation conditions by using high-speed images. Our results showed that the generated force was proportional to the bubble oscillation amplitude, whereas the direction of the force depended on the distance between a bubble and object. A steel ball (500 μm diameter) was used for investigating the force direction. When a bubble (600 μm diameter) was acoustically excited, the steel ball was pulled toward the oscillating bubble when the distance between the bubble and ball was short (<3 mm), whereas the steel ball was pushed away from the oscillating bubble when the distance was long (>3 mm). Finally, a fish egg (diameter: 1 mm) and glass beads (diameter: 100 μm) were experimentally manipulated using acoustically oscillating twin bubbles.
Source: Sensors and Actuators A: Physical, Available online 6 December 2011
Kyung Ho Lee, Jeong Hyun Lee, Jung Min Won, Kyehan Rhee, Sang Kug Chung
This paper describes a novel non-invasive micromanipulation technique that employs the cavitational microstreaming generated by acoustically oscillating twin bubbles. First, a single acoustically oscillating bubble was attached to the tip of a rod that was combined with a three-dimensional traverse system, and a fish egg (diameter: 1 mm) was then manipulated in an aqueous medium. Although the microstreaming generated by the single oscillating bubble was sufficiently strong to push and move the fish egg, the manipulation direction was uncontrollable. Hence, to improve the manipulation controllability, identical twin bubbles with same sizes and resonant frequencies were employed. The identical gas bubbles were generated on a microfabricated chip comprising sharp tip-shaped electrodes by employing an electrochemical method, electrolysis, and controlling the applied voltage and time. Subsequently, the bubbles were sequentially transferred to the tips of a U-shaped rod coated with a hydrophobic layer to improve the surface adhesion. The force generated from the acoustically oscillating bubbles and their directions were analyzed under various acoustic excitation conditions by using high-speed images. Our results showed that the generated force was proportional to the bubble oscillation amplitude, whereas the direction of the force depended on the distance between a bubble and object. A steel ball (500 μm diameter) was used for investigating the force direction. When a bubble (600 μm diameter) was acoustically excited, the steel ball was pulled toward the oscillating bubble when the distance between the bubble and ball was short (<3 mm), whereas the steel ball was pushed away from the oscillating bubble when the distance was long (>3 mm). Finally, a fish egg (diameter: 1 mm) and glass beads (diameter: 100 μm) were experimentally manipulated using acoustically oscillating twin bubbles.
Design of an Electromagnetic Imaging System for Weapon Detection based on GMR Sensor Arrays
04 December 2011, 21:44:28
Publication year: 2011
Source: Sensors and Actuators A: Physical, Available online 3 December 2011
Gui Yun Tian, Abdalrahman Al-Qubaa, John Wilson
Concealed weapon detection is one of the most challenging issues facing the security community. It has been shown that each weapon can have a unique fingerprint, which is a set of electromagnetic (EM) signals determined by its size, shape, and physical composition. Extracting the signature of each weapon is one of the major tasks in any detection system. This paper addresses the design of a detection system for the identification of conductive objects based on their response to EM fields. The system consists of commercial Walk-Through Metal Detector (WTMD) and a Giant Magneto-Resistive (GMR) sensor array has been designed and built. Also, this paper describes how to construct a two-dimensional image from the measured signals to be used for image processing purposes. The system validity is then checked based on two concepts: data validation and multiple object separation. Finally, initial experimental work on the automatic detection and classification of different metallic objects has been carried out. The promising results indicate the feasibility of using this EM imaging method to identify objects.
Source: Sensors and Actuators A: Physical, Available online 3 December 2011
Gui Yun Tian, Abdalrahman Al-Qubaa, John Wilson
Concealed weapon detection is one of the most challenging issues facing the security community. It has been shown that each weapon can have a unique fingerprint, which is a set of electromagnetic (EM) signals determined by its size, shape, and physical composition. Extracting the signature of each weapon is one of the major tasks in any detection system. This paper addresses the design of a detection system for the identification of conductive objects based on their response to EM fields. The system consists of commercial Walk-Through Metal Detector (WTMD) and a Giant Magneto-Resistive (GMR) sensor array has been designed and built. Also, this paper describes how to construct a two-dimensional image from the measured signals to be used for image processing purposes. The system validity is then checked based on two concepts: data validation and multiple object separation. Finally, initial experimental work on the automatic detection and classification of different metallic objects has been carried out. The promising results indicate the feasibility of using this EM imaging method to identify objects.
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