This article describes the design and manufacturing of a microfluidic chip, allowing for the actuation of a gas-liquid interface and of the neighboring fluid. A first way to control the interface motion is to apply a pressure difference across it. In this case, the efficiency of three different micro-geometries at anchoring the interface is compared. Also, the critical pressures needed to move ...

In a companion paper, a reduced model for propagation of acoustic waves in a cloud of inertial cavitation bubbles was proposed. The wave attenuation was calculated directly from the energy dissipated by a single bubble, the latter being estimated directly from the fully nonlinear radial dynamics. The use of this model in a mono-dimensional configuration has shown that the attenuation near the v...

Cones or wedges inserted between an ultrasonic transducer and a specimen enhances certain characteristics of the transducers. Such an arrangement is useful in that the transducer can be used for transmitting and receiving signals on a point ~or line! source, which can eliminate the undesirable aperture effect that makes the transducer blind to waves traveling in certain directions and to those ...

A flat transducer was constructed, using a 9-microm-thick PVDF (polyvinylidene fluoride) film for generation and detection of high-frequency ultrasonic waves, and used for measurements of the phase velocity of longitudinal waves traveling along the thickness direction in a very thin material. The transducer has a useful wideband frequency characteristic extending from 10 MHz to over 150 MHz. Me...

Cones and wedges inserted between an ultrasonic transducer and the specimen provide the transducer (circular or rectangular shape) with enhanced capability for point or line contact with the specimen. Such an arrangement is useful in that the transducer can be used for transmitting to and receiving from a point (or line) source, and that it can eliminate the undesirable aperture effect that mak...

This paper presents an Electronic Travel Aid (ETA) for visually impaired and blind people. This device enables a blind user to quickly and safely walk through obstacle cluttered and unknown environments with a combination of eye glasses and waist belt. The foremost innovation of this device is its ability to actively guide the user around obstacles in pursuit of a given target direction. Using ...

In this paper we compare the effectiveness of the time, wavelet and Hilbert Huang domain analysis of waveforms from a Non Destructive Test (NDT) equipment. The analysis of the signals from NDT systems is one of the most important activities since it allows to locate the actual defects. Very often the echoes traveling back to the sensors are superimposed with the signal from the transducer. We a...

A traveling wave-type ultrasonic motor (USM) has a self-locking characteristic due to a static frictional force present when its power supply is turned off, because its rotor is pressed strongly to the stator in the USM. We propose a pulse width modulation (PWM) method in consideration of this self-locking characteristic in order to control the motion of USM. The vibration waveform and the driv...