Application of a Weakly Non-Linear Analysis to the Analysis of Thermoacoustic Combustion Instabilities - new
D. Laera, S. M. Camporeale, G. Campa
Politecnico di Bari, Bari, Italy
Ansaldo Energia, Genoa, Italy
The thermoacoustic combustion instabilities are complex phenomena that may occur in steady flow combustion systems that are aboard of, e.g., rocket engines or gas turbines. The phenomena involve the interaction of chemical reactions with fluid-dynamic and propagation of pressure waves in the combustion chamber. Combustion instabilities may lead to a stable condition (known as “limit-cycle”) ...
M. Satthiyaraju , T. Ramesh ,
 National Institute of Technology, Tiruchirappalli, Tamil Nadu, India
The dynamic response of microcantilever, which is a simple microelectromechanical system (MEMS) structure, to sine wave excitation is studied using the vibrational speaker set up in the atmospheric damping. Microcantilever is fabricated using micro wire cut EDM process for high precision. Mostly silicon material is used for microsystems based structure. Here stainless steel was used and machined ...
H. Lissek, R. Boulandet, and M. Maugard
Ecole Polytechnique Federale de Lausanne
An \"electroacoustic absorber\" is a loudspeaker, used as an absorber of sound, which acoustic impedance can be varied by electrical means. This can be achieved either by plugging passive shunt electric networks at the loudspeaker terminals (“shunt loudspeakers”) or by feeding back the loudspeaker with a voltage proportional to acoustic quantities, such as sound pressure and diaphragm normal ...
Investigation on Sensor Fault Effects of Piezoelectric Transducers on Wave Propagation and Impedance Measurements
I. Buethe, C.-P. Fritzen
University of Siegen, Institute of Mechanics and Control Engineering-Mechatronics, Siegen, Germany
For active Structural Health Monitoring (SHM), one popular sensor type is the piezoelectric wafer active sensor (PWAS) due to its multi-purpose application as actuator and sensor and its low cost. It is used to generate a wave field, which interacts with the structure and is recorded by a second set of PWASs. This method is called acousto ultrasonics. The change in wave field from transducer ...
A. Castellano, P. Foti, A. Fraddosio, S. Marzano, M.D. Piccioni, D. Scardigno
DICAR, Politecnico di Bari, Bari, Italy
Introduction: Improving the capability of nondestructive evaluations requires the analysis of suitable models dealing with the physical and mechanical phenomena involved in the experiments. For example, ultrasonic tests may be a powerful, fast and effective method for nondestructive characterization of mechanical properties of materials. This requires the study of the related elastodynamic ...
Clemson University, Clemson, SC, USA
Surface acoustic wave (SAW) devices are commonly used as wireless filters, resonators, and sensors. The confinement of acoustic energy near the surface of a piezoelectric substrate in a SAW sensor makes it highly sensitive for discerning surface perturbation. As sensors, SAW devices have the potential to provide a high-performance sensing platform with capabilities of remote and high-temperature ...
R. Langkemper , R. Külls , J. Wilde , S. Nau , S. Schopferer ,
 Fraunhofer-Institut für Kurzzeitdynamik, Ernst-Mach-Institut, EMI, Freiburg, Germany
 Albert-Ludwigs-Universität Freiburg, Institut für Mikrosystemtechnik, Freiburg, Germany
Acceleration is an important quantity to be measured in high-speed dynamics. A new piezoresistive sensor for the measurement of high-amplitude, short-duration transient accelerations of up to 100,000 g has been developed at the Fraunhofer EMI. Its figure of merit (sensitivity x resonance frequency²) is about one order of magnitude higher than that of comparable state-of-the-art sensors. ...
H. Lin , N. Sun , N. X. Sun ,
 W.M. Keck Laboratory for Integrated Ferroics, ECE Department, Northeastern University, Boston, MA, USA
RF NEMS Magnetoelectric (ME) Sensor with a ferromagnetic (FeGaB)/ piezoelectric (AlN) thin film heterostructure is simulated, fabricated and measured in this work. To analyze the response of the ME structures, the coupling between the magnetic, elastic and electric field in the two different magnetostrictive and piezoelectric effects should be taken into consideration. Simulations with FEM ...
M. A. B. Andrade , N. Pérez , J. C. Adamowski ,
 Instituto de Física, Universidade de São Paulo, São Paulo, SP, Brasil
 Centro Universitario de Paysandú, Universidad de la República, Paysandú, Uruguai
 Departamento de Engenharia Mecatrônica e Sistemas Mecânicos, Escola Politécnica, Universidade de São Paulo, São Paulo, SP, Brasil
Este trabalho apresenta a simulação numérica de um sistema de levitação acústica para manipulação de partículas em ar. O sistema de levitação consiste de dois transdutores de ultrassom e um refletor de face plana. Através da simulação é calculado o potencial da força de radiação acústica que atua numa esfera. Os resultados da simulação são verificados experimentalmente através da comparação da ...
C. R. Pérez , J. J. Santiago-Avilés ,
 Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA, USA
 Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, USA
Sensorineural hearing loss is the most common sensory deficit in the world, and within this category damage or loss of the primary sensory cells of the inner ear, known as hair cells is the most common cause . Partial hearing loss is addressed by the use of hearing aids, electronic devices that greatly amplify sound directly into the user's ear, but for more severe cases cochlear implants are ...