Acoustic Waves

This book introduces acoustic wave theories using a reader-friendly matrix-based linear algebra approach. It will enable the reader to take advantage of software tools such as MATLAB (commercial codes) and OCTAVE (open-source codes) to gain better and deeper understanding of the underlying physics quickly. In this aspect, this text can be regarded as a practical introduction of the acoustic wave theories in an easy-to-follow linear algebra format using matrix manipulations instead of an abstract approach relying on tensor manipulations. The book also uses case studies to demonstrate how the fundamentals on acoustic waves discussed throughout the book are applied in device designs and analyses such that the connections and interdependences between the underlying sciences and the observed behavior and performances can be better appreciated by the reader. To achieve this, all problems for illustrations, examples, case studies, and device analyses are developed and solved based on the mathematical foundations laid out in the book.

Written by an interdisciplinary group of experts from both industry and academia, Acoustic Wave Sensors provides an in-depth look at the current state of acoustic wave devices and the scope of their use in chemical, biochemical, and physical measurements, as well as in engineering applications. Because of the inherent interdisciplinary applications of these devices, this book will be useful for the chemist and biochemist interested in the use and development ofthese sensors for specific applications; the electrical engineer involved in the design and improvement of these devices; the chemical engineer and the biotechnologist interested in using these devices for process monitoring and control; and the sensor community at large. Provides in-depth comparison and analyses of different types of acoustic wave devices Discusses operating principles and design considerations Includes table of relevant material constants for quick reference Presents an extensive review of current uses of these devices for chemical, biochemical, and physical measurements, and engineering applications

Introducing the first, self-contained reference on acoustic waveform logging Acoustic measurements in boreholes were first made as a specialized logging technique in geological exploration, but recent advances have greatly expanded the potential applications of this technique. Acoustic Waves in Boreholes provides a thorough review of the theory and interpretation techniques needed to realize these applications, emphasizing the role of guided modes and critically refracted waves in determining the characteristics of recorded waveforms. Topics covered in this comprehensive volume include the seismic properties of rocks; propagation of axisymmetric waves along fluid-filled boreholes in isotropic rocks; and symmetric and nonsymmetric sources in isotropic, transversely isotropic, and porous, permeable formations in open and cased boreholes. Each chapter includes the theory of synthetic microseismogram computation, interpretation and data inversion techniques illustrated using computed seismograms, and case histories using experimental data. Appendices providing the mathematical formulation needed to compute microseismograms, with a single consistent notation used throughout, are also included in appropriate chapters. The wide range of geomechanical properties covered in this book will interest exploration geophysicists, reservoir engineers, civil engineers, geologists, and soil scientists.

Surface acoustic wave (SAW) devices are widely used in mobile communications, a rapidly evolving market. This book gives an overview on the latest SAW technologies with an emphasis on the design and simulation of devices, such as resonator-based devices employing the SH-type leaky SAW.

"Acoustic signal analysis is commonly used for non-invasive pipeline condition assessment and diagnosis. Considering that pipeline systems are made of different materials ranging from steel to polymers, the analysis method is also contingent on the vibroacoustic properties of the pipe wall material. In this compilation, an adaptive, locally defined time marching technique is presented to analyze wave propagation models. The methodology is based on two time integration parameters, namely [alpha] and [gamma]. Additionally, the authors present recent improvements in acoustic impedance methods to describe the transduction and propagation of guided elasticwaves in MEMS devices electrostatically actuated through thin air-gaps. The closing study focuses on the way in which the Lorentz force acting on a continuous medium from the side of the magnetic field has a significant effect on the behavior of magnetoacoustic waves"--

The concept of acoustic wave is a pervasive one, which emerges in any type of medium, from solids to plasmas, at length and time scales ranging from sub-micrometric layers in microdevices to seismic waves in the Sun's interior. This book presents several aspects of the active research ongoing in this field. Theoretical efforts are leading to a deeper understanding of phenomena, also in complicated environments like the solar surface boundary. Acoustic waves are a flexible probe to investigate the properties of very different systems, from thin inorganic layers to ripening cheese to biological systems. Acoustic waves are also a tool to manipulate matter, from the delicate evaporation of biomolecules to be analysed, to the phase transitions induced by intense shock waves. And a whole class of widespread microdevices, including filters and sensors, is based on the behaviour of acoustic waves propagating in thin layers. The search for better performances is driving to new materials for these devices, and to more refined tools for their analysis.

SAW devices are widely used in multitude of device concepts mainly in MEMS and communication electronics. As such, SAW based micro sensors, actuators and communication electronic devices are well known applications of SAW technology. For example, SAW based passive micro sensors are capable of measuring physical properties such as temperature, pressure, variation in chemical properties, and SAW based communication devices perform a range of signal processing functions, such as delay lines, filters, resonators, pulse compressors, and convolvers. In recent decades, SAW based low-powered actuators and microfluidic devices have significantly added a new dimension to SAW technology. This book consists of 20 exciting chapters composed by researchers and engineers active in the field of SAW technology, biomedical and other related engineering disciplines. The topics range from basic SAW theory, materials and phenomena to advanced applications such as sensors actuators, and communication systems. As such, in addition to theoretical analysis and numerical modelling such as Finite Element Modelling (FEM) and Finite Difference Methods (FDM) of SAW devices, SAW based actuators and micro motors, and SAW based micro sensors are some of the exciting applications presented in this book. This collection of up-to-date information and research outcomes on SAW technology will be of great interest, not only to all those working in SAW based technology, but also to many more who stand to benefit from an insight into the rich opportunities that this technology has to offer, especially to develop advanced, low-powered biomedical implants and passive communication devices.

Parametric array loudspeakers (PALs) are capable of generating highly directional audio beams from nonlinear interactions of intense airborne ultrasound waves. This unique capability holds great potential in audio engineering. This book systematically introduces the physical principles of acoustics waves generated by PALs, along with the commonly used and the state-of-the-art numerical models, such as the Westervelt model, the convolution directivity model, the Gaussian beam expansion method, and the spherical wave expansion method. The properties of sound fields generated by PALs are analyzed. Also analyzed are various phenomena including the reflection of acoustics waves generated by PALs from a surface, transmission through a thin partition, scattering by a rigid sphere, and propagation in rooms. Furthermore, the steering and focusing of acoustics waves generated by PALs and potential applications of PALs in active sound control are investigated. Finally, the implementation issues of hardware, signal processing techniques, measurement, and safety are discussed. The book is tailored to meet the needs of researchers in this field, as well as audio practitioners and acoustics engineers.