Gaussian random waves in elastic media

Similar to the Berry conjecture of quantum chaos we consider elastic analogue which incorporates longitudinal and transverse elastic displacements with corresponding wave vectors. Based on that we derive the correlation functions for amplitudes and intensities of elastic displacements. Comparison to numerics in a quarter Bunimovich stadium demonstrates excellent agreement.Comment: 4 pages, 4 figure

Optimization of Training Sets For Neural-Net Processing of Characteristic Patterns From Vibrating Solids

An artificial neural network is disclosed that processes holography generated characteristic pattern of vibrating structures along with finite-element models. The present invention provides for a folding operation for conditioning training sets for optimally training forward-neural networks to process characteristic fringe pattern. The folding pattern increases the sensitivity of the feed-forward network for detecting changes in the characteristic pattern The folding routine manipulates input pixels so as to be scaled according to the location in an intensity range rather than the position in the characteristic pattern

Current and vorticity auto correlation functions in open microwave billiards

Using the equivalence between the quantum-mechanical probability density in a quantum billiard and the Poynting vector in the corresponding microwave system, current distributions were studied in a quantum dot like cavity, as well as in a Robnik billiard with lambda=0.4, and an introduced ferrite cylinder. Spatial auto correlation functions for currents and vorticity were studied and compared with predictions from the random-superposition-of-plane-waves hypothesis. In addition different types of vortex neighbour spacing distributions were determined and compared with theory.Comment: PTP-LaTeX, 10 pages with 6 figures submitted to Progress of Theoretical Physics Supplemen

Improved Calculation of Vibrational Mode Lifetimes in Anharmonic Solids - Part I: Theory

We propose here a formal foundation for practical calculations of vibrational mode lifetimes in solids. The approach is based on a recursion method analysis of the Liouvillian. From this we derive the lifetime of a vibrational mode in terms of moments of the power spectrum of the Liouvillian as projected onto the relevant subspace of phase space. In practical terms, the moments are evaluated as ensemble averages of well-defined operators, meaning that the entire calculation is to be done with Monte Carlo. These insights should lead to significantly shorter calculations compared to current methods. A companion piece presents numerical results.Comment: 18 pages, 3 figure

Measurement of dynamic full-field internal stresses through surface laser Doppler vibrometry

We present a method for evaluating internal dynamic stresses in a solid vibrating body from measurements of surface motion. The method relies on the same mathematics as boundary element method: A boundary reciprocity integral represents interior motion as a surface integral of boundary motion times the Green’s function. The surface motions are measured with a laser vibrometer rather than simulated, giving a direct measurement of internal motions and internal dynamic stresses. Experimental results on a flexing beam demonstrate that stresses measured in this fashion match those calculated from elementary theory

Sketching sonic interactions by imitation-driven sound synthesis

Sketching is at the core of every design activity. In visual design, pencil and paper are the preferred tools to produce sketches for their simplicity and immediacy. Analogue tools for sonic sketching do not exist yet, although voice and gesture are embodied abilities commonly exploited to communicate sound concepts. The EU project SkAT-VG aims to support vocal sketching with computeraided technologies that can be easily accessed, understood and controlled through vocal and gestural imitations. This imitation-driven sound synthesis approach is meant to overcome the ephemerality and timbral limitations of human voice and gesture, allowing to produce more refined sonic sketches and to think about sound in a more designerly way. This paper presents two main outcomes of the project: The Sound Design Toolkit, a palette of basic sound synthesis models grounded on ecological perception and physical description of sound-producing phenomena, and SkAT-Studio, a visual framework based on sound design workflows organized in stages of input, analysis, mapping, synthesis, and output. The integration of these two software packages provides an environment in which sound designers can go from concepts, through exploration and mocking-up, to prototyping in sonic interaction design, taking advantage of all the possibilities of- fered by vocal and gestural imitations in every step of the process

The Sound Design Toolkit

The Sound Design Toolkit is a collection of physically informed sound synthesis models, specifically designed for practice and research in Sonic Interaction Design. The collection is based on a hierarchical, perceptually founded taxonomy of everyday sound events, and implemented by procedural audio algorithms which emphasize the role of sound as a process rather than a product. The models are intuitive to control \u2013 and the resulting sounds easy to predict \u2013 as they rely on basic everyday listening experience. Physical descriptions of sound events are intentionally simplified to emphasize the most perceptually relevant timbral features, and to reduce computational requirements as well

Потери энергии в пьезокерамических резонаторах и их влияние на характеристики колебаний

Стаття присвячена аналізу сучасних досягнень у проблемі втрат енергії в п’єзокерамічних резонаторах. Паралельно презентується нова проста методика експериментального визначення коефіцієнтів втрат енергії та зв’язку і подається думка автора, чому механічна добротність на резонансі та антирезонансі є різною. Причина полягає у „затиснутій” ємності та у величині коефіцієнта електромеханічного зв’язку. Чим кращий електромеханічний зв'язок, тим дужче „затиснута” ємність і тим вищий її вплив на антирезонансну частоту й добротність.This paper is devoted to analyze of the modern achievements in energy loss problem for piezoceramic resonators. In parallel a new simple methodic of an experimental determination of energy losses and coupling coefficients is presented and author’s opinion why mechanical quality is different on resonance and anti-resonance is gave. The reason lies in “clamped” capacity and electromechanical coupling factor’s value. The better electromechanical coupling the stronger capacity “clamping” and the higher its influence on anti-resonant frequency and quality.Статья посвящена анализу современных достижений в проблеме потерь энергии в пьезокерамических резонаторах. Параллельно презентуется новая простая методика экспериментального определения коэффициентов потерь энергии и святи и приводится мнение автора, почему механическая добротность на резонансе и антирезонансе разная. Причина состоит в «зажатой» емкости и в величине коэффициента электромеханической связи. Чем лучше электромеханическая связь, тем сильнее «зажата» емкость и тем выше ее влияние на антирезонансную частоту и добротность