Sökning: "Acoustic waves"

Visar resultat 16 - 20 av 124 avhandlingar innehållade orden Acoustic waves.

1. 16. Sound Field Design for Transducer Array-Based Acoustic Levitation

   Författare :Carl Andersson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Nonlinear Acoustics; Sound Field Design; Transducer Arrays; Acoustic Levitation; Numerical Optimization;

   Sammanfattning : Acoustic levitation is a technique where sound waves are used to hold an object at a designated position, suspending it against other external forces and keeping it stable in the desired position. Transducer arrays are an arrangement of many loudspeaker elements, tuned such that the array creates a sound field that is too complicated for the individual elements to produce on their own. LÄS MER

3. 17. Nonlinear Interaction Between Ultrasonic Waves and Cracks and Interfaces

   Författare :Milan Poznic; Leif Kari; Bruce Drinkwater; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ultrasonic waves; crack; modulation; rough interface; partially closed; surface-breaking; fluid-filled; Acoustics; Akustik;

   Sammanfattning : The subject of this thesis is the development of new ultrasound inspection techniques for detection of cracks that are smaller than the wavelength of the inspecting wave and the characterization of cracks in fluid-filled pipes as either surface-breaking or subsurface. The spectrum of the scattered field of a partially closed crack comprises harmonic components not expected to be found in the case of linear scatterers such as pores or inclusions. LÄS MER

4. 18. Acoustic Platform for MXene Synthesis and Electrochemical Behaviour of i-MXenes in Aqueous Electrolytes

   Författare :Ahmed El Ghazaly; Johanna Rosén; Ahmed Etman; Husam N. Alshareef; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Surface Acoustic Waves; MXene; i-MXene; Supercapacitor;

   Sammanfattning : Climate Change is believed to be the greatest global challenge and on its forefront is the topic of energy. While being of extreme importance, debates over energy have become a normality. LÄS MER

5. 19. On multilayered system dynamics and waves in anisotropic poroelastic media

   Författare :Juan Pablo Parra Martinez; Peter Göransson; Olivier Dazel; Jacques Cuenca; Wennhage Wennhage; Camille Perrot; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; poroelastic media; anisotropy; plane waves; multilayered systems; dynamics; acoustics; optimisation; matériaux poro-visco-élastique; anisotropie; ondes planes; panneaux multicouches; dynamique; acoustique; optimisation; Poroelastiska material; anisotropi; planvågor; flerskiktssystem; dynamik; akustik; optimering; Vehicle and Maritime Engineering; Farkostteknik;

   Sammanfattning : The mechanical and acoustic anisotropy of media is a governing factor in the behaviour of multilayered systems including such media. The understanding of the mechanisms conditioning the dynamic behaviour of multilayered systems is of paramount importance. LÄS MER

7. 20. Lamb wave evaluation of concrete plates

   Författare :Oskar Tofeldt; Teknisk geologi; []
   Nyckelord :Lamb waves; guided waves; impact-echo; concrete; non-destructive evaluation;

   Sammanfattning : This thesis is about the application of Lamb waves for non-destructive evaluation of plate-like concrete structures under one-sided access test condition using a portable equipment consisting of an accelerometer and impact hammer. With this type of equipment and based on array signal processing, the impact-echo (IE) method can be extended with measurements of surface waves; this extension allows an evaluation with Lamb waves. LÄS MER