Text this: Stress waves in functionally gradient materials and its use for material characterization

  ______    ______   _    _    _    _     _____   
 /_____//  /_   _// | || | || | || | ||  / ____|| 
 `____ `    -| ||-  | || | || | || | || / //---`' 
 /___//     _| ||_  | \\_/ || | \\_/ || \ \\___   
 `__ `     /_____//  \____//   \____//   \_____|| 
 /_//      `-----`    `---`     `---`     `----`  
 `-`