Speed of Sound
If rod diameter < wavelength:
Board thickness < wavelength:
The higher the bulk density the higher the speed of sound
Speed of sound longitudinal > radial > tangential
The higher the fibre angle the lower E-modulus the lower the speed
Higher frequency of sound leads to higher speed
Sound absoption S
non reflected power / impacting acoustic power
The higher the porosity the higher the absoption
Sound isolation index
impacting acoustic power front / impacting acoustic power back
Combination of dissipation and reflection
The higher the sound frequency and mass of material the higher the sound isolation
Accoustic emisson
To detect microfracture already below maximum load
Used to trace the state of wooden buildings
The highe rthe moisture content the lower the sum of impulses
Refractive index
speed of light in vacuum / speed of light in material
Transparent wood
Refractive index of delignified wood: 1.53
Fill liquids with different RI to matrix
Goal: make transparent wood
MMa infiltraed wood
Anisotropic wood light interaction
Light propagates preferably in fiber direction —> cellulose as liht guiding
In transparent wood: polymer filled lumina as wave guide
Anisotropic light scattering along tangential/radial direction
Transparent wood for windows
diffuse light
low thermal conductivity
less brittle than glass
sustainable
Luminescent Wood
Delignified, PMMA impregnated $FLuorescence: silicon quantum dots
Zuletzt geändertvor einem Jahr
