Sound waves are very convenient for the investigation of
all wave phenomena with the exception of polarization. They are
particularly useful in connection with microwaves because the
latter's wave length can be easily duplicated with sound waves,
making it possible to obtain the same diffraction pattern for
both when confronted...
In these tests, phenolic constituents from bark of Shasta red fir were found ineffective as stiffening agents for corrugating medium. Other means of application, however, may be effective.
Gum from inner bark of Shasta red fir was not so effective as a beater additive as was locust bean gum, but...