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We apply THz imaging technology to evaluate fire damage to a variety of carbon fiber composite samples. The majority of carbon fiber materials have polarization-dependent reflectivities in the THz frequency range, and we show how the polarization dependence changes versus the burn damage level. Additionally, time domain information acquired through a THz time-domain spectroscopy (TDS) system provides further information with which to characterize the damage. The technology is discussed in terms of non-destructive testing applications to the defense and aerospace industries.

Microwave absorption properties (MAP) of manganese soft spinel ferrite (MnFe2O4) nanoparticles (MSF NPs) mixed with multi-walled carbon nanotubes (MWCNTs) and molded as toroid-shaped pellets were experimentally studied using a coaxial line technique in the frequency range of 2-18 GHz. We used the coaxial line technique because of the smaller sample size, a wider frequency range, and a uniform cross section. The MAP were derived from the measured constitutive parameters, according to the transmission line theory. The results indicate that MWCNTs blended with ferrite nanoparticles represent a promising choice for broadband microwave absorbing materials.