The strength development of young masonry mortar and prism is studied through measuring the electrical properties of hydrating mortar by using TWIN-tape capacitance sensor. The dielectric properties over the frequency range of 10 kHz to10 MHz varies during hydration of mortar, providing a means for monitoring the strength development. This investigation confirms that the lower frequencies (less than 100 kHz) are very efficient in monitoring hydration of mortar. In addition, wireless sensing electronics is employed to monitor the strength gain process of young masonry prisms. Moreover, the freezing and thawing temperatures of masonry mortar and prism are identified by using three different techniques. Furthermore, the strength gain process of mortar is investigated at cold ambient temperatures, i.e. ambient temperature below 5ºC, by using dielectric measurements. This investigation reveals that the mortar gains strength at temperatures as low as 0ºC, whereas it partially freezes at -1º c and completely freezes at -2ºC.

Thesis advisor: Michael J. Naughton / Surface plasmon polaritons (SPPs) are hybridized quasiparticles of photons and electron density waves. They are confined to propagate along metal-dielectric interfaces, and decay exponentially along the direction perpendicular to the interfaces. In the past two decades, SPPs have drawn intensive attention and undergone rapid development due to their potential for application in a vast range of fields, including but not limited to subwavelength imaging, biochemical/biomedical sensing, enhanced light trapping for solar cells, and plasmonic logic gates. These applications utilize the following intrinsic properties of SPPs: (1) the wavelength of SPPs is shorter (and can be much shorter) than that of free photons with the same frequency; (2) the local electric field intensity associated with SPPs can be orders of magnitude larger than that of free photons; and (3) SPPs are bound to metal surfaces, and are thus easily modulated by the geometry of those surfaces. Here, we present studies on SPPs along metal surfaces with novel structures, including the following: (1) SPP standing waves formed along circular metal surfaces that lead to a "plasmonic halo" effect; (2) directional reflectionless conversion between free photons and SPPs in asymmetric metal-insulator-metal arrays; and (3) broadband absorbance enhancement of embedded metallic nanopatterns in a photovoltaic absorber layer. These works may prove useful for new schemes for SPP generation, plasmon-photon modulation, ultrasensitive dielectric/bio sensing, and high efficiency thin film solar cells. / Thesis (PhD) — Boston College, 2014. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Physics.