The New Jersey Institute of Technology's
Electronic Theses & Dissertations Project

Title:	Non-destructive evaluation of agglomerated cork products using THz spectroscopy and imaging
Author:	Zhang, Han
View Online:	njit-etd2012-013 (ix, 44 pages ~ 3.0 MB pdf)
Department:	Department of Physics
Degree:	Master of Science
Program:	Applied Physics
Document Type:	Thesis
Advisory Committee:	Federici, John Francis (Committee chair) Zhou, Tao (Committee member) Barat, Robert Benedict (Committee member) Brisson, Caroline (Committee member)
Date:	2012-01
Keywords:	Agglomerated cork products THz spectroscopy and imaging
Availability:	Unrestricted
Abstract:	Terahertz spectroscopy from 0.15 to 0.3 THz is used to classify agglomerated cork products. Position dependent scattering of radiation allows one to image the internal structure of cork products. Previous studies have focused on natural (solid) cork stoppers. In this study, the feasibility of classifying agglomerated cork structures using THz imaging and spectroscopy is investigated. Both THz images and spectra are used to classify the agglomerated cork samples. Classification of the samples used three methods: visible examination of the THz images, statistical analysis of the pixel intensities, and a polynomial regression of the THz spectral data averaged over all pixels. Three types of agglomerated corks are studied: large cork granule, small cork granule, and twin-top technical corks. Classification based on both THz absorbance and time-delay enables the classification of the three cork types. Eventually, the measured THz properties and classifications will be correlated with the corks’ measured oxygen transfer rate, which is an important performance criterion.