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<p>In this thesis, we discuss the study and realization of surface plasmon polaritons (SPPs) and their devices. Plasmonics is the emerging field that will help technologies advance further into the nano-scale without the concern for delays or size limitations. SPPs are a more advanced field of photonics as they use metals instead of the semiconductors or insulators used in optics. They operate at frequencies in the light and near infrared spectrum, as this range produces their unique characteristics. Plasmonics possess the miniaturization of electronics and the speed of photonics. They do not suffer from both the delays in nano-electronics, and the size limitations faced in optics. In this thesis, we present the optimization of plasmonic slit arrays by designing the parabolic phase profile of the array. Moreover, we present a novel multilevel plasmonic coupler that will aid in the realization of 3-D plasmonic chips, as well as quadrature modulation. The theory, procedures, and results are all presented and discussed.</p> / Master of Applied Science (MASc)

This paper presents 3-D face modeling with head pose and depth information estimated from a 2-D query face image. Many recent approaches to 3-D face modeling are based on a 3-D morphable model that separately encodes the shape and texture in a parameterized model. The model parameters are often obtained by applying statistical analysis to a set of scanned 3-D faces. Such approaches tend to depend on the number and quality of scanned 3-D faces, which are difficult to obtain and computationally intensive. To overcome the limitations of 3-D morphable models, several modeling techniques from 2-D images have been proposed. We propose a novel framework for depth estimation from a single 2-D image with an arbitrary pose. The proposed scheme uses a set of facial features in a query face image and a reference 3-D face model to estimate the head pose angles of the face. The depth information of the subject at each feature point is represented by the depth information of the reference 3-D face model multiplied by a vector of scale factors. We use the positions of a set of facial feature points on the query 2-D image to deform the reference face dense model into a person specific 3-D face by minimizing an objective function. The objective function is defined as the feature disparity between the facial features in the face image and the corresponding 3-D facial features on the rotated reference model projected onto 2-D space. The pose and depth parameters are iteratively refined until stopping criteria are reached. The proposed method requires only a face image of arbitrary pose for the reconstruction of the corresponding 3-D face dense model with texture. Experiment results with USF Human-ID and Pointing'04 databases show that the proposed approach is effective to estimate depth and head pose information with a single 2-D image. / Electrical and Computer Engineering

Root biomass accounts for about 25% of the carbon storage in mid-latitude forests. Estimation of root biomass for carbon cycling studies requires either direct measurement by excavation of root systems, or remote measurement using ground penetrating radar (GPR) or other geophysical methods. This study evaluated the ability of a 2-GHz multi-channel GPR system (IDS Hi-BrigHT) to detect and map white pine roots in managed forest near Turkey Point, southern Ontario. The GPR system employed eight dual-polarized antenna pairs separated at 10 cm intervals. GPR data were acquired as overlapping swaths (2 cm line spacing, 0.4 cm inline) across a 25-m2 test site (TP74-R) containing a juvenile white pine tree. Radargrams were processed to full 3-D radar volumes for time slicing and interpretation of root architecture and comparison with the excavated root network. Radargram signal processing was successful in suppressing airwave and other background noise and improved the detection of root diffractions on radargrams. The majority of roots were found in the rooting zone at a depth of 5-40 cm. Roots as small as 0.5 cm were detected with the 2-GHz frequency, but many roots <1.5 cm diameter could not be detected as continuous root structures. Root detection was strongly dependent on root orientation; large, coarse roots (>3-5 cm) were imaged as continuous root segments when oriented perpendicular to GPR profiles. Roots intersecting GPR profiles at angles <30-45 degrees were either imaged incompletely or not detected on radargrams. The highest rate of root detection was achieved with horizontally polarized (HH) antennas (dipole axis parallel with the root structures). Isosurface root models constructed from the Hilbert-transformed radargrams allowed mapping of the 3-D dimensional root architecture for large (> 3-5 cm diameter) roots. Isosurface models provide a means for estimating the coarse root volume for large roots and could be employed in future work to monitor temporal changes in root biomass by repeat survey at the same measurement site. Radargram signal processing was successful in suppressing airwave and other background noise and improved the detection of root diffractions on radargrams. The majority of roots were found in the rooting zone at a depth of 5-40 cm. Roots as small as 0.5 cm were detected with the 2-GHz frequency, but many roots <1.5 cm diameter could not be detected as continuous root structures. Many roots were not detected due to dependence of root reflection amplitude on root orientation. Roots oriented at >30-45 degrees to the survey swaths were imaged incompletely or not detected. Most large coarse roots (>5 cm diameter) were mapped as continuous structures when the root orientation was either parallel to, or perpendicular to the GPR transects. The highest rate of root detection was achieved with the horizontally polarized (HH) antennas, with the dipole axis perpendicular to the root structures. Isosurface root models constructed from the Hilbert-transformed radargrams allowed mapping of the 3-D dimensional root architecture for large (> 3-5 cm diameter) roots. The isosurface models provide a means for estimating the coarse volume and belowground biomass but further work is required to improve 3-D image resolution to allow detection of the entire root network. The method could be employed to measure the temporal changes in root biomass by conducting repeat surveys at the same measurement site. Radargram signal processing was successful in suppressing airwave and other background noise and improved the detection of root diffractions on radargrams. The majority of roots were found above a depth of 40 cm with the root zone being detected at a depth of10-15 cm. Roots as small as 0.5 cm were detected with the 2-GHz frequency, but many roots <1.5 cm diameter could not be detected as continuous root structures. Many roots were not detected due to dependence of root reflection amplitude on root orientation. Roots oriented at >30-45 degrees to the survey swaths were imaged incompletely or not detected. Most large coarse roots (>5 cm diameter) were mapped as continuous structures when the root orientation was either parallel to, or perpendicular to the GPR transects. The highest rate of root detection was achieved with the horizontally polarized (HH) antennas, with the dipole axis perpendicular to the root structures. Isosurface root models constructed from the Hilbert-transformed radargrams allowed mapping of the 3-D dimensional root architecture for large (> 3-5 cm diameter) roots. The isosurface models provide a means for estimating the coarse volume and belowground biomass but further work is required to improve 3-D image resolution to allow detection of the entire root network. / Thesis / Master of Science (MSc) / Forests play an important role in the global carbon cycle by removing carbon from the Earth’s atmosphere and storing it in tree tissues as biomass. Estimation of the amount of biomass and carbon stored in forests is critical to predictive climate change models, and increasingly employs remote sensing methods to detect both the above ground biomass (e.g. leaves, tree branches) and the belowground carbon in the tree root system. Measurement of the belowground biomass is most difficult, as it cannot be directly observed without destructive excavation of the tree root system. This study investigated the application of new technology, multi-channel ground penetrating radar (GPR), for mapping tree root systems. The GPR system (IDS Hi-BrigHT) employs ‘swath mapping’ using high frequency pulsed radio waves and multiple transmitting and receiving antennas to produce detailed maps of roots structure. The GPR capabilities were evaluated at a test site at the Turkey Point Flux Station (TPFS) in southern Ontario. The root system of a juvenile white pine tree (20-30 cm diameter) was swath mapped over a 25-m2 area with a line spacing of 2 cm. The GPR data were processed to produce a 3-dimensional radar volume, which can be ‘sliced’ in various orientations to reveal the root structure. The time slice maps show that roots as small as 1-cm can be detected and roots larger than 3 cm in diameter can be mapped as continuous root segments.

Chondrozyten stellen die zelluläre Komponente von hyalinem Knorpel dar, der die Gelenkflächen diarthrotischer Gelenke bedeckt. Über die perizelluläre Matrix (PZM) sind sie mit der extrazellulären Matrix des Knorpelgewebes, die im Wesentlichen aus Wasser, Kollagen-Typ-II (Koll-II) und Glykosaminoglykan (GAG) gebildet wird, verbunden. Die PZM gilt als wichtiges modulatorisches und protektives Element in der Signal- und Mechanotransduktion sowie für die Homöostase innerhalb des Knorpelgewebes. Degenerative und inflammatorische Prozesse führen zu irreparablen Schäden der Gewebearchitektur und -funktionalität. Die Regenerative Medizin strebt den Ersatz destruierter Gelenkflächen durch mittels Tissue Engineering hergestellten Neoknorpel an. 3D-Bioprinting gilt hier als attraktive Methode, nimmt jedoch über Scherkräfte während des Druckvorgangs auch schädigenden Einfluss auf das Überleben oder die Funktionalität der Zellen. Zielsetzung dieser Arbeit war es, den möglichen protektiven Einfluss der PZM während des Druckvorgangs zu untersuchen. Aus porcinem Frischknorpel isolierte Chondrozyten wurden nach cast bzw. 3D-Bioprinting in Agarose-Biotinte hinsichtlich ihres Überlebens und ihrer Syntheseleistung von knorpelspezifischem Koll-II und GAG untersucht. Chondrozyten ohne PZM wurden mit Chondrozyten verglichen, die nach enzymatischer Isolation noch perizellulär Kollagen-Typ-VI als Marker der PZM aufwiesen. Chondrozyten mit PZM zeigten allgemein eine stärkere Produktion von Koll-II als Chondrozyten ohne PZM. Nach 3D-Bioprinting konnte für Chondrozyten ohne PZM eine signifikant geringere Produktion von GAG nachgewiesen werden als in der cast-Vergleichsgruppe, während dies für Chondrozyten mit PZM nicht gezeigt werden konnte. Der gezeigte protektive Einfluss der PZM gegenüber Scherkräften während des Druckvorgangs eröffnet neue Methoden für das Cartilage Tissue Engineering. Weitere Untersuchungen sind notwendig, um dies zu bestätigen und die Translation in die klinische Forschung ermöglichen. / Chondrocytes are the cellular component of the hyaline cartilage that lines the articular surfaces of diarthrotic joints. They are bound to the extracellular matrix of the cartilage tissue by the pericellular matrix (PCM), which consists mainly of water, collagen type II (coll-II) and glycosaminoglycan (GAG). PCM is considered to be an important modulatory and protective element in signalling, mechanotransduction and homeostasis within cartilage tissue. Degenerative and inflammatory processes cause irreparable damage to tissue architecture and functionality. Regenerative medicine aims to replace damaged joint surfaces with neocartilage produced by tissue engineering. 3D bioprinting is considered to be an attractive method for this purpose, but also has a detrimental effect on the survival or functionality of the cells due to shear forces during the printing process. The aim of this study was to investigate the potential protective effect of PZM during the printing process. Chondrocytes isolated from fresh porcine cartilage were analysed after casting or 3D bioprinting in agarose bioprinting for their survival and their ability to synthesise cartilage-specific Coll-II and GAG. Chondrocytes without PCM were compared with chondrocytes that still had pericellular collagen type VI as a marker of PCM after enzymatic isolation. Chondrocytes with PCM generally showed a higher production of Coll-II than chondrocytes without PCM. After 3D bioprinting, chondrocytes without PCM showed significantly lower GAG production than the control group, whereas chondrocytes with PCM did not. The demonstrated protective effect of PCM against shear forces during the printing process opens up new possibilities for cartilage tissue engineering. Further studies are needed to confirm this and to enable translation into clinical research.

We present a three-dimensional (3-D) optical image matching technique and location extraction techniques of matched 3-D objects for optical pattern recognition. We first describe the 3-D matching technique based on two-pupil optical heterodyne scanning. A hologram of the 3-D reference object is first created and then represented as one pupil function with the other pupil function being a delta function. The superposition of each beam modulated by the two pupils generates a scanning beam pattern. This beam pattern scans the 3-D target object to be recognized. The output of the scanning system gives out the 2-D correlation of the hologram of the reference object and that of the target object. When the 3-D image of the target object is matched with that of the reference object, the output of the system generates a strong correlation peak. This theory of 3-D holographic matching is analyzed in terms of two-pupil optical scanning. Computer simulation and optical experiment results are presented to reinforce the developed theory. The second part of the research concerns the extraction of the location of a 3-D image matched object. The proposed system basically performs a correlation of the hologram of a 3-D reference object and that of a 3-D target object, and hence 3-D matching is possible. However, the system does not give out the depth location of matched 3-D target objects directly because the correlation of holograms is a 2-D correlation and hence not 3-D shift invariant. We propose two methods to extract the location of matched 3-D objects directly from the correlation output of the system. One method is to use the optical system that focuses the output correlation pattern along depth and arrives at the 3-D location at the focused location. However, this technique has a drawback in that only the location of 3-D targets that are farther away from the 3-D reference object can be extracted. Thus, in this research, we propose another method in which the extraction of a location for a matched 3-D object is possible without the aforementioned drawback. This method applies the Wigner distribution to the power fringe-adjusted filtered correlation output to extract the 3-D location of a matched object. We analyze the proposed method and present computer simulation and optical experiment results. / Ph. D.

The dynamic characteristics of hydrogen and ionic bonding contributes to the reversible properties of acrylic polymers, opening new avenues for designing materials with mechanical strength and processability. These non-covalent interactions function as physical crosslinks, which provide enhanced structural and mechanical integrity to acrylic block copolymers. The strong hydrogen bonding or ionic interaction also directs self-assembly to hierarchical microstructures, which enables many applications including thermoplastic elastomers and energy storage devices. Inspired by complementary hydrogen bonding interactions between nucleobase pairs in DNA, a series of bioinspired nucleobase-acrylate monomers such as adenine acrylate (AdA), thymine acrylate (ThA), cytosine acrylate (CyA) were designed, whose synthesis were afforded by aza-Michael addition. Among those nucleobases, cytosine arises as a unique category. It is not only able to self-associate via weak hydrogen bonds, but also forms quadruple hydrogen-bond bearing units (ureido-cytosine) when functionalized with isocyanates. Reversible addition-fragmentation chain transfer polymerization (RAFT) yielded acrylic ABA triblock copolymers with CyA external hard blocks. A subsequent post-functionalization using hexyl-isocyanate generated the corresponding ureido-cytosine acrylate(UCyA)-containing triblock copolymers. The self-complementary quadruple hydrogen bonding in the UCyA polymers achieved a broader service temperature window, while the alkyl chain ends of UCyA units allowed tunability of the mechanical strength to apply as thermoplastic elastomers. In addition, quadruple hydrogen bonding induced stronger propensity of self-assembly and denser packing of the polymers, which contributed to a well-defined ordered morphology and enhanced resistance to moisture uptake. A facile 2-step synthesis provided doubly-charged styrenic DABCO salt monomer(VBDC₁₈BrCl) containing an octadecyl tail. RAFT polymerization allowed the preparation of DABCO ABA block copolymers with defined molecular weights and low polydispersity. Thermal analysis revealed a melting transition of the VBDC₁₈BrCl block copolymer resulting from the side-chain crystallization of the long alkyl tail. Systematic mechanical comparisons between DABCO salt-containing copolymers and the corresponding singly-charged polymer controls demonstrated superior mechanical properties attributable to a stronger ionic interaction between the doubly-charged groups. Morphological characterizations revealed a well-ordered lamellar microstructure and a unique three-phase morphology of the DABCO block copolymers, which involve a soft phase, a hard phase, and an ionic aggregates domain dispersed within the hard domain. / Master of Science