Made available in DSpace on 2014-06-11T19:22:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-08-30Bitstream added on 2014-06-13T19:07:52Z : No. of bitstreams: 1 beneditti_ca_me_prud.pdf: 3065249 bytes, checksum: b10d04069c7a91011443ee9fcf72ab9c (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Sensores ópticos são amplamente utilizados para mapeamento da cobertura da terra em escala local e pequenas regiões, com uma ampla variedade de aplicações, incluindo planejamento urbano, inventario agrícola e florestal, gerenciamento de bacias hidrográficas e monitoramento ambiental. Mapeamento de cobertura da terra com dados da banda L SAR tem focado primariamente em florestas e área úmidas de regiões tropical e boreal, com ênfase no monitoramento de desmatamento tropical e reflorestamento. No inicio de 2006, aquisições sistemáticas do ALOS PALSAR tem fornecido conjunto de dados multisazonais com alta resolução (12,5m), com potencial para substituir ou complementar os conjuntos de dados ópticos para mapeamento de cobertura da terra em regiões que a cobertura de nuvens é menos problemática, mas ainda um limitante para a variação sazonal da cobertura da terra. Este estudo avalia a utilização de dados PALSAR multitemporal, combinados com modelo digital de superfície (DSM) derivado do ALOS PRISM, para o mapeamento da cobertura da terra em uma região central do estado de São Paulo, Brasil. A área de estudo (22.5ºS 47.8 ºW) está situada na região oeste do reservatório de Barra Bonita, próximo a confluência dos rios Tietê e Piracicaba, com elevações variando entre 300 e 1000m. Os usos da terra dominante são agricultura ( cana de açúcar, cítricas e gramíneas) e florestal (eucaliptos). A vegetação natural é restrita a vegetação riparia, mata na front da cuesta e macrofitas aquáticas sazonais. Áreas urbanas presente na região são São Pedro e Aguas de São Pedro. Duas cenas PALSAR no modo Fine-Beam Single-polarization (FBS) (08 de abril de 2008 e 09 de janeiro de 2009... / Optical sensors are widely used for land cover mapping at local and small region scales, for a wide variety of applications including urban planning, forest and crop inventory, watershed management, and environmental monitoring. Land cover mapping with L-band SAR data has focused primarily on forest and wetland areas in tropical and boreal regions, with particular emphasis on monitoring tropical deforestation and regrowth. Beginning in 2006, systematic acquisitions of ALOS PALSAR have provided multi-season, near-global data sets at high (12.5 m) resolution, with the potential to substitute for or complement optical data sets for land cover mapping in regions where cloud cover is less problematic, but still limiting for seasonally varying land cover. This study evaluates the utility of multi-temporal PALSAR data, combined with a digital surface model (DSM) derived from ALOS PRISM, for land cover mapping at a site in central São Paulo state, Brazil. The study area (22.5ºS 47.8 ºW) is situated at the west end of the Barra Bonita Reservoir, at the entrance point of the Tietê River, with elevations ranging from about 300 to 1000 m. Dominant land uses are agriculture (sugar cane, citrus, pasture) and forestry (eucalyptus). Natural vegetation is largely restricted to riparian forest, forests on steep slopes, and seasonal aquatic macrophytes. Urban areas include the cities of São Pedro and Águas de São Pedro. Two PALSAR Fine-Beam Single-polarization (FBS) mode scenes (8 April 2008 and 9 January 2009... (Complete abstract click electronic access below)

Plasmonics is an important branch of nanophotonics and is the study of the interaction of electromagnetic fields with the free electrons in a metal at metallic/dielectric interfaces or in small metallic nanostructures. The electric component of an exciting electromagnetic field can induce collective electron oscillations known as surface plasmons. Such oscillations lead to the localization of the fields that can be at sub-wavelength scale and to its significant enhancement relative to the excitation fields. These two characteristics of localization and enhancement are the main components that allow for the guiding and manipulation of light beyond the diffraction limit. This thesis focuses on developing plasmonic devices for near and far-field applications. In the first part of the thesis, we demonstrate the detection of single point mutation in peptides from multicomponent mixtures for early breast cancer detection using selfsimilar chain (SCC) plasmonic devices that show high field enhancement and localization. In the second part of this work, we investigate the anomalous reflection of light for TM polarization for normal and oblique incidence in the visible regime. We propose gradient phase gap surface plasmon (GSP) metasurfaces that exhibit high conversion efficiency (up to ∼97% of total reflected light) to the anomalous reflection angle for blue, green and red wavelengths at normal and oblique incidence. In the third part of the thesis, we present a theoretical approach to narrow the plasmon linewidth and enhance the near-field intensity at a plasmonic dimer gap (hot spot) through coupling the electric localized surface plasmon (LSP) resonance of a silver hemispherical dimer with the resonant modes of a Fabry-Perot (FP) cavity. In the fourth part of this work, we demonstrate numerically bright color pixels that are highly polarized and broadly tuned using periodic arrays of metal nanosphere dimers on a glass substrate. In the fifth and final part of the thesis, we propose numerically an approach to narrow the plasmon linewidth and enhance the magnetic near field intensity at a magnetic hot spot in a hybridized metal-insulator-metal (MIM) structure. The computational method used throughout the thesis is the finite-difference time-domain method (FDTD).

Στην παρούσα διδακτορική διατριβή παρουσιάζεται η δυνατότητα ανάπτυξης νέων αισθητήρων με χρήση μιας καινοτόμας οπτικής ίνας, γνωστή ως Ίνα Φωτονικών Κρυστάλλων (ΙΦΚ) - (Photonic crystal fiber) σε συνδυασμό με νέα και λειτουργικά υλικά. Η ΙΦΚ αποτελείται από μια περιοδική συνήθως εξαγωνική δομή οπών που δρα ως τον μανδύα της ίνας και τις περισσότερες φορές κατασκευάζεται από γυαλί (SiO2) ή πολυμερές (PMMA, TOPAS, κτλ). Η αλλαγή στην διάμετρο των οπών και της απόστασης μεταξύ τους δίνει πολύ μεγάλη ευελιξία για διαχείριση των οπτικών ιδιοτήτων της. Εδώ παρουσιάζεται πώς η διήθηση νέων υλικών στις οπές της ΙΦΚ είναι μια αποδοτική μέθοδος για ενεργοποίηση της ΙΦΚ σε εξωτερικές παρεμβολές χωρίς να απαιτείται η κατασκευή μιας νέας ίνας από την αρχή. / This PhD thesis presents the possibility of development of new sensors using a novel optical fiber, called as photonic crystal fiber (PCF) in combination with new functional materials. PCF is consisted by a periodical, usually hexagonal structure of holes which acts as the cladding of the fiber and most of the times this fiber is made of glass (SiO2) or polymer (PMMA, TOPAS, etc.). The hole diameter and the pitch size of these fibers provides great flexibility for manipulation of their optical properties. Here, it is presented how the infiltration of new materials inside the holes of PCF constitutes an efficient method to sensitize the fiber to external perturbations without the need of a new fiber.

This thesis investigates techniques and designs an autonomous visual stereo based navigation sensor to improve stereo visual odometry for purpose of navigation in unknown environments. In particular, autonomous navigation in a space mission context which imposes challenging constraints on algorithm development and hardware requirements. For instance, Global Positioning System (GPS) is not available in this context. Thus, a solution for navigation cannot rely on similar external sources of information. Support to handle this problem is required with the conception of an intelligent perception-sensing device that provides precise outputs related to absolute and relative 6 degrees of freedom (DOF) positioning. This is achieved using only images from stereo calibrated cameras possibly coupled with an inertial measurement unit (IMU) while fulfilling real time processing requirements. Moreover, no prior knowledge about the environment is assumed. Robotic navigation has been the motivating research to investigate different and complementary areas such as stereovision, visual motion estimation, optimisation and data fusion. Several contributions have been made in these areas. Firstly, an efficient feature detection, stereo matching and feature tracking strategy based on Kanade-Lucas-Tomasi (KLT) feature tracker is proposed to form the base of the visual motion estimation. Secondly, in order to cope with extreme illumination changes, High dynamic range (HDR) imaging solution is investigated and a comparative assessment of feature tracking performance is conducted. Thirdly, a two views local bundle adjustment scheme based on trust region minimisation is proposed for precise visual motion estimation. Fourthly, a novel KLT feature tracker using IMU information is integrated into the visual odometry pipeline. Finally, a smart standalone stereo visual/IMU navigation sensor has been designed integrating an innovative combination of hardware as well as the novel software solutions proposed above. As a result of a balanced combination of hardware and software implementation, we achieved 5fps frame rate processing up to 750 initials features at a resolution of 1280x960. This is the highest reached resolution in real time for visual odometry applications to our knowledge. In addition visual odometry accuracy of our algorithm achieves the state of the art with less than 1% relative error in the estimated trajectories.

"N-(1-methylpyrene) monoaza-15-crown-5 (P5), N-(1-methylpyrene) monoaza-18-crown-6 (P6), N-(9-anthryl-methyl) monoaza-15-crown-5 (A5), N-(9-anthryl-methyl) monoaza-18crown-6 (A6), were synthesized and tested as fluoroionophores for potassium and sodium cations. Upon metal ion complexation, fluorescence yields increased dramatically due to an internal photoinduced electron transfer quenching mechanism (an off-on fluorescence switch). The results for these model compounds led to the design and synthesis of 1,3 alternate calixarene[4]arenecrown-5 (I) and bicyclic peptide (V). Calixarene I was synthesized and found to selectively complex potassium cations as predicted. The design of bicyclic peptide V is directed toward the selective complexation of ammonium cations. The synthesis of V involved the preparation of an open chain hexa-peptide consisting of two trityl-protected homoserine residues. Addition of an amino methyl pyrene across two homoserine residues was attempted by triflating the alcohols. The cyclization of the peptide ring is expeded to produce a basket-like structure that molecular modeling indicates should have improved selectivity over that of nonactin, the current industry standard."

Structural born vibration is the most concern issue for industry. Traditionally, the accelerometer is usually used as the major monitoring device for vibration. As the mechanism getting more and more complexity, more compact, tinier and more lighting, the traditional accelerometers are suffered from the loading effect. Its accuracy of measurement is suspected and cannot match the modern measurement requirement. Hence, the studies of fiber optic vibration sensors become an urgent issue in this era. The reflection wavelength of a fiber Bragg grating¡]FBG¡^is sensitive to the variation of the strain and temperature. Our sensor configuration is made of an interferometer and fiber Bragg grating. The vibration induces a strain of the fiber Bragg grating, and it makes a phase difference between those two light beams in the interferometer. A demodulation circuit is needed to detect the phase difference caused by the vibration. In this project, the aim is focused on the vibration measurement for some complicated rotational machines or structures. A fiber optic accelerometer will be designed and studied as a vibration monitor for the other subprojects. In this the thesis, two kinds of vibration sensor head are designed and studied, the first is a bending loss sensor head and the other is an optic fiber Bragg grating sensor head. The results are narrated as follows¡G¡]1¡^ The dynamic range of the bending loss sensing head is about 50 dB.¡]2¡^The dynamic range of the optic fiber Bragg grating sensing head is 38 dB with test frequency range between 100 ~ 400 Hz, the noise level is around 1.95 ¡Ñ 10-2 rad.

No description available.

Engineering particles at the nanoscale demands a high degree of control over process parameters during synthesis. For nanocrystal synthesis, solution-based techniques typically include application of external convective heat. This process often leads to slow heating and allows decomposition of reagents or products over time. Microwave-assisted heating provides faster, localized heating at the molecular level with near instantaneous control over reaction parameters. In this work, microwave-assisted heating has been applied for the synthesis of II-VI semiconductor nanocrystals namely, ZnO nanopods and CdX (X = Se, Te) quantum dots (QDs). Based on factors such as size, surface functionality and charge, optical properties of such nanomaterials can be tuned for application as sensors. ZnO is a direct bandgap semiconductor (3.37 eV) with a large exciton binding energy (60 meV) leading to photoluminescence (PL) at room temperature. A microwave-assisted hydrothermal approach allows the use of sub-5 nm ZnO zero-dimensional nanoparticles as seeds for generation of multi-legged quasi one-dimensional nanopods via heterogeneous nucleation. ZnO nanopods, having individual leg diameters of 13-15 nm and growing along the [0001] direction, can be synthesized in as little as 20 minutes. ZnO nanopods exhibit a broad defect-related PL spanning the visible range with a peak at ~615 nm. Optical sensing based on changes in intensity of the defect PL in response to external environment (e.g., humidity) is demonstrated in this work. Microwave-assisted synthesis was also used for organometallic synthesis of CdX(ZnS) (X = Se, Te) core(shell) QDs. Optical emission of these QDs can be altered ased on their size and can be tailored to specific wavelengths. Further, QDs were incorporated in Enhanced Green-Fluorescent Protein – Ultrabithorax (EGFP-Ubx) fusion protein for the generation of macroscale composite protein fibers via hierarchal self-assembly. Variations in EGFP- Ubx·QD composite fiber surface morphology and internal QD distribution were studied with respect to (i) time of QD addition (i.e., pre or post protein self-assembly) and (ii) QD surface charge — negatively charged QDs with dihydrolipoic acid functionalization and positively charged QDs with polyethyleneimine coating. Elucidating design motifs and understanding factors that impact the protein-nanoparticle interaction enables manipulation of the structure and mechanical properties of composite materials.

Optical biosensors are desired for the monitoring of various biochemical markers, which are relevant indicators in the treatment and diagnosis of diseases. Specifically, luminescence sensors are favorable for optical interrogation since they are highly sensitive to analyte changes and may be implemented in lifetime or intensity-based systems. In order to develop particle-based fluorescent sensors, poly(2-hydroxyethylmethacrylate) (HEMA) microspheres have been fabricated via membrane emulsification and characterized to evaluate the emulsion method and the overall process of tailoring properties to synthesize spheres of specific mean sizes. A pH-sensitive indicator seminaphthorhodafluors-4F 5-(and-6)-carboxylic acid (SNARF) was immobilized within the microspheres, and resulting sensor particles were exposed to various pH buffers to obtain a pH calibration curve based on intensity measurements. PolyHEMA microparticles were fabricated in a systematic study with measured mean sizes ranging from 8-21 um. Optical and scanning electron microscopy images revealed the formation of spherical, porous particles, which were additionally stabilized with polymer coatings. The lowest coefficient of variation value achieved was 50%, indicating the inability to produce monodisperse particles due to the dispersity of pore sizes in the membrane. SNARF was immobilized within the polyHEMA spheres, and fluorescence was observed when exposing the sensors to different pH buffers on a fluorescence microscope. Ratiometric intensity measurements for the sensor particles were obtained on a spectrofluorometer while flowing pH buffers over the immobilized spheres in a reaction chamber. The peak intensity ratio of the microparticle sensors exhibited a change in 0.9 units when decreasing the pH from 8.4 to 5.5. In the future, these pH sensing particles may be implanted alongside glucose sensing materials in order to provide valuable pH information in understanding the immune response to specific biomaterials and sensing components.

Thesis--Auburn University, 2009. / Abstract. Vita. Includes bibliographical references (p. 49).