No description available.

Among the many and varied fields of present day chemistry, that of optical activity occupies a not unimportant position. The rotatory powers of the alkali and ammonium salts of d-sec-βoctyl hydrogen phthalate have been studied in alcoholic and aqueous solution. The rotations of the salts were found to be in the order H > Li > NH4 > Na > K > Rb. It has been concluded that the variation of the molecular rotation of the salts with concentration may be explained by assuming changes in the degree of dissociation of the electrolytes and a deforming influence of the cations on the optically active anions. The effect of the addition of inorganic salts of various valence types to 0.2 M aqueous solutions of d-sec-β-octyl sodium phthalate has been investigated. The series for the depressive influence of the alkali and ammonium chlorides on the rotatory power of the optically active electrolyte is Cs+> Rb+> K+> Na+> NH4+> Li+. The corresponding series for the divalent chlorides is Ba++> Sr++> Ca++> Mg++. It is concluded that the observed effects may be attributed mainly to a deforming influence of the positive ion on the optically active negative ion, the explanation involving a consideration of the ionic radii. It is worthy of comment that the above results have been obtained by use of a carboxylic acid containing no hydroxyl group.

Detection and inspection of metal surface corrosion in the ballast tanks of U.S. Navy ships has been a long time problem. The adverse climatic conditions to which the ballast tanks are exposed and the uneven geometry of ballast tanks makes the visual inspection process of surface coatings a difficult job. Thousands of tanks are inspected yearly, with the average cost of an individual tank inspection at approximately $8-15 thousand/each. To aid the visual inspection process, this research is conducted to develop a new technique to automate the visual task of metal surface inspection by image acquisition and post processing. The best results of image processing are achieved by the enhanced contrast between the paint defect and the background using a newly developed optically active additive (OAA) used in paints. Thorough investigation of image processing algorithms has been carried out and a background of imaging theory and experiments is illustrated in this work.

The US Navy spends around $75 million on maintenance and rework of corroded structures, especially in the ballast tanks of ships. The Navy will profit immensely with better surface coating and quality at source with real time inspection system. The approach taken to improve the coating is the use of optically active paint system. This kind of paint will fluoresce with an incident UV light. The fluorescence or glow can be used to detect holidays or defects on the surface. The inspection prototype developed uses a high end camera and intense UV light source. The paint and additive properties are characterized with the help of ultraviolet-visible spectroscopy (UV Vis) to study the behavior and to help formulate a theory. The holidays or missed spots in the painted surface will appear dark and non-fluorescing which is enhanced with the use of commercial filters.

No description available.

Silicon Photonics has been a major success story in the last decade, with many photonic devices having been successfully demonstrated. The only missing component is the light source, however, as making an efficient light source in silicon is challenging due to the material's indirect bandgap. The development of a silicon light source would enable us to make an all-silicon chip, which would find many practical applications. The most notable among these applications are on-chip communications and sensing applications. In this PhD project, I have worked on enhancing silicon light emission by combining material processing and device engineering methods. Regarding materials processing, the emission level was increased by taking three routes. In all the three cases the emission was further enhanced by coupling it with a photonic crystal (PhC) cavity via Purcell effect. The three different approaches taken in this PhD project are listed below. 1. The first approach involves incorporation of optically active defects into the silicon lattice by hydrogen plasma treatment or ion implantation. This process results in broad luminescence bands centered at 1300 and 1500 nm. By coupling these emission bands with the photonic crystal cavity, I was able to demonstrate a narrowband silicon light emitting diode at room temperature. This silicon nano light emitting diode has a tunable emission line in the 1300-1600 nm range. 2. In the second approach, a narrow emission line at 1.28µm was created by carbon ion implantation, termed “G-line” emission. The possibility of enhancing the emission intensity of this line via the Purcell effect was investigated, but only with limited success. Different proposals for future work are presented in this regard. 3. The third approach is deposition of a thin film of an erbium disilicate on top of a PhC cavity. The erbium emission is enhanced by the PhC cavity. Using this method, an optically pumped light source emitting at 1.54 µm and operating at room temperature is demonstrated. A practical application of silicon light source developed in this project in gas sensing is also demonstrated. As a first step, I show refractive index sensing, which is a simple application for our source and demonstrates its capabilities, especially relating to the lack of fiber coupling schemes. I also discuss several proposals for extending applications into on-chip biological sensing.

This thesis explores the surface assembly of mechanically interlocked molecular architectures at gold surfaces for potential applications in molecular switches, anion sensing and stimuli (redox and optical) responsive molecular films. <b>Chapter One</b> introduces the field of mechanically interlocked molecules focusing on rotaxane and catenane surface assemblies in the form of single molecule thick self-assembled monolayers. A review of the surface-attached characteristics of mechanically interlocked molecules is given before exploring specific anion template directed strategies for their construction. The potential to incorporate both redox-active and optically-active functional groups within these mechanically interlocked molecules is also discussed. <b>Chapter Two</b> provides the experimental details and procedures employed in this thesis to characterise the molecular systems under investigation. <b>Chapter Three</b> introduces several surface characterisation techniques such as; ellipsometry, contact angle, X-ray reflectivity and X-ray photoelectron spectroscopy, with a particular focus of applying these tools to probe the surface co-conformation of switchable and interlocked molecules at surfaces. Electroanalytical techniques such as cyclic voltammetry, chronoamperometry and electrical impedance spectroscopy are also introduced. <b>Chapter Four</b> details the surface assembly of a series of ferrocene containing anion templated catenane self-assembled monolayers on gold. Detailed electrochemical and angle resolved X- ray photoelectron spectroscopy characterisation elucidates the co-conformation upon surface attachment. <b>Chapter Five</b> details the anion templated surface assembly of a redox-active rotaxane self- assembled monolayer on gold. Subsequent electroanalysis and X-ray photoelectron spectroscopy characterisation confirms the structural integrity of the film and a possible co- conformation at the surface is discussed. <b>Chapter Six</b> describes efforts towards constructing optically responsive hybrid d-f lanthanide containing mechanically interlocked molecules. Initial work focuses on switching characteristics of a redox switchable antennae and its ability to modulate the luminescence of a series of lanthanide complexes in solution. Subsequent surface attachment of the lanthanide complexes in the form of emissive self-assembled monolayers is also investigated.

Made available in DSpace on 2014-06-11T19:22:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-05-23Bitstream added on 2014-06-13T18:49:06Z : No. of bitstreams: 1 ennes_r_me_prud.pdf: 1370679 bytes, checksum: eb4f2a4378f82b93f832cc48f75c59ef (MD5) / Os recentes avanços na tecnologia de Sensoriamento Remoto proporcionaram o desenvolvimento de sensores orbitais com altíssima resolução espectral, capazes de fornecer medidas radiométricas em bandas estreitas e contínuas para cada pixel da imagem, definindo curvas espectrais com potencial de discriminar diferentes componentes da matéria. Diante disso, o objetivo geral deste trabalho foi de avaliar a contribuição de imagens hiperespectrais na identificação de componentes opticamente ativos presentes em um corpo d’água, considerado de boa qualidade. Para tanto, uma imagem hiperespectral Hyperion foi adquirida simultaneamente com variáveis limnológicas coletadas em alguns pontos georreferenciados no reservatório de Itupararanga. Após a correção atmosférica da imagem, extraíram curvas espectrais nos locais geográficos dos pontos, nos quais se aplicaram técnicas de análise de espectros, tais como, remoção do contínuo, razão de bandas e análise derivativa. Os dados hiperespectrais originais e os resultantes da aplicação de técnicas foram correlacionados com algumas variáveis limnológicas... / The recent improvements in the technology of Remote Sensing are providing the development of sensors with high spectral resolution that can supply radiometric measurements in narrow and continuous bands for each pixel of the image, defining spectral curves with potential of separating several components of the matter. Due to that, the general objective of this work was evaluating the contribution of hyperspectral images in the identification of optically active constituents present in a body of water, considered good quality. To reach the proposed objective, a hyperspectral imagery of EO-1/Hyperion orbital sensor was acquired simultaneously with limnological variables collected in some points in the body of water. After correcting the atmospheric effects, in the geographical locations of those points, spectral curves of the hyperspectral image were extracted, in which techniques of spectral analysis were applied, such as, continuum removal, derivative analysis and ratio analysis. The hyperspectral original data and the resultants of the application of techniques were correlated with some limnological variables. Of the applied techniques, the derivative analysis provided better differentiation among the optically active constituents... (Complete abstract, click electronic access below)

Made available in DSpace on 2014-06-11T19:30:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-11-28Bitstream added on 2014-06-13T19:00:45Z : No. of bitstreams: 1 pereira_acf_dr_prud.pdf: 5065860 bytes, checksum: cf34424bad6a80c07230f80a12e3567a (MD5) / Na sociedade atual, discussões relacionadas à água potável tem ocupado um espaço importante, principalmente no meio científico, onde, através de pesquisas voltadas à disponibilidade e qualidade das águas é possível preparar diagnósticos e apontar soluções para planejadores e tomadores de decisões. Nesse contexto, o objetivo geral do trabalho foi desenvolver um método para inferência de variáveis limnológicas que indicam a qualidade da água e estejam associadas à sua característica espectral, em um reservatório de uso múltiplo e avaliar sua correlação com dados espectrais tomados “in situ” e extraídos de imagens orbitais de satélites de alta resolução espacial. Para tanto, uma imagem multiespectral do satélite Ikonos II foi adquirida, quase simultaneamente a coleta de dados limnológicos e espectrais “in situ”, em pontos amostrados adequadamente no corpo d’água, e posicionados com GPS. Devido à heterogeneidade das condições do tempo no levantamento de campo, uma nova abordagem amostral foi necessária, que se deu pela divisão da amostra em quatro conjuntos, quais foram: conjunto 1 (céu aberto e vento fraco), conjunto 2 (céu aberto e vento de médio a forte), conjunto 3 (céu nublado e vento fraco) e conjunto 4 (céu nublado e vento de médio a forte)... / In current society, drinkable water has been the subject of innumerable debates, mainly in scientific groups, in which, through researches focused on the availability and water quality, it is possible to prepare diagnoses and point out solutions to planners and decision makers. In this context, the general aim of the research was to develop a method for the inference of physical limnological variables that indicate the quality of the water and that are associated to its spectral characteristic, in a multiple use reservoir and evaluate its correlation to spectral data collected in situ and extracted from orbital images of high definition space sattelites. In order to achieve that, a multispectral image of the satellite Ikonos II was acquired, almost simultaneously to the gathering of limnological and spectral data “in situ”, in points sampled adequately in the water surveyed, and positioned by means of GPS. Due to the heterogeneous weather conditions when taking the ground samples, a new sampling approach was necessary, and it occurred with the division of the sample in four settings, which were: setting 1 (clear sky and mildly windy), setting 2 (clear sky and windy), setting 3 (overcast sky and mildly windy) and setting 4 (overcast sky and windy)... (Complete abstract click electronic access below)

Resumo: Na sociedade atual, discussões relacionadas à água potável tem ocupado um espaço importante, principalmente no meio científico, onde, através de pesquisas voltadas à disponibilidade e qualidade das águas é possível preparar diagnósticos e apontar soluções para planejadores e tomadores de decisões. Nesse contexto, o objetivo geral do trabalho foi desenvolver um método para inferência de variáveis limnológicas que indicam a qualidade da água e estejam associadas à sua característica espectral, em um reservatório de uso múltiplo e avaliar sua correlação com dados espectrais tomados "in situ" e extraídos de imagens orbitais de satélites de alta resolução espacial. Para tanto, uma imagem multiespectral do satélite Ikonos II foi adquirida, quase simultaneamente a coleta de dados limnológicos e espectrais "in situ", em pontos amostrados adequadamente no corpo d'água, e posicionados com GPS. Devido à heterogeneidade das condições do tempo no levantamento de campo, uma nova abordagem amostral foi necessária, que se deu pela divisão da amostra em quatro conjuntos, quais foram: conjunto 1 (céu aberto e vento fraco), conjunto 2 (céu aberto e vento de médio a forte), conjunto 3 (céu nublado e vento fraco) e conjunto 4 (céu nublado e vento de médio a forte)... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In current society, drinkable water has been the subject of innumerable debates, mainly in scientific groups, in which, through researches focused on the availability and water quality, it is possible to prepare diagnoses and point out solutions to planners and decision makers. In this context, the general aim of the research was to develop a method for the inference of physical limnological variables that indicate the quality of the water and that are associated to its spectral characteristic, in a multiple use reservoir and evaluate its correlation to spectral data collected "in situ" and extracted from orbital images of high definition space sattelites. In order to achieve that, a multispectral image of the satellite Ikonos II was acquired, almost simultaneously to the gathering of limnological and spectral data "in situ", in points sampled adequately in the water surveyed, and positioned by means of GPS. Due to the heterogeneous weather conditions when taking the ground samples, a new sampling approach was necessary, and it occurred with the division of the sample in four settings, which were: setting 1 (clear sky and mildly windy), setting 2 (clear sky and windy), setting 3 (overcast sky and mildly windy) and setting 4 (overcast sky and windy)... (Complete abstract click electronic access below) / Orientador: Maria de Lourdes Bueno Trindade Galo / Coorientador: Edivaldo Domingues Velin / Banca: Cláudio Clemente Faria Barbosa / Banca: Waterloo Pereira Filho / Banca: Renata Ribeiro de Araújo / Banca: Vilma Mayumi Tachibana / Doutor