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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
381

Estudo espectroscópico e eletroquímico da redução de íons perclorato sobre superfícies eletromodificadas de estanho / Study of spectroscopic and electrochemical reduction perchlorate ions on tin surfaces electromodified

Sousa, Edson Barbosa de 23 November 2005 (has links)
Medidas eletroquímicas, incluindo cronoamperometria, voltametria cíclica, procedimentos eletroquímicos de envelhecimento de filmes superficiais, espectroscopia de absorção no infravermelho, espectroscopia Raman in situ e ex situ, incluindo o efeito SERS, foram empregados no estudo da redução eletroquímica de íons perclorato a cloreto sobre eletrodo de estanho. Solução de perclorato de sódio 0,5 mol L-1 foi utilizada como eletrólito. Observou-se que a concentração máxima de cloreto produzida em decorrência da redução de íons perclorato (5,0 x 10-5 mol L-1) ocorre na região de potenciais localizada no final da contribuição de corrente da dupla camada elétrica e início da região de desprendimento de hidrogênio. A concentração limite de cloreto é decorrente do estabelecimento de um equilíbrio entre os íons cloreto na solução e cloreto adsorvido que inativa os sítios na superfície, impedindo a continuidade do processo. Programas de perturbação de potencial visando a eletromodificação da superfície do estanho foram aplicados, com o objetivo de verificar a ocorrência de mudanças das propriedades eletrocatalíticas dessas superfícies. A influência das variáveis, velocidade da perturbação, tempo de duração e limites de potencial na cinética de redução de perclorato e na concentração máxima de cloreto foi estudada. Em todos os casos a concentração máxima de cloreto detectada na solução foi de 2,0 x 10-5 mol L-1, exceto no tratamento de ativação eletroquímica quando essa concentração atinge 5,0 x 10-5 mol L-1. A influência da presença de óxidos superficiais, temperatura e agitação da solução, pH, e tempo de polarização no processo de redução de perclorato também foi avaliada. Concluiu-se que (i) a presença de óxidos catalisa o processo de redução; (ii) a influência da temperatura é significativa a 70 °C; (iii) a agitação e o pH da solução não exercem influência na concentração máxima de cloreto produzida e (iv) a concentração máxima de cloreto estabiliza-se após cerca de 150 minutos de polarização. / Electrochemical measurements including chronoamperometry, cyclic voltammetry, film surface electrochemical ageing procedures, FTIR and Raman spectroscopy including the SERS effect were carried out in order to study the electrochemical reduction of perchlorate ions at tin electrodes. Sodium perchlorate solution 0.5 mol L-1 was employed as electrolyte. It was observed that maximum chloride concentration produced by the perchlorate reduction (5.0 x 10-5 mol L-1), takes place within a potential range comprising the negative side of de double layer region and the positive side of the hydrogen evolution region. The upper limit of chloride concentration occurs due to the establishment of an equilibrium between the chloride ions in solution and the adsorbed chloride ions that blocks the surface sites where the reduction process takes place. In order to electromodify the tin surface, the electrode was subjected to perturbing potential programs, aiming to evaluate changes in the electrocatalytic properties of the modified sufaces. The influence of the experimental variables perturbation sweep rate as well as perturbation time and potential limits on the perchrolate reduction kinetic and on the maximum chloride concentration was studied. Except to the activation treatment, the maximum chloride concentration was 2.0 x 10-5 mol L-1 for all the applied perturbation programs. The influence of the oxides on the electrode surface, stirring, temperature, pH and polarization time on the reduction process was evaluated too. It was shown that (i) the presence of oxides on the electrode surface favors the reduction reaction; (ii) there is significant influence of temperature at 70 °C; (iii) pH and stirring the solution exerts no influence on the maximum chloride concentration produced and (iv) the maximum chloride concentration produced by electroreduction is reached after 150 minutes.
382

Método prático para a medição e comparação da emissividade de raios infravermelhos em diferentes tecidos contendo biocerâmica / Practical method for Infrared rays emissivity measurement and comparison in different fabrics containing bioceramics

Affonso, Renan Guazzelli 28 June 2016 (has links)
Por décadas a radiação infravermelha tem sido usada de forma estética e terapêutica, e é caracterizada por ter a propriedade de penetrar na pele. O surgimento de novas tecnologias permitiu a criação de têxteis funcionais, entre eles os tecidos contendo biocerâmica, que absorvem o calor do corpo, ativando a biocerâmica presente e emitindo raios infravermelhos longos, que penetram na pele ativando a microcirculação sanguínea. Porém, tecidos desse tipo só tiveram eficiência comprovada por testes clínicos, que são métodos caros e demorados, ou por analogia baseada no tipo de construção. O objetivo deste estudo foi elaborar um método prático para medir a emissividade de tecidos contendo biocerâmica, utilizando um espectrofotômetro de raios infravermelhos, comparar a emissividade desses tecidos, além de realizar uma análise de fluorescência de raios X a fim de descobrir os elementos químicos presentes nos tecidos, para confirmar quaisquer diferenças de emissividade entre os mesmos. Concluiu-se que é possível medir a emissividade de tecidos contendo biocerâmica através do aquecimento das amostras, simulando a ação do tecido junto ao corpo, e posteriormente realizando ensaios em um espectrofotômetro de infravermelhos por transformada de Fourier, onde picos de emissão foram encontrados em cada tecido analisado, o que possibilitou o cálculo da emissividade (expressa em contagens de área) através do ajuste de uma curva gaussiana em cada pico de emissão. Através da fluorescência de raios X foram encontrados diferentes elementos químicos na composição das amostras, podem ser a causa da diferença de emissividade entre os tecidos / The infrared radiation has been used on aesthetic and therapeutic way for decades, and is characterized for being able to penetrate deeply underneath the skin. New technologies appeared, enabling the development of functional textiles, among them textiles containing bioceramics that absorb the body heat, activating the bioceramic on it and emitting far infrared rays, which penetrate into the skin, activating the blood microcirculation. However, the efficiency of this sort of fabrics was proven only by clinical tests, which are very expensive and time consuming, and by construction analogy. The main objective of this study was to develop a practical method for measuring fabrics containing bioceramics emissivity, using an infrared spectrophotometer, comparing the fabrics emissivity, besides doing an X ray fluorescence analysis in order to discover the chemical elements that composes the fabrics, to confirm any emissivity differences between them. It was concluded that it is possible to measure the emissivity of fabrics containing bioceramics by heating the samples, simulating the action of the fabric on the body, and subsequently performing tests on a Fourier transform infrared spectrophotometer, where emission peaks were found on the fabrics, that enabled the emissivity calculation (expressed in area counts) by adjusting a Gaussian curve at each emission peak. By the X ray fluorescence different chemical elements were found on the fabrics composition, which can be the reason for the emissivity difference between them
383

Enabling awareness in nursing homes with mobile health technologies

Klakegg, S. (Simon) 22 February 2019 (has links)
Abstract This thesis explores the use of assistive in-situ technologies for formal caregivers in nursing homes. More specifically, focus is placed on improving context awareness and medication management. Although these topics have previously been researched for elderly care in general, few solutions targeting nursing homes have been generated. As the aging population further increases the burden on this care environment, it is important that solutions are found to help maintain care quality. The main findings in this thesis emphasise how technology can assist formal caregivers and facilitate increased patient wellbeing. The articles presented in this thesis describe our creation of a context-aware sensor system (named CARE) and a non-expert miniaturised near-infrared spectroscopy (MNIRS) solution. Both systems were designed iteratively with the help of nurses and were evaluated in a nursing home. CARE quantifies elderly residents’ behaviour, analyses the resulting data and produces valuable and actionable insights for nurses. Results from a two-month-long user study demonstrate that the system can facilitate increased awareness of patients’ needs and enhance care service. The custom MNIRS solution allows nurses to scan pharmaceuticals and obtain accurate identifications. This method significantly outperforms currently available tools in nursing homes and represents a promising solution that can reduce medication mismanagement. In the discussion section of the thesis, we revisit the research questions defined in the introduction and examine how each were answered. In addition, we discuss the augmentation of nursing home technology and various stakeholders’ perspectives. We then highlight how the work covered in this thesis was conducted in collaboration with industry and offer some conclusions, limitations and reflections. / Tiivistelmä Tämä väitöstyö tutkii paikkasidonnaisten teknologioiden käyttöä hoitajien työn helpottamiseksi vanhusten palvelukodeissa. Työn keskiössä on erityisesti kontekstitietoisuuden lisääminen ja lääkehoidon valvonta. Näitä aiheita on tutkittu laajalti aiemminkin, mutta aitoihin ympäristöihin keskittyviä ratkaisuja on vielä vain vähän. Väestön ikääntyminen aiheuttaa haasteita vanhustenhoidossa, ja siksi on tärkeää kehittää ratkaisuja hoidon laadun ylläpitoa varten. Väitöstyön löydökset painottavat teknologian roolia hoitajien avustajana sekä hoidettavien hyvinvoinnin ylläpitäjänä. Työn artikkelit kuvailevat kontekstitietoisen järjestelmän (CARE) koko kehitys- ja elinkaaren sekä lähi-infrapunaspektroskopiaan perustuvan ratkaisun lääkehoidon prosessien parantamiseksi. Molemmat järjestelmät kehitettiin iteratiivisesti hoitajien avulla ja koestettiin aidossa ympäristössä vanhainkodissa. CARE analysoi asiakkaiden liikkeitä ja toimintoja sekä visualisoi niistä korkeamman tason tietoa hoitajille. Kahden kuukauden kenttäkokeen tuloksena voidaan todeta, että järjestelmät yhdessä voivat auttaa hoitajia ymmärtämään asiakkaiden tarpeita sekä parantamaan hoidon laatua. Lähi-infrapunaspektroskopiaan perustuvalla kannettavalla ratkaisulla puolestaan hoitajat voivat varmistaa lääkehoidon oikeellisuuden. Tämä menetelmä on tarkempi ja parempi kuin tämänhetkiset käytössä olevat ratkaisut lääkkeiden oikeaksi toteamiseen. Väitöstyön keskusteluosuus palaa tutkimuskysymyksiin ja selventää, kuinka tehty työ ja saavutetut tulokset vastaavat niihin. Lisäksi keskustelu antaa yleiskuvan eri osapuolien näkemyksistä kehitetyn ratkaisun hyödyistä ja sen soveltuvuudesta käytännön työhön. Lopuksi väitöstyö luo katsauksen yhteistyön rooliin eri osa-alueiden toteuttamisessa ja esittää kriittisen näkökulman työn puutteisiin sekä yhteenvedon.
384

Near-Infrared Spectroscopy neurofeedback (NIRS neurofeedback) em crianças com Transtorno de Déficit de Atenção/Hiperatividade (TDAH)

Londero, Igor January 2015 (has links)
As intervenções com neurofeedback têm tido grande difusão na área como uma alternativa possível para tratamento do Transtorno de Déficit de Atenção/Hiperatividade (TDAH). Este estudo tem o objetivo de avaliar a viabilidade da utilização de um sistema de neurofeedback de baixo custo chamado Near Infrared Spectroscopy/Hemoencephalography Neurofeedback (NIR/HEG-NF) para tratar crianças com TDAH. Método: trata-se de um estudo clínico piloto aberto, que incluiu 5 crianças (3 meninos e 2 meninas - idade 10,4 ± 0,89 anos) com TDAH-C (tipo combinado). Os indivíduos completaram um programa de 24 sessões de NIR/HEG-NF, duas ou três vezes por semana. Os seguintes desfechos foram avaliados pré e pós-tratamento: 1) sintomas de desatenção e hiperatividade; 2) desempenho neuropsicológico; 3) imagens de SPECT cerebral; 4) qualidade de vida; e 5) efeitos adversos. Resultados: houve maior resistência do que o esperado para a participação dos indivíduos devido a vários fatores, tais como logísticos para a participação nas sessões e requerimento de não uso de medicação durante o protocolo. Detectamos uma diferença significativa na comparação pré e pós-intervenção nos escores atribuídos pelos pais na dimensão de hiperatividade e impulsividade do Swanson, Nolan and Pelham Questionnaire (SNAP-IV) (p = .042; tamanho de efeito [ES] =.38) e uma tendência de melhora nos escores atribuídos pelos pais e professores na dimensão desatenção (p = .066; ES = .47 / p = .068; ES = .60) naquelas crianças que finalizaram o tratamento. Detectamos uma tendência de aumento perfusional em diferentes partes do córtex cerebral em três indivíduos. As comparações pré e pós-intervenção nas outras medidas não indicaram diferenças estatisticamente significativas. Não foram relatados efeitos adversos significativos. Discussão: Os achados iniciais sugerem que o NIR/HEG-NF como tratamento para sintomas de TDAH pode ser promissor e deve ser melhor investigado. O protocolo lança luz sobre novas abordagens para avaliar a eficácia da intervenção. Pode-se, por exemplo, implementar o programa de intervenção no ambiente escolar e com uso concomitante de medicamentos para superar as resistências na alocação de pacientes e para uma avaliação com maior validade externa. / Background and objectives: Neurofeedback interventions have been quick and extensively introduced for clinicians to treat Attention-Deficit/Hyperactivity Disorder (ADHD). This study aims to assess the feasibility of using a low cost neurofeedback system called Near Infrared Spectroscopy/ Hemoencephalography Neurofeedback (NIR/HEG-NF) for treating children with ADHD. Method: This open pilot clinical study included 5 children (3 boys and 2 girls - age 10.4 ± 0.89 years) with ADHD-C (combined type). The subjects completed a program of 24 sessions of NIR/HEG-NF, two or three times a week. The following outcomes were assessed pre and post-treatment: 1) clinical symptoms of inattention and hyperactivity; 2) neuropsychological performance; 3) brain SPECT images; 4) quality of life and; 5) adverse effects. Results: Higher resistance than expected was experienced for patient allocation due to logistic reasons to attend the sessions in the hospital and the requirement of not using medication during the protocol. We detected a significant decrease in hyperactivity/impulsivity comparing pre and post-intervention scores in the parent’s Swanson, Nolan and Pelham Questionnaire - SNAP-IV (p = .042; Effect Size [ES] r = .38) and a trend of improvement in scores attributed by parents and teachers in inattention (p = .066; r = .47 / p = .068; r = .68) . We detected a trend for increased perfusion in different parts of the entire cortex in 3 subjects. Comparisons between pre and post-intervention scores in other measures did not suggest meaningful differences. No significant adverse effects were reported. Discussion: Our initial findings suggest that NIR/HEG-NF technique might be promising and should be further investigated. The protocol shed light on new approaches to assess the effectiveness of the intervention such as the need to both implement the intervention program in a school environment and to pursue the investigation of the treatment effects with concomitant use of medications to surpass resistances to enroll patients and to have an assessment with more external validity.
385

Process Analytical Technology : suivi en temps réel d’une opération d’enrobage et de curing et nouvelles avancées dans la caractérisation du film polymère / Process Analytical Technology : real-time monitoring of coating and curing operation and new insight into polymer film characterisation

Gendre, Claire 12 December 2011 (has links)
La mise en place de la démarche PAT (Process Analytical Technology), initiée par la FDA (Food and Drug Administration) s’est développée au cours de ces dernières années, au sein de l’industrie pharmaceutique. Grâce à des contrôles en continu au coeur des procédés de fabrication, elle permet une meilleure compréhension et une maîtrise de la formulation et du procédé, afin d’assurer la qualité finale des médicaments.A travers ce travail, nous avons mis en place un suivi en temps réel, par spectroscopie proche infrarouge, d’une opération d’enrobage suite à l’intégration d’une sonde à l’intérieur d’une turbine d’enrobage. La quantité d’enrobage, déterminée par une simple et rapide pesée mais néanmoins soumise à la variabilité de la masse des comprimés nus, ainsi que l’épaisseur du film, obtenue avec précision par imagerie térahertz ont servi de valeurs de référence pour calibrer l’information spectrale. Dans les deux cas, ces deux attributs qualité critiques ont été prédits avec de faibles erreurs de prédiction, qui se sont révélées être similaires. Par ailleurs, la prédiction en temps réel des propriétés de dissolution de comprimés prêts à être libérés, à partir de spectres acquis in-line, a permis de déterminer l’arrêt optimal de l’opération d’enrobage.Suite à un enrobage réalisé à partir d’une dispersion aqueuse de polymère une étape supplémentaire de traitement thermique ou curing est généralement nécessaire afin de stabiliser le film d’enrobage. Un travail de caractérisation mené à partir de techniques innovantes a permis d’apporter un nouvel éclairage sur la compréhension des phénomènes impliqués dans la formation du film au cours du curing. La caractérisation approfondie de la structure d’enrobage de comprimés soumis à un curing en turbine (conditions dynamiques) a mis en évidence la diminution de la porosité, couplée à l’évaporation de l’eau et à une meilleure organisation des chaînes de polymère au cours du curing. L’étude de comprimés soumis à un curing de référence en étuve durant 24 h (conditions statiques) a confirmé l’obtention d’un film stable après 4 h de curing dynamique. De nouveaux phénomènes, indépendants du curing, liés à la cristallisation et à la migration de l’alcool cétylique, couplée à la migration du lauryl sulfate de sodium, au sein de la couche d’enrobage ont été détectés au cours de la conservation des comprimés enrobés. / Implementation of PAT (Process Analytical Technology) approach has recently been promoted by the FDA (Food and Drug Administration) within the pharmaceutical industry. A desired goal of the PAT framework is to enhance understanding and control of the manufacturing process through timely measurements, during processing, to ensure final product quality. Real-time monitoring of a coating operation was performed from in-line Near Infrared (NIR) measurements inside a pan coater. Mass of coating materials, determined by simple and fast weighing but depending on core tablet weight uniformity, and film coating thickness, obtained from accurate and non-destructive Terahertz Pulsed Imaging (TPI) measurements, were used as reference values to calibrate NIR spectral information. In both cases, these two critical quality attributes were predicted with low predictive errors, which were found to be similar. In addition, real-time predictions of drug release from cured tablets were carried out by in-line NIR measurements. The coating operation was successfully stopped when desired dissolution criteria were achieved. A post-coating thermal treatment, known as curing, is generally required to stabilize film coating from aqueous polymer dispersion. Innovative techniques were jointly used to elucidate the underlying mechanisms of film formation along the curing process. This study provided a new insight into the tablet coating structure, highlighting a reduced internal coating porosity, a decrease in water content and showing a better structural rearrangement of polymer chains, with dynamic curing. All investigated techniques confirmed that a stabilized state was reached after a 4 h dynamic curing in comparison with a reference curing carried out in an oven for 24 h. Interestingly even prior to curing, new findings were pointed out, during coated tablets storage, related to the crystallisation and the upward migration of cetyl alcohol, coupled to the downward migration of sodium lauryl sulfate within the coating layer.
386

Avaliação da qualidade do lenho de árvores de Eucalytpus geneticamente modificadas / Evaluation of wood quality of genetically modified Eucalyptus trees

Vire, Nayara Marcon 29 July 2016 (has links)
Este estudo tem como objetivo analisar a qualidade do lenho das árvores de eucalipto geneticamente modificadas e seus respectivos controles (clones convencionais). Foram selecionadas 70 árvores de eucalipto, ao 12º mês de 14 tratamentos (10 eventos modificados e 4 clones convencionais) representando 5 árvores/tratamento. As amostras do lenho foram coletadas do tronco das árvores com sonda de Pressler para análise das suas características anatômicas, densidade aparente do lenho (microdensitometria dos raios X) e propriedades químicas (espectroscopia no infravermelho próximo). As propriedades anatômicas e a densidade aparente do lenho indicaram poucas diferenças significativas entre as árvores dos tratamentos. Nas análises da espectroscopia no infravermelho próximo (NIR) foram encontrados modelos satisfatórios para a densidade aparente do lenho, a fração parede e para o teor de celulose. O lenho das árvores dos eventos modificados e dos clones convencionais mostrou pequenas diferenças nas características anatômicas e físicas, sendo caracterizado como lenho juvenil; assim as árvores devem ser analisadas em idades mais avançadas, com lenho de transição e adulto. Os resultados constituem-se parte da análise das árvores de eucalipto geneticamente modificadas, subsidiando os estudos genéticos visando obter altos níveis de produtividade. / This study aims to analyze the quality of the wood of genetically modified eucalyptus trees and their respective controls (conventional clones). 70 eucalyptus trees were selected at 12 months of 14 treatments (10 modified events and 4 conventional clones) representing 5 trees / treatment. The wood samples were collected of the trunk of the eucalyptus trees with Pressler increment borer for the analysis of their anatomical features, density of wood (microdensitometry of X-rays) and chemical properties (near infrared spectroscopy). The anatomical properties and wood density of eucalypts trees showed few significant differences between treatments. In the analysis of near infrared spectroscopy (NIR) have been found satisfactory models for the apparent density of the wood, the wall portion and the cellulose content. The wood from the trees of the modified events and conventional clones showed small differences in the anatomical and physical characteristics, being characterized as juvenile wood; so the trees must be analyzed at older ages, with wood transition and adult. The results are a part of the analysis of genetically modified eucalyptus trees, supporting genetic studies to obtain high levels of productivity.
387

Optical and lasing properties of near IR dye-doped sol-gel glass thin films. / 摻近紅外染料溶凝膠薄膜之光學及激光性質研究 / Optical and lasing properties of near IR dye-doped sol-gel glass thin films. / Shan jin hong wai ran liao rong ning jiao bo mo zhi guang xue ji ji guang xing zhi yan jiu

January 2005 (has links)
Chan Jacklynn = 摻近紅外染料溶凝膠薄膜之光學及激光性質研究 / 陳在琳. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 137-152). / Text in English; abstracts in English and Chinese. / Chan Jacklynn = Shan jin hong wai ran liao rong ning jiao bo mo zhi guang xue ji ji guang xing zhi yan jiu / Chen Zailin. / Abstract --- p.i / Acknowledgements --- p.v / Publications --- p.vii / Table of Contents --- p.viii / List of Figures --- p.xi / List of Tables --- p.xiv / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Sol-gel Glass Waveguides --- p.3 / Chapter 1.2 --- Ellipsometry --- p.7 / Chapter 1.3 --- Aim of this Research Work and Organization of Thesis --- p.12 / Chapter 2 --- Basics on Ellipsometry --- p.16 / Chapter 2.1 --- Principle of Ellipsometry --- p.17 / Chapter 2.1.1 --- Definition of Ellipsometric Parameters --- p.17 / Chapter 2.1.2 --- Configurations of an Ellipsometer --- p.22 / Chapter 2.2 --- Mathematical Representation of Ellipsometry --- p.26 / Chapter 2.2.1 --- Bulk Material Structure --- p.26 / Chapter 2.2.2 --- Single Layer Structure --- p.28 / Chapter 2.3 --- Parameterization of Optical Functions --- p.31 / Chapter 2.3.1 --- Optical Functions --- p.34 / Chapter 2.3.2 --- Regression Analysis --- p.38 / Chapter 3 --- Modification of Rotating-Polarizer-Analyzer Ellipsometer --- p.40 / Chapter 3.1 --- Principle of RPA System --- p.41 / Chapter 3.2 --- Optical Setup of RPA System --- p.45 / Chapter 3.3 --- Components of the System and Modification for Infrared Measurement --- p.47 / Chapter 3.3.1 --- Light Source --- p.47 / Chapter 3.3.2 --- Monochromator --- p.52 / Chapter 3.3.3 --- Polarizers and Analyzer --- p.53 / Chapter 3.3.4 --- Detector and Data Reduction --- p.54 / Chapter 3.4 --- Optical Alignment --- p.59 / Chapter 3.5 --- Alignment of the Azimuthal Angles of the Polarizers --- p.61 / Chapter 3.6 --- Calibration Procedure --- p.63 / Chapter 3.6.1 --- Calibration by Gold Film on Silicon --- p.63 / Chapter 3.6.2 --- Calibration by Silicon Dioxide Film on Silicon --- p.67 / Chapter 4 --- Near Infrared Dyes in Sol-gel Waveguides --- p.72 / Chapter 4.1 --- Sol-gel Process --- p.73 / Chapter 4.2 --- Near Infrared Dyes in Sol-gel Waveguides --- p.77 / Chapter 4.2.1 --- Development of Near Infrared Dyes --- p.77 / Chapter 4.2.2 --- Studies on Near Infrared Dye Solid State Laser --- p.79 / Chapter 5 --- Optical Properties of Dye-doped Sol-gel Waveguides --- p.83 / Chapter 5.1 --- Experimental Procedure --- p.84 / Chapter 5.1.1 --- Preparation of Samples --- p.84 / Chapter 5.1.1.1 --- Materials --- p.84 / Chapter 5.1.1.2 --- Procedure --- p.86 / Chapter 5.1.2 --- Discussion on Synthesis of Infrared Dye-doped Sol-gel Waveguides --- p.88 / Chapter 5.1.2.1 --- Choice of Solvents --- p.89 / Chapter 5.1.2.2 --- Thermal Treatment and Lifetime --- p.93 / Chapter 5.1.2.3 --- Necessity of Addition of GLYMO --- p.94 / Chapter 5.1.3 --- Sample Characterization --- p.96 / Chapter 5.2 --- Surface Morphology --- p.97 / Chapter 5.3 --- Optical Properties of Dye-doped Zirconia Organically Modified Silicate Waveguides --- p.100 / Chapter 5.3.1 --- Modeling of Ellipsometric Values --- p.101 / Chapter 5.3.2 --- Interpretation of the Modeling Results --- p.107 / Chapter 6 --- Amplified Spontaneous Emission Based on Sol-gel Waveguides --- p.109 / Chapter 6.1 --- Experimental Setup --- p.110 / Chapter 6.2 --- Features of ASE and Fluorescence --- p.112 / Chapter 6.3 --- Prolonged Thermal Treatment Effect on Light Emission --- p.119 / Chapter 6.3.1 --- Difference in Preparation of Samples --- p.121 / Chapter 6.3.2 --- Light Emission of Samples under Extended Thermal Treatment --- p.123 / Chapter 6.3.3 --- Directionality of the Emission --- p.125 / Chapter 6.3.4 --- Some Features of the Emission --- p.127 / Chapter 7 --- Conclusion and Recommendation --- p.133 / Chapter 7.1 --- Conclusion --- p.133 / Chapter 7.2 --- Recommendation --- p.135 / Bibliography --- p.137
388

Particle size analysis, quantification and identification of microplastics in selected consumer products : a critical comparison of methods and analytical techniques

Renner, Kofi Omare January 2018 (has links)
Microplastics are particles that are < 5 mm in size and come from a wide range of sources. The global distribution in terrestrial and aquatic environments indicates they are likely to cause harm to living organisms. They are used in a variety of personal care products and kitchen scourers. To advance further studies, different approaches have been developed in recent years. In this research, a comparison of methods and analytical techniques were applied to characterise microplastics in two toothpastes and two facial scrubs. The analysis of microplastics was determined using light microscopy, laser diffraction, Fourier-transform infrared spectroscopy. This research reports for the first time, the application of Imaging flow cytometry to characterise microplastics, and was explored to characterise smaller sized particles in each product. The methods developed where validated by characterising particles abraded from kitchen scourers. Two market leading and three chain store brands of kitchen scourers were utilised for the characterisation of microplastics. The application of the different techniques indicated differences in the size, number and morphological characteristics of the particles analysed. The different approaches developed for particle extraction, and the analytical techniques had an apparent influence on the results produced. Currently, there are no universally accepted laboratory protocol and analytical techniques to characterise microplastics. However, this research can serve as a reference point to promote more studies on laboratory methods and analytical techniques to characterise microplastics, with the hope of understanding better these complex particles.
389

Development of Portable Diffuse Optical Spectroscopic Systems For Treatment Monitoring

Fong, Christopher January 2017 (has links)
The goal of this dissertation is to demonstrate the utility of portable, small-scale diffuse optical spectroscopic (DOS) systems for the diagnosis and treatment monitoring of various diseases. These systems employ near-infrared light (wavelength range of 650nm to 950nm) to probe human tissue and are sensitive to changes in scattering and absorption properties of tissues. The absorption is mainly influenced by the components of blood, namely oxy- and deoxy-hemoglobin (HbO2 and Hb) and parameters that can be derived from them (e.g. total hemoglobin concentration [THb] and oxygen saturation, StO2). Therefore, I focused on diseases in which these parameters change, which includes vascular diseases such as Peripheral Atrial Disease (PAD) and Infantile Hemangiomas (IH) as well as musculoskeletal autoimmune diseases such as Rheumatoid Arthritis (RA). In each of these specific diseases, current monitoring techniques are limited by their sensitivity to disease progression or simply do not exist as a quantitative metric. As part of this project, I first designed and built a wireless handheld DOS device (WHDD) that can perform DOS measurements at various tissue depths. This device was used in a 15-patient pilot study for infantile hemangiomas (IH) to differentiate diseased skin from normal skin and monitor the vascular changes during intervention. In another study, I compare the ultra-small form- factor WHDD’s ability to monitor synovitis and disease progression during a patient’s treatment of RA against the capabilities of a proven frequency domain optical tomographic (FDOT) system that has shown to differentiate patients with and without RA. Learning from clinical utility of the WHDD from these two studies, I adapted the WHDD technology to develop a compact multi- channel DOS measurement system to monitor perfusion changes in the lower extremities before and after surgical intervention for patients with peripheral artery disease (PAD). Using this multi- channel system, which we called the vascular optical spectroscopic measurement (VOSM) system, our group conducted a 20-subject pilot study to quantify its ability to monitor blood perfusion before and after revascularization of stenotic arteries in the lower extremities. This proof-of- concept study demonstrated how DOS may help vascular surgeons perform revascularization procedures in the operating room and assists in post-operative treatment monitoring of vascular diseases.
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Avaliação da influência do material de confecção das matrizes no teste de conversão monomérica por espectrometria no infravermelho de um compósito / Evaluation of the influence of the mould material on the degree of conversion by infrared spectroscopy of a composite

Adriana Riedlinger Mont'Alverne Bordalo 18 December 2007 (has links)
Este estudo teve por objetivo avaliar, in vitro, a influência do material de confecção das matrizes, traçando um perfil da conversão monomérica de um compósito micro-híbrido, além de avaliar qual dos materiais testados mais se assemelha a uma matriz de dentina. A avaliação foi feita através da análise do grau de conversão (GC). Foram confeccionadas 3 matrizes bipartidas, sendo estas de teflon negro, tefon branco e aço inoxidável, ambas com 10mm de diâmetro e 2 mm de profundidade. Para o grupo controle foi utilizado um incisivo central bovino, o qual teve sua face vestibular aplainada em uma lixadeira sob refrigeração constante, com o auxílio de uma lixa de carbeto de silício, número 800. Após, este dente foi preparado com uma broca diamantada número 2294 (KG Sorensen) em alta rotação, própria para a preparação de cavidades padronizadas para ensaios de laboratório, apresentando um limitador de penetração. Em seguida, com um motor de baixa rotação foi realizado o acabamento das paredes, obtendo-se uma cavidade de 2,0 mm de profundidade por 9,0 mm de diâmetro. Pela palatina desse dente, com uma broca carbide cilíndrica de numeração 2056 (KG Sorensen), fez-se uma penetração até se obter uma parede de dentina extremamente fina, porém sem que esta fosse rompida. Assim, com uma agulha, fez-se uma pequena perfuração no centro dessa dentina para que este instrumental servisse como um pino para remoção do corpo de prova de dentro da matriz de dente. Os corpos de prova (CP) foram obtidos a partir da inserção do compósito no interior da perfuração das matrizes em um único incremento e cobertos na superfície externa com uma matriz de poliéster mais uma lamínula de vidro. Os CP foram fotopolimerizados por 40 s pela fonte de luz halógena Optilux 501 (Demetron), com 500 mW/cm. Imediatamente após a polimerização, os corpos de prova eram submetidos no topo e na base para a análise de espectrometria no infravermelho para a determinação da profundidade de polimerização, pela técnica do filme vazado para o compósito não polimerizado e pela técnica da pastilha de brometo de potássio (KBr) para o compósito polimerizado. Foram confeccionados 5 CP de cada grupo. Em cada grupo, o compósito da base e do topo das amostras foi moído até se obter de 1,5 a 2,0 mg de pó e misturado com 70 mg de KBr, para obtenção da pastilha de KBr. Foi feita a análise de espectrofotometria no infravermelho por Transformada de Fourier (FTIR). As absorções selecionadas para o cálculo foram 1610 cm-1 e 1637 cm-1, os picos dos espectros das ligações dos carbonos aromáticos e alifáticos, respectivamente. Os dados obtidos foram tratados estatisticamente. Os grupos Gr1B, Gr2B, Gr3B e Gr4B representam, respectivamente, as bases dos CP confeccionados pelas matrizes de DB, TN, TB e AI. Já os Gr1T, Gr2T, Gr3T e Gr4T representam os topos. Médias (%) e DP: Gr1T (46,461,99), Gr2T (39,864,51), Gr3T (44,053,44) e Gr4T (38,045,08). Gr1B (40,441,49), Gr2B (36,153,81), Gr3B (40,093,18) e Gr4B (35,593,35). Em posse dos resultados, pôde-se concluir que os grupos do teflon negro, teflon branco e aço inoxidável não apresentaram diferenças entre o grau de conversão do topo e da base, enquanto que o grupo da dentina apresentou maior conversão do topo. Comparando as matrizes entre elas, pôde-se perceber que no topo, o GC do dente bovino é maior que o GC do aço inoxidável e do que o de teflon negro, o GC do teflon branco é maior que o GC do aço inoxidável e do que o de teflon negro. Já o topo dos grupos de dente bovino e teflon banco foram semelhantes. Nas bases dos CPs, não houve diferença significativa entre os grupos testados. De acordo com os resultados obtidos no experimento, pôde-se concluir que nos grupos do teflon negro, teflon branco e aço inoxidável não houve diferença entre 0 e 2 mm, ou seja, topo e base, o que mostra que o material de confecção da matriz não influênciou o grau de conversão do compósito. Já para o grupo da matriz de dentina, o topo apresentou valor de conversão monomérica maior, mostrando que, neste caso, o material da matriz interferiu no grau de conversão. Pode-se perceber também que existe uma tendência da matriz de teflon branco se assemelhar mais a matriz de dentina, pois foi o único grupo que apresentou semelhança nos valores de conversão monomérica no topo das amostras. Porém analisando a base das amostras, percebe-se que todos os grupos se comportaram de forma semelhante, obtendo valores do grau de conversão sem diferença significante. / This study was undertaken in order to determine, in vitro, the influence of mould material by the degree of conversion in a composite, and assess which of the materials tested was more akin to an array of dentin. The assessment was made by examining the degree of conversion (DC). Three bipartite moulds were made of black Teflon, white Teflon and stainless steel. All of them had 10 mm of diameter and 2 mm of deep. To the control group it was used a bovine central incisor, which had its buccal face leveled off in a sander under refrigeration with help of sandpaper 800. After that, this tooth was prepared in high speed with a diamond bur 2294 (KG Sorensen). This bur is proper for preparing standardized cavities for laboratories tests, and has a flat end with stop. A cavity of 2 mm of deep for 9 mm of diameter was obtained by a low speed that made the walls finished. With a cylindrical carbide bur 2056 (KG Sorensen), through the tooth lingual, a penetration was made until an extremely thin wall of dentin was obtained. Thus, with a needle, a little perforation was made in the center of this dentin. The specimens were made dispensed the restorative material on a single increment. A strip of cellulose was placed on top and a glass slab was pressed on the top. The material was cured during 40 seconds by halogen light, Optilux 501 (Demetron), with 500 mW/cm. Immediately, after cured, the specimens were submitted, on the top and on the bottom, to analyze their degree of conversion by FTIR. For the uncured composite was used the technique of the film leaked and for the cured composite, the technique of the potassium bromide tablet (KBr). Five specimens of each group had been confectioned. In each group, the bottom and top composite of the samples was worn out until if getting of 1,5 the 2,0 mg of dust and mixed with 70 mg of KBr, for attainment of the tablet of KBr. The analysis of FTIR was made. The absorptions selected for the calculation had been 1610 cm-1 and 1637 cm-1, the peaks of the specters of the linkings of aromatical and alifatic carbons, respectively. The data had been treated statistical. It could be concluded that the groups of black Teflon, white Teflon and stainless steel had not presented differences between the degree of conversion of the top and the bottom, whereas the group of the dentin presented greater conversion of the top. Comparing the moulds between them, it could be noticed that in the top, the DC of the bovine tooth is greater that the DC of the stainless steel and black Teflon, the DC of white Teflon is greater that the DC of the stainless steel and black Teflon. The top of the groups of bovine tooth and black teflon been similar. In the bottoms of the specimens, it did not have significant difference between the tested groups. In accordance with the results gotten in the experiment, could be concluded that in the groups of black Teflon, white Teflon and stainless steel it did not have difference between 0 and 2 mm, that is, top and bottom, its means that the material of mould confection did not influence the degree of conversion of the composite. Already for the group of the dentin, the top presented value of bigger conversion, showing that, in this in case that, the material of the matrix intervened with the DC. It can also be perceived that a trend of the white Teflon mould to resemble more the dentin mould, therefore was the only group that presented similarity in the values of DC in the top of the samples. However analyzing the bottom of the samples, all the groups had values of the degree of conversion without significant difference.

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