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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.
291

Corantes naturais das cascas das árvores Stryphnodendron adstringens (Mart.) Coville e Croton urucurana Baill., nativas do Brasil: extração, tingimento, solidez de cor e caracterização do efluente / Natural dyes from trees barks Stryphnodendron adstringens (Mart.) Coville and Croton urucurana Baill., native to Brazil: extraction, dyeing, color fastness and wastewater characterization

Silva, Patrícia Muniz dos Santos 27 September 2018 (has links)
Esse trabalho objetivou investigar o potencial dos extratos aquosos das cascas de barbatimão (Stryphnodendron adstringens (Mart.) Coville) e sangra dágua (Croton urucurana Baill.) como corante natural têxtil. Os extratos foram caracterizados quanto ao pH, o teor de sólidos totais e a estabilidade no armazenamento. Os extratos foram liofilizados e avaliados por espectroscopia no infravermelho com transformada de Fourier (FTIR), termogravimetria (TG) e calorimetria exploratória diferencial (DSC). Foram realizados experimentos preliminares de tingimento em tecidos multifibra e em diferentes concentrações dos extratos. A partir desses experimentos, foram definidas as variáveis temperatura, tempo e concentração do extrato para o estudo do tingimento por planejamento experimental 2³, em tecidos 100 % algodão e 100 % lã. Os tecidos tingidos em condição otimizada, sem e com mordentes metálicos, foram avaliados quanto à cor, a solidez de cor à luz, à lavagem, à fricção e ao suor. Os efluentes foram coletados e caracterizados quanto ao pH, turbidez, sólidos totais dissolvidos (STD), oxigênio dissolvido, demanda bioquímica de oxigênio (DBO), demanda química de oxigênio (DQO) e teores de ferro e alumínio dissolvidos. Foram conduzidos ensaios bacteriológicos nos extratos aquosos, etanólicos e liofilizados e nos tecidos tingidos. Os resultados das análises por FTIR indicaram a presença de taninos, lignina e celulose nos extratos. Pelo estudo de estabilidade os extratos possuem duração de 42 dias. Nas análises por TG, os extratos obtiveram perda de massa total similares e não geraram alteração na degradação dos tecidos tingidos. Na análise por DSC os extratos obtiveram picos endotérmico e exotérmixo em temperaturas próximas. As melhores condições para o tingimento dos tecidos avaliados é em 98 °C, por 60 min e na concentração de 100 % do extrato. A solidez de cor dos tecidos tingidos variou de baixa a excelente. Os extratos liofilizados apresentaram propriedades antibacterianas. Os efluentes apresentaram valores de STD, DBO, DQO e alumínio e ferro dissolvidos acima dos limites determinados pela legislação nacional. De modo geral, os resultados obtidos indicam que os extratos das cascas de barbatimão e sangra dágua são promissores para serem utilizados como corantes naturais têxteis / This research aimed to investigate the potential of aqueous extracts of barbatimão (Stryphnodendron adstringens (Mart.) Coville) and sangra dágua (Croton urucurana Baill.) bark as natural textile dyes. The extracts were characterized for pH, total solids content and storage stability. The extracts were lyophilized and evaluated by Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG) and differential scanning calorimetry (DSC). Preliminary dyeing experiments were carried out on multifiber fabrics and at different extracts concentrations. From these experiments, the variables temperature, time and concentration of the extract for the study of dyeing by experimental design 2³ in 100 % cotton and 100 % wool fabrics were defined. Fabrics dyed in optimized condition, using metal mordants and with no mordents, were evaluated by colorimetry, color fastness to light, wash, rubbing and perspiration. The effluents were collected and characterized by pH, turbidity, total dissolved solids (TDS), dissolved oxygen, biochemical oxygen demand (BOD), chemical oxygen demand (COD) and dissolved iron and aluminum contents. Bacteriological tests were conducted on aqueous, ethanolic and lyophilized extracts and on dyed fabrics. The results of the FTIR analysis indicated the presence of tannins, lignin and cellulose in the extracts. By the stability study were found that the extracts have a duration of 42 days. In the TG analyzes, the extracts obtained similar total mass loss and did not generate alteration in the degradation of the dyed fabrics. In the DSC analysis the extracts obtained endothermic and exotherm peaks at near temperatures. The optimized dyeing for the evaluated fabrics is at 98 °C for 60 min and at the concentration of 100 % of the extract. The color fastness of the dyed fabrics ranged from low to excellent. Lyophilized extracts showed antibacterial properties. The wastewater showed values of TDS, BOD, COD and aluminum and iron dissolved above the limits determined by national legislation. In general, the results indicate that barbatimão and sangra dágua extracts are promising for use as natural textile dyes
292

Distributed feedback sol-gel channel waveguide lasers.

January 2005 (has links)
Chen Fei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 86-92). / Abstracts in English and Chinese. / Acknowledgements --- p.i / List of publications --- p.ii / Abstract (In English) --- p.iii / Abstract (In Chinese) --- p.v / Table of contents --- p.vii / List of figures --- p.x / List of tables --- p.xiv / Chapter Chapter I --- Introduction --- p.1 / Chapter Chapter II --- Sol-gel channel waveguides --- p.6 / Chapter 2.1 --- General sol-gel process --- p.6 / Chapter 2.2 --- Dye-doped sol-gel zirconia and zirconia-ORMOSIL materials --- p.10 / Chapter 2.3 --- Fabrication of sol-gel channel waveguides --- p.15 / Chapter 2.3.1 --- General process of the photolithographic technique --- p.15 / Chapter 2.3.2 --- Channels in glass substrates by using photolithographic wet etching technique --- p.19 / Chapter 2.3.3 --- Channels in fused silica substrates by using photolithographic dry etching technique (Inductive-coupled plasma etching) --- p.24 / Chapter Chapter III --- Coupled-wave theory and experimental setup of distributed feedback channel waveguide lasers --- p.27 / Chapter 3.1 --- Coupled-wave theory of distributed feedback lasers --- p.27 / Chapter 3.2 --- Experimental setup --- p.33 / Chapter Chapter IV --- One-dimensional and two-dimensional optical waveguide analysis --- p.37 / Chapter 4.1 --- 1-D planar waveguide analysis --- p.37 / Chapter 4.2 --- 2-D channel waveguide analysis using the Marcatili method --- p.39 / Chapter 4.2.1 --- The Eypq modes: Polarization in the y direction --- p.42 / Chapter 4.2.2 --- The Eypq modes: Polarization in the x direction --- p.46 / Chapter 4.3 --- 2-D channel waveguide analysis using the effective index method --- p.48 / Chapter Chapter V --- Distributed feedback channel waveguide lasers tunable in the visible --- p.50 / Chapter 5.1 --- Rhodamine 6G-doped zirconia planar and channel waveguides --- p.51 / Chapter 5.2 --- Results and discussion --- p.56 / Chapter 5.3 --- Summary --- p.66 / Chapter Chapter VI --- Near infrared distributed feedback channel waveguide lasers --- p.68 / Chapter 6.1 --- LDS dye-doped zirconia-ORMOSIL planar and channel waveguides --- p.68 / Chapter 6.2 --- Results and discussion --- p.72 / Chapter 6.3 --- Summary --- p.80 / Chapter Chapter VII --- Summary --- p.81 / References --- p.86
293

Nonlinear optical interaction in dye-doped sol-gel silica =: 在染料滲雜之溶-凝膠硅的非線性光學相互作用. / 在染料滲雜之溶-凝膠硅的非線性光學相互作用 / Nonlinear optical interaction in dye-doped sol-gel silica =: Zai ran liao shen za zhi rong- ning jiao gui de fei xian xing guang xue xiang hu zuo yong. / Zai ran liao shen za zhi rong, ning jiao gui de fei xian xing guang xue xiang hu zuo yong

January 1996 (has links)
by Tong Wai Yin Alex. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaf 55). / by Tong Wai Yin Alex. / Acknowledgement / Biographical Sketch / Abstract / Table of contents / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Chapter 2 --- Nonlinear Optics in dye-doped solid --- p.4 / Chapter 2.1 --- Nonlinear Optics --- p.4 / Chapter 2.2 --- Photophysics of dye molecules --- p.6 / Chapter 2.3 --- Nonlinear effect in dye-doped solid --- p.8 / Chapter Chapter 3 --- Sol-Gel Silica --- p.11 / Chapter 3.1 --- The formation of dye-doped sol-gel silica --- p.11 / Chapter 3.2 --- The physical properties --- p.15 / Chapter 3.3 --- The optical properties --- p.16 / Chapter Chapter 4 --- Saturation Absorption --- p.18 / Chapter 4.1 --- Saturation Absorption in Fluorescein 548 dye-doped solid --- p.18 / Chapter 4.2 --- Experimental Details --- p.19 / Chapter 4.3 --- Results and Discussion --- p.19 / Chapter 4.4 --- Conclusion --- p.30 / Chapter Chapter 5 --- Optical Phase Conjucation --- p.31 / Chapter 5.1 --- OPC Theory --- p.31 / Chapter 5.11 --- The Distortion Correction Theorem --- p.32 / Chapter 5.12 --- The Proof of the Distortion Theorem --- p.32 / Chapter 5.13 --- The generation of Phase Conjucate Waves --- p.34 / Chapter 5.2 --- Degenerate Four Wave Mixing --- p.35 / Chapter 5.21 --- Geometries of DFWM --- p.35 / Chapter 5.22 --- DFWM Theory --- p.37 / Chapter 5.23 --- DFWM in Absorbing Media --- p.40 / Chapter 5.3 --- Experimental Details --- p.44 / Chapter 5.4 --- Results and Discussion --- p.46 / Chapter 5.5 --- Conclusion --- p.53 / Chapter Chapter 6 --- Conclusion and Suggestions for future work --- p.54 / Reference
294

Distributed feedback zirconia and zirconia-ORMOSIL waveguide lasers.

January 2003 (has links)
Wang Jun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 74-79). / Abstracts in English and Chinese. / Acknowledgements --- p.i / List of publications --- p.ii / Abstract (In English) --- p.iii / Abstract (In Chinese) --- p.v / Table of contents --- p.vii / List of figures --- p.x / List of tables --- p.xiv / Chapter Chapter I --- Introduction --- p.1 / Chapter Chapter II --- Dye-doped sol-gel zirconia and zirconia-organically modified silicate waveguides --- p.6 / Chapter 2.1 --- General sol-gel process --- p.6 / Chapter 2.2 --- Dye-doped sol-gel zirconia and zirconia-ORMOSIL waveguides --- p.7 / Chapter Chapter III --- Basic theory and experiment setup of distributed feedback waveguide lasers --- p.13 / Chapter 3.1 --- Coupled-wave theory of distributed feedback lasers --- p.13 / Chapter 3.2 --- Introduction on the theory of planar optical waveguide --- p.16 / Chapter 3.3 --- Experiment setup design of DFB waveguide lasers --- p.19 / Chapter Chapter IV --- Zirconia and zirconia-organically modified silicate distributed feedback waveguide lasers tunable in the visible --- p.23 / Chapter Chapter V --- Tunable multi-wavelength distributed feedback zirconia waveguide lasers --- p.35 / Chapter 5.1 --- Brief introduction on multi-wavelength lasers --- p.35 / Chapter 5.2 --- R6G-doped zirconia multi-mode waveguides --- p.36 / Chapter 5.3 --- Experimental results and discussion --- p.39 / Chapter 5.3.1. --- Dual- and quadruple-wavelength DFB waveguide lasers --- p.39 / Chapter 5.3.2. --- The dispersion characteristics of multi-wavelength DFB waveguide lasers --- p.44 / Chapter 5.3.3. --- Determination of waveguide parameters by the DFB technique --- p.48 / Chapter 5.4 --- Summary --- p.51 / Chapter Chapter VI --- Distributed feedback laser action in sol-gel glass symmetric waveguides --- p.53 / Chapter 6.1 --- The fabrication of dye-doped glass symmetric waveguides --- p.54 / Chapter 6.2 --- Experimental results and discussion --- p.56 / Chapter 6.2.1. --- DFB laser action in sol-gel glass symmetric-asymmetric waveguide --- p.56 / Chapter 6.2.2. --- Dispersion characteristics of DFB symmetric and asymmetric waveguide lasers --- p.61 / Chapter 6.3 --- Summary --- p.65 / Chapter Chapter VII --- Summary --- p.69 / References --- p.74
295

Dynamics of hippocampal networks revealed by voltage sensitive dye imaging / Dynamiques des réseaux hippocampiques révélées par imagerie de coloration sensible au potentiel (VSDI)

Colavita, Michelangelo 18 December 2015 (has links)
Dans le but de mieux comprendre le fonctionnement du cerveau nous devons examiner les domaines structuraux qui le composent, de la simple cellule à des régions entières du cerveau interconnectées. Cependant, bien que le fonctionnement d’une ou plusieurs cellules soit relativement bien connu, il n’y a que peu d’informations concernant les groupements de neurones interagissant fonctionnellement dans une même tâche, les réseaux neuronaux. De plus, l'activité équilibrée et concertée des réseaux excitateurs et inhibiteurs joue un rôle clé pour les intégrations corticales appropriées. Par ailleurs, il existe plusieurs outils afin d’enregistrer l’activité des réseaux excitateurs, ce qui n’est pas le cas pour les réseaux inhibiteurs. L’imagerie du colorant sensible au voltage (VSDI) est une technique permettant l’enregistrement de l’activité neuronale au moyen d’une émission de fluorescence proportionnelle au changement de potentiel de membrane. Par rapport aux autres techniques employant des électrodes, le VSDI permet l’enregistrement non invasif de l’activité de centaines de sites en même temps. Au cours des dernières décennies, le VSDI a été largement utilisé tant in vitro qu’in vivo pour étudier l’activité d’une cellule et des réseaux excitateurs. Néanmoins, en utilisant le VSDI, les recherches quant à l’activité des réseaux excitateurs ont été principalement réalisées par quantification d’émission de fluorescence en définissant des régions d’intérêts à des temps fixes, alors que l’activité inhibitrice n’a été évaluée qu’à l’échelle cellulaire. La première approche ne permet pas l’obtention de toutes les informations de la dynamique de propagation de la transmission glutamatergique du fait qu’elle ne prend en considération ni la vitesse ni la direction de propagation du signal. En revanche, la seconde approche n’offre pas la possibilité d’étudier l’activité du réseau inhibiteur ce qui serait toutefois important de définir du fait de la propagation spatiale extensive des interneurones au sein des aires corticales. Durant mon doctorat, le but de mon travail a été d’étudier en détail les réseaux neuronaux excitateurs et inhibiteurs de l’aire CA1 de l’hippocampe de souris à l’aide du VSDI. Pour les étudier de façon plus compréhensive, en collaboration avec une équipe de mathématicien, nous avons développé un algorithme permettant de mesurer la vitesse et la direction de propagation du signal VSDI, ce qui représente une nouvelle méthode pour analyser le flux optique. Après la validation réussie de l’algorithme avec des données de substitution pour tester sa précision, nous avons analysé deux séries d’expériences dans lesquelles l’activité des réseaux excitateurs a été manipulée soit par augmentation de l’intensité de stimulation passant de 10 à 30 Volts ou en bloquant la transmission GABAergique avec la picrotoxine, un antagoniste du récepteur GABAA. Les résultats de ces manipulations montrent une diminution significative de la vitesse alors que l’application de picrotoxine modifie de façon significative la direction de propagation, ce qui rend le signal de dépolarisation médié par le VSDI moins dispersé par rapport au contrôle. L’utilisation du VSDI a permis l’entière caractérisation des signaux hyperpolarisants médiés par les récepteurs GABAA dans toutes les sous-couches de CA1 (champ IPSP), offrant ainsi une nouvelle façon d’étudier les événements inhibiteurs à l’échelle d’un réseau. De plus, j’ai montré qu’en activant les récepteurs mGluR5, j’étais capable d’augmenter de façon durable le champ IPSP du VSDI, avec la durée et l’ampleur au niveau des sous-couches spécifiques de CA1. Globalement, je présente dans cette thèse de nouvelles méthodes et nouveaux résultats qui peuvent représenter une avancée dans la quête d’une meilleure compréhension des réseaux neuronaux, excitateurs et inhibiteurs, ce qui, espérons-le, pourra contribuer à réduire l’écart de connaissance entre l’activité d’une seule cellule et celle du comportement. / In order to better understand brain functioning we need to investigate all the structural domains present in it, from single cell to interconnected entire brain regions. However, while our knowledge in terms of single/few cells functioning is vast, very little is known about neuronal networks, which are interacting collections of neurons functionally related to the same task. Moreover, the balanced and concerted activity of excitatory and inhibitory networks plays a key role for proper cortical computations. However, while exist several tools to record excitatory networks activity, this is not the case for inhibitory networks. Voltage sensitive dye imaging (VSDI) is a technique that allows the recording of neuronal activity by mean of proportional emission of fluorescence according to changes in membrane potential. The advantage of using VSDI over other recording techniques using electrodes is that VSDI allows not invasive recording of neuronal activity from hundreds of sites at the same time. During my doctoral course I aimed at studying in detail excitatory and inhibitory neuronal networks in the CA1 area of mouse hippocampus with VSDI. To study excitatory networks more comprehensively, in collaboration with a team of mathematicians, we developed a mathematical algorithm that allowed measuring the velocity and the direction of spreading of the VSDI signal and it represents a new method to determine an optical flow. After successful validation of the algorithm with surrogate data to test its accuracy, we analysed two set of experiments in which network excitatory activity has been manipulated either by increasing Schaffer’s collaterals stimulation intensity or by blocking GABAergic transmission with the GABAA receptor antagonist picrotoxin in order to increase the depolarization in the CA1 region of the hippocampus. The results of these manipulations significantly decreased signal velocity whereas picrotoxin application significantly modified the direction of spreading, making the depolarization-mediated VSDI signal less dispersed compared to control. Using VSDI I was able to fully characterize GABAA receptor-mediated hyperpolarizing signals in all the CA1 sublayers (field IPSPs), thus providing a new way of monitoring inhibitory events at network level. Moreover, I found that the activation of mGluR5 receptors induced an increase in a long-lasting manner of the VSDI-recorded field IPSPs, with duration and magnitude that relied on the specific CA1 sublayer considered. Overall, my work shows new methodologies and new findings that may represent a step forward in the quest for a better understanding of neuronal networks, both excitatory as well as inhibitory, which hopefully can contribute to reduce the gap of knowledge between single cell activity and behaviour.
296

New functional molecules and polymers for organic light-emitting diodes and solar cells

Wang, Qiwei 01 January 2010 (has links)
No description available.
297

Produção e avaliação da farinha da casca de banana como bioadsorvente na remoção de corantes têxteis em águas residuárias

Sousa, Dennis Dantas de 20 June 2015 (has links)
Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2016-03-10T14:22:02Z No. of bitstreams: 1 PDF - Dennis Dantas de Sousa.pdf: 1176250 bytes, checksum: 9d455113be8bf6871e88e82e6a4fccb3 (MD5) / Made available in DSpace on 2016-03-10T14:22:02Z (GMT). No. of bitstreams: 1 PDF - Dennis Dantas de Sousa.pdf: 1176250 bytes, checksum: 9d455113be8bf6871e88e82e6a4fccb3 (MD5) Previous issue date: 2015-06-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The textile sector is known for the large use of chemicals and its high power to contamination of water resources due to the generation of large quantities of wastewater. This work aimed to produce and evaluate the flour banana peel as an adsorbent for the removal of textile dyes. The adsorbent was obtained by drying in an hothouse with air circulation banana peels cut into cubes, in different operating conditions of temperature, mass, and drying time. The adsorption kinetic tests were performed in finite bath using 2.5 g of biomass and a dye solution blue cassafix CA-2G, with a concentration of 200 mg.L -1 . In the study adsorption equilibrium was used 0.25g of banana peel flour and different concentrations of the dye solution ranging from 25 mg.L -1 and 200 mg.L -1 , with the contact time of 8 hours, under agitation of 80 rpm in finite bath. According to the statistical analysis of the experimental design 2 3 drying showed that factors (mass, time, temperature) are all statistically significant, and that the obtained model is statistically significant, considering that F (calculated) is larger than the F (tabulated). Among the models tested for the drying process the one that best adjusted the experimental data was the model proposed by Midili, common coefficient of determination (R 2 ) above 0.96 for all drying tests. It was found that the adsorbent with lower moisture levels, provides better dye removal efficiencies. In this work was obtained removal efficiency around 50% using a residence time of 60 minutes. The kinetic model of pseudo-second order showed better comparison of the experimental data, with determination coefficients above 0.97. The equilibrium isotherm model that best fit the experimental data obtained in the adsorption was the model proposed by Sips, obtaining coefficient of determination the value of 0.97047, showing that the adsorption cooperatively. The banana peel flour is a byproduct agro-industrial low-cost which proves to be an adsorbent potential for removing textile dye studied. / O setor têxtil é conhecido pela grande utilização de produtos químicos e seu elevado poder de contaminação dos recursos hídricos. Este trabalho teve por objetivo produzir e avaliar a farinha da casca de banana como adsorvente na remoção de corantes têxteis. O adsorvente foi obtido através de secagem em estufa com circulação de ar das cascas de banana em diferentes condições operacionais de temperatura, massa e tempo de secagem, e em seguida foram trituradas para se obter a farinha. Os ensaios cinéticos de adsorção foram realizados em banho finito utilizando 2,5g da farinha da casca de banana e uma solução de corante azul cassafix CA-2G, com uma concentração de 200 mg.L . No estudo do equilíbrio de adsorção utilizou-se 0,25g da farinha da casca de banana e diferentes concentrações da solução de corante variando entre 25 mg.L 1 e 200 mg.L -1 , com tempo de contato de 8h, sob agitação de 80rpm em banho finito. De acordo com a análise estatística do planejamento fatorial de 2 da secagem revelou que os parâmetros operacionais (massa, tempo, temperatura) são todos estatisticamente significativos e que o modelo obtido é estatisticamente significativo, tendo em vista que o F(calculado) é maior que o F(tabelado). Dentre os modelos testados para o processo de secagem o que melhor se ajustou aos dados experimentais foi o modelo proposto por Midili, com um coeficiente de determinação (R 2 ) acima de 0,96 para todos ensaios de secagem. Foi possível constatar que o bioadsorvente com menores teores de umidades, apresenta melhores eficiências de remoção do corante. Obteve-se eficiência de remoção em torno de 50%, usando-se tempo de rotação de 60 minutos. O modelo cinético de pseudo-segunda ordem apresentou melhor concordância com os dados experimentais, apresentando coeficientes de determinação de 0,97. O modelo de isoterma de equilíbrio que melhor se ajustou aos dados experimentais obtidos na adsorção foi o modelo proposto por Sips, obtendo coeficiente de determinação de 0,97, mostrando que a adsorção de forma cooperativa. A farinha da casca de banana é um subproduto agroindustrial de baixo custo que demonstra.
298

Estudo de propriedades ópticas não-lineares de cristal líquido dopado com corante em função da temperatura. / Studies of non-linear optical properties of dye doped liquid crystal in function of the temperature.

Jacinto da Silva Esteves 11 August 2000 (has links)
Com o objetivo de estudar os efeitos provocados pela adição de um corante em um cristal líquido termotrópico (CL), pesquisamos neste trabalho a influência da temperatura na reorientação das moléculas deste composto, bem como o índice de refração e a absorção não-linear, devido à presença de um campo eletromagnético. O CL estudado apresenta a reorientação de suas moléculas na presença de luz polarizada. Esta reorientação se deve à polarização provocada pelo campo eletromagnético da luz incidente nas moléculas do CL. O torque, que ocasiona tal reorientação, é denominado torque óptico Gammaopt. Quando estes CLs são dopados com determinados corantes, o campo incidente também interage com o corante, induzindo assim dipolos elétricos. Estes dipolos, por sua vez, interagem com as moléculas do CL provocando nelas um torque adicional Gammadye. Este torque adicional é proporcional ao torque óptico Gammadye = eta Gammaopt, onde eta é uma característica do corante denominado de fator de amplificação do torque óptico e depende da temperatura em que a amostra se encontra. A principal ferramenta do nosso estudo é a técnica de varredura z e, é através dela, que observamos a influência da temperatura nos efeitos não-lineares, refrativo e absortivo, exibidos pelas amostras. Através de tal técnica, calculamos, em função da temperatura, o fator de amplificação do torque óptico (eta); os índices de refração não-lineares (n2) devido à reorientação molecular da amostra, com e sem corante; e os coeficientes de absorção não-lineares (Beta) da amostra dopada devido a efeitos térmicos, de reorientação (torque) e de todos os efeitos somados. / With the objective of studying the effects due to the addition of a dye in a thermotropic liquid crystal (LC), we investigated in this work the influence of the temperature in the reorientation of the molecules of this compound, as well as the refraction index and the non linear absorption, in the presence of a electromagnetic field. The studied LC presents the reorientation of its molecules in the presence of polarized light. This reorientation is due to the polarization induced by the electromagnetic field of the incident light in the molecules of LC. The torque, that causes such reorientation, is named Gammaopt. When these LCs are doped with certain dyes, the incident field also interact with the dye, inducing electric dipoles. These dipoles, interact with the molecules of the LC producing an additional torque Gammadye. This additional torque is proportional to the optical torque Gammadye = eta Gammaopt, where eta is a characteristic of the dye, a factor of amplification of the optical torque, that is temperature dependent. The main tool of our study is the z-scan technique and, it is through it, that we observed the influence of the temperature in the non linear, refractive and absorptive effects, exhibited by the samples. Through this technique, we calculated, as a function of the temperature, the amplification factor of the optical torque (eta); the non linear refractive index (n2) due to the molecular reorientation of the sample, with and without dye; and the non linear absorption coefficient (Beta) of the doped sample due to thermal effects, of reorientation (torque) and of all the effects together.
299

Pigmentantes de gema: novo método de avaliação de cor e caracterização da produtividade e saúde das poedeiras / Yolk pigments: new method for evoluation of color and cheracteriztion of health and productivity of layers

Carneiro, Jussara de Souza 01 August 2013 (has links)
Submitted by Jaqueline Silva (jtas29@gmail.com) on 2014-10-06T19:08:19Z No. of bitstreams: 2 Tese - Jussara de Souza Carneiro - 2013.pdf: 1644698 bytes, checksum: 3faeafe59bfc34f56dc772cbdb1cf640 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2014-10-06T19:15:39Z (GMT) No. of bitstreams: 2 Tese - Jussara de Souza Carneiro - 2013.pdf: 1644698 bytes, checksum: 3faeafe59bfc34f56dc772cbdb1cf640 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-10-06T19:15:39Z (GMT). No. of bitstreams: 2 Tese - Jussara de Souza Carneiro - 2013.pdf: 1644698 bytes, checksum: 3faeafe59bfc34f56dc772cbdb1cf640 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-08-01 / Aimed at feeding laying hen, corn has been substituted by other cheaper food. However, since these foods have little capacity to stain egg yolk, pigments are usually added to the animal’s feed. Synthetic carotenoids, such as canthaxanthin, and the natural pigments present in bran annatto are among the most used food coloring. However, little is known about the impact of those pigments to the animal’s health, and it is important to point out that the choice of the dye and its dose are based solely on the eggs color. In the present study we aimed at evaluating if the pigments have some beneficial or toxic effects on the laying hen health, and test a new simple, fast and non subjective computerized method to analyze the egg color. Thus, laying hens of the ISA Brown lineage were fed with three different sorghum meal: without dye; with bran annatto (3%); or with cathaxanthin (8 ppm) + apocaroten (25 ppm). Animal performance, eggs quality, the liver and kidney functions, as well as the oxidative stress inferred from the levels of malondialdehyde in red blood cells were determined. None of the treatments altered the laying hen performance, the liver and kidney integrity and functions, and the oxidative stress. However, all the dyes tested increased yolks egg weight and color. Finally, the results clearly suggest that yolks color intensity was more accurately determined by the computerized method when compared to the traditional colorimetric fan assay. / O milho vem sendo substituído por outros alimentos na alimentação de galinhas poedeiras. Contudo, como tais alimentos apresentam baixa capacidade de corar as gemas dos ovos, pigmentantes são comumente adicionados à ração dos animais. Carotenóides sintéticos como cantaxantina, bem como pigmentos naturais encontrados no farelo de urucum estão entre os mais utilizados. Contudo, sabe-se muito pouco sobre o impacto da utilização de tais pigmentantes na saúde das galinhas, além da determinação da dose ser baseada somente na coloração das gemas dos ovos. No presente estudo avaliou-se se os pigmentantes apresentam algum efeito sobre a saúde das galinhas, bem como testou-se um novo método computadorizado, simples, rápido e não subjetivo, para a avaliação da coloração das gemas. Assim, galinhas poedeiras vermelhas foram alimentadas com três diferentes rações a base de sorgo: sem pigmentante; com 3% de farelo de urucum ou com cantaxantina (8 ppm) + apocaroteno (25 ppm). Foram avaliados o desempenho das galinhas, a qualidade dos ovos, as funções renais e hepáticas, e o estresse oxidativo (inferido a partir dos níveis de malondealdeído de eritrócitos). Nenhum dos tratamentos alterou o desempenho das galinhas, a qualidade dos ovos e as funções hepáticas e renais. Contudo, todos os corantes aumentaram a coloração e o peso das gemas dos ovos. Por fim, os resultados sugerem claramente que a intensidade da coloração das gemas foi determinada com maior precisão pelo método computadorizado quando comparado ao ensaio colorimétrico tradicional.
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ExtraÃÃo de pigmentos carotenÃides da carapaÃa do camarÃo e sua utilizaÃÃo em um produto derivado de pescado / Extraction of carotenoid pigments of the carapace of shrimp and their use in a by-product of fish

ErotÃide Leite de Pinho 10 September 2001 (has links)
CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior / O descarte na indÃstria de pescado, inclusive o de carapaÃas de crustÃceos, constitui um percentual bastante elevado. Estas cascas sÃo ricas em pigmentos carotenÃides, os quais, apresentam um alto valor de pigmentaÃÃo, sendo corrente em alguns paÃses a extraÃÃo e posterior utilizaÃÃo dos mesmos em raÃÃes. O objetivo deste experimento foi estudar a extraÃÃo dos pigmentos carotenÃides das cascas de camarÃo e verificar seu potencial de uso como aditivo natural de cor em um produto à base de pescado. Neste estudo foram desenvolvidos testes preliminares para escolha de um mÃtodo para a extraÃÃo dos pigmentos optando-se pela extraÃÃo com solvente. Caracterizou-se ospigmentos extraÃdos das cascas de camarÃo e avaliou-se a influÃncia do extrato pigmentado aplicado em um produto à base de pescado, o qual foi embalado à vÃcuo e sem vÃcuo e submetido à uma estocagem (-20ÂC) durante um perÃodo de60 dias. A cor dos produtos foi medida a cada 15 dias no sistema CIE determinando-se os parÃmetros de L*, a* e b*. A anÃlise espectrofotomÃtrica do extrato de camarÃo apresentou produtos de degradaÃÃo da astaxantina. Os produtos pigmentados com o extrato de camarÃo e embalados à vÃcuo apresentaram valores de luminosidade (L*) menores (p < 0,05) que os embalados sem vÃcuo com 15 e 45 dias de armazenamento. Para o componente de intensidade de cor amarela (b*) os produtos embalados à vÃcuo apresentaram valores maiores (p<0,05) no inÃcio do armazenamento (0 dias) e menores (p<0,05) com 45 dias de armazenamento, em relaÃÃo Ãqueles embalados sem vÃcuo. Contudo, no perÃodo de 60 dias de armazenamento nÃo foi observado efeito significativo da embalagem à vÃcuo sobre as caracterÃsticas de cor dos produtos. / Waste material in the fish industry including the shells from the crustacean, constitute a very high percentage. These shells are rich in carotenoids pigments, which may have a high pigmentation value when used in foods. It is common in some countries the use of the extracted pigments in feeds.The aim of this experiment was to study the process of carotenoids extraction and to verify its pigmenting potential in a minced fish food product. The solvent extraction technique was used after testing other extraction procedures. Extracted pigments were characterized by spectrophotometry. Pigments were then included in the fish formulation. Fish products were packaged with and without vacuum and storage in the dark at â20ÂC for 60 days. The color of the products was measured every 15 days with the CIE system which determines parameters L*, a* and b*. The spectrophotometry study showed products of degradation of astaxanthin in the shell extract. The luminosity (L*) of the color in products packaged under vacuum was lower (p<0.05) with 15 and 45 days of storage than in those stored without vacuum. Vacuum packaged products showed that with 0 days of storage the yellowness component (b*) was higher (p<0.05) in vacuum packaged products than in those stored without vacuum. The reverse occurring with 45 days of storage. After 60 days frozen storage vacuum packaging did not affect the color characteristics of the fish product.

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