The dual-writing process of holographic technique was applied to fabricate the two-dimensional surface relief gratings on azo-dye doped polymer film in this study. The structure of two-dimensional grooves was investigated under the various polarization state of writing beam, the various angle between two stages of writing, and the adoption of nematic liquid crystals as the interface. The results revealed that the depth of two-dimensional surface relief gratings produced by the writing beams with P-polarization and the interface of nematic liquid crystals in contact with azo-dye polymer film was about 2~3 times of that without nematic liquid crystals as the interface. As the angle between two stages of writing increases, the first order diffraction efficiency and the depth of surface relief structure in the second writing becomes smaller for the writing beam with S polarization; while the first order diffraction efficiency and the depth of surface relief structure becomes larger for the writing beam with P polarization.

In this research, the polarization converters were manufactured by impinging intensity-gradient-distribution laser on DDLC (dye-doped liquid crystal) samples, which the gradient distributed light intensity was produced by applying linear variable ND filter. The performances of these polarization converters were demonstrated, which can convert a linear polarized incident light into a circular polarized light or an elliptic polarized light. The influence of cell gap and beam size of probe beam on the DDLC polarization converter has been discussed.

Xenobiotic compounds, which are exclusively man made, are produced in large quantities every year and released to the environment. Besides, anaerobic sludge digestion offers advantage in co-treatment of hazardous substances produced by the industry. The performance of the digesters can be monitored by modeling efforts. In this study, Anaerobic Digestion Model No.1 (ADM1) was calibrated, and validated for full-scale digester, lab-scale digester, and lab-scale digester seeded with totally different anaerobic biomass than that of full-scale digester. The model xenobiotic compound, a mono azo dye RO107, was co-treated with sewage sludge in an anaerobic digester. High removal efficiencies as 98% was found for azo dye at standard operating conditions of anaerobic digesters. The digester performance was not effected from azo dye or its reduction products. The dye reduction mechanism was modeled by biochemical mechanism due to unspecific enzymes and by chemical mechanism due to sulfide reduction. Some of the dye metabolites were suggested to be degraded by aerobic biotreatment. The anaerobic reduction metabolites of RO107 were identified as 2-(4-aminophenylsulfonyl) ethanol and 2,5-diamino-4-formamidobenzenesulfonic acid, and sulfanilic acid.

The laser-induced holographic gratings in the Azo dye-doped PMMA thin films with liquid crystal were investigated by changing the temperature of the sample, the angle of two writing beams and the rubbing. The high power Q-switch pulse laser has been used as the writing beams and the He-Ne cw laser has been used as a real-time probe beam to detect the first order diffraction singals. The grating are the results of photo-isomerization of azo dye and diffusions of liquid crystal. The model has been established to analyze the first order diffraction signals in order to understand the mechanism of grating and the effect of temperature and angle.

This work discusses the effect of photo-alignment in a liquid-crystal film that is doped with nanoparticles and azo-dye. The vertical alignment that is induced by nanoparticles of polyhedral oligomeric silsesquioxanes can be changed into homogeneous alignment by the absorption of photo-excited azo-dye. Both electro-optical and surface properties are analyzed to confirm this phenomenon. An electrically tunable polarization-dependent LC phase grating is produced using the method. By this method, we also present a transflective liquid crystal display with a single cell-gap in a dual-alignment configuration. This dual structure was fabricated via a single-step laser-light exposure through a photomask. The vertical alignment induced by nanoparticles of polyhedral oligomeric silsesquioxanes can be changed into a homogeneous alignment via absorption of photo-excited azo dye. The LC molecules at the transmissive and reflective pixels are homogeneous and hybrid alignment, respectively, at which optimal phase retardations of half and quarter wavelengths are achieved. Both nanoparticle- and azo-dye-induced vertical and homogeneous alignments are non-contact alignment processes and have potential for practical application.

Neste trabalho foi estudada a degradação eletroquímica do azo corante Preto Ácido 210 (PA210) utilizando ânodos dimensionalmente estáveis de composição Ti/Ir0,10Sn0,90O2 e Ti/Ir0,30Sn0,70O2 preparados pelo método de decomposição térmica de precursores poliméricos. Os efeitos da presença e da concentração de cloreto, da composição eletródica, da densidade de corrente e do tempo de eletrólise sobre a oxidação eletroquímica de 100 ppm do corante PA210 foram avaliados. Em todas as condições estudadas, a remoção da absorbância em 465 nm (max) foi superior a 94% depois de 30 min de eletrólise. A redução de TOC foi proporcional à concentração de íons cloreto no eletrólito e não mostrou dependência da composição eletródica. A formação de espécies organocloradas variou na faixa de 8 a 16 ppm, sendo que as maiores concentrações de AOX foram obtidas para o eletrólito com maior concentração de cloreto. A redução máxima de TOC obtida foi de 25% depois de 90 min de eletrólise à densidade de corrente de 25 mA cm-2 para o eletrólito HCl 0,1 mol L-1. A eficiência de corrente foi calculada em relação ao TOC, sendo obtido o melhor resultado, de 9,14%, em 30 min de eletrólise com HCl 0,1 mol L-1 a 25 mA cm-2, sendo esta eficiência quatro vezes maior que para melhor eficiência em meio de H2SO4 0,1 mol L-1. O estudo da relação TOC / AOX indica que após as eletrólises houve a adição de cloreto as substâncias orgânicas gerando espécies organocloradas que apresentam uma relação de aproximadamente 1 átomo de cloro para cada 5 átomos de carbono. / The electrochemical degradation of the azo dye Acid Black 210 (AB210) using dimensionally stable anodes of composition Ti/Ir0,10Sn0,90O2 and Ti/Ir0,30Sn0,70O2 prepared by thermal decomposition of polymeric precursors was studied. The effects of the presence and concentration of chloride, electrode composition, current density, and electrolysis time on the electrochemical oxidation of 100 ppm dye PA210 were evaluated. In all the studied conditions, the removal of the absorbance at 465 nm (max) was greater than 94% after 30 min of electrolysis. The reduction of TOC was proportional to the concentration of chloride ions in the electrolyte and was not shown to be dependent on electrode composition. The formation of organochloride species varied in the range from 8 to 16 ppm, with higher concentrations of AOX being obtained for the electrolyte with high chloride concentration. The maximum reduction of TOC was 25% after 90 min of electrolysis, at a current density of 25 mA cm-2, for the electrolyte HCl 0.1 mol L-1. The current efficiency was calculated in relation to TOC, and the best result was 9.14% after 30 min of electrolysis in HCl 0.1 mol L-1 at 25 mA cm-2. This efficiency is four times higher than the best efficiency obtained by using only H2SO4 0.1 mol L-1 as electrolyte. The study of the TOC / AOX relationship indicates that there was addition of chloride to the organic substances after electrolysis, thus genetaring organochloride species with a ratio of about 1 atom of chlorine for every 5 carbon atoms.

No description available.

Este estudo teve como objetivo o uso de Processos Oxidativos Avançados (POA\'s), para a descoloração e degradação dos corantes azo (Congo Red) e (Acid Yellow 42) em solução aquosa, sendo realizado em escala de bancada (processo batelada), utilizando-se reator tubular. Utililizou-se o Processo Oxidativo Avançado UV/H2O2, avaliando a influência dos seguintes fatores: concentração dos corantes, pH, temperatura, concentração do H2O2, concentração do NaCl e concentração do Na2SO4. Para a otimização dos parâmetros utilizados nas oxidações dos corantes, um planejamento estatístico (Método Taguchi) foi empregado para selecionar os de melhor eficiência para a efetivação do processo proposto. A forma de verificação dos resultados (fator de resposta) foi mediante a análise da redução do sinal de Absorbância dos corantes, após cada tratamento, pelo método espectrofotométrico, e da redução de TOC. Os resultados mostraram que o processo utilizando o POA contribuiu em uma redução de 96,0 % na Absorbância e 54 % no TOC para o Corante Congo Red e redução de 99,8 % na Absorbância e 85 % no TOC para o Corante Acid Yellow 42. / The aiming of this study was the use of Advanced Oxidation Processes (AOP\'s) to decoloration and degradation of azo dye Congo Red and Acid Yellow 42 (solution aqueous). This process was realized in laboratory scale employing a tubular reactor. The influence of the factors: H2O2, NaCl, and Na2SO4 concentrations, temperature and pH was evalueted. The statistical tool employed to optimize the process was the Taguchi Method. The response factor of this analysis was the reduction of dye absorbance by spectrophotometric. The results showed that AOP\'s contributed to dye reductions of respectively 96% reduction of absorbance and 54 % reduction of TOC to Congo Red ; 99,8% reduction of absorbance and 85% reduction of TOC to Acid Yellow 42.

Este estudo teve como objetivo o uso de Processos Oxidativos Avançados (POA\'s), para a descoloração e degradação dos corantes azo (Congo Red) e (Acid Yellow 42) em solução aquosa, sendo realizado em escala de bancada (processo batelada), utilizando-se reator tubular. Utililizou-se o Processo Oxidativo Avançado UV/H2O2, avaliando a influência dos seguintes fatores: concentração dos corantes, pH, temperatura, concentração do H2O2, concentração do NaCl e concentração do Na2SO4. Para a otimização dos parâmetros utilizados nas oxidações dos corantes, um planejamento estatístico (Método Taguchi) foi empregado para selecionar os de melhor eficiência para a efetivação do processo proposto. A forma de verificação dos resultados (fator de resposta) foi mediante a análise da redução do sinal de Absorbância dos corantes, após cada tratamento, pelo método espectrofotométrico, e da redução de TOC. Os resultados mostraram que o processo utilizando o POA contribuiu em uma redução de 96,0 % na Absorbância e 54 % no TOC para o Corante Congo Red e redução de 99,8 % na Absorbância e 85 % no TOC para o Corante Acid Yellow 42. / The aiming of this study was the use of Advanced Oxidation Processes (AOP\'s) to decoloration and degradation of azo dye Congo Red and Acid Yellow 42 (solution aqueous). This process was realized in laboratory scale employing a tubular reactor. The influence of the factors: H2O2, NaCl, and Na2SO4 concentrations, temperature and pH was evalueted. The statistical tool employed to optimize the process was the Taguchi Method. The response factor of this analysis was the reduction of dye absorbance by spectrophotometric. The results showed that AOP\'s contributed to dye reductions of respectively 96% reduction of absorbance and 54 % reduction of TOC to Congo Red ; 99,8% reduction of absorbance and 85% reduction of TOC to Acid Yellow 42.

Dyes for inkjet printing are typically of the chromonic type. Chromonic mesophases have gained considerable attention as a well-defined group of lyotropic mesogens with different properties from conventional amphiphiles. While extensive research has been dedicated to the field of surfactant liquid crystals, structural and aggregation studies of chromonics have only emerged as a topic of interest within the last few years. The liquid crystalline structures in aqueous solutions of commercial Cu - phthalocyanine and black dyes have been examined using a combination of optical microscopy, UV-vis spectroscopy, nuclear magnetic resonance, wide- and small-angle X-ray diffraction and electronic paramagnetic resonance with a view to examining the phase behaviour of the chromonic mesophases formed over a broad range of concentrations and temperatures. These studies were performed in order to resolve outstanding problems concerning structural properties of these systems. Optical microscopy allowed us to identify the liquid crystalline phases and to construct the phase diagram. The observations show that both of these dyes form nematic mesophase above 15% wt / wt% dye. The small-angle diffraction data confirmed that the nematic phase for the black dye is maintained throughout the 16-25% composition range. A further increase in concentration leads to the formation of the hexagonal phase. The Cu – phthalocyanine dye also formed a nematic phase at low concentrations, with the aggregates undergoing a phase transition to an orientationally ordered chromonic liquid crystal phase at high dye concentration. These studies showed that this ordered phase possessed hexagonal symmetry. The wide-angle X-ray results demonstrated that aggregation involved π-π stacking of the molecules into columns. An additional reflection at ca. 6.8Å was observed for the black dye, which is believed to arise from “head – to – tail” packing of the molecules within the aggregates (a similar phenomenon observed in other azo dyes, e.g. Edicol Sunset Yellow).The densities of both dyes were measured over the studied range of concentrations. This enabled us to calculate the parameters of the aggregates within the hexagonal mesophase. A comparison between the area of the molecule and the cross-section of the aggregates showed that the aggregates of both dyes were the unimolecular stacks.