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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.
401

Resíduo líquido do tratamento com vapor da madeira de Eucalyptus grandis Hill ex. Maiden, aplicado como corante têxtil natural / Liquid waste from steaming of Eucalyptus grandis Hill ex. Maiden wood as a natural dye source for textile fibers

Ticiane Rossi 12 February 2014 (has links)
Aspectos ligados à saúde humana e ao meio ambiente têm ampliado o interesse da sociedade pelo uso de corantes naturais. Nesse contexto, inclui-se o retorno ao uso de corantes provenientes de matérias-primas de base florestal. Uma fonte potencial encontra-se na operação industrial de tratamento da madeira de Eucalyptus grandis por vapor. Usualmente, o resíduo líquido gerado ao final do processo é descartado, porém, por possuir cor, seu potencial como um corante natural para fibras têxteis foi aqui investigado. Especificamente, o resíduo foi aplicado em tecidos de algodão, lã e nylon, considerando-se o processo de tingimento por esgotamento. Foram estudados os efeitos da concentração do corante, forma de aplicação, in natura e em pó, tempo, temperatura, pH do banho de tingimento, e adição de sais metálicos no tingimento. Foi avaliada a solidez da cor dos tecidos tingidos quanto à luz, lavagem doméstica e fricção. O estudo contemplou as avaliação das características físico-química do resíduo, nos quesitos pH, cor, cromatografia de camada delgada e teores de sólidos totais e taninos condensados. Os resultados indicaram o resíduo líquido apresentando cor marrom, pH ácido, teor médio de sólidos totais e taninos condensados, respectivamente, de 2,2% e 0,93%. Os resultados das análises de cromatografia de camada delgada sugeriram a presença do ácido tânico na composição do resíduo. Em relação aos resultados de solidez de cor, verificou-se uma boa resistência dos tecidos tingidos à lavagem doméstica e uma solidez de cor à luz típica dos corantes naturais. Observou-se ainda uma boa solidez à fricção, com destaque para o excelente índice de fricção a seco nas malhas de algodão. O resíduo líquido revelou-se como um corante natural, com potencial de aceitação pela indústria têxtil, visando o tingimento de algodão, lã e nylon. / Natural dyes are gaining interest due to their expected low risk to human health and the environment. A source of natural dye was found in industrial operation of steaming Eucalyptus grandis wood. The liquid waste generated at the end of the process has been discarded. Due to this fact and the intensity of the color of the product, it was emerged the idea of this study, considering natural dye for textile fabrics. The waste was used for dyeing cotton, nylon and wool by exhaustion dyeing process. The effects of the dye concentration, the application in liquid and powder form, time, temperature, pH of the dyeing bath and the addition of metal salts in the bath were evaluated. The physic-chemical characteristics of the waste as pH, color, thin layer chromatography, and total solids and condensed tannins were also investigated. The resulting dyed fabrics were evaluated for color fastness to light, domestic washing and rubbing. The waste showed brown color, acidic pH, average total solids content of 2.2% and content of condensed tannins of 0.93%. The results from thin layer chromatography of the residue suggested the presence of tannic acid in its composition. Regarding the color fastness, it was found a very good result considering domestic washfastness, with lightfastness typical of natural dyes. The rubbing fastness was good, especially for cotton, which presented excellent grades. It was possible to consider the liquid residue as product potentially destined to the textile industry, regarding the natural dyeing of cotton, nylon and wool.
402

Reutilização de banhos de tingimento de poliéster em batelada com corantes dispersos / Reuse of batch polyester dyebaths with disperses dyes

Andrade, Augusto Tairum de 20 September 2018 (has links)
Atualmente, a questão ambiental envolvendo a indústria têxtil, de modo principal, o segmento de beneficiamento têxtil vem sendo discutida em estudos e pesquisas. Dentro deste contexto, os corantes dispersos utilizados no tingimento de fibras de acetato de celulose, poliamida e poliéster podem ser considerados de grande grau de impacto ambiental devido sua grande utilização e sua alta toxicidade. O objetivo principal deste trabalho é avaliar a qualidade de malhas de poliéster fabricados com fios standard (167f48 dtex) e microfibra (167f144 dtex), tintas com corantes dispersos C.I Disperse Red 60 e C.I Disperse Blue 79 com a reutilização dos banhos de tingimento. Foram avaliadas a reprodutibilidade da cor (espectrofotômetro), a solidez à lavagem e à fricção. Os valores experimentais obtidos nos tingimentos do primeiro banho (água limpa) foram usados como referência para analisar a qualidade dos tecidos tintos nos banhos subsequentes. As análises dos resultados experimentais foram feitas usando a análise de variância (ANOVA) com um intervalo de confiança de 95%. Os resultados mostraram os tipos de fios e de corantes utilizados nas tingimentos influenciam significativamente na reprodutibilidade da cor. Entretanto, estes mesmos fatores não foram significativos para as análises de solidez à lavagem e à fricção. O fator banho não foi significativo para as características de qualidade verificadas nos tecidos tintos, indicando que existe viabilidade na reutilização dos banhos de tingimento destes corantes / Actually, the environmental issue involving the textile industry, mainly, the segment of textile processing has been discussed in studies and research. Within this context, disperse dyes used in the dyeing of cellulose acetate, polyamide and polyester fibers can be considered environmental high impact due to their big demand and high toxicity. The main objective of this work is to evaluate the quality of polyester fabrics made with standard yarns (167f48 dtex) and microfiber (167f144 dtex), disperse colorants C.I Disperse Red 60 and C.I Disperse Blue 79 with the reuse of the dyeing baths. Color reproducibility (spectrophotometer), washing fastness and friction fastness were evaluated. Experimental values obtained on dyeings from the first bath (clean water) were used as reference to analyze the quality of the red tissues in the subsequent baths. Analyzes of the experimental results were done using analysis of variance (ANOVA) with a confidence interval of 95%. The results showed the types of yarns and dyes used in dyeing significantly influence color reproducibility. However, these same factors were not significant for the wash and friction fastness analyzes. The bath factor was not significant for the quality characteristics verified in the red tissues, indicating that there is viability in the reuse of the dyeing baths of these dyes
403

Estudo das características espectroscópicas dos corantes ciânicos com dois cromóforos na interação com DNA: efeitos da força iônica. / Spectroscopic studies of bichromophoric cyanine dyes (BCD) in their interaction with DNA: effect of ionic strength.

Scháberle, Fábio Antonio 03 October 2002 (has links)
O câncer é uma patologia responsável por um grande número de óbitos. Os tratamentos convencionais, quimioterapia e radioterapia, nem sempre são eficientes e, além disso, os efeitos colaterais são intrínsecos às terapias. A partir da década de 70 surgiu uma nova forma de terapia chamada de “terapia fotodinâmica" (“Photodynamic Therapy", PDT) que apresenta poucos efeitos colaterais quando comparada com as terapias convencionais. O princípio da PDT é introduzir no organismo um composto fotoativo e irradiar com luz visível o local a ser tratado, obtendo assim a forma ativa do composto que induz a morte das células cancerígenas. Os compostos atualmente usados em PDT possuem algumas desvantagens na sua aplicação que estimula a busca de outros compostos mais satisfatórios. Neste projeto foram estudados corantes ciânicos com dois cromóforos (BCD) que possuem boas vantagem para uso em PDT. O trabalho foi focado no estudo das características espectrais e energéticas dos BCD na interação com DNA, e o efeito da força iônica nessa interação para sugerir seu uso em fotoquimioterapia, principalmente em PDT. Foram estudados quatro BCD que se diferenciam pelo ângulo entre os cromóforos. As análises experimentais foram feitas através de métodos espectroscópicos de absorção ótica, fluorescência e dicroísmo circular, e as teóricas através de programas computacionais comerciais e um programa desenvolvido neste trabalho. Os resultados obtidos mostram que os BCD possuem alta afinidade com as moléculas de DNA, formando diferentes espécies que afetam nas características dos seus estados excitados. A presença de outros íons influencia as características dos corantes e a sua interação com DNA. Pelos resultados obtidos podemos considerar que os BCD apresentam boas características para aplicação em PDT e que estes resultados dão suporte para estudos futuros da interação destes corantes com sistemas naturais (células) e para fazer testes clínicos em animais. / Cancer is a pathology responsible for a great number of deaths. The conventional methods of treatment, chemotherapy and radiotherapy, are not always efficient, and multiple side effects are intrinsic for these therapies. In early 70’s appeared a new method called “Photodynamic Therapy" (PDT), that shows few side effects as compared with conventional therapies. The main idea of PDT is to introduce a fotoactive compound into the organism and then irradiate with visible light the site to be treated, producing the active form of the compound that induces the death of cancers cells. The compounds used for this purpose have some disadvantages in their application, which stimulates the search for best compounds. In this work were studied several cyanine dyes with two interacting chromophores (BCD), which seem advantageous for use in PDT. The aim is to study spectral and energetic features of BCD in the presence of DNA, and at various ionic strengths, to suggest their use in cancer photochemotherapy. Four BCD studied in this work were characterized by different angles between chromophores. The experimental analysis was made using various spectroscopic methods such as optical absorption, fluorescence and circular dichroism, and the theoretical treatment was based on computational programs both conventional and created in this work. The results show that BCD has high affinity with DNA molecules, forming various species thus changing the BCD excited state features. The presence of ions modifies the characteristics of dyes and their interaction with DNA. Analyzing the results we can conclude that the characteristics of BCD are promising for their application in PDT, and this makes reasonable future studies of the interaction of these dyes with natural systems such as cells culture and tumors in laboratory animals.
404

Estudo de transferência de energia eletrônica entre poli(p-fenilenovinileno) e corantes iônicos em solução / Study of electronic energy transfer between poly(p-phenylene vinylene) and ionic dyes in solution

Santos, Willy Glen 26 September 2007 (has links)
Neste trabalho estudou-se a síntese fotoquímica do Poli(pfenilenovinileno) (PPV) e a transferência de energia deste polímero para corantes iônicos tais como Basic Blue 3 (BB), Safranina-O (Sf), Eosina-Y (Eoy) e Resazurina (Rz). Na síntese do precursor do PPV, observou-se que o prolongamento do tempo de adição de NaOH no processo de polimerização resultou na inibição do mecanismo SN1, evitando a propagação dos polímeros hidrolisados. Medidas de FTIR e emissão de fluorescência mostraram que o processo de conversão do PTHT em PPV por via fotoquímica também gera polímeros oxidados, assim como na conversão térmica. Espectros de absorção eletrônica do polímero-corante aniônico mostraram que as bandas do corante estão deslocadas para regiões de menor energia, sugerindo a formação de um complexo no estado fundamental. No caso do polímero-corante catiônico, nenhuma mudança espectral é observada, indicando que o efeito de supressão pode estar ocorrendo no estado excitado. Os espectros de fluorescência estacionária e resolvida no tempo indicaram que a transferência de energia ocorre do estado excitado do polímero para o estado fundamental do corante via mecanismo de Förster. No caso do sistema polímero-corante aniônico, a transferência de energia ocorre no estado fundamental das espécies. A constante de supressão dinâmica do sistema PPV-BB foi determinada e comparada com a constante de supressão estática, demonstrando que a supressão do PPV pelo corante não ocorre apenas pelo mecanismo do tipo Förster, mas também pela supressão estática. / The aim of this work was to study the photochemical synthesis of poly(pphenylene vinylene) (PPV) and the energy transfer process evolving PPV and ionic dyes, such as Basic Blue-3, Resazurin, Eosin-Y, Safranin. It was observed that, in the synthesis of PPV precursor, the addition of NaOH in lager time intervals resulted in the inhibition of SN1 mechanism, avoiding the propagation of hydrolyzed polymers. FTIR and fluorescence emission measurements showed that the photochemical conversion from PTHT to PPV also generated oxidized polymers, as in thermal conversion. Electronic absorption of the system polymer-anionic dye revealed a red shift, suggesting the presence of complex species in the ground state. No structural changes or shifts were observed in the system polymer-cationic dye. Steady-state and time resolved fluorescence revealed that energy transfer occurs from the polymer excited-state to dye ground state, by Förster mechanism. For polymeranionic dye system, energy transfer occurs in ground state of both species. Dynamic quenching constant of PPV-Basic Blue-3 was determinated and compared with the static quenching constant. In this case, the quenching of fluorescence occurs by Förster energy transfer and also static quenching.
405

"Efeito de fotoativadores utilizados na irradiação laser intracanal" / Effects of the photosensitizers used during the intracanal laser irradiation.

Gonçalves, Leonardo 13 April 2005 (has links)
Este estudo teve como objetivo avaliar o grau de manchamento dental, ap¨®s o tratamento endodôntico, quando aplicada a terapia fotodinâmica, utilizando-se os corantes azuis de metileno e de orto toluidina como fotossensibilizadores, atrav¨¦s do sistema RGB e K de cores do programa Adobe Photoshop. Vinte dentes humanos unirradiculares tiveram seus canais preparados pela t¨¦cnica seriada com instrumentos endodônticos, Endo-PTC e liquido de Dakin. Constitu¨ªram-se tr¨ºs grupos experimentais, Grupo C: Corante em sua forma liquida, Grupo E: Substância qu¨ªmica Endo PTC associada ao corante em sua formulação e Grupo C+E: Corante em sua forma liquida com irrigação final de liquido de Dakin em conjunto com Endo PTC por 15 min. A leitura de cor foi executada antes (L0), imediatamente ap¨®s o preparo qu¨ªmico-cirurgico (L1) e dez dias depois da irradiação (L2). Analise estat¨ªstica pelo teste de Wilcoxon comprovou que os resultados dos esp¨¦cimes do Grupo E nas interações L1-L2 e L0-L2 não acarretaram diferenças significativas. Pelos resultados obtidos foi poss¨ªvel concluir que: com base no projeto experimental que executou a t¨¦cnica endodôntica tradicional, todos os corantes ativadores testados, alteraram os valores de K. Na an¨¢lise comprobat¨®ria dos resultados de alteração crom¨¢tica pelos valores de K os melhores resultados foram observados nos esp¨¦cimes dos grupos Metileno E e Toluidina E que na interação L0-L1 não apresentaram diferenças estatisticamente significantes a 5%. / The present study had as objective to evaluate the dental staining after the root canal treatment when it¡¯s used the photodynamic therapy, using the dies methylene blue and orto toluidina blue as photosensitizers, through the RGB and K color system from the software Adobe Photoshop. Twenty human single root teeth had its roots canals prepared by the seriated technique using the endodontic instruments plus Endo-PTC and Dakin. Three experimental groups were formed: Group C: dye in its liquid form; Group E: dye associated to the Endo-PTC cream and Group CE: dye in its liquid form with final irrigation of the Dakin plus Endo¨CPTC for 15 minutes. The color measure was taken before (L0), immediately after (L1) and ten days after the laser irradiation. The statistical analysis performed using the Wilcoxon text proves that the results of the specimens of the E Group on the interactions L1-L2 and L0-L2 didn¡¯t have any significant differences. Based on the results obtained it was possible to conclude that: based on the experimental design that performed the traditional endodontic technique, all the activating dyes tested altered the values of K. After carrying out an analysis of the chromatic alteration results according to K values, the best results were observed in specimens of group methylene E and group toluidine E, both of which presented no statistically significant difference for the interaction L0-L1 (p ¡Ü 5%).
406

Expressão de enzimas de Pleurotus spp. e descoloração do corante azul índigo / Enzymes expression by Pleurotus spp. and discoloration of indigo blue dye

Silva, Gilda Mariano 18 December 2014 (has links)
A vinhaça, o bagaço de cana e corantes têxteis descartados são resíduos econômica e ambientalmente importantes. As enzimas inespecíficas e a capacidade adsortiva dos fungos do gênero Pleurotus e do substrato exaurido da produção de cogumelos (SMS) os destacam na biorremediação. O objetivo deste trabalho é avaliar a produção de ligninases por P. sajor-caju e P. ostreatus em fermentação submersa (SmF) e em fermentação sólida (SSF) e aplicar estas na descoloração e detoxificação da vinhaça e do corante azul índigo. Na SmF, as espécies foram crescidas em vinhaça diluída a 50%, livres ou aderidas (\"bio ball\"). A biomassa e atividade das enzimas lacase, peroxidase e MnP foram medidas. Avaliou-se a descoloração da vinhaça tratada e sua toxicidade (D. similis, 48 h). No primeiro experimento de SSF, as espécies cresceram em bagaço+vinhaça. Examinou-se a produção de lacase e MnP e a descoloração de uma solução de azul índigo (pH 4,5) pelo sobrenadante e em contato com o bagaço inoculado. No segundo experimento, avaliou-se as enzimas lacase, peroxidase e MnP dos SMS 1 e 2 (P. ostreatus) em água destilada, tampão citrato-fosfato (pH 5) e solução de Ringer e a descoloração da mesma solução de corante pelos substratos, irradiados ou não. Caracterizou-se o material irradiado, com e sem corante (FTIR) e determinou-se a toxicidade do índigo (H. attenuata, 96 h). Em 12 dias de SmF, a biomassa das duas espécies, nos dois tratamentos, foi equivalente. P. ostreatus com bio ball exibiu maiores atividades de lacase e MnP em seis dias e de peroxidase e MnP em 12, sendo a ultima semelhante à atividade por P. ostreatus livre. P. sajor-caju aderido teve, aos 12 dias, a maior atividade de lacase. Em todos os ensaios, P. sajor-caju descoloriu mais a vinhaça. A vinhaça tratada se tornou menos tóxica para D. similis. Ao 14° dia de crescimento em bagaço, não detectou-se atividade da MnP e a lacase de P. sajor-caju foi maior do a de P. ostreatus: 14 e 0,4 UI g-1, respectivamente. O azul índigo foi melhor descolorido pelo sobrenadante de P. sajor-caju do que por P. ostreatus; a descoloração com bagaço inoculado foi igual para ambos. Para o SMS, a atividade enzimática foi semelhante em todas as extrações. A lacase se destacou no SMS 1, atingindo 2 UI g-1 com 0,1 g mL-1 de água destilada. Com 2,5 g deste substrato, a descoloração de 20 e 60 mL da solução de índigo foi maior com o material não irradiado do que com o irradiado. Para o SMS 2, essa diferença ocorreu apenas com 60 mL. A análise por FTIR revelou a presença de grupos de ligação com o corante. O espectro do SMS 2 diferiu do material controle (sem corante), sugerindo uma maior interação do que no SMS 1. O corante tratado pelo SMS se tornou muito mais tóxico para H. attenuata. Concluiu-se que os resíduos propiciaram a expressão enzimática em P. sajor-caju e P. ostreatus, a descoloração da vinhaça e do azul índigo e a redução de toxicidade da vinhaça. / Sugarcane bagasse and vinasse, as well as discharged textile dyes, are economically and environmentally important wastes. Pleurotus fungi and their spent mushroom waste (SMS) are noticed for their biosorption capacity and for producing unspecific enzymes. The aim of this work is: a) assess ligninases production by P. sajor-caju and P. ostreatus under submerged fermentation (SmF) and solid state fermentation (SSF); b) perform the discoloration and evaluate the detoxification of vinasse and indigo blue dye by those enzymes. Under SmF, the fungi were grown in vinasse 50% with or without a carrier (bio ball). Biomass and laccase, peroxidase and MnP activities were measured, as well as vinasse discoloration and its toxicity (D. similis, 48 h). At the first SSF experiment, the species were inoculated on bagasse+vinasse and laccase and MnP activities were measured; the discoloration of the indigo blue solution was performer with both the enzymatic broth and the inoculated bagasse. The second SSF experiment regarded two SMS from P. ostreatus (SMS 1 and 2). Laccase, peroxidade and MnP activities were measured after extraction with distilled water, phosphate-citrate buffer (pH 5) and Ringer solution. The discoloration of the same indigo solution (irradiated or not materials), followed by FTIR analysis of the irradiated substrate, were performed. The toxicity of treated and untreated indigo blue was given by H. attenuata (96 h). After 12 days under SmF, both species, grown free or with the carrier, produced the same biomass amount. Immobilized P. ostreatus gave the best results for laccase and MnP (six days), MnP (12 days), along with free P. ostreatus, and peroxidase (12 days). Peroxidase (six days) was better produced by free P. ostreatus; laccase (12 days) was higher for immobilized P. sajor-caju. Vinasse was more extensively discolored by P. sajor-caju in all treatments. Treated vinasse became less toxic for D. similis. After 14 days growing on bagasse, both species produced laccase (14 UI g-1 for P. sajor-caju and 0,4 for P. ostreatus) and no MnP activity was observed. Indigo blue was better discolored by P. sajor-caju enzymatic broth (74% at the proportion of 2:8); the discoloration with inoculated bagasse was statistically the same for both fungi. Regarding the SMS, laccase was the outstanding enzyme for SMS 1, reaching 2 UI g-1 with distilled water 0,1 g mL-1. Non irradiated SMS performed a better discoloration of the indigo dye solution than irradiated SMS 1 with 20 and 60 mL of solution. For SMS 2, a greater discoloration by the non-irradiated material compared to the irradiated one was achieved only with 60 mL of the indigo blue solution. SMS 2 + indigo blue spectra was different than the control material (no dye), suggesting that SMS 2 interacted more with the dye than SMS 1. The indigo blue solution had its toxicity towards H. attenuata increased after interacting with SMS 1 and 2. This work concluded that the studied wastes allowed enzymes expression by P. sajor-caju and by P. ostreatus, the discoloration of vinasse and indigo blue and a decrease in vinasse toxicity.
407

Desenvolvimento de célula solar fotoeletroquímica com TiO2 sensibilizado por corantes / Development of photoelectrochemical solar cell with dye-sensitized TiO2

Garcia, Christian Graziani 23 December 2002 (has links)
O trabalho apresenta o desenvolvimento de células solares fotoeletroquímicas baseadas na sensibilização de n-TiO2 por corantes sintéticos e naturais. Abrange as etapas envolvidas na sua obtenção, desde a preparação dos compostos sensibilizadores, filmes semicondutores e meio eletrolítico, até a montagem e medidas de eficiência, com a otimização dos diversos componentes do sistema, num arranjo do tipo sanduíche. O fotoanodo consiste num filme de TiO2 nanocristalino sensibilizado pelo corante num substrato condutor. O contraeletrodo é composto de um substrato condutor recoberto com camada transparente de platina. Entre os eletrodos é disposta a camada de eletrólito, geralmente solução de l2/Lil em acetonitrila. A espessura do filme de semicondutor é controlada com os métodos empregados na deposição de sua dispersão. A transparência final depende ainda do método de preparação das dispersões. Utilizando as espécies cis-[(dcbH2)2RuLL\')2+, dcbH2 = 4,4\'-(CO2H)2-2,2\'bipiridina e L/L\' = cianopiridina, quinolina e H2O, como sensibilizador, obteve-se conversão eficiente de luz visível em eletricidade com valores de IPCE de até 50 % entre 400 e 550 nm. Os processos de transferência e recombinação de elétron na interface sensibilizador/semicondutor foram investigados por experimentos com técnicas resolvidas no tempo empregando sensibilizadores ancorados aos filmes transparentes de TiO2. O trabalho envolveu ainda incorporações técnicas para aumentar a eficiência da célula, como filamentos metálicos protegidos e a combinação de unidades independentes numa associação modular, que são objetos de patentes depositadas. / This work presents the development on photoelectrochemical solar cells based on sensitization of n-TiO2 by synthetic and natural dyes. It comprises several steps involved in the fabrication and assembling of the cells in a sandwich-type design. Preparation of sensitizers, semiconductor films and electrolyte media, as well as efficiency measurements and optimization of several components are presented. The photoanode consists of a dye-sensitized nanocrystalline n-TiO2 film onto a conductive substrate. The counterelectrode is a conductive substrate covered with a thin, transparent platinum layer. The electrolyte layer, usually l2/Lil in acetonitrile, is placed between the electrodes. The deposition process of the semiconductor dispersion onto the substrates regulates the resulting thickness of the film. The final transparency is also controlled by the procedure employed in the preparation of the semiconductor dispersion. The species cis-[(dcbH2)2RuLL\']2+, dcbH2 = 4,4\'-(CO2H)2-2,2\'-bipyridine and L/L\' = 4-cyanopyridine, quinoline and H2O, were employed as sensitizers resulting in IPCE (Incident Monochromatic Photon to Current Conversion Efficiency) values as high as 50 % from 400 to 550 nm. Electron transfer and recombination processes across the semiconductor/sensitizer interface were investigated with time-resolved experiments employing transparent films of n-TiO2 sensitized by the anchored species. Other approaches aiming improvements in efficiencies and the preparation of photoelectrochemical solar cells for different applications or through environmentally friendly processes are discussed. The use of protected metallic filaments and the modular arrangement of single cells are issues of patents.
408

A química do ranelato: aspectos fundamentais da estrutura eletrônica e reatividade / Ranelate chemistry: fundamental aspects of electronic structure and reactivity

Rocha, Julio Cesar da 11 October 2018 (has links)
O ranelato de estrôncio é uma droga encontrada nas farmácias com o nome de Protos®, sendo bastante consumida na forma de chás para o tratamento da osteosporose, uma patologia do tecido ósseo ligada ao metabolismo de reabsorção óssea e a produção de osteoblastos (células precursoras da matriz óssea). Sua estrutura inusitada apresenta um anel tiofeno com quatro grupos carboxílicos e um grupo nitrila, lembrando o complexante clássico EDTA. Essa semelhança inspirou o desenvolvimento desta tese, visando entender a química do íon ranelato na presença do estrôncio e outros íons metálicos, e dessa forma, obter indícios de como pode atuar ao nível molecular no organismo. Com esse objetivo, a molécula foi criteriosamente estudada baseada em espectroscopia (RMN, FTIR, Raman, EDX e Vis-UV), difração de raiosX de pó, espectrometria de massa, e modelagem molecular (MM+, ZINDO/S, DFT, TD-DFT). Ao longo do trabalho, observou-se que em meio ácido, sob exposição direta ao sol ou irradiação UV, havia a formação de uma coloração azul intensa, chamando a atenção para uma nova espécie, ainda não reportada na literatura. Esse produto mostrou ser bastante estável, particularmente sob luz solar, contrastando com a maioria dos corantes orgânicos convencionais. Os espectros de RMN e de massa indicaram a formação de um novo corante bistiofeno, envolvendo o desprendimento fotoquímico de CO2 via descarboxilação do grupo ligado ao carbono 5 do anel, seguido pela dimerização. Por outro lado, na presença de íons de ouro(III), o ranelato reage rapidamente produzindo suspensões vermelhas de nanopartículas de ouro, que permanecem estáveis por longo tempo, especialmente no caso dos sais de sódio e lítio. As reações ocorrem espontaneamente à temperatura ambiente, e a cinética foi investigada espectrofotometricamente variando a proporção ouro/ranelato (em mol) de 8:1 a 1:8. As partículas formadas foram monitoradas por microscopia eletrônica de transmissão de alta resolução. Por analogia com o método de Turkevich, a reação parece envolver a oxidação do íon ranelato por AuIII, produzindo compostos com AuI e convertendo o grupo carboxilato em CO2. É possível que o AuI permaneça ligado covalentemente ao anel tiofeno, coordenando-se pelo átomo de carbono 5. Nessa forma, o composto pode iniciar a nucleação das nanopartículas por meio de reações redox sucessivas com as espécies AuIII existentes, e desproporcionamento de AuI em Au0 e AuIII. Em condições próximas da equimolar são formadas partículas esféricas, enquanto que com excesso de AuIII, partículas anisotrópicas foram observadas. No presente estágio, a química do íon ranelato ainda é muito incipiente, mas já é possível vislumbrar sua exploração em diversas áreas da química, indústria de corantes além de novas aplicações medicinais. / Strontium ranelate is a drug commercially available in Brazil as Protos®. It is widely consumed as tea infusions for the treatment of osteosporosis, a disease of the bone tissues related to the bone resorption and osteoblast replication. Its peculiar structure is composed by a central thiophene ring, exhibiting four carboxylate groups and a nitrile moiety, resembling the classical metal chelating agent EDTA. Such analogy inspired the present thesis, aiming the understanding of its chemistry in the presence of metal ions such as lithium, sodium and strontium, and expecting to provide some clues for its action in the organism. In this way, the molecule was extensively studied based on spectroscopy (NMR, FTIR, Raman, EDX and VisUV), powder X-ray diffraction, mass spectrometry, and molecular modeling methods (MM+, ZINDO/S, DFT and TD-DFT). In acidic solution, under direct solar or UV irradiation, a deep blue color was observed, calling our attention for its conversion into a new species not yet reported in the literature. This product was remarkably stable, particularly to sun light, in contrast to most conventional dyes. Our research based on NMR and mass spectra indicated the formation of a new bisthiophene dye, by the photochemical release of the carboxylate group bound at the C5 atom of the ring, followed by dimerization. On the other hand, in the presence of gold(III) ions, ranelate reacts rapidly yielding red nanoparticle suspensions which remain stable in the case of its sodium and lithium salts, but turning into blue and precipitating in the case of the strontium species. The reactions proceed spontaneously at room temperature and the kinetics were investigated spectrophotometrically by varying the ranelate/gold molar ratio from 8:1 to 1:8, and monitoring the generated nanoparticles by HRTEM. By analogy with the citrate method developed by Turkevich, the reaction seems to involve the oxidation of the ranelate ion by AuIII, yielding AuI species and converting carboxylate group into CO2. Presumably, the AuI ion remains covalently attached to the thiophene ring by coordinating to the C5 atom. In this way it can act as a nucleation center for the formation of nanoparticles by means of successive redox and disproportionation reactions with the remaining AuIII species. Under nearly equimolar conditions, spherical nanoparticles are preferentially formed. At high AuIII concentrations, formation of anisotropic gold nanoparticles is observed. The chemistry of the ranelate ions is yet at very beginning, but exciting perspectives can already be seen in chemistry, medicine and in dyes industry.
409

Price reduction or "service package"?: a study of alternative marketing strategies.

January 1989 (has links)
by Chu Kwong-young. / Thesis (M.B.A.)--Chinese University of Hong Kong, 1989. / Bibliography: leaves 94-96.
410

Enhancement of chemical degradation of synthetic dyes by biosorption.

January 1998 (has links)
by Stephen, Man-yuen Cheng. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 124-141). / Abstract also in Chinese. / Acknowledgements --- p.i / Abstract --- p.ii / List of Figures --- p.iv / List of Tables --- p.ix / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- The development of dyes --- p.1 / Chapter 1.2 --- The chemistry of azo dyes --- p.2 / Chapter 1.3 --- "Evaluation of dyes submitted under the ""Toxic Substances Control Act"" new chemicals programme" --- p.6 / Chapter 1.4 --- Environmental concerns of dyes --- p.7 / Chapter 1.5 --- Decolorization techniques --- p.11 / Chapter 1.5.1 --- Activated sludge process --- p.11 / Chapter 1.5.2 --- Chlorination --- p.12 / Chapter 1.5.3 --- Fenton's reaction --- p.13 / Chapter 1.5.4 --- Ozonation --- p.13 / Chapter 1.5.5 --- Adsorption by activated carbon --- p.13 / Chapter 1.5.6 --- Chemical flocculation --- p.14 / Chapter 1.5.7 --- Coagulation --- p.14 / Chapter 1.5.8 --- Advance Oxidation Process --- p.15 / Chapter 1.5.8a --- Photocatalytic activation --- p.17 / Chapter 1.5.8b --- Enhancement of reaction rates of photocatalytic reaction --- p.21 / Chapter 1.5.9 --- Biosorption of azo dyes by Pseudomonas sp. K-l --- p.23 / Chapter 1.6 --- Water pollution in Hong Kong --- p.24 / Chapter 1.7 --- Purpose of study --- p.24 / Chapter 2 --- Objectives --- p.27 / Chapter 3 --- Materials and Methods --- p.28 / Chapter 3.1 --- Materials --- p.28 / Chapter 3.1.1 --- Azo dyes --- p.28 / Chapter 3.1.2 --- Biosorbent --- p.28 / Chapter 3.1.3 --- Chemicals --- p.28 / Chapter 3.2 --- Photocatalytic reactor --- p.31 / Chapter 3.3 --- Determination of the peak absorbance of five azo dyes at different pH --- p.31 / Chapter 3.4 --- Determination of dye concentration by measuring at peak absorbance --- p.37 / Chapter 3.5 --- Determination of pseudo-first-order rate constant --- p.37 / Chapter 3.6 --- Effect of initial concentration of procion red MX-5B on photocatalytic degradation --- p.39 / Chapter 3.7 --- Effect of initial concentration of hydrogen peroxide on photocatalytic degradation of procion red MX-5B --- p.40 / Chapter 3.8 --- Effect of initial pH on the photocatalytic degradation of procion red MX-5B --- p.40 / Chapter 3.9 --- Effect of initial temperature on the photocatalytic degradation of procion red MX-5B --- p.40 / Chapter 3.10 --- Effect of titanium dioxide on the photocatalytic degradation of procion red MX-5B --- p.40 / Chapter 3.11 --- Effect of UV intensity in the photocatalytic degradation of procion red MX-5B --- p.41 / Chapter 3.12 --- Degradation kinetics of different dyes --- p.41 / Chapter 3.13 --- Degradation of 40 mg/L of procion red MX-5B under optimized conditions --- p.41 / Chapter 3.14 --- "Degradation of 1,000 mg/L of procion red MX-5B under optimized conditions" --- p.42 / Chapter 3.15 --- Temporal change of the concentration of procion red MX-5B in calcium alginate beads --- p.42 / Chapter 3.16 --- "Temporal change of the concentration of procion red MX-5B in alginate beads of 5,000 mg/L of Ti02" --- p.43 / Chapter 3.17 --- "Temporal change of the concentration of procion red MX-5B in alginate beads of 10,000 mg/L of Ti02" --- p.43 / Chapter 3.18 --- Effect of the concentration of titanium dioxide in alginate beads in the photocatalytic degradation of procion red MX-5B --- p.45 / Chapter 3.19 --- "Effect of hydrogen peroxide in the photocatalytic degradation of procion red MX-5B in 5,000 mg/L of Ti02-alginate beads" --- p.47 / Chapter 3.20 --- "Temporal change of the concentration of procion red MX-5B in alginate beads with 5,000 mg/L of Ti02" --- p.47 / Chapter 3.21 --- "Effect of biomass of Pseudomonas sp. K1 on the photocatalytic degradation of procion red MX-5B in alginate beads with 5,000 mg/L of Ti02" --- p.48 / Chapter 3.22 --- Diffuse reflectance-IR spectroscopic analysis of degradation product(s) --- p.49 / Chapter 3.23 --- Nuclear magnetic resonance (NMR) spectroscopic analysis of degradation products --- p.49 / Chapter 3.24 --- Toxicological evaluation of degradation products using Microtox® test --- p.51 / Chapter 4 --- Result --- p.54 / Chapter 4.1 --- Biosorption of dyes by Pseudomonas sp. K1 --- p.54 / Chapter 4.2 --- UV intensities of the eight Cole-Parmer UV lamps at 365 nm --- p.54 / Chapter 4.3 --- Determination of the peak absorbance of five azo dyes at different pH using scanning spectrophotometer --- p.54 / Chapter 4.4 --- Determination of dye concentration by measuring at peak absorbance --- p.66 / Chapter 4.5 --- Effect of initial concentration of procion red MX-5Bin photocatalytic degradation rate --- p.66 / Chapter 4.6 --- Effect of initial concentration of hydrogen peroxide on the photocatalytic degradation of procion red MX-5B --- p.73 / Chapter 4.7 --- Effect of initial pH on photocatalytic degradation of procion red MX-5B --- p.73 / Chapter 4.8 --- Effect of initial temperature on photocatalytic degradation of procion red MX-5B --- p.73 / Chapter 4.9 --- Effect of titanium dioxide on photocatalytic degradation of procion red MX-5B --- p.77 / Chapter 4.10 --- Effect of UV intensity on photocatalytic degradation of procion red MX-5B --- p.77 / Chapter 4.11 --- Photocatalytic degradation kinetics of different azo dyes --- p.77 / Chapter 4.12 --- Photocatalytic degradation of 40 mg/L of reactive red241 under optimized conditions --- p.77 / Chapter 4.13 --- Photocatalytic degradation of 40 mg/L procion red MX-5B under optimized conditions --- p.81 / Chapter 4.14 --- "Photocatalytic degradation of 1,000 mg/L of procion red MX-5B under optimized conditions" --- p.81 / Chapter 4.15 --- Temporal change of the concentration of procion red MX-5B in calcium alginate beads --- p.81 / Chapter 4.16 --- "Temporal changes of the concentration of procion red MX-5B in 5,000 mg/L of Ti02-alginate beads" --- p.85 / Chapter 4.17 --- "Temporal change of the concentration of procion red MX-5B in 10,000 mg/L of Ti02-alginate beads" --- p.85 / Chapter 4.18 --- Effect of the concentration of titanium dioxide in alginate beads in the photocatalytic degradation of procion red MX-5B --- p.89 / Chapter 4.19 --- "Effect of hydrogen peroxide in the photocatalytic degradation of procion red MX-5B in 5,000 mg/L of Ti02-alginate beads" --- p.89 / Chapter 4.20 --- "Temporal change of the concentration of procion red MX-5Bin alginate beads with 5,000 mg/L of Ti02" --- p.89 / Chapter 4.21 --- "Effect ofbiomass of Pseudomonas sp. K1 on the photocatalytic degradation of procion red MX-5B in 5,000 mg/L of Ti02-alginate beads" --- p.93 / Chapter 4.22 --- Degradation products analysis using diffuse reflectance-IR spectroscopy --- p.93 / Chapter 4.23 --- Degradation products analysis using nuclear magnetic resonance (NMR) --- p.101 / Chapter 4.24 --- Toxicological evaluation of degradation products using Microtox® test --- p.101 / Chapter 5 --- Discussion --- p.104 / Chapter 5.1 --- Biosorption of azo dyes in Pseudomonas sp. K-l --- p.104 / Chapter 5.2 --- Optimization of photocatalytic degradation of azo dyes --- p.105 / Chapter 5.2.1 --- Effect of initial concentration of procion red MX-5B on the photocatalytic degradation --- p.105 / Chapter 5.2.2 --- Effect of initial concentration of hydrogen peroxide on the photocatalytic degradation --- p.106 / Chapter 5.2.3 --- Effect of initial pH on the photocatalytic degradation --- p.107 / Chapter 5.2.4 --- Effect of initial temperature on the photocatalytic degradation --- p.108 / Chapter 5.2.5 --- Effect of titanium dioxide on the photocatalytic degradation --- p.109 / Chapter 5.2.6 --- Effect of UV intensity on the photocatalytic degradation --- p.110 / Chapter 5.2.7 --- Degradation kinetics of different dyes --- p.111 / Chapter 5.2.8 --- Optimized conditions for PCO of reactive red 241 and procion red --- p.112 / Chapter 5.3 --- Immobilization of titanium dioxide and Pseudomonas sp. K-l in alginate beads --- p.113 / Chapter 5.3.1 --- Temporal changes of the concentration of dye in alginate beads --- p.113 / Chapter 5.3.2 --- Effect of titanium dioxide in alginate beads in PCO --- p.114 / Chapter 5.3.3 --- Effect of hydrogen peroxide in alginate beads in PCO --- p.115 / Chapter 5.3.4 --- "Temporal change of dye concentration in alginate beads of 5,000 mg/L" --- p.115 / Chapter 5.3.5 --- Effect of biomass of Pseudomonas sp. K-l in alginate beads on the PCO of dye --- p.115 / Chapter 5.4 --- Diffuse reflectance IR spectroscopic analysis of degradation products --- p.116 / Chapter 5.5 --- 1HNMR analysis of degradation products --- p.119 / Chapter 5.6 --- Toxicological evaluation of degradation products using Microtox® test --- p.120 / Chapter 5.7 --- Application --- p.121 / Chapter 6 --- Conclusion --- p.122 / Chapter 7 --- References --- p.124 / Appendix 1 --- p.142 / Appendix 2 --- p.143

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