• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 29
  • 27
  • 9
  • 4
  • 3
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 83
  • 23
  • 20
  • 14
  • 12
  • 11
  • 10
  • 9
  • 8
  • 8
  • 7
  • 7
  • 7
  • 7
  • 6
  • 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.
41

A eletrocoagulação na terapêutica das lesões intra-epiteliais escamosas de alto grau do colo uterino /

Lian, Ie Tjie. January 2001 (has links)
Orientador: Paulo Traiman / Resumo: Analisar a eficácia da eletrocoagulação, como terapêutica nas pacientes portadoras de lesão intra-epitelial escamosa de alto grau de colo uterino. Pacientes e métodos: Estudaram-se prospectivamente 116 pacientes portadoras de lesão intra-epitelial escamosa de alto grau do colo de útero, distribuídas aleatoriamente, com 49 pacientes no grupo de estudo e 67 pacientes no grupo controle. Ambos os grupos foram avaliados quanto à idade, coitarca, paridade, hábito de tabagismo, número de parceiros sexuais, uso de drogas, presença ou antecedente de lesão condilomatosa vulvar, raça e escolaridade. Essas variáveis apresentaram-se homogêneas em ambos os grupos. Todas as pacientes do grupo de estudo e do grupo-controle foram submetidas a colposcopia... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Analyzing the efficiency of electrocoagulation as therapeutics in patients carrying high degree squamous intraepithelial lesion of the uterine cervix. Patients and methods: 116 patients carrying high risk intraepithelial lesion of the uterine cervix were prospectively studied, randomly distributed, being 49 patients in the study-group and 67 patients in the control-group. Both groups were evaluated according to age, first copulation, parity, smoking habits, number of sex partners, drug usage, presence or previous condylomatous lesion of the vulva, race and schooling. Such variables were found to be even in both groups. All patients from both groups were submitted to colposcopy, oncological cytology and biopsy of the uterine cervix. The study- group patients were treated with electrocoagulation of the uterine cervix and later submitted to conization after two months. The control-group patients underwent conization only. To assess the significance of the resuts, qui-square and Kappa agreement test were used. Results: In the study-group, electrocoagulation of the uterine cervix caused regression of the lesion in 73,5% of the cases, 20,4% remained unchanged, and there was progression... (Complete abstract click electronic access below) / Mestre
42

Déferrisation des eaux par procédé d’électrocoagulation : étude des phénomènes physico-chimiques et réactionnels impliqués / Iron removal from water by electrocoagulation : investigation of the physico-chemical and reaction phenomena involved

Doggaz, Amira 11 October 2018 (has links)
La demande croissante en eau nécessite l’exploitation de certaines sources ferrugineuses. Cependant la présence du Fe(II) dissous induit des problèmes d’ordre esthétique et organoleptique. L’électrocoagulation (EC), en tant que procédé substitut de la méthode conventionnelle, a prouvé son efficacité pour l’élimination du fer. En revanche, le mécanisme de déferrisation par EC reste peu connu et non maitrisé. La difficulté de l’étudier provient de l’intervention simultanée de plusieurs phénomènes. Les travaux de cette thèse ont de ce fait pour objectif d’apporter une meilleure compréhension du mécanisme d’élimination du Fe(II) par EC. Ainsi, différentes méthodes d’élimination du fer et des techniques d’analyses du liquide et du solide ont été exploitées. Au moyen d’une unité à recirculation forcée de la solution avec des électrodes en aluminium, la technique d’EC parvient à éliminer 97% d’une solution de 25 mg/L du fer. La quantité optimale d’énergie est de 0,21 kWh/m3. Des essais en milieu anoxique ont montré que la réduction du fer ionique par adsorption sur les flocs de Al(OH)3 est faible (18%). Par oxydation-précipitation à pH 6,5, le Al(OH)3 catalyse la réaction d’oxydation. Cet effet est plus prononcé en présence des ions chlorure qu’en ions sulfate. La spéciation associée à la modélisation cinétique ont permis d’apporter des explications sur le mode d’action de ces ions. Cependant, les expériences par EC en milieux anoxique et oxygéné montrent que la part de l’oxydation dans l’élimination du fer est négligeable pour les pH de travail. Les calculs thermodynamiques au voisinage des électrodes permettent de proposer la précipitation de Fe(OH)2, comme mécanisme prédominant d’élimination du fer par EC. La présence des carbonates réduit la performance du système par la réduction de la précipitation de Fe(OH)2 suite à la diminution du pH local et le Fe2+ libre par formation des complexes du Fe(II) / Water scarcity in some areas requires the exploitation of some ferruginous sources. However, the presence of Fe(II) induces aesthetic and organoleptic problems. The electrocoagulation (EC), as an alternative process of the conventional method, proved its efficacy for iron removal. Nevertheless, the iron removal mechanism in EC process remains unstudied and still unclear. The simultaneous involvement of several phenomena makes difficulties to study the system. This thesis aims to provide a better understanding of the mechanism of Fe(II) removal by EC and to highlight the phenomena that are most likely. Thus, different methods of iron removal and liquid and solid analysis techniques have been used. By means of a forced recirculating unit, EC's technique with aluminum electrodes reduce the dissolved iron of 25 mg Fe(II)/L - solution by about 97% with an optimum energy amount of 0,21 kWh/m3. Anoxic experiments showed that the reduction of ionic iron by adsorption on Al(OH)3 flocs is negligible (18%). Oxidation-precipitation experiments showed that at work pH 6,5, Al(OH)3 catalyzes the oxidation reaction. The catalytic effect is more pronounced in the presence of chloride ions than in sulfate ions. Fe(II)-speciation associated with kinetic modeling have allowed to explain of the mode by which these ions acts on the oxidation reaction kinetics. However, EC experiments in anoxic and oxygenated media show that the proportion of oxidation in iron removal is insignificant for work pH. Thermodynamic calculations allowed to propose the precipitation of Fe(OH)2 in the vicinity of the cathode as the predominant mechanism of iron removal by EC. The presence of carbonates affects the performance of the process by reducing the precipitation of Fe(OH)2; this was attributed to the decrease of the local pH and the free Fe(II) amount by Fe(II)-complexes formation
43

A eletrocoagulação na terapêutica das lesões intra-epiteliais escamosas de alto grau do colo uterino

Lian, Ie Tjie [UNESP] January 2001 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:26:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2001Bitstream added on 2014-06-13T19:13:28Z : No. of bitstreams: 1 lian_it_me_botfm.pdf: 1463220 bytes, checksum: eb4ee40b710b15dce35aeb229f8308a2 (MD5) / Analisar a eficácia da eletrocoagulação, como terapêutica nas pacientes portadoras de lesão intra-epitelial escamosa de alto grau de colo uterino. Pacientes e métodos: Estudaram-se prospectivamente 116 pacientes portadoras de lesão intra-epitelial escamosa de alto grau do colo de útero, distribuídas aleatoriamente, com 49 pacientes no grupo de estudo e 67 pacientes no grupo controle. Ambos os grupos foram avaliados quanto à idade, coitarca, paridade, hábito de tabagismo, número de parceiros sexuais, uso de drogas, presença ou antecedente de lesão condilomatosa vulvar, raça e escolaridade. Essas variáveis apresentaram-se homogêneas em ambos os grupos. Todas as pacientes do grupo de estudo e do grupo-controle foram submetidas a colposcopia... / Analyzing the efficiency of electrocoagulation as therapeutics in patients carrying high degree squamous intraepithelial lesion of the uterine cervix. Patients and methods: 116 patients carrying high risk intraepithelial lesion of the uterine cervix were prospectively studied, randomly distributed, being 49 patients in the study-group and 67 patients in the control-group. Both groups were evaluated according to age, first copulation, parity, smoking habits, number of sex partners, drug usage, presence or previous condylomatous lesion of the vulva, race and schooling. Such variables were found to be even in both groups. All patients from both groups were submitted to colposcopy, oncological cytology and biopsy of the uterine cervix. The study- group patients were treated with electrocoagulation of the uterine cervix and later submitted to conization after two months. The control-group patients underwent conization only. To assess the significance of the resuts, qui-square and Kappa agreement test were used. Results: In the study-group, electrocoagulation of the uterine cervix caused regression of the lesion in 73,5% of the cases, 20,4% remained unchanged, and there was progression... (Complete abstract click electronic access below)
44

Tratamento de efluentes de tanques de piscicultura aplicando a tecnologia de eletrocoagulaÃÃo / Effluent treatment of fishponds applying technology electrocoagulation

Josà Pedro Varela da Silva 11 October 2013 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Para a realizaÃÃo deste trabalho, foi utilizada a tÃcnica da eletrocoagulaÃÃo (EC) para o tratamento de efluente de piscicultura. Um reator de EC em escala de laboratÃrio, com capacidade de 1,5 L foi montado, utilizando um conjunto de quatro placas de eletrodos de alumÃnio, um agitador mecÃnico de alto torque microprocessado, fios condutores com garras de jacarà e uma fonte de tensÃo com potÃncia regulÃvel. Os eletrodos foram arranjados dentro da cÃlula eletrolÃtica de forma monopolar, em paralelo e a uma distÃncia de 11 mm. O efluente utilizado neste estudo foi coletado em tanques de piscicultura do centro de criaÃÃo de peixes do Departamento de Engenharia de Pesca da Universidade Federal do CearÃ. Para a determinaÃÃo da melhor condiÃÃo de operaÃÃo do reator, foi feito um planejamento experimental por intermÃdio do Software âStatgraficsâ, definindo, as variÃveis operacionais e os seus respetivos intervalos de variaÃÃo (pH inicial de 4 a 8, condutividade de 1000 a 4000 μS cm-1, tempo de eletrolise de 15 a 35 min., agitaÃÃo de 200 a 600 rpm e corrente de 1 a 2,5 A), que combinadas entre si totalizaram um total de 35 ensaios experimentais. Com base nos resultados obtidos por meio das anÃlises fÃsico-quÃmicas em laboratÃrio, pode-se afirmar que o pH inicial=8, condutividade=1000 μS cm-1, tempo=35 min., agitaÃÃo=200 rpm e corrente=2,5 A, sÃo as condiÃÃes Ãtimas de operaÃÃo do reator. Nestas condiÃÃes, alcanÃaram remoÃÃo de 84,95% para DQO, 98,06% para nitrito, 82,43% para nitrato, 98,05% para fÃsforo total e 95,32% para a turbidez, sendo o custo operacional de 4,59 R$/m3 de efluente tratado. Com base nos resultados obtidos, pode-se concluir que alguns dos parÃmetros analisados (pH, turbidez, temperatura, STD, nitrito, nitrato e fÃsforo total) estÃo de acordo com os padrÃes estabelecidos para Ãgua doce, classe 2, pela ResoluÃÃo CONAMA n 357/05, e de acordo com a ResoluÃÃo CONAMA n 430/2011 e a Portaria n 154/2002 da SEMACE (CE), para lanÃamento do efluente final nos corpos receptores. A tÃcnica de eletrocoagulaÃÃo alÃm de ser um mÃtodo alternativo, eficiente e promissor para tratamento de efluentes de piscicultura, tambÃm mostrou ser ecologicamente correto por dispensar o consumo elevado de reagentes,ao contrÃrio do que acontece no tratamento convencional. / For this work, we used the technique of electrocoagulation (EC) for the treatment of effluent from fish farms. An EC reactor at laboratory scale with a capacity of 1,5 L was assembled using a set of four plates of aluminum electrodes, a mechanical stirrer high torque microprocessor, wires with alligator clips and a voltage source with power adjustable. The electrodes were arranged inside of the electrolytic cell in a monopolar form, in parallel and at a distance of 11 mm. The effluent used in this study was collected in fishponds of fish breeding center of the Engineering Department of Fisheries, Federal University of CearÃ. To determine the best operating condition of the reactor, an experimental design was performed using the software "Statgrafics", defining the operational variables and their respective intervals (Initial pH 4 to 8, conductivity from 1000 to 4000 μS cm-1, electrolysis time 15 to 35 min., agitation 200-600 rpm and electrical current from 1 to 2,5 A), that combined together, performing a total of 35 runs. Based on the results obtained by means of physical-chemical analysis in the laboratory, it can be stated that the initial pH=8, conductivity=1000 μS cm-1, time=35 min., agitation=200 rpm and electrical current=2,5 A, are the optimal operating conditions of the reactor. Under these conditions, removal reached 84,95% for COD, 98,06% for nitrite, 82,43% for nitrate, 98,05% for total phosphorus and 95,32% for turbidity, resulting an operating cost of R$ 4,59 per m3 of treated effluent. Based on the results obtained, it can be concluded that some of the analyzed parameters (pH, turbidity, temperature, STD, nitrite, nitrate and total phosphorus) are in accordance with the standards established for fresh water, class 2, by CONAMA Resolution n 357/05, and according to CONAMA Resolution n 430/2011 and Decree n 154/2002 of SEMACE (CE), for release of the final effluent in the receiving water bodies. The technique of electrocoagulation besides being an alternative, efficient and promising for treating effluents from fish farming, also proved to be environmentally friendly for taking the high consumption of reagents, contrary to what happens in conventional treatment.
45

Removal of Cu (II), Ni (II), Cd (II) and Pb (II) of wastewater of electroplating industry using hybrid system adsorption electro-flotation-coagulation / RemoÃÃo de Cu(II), Ni(II), Cd(II) E Pb(II) de efluentes de indÃstrias de galvanoplastia usando o sistema hÃbrido adsorÃÃo-eletro-flotaÃÃo-coagulaÃÃo

Raimundo Nonato Pereira Teixeira 12 February 2015 (has links)
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Bodies of water contamination problems have stimulated many researchers around the world in the search for alternatives to solve or minimize the effects caused by discharges of toxic materials to the environment. What is desired, preferably, is that such solutions are economically viable and efficient. Toxic metals on the list of the main contaminants of water bodies. Because these are very dangerous chemicals, this class of materials has led many research groups seeking to achieve avoid contamination of water bodies by this type of material. The wastewater generated by electroplating industries have a high concentration of metal ions, so it should be treated before discharge to receiving waters. The processes using adsorption emerge as one of the research lines most valued by many researchers in order to contribute to this issue. Electrochemical processes have also been tested in the remediation of wastewater contaminated with various pollutants, including toxic metals. Natural clays play an important role in this type of study. Several studies have shown very promising results with the use of such material in the removal of toxic metals. This paper aims to conduct a comparative study of removal efficiency of Cu (II), Ni (II), Cd (II) and Pb (II) from six natural clays Brazilian soil. The clays were used: sodium Clay (AS), green clay (AV), clay chocolate calcium (ACCA), ferric clay (AF), attapulgite (AT) and kaolin (CAU). Balance studies were performed through adsorption isotherms in batch systems. For the balance of studies used monoelementares systems and multielement containing the four metal ions. We have also performed the kinetic study to evaluate the lower equilibrium times. Finally experiments were conducted with hybrid systems which use electrocoagulation-adsorption and coagulation with the purpose of working in a continuous system. The results show that all clays have good adsorption capacity for the four ions. The adsorption equilibrium results were compared with the Langmuir, Freundlich and Temkin. The maximum adsorption capacity obtained from monoelementares solutions were: 50.76 mg.g-1 [AS / Pb (II)], 50.76 mg.g-1 [AV / Cu (II)], 57.14 mg.g-1 [ACCA / Cu (II)], 34.72 mg.g-1 [AF / Cu (II)], 169.4 mg.g-1 [AT / Pb (II)] and 10 29 mg.g-1 [CAU / Cu (II)]. The kinetic model best suited to the experimental data was the pseudo second order. The Webber-Morri diffusion models and Boyd show that adsorption processes occur in more than one step and that in the early days predominates intrafilme diffusion process. The electrocoagulation-clotting experiments associated with adsorption with clays are promising because it promoted an increase in the removal capacity and facilitate the separation of the clay from the aqueous phase. The ion removal capacities of Cu (II) from industrial wastewater using the hybrid system were: 54% [AL / AS] to 45% [Al / ACCA] to 57% [Al / HF] 33% to [AL / AT], 48% / Problemas de contaminaÃÃo dos corpos hÃdricos tÃm estimulado muitos pesquisadores em todo mundo na busca de alternativas que resolvam ou minimizem os efeitos causados pelos descartes de materiais tÃxicos ao meio ambiente. O que se deseja, preferencialmente, à que tais soluÃÃes sejam economicamente viÃveis e eficientes. Os metais tÃxicos fazem parte da lista dos principais contaminantes dos corpos hÃdricos. Por se tratarem de substÃncias quÃmicas bastante perigosas, esta classe de material tem levado muitos grupos de pesquisa na busca de conseguir evitar a contaminaÃÃo dos corpos hÃdricos por este tipo de material. Os efluentes gerados pelas indÃstrias de galvanoplastia possuem uma elevada concentraÃÃo de Ãons metÃlicos, por isso devem ser tratados antes do descarte aos corpos receptores. Os processos que usam adsorÃÃo despontam como uma das linhas de pesquisas mais avaliadas por inÃmeros pesquisadores no intuito de contribuir com esta problemÃtica. Os processos eletroquÃmicos tambÃm tÃm sido testados na remediaÃÃo de efluentes contaminado por diversos poluentes, inclusive metais tÃxicos. As argilas naturais desempenham um papel importante neste tipo de estudo. Diversos trabalhos vÃm apresentando resultados bastante promissores com o uso deste tipo de material na remoÃÃo de metais tÃxicos. Este trabalho se propÃe a realizar um estudo comparativo de eficiÃncia de remoÃÃo dos Ãons Cu(II), Ni(II), Cd(II) e Pb(II) a partir de seis argilas naturais de solo brasileiro. As argilas utilizadas foram: Argila sÃdica (AS), argila verde (AV), argila chocolate cÃlcica (ACCA), argila fÃrrica (AF), atapulgita (AT) e caulim (CAU). Foram realizados estudos de equilÃbrio atravÃs de isotermas de adsorÃÃo em sistemas de batelada. Para os estudos de equilÃbrio utilizaram-se sistemas monoelementares e multielementares contendo os quatro Ãons metÃlicos. Realizou-se tambÃm o estudo cinÃtico para avaliarmos os menores tempos de equilÃbrio. Por fim foram realizados experimentos com sistemas hÃbridos que utilizam adsorÃÃo e eletroflotaÃÃo-coagulaÃÃo, com a finalidade de trabalharmos em sistemas contÃnuos. Os resultados obtidos mostram que todas as argilas apresentam boa capacidade de adsorÃÃo para os quatro Ãons. Os resultados de equilÃbrio de adsorÃÃo foram confrontados com os modelos de Langmuir, Freundlich e Temkin. As capacidades mÃximas de adsorÃÃo obtidas a partir de soluÃÃes monoelementares foram: 50,76 mg.g-1 [AS/Pb(II)], 50,76 mg.g-1 [AV/Cu(II)], 57,14 mg.g-1 [ACCA/ Cu(II)], 34,72 mg.g-1 [AF/ Cu(II)], 169,4 mg.g-1 [AT/Pb(II)] e 10,29 mg.g-1 [CAU/Cu(II)]. O modelo cinÃtico que melhor se adequou aos dados experimentais foi o de pseudo segunda ordem. Os modelos de difusÃo de Webber-Morri e Boyd demonstram que os processos de adsorÃÃo ocorrem em mais de uma etapa e que nos primeiros tempos predomina o processo de difusÃo intrafilme. Os experimentos de eletroflotaÃÃo-coagulaÃÃo associados à adsorÃÃo com argilas mostraram-se promissores porque promoveram um incremento nas capacidades de remoÃÃo e facilitam a separaÃÃo dos argilominerais da fase aquosa. As capacidades de remoÃÃo do Ãon Cu(II) a partir do efluente industrial usando o sistema hÃbrido foram: 54% para [AL/AS], 45% para [AL/ACCA], 57% para [AL/AF] 33% para [AL/AT], 48% para [FE/AS], 47% para [FE/ACCA], 54% para [FE/AF] e 40% para [FE/AT].
46

Estudo do processo de eletrocoagulaÃÃo/floculaÃÃo aplicado ao polimento de efluente domÃstico / Study of electrocoagulation process / flocculation applied to the wastewater polishing

Liana Geisa Conrado Maia 11 July 2014 (has links)
O presente trabalho propÃs uma alternativa de polimento de efluentes sanitÃrios por meio da tÃcnica deeletrocoagulaÃÃo/floculaÃÃo. O trabalho investigou a aplicaÃÃo desta tecnologia com dois conjuntos de eletrodos, alumÃnio e aÃo carbono,no polimento do efluente da lagoa de estabilizaÃÃo da estaÃÃo de tratamento de efluentes do Conjunto Nova MetrÃpole, localizada na cidade de Caucaia, CearÃ. Os estudos de aplicaÃÃo da tÃcnica para tratamento de efluentes foram feitos em nÃvel de bancada. Com o objetivo de avaliar a viabilidade tÃcnico-econÃmica da implantaÃÃo do polimento eletrolÃtico do efluente de lagoas de estabilizaÃÃo, foram conduzidos testes em cÃlulas eletrolÃticas de 4,0 L operando em batelada, variando-se algumas configuraÃÃes, tais como pH, velocidade de agitaÃÃo e concentraÃÃo de eletrÃlito. Com base na eficiÃncia de reduÃÃo de DQO foram determinadas as configuraÃÃes Ãtimas para o conjunto de eletrodos onde houve maior remoÃÃo de matÃria orgÃnicadurante os ensaios, a partir do delineamento experimental Box-Behnken. Observou-se que as configuraÃÃes Ãtimas para os eletrodos de aÃo carbono foram 7,91 de pH inicial, 210 rpm develocidade de agitaÃÃo e 0,5049 mg/L de NaCl de concentraÃÃo de eletrÃlito e 10 minutosde tempo de reaÃÃo. Nestas condiÃÃes foram obtidas remoÃÃes de DQO de69,20%, de DBO de 89,29 % e ainda fÃsforo total e coliformes totais de 100%, adequando o efluente ao lanÃamento em corpo receptor. / This paper proposed a wastewater polishing alternative by electrocoagulation / flocculation technique. The study investigated the application of this technology with two sets of electrodes, aluminum and carbon steel, polish the effluent from the treatment plant of Nova MetrÃpole, located in Caucaia, CearÃ. The technique of application for wastewater treatment studies were carried out in bench level. In order to assess the technical and economic feasibility of the implementation of electrolytic polishing of wastewater stabilization ponds, tests were conducted in 4,0 L of electrolytic cells operating in batch, varying some settings, such as pH, stirring speed and the concentration of electrolyte. Based on COD reduction efficiency were determined the optimal settings for the set of electrodes where there was a greater removal of organic matter during the tests, from the Box-Behnken experimental design. It was noted that the optimal settings for the carbon steel electrodes were the initial pH 7,91, 210 rpm stirring speed and 0,5049 mg/L de NaCl electrolyte concentration, and 10 minutes reaction time. Under these conditions COD removals were obtained from 69,20% of BOD 89,29% and total phosphorus and total coliforms 100%, adjusting the effluent to launch in receiving body.
47

Estudo da RemoÃÃo de Cor de Efluente TÃxtil por EletrocoagulaÃÃo / Study of the Color Removal of Textile Wastewater by Electrocoagulation

Germana de Paiva Pessoa 27 June 2008 (has links)
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / A cor dos efluentes tÃxteis oriunda das estruturas polimÃricas dos corantes à um problema para as indÃstrias tÃxteis. Dentre as tÃcnicas para o tratamento desse tipo de efluente, ressalta-se a eletrocoagulaÃÃo (EC), a qual consiste em uma tÃcnica fÃsico-quÃmica aplicada tanto para remoÃÃo de cor como para poluentes orgÃnicos. Neste trabalho, avaliaram-se, em sistema de batelada, trÃs etapas do processo EC na remoÃÃo de cor de corantes. Na primeira etapa (efluente sintÃtico e eletrodos de alumÃnio primÃrio) foi utilizado o corante reativo, Remazol Blue RR, onde verificou-se o efeito dos parÃmetros operacionais, tais como: densidade de corrente, o pH inicial da soluÃÃo, tempo de eletrÃlise, concentraÃÃo inicial do corante, condutividade da soluÃÃo, demanda quÃmica de oxigÃnio (DQO) e o consumo de energia, obtendo-se uma remoÃÃo de cor de 98% e 100%, em um tempo de tratamento de 20 e 40 minutos, respectivamente. Nas condiÃÃes operacionais otimizadas, foram obtidos 98% remoÃÃo de cor e 97% de DQO, sendo o custo do processo de R$ 2,62 por m3 de efluente tratado. Na segunda etapa (efluente sintÃtico e eletrodos de latinhas reciclÃveis), verificou-se uma remoÃÃo de cor de 90% e 95% para o tempo de tratamento de 20 e 30 minutos, respectivamente. Ressalta-se que, para o tempo de 20 minutos, o custo operacional foi de R$ 0,95, enquanto que, para 30 minutos foi de R$ 1,42 por m de efluente tratado. Na terceira etapa utilizou-se efluente tÃxtil real, proveniente da indÃstria BenatÃxtil localizada na cidade de Fortaleza - Cearà e eletrodo de alumÃnio primÃrio. O melhor resultado de remoÃÃo de cor foi de 77,63%, com diluiÃÃo de 5%, tempo de tratamento de 30 minutos e pH inicial 3,0. O custo energÃtico calculado para essa etapa foi de R$ 2,01 por m3 de efluente tratado. Nesse estudo foi possÃvel verificar que o processo de eletrocoagulaÃÃo pode ser eficiente na remoÃÃo de cor de um efluente sintÃtico constituÃdo por corantes, mas que, para o efluente tÃxtil real sem nenhum tratamento prÃvio faz-se necessÃrio a diluiÃÃo do mesmo, devido à alta concentraÃÃo do corante e elevada condutividade. / The textile effluent color resultant from dyes polymeric structures is a problem for textile industries. Amongst the treatment techniques for this type of effluent, it is emphasized the electrocoagulation (EC), which consists of a physicochemical technique applied for either color or organic pollutants removal. In this work, three stages of the EC process, in batch, for dye color removal were assessed. In the first stage (synthetic effluent and primary aluminum electrodes), the reactive dye Remazol Blue RR was used and the effect of operational parameters such as electric current density, initial solution pH, electrolysis time, initial dye concentration, solution conductivity, chemical oxygen demand (COD) and the energy consumption was verified, reaching a color removal of 98% and 100%, for the treatment time of 20 and 40 minutes, respectively. In the optimized operational conditions, 98% of color removal and 97 % of DQO removal were obtained, resulting a process cost of R$ 2,62 per m3 of treated effluent. In the second stage (synthetic effluent and electrodes made from cans), a color removal of 90% and 95%, for the treatment time of 20 and 30 minutes, was verified, respectively. It is important to mention that, for the time of 20 minutes, the operational cost was R$ 0,95, whereas, for 30 minutes, was R$ 1,42 per m3 of treated effluent. In the third stage, real textile effluent from BenatÃxtil, a textile industry located in Fortaleza city â CearÃ, and primary aluminum electrodes were used. The best result for color removal was 77,63%, with dilution of 5%, treatment time of 30 minutes and initial pH 3,0. The calculated energy cost for this stage was of R$ 2,01 per m3 of treated effluent. In this study it was possible to verify that the electrocoagulation process can be efficient in the color removal of a synthetic textile effluent composed of dyes, but, for the real textile effluent without a previous treatment, it is necessary to dilute it due to its high dye concentration and conductivity.
48

Desenvolvimento de tecnologia alternativa para tratamento de efluentes de oficinas mecânicas utilizando eletrocoagulação / Development of alternative thecnology for mechanical wastewater treatment using electrocoagulation

Arcego, Cláudio Vinicius 13 March 2017 (has links)
Submitted by Marilene Donadel (marilene.donadel@unioeste.br) on 2018-11-01T18:50:41Z No. of bitstreams: 1 Claudio_Arcego_2017.pdf: 4023110 bytes, checksum: 6d506c53df527a65d8c713589651c016 (MD5) / Made available in DSpace on 2018-11-01T18:50:41Z (GMT). No. of bitstreams: 1 Claudio_Arcego_2017.pdf: 4023110 bytes, checksum: 6d506c53df527a65d8c713589651c016 (MD5) Previous issue date: 2017-03-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The Technologies used for treatment of automotive centers, gas stations and car wash stations wastewaters, available in the market have a number of operational limitations. This background, combined with the vehicle fleet increases, requires new technologies for this aim. In this context the mean goal of this work is develop an alternative technology for automotive centers and car wash stations wastewaters treatment. The methodology included: 1) a characterization of the effluent generation sources; 2) qualitative and quantitative characterization of the studied effluent; 3) technological prospecting; 4) the technology proposition; 5) the design and construction of the prototype; 6) experimental planning and performance of operational tests in laboratory conditions; 7) a proposal and systematization of the new technology; And 8) intellectual protection. It should be noted that the main parameters evaluated in this work were the apparent color, turbidity, pH and COD. The technology resulting from this work, for a condition with a higher effluent concentration (C0 = 2.5 mg.mL-1), with pH = 7 and current density (σ) of 3.42 mA.cm- ² presented higher efficiency in the removal of apparent color 99.71%) and turbidity (99.75%). The best performance in reducing the COD (93.5% removal) occurred under the conditions of test 12 (C0 = 1.5 mg.mL-1, σ = 3.42 mA / cm², pH = 10). The pH of the effluents was studied in the range of 4 to 10 and at this condition, it was observed a directly proportional influence between pH and the removal efficiency. After the results systematization and previous inventive activity evaluation, the technology for wastewater treatment must be object of intellectual protection in the National Institute of Industrial Property (INPI). The innovation is classified like Utility Model, since it is a creation of form, structure and disposition, involving an inventive act that resulted in functional improvement. / As tecnologias de tratamento e aproveitamento de efluentes de oficinas mecânicas, postos de combustíveis e de lavagem de veículos, disponíveis no mercado, ainda apresentam uma série de limitações técnicas. Esse cenário, aliado ao crescimento da frota de veículos, exige o desenvolvimento e a proposição de novas tecnologias. Nesse contexto, o objetivo do trabalho foi desenvolver uma tecnologia alternativa para o tratamento de efluentes de oficinas mecânicas e postos de lavagem automotiva. A metodologia contemplou: 1) a caracterização das fontes de geração dos efluentes (Estabelecimentos localizados no Município de Toledo-PR); 2) a caracterização qualitativa e quantitativa do efluente em estudo; 3) a prospecção tecnológica; 4) a proposição da tecnologia; 5) o projeto e construção do protótipo; 6) planejamento experimental e realização de testes operacionais em condições laboratoriais; 7) a proposição e sistematização da nova tecnologia; e 8) a proteção intelectual. Destaca-se que os principais parâmetros avaliados neste trabalho foram a cor aparente, turbidez, pH e DQO. A tecnologia resultante deste trabalho, para uma condição de maior concentração do efluente (C0=2,5 mg.mL-1), com pH=7 e densidade de corrente (σ) de 3,42 mA.cm-2 apresentou maior eficiência na remoção de cor aparente (99,71%) e turbidez (99,75%). O melhor desempenho na redução da DQO (93,5% de remoção) ocorreu nas condições de C0=1,5 mg.mL- 1, σ=3,42 mA.cm-2 e pH=10. O pH dos efluentes em estudo se encontram na faixa de 4 a 10 e nessa condição foi constatado uma influencia diretamente proporcional na eficiência de remoção dos parâmetros avaliados. Após a sistematização dos resultados e prévia avaliação da atividade inventiva, a tecnologia para o tratamento de efluentes de diversas fontes, em particular de oficinas mecânicas, deve ser objeto de proteção intelectual junto ao Instituto Nacional de Propriedade Industrial (INPI). A inovação está classificada na categoria Modelo de Utilidade, pois trata-se de uma criação de forma, estrutura e disposição, envolvendo ato inventivo que resultou em melhoria funcional.
49

Efeitos da radiofreqüência nas características mecânicas da cápsula anterior do ombro de coelhos / Radiofrequency effects on mechanical characteristics of anterior shoulder capsule of rabbits

José Luiz Pozo Raymundo 17 July 2007 (has links)
INTRODUÇÃO - A literatura mostra a utilização da radiofreqüência como alternativa em casos de redundância ou frouxidão de tecido, podendo ser empregada como solução em alguns casos de instabilidade de ombro. O presente estudo avalia os efeitos mecânicos da radiofreqüência em cápsulas anteriores de ombros de coelhos vivos. MÉTODOS O estudo é comparativo e randomizado, tendo sido realizado em trinta e sete ombros de coelhos, machos, da raça Nova Zelândia, na faixa etária de 4 meses 6 meses, com peso médio de 3kg 250mg, criados para o projeto e mantidos no Biotério Central da Universidade Federal de Pelotas UFPEL - RS. O trabalho consta de dezoito ombros do grupo controle sendo estes abertos para gerar instabilidade e não submetidos ao procedimento de radiofreqüência; e dezenove ombros do grupo experimento (radiofreqüência), abertos para gerar instabilidade e submetidos a radiofreqüência com tempo fixado em 7segundos numa temperatura fixa de 650C, com tecido embebido em solução salina. Após cinqüenta dias de pós operatório, os animais foram levados à eutanásia. O material foi mantido em -21,40C por quinze dias e, após transportado para o Laboratório de Investigação Medica 21 da Universidade de São Paulo USP - SP, para avaliação de nove variáveis: altura, comprimento inicial sem carga, área da cápsula, força máxima, deformação máxima, tensão máxima, deformação relativa, rigidez e módulo de elasticidade. RESULTADOS Foram encontradas diferenças estatisticamente significantes entre os grupos controle e o grupo radiofreqüência, para as variáveis força máxima e rigidez (p<0,05), sendo maiores em média, no grupo controle. CONCLUSÃO Desse modo a força máxima e a rigidez da cápsula anterior de ombros de coelhos vivos, submetidas à radiofreqüência em um único ponto, diminui após cinqüenta dias / INTRODUTION literature presents radiofrequency as an alternative tool to be used in redundancy or tissue looseness cases, and to be employed as a potencial solution for shoulder instability. The present study evaluated the mechanical effects of radiofrequency usage in anterior shoulder capsules of living rabbits. METHODS - the study is comparative and randomized, it was carried out with thirty seven shoulders of male rabbits (New Zealand breed), with ages between 4 to 6 months, weighing on average 3kg250g that were raised for the project and kept at Central Biotery from Federal University of Pelotas RS. The study groups encompassed eighteen shoulders as a control group that were operated to generate instability but were not submitted to radiofrequency procedure; and nineteen shoulders as intervention group (radiofrequency), that underwent the same operation procedure but were submitted to radiofrequency by the period of seven seconds at a steady temperature of 650C, the tissue was Embedded in salt solution. Fifty days after surgery the rabbits were taken to euthanasia. The material was kept at - 21,40C for fifteen days and later was taken to the São Paulo University-USP Medical Investigation Laboratory(#21), for the assessment of nine variables: height, unloaded inicial length, capsule area, maximum strength, maximum deformation, maximum tension, relative deformation, stiffness and elasticity module. RESULTS Statistical differences were observed between groups concerning maximum strength and stiffness(p<0.05), that were higher on average in the contrl group. CONCLUSION Maximum strength and stiffness of the anterior shoulder capsule in living rabbits, submitted to radiofrequency in a single spot, decreases after fifty days
50

Endocrine-Disrupting Compounds: Measurement in Tampa Bay, Removal from Sewage and Development of an Estrogen Receptor Model

Cook, Monica Mion 01 January 2015 (has links)
The significance of endocrine-disrupting compounds (EDCs) in the environment has only recently come to the forefront of scientific research, policy debates, water utilities management and public awareness. EDCs have the ability to interfere with the normal functioning of the endocrine system of humans and other animals. Numerous chemicals are included in the class of compounds known as EDCs, and exposure is widespread. These compounds are found in a variety of environmental matrices (e.g., marine and freshwater systems, sediment, soil), transported there primarily through sewage effluent discharge and recycling of sewage sludge for topical fertilizer use. This transport to the environment serves as the primary route of exposure for aquatic and terrestrial organisms living there. Furthermore, these compounds are also found in consumer products, food and drinking water--which serve as the exposure source for human beings. Multiple examples of endocrine disruption have been documented in humans and animals, and certain EDCs have been implicated in each case. The future of public and environmental health will depend upon mitigating the effects of these chemicals. This purpose of this dissertation is to provide an initial understanding of EDC occurrence in the Tampa Bay region of south Florida, and to complement the existing body of EDC research with regards to marine systems. It focuses on estrogenic EDCs, specific compounds which target the estrogen axis of the endocrine system. Six estrogenic EDCs were chosen based on their documented prevalence in the environment, prevalence in sewage, and for their suspected endocrine-disrupting effects: estrone, 17β-estradiol, estriol, 17α-ethinylestradiol, bisphenol-A and nonylphenol. These compounds were verified to be amenable to and detectable by gas chromatography-mass spectrometry analysis. Since the occurrence of EDCs in aquatic environments of the Tampa Bay region had not been previously characterized, the initial phase of the research focused on quantification of the six estrogenic EDCs in Tampa Bay area water, sediment, and sewage influent and effluent. All targeted EDCs were present in 89% of sewage samples, while 100% of the samples contained at least one or more EDCs. The concentrations of EDCs in marine aqueous and sediment samples tended to decrease with increasing distance from the wastewater treatment plant discharge site. The ubiquitous presence of these estrogenic EDCs in the Tampa Bay area is cause for concern with respect to endocrine disruption in local terrestrial and aquatic wildlife. Since the Tampa Bay region is home to a wide variety of marine organisms, constant exposure to EDCs could result in ecosystem-level effects, as these compounds can impair reproductive fitness and lead to other adverse health effects. This research also served to enlarge the existing scientific literature on EDC occurrence, as many marine and freshwater systems continue to be characterized globally. The very basis for expecting to find EDCs in the Tampa Bay area had come from the fact that the main source of environmental contamination is typically the effluent discharge from area wastewater treatment plants. Conventional wastewater treatment plant processes are designed to reduce the amount of organic matter, pathogens and nutrients from the incoming influent. However, the processes are not as effective in removing micropollutants, including EDCs. These compounds notoriously evade traditional wastewater treatment technologies and are found even in tertiary-treated effluent. For this reason, the second phase of the research assessed an electro-chemical technique for the removal of the same six EDCs. The removal technique was tested on a laboratory scale and has a commercial-sized counterpart which can be integrated at the level of the wastewater treatment plant. In order to test the removal efficiency, samples of influent and tertiary-treated effluent were spiked with the six EDCs. The mean concentration of each EDC component was statistically lower after treatment (removal range = 42% - 98.2%), demonstrating the effectiveness of this electro-chemical process for EDC removal from both raw and treated sewage. The significance of the results lies in the fact that if this method is implemented, then future wastewater treatment plant effluent discharge (similar to that of the Tampa Bay region) could be less impacted by EDCs and therefore cleaner for the environment into which it is being discharged. For the final phase of the research, the use of computational techniques to simulate human endogenous estrogen binding to its receptor was started as a foundation for future models to eventually predict endocrine-disrupting potential of different chemical compounds. We built an estradiol-human estrogen receptor model, and used molecular dynamic simulations to determine the binding free energy. The calculated total binding free energy of estradiol bound to the ligand binding domain of the human estrogen receptor was found to be -16.85 kcal/mol, which is in range of the experimental value of -12.40 kcal/mol. Humans are chronically exposed to low doses of EDCs every day, which makes endocrine disruption a considerable public health issue. Human exposure to EDCs is completely different from marine organism exposure, but the adverse effects are no less significant. The successful completion of this model serves as a platform for 1. Testing the human model against endocrine-disrupting compounds, 2. Subsequent models that will be developed for different species, including marine species important to Tampa Bay. Substantial data exist regarding the exposures and health risks associated with EDCs in humans and wildlife on a global scale. As the pressing issues of climate change and carbon emissions are at the top of the list of environmental concerns, it is important to note that mitigating the effects of EDCs should not be overlooked and will be an important responsibility of regulatory agencies in the near future.

Page generated in 0.0557 seconds