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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.
51

Chlorination of Organic Material in Agricultural Soil

Vali nia, Salar January 2009 (has links)
Chlorine is an essential building block in the environment and can be found in most places. Chlorine participates in a complex biogeochemical cycle and has been discussed for many years and it is well documented that natural chlorination of organic compound takes place in many parts of the ecosystem. Chlorine can be inorganic (Clin) and organically bound (Clorg). Previous studies have shown that the transformation of Clin to Clorg is connected with the amount of organic matter and the microbial activity in the soil. So far, studies have been focused on forest soil and there is a need for analysing the natural chlorination in other soil types. The aim of this study was to provide chlorination rates in agricultural soil which does not weem to have been done previously. Three common agricultural soils experiencing different agricultural practice and different cropping systems were incubated with Na36Cl at 20o C in a 56 days radiotracer experiment. The results show that a chlorination of 36Clin to 36Clorg in agricultural soil occurred and the Clorg levels increased over time. The chlorination rates ranged from 0,040 to 0,063 μg Cl g dry weight soil-1 d1. This was 10-fold lower than rates previously measured in coniferous forest soil. However, when expressed as μg Cl g dry weight organic carbon-1 d-1, rates in the agricultural soil was only slightly (at the most 2-fold) lower than in coniferous forest. This study contributes with new knowledge of natural chlorination rates in agricultural soil and gives further evidence that the natural chlorination can be connected to the amount of organic matter in the soil.
52

Caracterizacao e otimizacao analitica na determinacao de trialometanos em aguas potaveis por purga e armadilha acoplada a cromatografia a gas / Analytical characterization and optimization in the determination of trihalomethanes on drinking water by purge and trap coupled to a gas chromatography

COSTA JUNIOR, NELSON V. da 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:27:35Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:07:31Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
53

Avaliação em escala real da formação de THMs em águas de abastecimento

Cesco, Décio Dias [UNESP] 16 August 2007 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:29:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-08-16Bitstream added on 2014-06-13T20:38:39Z : No. of bitstreams: 1 cesco_dd_me_ilha.pdf: 575055 bytes, checksum: 812d7bbf5c5a525f1a7625caabd57c5c (MD5) / A cloração das águas na presença de precursores da formação de SPDs, oriundos da MON forma entre estes os THMs, cujos principais compostos são o clorofórmio, bromodiclorometano, dibromoclorometano e bromofórmio, potencialmente cancerígenos ao ser humano. No ano de 1974, os THMs foram detectados na água potável nos Estados Unidos e estudos da época apresentaram as primeiras indicações da existência de correlação entre água de abastecimento, THMs e câncer e, estudos posteriores, levaram à fixação de valores limites dos mesmos. No Brasil o valor máximo para os THMs está fixado em 100 g/L na água para consumo humano, de acordo com a Portaria nº. 518/04 (BRASIL, 2004), mas estes valores limites são variáveis em outros países. O presente estudo buscou identificar a formação de THMs, gerados a partir da reação do cloro com a MON, avaliando a formação com e sem a pré-oxidação com cloro na ETA da SABESP de Presidente Epitácio SP, em escala real, onde as concentrações da MON foram reduzidas pelas etapas do processo de tratamento (coagulação, floculação, decantação e filtração), com a mudança do coagulante de cloreto férrico para PAC e, avaliou-se a formação de THM na rede de distribuição. A quantificação de THM foi realizada pelas técnicas de cromatografia gasosa e da MON através da leitura da absorbância à radiação ultravioleta visível no comprimento de onda a 254 nm em espectrofotômetro UV254, parâmetro indireto com filtração da amostra. As análises da MON mostraram que o sistema de tratamento de água não removeu todos compostos orgânicos naturais, que na presença do cloro residual disponível na rede, mostrou tendência de aumentar a formação de THM durante o seu percurso. / The chlorination of the water, when the presence of disinfections by-products are formed, resulting from Natural Organic Matter (NOM), forms among them the trihalomethanes (THMs), which is mainly composed by chloroform (CHCl3), bromodichloromethane (CHBrCl2), dibromochloromethane (CHBr2Cl) and bromoform (CHBr3), that are potentially cancerous to humans. In 1974, the THMs were detected in the drinking water in the USA and studies, at the time, showed the first indications of the drinking water correlation, THMs and cancer disease and, further studies brought to fixation of limits for them. In Brazil, the maximum value for the THMs is fixed in 100μg/l in the drinking water, according to government act nº 518/04 (BRASIL, 2004), however those limits varied from country to country. The present research identified the formation of THMs, generated from the reaction of the chlorine with NOM, evaluating the formation with or without the pre-oxidation with chlorine in the SABESP Water Treatment Plant at the Presidente Epitacio city (São Paulo State), in full scale, where the concentrations of the NOM were reduced by the different phases of the treatment process (coagulation, flocculation, decantation and filtration), with the change of the coagulant from iron chloride to Poli Aluminum Chloride (PAC) and, the formation of THM was found at the distribution net. The quantification of THM was made by the gas chromatography technique and NOM are reading in the 254 nm absorbance radiation wave length in an UV spectrophotometer, indirect sample with filtration. The analysis of the NOM showed that the water treatment system did not remove all the natural organic compounds, that in the presence of residual chlorine available in the net, showed increasing tendency to form THM.
54

Avaliação em escala real da formação de THMs em águas de abastecimento /

Cesco, Décio Dias. January 2007 (has links)
Resumo: A cloração das águas na presença de precursores da formação de SPDs, oriundos da MON forma entre estes os THMs, cujos principais compostos são o clorofórmio, bromodiclorometano, dibromoclorometano e bromofórmio, potencialmente cancerígenos ao ser humano. No ano de 1974, os THMs foram detectados na água potável nos Estados Unidos e estudos da época apresentaram as primeiras indicações da existência de correlação entre água de abastecimento, THMs e câncer e, estudos posteriores, levaram à fixação de valores limites dos mesmos. No Brasil o valor máximo para os THMs está fixado em 100 g/L na água para consumo humano, de acordo com a Portaria nº. 518/04 (BRASIL, 2004), mas estes valores limites são variáveis em outros países. O presente estudo buscou identificar a formação de THMs, gerados a partir da reação do cloro com a MON, avaliando a formação com e sem a pré-oxidação com cloro na ETA da SABESP de Presidente Epitácio SP, em escala real, onde as concentrações da MON foram reduzidas pelas etapas do processo de tratamento (coagulação, floculação, decantação e filtração), com a mudança do coagulante de cloreto férrico para PAC e, avaliou-se a formação de THM na rede de distribuição. A quantificação de THM foi realizada pelas técnicas de cromatografia gasosa e da MON através da leitura da absorbância à radiação ultravioleta visível no comprimento de onda a 254 nm em espectrofotômetro UV254, parâmetro indireto com filtração da amostra. As análises da MON mostraram que o sistema de tratamento de água não removeu todos compostos orgânicos naturais, que na presença do cloro residual disponível na rede, mostrou tendência de aumentar a formação de THM durante o seu percurso. / Abstract: The chlorination of the water, when the presence of disinfections by-products are formed, resulting from Natural Organic Matter (NOM), forms among them the trihalomethanes (THMs), which is mainly composed by chloroform (CHCl3), bromodichloromethane (CHBrCl2), dibromochloromethane (CHBr2Cl) and bromoform (CHBr3), that are potentially cancerous to humans. In 1974, the THMs were detected in the drinking water in the USA and studies, at the time, showed the first indications of the drinking water correlation, THMs and cancer disease and, further studies brought to fixation of limits for them. In Brazil, the maximum value for the THMs is fixed in 100μg/l in the drinking water, according to government act nº 518/04 (BRASIL, 2004), however those limits varied from country to country. The present research identified the formation of THMs, generated from the reaction of the chlorine with NOM, evaluating the formation with or without the pre-oxidation with chlorine in the SABESP Water Treatment Plant at the Presidente Epitacio city (São Paulo State), in full scale, where the concentrations of the NOM were reduced by the different phases of the treatment process (coagulation, flocculation, decantation and filtration), with the change of the coagulant from iron chloride to Poli Aluminum Chloride (PAC) and, the formation of THM was found at the distribution net. The quantification of THM was made by the gas chromatography technique and NOM are reading in the 254 nm absorbance radiation wave length in an UV spectrophotometer, indirect sample with filtration. The analysis of the NOM showed that the water treatment system did not remove all the natural organic compounds, that in the presence of residual chlorine available in the net, showed increasing tendency to form THM. / Orientador: Tsunao Matsumoto / Coorientador: Edson Pereira Tangerino / Banca: Milton Dall'Aglio Sobrinho / Banca: Marcelo Libânio / Mestre
55

Caracterizacao e otimizacao analitica na determinacao de trialometanos em aguas potaveis por purga e armadilha acoplada a cromatografia a gas / Analytical characterization and optimization in the determination of trihalomethanes on drinking water by purge and trap coupled to a gas chromatography

COSTA JUNIOR, NELSON V. da 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:27:35Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:07:31Z (GMT). No. of bitstreams: 0 / Neste trabalho desenvolveu-se uma metodologia analítica para determinação do teor de trialometanos THMs em amostras de águas potáveis, utilizando a técnica de purga e armadilha acoplada à cromatografia a gás (GCPT). Os THMs são subprodutos da cloração da água que devem possuir um limite máximo de 100 μg.L-1 segundo a legislação brasileira, estes compostos são suspeitos carcinogênicos humanos com base em estudos em animais de laboratório. A técnica de purga e armadilha extrai eficientemente estes compostos da água e a separação no cromatógrafo a gás ocorre utilizando coluna de leve polaridade e detector por captura de elétrons. Este detector é seletivo e o mais sensível para estes compostos halogenados. A metodologia desenvolvida foi validada nos itens de: linearidade, seletividade, exatidão, precisão, limite de quantificação, limite de detecção e robustez. O limite de detecção para os THMs foi menor do que 0,5 μg.L-1. A exatidão e precisão foram adequadas para ensaios de compostos traços. As amostras de água potável foram coletadas na cidade de Suzano-SP, que pertence à região do Alto do Tietê, nesta região nas margens do rio a vegetação é predominante. Entre todos os THMs, o composto encontrado na água potável em maiores concentrações foi o clorofórmio onde os resultados quantitativos, utilizando esta metodologia apresentaram teores entre 15,9 à 111,0 μg.L-1 em águas potáveis. / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
56

Eco/genotoxicidade do corante comercial CI Disperse Red 1 e seus subprodutos clorados / Eco/genotoxicity of commercial dye CI Disperse Red 1 and chlorinated by-products

Vacchi, Francine Inforçato, 1986- 20 August 2018 (has links)
Orientador: Gisela de Aragão Umbuzeiro / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Tecnologia / Made available in DSpace on 2018-08-20T00:20:58Z (GMT). No. of bitstreams: 1 Vacchi_FrancineInforcato_M.pdf: 2178218 bytes, checksum: c13ca17191dbaab46671272dc416c546 (MD5) Previous issue date: 2012 / Resumo: Cerca de 70% dos corantes utilizados em indústrias têxteis são corantes do tipo azo, que se caracterizam pelo grupo -N=N- ligado a sistemas aromáticos, sendo que a função azo inclui os principais tipos de corantes. A eliminação da cor no efluente é um grande desafio para o setor têxtil, já que, aproximadamente, 15% da produção mundial de corantes são descartados para o meio ambiente durante sua produção, processamento e aplicação. O corante comercial Disperse Red 1 utilizado neste trabalho é composto por seis corantes diferentes e surfactante, porém o corante principal em sua composição é o Disperse Red 1 (N-Ethyl-N-(2-hydroxyethyl)-4-(4- nitrophenylazo) aniline; CAS number 2872-52-8) com 60% em massa. O corante comercial foi submetido ao processo de cloração com gás cloro, simulando as condições utilizadas em Estações de Tratamento de Efluentes. A toxicidade do corante comercial CI Disperse Red 1 e do subproduto clorado foi avaliada em testes agudos com Ceriodapnhia dubia, Ceriodaphnia silvestrii, Daphnia similis, Daphnia magna, Hydra attenuata, e em testes crônicos com Pseudokirchneriella subcapitata, Ceriodapnhia dubia, e Hydra attenuata. A mutagenicidade foi avaliada com ensaio Salmonella/microssoma com as linhagens TA98, TA100 e YG1041. D. similis foi o organismo mais sensível ao corante comercial; e H. attenuata foi mais sensível ao subproduto clorado. A CE50 obtida para D. similis para o corante comercial é similar ao corante puro, mostrando que a toxicidade do corante comercial é devido ao Disperse Red 1. O subproduto clorado foi menos tóxico do que o corante para todos os organismos testados, com exceção de H. attenuata. Porém, o subproduto clorado foi mais mutagênico do que o corante para todas as linhagens testadas. Mais estudos são necessários para compreender os mecanismos envolvidos na toxicidade destes corantes, considerando sua alta toxicidade para organismos aquáticos, a fim de fornecer informações para a elaboração de corantes ambientalmente corretos. Os resultados obtidos neste trabalho podem fornecer informações úteis para a derivação de critérios para qualidade da água para esse corante / Abstract: About 70% of dyes used in textiles industries are of type azo. These days 15% of the dye world production is discharged into the environment during its production, processing and application. Effluent that contains dyes must have their color removed in order to be in compliance with environmental regulations, but sometimes the treatment can lead to more toxic compounds. The commercial azo dye Disperse Red 1 used in this study is composed of six different dye constituents and surfactant; however the main dye of the commercial product is the Disperse Red 1 (N-Ethyl-N-(2-hydroxyethyl)-4-(4-nitrophenylazo) aniline; CAS number 2872-52-8). Commercial dye samples were treated with chlorine gas, in order to simulate the conditions used in effluent treatment plant. The ecotoxicity of the commercial dye and chlorinated byproduct was evaluated in acute tests with Ceriodaphnia dubia, Ceriodaphnia silvestrii, Daphnia similis, Daphnia magna, and Hydra attenuata as well as in chronic toxicity tests with Pseudokirchneriella subcapitata, Ceriodapnhia dubia and Hydra attenuata. Mutagenicity was evaluated using Salmonella/microsome assay with TA98, TA100 and YG1041 strains. The commercial dye Disperse Red 1 was similarly toxic to P. subcapitata, C. dubia and D. similis, even with different endpoints. The chlorinated byproduct was less toxic to all organisms tested than the dye, except for H. attenuata. The toxicity of the commercial dye is due to Disperse Red 1 itself and the surfactant does not seem to contribute to the toxicity, at least to D. similis. The chlorinated byproduct was more mutagenic than the commercial dye. More studies are necessary to address the mechanisms involved in the toxicity of this azo dye considering its high toxicity to aquatic organisms in order to provide information for the design of more environmental friendly dye products. The results obtained in this work can provide useful information for the derivation of water quality criteria for this dye / Mestrado / Tecnologia e Inovação / Mestre em Tecnologia
57

Comparative effects of two ozonation treatments on wheat flour technological properties

Saint Paul, Julien January 1900 (has links)
Master of Science / Department of Grain Science and Industry / Finlay I. MacRitchie / Ozone, a triatomic form of oxygen with a Generally Recognized As Safe (GRAS) status from the U. S. Food and Drug Administration, is a strong antimicrobial and sanitizing agent with numerous potential applications in the food industry. One of them is the improvement of wheat flour baking qualities, by replacement of the actual chlorination treatment. Following recent developments realized by the company Goemar (France) which invented and patented an ozone treatment device for wheat grain and a method for making flour from ozone-treated grains, this study aims to determine the effect of ozone treatment on wheat grain and on wheat flour, and to compare them. Three different ozone concentrations with different application times rendering three quantities of absorbed ozone have been investigated. Rheological, physicochemical and baking properties of soft wheat flours stemming from both treatments were evaluated and compared to untreated flour. Results were overall significant and showed that the treatment of flour gives more marked results than the treatment on grain for retention capacity in sucrose and volume of cakes but decreases the [alpha]-amylase activity. On the other hand, action of ozone on grain augments the maximum viscosity of the flour. Bread volume was found to be increased by both treatments in similar proportions. The treatments were also analyzed in particular and showed specific characteristics. A single treatment has not been determined to enhance all characteristics of the flour. Hence, the modification of precise features of the flour has to be related to a specific treatment.
58

[en] TIO2 OBTAINED THROUGH ILMENITE CHLORINATION AND SEQUENTIAL CHARACTERIZATION OF THE RELATED MATERIALS / [pt] OBTENÇÃO DO TIO2 A PARTIR DA CLORAÇÃO DE UMA ILMENITA E CARACTERIZAÇÃO SEQUENCIAL DOS MATERIAIS ENVOLVIDOS

LUDY MARGARITA CACERES MONTERO 18 April 2017 (has links)
[pt] Na indústria do titânio, a ilmenita (FeOTiO2) é hoje a matéria prima com maior potencial para à obtenção de TiCl4 via cloração, como precursor do TiO2 e do Ti metálico. Neste processo, os cloretos de ferro formados podem ser materiais de partida para a formação de sais duplos com possíveis usos na armazenagem de energia térmica em usinas solares. Partindo destas premissas, o presente trabalho aborda o estudo da cloração de um material granulado rico em ilmenita, e a posterior separação dos produtos gasosos formados, através do uso de uma coluna de sal. Com a ajuda das avaliações físico-químicas (termodinâmica e cinética), na etapa de cloração foram estudados os efeitos das principais variáveis operacionais (vazão do cloro, temperatura, percentagem de agente redutor, pressão parcial do cloro) sobre a velocidade e rendimento da reação. No estudo dedicado a separação dos cloretos gasosos formados, foi aferido o comportamento e a eficiência de uma coluna de sal em leito fixo (de fórmula geral MClx), através da adsorção seletiva do cloreto de ferro e a provável formação do sal duplo FeCl3-MClx. Para a neutralização dos gases residuais contendo o excesso de cloro do processo, foram usadas soluções alcalinas com o que conseguiu-se total controle dos gases liberados na atmosfera. A caracterizados sequencial dos materiais envolvidos no processo, foi realizada com o uso de técnicas de Fluorescência de Raios X (FRX), Microscopia Eletrônica de Varredura (MEV), Espectroscopia de Energia Dispersiva (EDS), Difração de Raios X (DRX), e Microscopia Eletrônica de Transmissão (MET). Os resultados indicaram a viabilidade de formação do TiO2 rutilo (via cloração direta) e TiO2 anatasio (via carbocloração). / [en] In the titanium industry, ilmenite (FeOTiO2) is to be used as an alternative raw material with potential for obtaining TiCl4 by chlorination, and afterwards to be used as precursor of TiO2 and metal Ti. Moreover, iron chlorides formed this process, can be used as starting material for the formation of double salts with potential applications in thermal energy storage in solar power plants. Starting from these premises, this work describes the study of chlorination of a granulated material rich in ilmenite, and the subsequent separation of gaseous products formed, through the use of a salt column. Physicochemical assessments (thermodynamics and kinetics) in the chlorination stage, was studied the effects of the main operating variables (chlorine flow, temperature, percentage of reducing agent partial pressure of chlorine) on the rate and yield of the reaction. In the study dedicated to separating the formed gaseous chlorides, was determined the behavior and efficiency of a salt column of fixed bed. (bed salt, with generic form MClx), through the selective adsorption of iron chloride and the likely formation of double salt FeCl3-MClx. For the neutralization of the waste gases containing excess chlorine from the process, they were used with alkaline solutions that could be full control of the gases released into the atmosphere. The sequencial characterization of the materials involved was made using techniques of X-Ray Fluorescence (XRF), Scanning Electron Microscopy (SEM), energy dispersive spectroscopy (EDS), X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). The results indicated the feasibility of formation of TiO2 rutile, when produced by direct chlorination), and TiO2 anatase (when produced by carbochlorination).
59

Development of a security network (SECNET) based on integrated services digital network (ISDN)

Alvarez, Isidro 25 March 1996 (has links)
The progress in the computing and communication industries together with the fast evolution of the semiconductor industry has made possible advances in the communications field. These advances have been used by other related applications to improve the services that they bring about. On the other hand, business crimes have increased three digits orders of magnitude in one decade, making from 20% to 30% of small businesses fail. These conditions demand new solutions to make security systems more reliable and efficient. The present work combines ISDN as a network with a security system to create a security network (SECNET). It will create intelligent and distributed security devices that communicate information from different places to a main security office by using the ISDN lines available at the premises. This work also introduces a new idea of individual equipment protection.
60

The Application of Chlorine Dioxide to Tastes and Odors in Water Supplies

Hemphill, Louis January 1952 (has links)
This problem was undertaken to determine the potentialities of chlorine dioxide as an algaecide and as an agent for the removal of tastes and odors from fresh water.

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