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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.
41

Environmental applications of manometric respirometric methods

Roppola, K. (Katri) 22 April 2009 (has links)
Abstract In this work a manometric respirometric measuring system was applied to practical environmental cases related to wastewater management and biodegradation studies of oil-contaminated soils and materials used in landfill structures. Pollution of groundwater, surface water and soils is a worldwide problem. Therefore, tests simulating the biodegradation behaviour of organic compounds in water media and soils have become increasingly important. Respirometric methods provide direct measurement of the oxygen consumed by micro-organisms in biodegradation processes from an air or oxygen-enriched environment in a closed vessel. Biochemical oxygen demand (BOD) is a crucial environmental parameter used to measure the quality of water and treatment results in wastewater. Generally, BOD is measured with standardised methods, which are usually time-consuming as well as laborious. In this work the manometric respirometric test was compared with conventional BOD tests by determining the BOD of pulp and paper mills as well as domestic wastewater samples. The effect of different factors such as type, amount and pre-treatment of inoculum and the effect of dilution of a sample on the BOD values were also tested. A right dilution was noticed to be the most significant factor affecting the BOD values of the industrial wastewater samples. The mathematic estimation of the BOD7 values from the respirometric data was proved to work reliably after a 2–3 day incubation period. Characterisation of organic fractions of the pulp and paper mill wastewater was carried out with methods including filtration, long term BOD measurements and COD analyses. The most significant observation in characterisation analyses was that a remarkable part of the detected oxygen demand was consumed for the biotransformation of biodegradable fractions into new inert decomposition products, not only for mineralisation of the biodegradable COD fraction. Biodegradation behaviour of the peat samples with different decomposition rates was studied in order to evaluate the applicable peat types that can be used in landfill structures. Only minor (BOD/ThOD < 0.4%) biodegradation was observed with compaction peat samples, and the stable state, in which biodegradation stopped, was achieved during a two month period. The manometric respirometric method was also applied for the biodegradation studies in which the effect of the modification of soil properties on biodegradation rates of bio-oils was tested. Modified properties were the nutrient content and the pH of the soil. Fertiliser addition and pH adjustment increased both the BOD/ThOD% values of the model substances and the precision of the measurement. The manometric respirometric method was proved to be an advanced method for simulating biodegradation processes in soil and water media.
42

Characteristics of natural organic matter in Hong Kong's source drinking water and its association with the formation of disinfection by-products

Hong, Huachang 01 January 2008 (has links)
No description available.
43

Polimerização por plasma de éter e ésteres orgânicos: caracterização e possíveis usos em microeletrônica. / Plasma polymerization of ethyl ether and ethyl or methyl acetate: film caracterization and microeletronic uses.

Roberto da Rocha Lima 30 June 2004 (has links)
O presente trabalho teve por objetivo verificar a possibilidade de obtenção de filmes finos pela polimerização por plasma de éter etílico, acetato de metila e de etila, e testes dos referidos filmes quanto à possibilidade de adsorção de compostos orgânicos polares, pois filmes adsorventes podem ser usados na construção de sensores e pré-concentradores. Utilizou-se para a polimerização por plasma os reagentes puros, mistura de éter etílico com oxigênio ou acetona ou os acetatos de metila e etila. Em todos os casos obtiveram-se filmes sobre substrato de silício e estes filmes apresentaram pouco ou nenhum descolamento por cerca de um ano. Os filmes foram caracterizados por perfilometria, para determinar a taxa de deposição, por espectroscopia de infravermelho, para avaliar as espécies polares e medida de ângulo de contato com uma gota de 4 µL de água destilada e soluções aquosas de 2-propanol ou acetona, para comprovar o caráter hidrofílico e organofílico, respectivamente. Os filmes a base de éter etílico apresentaram taxas de deposição entre 80 e 300 Å/min, além de alta intensidade relativa da banda de OH, medida por espectroscopia de infravermelho. Os ângulos de contato ficaram próximos a 75°, mostrando uma superfície hidrofílica. Adição de oxigênio ao plasma favoreceu a oxidação da molécula, conseqüente formação de CO e aumento da medida de ângulo de contato. Acetona, por sua vez, além de favorecer a produção de CO aumenta a formação de particulados e a medida de ângulo de contato. Deposição em câmara fechada favorece o aumento da taxa de deposição e formação de OH, além de pequena diminuição da medida de ângulo de contato. Adições dos acetatos de metila e/ou etila torna o sistema complexo e de difícil controle. Para os ésteres obteve-se janela de processo estreita, onde para acetato de metila observaram-se taxas de deposição maiores e medidas de ângulo de contato menores, entre 160 e 510 Å/min, e 54° a 68°, respectivamente, o que prova que a superfície é hidrofílica. A espectroscopia de infravermelho mostrou bandas semelhantes às bandas encontradas para éter etílico. Deposição em câmara fechada aumentou a taxa de deposição e favoreceu a diminuição das medidas de ângulo de contato. No plasma de acetato de etila observaram-se taxas de deposição alta e ângulos de contato intermediários entre filmes a base de éter etílico e acetato de metila, entre 350 e 1200 Å/min, e 61° a 72°, respectivamente. A superfície é hidrofílica e a espectrocopia de infravermelho mostrou bandas semelhantes às bandas encontradas para éter etílico, porém a banda CO apresenta alta intensidade relativa. A deposição em câmara fechada aumentou a taxa de deposição e a intensidade relativa de CO, obtendo-se ângulos de contato menores se comparados aos da deposição em fluxo contínuo.A medida de ângulo de contato para soluções aquosas de 2-propanol e acetona mostrou que os filmes são organofílicos e que apresentam maior afinidade por 2-propanol. A deposição sobre estrutura padrão em alumínio mostrou boa conformidade de degrau para todos os filmes. Medidas em microbalança de quartzo mostraram que os filmes adsorvem compostos orgânicos polares. Deposição dos filmes de éter e ésteres sobre filme a base de hexametildissilazana mostrou a formação de um filme contínuo, mas que rapidamente apresenta estresse, apesar de não ocorrer descolamento. A deposição sobre placas planas de acrílico mostrou um filme aderente tanto para éter etílico quanto para os ésteres. Estes filmes se apresentam hidrofílicos e organofílicos. Microcanais usinados em acrílico demonstraram a possibilidade do uso do filme na produção de estruturas pré-concentradoras. / The aim of this work is to characterize thin films obtained by plasma polymerization of ethyl ether, ethyl or methyl acetate. The films were tested for adsorption of polar organic compounds in order to evaluate their use for sensors or preconcentrators manufacturing. It was tried plasma polymerization of pure reactants and mixtures of ethyl ether with oxygen, acetone, methyl or ethyl acetate. For all reactants and mixtures films were obtained on silicon and peeling did not occur during one year of observation. Measurements of profilemeter, infrared spectroscopy, contact angle for drop of water, 2-propanol and acetone aqueous solutions were used to determine deposition rate, polar species and hydrophilic or organophilic character, respectively. For ethyl ether the films show a deposition rate between 80 and 300 Å/min and high OH relative intensity. Water contact angles were approximately 75º for all films, therefore the surfaces are hydrophilic. Oxygen addition to the plasma favors ethyl ether oxidation, increase in CO relative intensity and water contact angle. Acetone addition favors rise not only in CO relative intensity and water contact angle but also in particle formation. Deposition on closed chamber mode favors the increase of deposition rate and OH formation but the diminish on water contact angle. Mixture with methyl or ethyl acetate turns the system complex and difficult to control. The acetates process window acetates were narrow but presented higher deposition rates, from 160 A/min to 510 A/min, and lower water contact angles, from 54 º to 68º. Infrared spectroscopy shows the same species found for ethyl ether deposition. Deposition on closed chamber mode increases deposition rate and decreases the water contact angle. Ethyl acetate plasmas show high deposition rate but low water contact angle values when compared to methyl acetate. The deposition rates and water contact angles lie between 350 and 1200 A/min and 61º and 72º, respectively. Infrared spectroscopy shows the same species found on ethyl ether deposition but co presents high relative intensity. Deposition on closed chamber mode not only rises the deposition rate and CO relative intensity but also lowers the water contact angle. Contact angle measurements for 2-propanol and acetone aqueous solution show the surface is organophilic and show bigger affinity for 2-propanol aqueous solution. Deposition on aluminum lines deposited on silicon shows conformal deposition for all films. Quartz crystal measurements show the films adsorb polar organic compounds. Plasma deposited ethyl ether, methyl or ethyl acetate films on plasma deposited hexametyldisilazane substrates showed a continuous film that easily stress, although peeling was not observed. Deposition on poly(methyl methacrylate) showed good adhesion for all films. These films are also hydrophilic and organophilic. Micromachinned microchannels showed the possibility of adsorption and preconcentrators development.
44

Aerosol and Volatile Organic Compound Emissions during PolyGel® Application and Removal

Gould, Jory 25 May 2022 (has links)
No description available.
45

Study on isoprene emission from leaves of bamboo species / タケ個葉からのイソプレン放出に関する研究

Chang, Ting-Wei 24 September 2021 (has links)
京都大学 / 新制・課程博士 / 博士(農学) / 甲第23522号 / 農博第2469号 / 新制||農||1087(附属図書館) / 学位論文||R3||N5353(農学部図書室) / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 小杉 緑子, 教授 北山 兼弘, 教授 柴田 昌三 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM
46

Production and Biodegradation of Dissolved Carbon, Nitrogen and Phosphorous from Canadian Forest Floors

Turgeon, Julie January 2009 (has links)
No description available.
47

Controls on the soil solution partitioning of dissolved organic carbon and nitrogen in the mineral horizons of forested soils

Kothawala, Dolly N., 1972- January 2009 (has links)
No description available.
48

Controls on the soil solution partitioning of dissolved organic carbon and nitrogen in the mineral horizons of forested soils

Kothawala, Dolly N. January 2009 (has links)
Note:
49

Spatial variation in soil organic carbon and stable carbon isotope signature in a pasture and a primary forest in central Panamá

Abraham, Muriel January 2004 (has links)
No description available.
50

Production and biodegradation of dissolved carbon, nitrogen and phosphorus from Canadian forest floors

Turgeon, Julie. January 2008 (has links)
No description available.

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