• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 270
  • 70
  • 45
  • 18
  • 12
  • 11
  • 8
  • 4
  • 3
  • 3
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 512
  • 512
  • 512
  • 62
  • 58
  • 50
  • 49
  • 48
  • 48
  • 47
  • 46
  • 39
  • 39
  • 38
  • 38
  • 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.
191

Histórico da Deposição de Hidrocarbonetos Policíclicos Aromáticos em um Estuário Amazônico nos Últimos Cem Anos / Depositional Hystory of Polycyclic Aromatic Hydrocarbons in an Amazon Estuary in the Last 100 Years

Neves, Patricia Andrade 17 November 2015 (has links)
Para determinar o histórico deposicional e as fontes dos hidrocarbonetos policíclicos aromáticos (HPAs) na região amazônica nos últimos 120 anos, três testemunhos foram coletados na Baía do Guajará - PA. Esses testemunhos também foram datados com 210Pb, e analises da razão isotópica do carbono estável (δ13C) e de n-alcanos foram efetuadas. Ao longo dos três testemunhos, os resultados do δ13C e n-alcanos indicaram a predominância de matéria orgânica terrígena, derivadas de plantas do tipo C3. Entretanto, uma variação nesses valores foi observada em 1965. As concentrações de HPAs também apresentaram uma alteração por volta de 1965. Até 1965, os HPAs alquilados foram predominantes em relação à seu composto parental (metilfenantreno> fenantreno). Esses HPAs estão geralmente associados a fontes petrogênicas, entretanto, nenhuma evidência de petróleo foi observada. A maior proporção de HPAs alquilados pode estar relacionada a processos naturais, diagenéticos ou de biossíntese. Após 1965, as concentrações de HPAs aumentaram. As razões diagnósticas indicaram a predominância de HPAs pirolíticos, provavelmente relacionadas às queimadas efetuadas para criação de pastos. A diminuição do δ13C no período também deve estar relacionada à extração de madeira, que introduz uma grande quantidade de resíduos de vegetação nos sedimentos. / In order to evaluate the historical deposition and sources of PAHs over the last 120 years (1890 to 2011) in the amazon region, three sediment cores were collected from Guajara Bay (state of Pará). The cores were also dated with 210Pb and n-alkanes and carbon isotopic ratios (δ13C) were measured. Throughout the cores, the δ13C and n-alkanes indicated the predominance of organic matter from terrigenous sources (C3 plants). Even though δ13C values and n-alkanes ratios remained representative of terrigenous sources, there was an abrupt variation around the middle 1960s. PAH concentrations also showed a variation around the late 1960s. Before 1960s, alkyl-PAHs concentrations were higher than those of their parental compound (methylphenanthrene > phenanthrene). These PAHs are usually associated with petrogenic inputs; however, no evidence of oil was observed. The higher proportion of alkyl-PAHs could be related to natural diagenetic and biogenic processes. After the 60s, PAH concentrations increased and diagnostic ratios showed a predominance of pyrolytic PAH, probably related to the forest fires used to create pastures. The deforestation can also be associated to the δ13C depletion found in the sediments, due to logging activities, which introduce more organic matter derived from vascular plants into the sediment.
192

Progress towards accessing a C3v [6,6] nanotube end-cap and development of a microwave assisted anionic cyclodehydrogenation reaction

Belanger, Anthony January 2008 (has links)
Thesis advisor: Lawrence T. Scott / This dissertation describes the work that has been carried out towards accessing a C3v [6,6] nanotube end-cap through rational chemical synthesis. Continued advancement in carbon nanotube research has driven scientists to develop a successful route to usable quantities of nanotubes that are homogeneous in structure. Due to the current inability to separate nanotube mixtures efficiently, researchers in fields ranging from chemistry to computer science have been unable to exploit fully all that these unique molecules have to offer. Our envisioned approach to this obstacle involves elongation of a template endcap using iterative growth chemistry. The final stage of the proposed end-cap synthesis involves the execution of a six fold cyclodehydrogenation reaction. To carry out this desired transformation, a new microwave assisted variant of the anionic cyclodehydrogenation reaction has been developed. Through this chemistry we have been able to access a variety of both known and novel polycyclic aromatic hydrocarbons, often in impressively high yields. We hope that this chemistry will be useful to us in accessing the target nanotube end-caps, and to others in providing a new route to accessing a variety of polycyclic aromatic hydrocarbon cores. / Thesis (PhD) — Boston College, 2008. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.
193

Dos teores de hidrocarbonetos policíclicos aromáticos (HPAs) em aguardentes acondicionadas em tonéis de carvalho / Evaluation of Polycyclic Aromatic Hydrocarbons (PHAs) concentrations in sugarcane spirits storage in barrels with different times of toast and time aged.

Chávez, Irene Palerma Arias 15 April 2015 (has links)
Dependendo das etapas de produção, a aguardente de cana de açúcar, pode ser contaminada por Hidrocarbonetos Policíclicos Aromáticos (HPAs) que apresentam propriedades carcinogênicas e/ ou mutagênicas. Neste trabalho se determinou os teores de HPAs em aguardentes acondicionadas em tonéis de carvalho sem tostar e tostados por 1, 2 e 3 minutos. Os dados obtidos em função do tempo de envelhecimento e do tempo de tosta do tonel foram correlacionados. Após períodos variados, as amostras foram coletadas e submetidas a processos de extração em cartuchos de SPE (C18) e analisadas por Cromatografia Líquida de Alta Eficiência (HPLC) com detector de fluorescência. Dos 16 HPAs monitorados pela Agencia de Proteção Americana (USEPA) foram analisados: Naftaleno, Acenafteno, Fluoreno, Fenantreno, Antraceno, Fluoranteno, Pireno, Benzo(a)Antraceno, Criseno, Benzo(b)fluoranteno, Benzo(k)fluoranteno, Benzo(a)pireno, Dibenzo(a,h)antraceno, Benzo(g,h,i)perileno e Indeno(1,2,3 c,d)pireno. Os HPAs nas aguardentes armazenadas, apresentaram um perfil comum, atingindo teores máximos entre o 4° e o 12° dia de armazenamento, começando a diminuir até atingir a valores em alguns casos próximos ao do Branco. Realizaram-se dois experimentos de armazenamento, o 1º experimento ao longo de 553 dias e o 2º experimento por um período de 57 dias. As amostras armazenadas no 2º experimento (tonéis re-utilizados) apresentaram teores inferiores de HPAs em relação ao 1º experimento. A soma dos teores médios máximos dos 15 HPAs, nas amostras de aguardente armazenada no 1º e 2º experimento respectivamente foram: 1 min. de tosta (27,76 -14,45 µ/L ), sem tosta (20,34 -9,02 µg/L), 2 min. de tosta (15,45 -10,38 µg/L) e 3 min. de tosta (14,25 -12,89 µg/L). Os valores do Branco para o 1º e 2 º experimento foram: 10,88 µg/L e 6,89 µg/L, respectivamente. Com respeito ao Benzo(a)pireno (BaP), os teores médios máximos alcançados em aguardentes envelhecidas em tonéis tostados por 1, 2 e 3 minutos foram respectivamente: 0,0094 µg/L, 1,401 µg/L, 0,119 µg/L e 0,051 µg/L, atingindo teores maiores que o teor do Branco do BaP (0,014µg/L). / During the different steps of production, the sugarcane spirits can be contaminated with Polycyclic Aromatic Hydrocarbons (PAHs) which have carcinogenic and/or mutagenic properties. The scope this work is to determine the levels of PAHs in aged sugarcane spirits in oak barrels with and without toasting for later correlation of results depending on the aging time and the time of the burning barrel. The samples were stored in barrels without and with toasting for 1, 2 and 3 minutes. After varying periods, samples were collected and subjected to extraction processes using SPE (C18) cartridges and analyzed by using High Efficiency Liquid Chromatography (HPLC) coupled with a fluorescence detector. We analyzed the following PAHs: naphthalene, acenaphthene, fluorene phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, benzo(g,h,i)perylene and indeno(1,2,3-c,d)pyrene. PAHs in aged spirits had a common profile, reaching maximum levels between the 4th and 12th day of aging, starting to decrease the values, in some cases, lower than blank. There were two storage experiments, experiments 1 through 553 days and the 2nd experiment for a period of 57 days. Samples stored in the 2nd experiment (re-used barrels) had lower levels of PAHs compared to the 1st experiment. The sum of the maximum average levels of 15 PAHs in the samples spirit stored in the 1st and 2nd respectively experiment were: 1 min. of toast (27.76 -14.45 µ/L) without toast (20.34 -9.02 µg/L), 2 min. toasting (15.45 -10.38 µg/L), and 3 min. toasting (14.25 -12.89 µg/L). The blank values for the 1st and 2nd experiment were: 10.88 µg/L and 6.89 µg/L, respectively. With respect to Benzo(a)pyrene (BaP), the maximum average levels achieved in spirit aged in barrels toasted by 1, 2 and 3 minutes were respectively: 0.0094 µg/L, 1.401 µg/L, 0.119 µg/L and 0.051 µg/L, reaching higher levels than the blank content of BaP (0,014 µg/L)
194

Influência da fuligem da queima de palha de cana-de-açucar na presença de HPA em hortaliças de consumo humano /

Sugauara, Lucy Elaine. January 2014 (has links)
Orientador: Mary Rosa Rodrigues de Marchi / Banca: Mario Sergio Galhiane / Banca: Flávio Sares Silva / Resumo:Os HPA são contaminantes orgânicos formados tanto na queima da palha de cana-de-açúcar quanto de combustível fóssil e por suas características físico-químicas estão associados ao material particulado fino, podendo assim ser transportado a longas distâncias em um curto espaço de tempo dependendo das condições climáticas. Pelas características de mutagenicidade, carcinogecidade e alteração endócrina são substâncias que tem merecido interesse dos pesquisadores na avaliação da exposição humana por diversas vias, sendo a via alimentar a menos explorada atualmente. Este trabalho teve por objetivo otimizar e validar um método para determinação de HPA em hortaliças e avaliar a presença destas substancias em alface, couve e rúcula , em localidades com e sem a influência da queima de cana-de-açúcar (Araraquara e Itu). O método otimizado e validado neste trabalho envolve extração por banho de ultrassom e detecção por HPLC/FLU, possui valores aceitáveis de LD e LQ de acordo com a União Européia, 0,3 e 0,9 μg kg-1 respectivamente e valores de CV (<11,6%) e recuperação (70~119%), de acordo com os valores preconizados pela ANVISA. Amostras de alface, rúcula e couve cultivados em duas cidades em três diferentes locais, Araraquara (zona rural e zona urbana) e Itu (zona urbana) no período correspondente a safra (agosto de 2012) e entressafra (março 2013) da cana-de-açúcar foram analisadas. As concentrações de HPA encontradas nestas hortaliças situaram-se abaixo dos níveis reportados na literatura em folhas de diferentes espécies vegetais. No entanto, quando considerada a ingestão de 200g/dia, metade do preconizado pela OMS (Organização Mundial de Saúde) para ingestão diária recomendada de legumes, frutas e verduras, infere-se que a quantidade de HPA ingerida por esta via corresponderia a uma dieta de alta exposição MOE (Margin of Exposure) <10 000... / Abstract: The PAH are a class of organic contaminants which are formed in burning of sugarcane and fossil fuel. The physicochemical properties are associated with their affinity for fine particulate matter and can therefore be transported over long distances in a short time depending on the weather. The PAH have characteristics of mutagenicity, carcinogenicity and endocrine disruption, because of these characteristics they are substances that have earned interest of researchers in the evaluation of human exposure via differents routes of uptake, and currently the dietary is the less explored. This study aimed to optimize and validate a method for the determination of PAH in vegetables and evaluate the presence of these substances in lettuce , kale and arugula, in locations with and without the influence of sugarcane burning (Araraquara and Itu). The optimized and validated method in this work involves extraction by ultrasound bath and detection by HPLC/FLU, also has acceptable values of LOD and LOQ in accordance with the European Union , 0.3 and 0.9 μg kg- 1 respectively , and the CV (<11.6%) and recovery values (70 ~ 119 %), are also in accordance to the values recommended by ANVISA . Samples of lettuce , arugula and kale grown in two different cities on three sites , Araraquara (rural and urban areas) and Itu (urban area) corresponding to the harvest period (August 2012) and sugarcane off season (March 2013) were analyzed. Concentrations of PAH found in these vegetables were below the levels reported in the literature in leaves of different plant species . However, when considering the intake of 200g/day, half the daily intake of fruits and vegetables recommended by WHO (World Health Organization ) it is inferred that the amount of PAH ingested in this way corresponds to a High exposure diet with MOE ( Margin of exposure) < 10 000 near the limits considered worrisome by the European Union. / Mestre
195

Histórico da Deposição de Hidrocarbonetos Policíclicos Aromáticos em um Estuário Amazônico nos Últimos Cem Anos / Depositional Hystory of Polycyclic Aromatic Hydrocarbons in an Amazon Estuary in the Last 100 Years

Patricia Andrade Neves 17 November 2015 (has links)
Para determinar o histórico deposicional e as fontes dos hidrocarbonetos policíclicos aromáticos (HPAs) na região amazônica nos últimos 120 anos, três testemunhos foram coletados na Baía do Guajará - PA. Esses testemunhos também foram datados com 210Pb, e analises da razão isotópica do carbono estável (&#948;13C) e de n-alcanos foram efetuadas. Ao longo dos três testemunhos, os resultados do &#948;13C e n-alcanos indicaram a predominância de matéria orgânica terrígena, derivadas de plantas do tipo C3. Entretanto, uma variação nesses valores foi observada em 1965. As concentrações de HPAs também apresentaram uma alteração por volta de 1965. Até 1965, os HPAs alquilados foram predominantes em relação à seu composto parental (metilfenantreno> fenantreno). Esses HPAs estão geralmente associados a fontes petrogênicas, entretanto, nenhuma evidência de petróleo foi observada. A maior proporção de HPAs alquilados pode estar relacionada a processos naturais, diagenéticos ou de biossíntese. Após 1965, as concentrações de HPAs aumentaram. As razões diagnósticas indicaram a predominância de HPAs pirolíticos, provavelmente relacionadas às queimadas efetuadas para criação de pastos. A diminuição do &#948;13C no período também deve estar relacionada à extração de madeira, que introduz uma grande quantidade de resíduos de vegetação nos sedimentos. / In order to evaluate the historical deposition and sources of PAHs over the last 120 years (1890 to 2011) in the amazon region, three sediment cores were collected from Guajara Bay (state of Pará). The cores were also dated with 210Pb and n-alkanes and carbon isotopic ratios (&#948;13C) were measured. Throughout the cores, the &#948;13C and n-alkanes indicated the predominance of organic matter from terrigenous sources (C3 plants). Even though &#948;13C values and n-alkanes ratios remained representative of terrigenous sources, there was an abrupt variation around the middle 1960s. PAH concentrations also showed a variation around the late 1960s. Before 1960s, alkyl-PAHs concentrations were higher than those of their parental compound (methylphenanthrene > phenanthrene). These PAHs are usually associated with petrogenic inputs; however, no evidence of oil was observed. The higher proportion of alkyl-PAHs could be related to natural diagenetic and biogenic processes. After the 60s, PAH concentrations increased and diagnostic ratios showed a predominance of pyrolytic PAH, probably related to the forest fires used to create pastures. The deforestation can also be associated to the &#948;13C depletion found in the sediments, due to logging activities, which introduce more organic matter derived from vascular plants into the sediment.
196

Removal of polycyclic aromatic hydrocarbons by spent mushroom compost of oyster mushroom pleurotus pulmonarius.

January 2002 (has links)
Lau Kan Lung. / Thesis submitted in: November 2001. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 286-312). / Abstracts in English and Chinese. / List of Symbols and Abbreviations --- p.I / List of Figures --- p.III / List of Tables --- p.XII / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Polycyclic aromatic hydrocarbons (PAHs) --- p.1 / Chapter 1.1.1 --- Physical and chemical properties of PAHs --- p.1 / Chapter 1.1.2 --- Formation of PAHs --- p.5 / Chapter 1.1.3 --- Sources of PAHs --- p.9 / Chapter 1.1.4 --- Regulations for contamination of PAHs --- p.13 / Chapter 1.1.5 --- Pollution of PAHs in environments of Hong Kong --- p.17 / Chapter 1.1.6 --- Toxicity of PAHs --- p.18 / Chapter 1.1.7 --- Fate of PAHs --- p.22 / Chapter 1.1.7.1 --- Sorption --- p.24 / Chapter 1.1.7.2 --- Volatilization --- p.25 / Chapter 1.1.7.3 --- Photooxidation --- p.25 / Chapter 1.1.7.4 --- Chemical oxidation --- p.27 / Chapter 1.1.7.5 --- Microbial degradation --- p.28 / Chapter 1.1.8 --- General principles of metabolism of PAHs --- p.30 / Chapter 1.2 --- Spent mushroom compost (SMC) --- p.35 / Chapter 1.2.1 --- Production of SMC --- p.35 / Chapter 1.2.2 --- Physical and chemical properties of SMC --- p.36 / Chapter 1.2.3 --- Availability of SMC --- p.40 / Chapter 1.2.4 --- Conventional applications of SMC --- p.43 / Chapter 1.2.5 --- Alternate use of SMC --- p.44 / Chapter 1.3 --- Objectives of the study --- p.48 / Chapter 1.4 --- Research strategy --- p.51 / Chapter 1.4.1 --- Effect of initial PAH concentration --- p.51 / Chapter 1.4.2 --- Effect of initial pH --- p.52 / Chapter 1.4.3 --- Effect of incubation time --- p.53 / Chapter 1.4.4 --- Effect of incubation temperature --- p.54 / Chapter 1.4.5 --- Putative identification of intermediates and/or breakdown products --- p.54 / Chapter 1.4.6 --- Isotherm plots and fitting into monolayer models --- p.55 / Chapter 1.4.6.1 --- Langmuir isotherm --- p.56 / Chapter 1.4.6.2 --- Freundlich isotherm --- p.58 / Chapter 1.4.7 --- Toxicological study by Microtox test --- p.59 / Chapter 1.4.8 --- Removal of PAH mixtures --- p.60 / Chapter 1.4.9 --- Specific goals of the study --- p.61 / Chapter 2 --- Materials and Methods --- p.62 / Chapter 2.1 --- Materials --- p.62 / Chapter 2.2 --- Physical and chemical analysis of SMC --- p.62 / Chapter 2.2.1 --- pH --- p.63 / Chapter 2.2.2 --- Electrical conductivity --- p.63 / Chapter 2.2.3 --- Salinity --- p.63 / Chapter 2.2.4 --- Ash content --- p.63 / Chapter 2.2.5 --- Metal contents --- p.64 / Chapter 2.2.6 --- Water-soluble anion contents --- p.65 / Chapter 2.2.7 --- "Carbon, hydrogen, nitrogen and sulfur contents" --- p.65 / Chapter 2.2.8 --- Infrared spectroscopic study --- p.66 / Chapter 2.2.9 --- Chitin content --- p.66 / Chapter 2.3 --- Soil collection and characterization --- p.67 / Chapter 2.4 --- Optimization for extraction --- p.67 / Chapter 2.5 --- Removal of PAHs --- p.68 / Chapter 2.5.1 --- Experimental design --- p.68 / Chapter 2.5.1.1 --- Pretreatment and incubation --- p.68 / Chapter 2.5.1.2 --- Extraction of sorbed PAHs in soil system or in SMC --- p.69 / Chapter 2.5.1.3 --- Extraction of PAHs in water system --- p.70 / Chapter 2.5.1.4 --- Putative identification and quantification of PAHs --- p.71 / Chapter 2.5.2 --- Assessment criteria --- p.72 / Chapter 2.5.3 --- Stability of PAHs --- p.77 / Chapter 2.5.4 --- Optimization for removal of PAHs --- p.78 / Chapter 2.5.4.1 --- Effects of initial PAH concentration and amount of SMC --- p.78 / Chapter 2.5.4.2 --- Effect of initial pH --- p.79 / Chapter 2.5.4.3 --- Effect of incubation time --- p.79 / Chapter 2.5.4.4 --- Effect of incubation temperature --- p.79 / Chapter 2.5.5 --- Putative identification of intermediates and/or breakdown products --- p.80 / Chapter 2.5.6 --- Isotherm plots and fitting into monolayer models --- p.80 / Chapter 2.5.6.1 --- Langmuir isotherm --- p.80 / Chapter 2.5.6.2 --- Freundlich isotherm --- p.81 / Chapter 2.5.7 --- Toxicological study of Microtox® test --- p.82 / Chapter 2.5.8 --- Removal ability of SMC towards PAHs in single and in a mixture --- p.82 / Chapter 2.5.9 --- Removal abilities of different sorbents towards PAHs in water --- p.83 / Chapter 2.5.10 --- Removal abilities of raw and autoclaved SMC towards PAHs in water --- p.83 / Chapter 2.5.11 --- Statistical validation --- p.83 / Chapter 3 --- Results --- p.85 / Chapter 3.1 --- Characterization of soil --- p.85 / Chapter 3.1.1 --- Physical and chemical properties of soil --- p.85 / Chapter 3.1.2 --- GC-MS analysis of soil --- p.85 / Chapter 3.2 --- Calibration curves of PAHs --- p.85 / Chapter 3.3 --- Optimization for extraction --- p.91 / Chapter 3.4 --- Stability of PAHs --- p.101 / Chapter 3.4.1 --- Soil system --- p.101 / Chapter 3.4.1.1 --- Effect of incubation time --- p.101 / Chapter 3.4.1.2 --- Effect of incubation temperature --- p.101 / Chapter 3.4.2 --- Water system --- p.103 / Chapter 3.4.2.1 --- Effect of incubation time --- p.103 / Chapter 3.4.2.2 --- Effect of incubation temperature --- p.103 / Chapter 3.5 --- Characterization of SMC --- p.103 / Chapter 3.5.1 --- Physical and chemical properties of SMC --- p.103 / Chapter 3.5.2 --- GC-MS analysis of SMC --- p.106 / Chapter 3.5.3 --- Infrared spectroscopic study and chitin content --- p.106 / Chapter 3.5.4 --- Removal abilities of different sorbents towards PAHs in water --- p.121 / Chapter 3.5.5 --- Removal abilities of raw and autoclaved SMC towards PAHs in water --- p.121 / Chapter 3.6 --- Optimization for removal of PAHs --- p.124 / Chapter 3.6.1 --- Naphthalene --- p.124 / Chapter 3.6.1.1 --- Soil system --- p.124 / Chapter 3.6.1.1.1 --- Effects of initial naphthalene concentration and amount of straw SMC on removal efficiency --- p.124 / Chapter 3.6.1.1.2 --- Effects of initial naphthalene concentration and amount of straw SMC on removal capacity --- p.128 / Chapter 3.6.1.1.3 --- Effect of initial pH --- p.128 / Chapter 3.6.1.1.4 --- Effect of incubation time --- p.128 / Chapter 3.6.1.1.5 --- Effect of incubation temperature --- p.131 / Chapter 3.6.1.1.6 --- Putative identification of intermediates and/or breakdown products --- p.131 / Chapter 3.6.1.2 --- Water system --- p.134 / Chapter 3.6.1.2.1 --- Effects of initial naphthalene concentration and amount of straw SMC on removal efficiency --- p.134 / Chapter 3.6.1.2.2 --- Effects of initial naphthalene concentration and amount of straw SMC on removal capacity --- p.137 / Chapter 3.6.1.2.3 --- Effect of initial pH --- p.137 / Chapter 3.6.1.2.4 --- Effect of incubation time --- p.139 / Chapter 3.6.1.2.5 --- Effect of incubation temperature --- p.139 / Chapter 3.6.1.2.6 --- Putative identification of intermediates and/or breakdown products --- p.143 / Chapter 3.6.2 --- Phenanthrene --- p.145 / Chapter 3.6.2.1 --- Soil system --- p.145 / Chapter 3.6.2.1.1 --- Effects of initial phenanthrene concentration and amount of straw SMC on removal efficiency --- p.145 / Chapter 3.6.2.1.2 --- Effects of initial phenanthrene concentration and amount of straw SMC on removal capacity --- p.145 / Chapter 3.6.2.1.3 --- Effect of initial pH --- p.148 / Chapter 3.6.2.1.4 --- Effect of incubation time --- p.148 / Chapter 3.6.2.1.5 --- Effect of incubation temperature --- p.151 / Chapter 3.6.2.1.6 --- Putative identification of intermediates and/or breakdown products --- p.151 / Chapter 3.6.2.2 --- Water system --- p.155 / Chapter 3.6.2.2.1 --- Effects of initial phenanthrene concentration and amount of straw SMC on removal efficiency --- p.155 / Chapter 3.6.2.2.2 --- Effects of initial phenanthrene concentration and amount of straw SMC on removal capacity --- p.155 / Chapter 3.6.2.2.3 --- Effect of initial pH --- p.157 / Chapter 3.6.2.2.4 --- Effect of incubation time --- p.157 / Chapter 3.6.2.2.5 --- Effect of incubation temperature --- p.161 / Chapter 3.6.2.2.6 --- Putative identification of intermediates and/or breakdown products --- p.163 / Chapter 3.6.3 --- Benzo[a]pyrene --- p.163 / Chapter 3.6.3.1 --- Soil system --- p.163 / Chapter 3.6.3.1.1 --- Effects of initial benzo[a]pyrene concentration and amount of straw SMC on removal efficiency --- p.163 / Chapter 3.6.3.1.2 --- Effects of initial benzo[a]pyrene concentration and amount of straw SMC on removal capacity --- p.167 / Chapter 3.6.3.1.3 --- Effect of initial pH --- p.167 / Chapter 3.6.3.1.4 --- Effect of incubation time --- p.168 / Chapter 3.6.3.1.5 --- Effect of incubation temperature --- p.168 / Chapter 3.6.3.1.6 --- Putative identification of intermediates and/or breakdown products --- p.172 / Chapter 3.6.3.2 --- Water system --- p.172 / Chapter 3.6.3.2.1 --- Effects of initial benzo[a]pyrene concentration and amount of straw SMC on removal efficiency --- p.172 / Chapter 3.6.3.2.2 --- Effects of initial benzo[a]pyrene concentration and amount of straw SMC on removal capacity --- p.176 / Chapter 3.6.3.2.3 --- Effect of initial pH --- p.178 / Chapter 3.6.3.2.4 --- Effect of incubation time --- p.178 / Chapter 3.6.3.2.5 --- Effect of incubation temperature --- p.181 / Chapter 3.6.3.2.6 --- Putative identification of intermediates and/or breakdown products --- p.183 / Chapter 3.6.4 --- "Benzo[g,h,i]perylene" --- p.183 / Chapter 3.6.4.1 --- Soil system --- p.183 / Chapter 3.6.4.1.1 --- "Effects of initial benzo[g,h,i]perylene concentration and amount of straw SMC on removal efficiency" --- p.183 / Chapter 3.6.4.1.2 --- "Effects of initial benzo[g,h,i]perylene concentration and amount of straw SMC on removal capacity" --- p.187 / Chapter 3.6.4.1.3 --- Effect of initial pH --- p.187 / Chapter 3.6.4.1.4 --- Effect of incubation time --- p.187 / Chapter 3.6.4.1.5 --- Effect of incubation temperature --- p.189 / Chapter 3.6.4.1.6 --- Putative identification of intermediates and/or breakdown products --- p.189 / Chapter 3.6.4.2 --- Water system --- p.192 / Chapter 3.6.4.2.1 --- "Effects of initial benzo[g,h,i]perylene concentration and amount of straw SMC on removal efficiency" --- p.192 / Chapter 3.6.4.2.2 --- "Effects of initial benzo[g,h,i]perylene concentration and amount of straw SMC on removal capacity" --- p.196 / Chapter 3.6.4.2.3 --- Effect of initial pH --- p.198 / Chapter 3.6.4.2.4 --- Effect of incubation time --- p.198 / Chapter 3.6.4.2.5 --- Effect of incubation temperature --- p.198 / Chapter 3.6.4.2.6 --- Putative identification of intermediates and/or breakdown products --- p.201 / Chapter 3.7 --- Isotherm plots and fitting into monolayer models --- p.205 / Chapter 3.7.1 --- Sorption of naphthalene --- p.205 / Chapter 3.7.2 --- Sorption of phenanthrene --- p.205 / Chapter 3.7.3 --- Sorption of benzo[a]pyrene --- p.208 / Chapter 3.7.4 --- "Sorption of benzo[g,h,i]perylene" --- p.208 / Chapter 3.8 --- Toxicological study of Microtox test --- p.208 / Chapter 3.8.1 --- Soil system --- p.214 / Chapter 3.8.2 --- Water system --- p.214 / Chapter 3.9 --- Operable conditions of SMC for removal of PAHs --- p.214 / Chapter 3.10 --- Removal ability of SMC towards PAHs in single and in a mixture --- p.214 / Chapter 3.10.1 --- Soil system --- p.216 / Chapter 3.10.2 --- Water system --- p.216 / Chapter 4 --- Discussion --- p.221 / Chapter 4.1 --- Characterization of SMC --- p.221 / Chapter 4.2 --- Removal abilities of different sorbents towards PAHs in water --- p.223 / Chapter 4.3 --- Removal abilities of raw and autoclaved SMC towards PAHs in water --- p.226 / Chapter 4.4 --- Extraction efficiencies of PAHs --- p.227 / Chapter 4.5 --- Factors affecting removal of PAHs by SMC --- p.229 / Chapter 4.5.1 --- Initial PAH concentration and amount of straw SMC --- p.229 / Chapter 4.5.2 --- Initial pH --- p.237 / Chapter 4.5.3 --- Incubation time --- p.237 / Chapter 4.5.4 --- Incubation temperature --- p.242 / Chapter 4.6 --- Putative identification of intermediates and/or breakdown products --- p.247 / Chapter 4.7 --- Isotherm plots and fitting into monolayer models --- p.257 / Chapter 4.8 --- Toxicological study of Microtox® test --- p.258 / Chapter 4.9 --- Removal ability of SMC towards PAHs in single and in a mixture --- p.261 / Chapter 4.10 --- Comparison of removal efficiencies of benzo[a]pyrene by layering and mixing of straw SMC with soil --- p.265 / Chapter 4.11 --- Comparison of removal efficiencies of benzo[a]pyrene in different scales of experiment setup --- p.267 / Chapter 4.12 --- Effect of age of straw SMC on removal of PAHs --- p.270 / Chapter 4.13 --- Removal of benzo[a]pyrene by an aqueous extract of SMC --- p.270 / Chapter 4.14 --- Advantages of using SMC in removal of PAHs --- p.273 / Chapter 4.15 --- Limitations of the study --- p.278 / Chapter 4.16 --- Further investigation --- p.280 / Chapter 5 --- Summary --- p.282 / Chapter 6 --- Conclusion --- p.285 / Chapter 7 --- References --- p.286
197

An Assessment of Fluorometric Techniques for Tracking the Transport of Polycyclic Aromatic Hydrocarbons from Groundwater into Surface Water Bodies

Seyitmuhammedov, Kyyas 27 July 2014 (has links)
"A number of fluorometric techniques have been applied to characterize contamination associated with oil discharges and spills in the environment. While these techniques provide quick and lower cost alternatives to the many of the advanced techniques for characterizing oil-related constituents, their applicability still isn’t fully understood. The objectives of this research were to understand the characteristics of organic transport in a linked surface-water/ground-water system, and develop some practical approaches using fluorometry to characterize the pathways of organic transport. The approach included modeling, field sampling and comparisons of laboratory analyses to assess basic field fluorometry techniques for characterizing sources and distributions of polycyclic aromatic hydrocarbons (PAHs) associated with oil discharges. The primary field site included a canal and nearby river, which resulted in generally uniform hydraulic gradient, such that petroleum and PAH contamination at the site could be characterized. Historical data provided general information on the distribution of contamination. Modeling using the Modflow groundwater flow package provided basic information on groundwater flow pathways and rates. Samples were collected from the canal, groundwater, the river and a treatment facility. Additional samples were collected from Bayou Corne sinkhole in Lousiana and the Deepwater Horizon crude oil spill in the Gulf of Mexico. The samples were analyzed for fluorometric absorbance using a 10AU field fluorometer, a Shimadzu absorbance spectrometer and a LS5 luminescence spectrometer (which provided fluorescence over a spectrum of frequencies). Additional analyses were completed using a gas chromatograph with a flame ionization detector (GC-FID) to provide a more complete qualitative description of the oil composition. Analysis of the results from the 10-AU field fluorometer confirmed the capability of the field fluorometer to detect organic contamination resulting from crude and refined oil spills. Absorbance spectrometer results demonstrated possibility of using the PAH absorbance spectra to distinguish between the different types of oil, although more detailed analyses using various types of oil is recommended. The results using the luminescence spectrometer were consistent with GC FID results, and provided useful comparisons indicating the characteristics of fresh and weathered oil. The comparisons provide insight into the applicability of fluorometric approaches for characterizing transport pathways and concentrations of organic constituents associated with discharges of oil and other PAHs."
198

Physico-chemical speciation and ocean fluxes of Polycyclic Aromatic Hydrocarbons

Gustafsson, Örjan January 1997 (has links)
Thesis (Ph. D.)--Joint Program in Oceanography, Massachusetts Institute of Technology/Woods Hole Oceanographic Institution, 1997. / Includes bibliographical references. / by Örjan Gustafsson. / Ph.D.
199

Spectroscopie des transitions électroniques des cations hydrocarbures aromatiques polycycliques et de leurs agrégats / Electronic Spectroscopy of Polycyclic Aromatic Hydrocarbon Cations and their Clusters

Friha, Hela 18 December 2012 (has links)
Ce travail est une étude expérimentale de la spectroscopie électronique des cations hydrocarbures aromatiques polycycliques (PAH) et de leurs agrégats dans des conditions simulant celles régnant dans le milieu interstellaire, froids et totalement isolés. L’objectif principal est d’obtenir des spectres au laboratoire qui puissent être comparés aux spetres des Bandes Diffuses Interstellaires et d’explorer les propriétés des agrégats de PAH. / This work is mainly an experimental study of the electronic spectroscopy of the polycyclic aromatic hydrocarbon cations and their clusters in conditions close to those of the interstellar medium. The aim of this study is to obtain data that can be compared with the spectrum of the diffuse interstellar bands and to explore the properties of PAH clusters.
200

Anaerobic co-digestion of food and algal waste resources

Cogan, Miriam Lucy January 2018 (has links)
Anaerobic digestion is a key energy and resource recovery technology. This work investigated potential organic waste resources to co-digest with household food waste (HFW) to stabilise the process and future-proof feedstock availability. This included novel feedstock macroalgae (seaweed) waste (SW). Hydrothermal (autoclave) pretreatment was also investigated to optimise energy recovery from HFW and SW. Preliminary experiments investigated the behaviour of HFW co-digested with either a green waste (GW) or paper waste (PW), using a batch-test laboratory scale and systematic approach with a revised waste mixture preparation method. Following preliminary trials, the co-digestion of HFW/SW was investigated using an air-dried SW mixture. Batch experiments to determine the biomethane potential (BMP) at different ratios of HFW to SW were set up. Co-digesting HFW and SW at ratio 90:10 (d.w.) achieved a BMP similar to HFW alone (252±13 and 251±1 cm3 g-1 VS, respectively), and a peak methane yield for HFW:SW (90:10) at day 12 of 69±3% compared to a peak methane yield for HFW at day 19 of 70±3%. Addition of SW optimised the C/N ratio, increased concentrations of essential micronutrients and produced an overall increase in reaction kinetics. Concentrations of SW ≥25%, associated with high sulphur levels, reduced final methane productivity. Analysis of the macroalgae strains L. digitata, U. lactuca and F. serratus from the SW mixture was carried out to compare mono-digestion and co-digestion with HFW at a 90:10 ratio and the effect of autoclave pretreatment at 136°C. Co-digestion had a positive impact on methane yields for U. lactuca and F. serratus, whilst autoclave pretreatment had no significant impact on the SW strains When results were modelled for a 320 m3 anaerobic digester treating 8m3 feed per day the theoretical energy balance showed that optimal energy production from pretreated HFW at 8.09 GJ/day respectively could be achieved. To verify the suitability of using macroalgae, known to readily uptake polycyclic aromatic hydrocarbons (PAH), toxicity tests were used to determine the impact of phenanthrene sorbed by U. lactuca on the AD process. Despite U. lactuca’s ability to biosorb phenanthrene in under 2 hours, no impact on the AD process was observed. Overall, results of this study demonstrated that co-digestion of HFW and SW, at batch laboratory scale, provide a viable and sustainable waste revalorisation solution. In addition, low temperature autoclave pretreatment increased methane production (p=0.002) from the AD of HFW.

Page generated in 0.0758 seconds