A Pulse Detonation Engine (PDE) is a propulsion device that takes advantage of the pressure rise inherent to the efficient burning of fuel-air mixtures via detonations. Detonation initiation is a critical process that occurs in the cycle of a PDE. A practical method of detonation initiation is Deflagration-to-Detonation Transition (DDT), which describes the transition of a subsonic deflagration, created using low initiation energies, to a supersonic detonation. This thesis presents the effects of obstacle spacing, blockage ratio, DDT section length, and airflow on DDT behavior in hydrogen-air and ethylene-air mixtures for a repeating PDE. These experiments were performed on a 2 diameter, 40 long, continuous-flow PDE located at the General Electric Global Research Center in Niskayuna, New York. A fundamental study of experiments performed on a modular orifice plate DDT geometry revealed that all three factors tested (obstacle blockage ratio, length of DDT section, and spacing between obstacles) have a statistically significant effect on flame acceleration. All of the interactions between the factors, except for the interaction of the blockage ratio with the spacing between obstacles, were also significant. To better capture the non-linearity of the DDT process, further studies were performed using a clear detonation chamber and a high-speed digital camera to track the flame chemiluminescence as it progressed through the PDE. Results show that the presence of excess obstacles, past what is minimally required to transition the flame to detonation, hinders the length and time to transition to detonation. Other key findings show that increasing the mass flow-rate of air through the PDE significantly reduces the run-up time of DDT, while having minimal effect on run-up distance. These experimental results provided validation runs for computational studies. In some cases as little as 20% difference was seen. The minimum DDT length for 0.15 lb/s hydrogen-air studies was 8 L/D from the spark location, while for ethylene it was 16 L/D. It was also observed that increasing the airflow rate through the tube from 0.1 to 0.3 lbs/sec decreased the time required for DDT by 26%, from 3.9 ms to 2.9 ms.

Multiple myeloma is a painful and uncurable malignant disease with an increasing incidence and mortality in several countries, e.g., Sweden. Some factors are suspected to be of aetiological significance, such as ionising radiation and chronic antigenic stimulation in certain inflammatory diseases. A familial factor has also been indicated. Furthermore, some studies have demonstrated farming as an occupation entailing an increased risk for the disease. The aim of this investigation was to further elucidate the impact of different aetiological factors in relation to multiple myeloma. The knowledge of aetiology is always a prerequisite for prevention. A case-control study on multiple myeloma was performed in a high-inddence area, the northern part of Sweden. One part of this study dealt with occupations and different exposures. The results supported farming as being an occupation with an increased risk. Within farming two kinds of pesticides, phenoxyacetic adds and DDT, and contact with certain domestic animals, i.e., cattle, horses and goats, were assodated with multiple myeloma. Farming as a risk factor was also confirmed by a register-based linkage study using the Swedish Cancer Environment Register. In this study a time trend was indicated, with increasing standardized inddence ratios over the different time periods studied. Another part of the case-control study showed that rheumatoid arthritis entailed an increased risk for multiple myeloma, a finding earlier suggested from register-based linkage studies, but not from any çase-control study. A third part of the case-control study indicated an increased risk for multiple myeloma if any first-degree relative had a history of haematological malignancy, or other malignant tumour, espedally prostatic cancer, brain tumour, and renal cancer. A case study encompassing 942 patients with haematological malignandes in the county of Jämtland, Sweden, during a 22-year period showed that about 5% of the patients had at least one relative who also suffered from such a disease. An espedally strong familial occurrence was found in the group of chronic lymphoprohferative diseases, including multiple myeloma. / <p>S. 1-69: sammanfattning, s. 71-129: 5 uppsatser</p> / digitalisering@umu

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv., 2003. / Härtill 4 uppsatser.

Thesis (MSc. (Human Physiology, Faculty of Health Sciences))--University of Pretoria, 2008. / Includes bibliographical references.

The object of this thesis is the assessment of fish contamination by selected foreign substances as toxic metals, polychlorinated biphenyls and pesticides in 31 selected fishing grounds. The monitoring was realized between years 2006 and 2010. Fish were caught by electric device and fishing rods. Concentrations of Hg, Cd, Pb, PCB, DDT, HCH and HCB in fish muscle tissues were monitored. Common bream (Abramis brama) was selected as a reference species for a comparison of the monitored sites. The results of analysis were compared with valid hygienic limits. Overrun of hygienic limit for some of the monitored pollutants were observed in 18 localities. We found mercury as a major pollutant in the aquatic environment.

Made available in DSpace on 2014-06-11T19:22:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-03-07Bitstream added on 2014-06-13T19:27:38Z : No. of bitstreams: 1 souza_jp_me_jabo.pdf: 1313453 bytes, checksum: 4c61c83068fdecf5e8c6a9ee5b5f525e (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O inseticida diflubenzuron (DFB), comercializado como Dimilin®, é empregado em pisciculturas no tratamento de ecotoparasitoses em peixes. Este composto inibe a síntese de quitina, componente do exoesqueleto dos parasitas. A utilização deste inseticida se deve à sua baixa toxicidade aos peixes e eficácia no controle dos ectoparasitas. Porém, no ambiente aquático o DFB pode ser tóxico à espécies sensíveis e não-alvos, a concentração empregada no tratamento das ectoparasitoses é de 2 mg.L-1. Os objetivos deste estudo foram avaliar a toxicidade do DFB para as espécies de Daphnia magna, Poecilia reticulata e Lemna minor, classificar o produto quanto à sua toxicidade e risco ambiental e avaliar o efeito do sedimento na biodisponibilidade do DFB na água. Os organismos-teste foram submetidos a concentrações crescentes do inseticida em salas climatizadas do Laboratório de Ecotoxicologia da FCAV-UNESP. Os testes com D. magna foram realizados em volume de 10 mL a 20° C e cinco organismos neonatos por concentração, durante 48 horas na presença e ausência de sedimento. Os peixes (P. reticulata) foram expostos às concentrações do DFB por 96 horas em testes na presença e ausência de sedimento. O volume final foi de 3000 mL e cinco animais por concentração à 25° C. As plantas de L. minor foram expostas ao DFB por sete dias na presença e ausência de sedimento. O volume final foi de 100 mL e 12 frondes por concentração à 24° C. Os testes foram realizados com três réplicas incluindo o controle. As CE50-48h calculadas para D. magna foram de 0,56 μg.L-1 e 1,51 μg.L-1 na ausência e presença de sedimento respectivamente; as CL50-96h para P. reticulata foram 152,00 mg.L-1 e 277,83 mg.L-1 na ausência e presença de sedimento respectivamente; e as CE50-7dias para L. minor foram 459,50 mg.L-1 e 698,25 mg.L-1 na ausência e presença de sedimento respectivamente... / The insecticide diflubenzuron (DFB), marketed as Dimilin®, is used in fish farms to treat ectoparasites in fishes. This compound inhibits the chitin synthesis, exoskeleton component of the parasites. The use of this insecticide is due to its low toxicity for fish and effectiveness in the control of ectoparasites. However, the DFB in the aquatic environmental can be toxic to sensitive species and non-targed, the concentration used in the treatment of ectoparasites is 2 mg.L-1. The aims of this study were to evaluate the toxicity of the DFB for the species of Daphnia magna, Poecilia reticulata and Lemna minor, classify the product as to their toxicity and environmental risk and evaluate the effect of sediment on the bioavailability of the DFB in the water. The organisms-test were submitted to increasing concentrations of insecticide in air conditioned rooms of the Laboratory of Ecotoxicology FCAV-UNESP. Tests with D. magna were performed in volume of 10 mL at 20° C and five organisms neonates (6 and 24 hours of age) in each concentration, for 48 hours in the presence and absence of sediment. Fishes (P. reticulata) were exposed to concentrations of the DFB for 96 hours in tests in the presence and absence of sediment. The final volume was 3000 mL and five animals per concentration to 25° C. The plants of L. minor were exposed to the DFB for seven days in the presence and absence of sediment. The final volume was 100 mL and 12 fronds by concentration to 24° C. The tests were performed with three repetitions incluing the control. The EC50-48h estimeds for D. magna were 0.56 and 1.51 μg.L-1 in the absence and presence of sediment respectively; the LC50-96h for P. reticulata were 152.00 mg.L-1 and 277.83 mg.L-1 in the absence and presence of sediment respectively; and the EC50-7dias to L. minor were 459.50 mg.L-1 and 698.25 mg.L-1 in the absence and presence of sediment respectively...(Complete abstract, click electronic access below)

Made available in DSpace on 2014-06-11T19:22:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-04-22Bitstream added on 2014-06-13T20:28:40Z : No. of bitstreams: 1 medeiros_ls_me_jabo.pdf: 334435 bytes, checksum: 9100b99eed78123f4f48b7158f17a02f (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os agrotóxicos aplicados nas áreas agrícolas podem ser carreados, por diversos mecanismos, até os corpos d’água da rede hidrográfica. Além disso, estes produtos são comumente utilizados na aqüicultura para o controle de parasitoses. O teflubenzuron (TFB) é um inseticida registrado em alguns países da Europa para o controle de parasitas de peixes. Os possíveis efeitos tóxicos e risco ambiental do TFB podem ser avaliados inicialmente em condições de laboratório por meio de testes de toxicidade aguda com organismos-teste eleitos internacionalmente. Os objetivos deste trabalho foram avaliar a toxicidade aguda e o risco de intoxicação ambiental do uso agrícola e em aqüicultura do TFB, com base nos valores de CE50 e CL50 estimados em testes com Daphnia magna, Lemna minor e Poecilia reticulata, utilizados como organismos bioindicadores. Os testes de ecotoxicidade aguda foram realizados de acordo com normas nacionais e internacionais para estas espécies. A CE50-48h estimada para D. magna foi 0,00026 mg.L- 1, o que caracteriza este inseticida como altamente tóxico para esta espécie. Para L. minor, a CE50-7d estimada foi 1.176,16 mg.L-1, e para P. reticulata CL50-96h, 2.707,87 mg.L- 1, que classificam o TFB como praticamente não-tóxico para estas duas espécies. Devido à alta toxicidade do TFB para daphnídeos, mesmo em pequenas contaminações, pode causar desequilíbrio na cadeia alimentar aquática. Para minimizar o risco ambiental, o TFB pode ser utilizado de forma controlada e diluído em quantidades restritas de água. / The pesticides used in agriculture areas can be transported to water bodies of the local hydrographic basin in several ways. Moreover, these chemicals are commonly used in aquaculture to fish parasite control. The teflubenzuron (TFB) is a registered insecticide in some European countries to this use. The possible effects of the TFB and environmental risk can be evaluated initially in laboratory conditions by tests of acute toxicity with internationally elected organisms. The objectives of this study were to evaluate the acute toxicity and the environmental risk due to agriculture and aquaculture use of TFB, based on the values of EC50 and LC50 estimated in tests with Daphnia magna, Lemna minor and Poecilia reticulata, internationally used as bioindicators organisms. The acute ecotoxicity tests were performed in accordance with national and international standards for these species. The EC50-48h estimated to D. magna was 0,00026 mg.L-1, which characterizes that as very highly toxic insecticide for this species. For L. minor, EC50-7d was estimated 1.176,16 mg.L-1, and P. reticulata LC50-96h, 2.707,87 mg.L-1, which classified the TFB as practically non-toxic to these species. Due to the high toxicity of the TFB to daphnids, even in little contamination, can cause a loss of equilibrium in the aquatic food chain. To minimize the environmental risk, the TFB can be used in a controlled way and diluted in limited quantities of water.

Orientador: Joaquim Gonçalves Machado Neto / Banca: Julio Vicente Lombardi / Banca: Robinson Antonio Pitelli / Resumo: Os agrotóxicos aplicados nas áreas agrícolas podem ser carreados, por diversos mecanismos, até os corpos d'água da rede hidrográfica. Além disso, estes produtos são comumente utilizados na aqüicultura para o controle de parasitoses. O teflubenzuron (TFB) é um inseticida registrado em alguns países da Europa para o controle de parasitas de peixes. Os possíveis efeitos tóxicos e risco ambiental do TFB podem ser avaliados inicialmente em condições de laboratório por meio de testes de toxicidade aguda com organismos-teste eleitos internacionalmente. Os objetivos deste trabalho foram avaliar a toxicidade aguda e o risco de intoxicação ambiental do uso agrícola e em aqüicultura do TFB, com base nos valores de CE50 e CL50 estimados em testes com Daphnia magna, Lemna minor e Poecilia reticulata, utilizados como organismos bioindicadores. Os testes de ecotoxicidade aguda foram realizados de acordo com normas nacionais e internacionais para estas espécies. A CE50-48h estimada para D. magna foi 0,00026 mg.L- 1, o que caracteriza este inseticida como altamente tóxico para esta espécie. Para L. minor, a CE50-7d estimada foi 1.176,16 mg.L-1, e para P. reticulata CL50-96h, 2.707,87 mg.L- 1, que classificam o TFB como praticamente não-tóxico para estas duas espécies. Devido à alta toxicidade do TFB para daphnídeos, mesmo em pequenas contaminações, pode causar desequilíbrio na cadeia alimentar aquática. Para minimizar o risco ambiental, o TFB pode ser utilizado de forma controlada e diluído em quantidades restritas de água. / Abstract: The pesticides used in agriculture areas can be transported to water bodies of the local hydrographic basin in several ways. Moreover, these chemicals are commonly used in aquaculture to fish parasite control. The teflubenzuron (TFB) is a registered insecticide in some European countries to this use. The possible effects of the TFB and environmental risk can be evaluated initially in laboratory conditions by tests of acute toxicity with internationally elected organisms. The objectives of this study were to evaluate the acute toxicity and the environmental risk due to agriculture and aquaculture use of TFB, based on the values of EC50 and LC50 estimated in tests with Daphnia magna, Lemna minor and Poecilia reticulata, internationally used as bioindicators organisms. The acute ecotoxicity tests were performed in accordance with national and international standards for these species. The EC50-48h estimated to D. magna was 0,00026 mg.L-1, which characterizes that as very highly toxic insecticide for this species. For L. minor, EC50-7d was estimated 1.176,16 mg.L-1, and P. reticulata LC50-96h, 2.707,87 mg.L-1, which classified the TFB as practically non-toxic to these species. Due to the high toxicity of the TFB to daphnids, even in little contamination, can cause a loss of equilibrium in the aquatic food chain. To minimize the environmental risk, the TFB can be used in a controlled way and diluted in limited quantities of water. / Mestre

Submitted by Isaac Francisco de Souza Dias (isaac.souzadias@ufpe.br) on 2016-06-08T19:08:39Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Daniele Miranda (Dissertação) (1).pdf: 2212174 bytes, checksum: 072adb47d6f470af0ef00119e299bcf8 (MD5) / Made available in DSpace on 2016-06-08T19:08:39Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Daniele Miranda (Dissertação) (1).pdf: 2212174 bytes, checksum: 072adb47d6f470af0ef00119e299bcf8 (MD5) Previous issue date: 2015-08-26 / CNPQ / Poluentes orgânicos persistentes (POPs) são ubíquos no ambiente global devido a grande estabilidade química e ampla dispersão. As características lipofílicas destes compostos favorecem a sua acumulação em peixes. Tais compostos estão associados ao desenvolvimento de câncer e desregulação do sistema endócrino. Apesar das proibições e restrições atribuídas a estes compostos, eles são frequentemente detectados no ambiente e a população humana está exposta a esta classe de contaminantes, principalmente, através do consumo de alimentos contaminados, como o pescado. O presente estudo teve como objetivos: (1) implementar metodologia para análise de PCBs e pesticidas organoclorados (DDTs, HCHs, clordanos, heptacloro e mirex) em peixe; (2) verificar a ocorrência de tais compostos em Scomberomorus cavalla; (3) investigar possíveis correlações entre os níveis de contaminantes e os parâmetros biológicos da espécie (idade, sexo, estágio de maturação e percentual de lipídios); e (4) estimar a exposição da população humana local a PCBs e DDTs através do consumo S. cavalla. Amostras de músculo e fígado foram separadas de 20 peixes adquiridos em colônias de pesca de Recife e região metropolitana. O método de extração foi Soxhlet (8 h), seguido por purificação com tratamento ácido. O extrato final foi analisado através de cromatografia em fase gasosa acoplada a espectrometria de massas (GC-MS). A metodologia para análise de organoclorados foi implementada e avaliada através de material de referência certificado. O limite de quantificação do método foi em média 0,50 ng g-1 peso seco (ps). PCBs e DDTs foram os grupos de compostos detectados em maiores concentrações nos espécimes estudados. As concentrações de PCBs, DDTs e clordanos no músculo variaram de 2,88 a 97,4 ng g-1 ps, 0,92 a 11,6 ng g-1 ps e nd (não detectado) a 2,11 ng g-1 ps, respectivamente. No fígado as concentrações desses contaminantes variaram de 47,5 a 267 ng g-1 ps, 7,95 a 34,8 ng g-1 ps e nd a 5,52 ng g-1 ps, respectivamente. HCHs, heptacloro e mirex não foram detectados nas amostras. Os parâmetros biológicos de S. cavalla não apresentaram correlação com as concentrações dos compostos estudados. A estimativa de ingestão diária de PCBs e DDTs pela população pernambucana mostrou que a cavala é uma espécie segura para consumo, segundo limites de referência propostos por agências da Organização das Nações Unidas (ONU). / Persistent organic pollutants (POPs) are ubiquitous worldwide due to high chemical stability and long-range atmospheric transport. Their lipophilic properties facilitate accumulation in fish tissues. POPs have been associated with development of cancer and endocrine disruption in vertebrates. Despite the ban in most countries, they are still detected in the environment. Human populations are exposed to POPs mainly through consumption of contaminated food including fish. The aim of this study is four-fold: (1) to optimize a laboratory method for analyzing polychlorinated biphenyls (PCBs) and chlorinated pesticides (DDTs, HCHs, chlordane, heptachlor and mirex) in fish tissues; (2) to investigate the occurrence of chlorinated compounds in king mackerel (Scomberomorus cavalla); (3) to assess potential correlations between contaminant levels and biological parameters of king mackerel; and (4) to estimate exposure of local human populations to PCBs and DDTs through consumption of king mackerel. A total of 20 fishes were purchased from artisanal fishermen at Recife and metropolitan area, northeastern Brazil. Muscle and liver tissues were selected for analysis. Samples were Soxhlet-extracted for 8 h and cleaned up with concentrated sulfuric acid. The extracts were injected into a gas chromatography-mass spectrometry system (GC-MS). The laboratory method was validated with certified reference material. The average limit of quantitation was 0.50 ng g-1 dry weight (dw). PCBs and DDTs were the major contaminants found in the samples while HCHs, heptachlor and mirex were not detected. Concentrations of PCBs, DDTs and chlordane-related compounds in muscle ranged from 2.88 to 97.4 ng g-1 dw, 0.92 to 11.6 ng g-1 dw, and nd (not detected) to 2.11 ng g-1 dw, respectively. Concentrations of the same contaminants in liver ranged from 47.5 to 267 ng g-1 dw, 7.95 to 34.8 ng g-1 dw, and nd to 5.52 ng g-1 dw, respectively. Biological parameters of S. cavalla were not significantly correlated with contaminant levels. The local population estimated daily intake of PCBs and DDTs through fish consumption revealed that S. cavalla is a safe food. Such a conclusion is based on reference limits established by the United Nations (UN) specialized agencies.

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