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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.
111

NOx and CO formation for lean-premixed methane-air combustion in a jet-stirred reactor operated at elevated pressure /

Rutar Shuman, Teodora. January 2000 (has links)
Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (leaves 178-184).
112

Índice biespectral, variáveis intracranianas e cardiovasculares em cães anestesiados com diferentes doses de infusão de propofol, associados ou não ao óxido nitroso /

Duque, Celina Tie Nishimori. January 2006 (has links)
Orientador: Newton Nunes / Banca: Almir Pereira de Souza / Banca: Anderson Farias / Banca: Carlos Augusto Araújo Valadão / Banca: Paulo Sérgio Patto dos Santos / Resumo: A anestesia total intravenosa tem sido bastante empregada na neuroanestesia em humanos, geralmente para evitar o efeito vasodilatador do óxido nitroso (N20) e outros agentes voláteis. Dessa forma, este estudo determinou, em cães, os efeitos da anestesia com infusão contínua de propofol em diferentes doses, associada ou não ao N20, sobre variáveis intracranianas, cardiovasculares e índice biespectral (BIS). Foram utilizados 32 cães adultos distribuídos em quatro grupos de oito animais, denominados grupo propofol decrescente + N20 (GPDO, n=8), grupo propofol decrescente (GPD, n=8), grupo propofol crescente + N20 (GPCO, n=8) e grupo propofol crescente (GPC, n=8). Os animais foram induzidos à anestesia pela administração intravenosa de propofol (10mg/kg). Após intubação orotraqueal, o GPDO recebeu N20 a 70% e 02 a 30%. Em seguida, iniciou-se a infusão contínua de propofol na dose de 0,8mg/kg/min. A dose do anestésico foi reduzida para 0,6mg/kg/min e então para O,4mg/kg/min, respeitando um intervalo de 50 minutos entre cada uma. O mesmo protocolo foi adotado para o GPD, substituindo-se o fluxo diluente por 02 a 100%. Para GPCO e GPC, iniciou-se a infusão de propofol na dose de O,4mg/kg/min. A dose do anestésico foi acrescida para O,6mg/kg/min e depois para 0,8mg/kg/min, respeitando um intervalo de 50 minutos entre cada uma, sendo que o fluxo diluente no GPCO foi de N20 a 70% e 02 a 30%, e o GPC recebeu 02 a 100%. Os dados foram submetidos à análise de variância de uma via seguida pelo teste de Tukey (p<0,05) para detectar diferenças entre os grupos. Para comparação dos momentos ao longo do tempo utilizou-se a análise de variância de uma via para medições repetidas seguida pelo teste de Tukey (p<O,05)... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Total intravenous anesthesia has been used in neuroanesthesia as a method to avoid the cerebral vasodilating effects of nitrous oxide (N20) and volatile agents. The aim of this study was to evaluate intracranial and cardiovascular variables, and also bispectral index (BIS) in dogs submitted to continuous infusion rates of propofol combined with nitrous oxide (N20). Thirty two adult dogs were assigned into four groups composed by eight animais: group propofol decreasing + N20 (GPDO, n=8); group propofol decreasing (GPD, n=8); group propofol increasing + N20 (GPCO, n=8); and group propofol increasing (GPC, n=8). Anesthesia was induced with propofol administered intravenously (10mg/kg). After orotracheal intubation, GPDO received 70% N20 and 30% 02. Subsequently, continuous infusion of propofol was begun using a primary dose of 0.8mg/kg/min. The anesthetic dose was decreased to 0.6mg/kg/min, and then to O.4mg/kg/min, respecting an interval of 50 minutes between them. The GPD was submitted to the same protocol; however, the diluent flow was substituted by 100% 02. For GPCO and GPC, continuous infusion of propofol was begun using a primary dose of 0.4mg/kg/min. The anesthetic dose was increased to 0.6mg/kg/min, and then to 0.8mg/kg/min, respecting an interval of 50 minutes between them. The GPCO received 70% N20 and 30% O2 and GPC 100% O2. The data were submitted to One way Anova following Tukey test (p<0.05) to detect differences between groups. For comparisons between moments, one way RM Anova followed by Tukey test (p<0.05) was used. Cerebral perfusion pressure (CPP), BIS, heart rate (HR), systolic (SAP) diastolic (DAP), and mean arterial (MAP) pressures, systemic vascular resistance (SVR) and index (ISVR) diminished with the highest infusion rate in ali groups. Cardiac output (C O) and index (CI) increased using 0.6mg/kg/min dose of propofol in GPDO and GPD groups, with the highest ...(Complete abstract, click electronic access below) / Doutor
113

Índice biespectral, variáveis intracranianas e cardiovasculares em cães anestesiados com diferentes doses de infusão de propofol, associados ou não ao óxido nitroso

Duque, Celina Tie Nishimori [UNESP] 01 December 2006 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:32:51Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-12-01Bitstream added on 2014-06-13T19:43:38Z : No. of bitstreams: 1 duque_ctn_dr_jabo.pdf: 940048 bytes, checksum: 7cf59ce6ead86a57d64eaccbc29434ce (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A anestesia total intravenosa tem sido bastante empregada na neuroanestesia em humanos, geralmente para evitar o efeito vasodilatador do óxido nitroso (N20) e outros agentes voláteis. Dessa forma, este estudo determinou, em cães, os efeitos da anestesia com infusão contínua de propofol em diferentes doses, associada ou não ao N20, sobre variáveis intracranianas, cardiovasculares e índice biespectral (BIS). Foram utilizados 32 cães adultos distribuídos em quatro grupos de oito animais, denominados grupo propofol decrescente + N20 (GPDO, n=8), grupo propofol decrescente (GPD, n=8), grupo propofol crescente + N20 (GPCO, n=8) e grupo propofol crescente (GPC, n=8). Os animais foram induzidos à anestesia pela administração intravenosa de propofol (10mg/kg). Após intubação orotraqueal, o GPDO recebeu N20 a 70% e 02 a 30%. Em seguida, iniciou-se a infusão contínua de propofol na dose de 0,8mg/kg/min. A dose do anestésico foi reduzida para 0,6mg/kg/min e então para O,4mg/kg/min, respeitando um intervalo de 50 minutos entre cada uma. O mesmo protocolo foi adotado para o GPD, substituindo-se o fluxo diluente por 02 a 100%. Para GPCO e GPC, iniciou-se a infusão de propofol na dose de O,4mg/kg/min. A dose do anestésico foi acrescida para O,6mg/kg/min e depois para 0,8mg/kg/min, respeitando um intervalo de 50 minutos entre cada uma, sendo que o fluxo diluente no GPCO foi de N20 a 70% e 02 a 30%, e o GPC recebeu 02 a 100%. Os dados foram submetidos à análise de variância de uma via seguida pelo teste de Tukey (p<0,05) para detectar diferenças entre os grupos. Para comparação dos momentos ao longo do tempo utilizou-se a análise de variância de uma via para medições repetidas seguida pelo teste de Tukey (p<O,05)... / Total intravenous anesthesia has been used in neuroanesthesia as a method to avoid the cerebral vasodilating effects of nitrous oxide (N20) and volatile agents. The aim of this study was to evaluate intracranial and cardiovascular variables, and also bispectral index (BIS) in dogs submitted to continuous infusion rates of propofol combined with nitrous oxide (N20). Thirty two adult dogs were assigned into four groups composed by eight animais: group propofol decreasing + N20 (GPDO, n=8); group propofol decreasing (GPD, n=8); group propofol increasing + N20 (GPCO, n=8); and group propofol increasing (GPC, n=8). Anesthesia was induced with propofol administered intravenously (10mg/kg). After orotracheal intubation, GPDO received 70% N20 and 30% 02. Subsequently, continuous infusion of propofol was begun using a primary dose of 0.8mg/kg/min. The anesthetic dose was decreased to 0.6mg/kg/min, and then to O.4mg/kg/min, respecting an interval of 50 minutes between them. The GPD was submitted to the same protocol; however, the diluent flow was substituted by 100% 02. For GPCO and GPC, continuous infusion of propofol was begun using a primary dose of 0.4mg/kg/min. The anesthetic dose was increased to 0.6mg/kg/min, and then to 0.8mg/kg/min, respecting an interval of 50 minutes between them. The GPCO received 70% N20 and 30% O2 and GPC 100% O2. The data were submitted to One way Anova following Tukey test (p<0.05) to detect differences between groups. For comparisons between moments, one way RM Anova followed by Tukey test (p<0.05) was used. Cerebral perfusion pressure (CPP), BIS, heart rate (HR), systolic (SAP) diastolic (DAP), and mean arterial (MAP) pressures, systemic vascular resistance (SVR) and index (ISVR) diminished with the highest infusion rate in ali groups. Cardiac output (C O) and index (CI) increased using 0.6mg/kg/min dose of propofol in GPDO and GPD groups, with the highest ...(Complete abstract, click electronic access below)
114

Estudo de fluxo de oxido nitroso (Nsub(2)O) regional na bacia amazonica / Regional nitrous oxide flux in amazon basin

FELIPPE, MONICA T.S.D. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:27:52Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:48Z (GMT). No. of bitstreams: 0 / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
115

Estudo de fluxo de oxido nitroso (Nsub(2)O) regional na bacia amazonica / Regional nitrous oxide flux in amazon basin

FELIPPE, MONICA T.S.D. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:27:52Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:48Z (GMT). No. of bitstreams: 0 / O óxido nitroso (N2O) é o terceiro mais importante gás de efeito estufa. Globalmente, a maior fonte de N2O são os processos de nitrificação e desnitrificação no solo. Cerca de dois terços da emissão do solo ocorrem nos trópicos e aproximadamente 20% são originados nos ecossistemas de florestas tropicais úmidas, como a Floresta Amazônica. O presente estudo envolveu a realização de medidas de perfis verticais de N2O utilizando aviões de pequeno porte desde a superfície até cerca de 4 km sobre duas florestas da região leste e central da Amazônia: Flona Tapajós (2000-2009) e Rebio Cuieiras (2004-2007); e a estimativa dos fluxos de N2O da região entre a costa brasileira e as florestas acima mencionadas utilizando dois métodos de cálculo de fluxo: Método de Integração de Coluna e Modelo de Inversão FLEXPART. As medidas de N2O em escala regional até o presente momento são únicas e representam uma nova abordagem nas emissões nesta escala. Pelos dois métodos, o fluxo calculado entre a costa brasileira e a Rebio Cuieiras apresentou pouca sazonalidade e valor médio de 1,9±1,6 mgN2Om2dia1 para o Método de Integração de Coluna e 2,3±0,9 mgN2Om2dia1 para o Modelo de Inversão Flexpart. Para a região entre a costa e a Flona Tapajós, o Modelo de Inversão - FLEXPART apresentou cerca da metade (0,9±1,7 mgN2Om2dia1) do valor do fluxo de N2O calculado pelo Método de Integração de Coluna (2,0±1,1 mgN2Om2dia1) no mesmo período (2004-2008). Uma provável explicação é a não representatividade de atividades antrópicas pelo modelo de inversão, uma vez que este representou bem uma região menos impactada. As duas regiões estudadas apresentaram emissão de N2O semelhante na estação chuvosa. Pelo Método de Integração de Coluna a região entre a costa e a Flona Tapajós apresentou fluxo de N2O durante a estação seca (1,8±0,9 mgN2Om2dia1) muito próximo do fluxo calculado na estação chuvosa. Encontrou-se uma correlação entre os perfis de N2O ii e CO, traçador de queimadas, sendo esta uma das possíveis causas desta emissão. A taxa CO:N2O encontrada para os 38 perfis amostrados nesta estação foi de 82±69 mol CO:molN2O, cerca de 10 vezes maior que o apresentado em literaturas anteriores. / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
116

\"Proposta de normatização técnica para instalação e funcionamento de estabelecimentos odontológicos a utilizarem sedação consciente por analgesia inalatória através de mistura gasosa de óxido nitroso e oxigênio\" / Normative proposal to develop and prepare dental offices to perform conscious sedation using nitrous oxide and oxigen mixture

Francisco Alicio Mendes 06 November 2006 (has links)
O presente estudo objetiva mostrar ao Cirurgião Dentista, os quesitos necessários para se formar um Odontólogo apto a praticar a sedação inalatória, bem como os itens de segurança e de respaldo legal que deverão compor o seu ambiente de trabalho ao se utiliza desta técnica. O estudo foi fundamentado a partir de revisão de literatura sobre o tema, tendo como metodologia o estilo de Vancouver. A analgesia inalatória pela mistura gasosa de óxido nitroso e oxigênio constitui um excelente instrumento no controle da dor e da ansiedade dos pacientes durante o tratamento odontológico. É importante observar que a técnica de analgesia inalatória pela mistura gasosa de óxido nitroso e oxigênio deve ser realizada por meio de normatização técnica para garantir a eficiência da técnica e evitar transtornos. O roteiro proposto no trabalho visa apresentar as características de segurança e detalhamento das especificações técnicas dos estabelecimentos de assistência odontológica para o emprego da técnica de analgesia inalatória pela mistura gasosa de óxido nitroso e oxigênio. / This study has as objective to suggest a number of propositions in order to prepare and develop a dental office to perform conscious sedation by inhalatory analgesia using nitrous oxide/oxygen mixture. It was based on the revision of literature about the subject, having as methodology the Vancouver style. The conscientious sedation constitutes an excellent instrument in the control of the patient?s anxiety during dental treatment. It also will show to the Dentist the necessary requirements to the training of his personal and himself. It is important to observe that the technique itself must follow normative rules to guarantee its efficiency. The scope considered in the work aims present characteristics of security and detailed specifications to establish dental assistance for the use of conscious sedation by nitrous oxide/oxygen mixture.
117

Impacts of Bromide and Nitrogen Wastewater Discharges on Downstream Drinking Water Treatment Plant Disinfection Byproducts

Cadwallader, Adam L. 01 February 2018 (has links)
Bromide and nitrogen are wastewater effluent constituents that have raised concern for their potential to affect disinfection byproduct (DBP) formation at drinking water treatment plants (DWTPs) downstream of wastewater discharges. Despite the toxicity of brominated and nitrogenous DBPs, wastewater treatment does not usually remove bromide and nitrogen prior to discharge. Bromide is a conservative chemical and thus is not removed from surface waters via natural transformations after being released, although it may be diluted. Nitrogen is biologically reactive; it can be transformed and removed by bacteria in the environment and in wastewater treatment plants (WWTPs). While this nitrogen cycling may reduce impacts on downstream DWTPs, it also produces nitrous oxide (N2O), a greenhouse gas, as a byproduct. Thus, interaction with the environment alters the potential impact of bromide and nitrogen on drinking water systems. The objective of this work was to examine the impacts of nitrogen and bromide present in wastewater effluent on DBP formation at downstream DWTPs, within the context of current and possible future DBP regulations. Three major conclusions were reached. First, within Southwestern Pennsylvania, an area where surface water bromide concentrations have increased due to fossil fuel extraction-based wastewater discharge, no statistically significant improvement in species-specific risk was observed over the past 20 years, despite decreasing TTHM levels. Second, nitrogen treatment decisions at WWTPs influence the formation of N-nitrosodimethylamine (NDMA), an unregulated but toxic DBP, at downstream DWTPs in areas of high de facto reuse (DFR). More plants using nitrifying wastewater treatment resulted in significantly lower NDMA detection rates and concentrations observed at chloraminating DWTPs located downstream. Third, the current approach to estimating national emissions of N2O related to wastewater treatment may underestimate emissions by an order of magnitude. Further, nitrogen removal at wastewater treatment plants reduces total N2O emissions attributable to wastewater treatment by reducing the N2O that would be generated in receiving surface waters. Thus, in both cases, impacts of WWTPs on downstream DWTP DBPs were observable. While natural cycling may remove nitrogen from surface water, in-plant removal of nitrogen prevents large amounts of N2O emissions.
118

Fatores de emissões de óxidos nitrosos decorrente da aplicação de vinhaça no cultivo de cana de açúcar / Nitrous oxides emissions factors resulting from vinasse application in sugarcane cultivation

Silva, Gael Silvia da Peñaranda Liendo, 1977- 12 May 2014 (has links)
Orientador: Edson Tomaz / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-26T11:50:32Z (GMT). No. of bitstreams: 1 Silva_GaelSilviadaPenarandaLiendo_M.pdf: 1790276 bytes, checksum: 90826b2d5250dff1e3a227a40e99867c (MD5) Previous issue date: 2014 / Resumo: O Brasil é o maior produtor de cana-de-açúcar do mundo, gerando 671,71 milhões de toneladas por ano, estimados pela Companhia Nacional de Abastecimento¿ CONAB (Safra 2014/2015). É o 2º produtor mundial de etanol, sendo responsável por 20% da produção mundial e 20% das exportações mundiais, o que foi motivado pela expansão das áreas cultivadas e a maior utilização de fertilizantes, entre os quais, o emprego de fertilizantes nitrogenados para aumentar a produtividade. Atualmente, procura-se reduzir as emissões dos gases de efeito estufa (GEE) causadores do aquecimento global, o que justifica o atual esforço internacional na substituição dos combustíveis fósseis por fontes de energia limpa, como o etanol da cana-de-açúcar. Não obstante, o uso de fertilizantes (vinhaça e ureia) é necessário para a produção de etanol de cana, os quais significam aumento na emissão de GEE do sistema, especialmente do óxido nitroso. O Painel Intergovernamental de Mudanças Climáticas (IPCC, 2006) apontou que cerca de 1% do fertilizante nitrogenado utilizado em plantações seria emitida à atmosfera na forma de óxido nitroso, mas os fatores propostos parecem ser elevados para condição tropical. A realização deste trabalho teve como objetivo estimar os fatores de emissão do óxido nitroso num canavial a partir do período que vai do plantio a colheita da cultura de cana-de-açúcar, onde foram aplicados fertilizantes como a ureia e resíduos orgânicos como a vinhaça. O experimento foi instalado em cana de primeira soca, executado na fazenda Areão da ESALQ-USP, em Piracicaba ¿ SP, em delineamento em blocos ao acaso com 5 tratamentos (T1:Vinhaça in natura, T2:Vinhaça+ ureia, T3:Vinhaça concentrada, T4:Ureia e T5:Testemunha) e 6 repetições. Câmaras estáticas foram instaladas nas parcelas para monitoramento do óxido nitroso (N2O), sendo realizadas coletas de gases nas câmaras no período de dezembro de 2012 a novembro de 2013. Observou-se maiores fluxos nos 3 primeiros meses após aplicação dos tratamentos para os que receberam vinhaça e N-fertilizante. Os maiores fluxos foram associados à adição de ureia, provavelmente em função da dose de nitrogênio aplicada. No entanto, o fator de emissão do fertilizante (ureia) ficou em 0,18 %, menor do que estimado pelo IPCC. Quando a vinhaça foi aplicada junto com o fertilizante, e com grande quantidade de palha no solo, o fator de emissão chegou a 0,14%. Todavia, o uso da vinhaça concentrada mostrou-se como uma alternativa menos sustentável com um fator de emissão de 0,59 %. Observando em maior detalhe os efeitos na emissão de N2O pela aplicação da vinhaça e fertilizante nitrogenado, houve influência significativa de parâmetros do solo (NO3, C solúvel e umidade). Palavras- chave: Cana de açúcar, Fertilizante, Gás de efeito estufa, Vinhaça / Abstract: Brazil is the biggest producer of sugar cane in the world, generating 671.71 million tons per year, estimation by the National Society of Supply - CONAB (2014/2015 Harvest). The country is the 2nd biggest producer of ethanol, accounting for 20% of world production and 20% of world exports, this was driven by the expansion of cultivated areas and the increased use of fertilizers, among them, the use of nitrogen fertilizers. Currently, there are attempts to reduce emissions of greenhouse gases (GHG) that cause global warming, which explains the current international effort to replace fossil fuels by clean energy sources such as the ethanol from cane sugar. However, the use of fertilizers such as urea and vinasse is required for the production of sugar cane ethanol, which means increased GHG system emission, especially nitrous oxide. The Intergovernmental Panel on Climate Change (IPCC, 2006) found out that about 1% of the nitrogen fertilizer used in plantations is emitted to the atmosphere as nitrous oxide, but the proposed factors appear to be higher for tropical condition. This article aimed to estimate the emission factors of nitrous oxide from a cane crop, from the planting to the harvest, where urea and organic waste such as vinassewere applied. The experiment was carried out using cane first leaf, it took place at Areão farm ESALQ-USP, in Piracicaba - SP, in randomized blocks using 5 different treatments (T1: Vinasse in natura, T2: Vinasse + urea, T3: Concentrated vinasse, T4: Urea and T5: Witness) and 6 replications. Static cameras were installed in the parcels for monitoring the nitrous oxide (N2O) gas collections were held in the chambers from December 2012 to November 2013. There were greater flows in the first 3 months after the application ofvinasse and N fertilizer. The largest flows were associated with the addition of urea, probably because of the applied nitrogen rate. However, the fertilizer emission factor (urea) was 0.18%, lower than the estimated by the IPCC. When vinasse was applied with fertilizer, using a big amount of straw in the soil, the emission factor reached 0.14%. However, the use of concentrated vinasse proved to be a less sustainable alternative with a 0.59% emission factor. Observing more deeply the effects of N2O emissions, by the application of vinasse and nitrogen fertilizer, a significant influence on soil parameters was shown (NO3, C soluble and humidity). Key words: Sugarcane, fertilizer, greenhouse gas, Vinasse / Mestrado / Engenharia de Processos / Mestra em Engenharia Química
119

A Study of Detonations, DDT and Deflagrations in High Pressure Ethylene-Nitrous Oxide Mixtures

Prashanth Bangalore Venkatesh (8122676) 20 December 2019 (has links)
<div>Nitrous oxide (N<sub>2</sub>O) has gained popularity as a unique oxidizer due to its ability to decompose exothermically, producing nitrogen and oxygen. Additionally, there are concerns about the safety of nitrous oxide in the nuclear industry where it has been observed that stored nuclear waste generates and retains large amounts of flammable</div><div>gases such as hydrogen and ammonia along with nitrous oxide. These gases are at risk of explosion even in the presence of a weak ignition source which can result in detonations more violent than those initiated directly. Nitrous oxide is also finding an application in the geothermal industry where it is being tested in combination with ethylene as a stimulant mixture to fracture rock. The detonations initiated in this mixture have the ability to produced a network of fractures in the rock formation. In the rocket industry, nitrous oxide has been used for propulsion in multiple systems, but never in a detonative mode. In order to use nitrous oxide in these areas, its detonation properties in combination with a fuel require quantification. Available literature on nitrous oxide-hydrocarbon detonations is mainly restricted to initial pressures below one atm or with dilution. Therefore, detonations with nitrous oxide as the oxidizer are far from being completely characterized. In addition to this lack of general knowledge, understanding of nitrous oxide-fuel detonations at higher pressures, more typical of practical combustion systems is either extremely limited or</div><div>non-existent.</div><div><br></div><div>In the current work, the flame acceleration, deflagration-to-detonation transition (DDT), and detonation properties of a bipropellant mixture of ethylene (C<sub>2</sub>H<sub>4</sub>) and N<sub>2</sub>O are studied as a function of initial pressures. These properties are compared to those in mixtures of ethylene-oxygen (O<sub>2</sub>). these detonations are investigated in a combustion tube designed and fabricated in-house. The performances of these two mixtures are also investigated using theoretical Chapman-Jouguet detonation calculations as a basis of comparison with the measured properties. Additionally, detonation properties in a mixture of acetylene (C<sub>2</sub>H<sub>2</sub>) and nitrous oxide are also investigated to compare the two fuels. While C<sub>2</sub>H<sub>2</sub> is a highly energetic fuel with theoretically high performance, it presents serious practical storage concerns when considered for propulsion applications. These practical issues motivates the investigation of C<sub>2</sub>H<sub>4 </sub>as a potential alternative fuel, which is relatively easy to manage. </div><div><br></div><div>A critical requirement for the application of bipropellant mixtures to detonation systems is rapid flame acceleration to achieve significant chamber pressure rise in a short distance with the potential for a prompt transition to detonation. This DDT behavior of mixtures using N<sub>2</sub>O and O<sub>2</sub> with C<sub>2</sub>H<sub>4</sub> and C<sub>2</sub>H<sub>2</sub> is investigated for increasing initial pressures in the experimental portion of this work. This behavior is quantified by measuring the run-up distances leading to DDT. The pre-compression of the bipropellant mixtures during flame acceleration caused by the accelerating flame is also estimated and directly measured using appropriate instrumentation. These direct measurements of pre-compression are further used to estimate the path of the</div><div>accelerating flame in the combustion tube. These estimates are compared with the flame tracked by high-speed imaging in an optically accessible combustion tube.</div>
120

Nitrous oxide emissions from deammonification process under different operation conditions.

Mazurek, Agnieszka January 2015 (has links)
Wastewater treatment plays significant role in the environmental protection. The process has direct impact on quality of air and water. All treated sewage reaches fresh water reservoirs as well as gasses escaping from the process are emitted to the atmosphere. Main aim of the thesis is to determine N2O emissions from partial nitritation/Anammox (deammonification process) in one-stage system applied in MBBR technology. Whole project was operated successfully on two pilot-scale reactors parallel, fed by the same reject water. Both reactors were filled to capacity of 200 L each, where 40% of the working volume was fulfilled by Kaldnes carriers suspended in liquid by mechanical stirrer. First reactor (R1) presented strategy of intermittent aeration with ratio (R=1/3) and stable DO concentration at amount of 1.5 mg O2/L, whereas second one (R2) operated in constant aeration with variable values of dissolved oxygen which differ in range of 1.0-2.5 mg O2/L. Every week analyses of ammonium and nitrogen forms were carried out in influent and effluent by Hach-Lange cuvettes. Results of measurements showed high NH4+-N removal efficiency of approximately 95% for R1 reactor and 86% for R2. During the process, the continuous measurement of nitrous oxide in gaseous and liquid phase was performed by Teledyne data logger and Unisense microsensor. Measurements during 4 months resulted in assessment of nitrous oxide emission tendency dependent on aeration system. The result from reactor R1 showed that 1.0-2.4% of N-load was emitted as N2O to the atmosphere, and 0.05-0.28% was released as dissolved N2O in outgoing water. Regarding reactor R2 tendency of nitrous oxide production is similar. Estimated emission of N2O in gaseous phase in reactor R2 is 1.4-2.0% of nitrogen load and 0.02-0.39% in liquid phase. All gathered results are shown in the appendix of the paper.

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