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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

O Estudo do comportamento dos gases-traco Osub(3), NOx, CO, SOsub(2) e de COVs na atmosfera da cidade de Sao Paulo

PRETTO, ANGELICA 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:49:38Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:02:17Z (GMT). No. of bitstreams: 1 10427.pdf: 11180152 bytes, checksum: f8294650781a8994bcbc91409d2cadb8 (MD5) / Tese (Doutoramento) / IPEN/T / Intituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP
112

Estudo das concentrações de óxidos de nitrogênio em área urbana do município de Manaus por analisadores automáticos

Coelho, Ilsa Maria Honório de Valois 05 October 2012 (has links)
Submitted by Lúcia Brandão (lucia.elaine@live.com) on 2015-07-15T17:30:28Z No. of bitstreams: 1 Tese - Ilsa Maria Honório de Valois Coelho.pdf: 2443935 bytes, checksum: c16d835d602a5d9906c0038a9cd0dd64 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-07-20T17:53:25Z (GMT) No. of bitstreams: 1 Tese - Ilsa Maria Honório de Valois Coelho.pdf: 2443935 bytes, checksum: c16d835d602a5d9906c0038a9cd0dd64 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-07-20T17:57:14Z (GMT) No. of bitstreams: 1 Tese - Ilsa Maria Honório de Valois Coelho.pdf: 2443935 bytes, checksum: c16d835d602a5d9906c0038a9cd0dd64 (MD5) / Made available in DSpace on 2015-07-20T17:57:14Z (GMT). No. of bitstreams: 1 Tese - Ilsa Maria Honório de Valois Coelho.pdf: 2443935 bytes, checksum: c16d835d602a5d9906c0038a9cd0dd64 (MD5) Previous issue date: 2012-10-05 / CNPq - Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico / This work makes a NOx concentrations study in the urban atmosphere of Manaus city, focusing on the specific meteorological influences of the equatorial region. Initially, we make a historical contextualization about atmospheric pollution and fuel oil consumption, making the relation between pollution, city and urban population development. The importance that chemical knowledge has been in this process is pointed out, enphasizing the Chemical Science as the basis for all the human development. The difficulties of energy supply whose origins come from the beginnings of Amazon development, the vehicle fleet increasing and Manaus city atypical growth, are also discussed according to relations that they have with the problems of quality air. Starting from the prior knowledge of the atmospheric composition and fisicochemical fenomena which happen naturally, we seek to understand the effects from the NOx concentration increase, as well as the possible secondary pollutants, produced by photochemical reactions. The NOx emissions data were collected during the period from February to July in 2011, besides the meteorological conditions like temperature, relative humidity, wind speed, pluviosity and solar radiation. The collection was done, near to Industrial District, and Brazil’s largest thermoelectric complex, in the district of Mauazinho. The automated analysers were used, which store the results through a computerized system, and the meteorological data were supplied by Meteorogical National Institut (INMET). The results showed an increasing deterioration of air quality in the region, with 32 overtaking the limits recommended by the World Health Organization, and June was the most polluted month in the months surveyed. It concludes that the high number of TPP's and the climatic conditions in the Amazon Region are decisive for NOx concentration levels. This implies the need to formulate an environmental air quality diagnostic in the city of Manaus and thus, to support the government in establishing the requirements for issuance of appropriate levels, by stationary and mobile pollution sources. / Este trabalho realiza um estudo das concentrações de NOx na atmosfera urbana do município de Manaus, com foco nas influências meteorológicas específicas da região equatorial. Faz-se inicialmente, uma contextualização histórica da poluição atmosférica e do uso de combustíveis fósseis, relacionando a poluição decorrente com o desenvolvimento da cidade e da população urbana. A importância que os conhecimentos químicos tiveram nesse processo é ressaltada destacando-se a Ciência Química como a base para todo o desenvolvimento da humanidade. As dificuldades de fornecimento de energia, cujas origens remontam aos primórdios do desenvolvimento do Amazonas, o aumento da frota veicular e o crescimento atípico da cidade de Manaus também são discutidos em função da relação que guardam com os problemas de qualidade do ar. Partindo do conhecimento prévio da composição atmosférica e dos fenômenos físicos e químicos que ocorrem naturalmente, busca-se entender os efeitos do aumento da concentração de NOx, bem como de possíveis poluentes secundários produzidos por reações fotoquímicas. Foram coletados dados das emissões de NOx, durante o período de fevereiro a julho de 2011, além das condições meteorológicas como temperatura, umidade relativa, velocidade do vento, pluviosidade e insolação. A coleta foi feita nas proximidades do Distrito Industrial e do maior complexo termelétrico do Brasil, no bairro do Mauazinho. Foram utilizados analisadores automáticos que armazenam os resultados através de um sistema computadorizado e os dados meteorológicos foram fornecidos pelo Instituto Nacional de Meteorologia (INMET). Os resultados mostraram um crescente agravamento da qualidade do ar na região, com 32 ultrapassagens aos limites recomendados pela Organização Mundial de Saúde, sendo o mês de junho, o mais poluído entre os meses pesquisados. Conclui-se que o elevado número de UTE’s e as condições climáticas predominantes na região em estudo tenham sido determinantes para os níveis de concentração dos NOx implicando na necessidade de formulação do diagnóstico da qualidade do ar ambiental na cidade de Manaus para, dessa forma, subsidiar o poder público no estabelecimento das exigências de níveis adequados de emissão das fontes de poluição fixas e móveis.
113

Theoretical and Experimental Linewidth Parameters in the Rotational Spectrum of Nitrogen Dioxide

Moazzen-Ahmadi, Mohamad Nasser 12 1900 (has links)
Contributions to the second order collision efficiency function S ⁽²⁾ (b), used in semiclassical perturbation approaches to pressure broadening of microwave and infrared spectra, due to several leading terms, dipole and quadrupole components, in the expansion of the intermolecular interaction energy are derived by method of irreducible spherical tensor operators for molecules of arbitrary symmetry. Results are given explicitly in terms of dipole and quadrupole line strengths. General expressions for dipole moment line strength in the asymmetric rotor basis as well as quadrupole moment line strength for the special case of molecules with two independent quadrupole moment components are derived. Computer programs for calculating linewidth parameters in the rotational spectrum of ¹⁴NO₂ based on Anderson and Murphy and Boggs theories are presented.
114

Efektivní a ekologické spalování biomasy / The Effective and Ecological Burning of Biomass

Špiláček, Michal January 2018 (has links)
This work deals with the creation of a numerical model of a biomass combusting chamber on a grate. The research part of this work describes the basic properties of biomass important for its combustion and the biomass combustion process itself. For this process which it is necessary to know the dynamics of the chemical reactions and the overall mechanism of a grate combustion of fuels. It also describes the production of harmful emissions that can be generated by combustion of biomass and the emphasis is mainly on the production of nitrogen oxides. In the next part is described the combustion device itself and the basic mathematical model which incorporates the mechanisms of heat transfer, flow of fluids and transport of chemical species. The basic mathematical model is then extended to a complete mathematical model by determining the initial and boundary conditions. Subsequently, the results of the computer simulation of the mathematical model are presented and commented. The main focus are the emissions of nitrogen oxides and hydrocarbons. These results are used to design an improvement of the geometry of the combustion chamber.
115

Zneškodňování spalin znečištěných NOx / Treatment of flue gas polluted by NOx

Hanák, Libor January 2009 (has links)
There is an overview of secondary methods for NOX removal from stationary sources in the first part of master’s thesis. There are well known methods as SCR o SNCR, but also new and experimental ones. An accent is putting on catalytic filtration, especially on cloth filter, which will be used for experiments. An important part of master’s thesis is a project of new experimental unit for experiments with cloth and ceramic catalytic filters as well as with a bit of cloth filtration material. Unit has compact proportions, high-class measurement and control and wide application spectra. Other advantages of this equipment are fast and easy cleaning and installation. This unit, called INTEQ II, can be used in plants or in laboratories. There is prediction model created together with new technology. It enables calculation of efficiency at catalytic filters with variable conditions without many experiments. This model is elaborate and will be finished with dates from measuring. There in only summary of planned experiments in this thesis, because measurements at new unit have not done yet. Experiences with operations at unit INTEQ I were used for proposal of new equipment and for experiments planning.
116

Redukce NOx obsažených ve spalinách / Reduction of NOx contained in flue gas

Janík, Prokop January 2012 (has links)
Research in the field of NOX abatement has grown significantly in the past two decades. The general trend has been to develop new catalysts with complex materials in order to meet the stringent environmental regulations. The master’s thesis deals with the cleaning flue gases through a filter element which is from porous ceramics. There is catalyst implemented for NOx reduction throug the method of selective catalytic reduction in the filter element. There is also description of experimental unit for flue gas cleaning. Part of the thesis is creation of prediction model which allows to predict efficiency reduction in the filtration device operating conditions with some accuracy.
117

La qualité de l’air en milieu aéroportuaire : étude sur l’aéroport Paris-Charles-De-Gaulle

Puente-Lelièvre, Céline 13 May 2009 (has links)
Ce travail de thèse a porte sur l’évaluation de la qualité de l’air sur l’aéroport Paris-Charles- De-Gaulle. L’objectif était d’évaluer l’impact de l’activité aéroportuaire à l’échelle locale et régionale. Cette étude s’est centrée sur les observations à long terme des concentrations des oxydes d’azote (NOx), d’ozone (O3) et des hydrocarbures. Nous avons quantifié la contribution de l’activité aéroportuaire sur les concentrations des NOx observées sur les stations CDG-nord et CDG-sud. Les résultats ont montré que cette contribution était de 18% (12 μ g.m−3) sous un vent du sud et de 47% (25 μ g.m−3) sous un vent du nord. Cette analyse a été réalisée à partir de 3 ans de mesures (2005-2007). Les concentrations des NOx ont également été analysées à l’aide d’un modèle neuronal. Ce modèle a été construit pour estimer les concentrations des NOx en fonction de paramètres météorologiques (direction du vent, vitesse du vent, température, hauteur de la couche limite) et temporels (jour de l’année, heure du jour et la différence entre les jours de la semaine et du week-end). Le modèle a permis d’estimer les concentrations des NOx pour des scénarios ponctuels. Des campagnes de mesures ciblées sur les hydrocarbures ont été mises en oeuvre au cours de cette thèse. Elles ont permis de caractériser la spéciation des hydrocarbures émis par les moteurs d’avion. Les résultats ont montré que cette spéciation était similaire de celle observée pour les véhicules diesel. Ceci ne permet pas d’établir clairement un profil caractéristique permettant de distinguer les émissions des avions de celles de véhicules. La spéciation des hydrocarbures sur la plate-forme a également été évaluée. Les résultats ont montré que la spéciation des hydrocarbures observée sur la plate-forme est comparable à celle observée en milieu urbain et dans d’autres milieux aéroportuaires. Par ailleurs, les concentrations moyennes observées étaient typiquement de l’ordre de celles observées dans une atmosphère urbaine. L’estimation de l’impact des activités aéroportuaires à l’échelle régionale a fait l’objet d’une étude préliminaire à l’aide d’un modèle de chimie-transport, CHIMERE. Cette étude a permis d’évaluer l’étendue spatiale de l’impact de l’activité aéroportuaire pour deux épisodes. Ces épisodes correspondent à un épisode de pollution estival à l’ozone et hivernal au NO2. Les simulations ont indiqué une contribution inférieure à 5μ g.m−3 à une quinzaine de kilomètres sous le vent de l’aéroport / The work presented here deals with the evaluation of air quality at Paris-Charles-de-Gaulle airport. The objective was to evaluate the local and regional impact of airport activity. This study is centered on long term measurements of nitrogen oxides (NOx), ozone (O3) and hydrocarbons concentrations. We calculated the contribution of airport activity to NOx concentrations in north and south stations. Results showed this contribution was 18% (12 μ g.m−3) from southern wind and 47 % (25 μ g.m−3) from northern wind. This analysis had been performed from 3 years data (2005-2007). NOx concentrations had been also analyzed with a neuronal model. This model was built in order to estimate concentrations according to meteorological (wind direction, wind velocity, temperature, boundary layers) and temporal parameters (day, hour, difference between week-day and week-end). The neuronal model allowed to estimate NOx concentrations for punctual scenarios. Field campaigns targeting hydrocarbons were conducted during this thesis. The speciation of hydrocarbons emitted by engine aircraft was characterized. These results showed engine aircraft hydrocarbon speciation was similar to motor diesel hydrocarbon speciation. This does not allow for the clear establishment of a characteristic profile that differentiates aircraft emissions from those of vehicles. Hydrocarbon speciation observed at the airport was also evaluated. Results showed that the hydrocarbon speciation detected at the airport was comparable to that observed within an urban environment as well as at other airports. Moreover, average concentrations were akin to those observed within an urban environment. The estimation of regional impact of airport activity was preliminary studied with a chemicaltransport model, CHIMERE. This study permitted the evaluation of the spatial extent of the impact of airport activity for two episodes. These episodes correspond to summer pollution by ozone and winter pollution by NO2. Simulations showed the contribution downwind of the airport was lower than 5 μ g.m−3 for 15 km
118

AN EVALUATION OF NITROGEN OXIDE EMISSION FROM A LIGHT-DUTY HYBRID-ELECTRIC VEHICLE TO MEET U.S.E.P.A. REQUIREMENTS USING A DIESEL ENGINE

Paciotti, Robert Neil 13 September 2007 (has links)
No description available.
119

Theoretical Study on the Mechanism of Removing Nitrogen Oxides using Isocyanic Acid.

Nowroozi-Isfahani, Taraneh 01 August 2001 (has links) (PDF)
The mechanism of RAPRENOx reactions - RAPid REduction of Nitrogen Oxides using Isocyanic acid - proposed by Robert A. Perry1 in an attempt to help control the emission of nitrogen oxides pollutant into the atmosphere, has been re-investigated theoretically. The study of reaction mechanisms was carried out using Chemist software2. All mathematically possible elementary steps have been evaluated and the chemically reasonable ones have been considered to propose new sets of reaction mechanisms. Density Functional Theory (B3LYP/6-31 G**) calculations using Gaussian 983 were made in order to study the relative energies of all species and to predict the energy barrier of each elementary step. As a consequence of our study, there are two more sets of reaction mechanisms (in addition to Perry’s mechanism), that could be possible for the propagation step of RAPRENOx process.
120

Performance and emissions study of diesel and waste biodiesel blends with nanosized CZA2 of high oxygen storage capacity

Pimenidou, Panagiota, Shanmugapriya, N., Shah, N. 29 November 2018 (has links)
Yes / In this work, the effect of the nanosized CZA2 (cerium-zirconium-aluminium) on the performance and emissions in a two- cylinder indirect injection (IDI) diesel engine, was studied. CZA2 was dispersed in diesel (D100) and waste cooking oil and tallow origin biodiesel-diesel blends (B10, B20, B30) and tested at different engine loads and constant speed. The nanocatalyst (CZA2) increased the brake specific fuel consumption (BSFC) and decreased the brake thermal efficiency (BTE, %) of all tested fuels, at all loads, except B20 at the lowest load. CZA2 reduced nitrogen oxides (NOx) from D100 at low and high engine loads, as well as carbon monoxide (CO) and unburned hydrocarbons (HC) at medium and high tested loads. The dispersion of CZA2 promoted the combustion of the biodiesel blends by almost eliminating HC while reducing NOx and CO emissions at various loads. Thermogravimetric analysis (TGA) coupled with Attenuated Total Reflectance- Fourier Transform Infrared (ATR-FTIR) spectroscopy revealed that the addition of CZA2 in diesel and biodiesel under pyrolysis and oxidation conditions resulted in the presence of saturated species like ketones and final oxidation products such as CO2, supporting their improved combustion and emissions’ reduction in the engine tests.

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