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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.
91

Mobile Laboratory Measurement of Black Carbon, Particulate Polycyclic Aromatic Hydrocarbons and Other Exhaust Emissions in Mexico City

Jiang, Mei 28 March 2005 (has links)
Black carbon (BC) and polycyclic aromatic hydrocarbons (PAHs) are two atmospheric pollutants produced by motor vehicles using carbonaceous fuels. As a part of the Mexico City Project, measurements of BC, PPAHs and many other gas- and particle-phase emissions were measured in Mexico City using a mobile laboratory during the Mexico City Metropolitan Area field campaign in April 2003 (MCMA-2003). The main goal of this research is to estimate emissions of BC and particulate PAHs (PPAHs) for Mexico City's vehicle fleet. The emissions of gas-phase pollutants such as carbon monoxide (CO), total nitrogen oxides (NOy) and volatile organic compounds (VOC) are also estimated. The mobile lab has previously been used to chase vehicles and measure their emissions, but analysis has traditionally focused on determining emission factors of individual vehicles associated with specific chasing events. The laboratory continuously samples ambient air from an inlet at the front of the van, and it is always "seeing" exhaust plumes from the vehicles around it while driving through traffic. We have developed an algorithm that automatically identifies the exhaust plume measurement points, which are then used as the basis for calculation of emission factors. In the nearly 90 hours of on-road sampling during the field campaign, we have identified ~30,000 exhaust measurement points. The large sample size enables us to estimate fleet-average emission factors and thus the emission inventory. Motor vehicles are estimated to emit annually 1,960 tons of BC, 56.2 tons of PPAHs, 1,320,000 tons of CO, 125,000 tons of NOy and 2440 tons of VOCs. The spatial and temporal patterns of BC and PPAHs in different locations with in MCMA are also studied. / Master of Science
92

Effets de la pollution atmosphérique particulaire sur la circulation pulmonaire : rôles du stress oxydant et de la signalisation calcique. / Effects of airborne particulate matter on the pulmonary circulation : roles of oxidative stress and calcium signaling

Deweirdt, Juliette 07 December 2018 (has links)
L’exposition humaine aux particules atmosphérique (PM) est une préoccupation majeure de santé publique. La pollution particulaire est constituée de particules grossières (PM10 diamètre < 10 μm), de particules fines (PM2.5 diamètre < 2.5 μm) et de particules ultrafines (PUF ou PM0.1 diamètre < 100 nm). L’excès de mortalité constaté par les études épidémiologiques est principalement associé aux pathologies respiratoires et cardiovasculaires. Après inhalation, les particules les plus fines (PM2.5 et PUF) pénètrent profondément dans les voies respiratoires jusqu’aux alvéoles pulmonaires. Des études ont montré qu’elles peuvent franchir la barrière alvéolo-capillaire pour se retrouver dans la circulation systémique et y exercer leurs effets délétères sur les organes cibles tel que le système cardiovasculaire. La circulation pulmonaire constitue donc une cible privilégiée des particules inhalées, particulièrement les cellules endothéliales qui tapissent la lumière des vaisseaux. L’hypertension pulmonaire (HTP) est une pathologie de la circulation pulmonaire caractérisée par un remodelage des vaisseaux pulmonaires, une hyperréactivité et une inflammation. Des études récentes ont montré le rôle prépondérant du calcium et du stress oxydant dans la physiopathologie de cette maladie. Cependant, peu d’études mécanistiques visent à expliquer les effets des PM sur les cellules cibles vasculaires pulmonaires. Dans ce contexte, ce travail vise à mieux caractériser les effets cellulaires et moléculaires des particules sur les cellules endothéliales d’artères pulmonaires humaines (HPAEC). L’impact des PM2.5 et des nanoparticules (NPs) noires de carbone (FW2) sur les cellules endothéliales d’artères pulmonaires humaines entraine des dérégulations de l’homéostasie cellulaire. En effet, nos résultats montrent une augmentation significative du stress oxydant et, notamment, de la production d’anion superoxyde cytoplasmique et mitochondrial, des perturbations de la signalisation calcique, des dommages mitochondriaux, ainsi qu’un déséquilibre de la sécrétion de facteurs vasoactifs tels que le monoxyde d’azote (NO). Nous avons, également, étudié sur ces cellules cibles vasculaires pulmonaires humaines, dans des conditions physiologique et pathologique mimant l’HTP, les effets des particules sur la signalisation calcique ainsi que le rôle du stress oxydant dans les effets observés. Nous avons, dans un premier temps, développé et validé un modèle in vitro qui mime la dynamique vasculaire observée dans l’HTP. Dans une deuxième étape, nous avons observé les effets des NPs FW2, dans les deux conditions expérimentales. Nos résultats montrent, dans les cellules placées en conditions pathologiques, une augmentation significative de la production d’espèces réactives de l’oxygène (ERO) ainsi qu’une augmentation significative de la réponse pro-inflammatoire caractérisée par la sécrétion d’interleukines telles que l’IL-6 par rapport aux cellules placées en condition physiologique. De plus, la signalisation calcique semble également altérée dans les conditions pathologiques. / Human exposure to airborne particulate matter (PM) is a health risk concern. Particulate air pollution is composed of different PM: coarse particles (PM10 diameter < 10 μm), fine particles (PM2.5 diameter < 2.5 μm) and ultrafine particles (UFP) (PM0.1 diameter < 100 nm). The excess of mortality observed in several epidemiological studies is mainly associated with respiratory and cardiovascular diseases. After inhalation, the finest particles (PM2.5 and UFP) penetrate deeply into the airways, accumulate in pulmonary alveoli, cross the epithelial barrier to reach the pulmonary circulation and exert deleterious effects on the cardiovascular system. Inhaled particles are therefore observed in the pulmonary circulation, in direct contact with endothelial cells lining the inner surface of blood artery. Pulmonary Hypertension (PH) is the main disease of the pulmonary circulation characterized by remodeling of the pulmonary wall, changes in pulmonary vascular hyperactivity and inflammation. Oxidative stress and alteration in calcium signaling are also critical events involved in the physiopathology of PH. However, the effect of PM on these pulmonary vascular cellular targets is poorly described. In this context, the objectives of the present study are to assess the cellular and molecular effects of particle exposures in human pulmonary artery endothelial cells (HPAEC). Our results highlighted various cellular homeostasis alterations of HPAEC in response to PM2.5 and black carbon nanoparticles (FW2 NPs). We observed a significant increase of oxidative stress including cytoplasmic and mitochondrial superoxide anion production in concentration dependent-manner. Moreover, we observed calcium signaling alterations, mitochondrial damages, as well as a deregulation of vasoactive factors secretion such as nitric oxide (NO). Finally, we studied these cellular targets under physiological and pathological conditions mimicking PH. We have first developed a new in vitro model that mimics the vascular dynamics observed in the PH. Then, we investigated the effects of FW2 NPs in both experimental conditions. Our results showed, in pathological conditions, a significant increase in reactive oxygen species (ROS) production and a significant increase in the pro-inflammatory response characterized by interleukin secretion such as IL-6 as compared to cells in physiological condition. In addition, the calcium signaling seemed also be impaired in pathological conditions.
93

Development of photonic instruments for measurement of aerosol optical properties / Développement des instruments photoniques pour les mesures des propriétés optiques des aérosols

Wang, Gaoxuan 29 January 2018 (has links)
À cause de leur diffusion et de leur absorption des radiations solaires, les aérosols atmosphériques jouent un rôle important dans l'évolution du climat terrestre. Les techniques de mesure actuelles apportent certes, des connaissances, sur le forçage radiatif mais les résultats possèdent généralement de larges incertitudes, souvent du même ordre de grandeur que la valeur elle-même. Ces incertitudes sont causées par le manque de précision sur les données liées aux propriétés optiques estimées de ces aérosols (comme l'absorption, la diffusion ou l'extinction). Elles découlent principalement des techniques de mesures actuelles : à l'effet de chargement des filtres (lors de mesures classiques par filtres), aux mesures limitées par l'étendue spectrale des instruments, aux conditions d'échantillonnage différents lors de mesures séparées, etc. Dans ce travail de thèse, j'ai développé puis testé des instruments optiques et électroniques dans le but d'augmenter la précision des mesures des coefficients d'extinction et d'absorption des aérosols. (1) Deux spectrophones PhotAccoustique (PA) sont développés afin d'améliorer les mesures d'absorption des aérosols grâce à des mesures directes et sans filtres. Une première génération utilisant un rayonnement à 444 nm permet de réduire les incertitudes de mesure de 20-30% (obtenue par la technique d'échantillonnage par filtres) à 7,4% et 4,6% pour la détermination des coefficients d'absorption massique du carbone suie et de cendres volcaniques, respectivement. Transformé en spectrophone PA à multi-longueurs d'onde opérant conjointement à 444,532 et 660 nm, il permet alors de caractériser la dépendance spectrale du Coefficient d'Absorption d'Ångström (CAA). Les valeurs du CAA du carbone suie sont en accord avec les résultats publiés. Celles obtenues lors de l'analyse de deux échantillons de cendres volcaniques résultant de l'éruption du Eyjafjallajökull sont similaires au CAA du carbone brun,prouvent la présence d'importantes quantités d'éléments organiques. (2) Un extinctiomètre, basé sur le principe de la spectroscopie d'absorption en cavité à source large bande et incohérente (IBBCEAS), est ensuite développé afin de suivre l'évolution des propriétés optiques d'Aérosols Organiques Secondaires (AOS) produits par la photolyse du 2-nitrophénol dans une chambre de simulation atmosphérique de l'University College de Cork (Irlande). Leurs coefficients d'extinction et d'absorption sont suivis par cet extinctiomètre et un spectrophone PA durant tout le processus de production. Les évolutions des propriétés optiques des AOS confirment l'effet du vieillissement atmosphérique. (3) Une nouvelle architecture de détection synchrone est développé afin de rendre notre prototype plus léger, plus compact, mieux adapté aux applications in situ et plus particulièrement aux drones, techniques émergentes qui permettent de caractériser le profil vertical des aérosols dans l'atmosphère. Cette détection synchrone innovante, évaluée lors de la mesure de la concentration de NO₂ ambiant (niveau de concentration de quelques ppbv) possède une précision et une reproductibilité de mesures comparable à la détection synchrone SR830, commercialisée par la société Stanford Research Inc. L'évaluation précise de l'impact climatique des aérosols nécessite une quantification exacte et non biaisée de leurs propriétés optiques. À ce jour, elle reste un défi majeur dans la recherche sur les sciences de l'atmosphère et du changement climatique. Ainsi, des informations sur la taille des particules (liée à l'absorption sélective en longueur d'onde) nécessitent des mesures étendues sur de larges régions spectrales du rayonnement solaire principale. Le développement d'un albédomète large bande à haute précision, dédié à la mesure simultanée des coefficients d'extinction et d'absorption des aérosols est en cours. / Atmospheric aerosols are known to play an important role in earth climate by scattering and absorbing solar radiation. However, the aerosol radiative forcing effect is still known with large uncertainties (almost equal to the magnitude of the aerosol radiative forcing). The uncertainties are mainly caused by inaccurate estimates of aerosol optical properties (such as its absorption, scattering and extinction coefficients) using the currently available measurement techniques, with result in filter loading effect in classic filter technique, the uncertainty due to different sampling conditions for separate measurements of aerosol optical properties in combination of different techniques or due to the measurements at limited spectral wavelength ranges. My PhD work was carried out on the developments and applications of optical and electronic instruments for accurate measurements of aerosol extinction and absorption coefficient : (1) Photoacoustic spectrophones were developed for filter-free direct measurements of aerosol absorption with high accuracy. Measurements uncertainties down to about 7.4% and 4.6% (compared to about 20-30% in filter-based measurements) were achieved for the determination of mass absorption coefficients of black carbon and volcanic ash samples, respectively, using a single-wavelength PA spectrophone operating at 444 nm. A 3-wavelength PA spectrophone operating at 444,532 and 660 nm was developed and deployed for characterizing wavelength-dependent optical properties of aerosol absorption Ångström coefficient (AAC). The determined AAC of black carbon was well consistent with the previously reported value. Our AAC values of two volcanic ash samples from 2010 eruptions of Eyjafjallajökull, similar to the AAC of brown carbon, indicated abundant organic compounds in the volcanic ash samples. The developed multi-wavelength PA spectrophone was tested and validated in an intensive field campaign measurements of environmental particles in Grenoble (France). Side-by-side inter-comparison measurements using an aethalometer showed a lineat correlation of the measured aerosol absorption coefficients from both instruments. (2) An extinctiometer based on IBBCEAS was developed for study of optical properties of secondary organic aerosol (SOA) produced from photolysis of 2-nitrophenol in an atmospheric simulation chamber at University College Cork (Ireland). Simultaneous monitoring of the SOA extinction and absorption (in conjuction with a PA spectrophone) coefficients was performed during its whole production process, the measured evolutions of the SOA optical properties highlighted the atmospheric aging effect. (3) In order to render optical sensor lightweight and suitable for field applications, in particular for the newly emerging unmanned aerial vehicle (UAV) applications, a novel architecture of lock-in amplifier (LIA) was proposed and developed in the framework of this Phd Research. The novel LIA, evaluated with an inter-comparison measurement of ambient NO₂ at the ppbv concentration level, shows an identical performance (in terms of measurements accuracy and precision) as the widely used commercial LIA (SR830, Stanford Research Inc.), while using a simplified and lightweight hardware architecture. Evaluation of the aerosol impact on climate requires accurate and unbiased quantification of the its wavelength-dependent optical properties over a wide spectral region of the major solar radiation, which can provide information on particle size (due to the wavelength dependence of scattering by fine particles) as well as insights on aerosol chemical composition (because of its wavelength selective absorption). To date, it is still a key challenge in atmospheric science and climate change research. Development of a broadband aerosol albedometer is ongoing, which is dedicated to simultaneous measurements of aerosol extinction and absorption coefficients with high-accuracy and high-precision.
94

Assessing urban air quality through measurements and modelling and its implications for human exposure assessment

Wu, Hao January 2017 (has links)
Outdoor air pollution is a major contributor to adverse health effects of citizens, in particular those living in urban environments. Air quality monitoring networks are set up to measure air quality in different environments in compliance with national and European legislation. Generally, only a few fixed monitoring sites are located within a city and thus cannot represent air pollutant concentrations in urban areas accurately enough to allow for a detailed human exposure assessment. Other approaches to derive detailed urban air pollutant concentration estimates exist, such as dispersion models and land-use regression (LUR) models. Low-cost portable air quality monitors are also emerging, which have the potential to add value to existing monitoring networks by providing measurements at greater spatial resolution and also to provide individual-level exposure assessment. The aim of this thesis is to demonstrate how measurements and modelling in combination allow detailed investigations of the variability of air pollutants in space and time in urban area, and in turn improve on the current exposure assessment methods. Three types of low-cost portable monitors measuring NO2, O3 (Aeroqual monitors) and PM2.5 (microPEM monitor) were evaluated against their respective reference instruments. The Aeroqual O3 monitor showed very good correlation (r2 > 0.9) with the respective reference instruments, but biases in the slope and intercept coefficients indicated that calibration of Aeroqual O3 monitor was needed. The Aeroqual NO2 monitor was subject to cross-sensitivity from O3, which, as demonstrated, can be effectively corrected by making O3 and NO2 measurements in tandem. Correlation between the microPEM monitor and its reference instrument was poor (r2 < 0.1) when PM2.5 concentrations were low (< 10 μg m-3), but significantly improved (r2 > 0.69) during periods with elevated PM2.5 concentrations. Relative humidity was not found to affect the raw results of PM2.5 measurements in a consistent manner. All three types of monitors cannot be used as equivalent or indicative methods instead of reference methods in studies that require quantification of absolute pollutant concentrations. However, the generally good correlations with reference instruments reassure their application in studies of relative trends of air pollution. Concentrations of PM2.5, ultrafine particles (UFP) and black carbon (BC) were quantified using portable monitors through a combination of mobile and static measurements in the city of Edinburgh, UK. The spatial variability of UFP and BC was large, of similar magnitude and about 3 times higher than the spatial variability of PM2.5. Elevated concentrations of UFP and BC were observed along streets with high traffic volumes whereas PM2.5 showed less variation between streets and a footpath without road traffic. Both BC and UFP significantly correlated with traffic counts, while no significant correlation between PM2.5 and traffic counts was observed. The relationships between UFP, NO2 and inorganic components of PM2.5 were further investigated through long-term measurements at roadside, urban background and rural sites. UFP moderately correlated with NOx (NO2 + NO) and showed varying relationships with NOx depending on the particle size distribution. Principal component analysis and air-mass back trajectory analysis revealed that PM2.5 concentrations were dominated by long-range transport of secondary inorganic aerosols, whereas UFP were mainly related to varying local emissions and meteorological conditions. These findings imply the need for different policies for managing human exposure to these different particle components: control of much BC and UFP appears to be manageable at local scale by restricting traffic emissions; however, abatement of PM2.5 requires a more strategic approach, in cooperation with other regions and countries on emissions control to curb long-range transport of PM2.5 precursors. A dispersion model (ADMS-Urban) was used to simulate high resolution NO2 and O3 concentrations in Edinburgh. The effects of different emission and meteorological input datasets on the resulting modelled NO2 concentrations were investigated. The modelled NO2 and O3 concentrations using the optimal model setup were validated against reference instrument and diffusion tube measurements. Temporal variability of NO2 was predicted well at locations that were not heavily influenced by local effects, such as road junctions and bus stops. Temporal variability of O3 was predicted better than for NO2. Long-term spatial variability of NO2 was found to correlate well with diffusion tube measurements, while modelled spatial variability of O3 in ADMS-Urban compared poorly with diffusion tube measurements. However, it was found that the O3 diffusion tube measurements may be subject to some unidentified biases affecting their accuracy. Land-use regression (LUR) models are widely used to estimate exposure to air pollution in urban areas. An appropriately sized and designed monitoring network is an important component for the development of a robust LUR model. Concentrations of NO2 were simulated by ADMS-Urban at ‘virtual’ monitoring sites in 54 different network designs of varying numbers and types of site, using a 25 km2 area including much of the Edinburgh city area. Separate LUR models were developed for each network. These LUR models were then used to estimate ambient NO2 concentrations at all residential addresses, which were evaluated against the ADMS-Urban modelled concentration at these addresses. The improvement in predictive capability of the LUR models was insignificant above ~30 monitoring sites, although more sites tended to yield more precise LUR models. Monitoring networks containing sites located within highly populated areas better estimated NO2 concentrations across all residential locations. LUR models constructed from networks containing more roadside sites better characterised the high end of residential NO2 concentrations but had increased errors when considering the whole range of concentrations. No particular composition of monitoring network resulted in good estimation simultaneously across all residential NO2 concentration and of the highest NO2 levels implying a lack of spatial contrast in LUR-modelled pollution surface compared with the dispersion model. Finally, the results from the measurement and modelling studies presented in thesis are synthesised in the context of current exposure assessment studies. Low-cost air-quality monitors currently do not possess and are unlikely in the near future to provide the robustness and accuracy to replace the existing routine monitoring network. Development of the low-cost air-quality should be aiming at upgrading them as the indicative method as defined in the data quality objective in the EU directive. The monitoring sites used to build LUR models should capture well the population distribution in the study area as opposed to capturing the greatest pollution contrast. The traditional methods of evaluating LUR models are also ineffective in characterising the models’ capability at estimating pollutant concentration at residential address. Given that the dispersion models are also subject to the availability and uncertainties in the input data, future air quality model development should endeavour to incorporate both dispersion and land-use regression models, where the uncertainty in the input data can be reduced by using LUR models built on actual measurements, and the limitation in the statistical modelling can be replaced by adopting the deterministic approach used in the dispersion model.
95

Characterizing particulate carbon using dielectric property measurements

Syk, Madeleine, Vollmer, Joakim January 2018 (has links)
Interest in effects of carbonaceous particles in the atmosphere has recently taken an upswing due to knowledge of how these particles affect our environment. Carbonaceous aerosols are characterized by their dark color, giving them the ability to absorb both incoming and outgoing radiation of all wavelengths in the atmosphere. If these particles are deposited on snow or ice they blacken the surface, with an increased rate of melting as a consequence. These particles play a significant role in climate change and it is important to characterize the particles in order to determine their environmental impact and their origin. In this thesis, two non-destructive dielectric measurement approaches for characterizing carbonaceous particles at microwave frequencies were explored: measurements with an impedance analyzer and measurements using a cavity resonator. Measurements were carried out on quartz filters containing concentrations of carbon normally found in snow in northern Scandinavia. To validate the carbon concentration on the filters a field trip to northern Sweden was conducted. Snow samples were collected and analyzed in regards of carbon content, confirming that the amount of carbon on the filters were accurate. The impedance analyzer showed great uncertainty and the results were not precise enough to determine the credibility of the approach. Measurements with the cavity resonator showed some promising results due to its extreme sensitivity but require adjustments to distinguish different particle types from each other. Thus, it is expected that the use of a cavity resonator operating at microwave frequencies will become an applicable method for characterizing carbonaceous particles in the future.
96

Parâmetros físico-hídricos, lixiviação de nutrientes e desenvolvimento do girassol (Helianthus annuus L) em argissolo amarelo tratado com biocarvão

Lima, Idamar da Silva 29 February 2016 (has links)
The use of biochar in soil has been reported in countries like Japan and the United States, where the product already has reached commercial scale. The benefits of biochar go beyond improving the physical, chemical and biological soil properties, they involve regional and global environmental aspects, such as carbon sequestration in the soil and the efficient disposal of solid organic waste. This is because its resistant and recalcitrant organic nature. Investigation on the effects of biochar in weathered tropical soils with low water and nutrient storage capacity, as in most Brazilian soils and in the State of Sergipe, it is necessary and may stimulate new sustainable management practices. Therefore, the present study evaluated the effect of differentes rates of application of coconut husk biochar, produced through slow pyrolysis process, in the growth and development of sunflower plants and, in some soil physical and chemical properties. Soil organic carbon storage and soil solution composition were also evalauted. The experiment was conducted under greenhouse conditions at the Federal University of Sergipe, campus of St. Christopher-SE, between the months of July and October 2015. The soil used in the study was the surface layer of an Yellow Ultisol. The experimental design was a randomized complete block with 6 treatments (biochar rates of application: 0, 2.5, 5, 10, 20 and 30t ha-1) and 5 replications. Sixty-two days after plant emergence (DAE), all plants were evaluated for plant height, stem diameter at 2 cm of the soil, number of fully expanded leaves, flower diameter, and plant biomass dry weight. Soil solution was collected after specific irrigation events at 6, 13 and 20 days after plant emergency, and analyzed for pH EC, concentrations of P, K, nitrate and ammonium.Seven and 78 days after the incorporation of biochar, soil samples were collected from each experimental pot and analyzed for chemical (pH, EC, P, and exchangeable K, Na, Al, Ca, Mg concentrations, and organic C) and physical (field capacity, permanent wilting point, total water availability, soil bulk density, macro and microporosity) attributes. The physical attributes were only evaluated after 78 days. The soil carbon storage at the end of the experiment was calculated according to the bulk density and depth of the soil sampling. Adding biochar resulted in an increase in the levels of P and K at a depth of 0-20 cm. The high concentration of K at the 20-40 cm layer indicated that the element was leached from the top layer. Soil EC in the soil solution increased at both soil layers indicating a restriction on the use of large amount of biochar. The presence of biochar in the soil, regardless of the rate of application, did not influence the growth and development of sunflower, which can be seen as a positive effect because it means that this type of biochar can be applied to the soil to store carbon without causing harm to the plants. Biochar reduced the soil bulk density and increased microporosity, and as a result, improved water retention in the soil in about 64% at the highest rate of application. Furthermore, the presence of biochar reduced soil acidity and the availability of Al, but increased the electrical conductivity and the concentration of exchangeable Na, both at the beginning and at the end of the experiment. There was no influence of biochar on exchangeable concentrations of Ca and Mg, but the concentrations of P and K responded positively to the rate of application in the begining of the experiment, when no chemical fertilizers had been added to the soil. A positive response was observed for the K concentration in the end of the experiment. Although the addition of biochar improved the physical and chemistry quality of the soil, its implementation should be well attended due to excessive changes in soil pH and EC, and increase in Na concentration. / A utilização de biocarvão no solo vem sendo divulgada em países como Japão e Estados Unidos, onde o comércio do produto já atinge escala comercial. Os benefícios do uso do biocarvão vão além da melhoria na qualidade física, química e biológica do solo, por se tratar de matéria orgânica de natureza resistente e recalcitrante, alcançam também aspectos ambientais de relevada importância regional e mundial, como o sequestro de carbono no solo e a destinação eficiente dos resíduos orgânicos sólidos. O estudo dos efeitos do biocarvão em solos tropicais intemperizados, com baixa capacidade de armazenamento de água e nutrientes, como a maioria dos solos encontrados no Brasil e no Estado de Sergipe, torna-se necessário e poderá viabilizar novas práticas sustentáveis de manejo. Portanto, o presente trabalho avaliou o efeito da aplicação de biocarvão, produzido a partir de casca de coco seco em processo de pirólise lenta, nos atributos físicos e químicos do solo, no armazenamento de carbono, no desenvolvimento e produção de biomassa do girassol e na composição química da solução do solo em diferentes profundidades de coleta. O experimento foi desenvolvido em condições protegidas na Universidade Federal de Sergipe, campus de São Cristovão-SE, entre os meses de julho e outubro de 2015. O solo utilizado no estudo foi a camada superficial de um Argissolo Vermelho Amarelo. O delineamento experimental foi de blocos casualizados, com 6 tratamentos (doses de biocarvão aplicadas: 0; 2,5; 5; 10, 20 e 30t ha-1) e 5 repetições. Aos 62 dias após a emergência (DAE), todas as plantas foram avaliadas, sendo mensurados altura das plantas, com auxilio de régua graduada, diâmetro do caule a 2 cm do solo, com auxilio de paquímetro digital, número de folhas totalmente abertas, diâmetro do capitulo com auxilio de paquímetro digital e colheita da plantas para determinação da produção de biomassa, já a solução do solo foi coletada após específicos eventos de irrigação, sendo essa coletas realizadas aos 6, 13 e 20 dias após semeadura, sendo analisado nesses extratos o pH, CE, concentrações de fósforo, potássio, nitrato e amônio. Aos 7 e 78 dias após a incorporação do biocarvão, foram avaliados no solo os atributos químicos: pH, CE, P disponível e concentrações de trocáveis de K, Na, Al, Ca, Mg e porcentagem C, sendo na profundidade de 0-20 cm para as amostras coletadas 7 dias após incubação e 0-20 cm e 20-40 cm para as amostras coletadas aos 78 dias e atributos físicos: capacidade de campo, ponto de murcha permanente, disponibilidade total de água, densidade do solo, macro e microporosidade do solo, sendo que as analises físicas foram realizadas apenas aos 78 dias após incubação. O armazenamento de carbono no solo no final do experimento foi calculado de acordo com a densidade do solo e profundidade de coleta do solo. A adição do biocarvão proporcionou um aumento nos níveis de P e K na profundidade de 0-20 cm, porém contribuiu com o aumento na lixiviação de potássio visto que aumentou os níveis desse elemento na profundidade de 20- 40 cm. Aumentou a CE da solução do solo nas duas profundidades estudadas, podendo ser este um limitante a sua utilização em grandes quantidades. Nas doses utilizadas nesses estudos o biocarvão não proporcionou nenhum beneficio nem prejuízos ao desenvolvimento e produção de biomassa do girassol, fato esse que é visto positivamente, pois permite a utilização deste material no solo para outros fins sem causar danos a cultura implantada. A adição do biocarvão reduziu a densidade do solo e aumentou a microporosidade, e como consequência, melhorou a retenção de água no solo em aproximadamente 64% na maior dose aplicada. A presença do biocarvão reduziu a acidez do solo e a disponibilidade de Al, e aumentou a condutividade elétrica e a concentração de Na trocável, tanto no inicio quanto no final do experimento. Não houve influência do biocarvão nas concentrações trocáveis de Ca e Mg, mas as concentrações de P e de K responderam positivamente ao aumento das doses de biocarvão no inicio do ensaio, quando nenhum fertilizante químico tinha sido adicionado ao solo. Também observou-se resposta positiva quanto as concentrações de K no final do experimento. Embora tenha sido observado beneficio do biocarvão na qualidade física e química do solo, e na composição da solução do solo, sua aplicação deve ser bem assistida em função de mudanças excessivas na reação, na sodicidade e na salinidade do solo.
97

Health Effects of Occupational Exposure of Wildland Firefighters to Smoke from Biomass Burning

Wu, Chieh-Ming January 2020 (has links)
No description available.
98

Atmospheric chemical processes : reaction of ozone with 2- and 3-carene, evolution of internal mixed combustion particles / Processus chimiques atmosphériques : réaction de l’ozone avec 2- et 3- carène, réaction de surface et hydratation de particules issues de la combustion

Chen, Hui 09 December 2014 (has links)
Dans cette thèse, nous présentons des travaux complémentaires conduits à ICARE-CNRS (Orléans), partie A et à l’Université de Fudan (Shanghai), partie B. Partie A : les 2-et 3-carène sont deux composés organiques volatils biogéniques importants présents dans l’atmosphère dont les voies de dégradation sont encore mal connues. Afin de déterminer les constantes de vitesse des réactions de ces espèces avec l’ozone, nous avons utilisé trois systèmes expérimentaux complémentaires : des chambres de simulation d’ICARE de 7300L et 80000L (HELIOS) et un réacteur à flux laminaire. Les rendements de certains produits de réactions, le radical hydroxyle (OH), le formaldéhyde (HCHO) et le monoxyde de carbone (CO) ont aussi été déterminés. D’autre part, pour avoir une meilleure compréhension d’intermédiaires de réaction formés lors de l’ozonolyse, appelés intermédiaires de Criegee, un réacteur à flux laminaire à deux étages a été mis en place pour mesurer leurs constantes de vitesse de réaction avec SO2, NO2 et O3. Partie B : les impacts du “black carbon (BC)” et du “brown carbon (BrC)” constituent une incertitude majeure dans les modèles climatiques actuels. Des rapports récents indiquent que la morphologie et l’évolution des BC et BrC dans l’atmosphère jouent un rôle important sur la capacité d’absorption de ces particules. Afin d’étudier leurs comportements, des mélanges de particules (BC-BrC) ont été exposés en chambre de simulation atmosphérique à l'acide sulfurique, au mélange ammoniac / triéthylamine, et à la vapeur d'eau de manière séquentielle. / In this thesis, we present a complementary work conducted at ICARE-CNRS (Orléans), Part A and at Fudan University (Shanghai), Part B. Part A: 2-and 3-carene are two important biogenic volatile organic compounds present in the atmosphere. The knowledge on their degradation pathways and the corresponding products are still poor. Using complementary reaction systems-ICARE 7300 L and HELIOS 80000 L simulation chambers, vertical laminar flow reactor, their kinetic rate constants for reaction with ozone were determined. Additionally, important product formation yields, hydroxyl radical (OH), formaldehyde (HCHO) and carbon monoxide (CO) have been determined with indication to their corresponding formation routes from the ozonolysis of carene. To have a better understanding on reactions of Criegee intermediates (CIs) generated through ozonolysis in the atmosphere, a horizontal 2-stage laminar flow reactor was set up to measure the rate constants of CIs with SO2, NO2 and O3. Part B: Radiative forcing of black carbon (BC) in the atmosphere, as well as that of brown carbon (BrC), remains to be a major uncertainty in current climate models. Recent reports indicate that the absorption enhancement of BC and BrC particles is determined by evolution of morphology and mixing state during the atmospheric processing. Laboratory-generated BC-BrC mixture particles (BC-BrC) were exposed to sulfuric acid, ammonia/triethylamine, and water vapor sequentially to investigate the alternation in light absorption, morphology and mixing state during simulated atmospheric processing.
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Comportamiento ambiental de lodos de fundición estabilizados/solidificados

Coz Fernández, Alberto 13 July 2001 (has links)
El objetivo de esta tesis ha sido el tratamiento de un residuo (lodo de fundición) procedente del lavado húmedo de los gases del horno fusor. Para ello, se ha evaluado la peligrosidad del residuo y, posteriormente, se han estudiado diferentes tratamientos previos al vertido y se ha realizado su evaluación ambiental. El lodo de fundición es un residuo ecotóxico, debido principalmente a la alta concentración de cinc y a la carga orgánica (fenoles) del mismo, pudiéndose establecer relaciones matemáticas entre la ecotoxicidad y la concentración de cinc y fenoles, tanto en el residuo original como en los productos finales. Entre las diferentes tecnologías de tratamiento, destacan los procesos de estabilización/solidificación con cal o cemento como agente aglomerante, por su elevado interés en residuos de carácter tóxico mixto: orgánico e inorgánico. Se ha llevado a cabo un estudio exhaustivo de los diferentes aditivos utilizados en dichos procesos y se han desarrollado diferentes formulaciones cal o cemento y aditivos/residuo con el fin de cumplir los parámetros ambientales, concluyéndose con la relación existente entre formulación y evaluación ambiental y obteniendo una patente de invención. / The aim of this work has been the study of the treatment of foundry sludge coming from after wet cleaning of gases of the furnace in foundry activities. Previously, the hazardous of the waste material has been evaluated. Later, different treatments have been studied and the environmental evaluation have been conducted. Foundry sludge is an ecotoxical waste due to inorganic (basically zinc) and organic (phenols) pollutants, being able to establish mathematical relationships between the ecotoxicity and the concentration of zinc and phenols, both in waste and end-products. Among the different technologies for the treatment, stabilisation/solidification processes with lime or cement as binders are very interesting technologies for waste of mixed character (organic and inorganic). An exhaustive study of different additives used in these processes has been carried out and different formulations have been developed in order to inertise the waste materials, concluding with the relationships between formulation and environmental evaluation and obtaining a patent.

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