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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.
481

[pt] AVALIAÇÃO QUIMIOMÉTRICA DO COMPORTAMENTO DO MATERIAL PARTICULADO FINO NA ATMOSFERA NO ESTADO DO RIO DE JANEIRO / [en] CHEMOMETRIC EVALUATION OF FINE PARTICULATE MATTER PERFORMANCE ON RIO DE JANEIRO STATE ATMOSPHERE

20 December 2021 (has links)
[pt] As partículas finas (PM2.5) são um dos principais poluentes atmosféricos associados a problemas de saúde. Estas partículas penetram no sistema respiratório, carreando desde metais traços a substâncias orgânicas. Apesar disso, a legislação ambiental brasileira ainda não tem estabelecido padrões para este poluente. Entretanto, Agencia Ambiental dos Estados Unidos (US.EPA) já tem adotado limites para exposições de curto (25 (micro)g m-3/diário) e longo (15 (micro)g m-3/anual) prazo. Esta tese teve quatro principais objetivos: (1) investigar a relação das condições meteorológicas, sazonalidade e bacias aéreas sobre as concentrações de PM2.5 na atmosfera; (2) avaliar modelos de previsão de qualidade do ar inovadores para estimar concentração de PM2.5 em locais com diferentes fontes de emissão; (3) validar método de extração e determinação pseudototal de metais traços presentes no material particulado, com espectrômetro de emissão ótica por plasma indutivamente acoplado (ICP-OES) de acordo com critérios estabelecidos pelo INMETRO; (4) quantificar carbono orgânico e metais traços presentes no material particulado fino para entender melhor como a atmosfera do estado do Rio de Janeiro tem sido afetada, devido aos vários tipos de emissão e condições meteorológicas. Amostradores de grandes volumes coletaram todas as amostras de PM2.5. Estes amostradores foram operados por 24 h, a cada seis dias, em locais com diferentes fontes de emissão (industrial, veicular, poeira do solo, etc.), no estado do Rio de Janeiro. As amostras foram coletadas pelo Instituto Estadual do Ambiente (INEA), no período de janeiro/11 até dezembro/13. Variáveis meteorológicas próximas (d(menor que)2 km) aos pontos de monitoramento de PM2.5 também foram obtidas na mesma frequência e período de amostragem. Em relação a este estudo, quatro resultados podem ser destacados. O primeiro, as concentrações médias diárias de PM2.5 variaram de 1-65 (micro)g m-3, ultrapassando em alguns pontos os limites adotados pela US.EPA. Estes resultados mostraram que concentrações de PM2.5 no RJ não é influenciada, em expressão, pela sazonalidade. Além disso, foi observado que as bacias aéreas definidas no Rio de Janeiro não têm sido confirmadas, e os locais mostraram uma semelhança de comportamento em função da sua fonte de emissão. O segundo, a aplicação do modelo Holt-Winters para previsão de PM2.5 simulou melhor a zona industrial, com RMSE (raiz do erro quadrático médio) entre 5,8-14,9 (micro)g m-3. Em contrapartida, a rede neural artificial associada a variáveis meteorológicas estimou melhor os resultados das zonas urbanas e rurais, com RMSE entre 4,2-9,3 (micro)g m-3. O terceiro, o método de extração e determinação pseudototal de metais por ICP-OES atendeu aos critérios de validação estabelecidos pelo INMETRO. Além disso, mostrou-se ser equivalente ao método US.EPA IO-3.1. Finalmente, as concentrações de carbono orgânico solúvel em água variaram de 0,8-4,9 (micro)g m-3. Os principais metais determinados foram: Na (5,8-13,6 (micro)g m-3), Al (1,6-6,7 (micro)g m-3) e Zn (1,9-6,6 (micro)g m-3). Foi verificado também que os fenômenos meteorológicos de superfície aumentam em 30 por cento a explicação da variância do modelo receptor (PCA), quando adicionados aos dados das substâncias químicas analisadas do PM2.5. Contudo, é crucial a aplicação de ferramentas quimiométricas para ajudar na caracterização e estimava das concentrações de poluentes atmosféricos. / [en] Fine particulate matters (PM2.5) are one of the primary air pollutants associated with health problems. These particles penetrate in the respiratory system, loading from trace metals to organic compounds. Neverthelere4ss, the Brazilian environmental legislation has not yet established standards for this pollutant. However, the US Environmental Agency (US.EPA) has already adopted limits for short-term (25 (micro)g m-3/daily) and long-term (15 (micro)g m-3/annual) exposures. This thesis had four main objectives: (1) to investigate the relation of weather conditions, seasonality and air basins on PM2.5 concentrations in the atmosphere; (2) to evaluate innovative air quality forecast models to estimate PM2.5 concentration in sites with different emission sources; (3) to validate method to extract and pseudo total determinate trace metals present in the particulate matter by inductively coupled plasma optical emission spectrometer (ICP-OES) according to criteria established by INMETRO; (4) to quantify organic carbon and trace metals present in fine particulate matter to better understand how the Rio de Janeiro State (RJ) atmosphere has been affected due to the various types of emission and weather conditions. High volumes samplers PM2.5 collected all PM2.5 samples. These samplers were operated for 24 h, every six days, in places with different emission sources (industrial, vehicular, soil dust, et caetera), in the Rio de Janeiro State. The samples were collected by the State Environmental Institute (INEA) during the period from January/2011 still December/2013. Meteorological variables nearby (d(less than)2 km) to PM2.5 monitoring points were also obtained at the same frequency and sampling period. Regarding this study, four results can be highlighted. The first one, the PM2.5 dailly concentrations average ranged from 1-65 (micro)g m-3, exceeding in some sites the limits adopted by US.EPA. These results showed that PM2.5 concentrations in RJ is not influenced, in expression, by the seasonality. In addition, it was observed that the defined RJ air basins have not been confirmed, and the local showed a similar performance according to their emission sources. The second one, the application of the Holt-Winters model for PM2.5 forecast simulated best industrial zone, with RMSE (root mean square error) between 5.8 to 14.9 (micro)g m-3. On the others hand, the artificial neural network associated with meteorological variables estimated best results from urban and rural areas, with RMSE between 4.2 to 9.3 (micro)g m-3. The third one, the method to extract and determine pseudo total metals by ICP-OES followed the validation criteria established by INMETRO. Furthermore, it was shown to be equivalent to US.EPA IO-3.1 method. Finally, the water-soluble organic carbon concentrations ranged from 0.8 to 4.9 (micro)g m-3. The principal metals determined were: Na (5.8-13.6 (micro)g m-3), Al (1.6-6.7 (micro)g m-3) and Zn (1.9-6.6 (micro)g m-3). It was also found that the surface meteorological phenomena increase at 30 percent the explicated variance of the receiver model (PCA) when added to PM2.5 chemical analysis data. Therefore, it is crucial the application of chemometric tools to help in the characterization and estimated air pollutant concentrations.
482

Účinky hospodaření s půdou na kvalitu půdy v blízkosti obce Šardičky / Effects of soil management on soil quality near Šardičky village

Schneiderová, Šárka January 2019 (has links)
This diploma thesis is focused on influence of reduced tillage technology of soil processing on it´s near-surface soil layer (0 to 10 cm). The research was carried out on agricultural land near Šardičky village, where company ZEMO spol. s r.o. provides long-term use of reduced tillage technology. In 2016 the soil quality in this site was evaluated by using physical and hydrophysical parameters, results are presented in the previous bachelor thesis "Selected hydrophysical parameters as indicators of soil quality.". In diploma thesis in addition chemical and other hydrophysical properties have been evaluated to provide a comprehensive assessment of soil quality. In 2016, poppy seed was grown on this site and spring barley was grown in 2017 and 2018. Grab samples and intact soil cores were taken during the vegetation period of the crop. After three years of experimental research, in which I participated, it is possible to assess the development of individual parameters and the influence of reduced tillage technology on near-surface soil layer. The theoretical part of the diploma thesis deals with the description of the reduced tillage technology and problematics of the determination of soil parameters, which are used for evaluation of the quality of the near-surface layer. The practical part deals with evaluation of these parameters according to various authors and describes the development of soil quality during years 2016, 2017 and 2018.
483

Padan 95 SP treatment by electrochemical process and its combination with other techniques

Nguyen Tien, Hoang 06 November 2019 (has links)
This dissertation describes electrochemical oxidation of Padan 95 SP on Boron-doped diamond (BDD) electrode mainly by •OH radicals (which was measured by indirect method, i.e: the formation of 2-Hydroxylterephthalic acid (2-HTA)), Electro-Fenton and the combination with adsorption technology for increasing total organic carbon (TOC) removal efficiency. In this study, the formation of 2-HTA on BDD electrode via the reaction between terephthalic acid (TA) and •OH as a method to quantify hydroxyl radical formation was investigated. The degradation of Cartap in Padan 95SP (95 % Cartap) on BDD was investigated. Operating parameters such as applied current density, types of electrolyte and initial concentration of Padan 95SP were varied in order to determine their effect on the degradation efficiency of Cartap. The concentration of Cartap was determined by UV-Vis spectroscopy according to 5,5-Dithiobis-(2-nitrobenzoic acid) (DTNB) procedure. High Performance Liquid Chromatography (HPLC) and Gas Chromatography/Mass Spectrometry (GC-MS) were used to characterize the commercial Padan 95SP and the formation of by-products. The optimal conditions for Cartap degradation by electrochemical process have been established: concentration of electrolyte: 0.05 M Na2SO4, initial concentration of Padan 95SP: 300 mg·L-1, pH = 3, current density: j = 20 mA·cm-2. At this condition, Cartap decreases to 41 %, TOC decay reaches 8 %. To increase TOC decay at higher Padan 95 SP concentration in aqueous solution, the combination technique of electrochemical process with other techniques was proposed, e.g.: Electro-Fenton technique, pre-oxidizing by NaOCl or the Electro-Adsorption combination. In the Electro-Fenton technique, we investigated the influence of factors such as the presence of NaOCl in pretreatment of process, affects of H2O2 concentration, Fe2+ dosage, co-catalysts metals ion and pH. The efficiency shows approximately 80 % of TOC removed at 700 mg·L-1 Padan 95 SP. The combination of electrochemical with adsorption method shows the efficient removals of TOC and Padan 95SP (95 % Cartap) based on reagents oxidation in electrochemical process and adsorption of granular activated carbon (GAC), respectively. The influence of factors such as supporting electrolytes, flow rate, bed height, recycling number as well as initial concentration were investigated in order to determine their effects on TOC removal. The efficiency of this combination shows approximately 75 % of TOC and more than 90 % of Cartap removed at 700 mg·L-1 Padan 95 SP. Fourier Transform Infrared (FT-IR) and (Brunauer–Emmett–Teller) BET surface analysis were applied to investigate GAC before and after usage. The results have shown that the application of electrochemical technique with other methods can be the potential option for treatment of wastewater containing Padan 95 SP. / Diese Dissertation befasst sich mit der Reduktion des gesamten organischen Kohlenstoffs (TOC) aus wässriger Lösung, die Padan 95 SP enthält. Als Methoden zur Minimierung von TOC wurden die elektrochemische Oxidation von Padan 95 SP auf Bor-dotierter Diamant (BDD) Elektroden durch •OH Radikale, Elektro-Fenton und die Kombination mit Adsorptionstechnologien verwendet. Die •OH Radikale wurden dabei durch indirekte Methoden, z. B. die Bildung von 2-HTA gemessen. Zur Quantifizierung der Hydroxylradikalbildung wurde in dieser Studie die Bildung von 2-Hydroxylterephthalsäure (2-HTA) an BDD-Elektroden über die Reaktion zwischen Terephthalsäure (TA) und •OH untersucht. Weiterhin befasst sich die Arbeit mit dem Abbau von Cartap in Padan 95SP (95% Cartap) auf BDD über die Reaktion zwischen Cartap und Hydroxylradikalen. Betriebsparameter wie die angewandte Stromdichte, die Elektrolytarten und die Anfangskonzentration von Padan 95SP wurden variiert, um ihre Wirkung auf die Abbaueffizienz von Cartap zu bestimmen. Die Konzentration von Cartap wurde mittels UV-Vis-Spektroskopie mit dem 5,5-Dithiobis-(2-Nitrobenzoesäure) (DTNB) Verfahren bestimmt. Hochleistungs-Flüssigkeitschromatographie (HPLC) und Gaschromatographie/Massenspektrometrie (GC-MS) wurden verwendet, um das kommerziell erhältliche Padan 95SP und die Bildung von Nebenprodukten beim Abbau von Cartap zu charakterisieren. Die optimalen Bedingungen für die Cartap-Degradation durch den elektrochemischen Prozess wurden festgelegt: Konzentration des Elektrolyten: 0.05 M Na2SO4, Padan 95SP Anfangskonzentration: 300 mg·L-1, pH = 3, Stromdichte: j = 20 mA·cm-2. Unter diesen Bedingungen sinkt Cartap auf 41% und der TOC erreicht 8 % des jeweiligen Ausgangswertes. Um den TOC-Zerfall bei höher Padan 95 SP Konzentration in Wasser zu erhöhen, wurde die Kombination des elektrochemischen Prozesses mit anderen Techniken vorgeschlagen, z.B.: Elektro-Fenton-Technik, Oxidation mit NaOCl, oder die Kombination des elektrochemischen Prozesses mit einem Adsorptionsprozess. Bei der Elektro-Fenton-Technik wurde der Einfluss von Faktoren wieder Anwesenheit von NaOCl in der Prozessvorbehandlung, Auswirkungen der H2O2-Konzentration, Fe2+-Dosierung, Metallionen als Cokatalysatoren und der pH-Wert der Lösung untersucht, um die Wirkung auf die Abbau-Effizienz für Cartap zu bestimmen. Es konnten mit dieser Methode rund 80 % TOC, ausgehend von 700 mg·L-1Padan 95SP, entfernt werden. Die Kombination des elektrochemischen Prozesses mit einer Adsorptionsmethode ermöglicht eine effiziente Entfernung von TOC und Padan 95SP (95% Cartap). Dies basiert auf der Oxidation und anschließender Adsorption auf granularer Aktivkohle (GAC). Der Einfluss von Faktoren wie Leitelektrolyten, Flussrate, Betthöhe, Recyclingzahl sowie die Anfangskonzentration von Padan 95 SP wurde untersucht, um deren Auswirkungen auf die TOC Entfernung zu bestimmen. Durch die Kombination konnten so 75% desTOC und mehr als 90% Cartap bei 700 mg·L-1Padan 95 SP entfernt werden. Fourier-Transformations-Infrarot (FT-IR) und BET-Oberflächenanalyse wurden angewendet, um GAC vor und nach der Verwendung zu untersuchen. Die Ergebnisse haben gezeigt, dass die Kombination des elektrochemischen Prozesses mit anderen Methoden eine potentielle Option für die Behandlung von Abwasser, das Padan 95 SP enthält, sein kann.
484

Determining the effects of elevated carbon dioxide on soil acidification, cation depletion, and soil inorganic carbon and mapping soil carbons using artificial intelligence

Ferdush, Jannatul 09 August 2022 (has links) (PDF)
Soil carbon is the largest sink and source of the global carbon cycle and is disturbed by several natural, anthropogenic, and environmental factors. The global increase of atmospheric CO2 affects soil carbon cycling through varied biogeochemical processes. The first chapter is a compilation of current information on potential factors triggering soil acidification and weathering mechanisms under elevated CO2 and their consequences on soil inorganic carbon (SIC) pool and quality. Soil water content and precipitation were critical factors influencing elevated CO2 effects on the SIC pool. The second chapter examines a detailed column experiment in which six soils from the state of Mississippi, USA, representing acidic, neutral, and alkaline pH, were exposed to different CO2 enrichments (100%, 10%, and 1%) for 30 days. The leachates’ pH tended to attain an equilibrium state (neutral) with time under CO2 saturation. SIC increased under CO2 saturation, whereas cation exchange capacity (CEC) showed a decreasing pattern in all soils. In the third chapter, an eXplainable artificial intelligence (XAI) was performed to visualize the different forms of soil carbon variability across the Mississippi River Basin area. This model explains key insights and local discrepancies, suggesting a solution to the “Black-Box” issue. The best performing model, stack ensemble, showed improved RMSE (3 to 8%) and spatial variability for soil carbons than other ML models, especially after adding the residuals from regression analyses. Land cover type > soil pH > total nitrogen, > NDVI were identified as the top four crucial factors for predicting SOC when bulk density > precipitation, soil pH > mean annual temperature described SIC. The proposed automatic machine learning (AutoML) model with model agnostic interpolations might be a hallmark to mitigate the C loss under adverse climate change conditions and allow diverse knowledge groups to adopt a new interpretable ML algorithm more confidently. Findings from this study help predict the impact of elevated atmospheric CO2 on soil pH, acidification, and nutrient availability and develop strategies for sustainable land management practices under a changing climate.
485

Impact of topsoil depth and amendment application on soil health and agronomic productivity in central Ohio

Moonilall, Nall Inshan January 2022 (has links)
No description available.
486

Carbon Dynamics of Subtropical Wetland Communities in South Florida

Villa Betancur, Jorge Andres 06 June 2014 (has links)
No description available.
487

Carbon Sequestration By Home Lawn Turfgrass Development and Maintenance in Diverse Climatic Regions of the United States

Selhorst, Adam Louis 25 July 2011 (has links)
No description available.
488

Temporal Analysis of Precipitation and Brownification in Lake Bolmen.

Babu, Merin January 2024 (has links)
This thesis investigates brownification in Lake Bolmen, Sweden, focusing on the precipitation's effect on water colouration in 3 tributaries to the lake. This study uses long-term meteorological data from the Swedish Meteorological and Hydrological Institute (SMHI) and the water samples collected over more than one year from Lake Bolmen and its three major tributaries Storån, Lillån, and Önnekvarn. Water colour was measured using spectrophotometric techniques. The key findings show a significant positive link between the amount of precipitation per month and water colour, used as a proxy for dissolved organic carbon. The study found that monthly precipitation did not show an immediate effect, but rather that the effect of precipitation on colour was visible with one-month delay. The study finds significant geographical variability in brownification intensity across different streams, indicating that localised effects are also important. The study highlights the crucial role of environmental factors in the organic matter movement and the necessity for specific conservation measures to reduce the negative effects of brownification on water quality. To develop effective Lake Bolmen management techniques, recommendations include continual monitoring and a multidisciplinary approach. This study advances our understanding of the dynamic interplay between freshwater ecosystems hydrology, meteorological, and organic matter processes.
489

From impact to resource

Hansen, Anja 17 May 2017 (has links)
Energie und Rohstoffe auf Basis von Biomasse gelten als wichtiger Beitrag, um den anthropogen begründeten Klimawandel zu mindern. Diese publikationsbasierte Arbeit analysiert, inwiefern Aussagen über Vorzüglichkeit von Biomassenutzung im direkten Vergleich oder auch in komplexeren wirtschaftlichen Nutzungssystemen durch Unsicherheiten in den Treibhausgasemissionen (THG) oder durch die Anwendung der Bewertungsmethodik beeinflusst werden. Eine Fallstudie zur stationären Biostromerzeugung aus der Vergasung von Pappelhackschnitzeln zeigte mittels Monte-Carlo-Analyse, dass dieser Biostrom trotz Unsicherheiten weniger THG emittiert bzw. sogar Kohlendioxid sequestrieren könnte. Die zweite Fallstudie analysierte Biomassenutzung im Systemzusammenhang. Sie bezog neben THG-Emissionen als Bewertungskriterien sowohl den Bedarf an Agrarfläche als auch an fossilen Ressourcen mit ein. Für das Beispiel der Häuserdämmung mittels Hanffasern oder Styropor konnte aus den drei Kriterien auch unter Berücksichtigung mehrerer Szenarien keine eindeutige Vorzugslösung der Biomassenutzung abgeleitet werden. Basierend auf dem Produktivitätskonzept stellt der dritte Beitrag mit CUDe (Carbon Utilization Degree) einen Ansatz vor, wie die Nutzungseffizienz des in der Biomasse bereitgestellten Kohlenstoffs bewertet werden könnte. THG-Minderungsrechnungen erfordern eine fundierte Kenntnis der Methode als auch des Produktionssystems in seinem regionalen Kontext. Als Landnutzungseffekte sollten neben Änderungen im Bodenkohlenstoffgehalt auch Unterschiede in Lachgas-Hintergrundemissionen von annuellen gegenüber mehrjährigen Kulturen berücksichtigt werden. Trade-Offs sprechen dafür, Biomassenutzungssysteme nicht nur hinsichtlich Klimawirksamkeit zu optimieren. Ergänzend könnte Kohlenstoff auch als Ressource betrachtet und mit Effizienzkriterien bewertet werden. Biomassenutzung ließe sich so optimieren, dass gemeinsam mit Klimaschutz weitere aktuelle Handlungsfelder adressiert werden. / Biomass-based energy and materials are considered important for the mitigation of human-induced climate change and as relevant bioeconomic feedstock. This publication-based dissertation aims to contribute to the discussion about the reliability of mitigation assessment of biomass applications in an increasingly bio-based, low-carbon economy that also fulfils sustainability constraints of resource conservation. It analysed how preference of biomass use in direct comparison as well as in larger economic context is affected by single uncertainties as well as by mitigation calculation methods. A case study on stationary bioelectricity generation from poplar wood chip gasification with a Monte Carlo approach showed that such bioelectricity could emit less greenhouse gases (GHG) or even sequester carbon despite existing uncertainties. The second case study analysed biomass use in a systemic context. Besides GHG emissions also resource demand of cropland and fossil fuels were used to assess two strategies to isolate buildings. From the three criteria, none of the strategies would clearly be preferred. The third case study presented an approach to assess the efficiency of biomass carbon use (CUDe; Carbon Utilization Degree) and applied it exemplarily to a biogas and a hemp insulation system. GHG mitigation analyses of biomass use must be performed with profound knowledge of the methodology and the biomass system in its regional context. In land use change assessment, emissions resulting from deviating nitrous oxide baselines from annual and perennial crops should be considered in addition to carbon stock changes. Optimization of biomass applications only with respect to GHG emissions (or other single criteria) might overlook trade-offs. However, multi-criteria analyses might yield ambiguous results. A resource-efficient viewpoint on biogenic carbon use instead of its sole GHG implications might help to foster a transformation to bio-based, low-carbon economies.
490

化学・同位体組成及び光学特性による溶存有機物のキャラクタリゼーション

吉岡, 崇仁 03 1900 (has links)
科学研究費補助金 研究種目:基盤研究(C)(2) 課題番号:10640474 研究代表者:吉岡 崇仁 研究期間:1998-1999年度

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