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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.
11

Assessment of the Potential for Geological Storage of Carbon Dioxide in Cambodia / カンボジアにおける二酸化炭素地中貯留の可能性に対する評価

Mao Chanrithyrouth 24 September 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18570号 / 工博第3931号 / 新制||工||1604(附属図書館) / 31470 / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 松岡 俊文, 教授 小池 克明, 准教授 岸田 潔 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM
12

A Descriptive Study of Grain Production, Consumption, and Storage in Virginia

Caffarelli, Peter Anthony 20 January 2016 (has links)
Agriculture is an important industry in Virginia, with an array of crops grown and animals produced. Virginia's crop, livestock, and poultry sectors sold agricultural products worth $1.4 billion and $2.4 billion, respectively, in 2012. One of the products, grain, serves as an important input for raising livestock and poultry. Virginia needs to import grain from other states (Eastern Corn Belt states) to meet current livestock feed requirements, an expense that raises the cost of production over locally sourced grains . Further, such movements of grain from producing-areas to demand-areas rely on the efficient and timely interaction of grain storage and transportation. Describing the details of the grain supply chain provides insights into the interplay and relationships among production, storage, transportation, and end users of grains and oilseeds in Virginia. Results of a state-wide survey of Virginia grain producers shed light on the following topics: current cropping practices; current grain storage practices; available farm-level storage and its use, age, and expected life; and future storage plans and constraints. Overall findings include, grain production in Virginia has generally increased over the last decade, yet storage capacity remains constant and continues to age; livestock and poultry populations are declining leading to less demand for feed grains and oilseeds; grain farmers report satisfaction with their current storage situation and higher returns to stored grain may encourage "non-storers" to build storage; and the majority the grain leaving the farm is hauled by truck over short distances (25 miles or less). Overall, the results provide a foundation for understanding the grain supply chain in Virginia and offer useful information to Virginia's agricultural stakeholders. / Master of Science
13

Assessment of the Geological Storage Potential of Carbon Dioxide in the Mid-Atlantic Seaboard: Focus on the Outer Continental Shelf of North Carolina

Mullendore, Marina Anita Jacqueline 02 May 2019 (has links)
In an effort to mitigate carbon dioxide (CO2) emissions in the atmosphere, the Southeast Offshore Storage Resource Assessment (SOSRA) project has for objective to identify geological targets for CO2 storage in two main areas: the eastern part of the Gulf of Mexico and the Atlantic Ocean subsurface. SOSRA's second objective is to estimate the geological targets' capacity to store up to 30 million metric tons of CO2 each year with an error margin of ±30%. As part of this project, the research presented here focuses on the outer continental shelf of North Carolina and its potential for the deployment of large-scale offshore carbon storage in the near future. To identify geological targets, workflow followed typical early oil and gas exploration protocols: collecting existing datasets, selecting the most applicable datasets for reservoir exploration, and interpreting datasets to build a comprehensive regional geological framework of the subsurface of the outer continental shelf. The geomodel obtained can then be used to conduct static volumetric calculations estimating the storage capacity of each identified target. Numerous uncertainties regarding the geomodel were attributed to the variable coverage and quality of the geological and geophysical data. To address these uncertainties and quantify their potential impact on the storage capacity estimations, dynamic volumetric calculations (reservoir simulations) were conducted. Results have shown that, in this area, both Upper and Lower Cretaceous Formations have the potential to store large amounts of CO2 (in the gigatons range). However, sensitivity analysis highlighted the need to collect more data to refine the geomodel and thereby reduce the uncertainties related to the presence, dimensions and characteristics of potential reservoirs and seals. Reducing these uncertainties could lead to more accurate storage capacity estimations. Adequate injection strategies could then be developed based on robust knowledge of this area, thus increasing the probability of success for carbon capture and storage (CCS) offshore projects in North Carolina's outer continental shelf. / Doctor of Philosophy / Since the industrial revolution, a significant increase in the anthropogenic emissions of greenhouse gases has been observed worldwide. The rise in concentration of these gases in the atmosphere, specifically carbon dioxide (CO₂), has been linked to an increase in the average temperature on Earth, what is commonly known as global warming. To mitigate the emission of anthropogenic CO₂ in the atmosphere and consequently limit its impact on Earth’s climate, Carbon Capture and Storage projects (CCS) have been developed on various scales. In this type of project, CO₂ is captured from an emitting source (e.g., power plants), then transported via pipelines and stored in deep geological formations. In the United States, onshore CCS projects have demonstrated the technical feasibility of such projects. However, controversies associated with public acceptance and mineral ownership make expansive onshore CCS project development complicated. For these reasons, the U.S. Department of Energy (DOE) has been investigating offshore locations for the deployment of large-scale CCS projects. Southeast Offshore Storage Resource Assessment (SOSRA) is a project sponsored by the U.S. DOE to assess the storage potential of the eastern part of the Gulf of Mexico and the Atlantic Ocean as a first step towards the development of large-scale offshore storage of CO₂. The state of North Carolina was identified as an adequate candidate for CO₂ offshore storage due to its location on the Atlantic coast and its elevated CO₂ emissions from the power plants on its coastal plains. However, as exploration conducted on the outer continental shelf of North Carolina has been minimal, published information regarding the subsurface of this area remains limited to this date. To ensure the safe, long-term storage of CO₂ in this area, an extensive study was needed to select suitable geological formations and determine the storage capacity of each identified target. The research described here aimed to identify such geological targets and estimate the CO₂ storage capacity of North Carolina’s outer continental shelf
14

Synthesis, Structure And Redox Catalytic Properties Of Pt And Pd Ion Substituted Ce1-xMxO2(M= Ti, Zr & Hf) Oxygen Storage Capacity Nano-materials

Baidya, Tinku 11 1900 (has links)
Three-way catalysis (TWC) involves simultaneous removal of the three pollutants (i.e., CO, NOx, and HCs) which led to the branch of auto-exhaust catalysis. CeO2 has become the main component of TWC catalyst because of its oxygen storage storage (OSC) property to supply oxygen under excess fuel condition and store oxygen under lean condition. Substitution of smaller isovalent cations like Ti4+, Zr4+ and Hf4+ ions in CeO2 forming Ce1-xMxO2 (M = Ti, Zr &Hf) solid solution enhance the OSC property. XRD along with EXAFS study showed that cations arrange in FCC lattice but oxygen coordination around metal ions is split into 4 + 4 coordination in Ce1-xMxO2 instead of ideal 8 coordination in CeO2. The longer Ce/Ti/Zr – O bonds are weakly bound and can be easily removed by H2 giving high OSC value than pure CeO2. Among the three OSC systems studied here, Ce0.5Zr0.5O2 showed exceptionally high OSC which lead to formation of a new a pyrochlore, Ce2Zr2O6.3. This compound is nearly metallic. Ce0.85-xTi0.15PtxO2- (x = 0.01 & 0.02) crystallizes in fluorite structure and Pt is ionically substituted with 2+ and 4+ oxidation states. H/Pt atomic ratio at 30 oC over Ce0.84Ti0.15Pt0.01O2- is 5 and over Ce0.99Pt0.01O2-δ is 4 against just 0.078 for 8 nm Pt metal particles. Carbon monoxide and hydrocarbon oxidation activity are much higher over Ce1-x-yTixPtyO2 (x= 0.15, y= 0.01, 0.02) compared to Ce1-xPtxO2 (x= 0.01, 0.02). Synergistic involvement of Pt2+/Pt0 and Ti4+/Ti3+ redox couples in addition to Ce4+/Ce3+ due to the overlap of Pt(5d), Ti(3d), and Ce(4f) bands near EF is shown to be responsible for enhanced redox property and higher catalytic activity. On substitution of Pd ion in Ce1-xTixO2, more lattice oxygen is found to be more labile than Pd in CeO2. The easy removal of oxygen from the more reducible Ti4+ containing support plays a major role in showing higher catalytic activity of this material for CO oxidation, N2O and NO reduction by CO. The catalyst shows 100% N2 selectivity  240 oC in NO+CO reaction. It has been shown that oxide ion vacancy creation created by removal of lattice oxygen by CO is responsible for dissociation of NO or N2O at a lower temperature. Ionicity of Pd2+ ion in different support could be varied by varying the ionicity of the oxide support itself. Rates of CO oxidation increases or activation energy decreases over Ce1-xPdxO2-δ, Ti1-xPdxO2-δ and Ce1-x-yMxPdyO2-δ (M = Ti, Zr, Hf ; x = 0.25, 0.4 ; y = 0.02) is increased with ionicity of Pd2+ ion. The substitution of Sn in CeO2 forming Ce1-xSnxO2 (x = 0.1-0.5) solid solution was prepared using tin oxalate precursor by solution combustion method. These oxides can be promising support for noble metals because of the Sn4+  Sn2+ redox couple in addition to Ce3+/Ce4+. The two electron process involved in the redox reaction of Sn as well as easy reducibility of Sn4+ to Sn2+ offers a far better redox catalytic system hitherto not reported. Ce1-xSnxO2 solid solutions as well as Pd ion substituted Ce1-xSnxO2 was prepared for the first time.
15

Impact des hétérogénéités sédimentaires sur le stockage géologique du CO2

Issautier, Benoit 20 December 2011 (has links)
La démarche d’intégration des hétérogénéités dans les modèles réservoirs en est à ses prémices dans le domaine du stockage géologique de CO2. C’est dans ce contexte que s’inscrivent ces travaux de thèse. Un protocole d’analyse depuis l’étude de terrain jusqu’aux simulations réservoirs a été établi. La caractérisation du Minjur Sandstone (formation Triasique d’Arabie Centrale) met en avant le caractère crucial de la connectivité des corps dans l’architecture du réservoir, notamment en liant génétiquement leur nature, leur connectivité et leur position dans la séquence de dépôt. S’appuyant sur la connaissance de cette formation, un modèle conceptuel est construit, puis reproduit stochastiquement par un algorithme permettant l’élaboration de modèles conditionnés par une histoire sédimentaire. Le protocole prévoit la création de 50 scénarios illustrant divers degrés de connectivité ; chaque scénario étant composé de deux modèles de même architecture mais à remplissage sédimentaire différent. Cette approche permet d’appréhender (a) l’impact de la connectivité et (b) des hétérogénéités sédimentaires sur les performances réservoirs. L’estimation de capacité par l’approche statique des volumes disponibles estime une capacité moyenne d’environ 13Mt (aquifère semi-infini de 25 km par 25 km et 60m d’épaisseur à 1000 m de profondeur). Les hétérogénéités internes (sédiments argileux appelés oxbow lakes) entraînent une différence de capacité de 30%. Les simulations dynamiques confirment ces résultats et révèle une variabilité de capacité de 23% liée la connectivité des corps. De plus les hétérogénéités réduisent la migration verticale du gaz ce qui peut augmenter l’intégrité du stockage. / In the CO2 storage context, heterogeneity has only been rarely considered in reservoir models to date. To address this key issue, the project aims at developing a workflow that manages the heterogeneity from the field observations up to the reservoir simulation. The characterisation of the Minjur Sandstone (a Triassic formation from Central Saudi Arabia) shows the crucial role of connectivity in the reservoir architecture, and the genetic link between the nature, location and connectivity of the sedimentary bodies in the sequence. Stemming from this study, a conceptual model was established and stochastically reproduced through an algorithm simulating models conditioned to a sedimentary history. Fifty scenarios were simulated, representing various connectivity degrees. Each of these scenarios is composed of two models, identical by their architecture but different in their internal sedimentary fill. This approach allows the study of the impact of the (a) reservoir bodies’ connectivity and (b) their internal sedimentary heterogeneity on the reservoir’s performances. The capacity estimates using a static calculation based on the available pore volumes reveals a mean capacity of 13 Mt (for a 25 x 25 km x 60 m semi finite aquifer at 1000m deep). The sedimentary heterogeneity (shaly deposits called oxbow lakes) is responsible for a 30% difference of capacity. The flow simulations confirm these results and show that the connectivity of the reservoir bodies creates a 23% capacity variation. Moreover, the heterogeneities tend to reduce the amount of CO2 able to reach the uppermost reservoir which may enhance the storage integrity.
16

Invento para determinação da interceptação de chuva pela serrapilheira em ecossistemas florestais / Device to measure rainfall interception by the forest litter on forest ecosystems

Rosalem, Lívia Malacarne Pinheiro 29 March 2017 (has links)
A serrapilheira é compreendida como a camada acima do solo formada a partir de materiais que caem da vegetação, funcionando como um mecanismo de interceptação da chuva. Apesar do processo de interceptação ser significativo em áreas de florestas, geralmente esse processo é subestimado ou mesmo negligenciado em modelos hidrológicos, justificado pela dificuldade na obtenção desses dados. Este projeto propôs o desenvolvimento de um equipamento que permite realizar medidas em campo da interceptação da serrapilheira em área de cerrado sensu stricto. Com o equipamento desenvolvido, LID (Litter Interception Device), são realizadas medidas do volume de água retido na serrapilheira e do volume que passa pela serrapilheira, atingindo o solo. O LID foi testado e calibrado em laboratório utilizando chuva simulada de três diferentes intensidades sobre o equipamento, contendo três quantidades diferentes de serrapilheira, 2,97, 1,45 e 0,60 kg.m-2. As amostras de serrapilheira utilizadas nos testes foram retiradas de uma área experimental de mata nativa de cerrado sensu stricto, localizada no município de Itirapina, Estado de São Paulo. As intensidades utilizadas foram definidas a partir de uma curva Intensidade-Duração-Frequência (IDF) gerada para a área experimental. Além do bom funcionamento do LID, os testes serviram para determinar os parâmetros Cmax e Cmin (capacidade máxima e capacidade mínima de armazenamento, respectivamente) da serrapilheira do cerrado sensu stricto. Os resultados mostraram que com o LID são realizadas medições da taxa de retenção de água na serrapilheira (mm.min-1), bem como de sua evaporação (mm.min-1) com precisão. Os testes para calibração do pluviógrafo revelaram que as medidas eram sempre subestimadas, necessitando utilizar uma curva de calibração (R2 = 0,99) para corrigir os registros da intensidade que passa para o pluviógrafo. Os valores encontrados para os parâmetros Cmax (1,0 a 3,07 mm) e Cmin (0,78 a 2,27 mm) corroboram com os encontrados por outros autores para a serrapilheira de diferentes florestas. Verificou-se que a variável quantidade de serrapilheira (kg) influencia mais nesses valores, do que a intensidade da chuva (mm.h-1). Conclui-se com os resultados que o LID pode ser utilizado em estudos que pretendam analisar o papel da serrapilheira em processos hidrológicos, sejam estes para a determinação da interceptação da chuva em campo, ou mesmo na determinação de parâmetros em laboratório. / Forest litter is the layer above the ground of the forest formed by materials that fall from the vegetation itself. The vegetation materials are through various stages of decomposition, functioning as a mechanism of rainfall interception. Although the interception process is significant in forested areas, this process is usually underestimated or even neglected in hydrological models due to the difficulties on obtaining these data. We proposed the development of a device that allows the field measurements of the forest litter interception in a cerrado sensu stricto area. The Litter Interception Device (LID), was tested and calibrated in the laboratory. We used simulated rainfall with three different intensities to test the device and also three different amounts of litter, 0.100, 0.230 and 0.470 kg. The litter samples used in the tests were taken from an experimental area of cerrado sensu stricto located in Itirapina, State of São Paulo, Brazil. The intensities of simulated rainfall were obtained from an Intensity-Duration-Frequency (IDF) curve made for the experimental area. Besides the LID functioning tests, the device was tested to determine the parameters Cmax and Cmin (maximum capacity and minimum storage capacity, respectively) of the cerrado sensu stricto forest litter. The results showed that the LID allows measurements of the volume of water retained in the forest litter (mm.min-1) as well as its evaporation (mm.min-1). The pluviometer calibration tests revealed that the measurements were always underestimated, requiring a calibration curve (R2 = 0.99) to correct the volume records that flow to the tipping bucket pluviometer. The values found for Cmax (1.0 - 3.07 mm) and Cmin (0.78 - 2.27 mm) are according with those found by other authors for different kinds of forest litters. It was verified that the variation in the amount of forest litter (kg) influenced more in these values, than the rainfall intensity (mm.min-1) . We concluded that the LID can be used in studies that intend to analyze the role of the forest litter in hydrological processes, whether they area for the determination of the interception of rain in the field or even and in laboratory studies to determine interception parameters of forest litter.
17

Avaliação do desempenho hidrológico de pavimentos permeáveis / Evaluation of the hydrologic performance of permeable pavements

Guedes, Cláudia de Sousa 12 March 2015 (has links)
Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2016-02-05T08:37:29Z No. of bitstreams: 2 Dissertação - Cláudia de Sousa Guedes - 2015.pdf: 10944316 bytes, checksum: eb54cff6fee4c1a5927f502848b16acc (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-02-05T08:43:12Z (GMT) No. of bitstreams: 2 Dissertação - Cláudia de Sousa Guedes - 2015.pdf: 10944316 bytes, checksum: eb54cff6fee4c1a5927f502848b16acc (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-02-05T08:43:12Z (GMT). No. of bitstreams: 2 Dissertação - Cláudia de Sousa Guedes - 2015.pdf: 10944316 bytes, checksum: eb54cff6fee4c1a5927f502848b16acc (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-03-12 / This study evaluated the performance of permeable pavements with coatings the type Paver, Porous and Concregrama under different basic conditions in order to control runoff at the source. Were simulated by means of a simulated rainfall, the rain event intensity 100.80 mm/h with a duration of 30 minutes and 64.20 mm/h for 60 minutes, on the floor constructed in three different structural conditions. The stretch I with 15 cm storage layer, the stretch II with 7 cm and the stretch III with only 4 cm. The tests were performed in duplicate and all simulations were performed 36. The pavements were evaluated for the generation runoff, storage and retention of the flow. The nine permeable pavements evaluated in this study allowed a reduction of more than 50% of the runoff and the delay on average 17 minutes runoff, as well as the temporary storage of rainwater. In terms of coefficient C, the structure that presented the best hydrologic performance was the stretch I, the results varied from 0 to 0.20. Only pavements with Paver coating showed runoff. / Neste trabalho foi avaliado o desempenho de pavimentos permeáveis com revestimentos do tipo Paver, Poroso e Concregrama sob diferentes condições de base, com vista no controle de escoamento superficial na fonte. Foram simulados, por meio de um simulador de chuva, eventos de chuva de intensidade de 100,80 mm/h com duração de 30 minutos e 64,20 mm/h e duração de 60 minutos, sobre os pavimentos construídos em três condições estruturais diferentes. O trecho I com 15 cm de camada de armazenamento, o trecho II com 7 cm e o trecho III com apenas 4 cm. Os ensaios foram feitos em duplicata e ao todo foram realizadas 36 simulações. Os pavimentos foram avaliados quanto à geração de escoamento, armazenamento e retenção do escoamento. Os nove pavimentos permeáveis avaliados nesta pesquisa permitiram a redução de mais de 50% do escoamento superficial e o retardo em média de 17 minutos do escoamento superficial, bem como o armazenamento temporário das águas pluviais. Em termos de coeficiente C, a estrutura que apresentou o melhor desempenho hidrológico foi o trecho I, cujos resultados variaram de 0 a 0,20. Apenas pavimentos com o revestimento Paver apresentaram escoamento superficial.
18

Vliv oxidačního stupně aktivní podložky na reaktivitu přechodových kovů / Reactivity of transition metals - influence of the degree of oxidation of active substrate

Kettner, Miroslav January 2017 (has links)
The impacts of fluorine doping of ceria are studied by means of surface science experimental methods. Fluorine-doped and fluorine-free ceria layers are epitaxially grown on rhodium single crystals and their properties are compared in regular and inverse catalyst configurations. A procedure for epitaxial growth of CeO2(110) and CeOxFy(110) layers on Rh(110) single crystal is developed and described in detail. Shape alterations of Ce 3d spectrum brought about by fluorine doping are explained and a suitable deconvolution method is proposed. Special attention is focused towards stability of fluorine in ceria. Presented data show that fluorine incorporation in ceria lattice causes stable reduction of ceria, which withstands up to 200řC in near-ambient pressure conditions. Morphological changes are observed due to elongation of surface lattice constant of reduced ceria. Oxygen storage capacities and hydrogen oxidation reaction rates of four different studied systems are compared and discussed. The twofold nature of oxygen exposure of fluorinated ceria is discovered and explained. Oxygen repels fluorine from the surface, while the remaining part of fluorine is expelled to adsorbate positions, where its electronic state is altered. Moreover, such fluorine is prone to interact with atomic hydrogen. This reaction is...
19

Invento para determinação da interceptação de chuva pela serrapilheira em ecossistemas florestais / Device to measure rainfall interception by the forest litter on forest ecosystems

Lívia Malacarne Pinheiro Rosalem 29 March 2017 (has links)
A serrapilheira é compreendida como a camada acima do solo formada a partir de materiais que caem da vegetação, funcionando como um mecanismo de interceptação da chuva. Apesar do processo de interceptação ser significativo em áreas de florestas, geralmente esse processo é subestimado ou mesmo negligenciado em modelos hidrológicos, justificado pela dificuldade na obtenção desses dados. Este projeto propôs o desenvolvimento de um equipamento que permite realizar medidas em campo da interceptação da serrapilheira em área de cerrado sensu stricto. Com o equipamento desenvolvido, LID (Litter Interception Device), são realizadas medidas do volume de água retido na serrapilheira e do volume que passa pela serrapilheira, atingindo o solo. O LID foi testado e calibrado em laboratório utilizando chuva simulada de três diferentes intensidades sobre o equipamento, contendo três quantidades diferentes de serrapilheira, 2,97, 1,45 e 0,60 kg.m-2. As amostras de serrapilheira utilizadas nos testes foram retiradas de uma área experimental de mata nativa de cerrado sensu stricto, localizada no município de Itirapina, Estado de São Paulo. As intensidades utilizadas foram definidas a partir de uma curva Intensidade-Duração-Frequência (IDF) gerada para a área experimental. Além do bom funcionamento do LID, os testes serviram para determinar os parâmetros Cmax e Cmin (capacidade máxima e capacidade mínima de armazenamento, respectivamente) da serrapilheira do cerrado sensu stricto. Os resultados mostraram que com o LID são realizadas medições da taxa de retenção de água na serrapilheira (mm.min-1), bem como de sua evaporação (mm.min-1) com precisão. Os testes para calibração do pluviógrafo revelaram que as medidas eram sempre subestimadas, necessitando utilizar uma curva de calibração (R2 = 0,99) para corrigir os registros da intensidade que passa para o pluviógrafo. Os valores encontrados para os parâmetros Cmax (1,0 a 3,07 mm) e Cmin (0,78 a 2,27 mm) corroboram com os encontrados por outros autores para a serrapilheira de diferentes florestas. Verificou-se que a variável quantidade de serrapilheira (kg) influencia mais nesses valores, do que a intensidade da chuva (mm.h-1). Conclui-se com os resultados que o LID pode ser utilizado em estudos que pretendam analisar o papel da serrapilheira em processos hidrológicos, sejam estes para a determinação da interceptação da chuva em campo, ou mesmo na determinação de parâmetros em laboratório. / Forest litter is the layer above the ground of the forest formed by materials that fall from the vegetation itself. The vegetation materials are through various stages of decomposition, functioning as a mechanism of rainfall interception. Although the interception process is significant in forested areas, this process is usually underestimated or even neglected in hydrological models due to the difficulties on obtaining these data. We proposed the development of a device that allows the field measurements of the forest litter interception in a cerrado sensu stricto area. The Litter Interception Device (LID), was tested and calibrated in the laboratory. We used simulated rainfall with three different intensities to test the device and also three different amounts of litter, 0.100, 0.230 and 0.470 kg. The litter samples used in the tests were taken from an experimental area of cerrado sensu stricto located in Itirapina, State of São Paulo, Brazil. The intensities of simulated rainfall were obtained from an Intensity-Duration-Frequency (IDF) curve made for the experimental area. Besides the LID functioning tests, the device was tested to determine the parameters Cmax and Cmin (maximum capacity and minimum storage capacity, respectively) of the cerrado sensu stricto forest litter. The results showed that the LID allows measurements of the volume of water retained in the forest litter (mm.min-1) as well as its evaporation (mm.min-1). The pluviometer calibration tests revealed that the measurements were always underestimated, requiring a calibration curve (R2 = 0.99) to correct the volume records that flow to the tipping bucket pluviometer. The values found for Cmax (1.0 - 3.07 mm) and Cmin (0.78 - 2.27 mm) are according with those found by other authors for different kinds of forest litters. It was verified that the variation in the amount of forest litter (kg) influenced more in these values, than the rainfall intensity (mm.min-1) . We concluded that the LID can be used in studies that intend to analyze the role of the forest litter in hydrological processes, whether they area for the determination of the interception of rain in the field or even and in laboratory studies to determine interception parameters of forest litter.
20

Pd/Al<sub>2</sub>O<sub>3</sub> -based automotive exhaust gas catalysts:the effect of BaO and OSC material on NO<sub>x</sub> reduction

Kolli, T. (Tanja) 02 May 2006 (has links)
Abstract The aim of the thesis was to find new information on the effect of BaO and oxygen storage capacity material on NOx reduction. A total of nine different kinds of Pd/Al2O3-based metallic monoliths were studied. Promoters such as oxygen storage capacity material (OSC material in our case Cex-1ZrxO2 mixed oxides) and stabilisers such as barium (BaO) were added into the catalyst alone or together to improve catalyst properties such as catalytic activity, selectivity, and thermal stability. The key aspects in this thesis can be divided into four parts. First, the behaviour of NO reduction and CO as well as C2H4 oxidation over Pd/Al2O3-based catalysts in rich, stoichiometric and lean conditions were studied. Secondly, the effect of BaO and the OSC material in NO reduction was considered. Thirdly, the preparation procedure, i.e. the addition order of BaO, OSC material, and Pd on the catalyst was considered. Finally, the effect of ageing on the behaviour of catalysts was investigated. Several characterization methods (in situ DRIFT, catalytic activity measurements, N2 physisorption, CO chemisorption, dynamic oxygen storage capacity measurements, and X-ray diffraction (XRD)) were utilised to find answers to the behaviour of these catalysts in the studied model reactions. The Rapid Ageing Hot in Laboratory (RAHLAB) method was used to age the catalyst. First, it was demonstrated that the CO and hydrocarbon oxidation and NO reduction reactions over the Pd/Al2O3-based catalyst behave differently. NO reduction and CO and hydrocarbon oxidation reactions were dependent on the reaction conditions and temperatures. Secondly, the effect of OSC and BaO on NO reduction was studied separately. In the case of OSC material, it was observed that the OSC material has an effect on NO reduction as well as on CO and C2H4 oxidation. In the case of BaO, it was observed that BaO has a positive effect on NO reduction as well as CO and C2H4 oxidation especially in rich conditions. Thirdly, the effects of the addition order of OSC and BaO on the catalyst was studied separately. It was shown that these have an effect on NO reduction, especially after ageing. First, on the fresh Pd/Al2O3 catalyst it was observed that the addition order of OSC on the catalyst has not an influence on catalyst performance. The effect of the BaO addition order on the Pd/OSC/Al2O3-based catalyst is found to be insignificant, especially, after the ageing process. Furthermore, it is observed that the effect of RAHLAB ageing was that the catalyst lost its catalytic activity, stability, and selectivity.

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