• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • 1
  • Tagged with
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 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.
1

Dispersão geoquímica elementar e isotópica na atmosfera e no solo em área com atividade minerária e termoelétrica a carvão / Geochemical dispersion of elements and radionuclides in the atmosphere and soil of an area with mining and coal-fired thermoelectric power plant activities

Campaner, Veridiana Polvani 1981- 22 August 2018 (has links)
Orientador: Wanilson Luiz Silva / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Geociências / Made available in DSpace on 2018-08-22T21:27:48Z (GMT). No. of bitstreams: 1 Campaner_VeridianaPolvani1981-_D.pdf: 3461719 bytes, checksum: 9a5bc42ac7776e7105fbf8108a902f11 (MD5) Previous issue date: 2013 / Resumo: A identificação de anomalias antrópicas de elementos no solo e na atmosfera necessita do discernimento de possíveis mistura e dispersão de fontes antrópica e natural. Em área com atividade minerária e termoelétrica a carvão, no município de Figueira (PR), foram investigadas a distribuição multielementar (e.g. As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Sb, U, Zn e radionuclídeos) em carvão, cinzas, rochas, solo e no material particulado atmosférico (partículas fina e grossa). Nos perfis de solo e no solo de superfície, a influência do carvão e cinzas resultou em assinaturas geoquímicas As/Zr, Cd/Zr, Hg/Zr, Mo/Zr, Pb/Zr, Sb/Zr, U/Zr e Zn/Zr elevadas, devido à mistura destas razões de origem natural no solo com àquelas do carvão e das cinzas. Os diques de diabásio regionais apresentaram assinaturas geoquímicas Co/Zr, Cr/Zr, Cu/Zr, Ni/Zr e Sc/Zr na configuração da paisagem pedológica da área de estudo, onde a maior influência foi de rochas sedimentares. A intensidade das anomalias antrópicas no solo de superfície foi maior para As, Cd e Mo, seguidos por Hg, Zn, Pb, Sb e U (ordem decrescente de intensidade). Estas anomalias mostraram uma distribuição espacial no solo de superfície condizente com a direção predominante dos ventos na área, e sugerem que eventos de deposição atmosférica por longo período devem ter sido a principal fonte destes elementos no solo. No material particulado atmosférico, observou-se o enriquecimento dos mesmos elementos associados ao carvão e às cinzas. Entretanto, uma mistura de fontes natural (considerada por meio da avaliação das amostras de solo da base dos perfis) e antrópica (carvão e cinzas) foram reveladas por assinaturas geoquímicas As/Mo. O carvão e as cinzas de Figueira (PR) apresentaram assinaturas As/Mo iguais a 15,2 ± 4,25 e 15,9 ± 2,42, respectivamente. Estas assinaturas foram diferentes daquela encontrada no solo (As/Mo = 8,49 ± 3,13) e levemente contrastantes com a razão As/Mo dos materiais particulados atmosféricos finos e grossos (média igual a 11,4). Como resultado, o modelo As/Mo da área de estudo quantificou a contribuição do carvão e das cinzas em 41% e do solo em 59% na atmosfera. O carvão e as cinzas de Figueira (PR) apresentaram elevadas concentrações de 238U, 226Ra e 210Pb, especialmente. Dentre estes radionuclídeos, o 210Pb destacou-se por apresentar maior distribuição espacial no solo em função de suas atividades e condições de desequilíbrio com o 226Ra (210Pb/226Ra), avaliadas tanto nos perfis de solo quanto no solo de superfície. No material particulado atmosférico, as condições de desequilíbrio 210Pb/226Ra foram mais intensas nas proximidades da usina termoelétrica. Isso indica que o 210Pb deve ter tido uma fonte adicional na atmosfera por meio da emanação do gás 222Rn proveniente, particularmente, da queima do carvão na termoelétrica. Neste estudo a investigação holística de elementos químicos e radionuclídeos em área com atividade minerária contribuiu para uma avaliação mais consistente da influência antrópica no solo e na atmosfera / Abstract: The identification of elemental anomalies in soil and atmosphere caused by human activities is necessarily preceded by the identification of possible mixtures and dispersion of anthropic and natural sources. An area affected by mining and coal-fired thermoelectric power plant activities in the Figueira municipality (Paraná, Brazil) was investigated for multi-elemental distribution (e.g. As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Sb, U, Zn, and radionuclides) in coal, ashes, rocks, soil, and in the atmospheric (fine- and coarse-grained) particulate material. In soil profiles and in the superficial soil, the influence of coal and ashes resulted in high As/Zr, Cd/Zr, Hg/Zr, Mo/Zr, Pb/Zr, Sb/Zr, U/Zr, and Zn/Zr geochemical signatures, due to the mixture of natural ratios of such elements found in soil with the ratios found in coal and ashes. As for natural ratios, the diabase dikes contributed with Co/Zr, Cr/Zr, Cu/Zr, Ni/Zr, and Sc/Zr geochemical signatures to the configuration of the pedological landscape of the study area, where the major influence comes from sedimentary rocks. The anthropic anomalies in superficial soil were, in descending order, higher for As, Cd, and Mo, followed by Hg, Zn, Pb, Sb, and U. The spatial distribution of these anomalies in the superficial soil were consistent with the predominant wind directions and suggests that long-term atmospheric deposition must have been the main source for these elements in the soil. The atmospheric particulate material is enriched in the elements associated with coal and ashes in soil. However, a mixture of natural sources (assessed by means of soil samples from the base of the soil sections) and anthropic sources (coal and ashes) was revealed by As/Mo ratios. The coal and ashes from Figueira yielded, respectively, As/Mo signatures of 15.2 ± 4.25 and 15.9 ± 2.42. These signatures differ from that obtained for soil (As/Mo = 8.49 ± 3.13), and slightly differ from the As/Mo value obtained for atmospheric particulate material (average As/Mo = 11.4). As a result, the As/Mo model for the study area helped quantify the contributions from coal and ashes (41%) and soil (59%) to the atmosphere. Coal and ashes from Figueira have high 238U, 226Ra, and 210Pb activities. The largest spatial distribution in soil corresponds to 210Pb, because of its chemical activities and disequilibrium with 226Ra (210Pb/226Ra), observed both in the soil profiles and in the superficial soil. In the atmospheric particulate material, the 210Pb/226Ra disequilibrium is more intense close to the coal-fired thermoelectric power plant. This indicates that an additional source for 210Pb in the atmosphere was the emanation of gas 222Rn resulting from the burning of coal in the plant. The holistic investigation carried out in this study involving chemical elements and radionuclides in an area affected by mining activities contributed for a more consistent evaluation of the anthropic influence in soil and atmosphere / Doutorado / Geologia e Recursos Naturais / Doutora em Ciências
2

Modeliranje turbulentnog transporta ugljen-dioksida i azotnih oksida u površinskom sloju atmosfere iznad ruralne oblasti / Modeling of turbulent transport of carbon dioxide and nitrogen oxides in the atmosphere surface layer above the rural areas

Firanj Ana 13 March 2015 (has links)
<p>U okviru doktorske disertacije predstavljeni su postojeći i novi koncepti modeliranja<br />turbulentnog transporta ugljen-dioksida i azotnih oksida u povr&scaron;inskom sloju atmosfere<br />iznad ruralne oblasti. Cilj istraživanja je da se na osnovu postojećih saznanja o procesima<br />koji opisuju interakciju tlo-vegetacija-atmosfera i rezultata mikrometeorolo&scaron;kih<br />eksperimenata unapredi modeliranje procesa interakcije. Poseban akcenat stavljen je na<br />modeliranje turbulentnog transporta gasova iznad i unutar &scaron;umskog sklopa. Uticaj<br />vertikalne heterogenosti biljnog sklopa uveden je u predloženi postupak skaliranja<br />asimilacije ugljen-dioksida sa lista na biljni sklop i suve depozicije azotnih oksida.<br />Predloženi koncepti testirani su u okviru fizičke LAPS i hemijske MLC-Chem povr&scaron;inske<br />sheme. Za potrebe modeliranja turbulentnog transporta ugljen-dioksida razvijen je<br />modul za parametrizaciju intenziteta fotosinteze. Kvantitativna analiza rezultata izvedena<br />je poređenjem osmotrenih i simuliranih vrednosti turbulentnih flukseva ugljen-dioksida i<br />azotnih oksida na četiri karakteristična &scaron;umska sklopa. Unapređenje modeliranja<br />izvedeno je kaplovanjem testiranih povr&scaron;inskih shema u MLC-LAPS shemu. Kvalitet<br />simulacija MLC-LAPS sheme proveren je poređenjem izlaznih i osmotrenih<br />mikrometeorolo&scaron;kih veličina, koncentracije i turbulentnih flukseva gasova.</p> / <p>This PhD thesis deals with the current and new concepts of modeling turbulent<br />transport of carbon dioxide and nitrogen oxides in the surface layer of the atmosphere<br />above the rural areas. The aim of this research is to improve modeling of the interaction<br />between soil-vegetation-atmosphere based on existing knowledge about the processes<br />describing the interaction and results of micrometeorological experiments. Special<br />emphasis is placed on the modeling of turbulent transport of gases above and within<br />the forest canopy. Influence of vertical canopy heterogeneity was introduced in the<br />proposed method for scaling the assimilation of carbon dioxide from the leaf to canopy level and dry deposition of nitrogen oxides. The presented concepts are tested within the physical LAPS and chemical MLC-Chem surface schemes. For the purposes of modeling the turbulent transport of carbon dioxide the module for parameterization of photosynthesis was developed. Quantitative analysis of the results were made by comparing the observed and simulated values of turbulent fluxes of carbon dioxide and nitrogen oxides in four distinctive forest canopies. Modeling improvement was performed by coupling tested surface schemes into MLC-LAPS scheme. Quality of MLCLAPS scheme simulations is verified by comparing the output and observed micrometeorological elements and turbulent fluxes of energy and gases.</p>

Page generated in 0.0287 seconds