Made available in DSpace on 2017-07-21T19:25:49Z (GMT). No. of bitstreams: 1 Jaqueline Ap Borges.pdf: 4346896 bytes, checksum: 7cddb136f61196f7c1bd6d777eaee0bc (MD5) Previous issue date: 2015-09-11 / In this study, the Computed Tomography (CT) and gamma-ray attenuation (GRA) techniques were used in the investigation of representative sample sizes for attributes related to soil structure. First of all, the representative elementary length (REL) for experimental measurements of soil mass attenuation coefficient (μes), of samples from a sandy and a clayey soil, was analyzed. The study was conducted with two radioactive sources (241Am and 137Cs), three collimators (2–4 mm diameters), and 14 thickness (x) samples (2–15 cm). From these analyzes, it was possible to identify an ideal thickness range for each of the studied sources (2-4 cm and 12-15 cm for the sources of 241Am and 137Cs, respectively). The application of such results in representative elementary area evaluations, in clayey soil clods via CT, indicated that experimental soil mass attenuation coefficient average values obtained for x>4 cm and source 241Am might induce the use of samples which are not large enough for soil bulk density evaluations. Subsequently, μCT images with a total volume of 39×39×33 mm3 and spatial resolution of 60 μm were used for macroporous system morphological characterization of a Rhodic Ferralsol with clayey texture, under no-till (NT) and conventional till (CT) systems. Attributes as macroporosity (MAP), number of macropores (NMAP), tortuosity (τ) and connectivity (C) of the pores were assessed. The C degree was estimated based on the Euler-Poincaré characteristic (EPC). Once 3D images enable the study of these attributes in different sample volumes, the proposed study is ideal for the analysis of representative elementary volume (REV). Usually, the selection of subvolumes for REV analysis occurs concentrically to a small volume or in adjacent positions. Here, we introduced a new method for selecting the positions of subvolumes, which are randomly chosen within the total image volume (random selection). It was observed that higher fluctuations in amplitude of each analyzed property values occurred for smaller subvolumes and random selection. When these positions are randomly selected, all regions of the sample have the same probability of occurrence. Thus, the subvolumes can be selected from regions that exhibit similar characteristics, or which are quite different from each other. The results allowed the study of each of these attributes in function of the analyzed sample volume. Such analysis enabled the identification of a REV for MAP and τ measurements for both soils. However, NMAP and CEP showed no indication of stabilization within the total sample volume analyzed (39×39×33 mm3). From this study, it was possible to detect the influence of each management systems (NT and CT) on the macroporous system. In general, results obtained for soil under PC showed higher regularity, which is probably due to its homogenization induced by the plowing, conducted twice a year. / No presente estudo, as técnicas de tomografia computadorizada (TC) e atenuação de raios gama (AGR) foram utilizadas na investigação do tamanho representativo de amostras para atributos referentes à estrutura do solo. Primeiramente, foi analisado o comprimento elementar representativo (CER) de amostras de um solo de textura arenosa e outro de textura argilosa para medidas experimentais do coeficiente de atenuação de massa do solo (μes). O estudo foi realizado com duas fontes radioativas de raios gama (241Am e 137Cs), três aberturas de colimadores circulares (2-4 mm) e 14 espessuras (x) distintas de amostras deformadas de solo (2-15 cm). A partir destas análises foi possível identificar um intervalo de espessura ideal para cada uma das fontes estudadas (2–4 cm e 12–15 cm para as fontes de 241Am e 137Cs, respectivamente). A aplicação dos resultados obtidos para a fonte de 241Am, e solo argiloso, em avaliações de área elementar representativa (AER) para medidas de densidade do solo (ρs) via TC, indicaram que os valores médios de μes para x>4 cm podem induzir ao uso de amostras com tamanho não representativo. Na sequência, imagens de microtomografia de raios X (μTC), com volume total de 39×39×33 mm3 e resolução espacial de 60 μm, foram utilizadas para a caracterização micromorfológica do sistema macroporoso de um Latossolo vermelho de textura argilosa, submetido aos sistemas de manejo de plantio direto (PD) e plantio convencional (PC). Foram analisados atributos físicos como macroporosidade (MAP), número de macroporos (NMAP), tortuosidade (τ) e conectividade (C) dos poros. O grau de C dos poros foi estimado a partir da característica de Euler-Poincaré (CEP). Uma vez que imagens 3D possibilitam o estudo destes atributos em diferentes volumes de amostra, o estudo proposto é ideal para a análise de volumes elementares representativos (VERs). Geralmente, a seleção dos subvolumes para análises de VER se dá concentricamente a um volume de origem ou em posições adjacentes a este. Neste trabalho foi introduzida uma nova forma de seleção da posição dos subvolumes, os quais são selecionados randomicamente dentro do volume total da imagem (seleção aleatória). Observou-se que as maiores amplitudes de flutuações nos valores de cada atributo analisado ocorreram para os subvolumes menores quando selecionados de forma aleatória, em comparação à seleção centralizada. Quando estas posições são selecionadas aleatoriamente, todas as regiões da amostra têm a mesma probabilidade de ocorrência. Com isso, os subvolumes podem ser selecionados em regiões que apresentem características similares, ou então, que sejam muito diferentes umas das outras. Os resultados permitiram o estudo de cada um destes atributos em função do volume de amostra analisado. Tais análises possibilitaram a identificação de um VER para medidas de MAP e τ para os dois solos estudados. No entanto, a NMAP e a CEP não apresentaram indícios de estabilização até o volume total de amostra analisado (39×39×33 mm3). Quanto aos dois sistemas de manejo avaliados (PD e PC), foi possível detectar a influência de cada um deles na estrutura macroporosa do solo. De uma forma geral, o solo sob PC apresentou maior regularidade nos resultados obtidos, o que se deve à homogeneização do mesmo induzida pelo revolvimento do solo realizado duas vezes ao ano.

In the last three decades, seismic performance assessment of buried structures has evolved through the following stages : i) buried structures are not prone to seismically-induced damages, thus no need for detailed investigations, ii) eliminating soil-structure-earthquake interaction and use of seismically-induced free field ground deformations directly as the basis for seismic demand, thus producing conservative results, and finally iii) soil-structure and earthquake interaction models incorporating both kinematic and inertial interactions. As part of soil-structure and earthquake interacting models, simplified frame analysis established the state of practice and is widely used. Within the confines of this thesis, the results of simplified frame analysis based response of buried structures are compared with those of 2-D finite element dynamic analyses. For the purpose, 1-D dynamic and 2-D pseudo-dynamic analyses of free field and buried structural systems are performed for a number of generic soil, structure and earthquake combinations. The analyses results revealed that, in general, available closed form solutions are in pretty good agreement with the results of finite element analyses. However, due to the fact that dynamic analyses can model both kinematic and inertial effects / it should be preffered for the design of critical structures.

The consequence of the differentiation of a care of forest ecosystems in NP Šumava is the existence of localities where timber harvesting causes damage to forest ecosystem. One of the most affected ecosystems is the soil ecosystem. The surface is usually disrupted by numbers of passing over the same path the machines. Forwarders are the harvesting machineries that execute the largest number of passes in the forest. The aim of the diploma work is to gain and analyse data dealing with harvesting technologies, and to evaluate their impact on soil ecosystems. The impact was determinate from measuring of the recessing of the track in the surface, of the soil compaction and of the soil sampling for determination of an amount of the water in the soil. The data were measured in different selected localities in NP Šumava. The negative influences of the harvesting technologies were defined for both {--} water and air regime of soil. Recommendation for reduction of negative consequences of the harvesting on soil are parts of diploma work as well.

Wetlands serve important ecosystem functions such as carbon sequestration but are often affected by disturbances like urban development, agriculture, and road building. For wetlands created to mitigate losses, it is important that the ecosystem functions successfully replicate those of natural wetlands. Created wetlands have frequently not provided these functions due to issues including low organic carbon (OC), high soil bulk density (BD), lost topsoil, incorrect hydrology, and failure of targeted vegetation establishment. Organic matter (OM) amendments help created wetlands attain these functions quicker, but, their long-term effects are seldom reported. This research's purpose was to measure the long-term effects of treatments at a sandy tidal freshwater wetland created in 2003 (WWE) and a fine-textured, non-tidal wetland created in 2002 (CCW). We tested OM treatments, topsoil amendment, and microtopography effects on soil and vegetation properties at WWE and OM treatments at CCW. Pedogenic changes in soil morphology, physical and chemical properties were detected by comparing data to previous studies at these sites. At both sites, litter and biomass parameters were measured to estimate total mass C. Herbaceous biomass was measured at WWE. At WWE, no long-term OM treatment effects from 78 or 156 Mg ha-1 were observed. Soils in pits had higher OC, lower BD, and lower chroma than soils on mounds. Sandy and loamy HSFI's developed at WWE within four years, but there were fewer sandy indicators after 12 years. Loamy HSFI's were lost at CCW from 2003 to 2016. Plots at WWE that were amended with topsoil had higher soil mass C than the sandy soil due to a finer texture, but total mass C did not vary. At CCW, long-term OM treatment effects were observed, including lower BD, higher soil mass C, and higher tree mass C with increasing compost rates up to 224 Mg ha-1. Overall, the ideal compost loading rate for constructed wetlands varied with wetland type and mitigation goals. Compost rates of 112 Mg ha-1 are sufficient for short term establishment of wetland vegetation and hydric soil properties, but higher rates near 224 Mg ha-1 may be required for effects that last over 10 years. / Ph. D.

Submitted by Angela Maria de Oliveira (amolivei@uepg.br) on 2018-06-06T14:39:52Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Tech, Lohane.pdf: 2007649 bytes, checksum: ed3cf3b82a08ab6680c21d8be8071469 (MD5) / Made available in DSpace on 2018-06-06T14:39:52Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Tech, Lohane.pdf: 2007649 bytes, checksum: ed3cf3b82a08ab6680c21d8be8071469 (MD5) Previous issue date: 2018-02-26 / No presente trabalho foram analisadas 25 solos com diversas texturas, do estado do Paraná Brasil. Com o intuito de avaliar os parâmetros de interação da radiação com os solos, as amostras foram submetidas a análise semi-quantitativa por fluorescência de raios X (FRX) por dispersão de energia a fim de se obter os teores dos óxidos que compunham o solo. Dois tamanhos de partículas foram analisados, sendo eles: diâmetro de 45 μm, que é o padrão recomendado pelo fabricante do equipamento de FRX, e diâmetro de 2-1 mm. O teor dos óxidos, o coeficiente de atenuação de massa (⁄), a seção de choque molecular (), a seção de choque atômica (), a seção de choque eletrônica (), o número atômico efetivo () e a densidade eletrônica (), foram analisadas para os 25 solos para os dois tamanhos de partículas. Os resultados mostraram diferenças nos teores de óxidos dos solos entre um tamanho de agregado e outro, constatando mudanças nas porcentagens do óxidos de Al2O3, SiO2 e Fe2O3. Como consequência, houve alteração nos valores dos outros parâmetros analisados, as seções de choque, o número atômico efetivo e a densidade eletrônica. A seção de choque molecular e a densidade eletrônica mostrou dependência com o teor dos óxidos Al2O3 e SiO2, que são encontrados em maior porcentagem nos solos arenosos e nos solos com textura franco, para os dois tamanhos de agregados. A seção de choque atômica mostrou dependência com o número total de unidades de fórmulas moleculares presentes na composição do solo. Já os parâmetros restantes, coeficiente de atenuação de massa, seção de choque eletrônica e número atômico efetivo mostraram dependência com o óxido Fe2O3, que é encontrado em maior teor nas amostras com textura mais argilosa, para os dois tamanhos de agregados. Desta forma, observou-se dependência da textura e do tamanho de partículas ambas com a composição química elementar porque no primeiro caso, diferentes texturas são relacionadas a composição mineral e elementar nos diferentes solos e a segunda devido a conformação dos agregados nos dois conjuntos analisados. / This study analysed 25 soil samples from the State of Paraná, Brazil, with different textures. Aiming at evaluating the parameters of radiation interaction with the matter, the samples were submitted to the semi-quantitative analysis using energy dispersive X-ray (XRF) fluorescence, to obtain the content of oxides contained in the soil mixture. Two particle sizes were analysed, being: the 45 μm, wich is the standard required by the manufacturer of the X-ray fluorescence equipment, and the 2-1mm. The oxide content, mass attenuation coefficient (⁄), molecular cross section (), atomic cross section (), electronic cross section (), effective atomic number () and the electronic density () were analysed in the 25 samples and for the two particle sizes. The results showed differences in the soil oxide content between one aggregate size and the other, revealing changes in the percentage of the Al2O3, SiO2 and Fe2O3 oxides. With the difference observed, there was change in the values of other parameters under analysis, the cross sections, the effective atomic number and the electronic density. The molecular cross section and the effective electronic density showed dependence on the content of Al2O3 and SiO2 oxides, which were found in higher percentages in sandy and loam soils, for both aggregate sizes. The atomic cross section was seen to present dependence on the total number of molecular formula units contained in the soil composition. While the remaining parameters, mass attenuation coefficient, electronic cross sections and the effective atomic number showed dependence on the Fe2O3 oxide, whose higher contents were found in the clay textured samples, for both aggregate sizes. In this way, it was observed texture and size dependency, both with the elementary chemical composition because in the first case, different textures are related to elementary and mineral composition in the different soils and the second due to the conformation of the aggregated in both analyzed arrays.