Resumo: A falta de detalhamento nas informações sobre os atributos do solo, nas áreas cultivadas é um fator limitante para aumentar a assertividade na alocação de variedades de cana-de-açúcar em diversos ambientes edafoclimáticos. Atualmente, o conceito de ambientes de produção é amplamente utilizado para classificar o potencial de produtividade dos solos, e a suscetibilidade magnética surge como uma ferramenta importante para mapear áreas de forma ultradetalhada e com baixo custo. Nesse contexto, este trabalho tem como objetivo avaliar a utilização da suscetibilidade magnética como ferramenta na identificação de áreas com diferentes potenciais para produtividade e qualidade de cana-de-açúcar e sua utilização na alocação de variedades. Foram amostrados 445 ha com grid de 1 ponto a cada 5 hectares e, seguindo o espigão da paisagem, foram determinados 14 pontos para amostragem estratificada. Analisaram-se a granulometria e a suscetibilidade magnética de amostras, nas profundidades de 0,0-0,2 m e 0,2-0,4 m. Os dados de produtividade e de qualidade da matéria-prima foram obtidos via banco de dados de 9 safras e biometria realizada na safra de 2018/2019. Como resultados, observou-se alta correlação dos teores de argila e de areia com a expressão magnética. Pela análise multivariada dos resultados históricos, observou-se a organização de 3 grupos com diferentes potenciais de produtividade e de qualidade, diferenciando em até 17,28TCH o resultado entre o grupo com maior e menor potencial, b... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The lack of detail in the information on soil attributes in cultivated areas is a limiting factor to increase assertiveness in the allocation of sugarcane varieties in various edaphoclimatic environments. Nowadays, the concept of production environments is used to classify soil execution potential and a magnetic increase in susceptibility as an important tool for mapping ultra-detailed and low cost areas. In this context, this work aims to evaluate magnetic susceptibility, how to use tools to identify areas with different levels of use and quality of sugarcane and its use in the allocation of varieties. 445 ha were sampled with 1 point grid every 5 hectares and, following the understanding of the landscape, 14 points were selected for stratified sampling. Particle size and magnetic susceptibility of dimensions at depths of 0.0-0.2 m and 0.2-0.4 m were analyzed. Test data and raw material quality data were obtained through a 9-crop database and biometrics performed in the 2018/2019 crop. As a result, high correlation of clay and sand content with magnetic expression. By multivariate analysis of historical results, it is possible to organize 3 groups with different levels of use and quality, differentiating up to 17.28TCH or the result between the group with higher and lower potential, based on soil magnetic susceptibility. For biometrics results, as the classes of higher magnetic susceptibility observed in the largest difference and lowest sugar accumulation. Analyzing variety... (Complete abstract click electronic access below) / Mestre

Cette étude est dédiée à la période charnière que constituent lEifélien et la base du Givétien en Belgique et les régions limitrophes, entre le Dévonien inférieur caractérisé par des dépôts détritiques et linstallation dune plate-forme carbonatée au Givétien. Létude sédimentologique détaillée que nous avons entreprise est le résultat de lintégration de différentes techniques danalyses : sur le terrain (levé et description banc par banc), en lame mince (pétrographie et microfaciès) et sur les échantillons (susceptibilité magnétique et analyses chimiques). Dans le cadre de ce travail, ce sont 14 coupes qui ont été levées, représentant une épaisseur totale de 1650 mètres. Les études de terrain ont permis de mettre en évidence une grande variété de faciès carbonatés, détritiques ou mixtes. Cette variété illustre parfaitement la variabilité latérale qui est la règle au sein de ces niveaux. Les analyses pétrographiques qui ont été menées sur 3352 lames minces, confirment cette diversité et aboutissent à la définition de 71 microfaciès. Ces microfaciès sont répartis sur un modèle de plate-forme et sur 6 modèles de rampe. Ces différents modèles de rampe se distinguent les uns des autres par une influence terrigène plus ou moins marquée, le développement ou non de bioconstructions ou encore la présence ou non de shoals. Les analyses de susceptibilité magnétique on permis de mettre en évidence trois paramètres sédimentologiques principaux linfluençant : lapport détritique (le continent étant la source principale des minéraux porteurs du signal), lagitation (qui peut empêcher le dépôt de ces mêmes minéraux) et la productivité carbonatée (qui peut diluer ces minéraux). Les analyses chimiques quant à elles permettent de clairement dégager 4 pôles parmi les minéraux présents dans les échantillons, chacun ayant sa contribution propre à la valeur de susceptibilité magnétique. Le premier est le contenu en carbonates qui est directement lié à la productivité carbonatée. Outre le quartz détritique, lapport terrigène comporte de son côté deux pôles distincts : lun sous forme dargiles et lautre sous forme de minéraux ferromagnétiques primaires. Le dernier pôle correspond à linfluence de la diagenèse par la dolomitisation et la cristallisation de pyrite, dhématite et éventuellement de magnétite. De par la répartition générale des trois paramètres sédimentologiques cités ci-dessus sur les profils de plate-forme et de rampes, trois types dévolution des courbes de susceptibilité magnétique se dessinent quand on la compare à lévolution des microfaciès. Certaines coupes ne montrent aucun lien entre les deux types de courbes, la susceptibilité magnétique restant relativement constante. Ensuite, un parallélisme peut sobserver entre les deux types de courbes (à une baisse de niveau marin, correspond une hausse de valeurs de susceptibilité magnétique et inversement). Enfin, une opposition peut être observée entre les deux types de courbes (à une baisse de niveau marin, correspond une baisse de valeurs de susceptibilité magnétique et inversement). Une fois identifiés, ces comportements relativement cohérents permettent lutilisation de la susceptibilité magnétique à des fins de corrélation. Lintégration de lensemble des données et interprétations aboutit à la proposition dun canevas de stratigraphie séquentielle. La généralisation de ce canevas à lensemble du bord Sud du Synclinorium de Dinant permet une meilleure compréhension du passage latéral entre la Formation de Couvin et la Formation de Jemelle et de linstallation de la plate-forme carbonatée à la transition Eifélien-Givétien.

The Stone Age settlement site outside the village of Vuollerim in northern Sweden was first discovered in the 1980s and has been an important part of the research regarding Mesolithic and Neolithic in Norrland. One of the houses on the site was named Norpan 2 and nearly fifteen hundred soil samples were collected and stored during the excavations between 1983 and 1987. This study has focused on analysing nearly one thousand of the collected soil samples using phosphate and magnetic susceptibility analysis to further study activity on site and social structure. Furthermore, due to the large quantity of samples, a short comparison of soil sampling density was made to perceive the effect sampling density has on the interpretation of soil mapping. The results of the study indicate that the site has a large deposit of Magnetite (Fe3O4) in the soil that gives unusual MS-readings from the collected samples. The results also show a bipolar separation of finds and geoarchaeological traces within the house. This distinctive separation has been argued as an indication of dividing the space between families, but this study indicate that this separation might be due to house being divided between different activities but the evidence is not conclusive enough without further studies. The study has also shown that while a high density soil mapping gives much greater details it is still possible to gain the necessary information with fewer samples. In conclusion, it is still too early to conclude the investigations at the Vuollerim site and with the added data from this study and new information there is still more to learn from the Vuollerim site.KeywordsPhosphate analysis, Magnetic susceptibility, Vuollerim, Norpan 2, Geoarchaeology, Soil mapping

Articial spin ice structures are two-dimensional systems of lithographically fabricated lattices ofelongated ferromagnetic islands, which interact via dipolar interaction. These systems have beenshown to be a suitable playground to study the magnetic, monopole-like, excitations, similar tothose in three-dimensional rare-earth pyrochlores. Therefore, such articial structures can be potentialmaterials for investigations of magnetricity [1]. The investigations of these articial spin icestructures stretches from the direct imaging of the magnetic congurations among the islands to indirectinvestigation methods allowing to determine the phase transitions occurring in such systems. Inthis project, square articial spin ice arrays were investigated employing magneto-optical Kerr eectfor the measurement of the magnetic susceptibility. The susceptibility dependence on temperaturewas measured at dierent frequencies of the applied AC magnetic eld for arrays of the dierentisland spacing and at two dierent incident light directions with the respect to the direction of theislands. A peak shift of the real part of susceptibility, χ', with increasing frequency towards thehigher temperatures was observed. Furthermore, a rough estimation of the relaxation times of themagnetic moments in the islands is given by the analysis of the susceptibility data.

Carbonatites are carbonate-rich magmatic rocks that are rare and of great relevance for our understanding of crustal and mantle processes. Although found on all continents and in settings ranging from Archaean to present-day, their deeper plumbing system is still poorly understood. Therefore, the main goal of this thesis is to broaden the existing knowledge of carbonatite systems, often limited to surface geological observations, by providing depth constraints using a number of geophysical methods and petrophysical measurements. The Alnö alkaline and carbonatite complex in central Sweden was chosen for this purpose. Data from three reflection seismic lines, ground gravity and magnetic measurements are presented. These data are complemented by a series of petrophysical measurements, including ultrasonic velocities, density, magnetic bulk susceptibility, anisotropy of magnetic susceptibility (AMS), and magnetic remanence, to aid in the interpretation of the geophysical data. The reflection seismic data indicate a solidified saucer-shaped fossil magma chamber at about 3 km depth. Caldera-style volcanism, constrained by surface geological observations, provides a plausible scenario to explain the emplacement of the complex, suggesting that carbonatite magmas have been stored, transported and erupted in a similar manner to known emplacement mechanisms for silicic calderas, although these are compositionally different. The AMS data from most of the carbonatite sheets in Alnö show a strong degree of anisotropy and oblate-shaped susceptibility ellipsoids. A set of syn- and post-emplacement processes that may control the AMS signature is evaluated based on the dataset. Overprinting of the primary flow patterns by processes related to sheet closure at the terminal stage of magma transport may explain the AMS observations. A complementary study using 3D inversion of ground gravity and aeromagnetic data was then carried out to better delineate the 3D internal architecture of the complex. Resulting models indicate a depth extent of the complex to about 3-4 km, consistent with the interpretation of the reflection seismic data. The modelling results of a ring-shaped magnetic anomaly observed in the Klingefjärden bay adjacent to Alnö Island further suggest that the complex may extend laterally about 3 km towards the north.

Thesis (Ph. D.)--Florida State University, 2004. / Advisors: Dr. Naresh Dalal, Dr. Johan van Tol, Florida State University, Arts and Sciences, Dept. of Chemistry and Biochemistry. Title and description from dissertation home page (viewed Jan. 18, 2005). Includes bibliographical references.

Thesis (M.S.)--State University of New York at Binghamton, Department of Physics, Applied Physics and Astronomy, 2009. / Includes bibliographical references.

Archean greenstone belts typically form narrow sheared basins separating bulbous tonalo-trondjhemo-granodioritic (TTG) batholiths. The role played by gravity in the development of such dome-and-keel structures is a key question in Archean tectonics. The Pukaskwa batholith - Hemlo shear zone (HSZ) is a representative example of the dome-and-keel structures that are common in Archean terrains. This region has received considerable attention because the HSZ hosts several major gold deposits that are currently being mined. Late dextral strike-slip kinematics of the HSZ are well recorded by abundant strain markers in greenstone rocks, whereas the quartzofeldspathic coarse-grained rocks of the Pukaskwa batholith bear no macroscopically visible fabric. The goal of this study is to understand the structural history of this greenstone belt-batholith system. The Pukaskwa batholith is a heterogeneous assemblage of TTG gneisses bounded by the Hemlo greenstone belt to the north. The density of the Pukaskwa batholith rocks (density = 2700 kg/m3) is on average less than that of the Hemlo greenstone rocks (density = 3000 kg/m3). Since Archean geotherms were considered higher than modern equivalents, the effective viscosity of the TTG rocks might have been sufficiently low to allow their diapiric ascent through denser greenstone rocks. Alternatively, the emplacement of the TTG batholith might have been driven primarily by transpressive tectonics. The anisotropy of magnetic susceptibility (AMS) provides valuable information on the internal fabric of the Pukaskwa batholith. This study provides the kinematic information needed to support either the diapiric or the transpressive tectonic model. AMS recorded east-west trending prolate and plano-linear fabrics across the northern section along the contact, suggesting that transpressional forces from the Hemlo shear zone affected the emplacement of the Pukaskwa batholith. Away from the contact, fabrics are generally flattened, indicative of doming through diapiric processes. Also, in order to fully evaluate the diapiric hypothesis, it is necessary to obtain reliable data on rock densities across the Pukaskwa batholith. The density of about 360 representative specimens from the Pukaskwa batholith has been measured and will constitute a valuable database for future gravimetric investigations by mining companies. The significant degree of correlation between high-field magnetic susceptibility and density in the Pukaskwa batholith should be taken into account in geophysical exploration in Archean terrains, only as a proxy for iron content.

Este trabalho tem como objetivo desenvolver uma técnica de calculo que permita diagonalizar Hamiltonianos de mais de uma impureza e adaptá-la ao calculo de suas propriedades termodinamicas. Esta técnica é uma extensão do método de grupo de renormalização, originalmente desenvolvido por Wilson para calcular propriedades termodinâmicas do modelo Kondo de uma impureza. O procedimento baseia-se na discretização logarítmica da banda de condução do metal hospedeiro, definida por um parâmetro de discretização &#923, que permite que se projete o Hamiltoniano em uma base quântica finita, na qual o mesmo possa ser diagonalizado numericamente. O tempo do custo computacional do calculo diminui exponencialmente à medida que &#923 cresce, tornando melhor trabalharmos com valores grandes de &#923. O grande problema em usarmos &#923 grande e que aparecem oscilações nas curvas das propriedades termodinâmicas. Neste trabalho apresentamos o método generalizado que elimina essas oscilações. Inicialmente, testamos o método no modelo de Anderson sem correlação de uma impureza para o cálculo da suscetibilidade magnética do sistema, com resultado satisfatório. Na seqüência, para verificar a potencialidade do método, diagonalizamos o Hamiltoniano de Falicov, Kimball e Ramirez (sem spin) do modelo de duas impurezas e calculamos a suscetibilidade de carga da impureza. A motivação para esse cálculo e a equivalência existente entre o Hamiltoniano de Vigman e Finkelshtein e o Hamiltoniano Kondo, para o modelo de uma impureza. No caso de duas impurezas o nosso calculo demonstra que a interação RKKY destrói essa equivalência, ainda que qualitativamente as curvas da suscetibilidade de carga neste modelo reproduzam as de suscetibilidade magnética do modelo Kondo. / This thesis develops an extension of the numerical renormalization - group method. The extended procedure is capable of computing the temperature dependence of the magnetic susceptibility for two-impurity models of dilute magnetic alloys. The renormalization-group approach was devised by Wilson to calculate the thermodynamical properties for the one-impurity Kondo model. The numerical procedure is based on a logarithmic discretization of the conduction band of the metallic host, which is defined by a dimensionless parameter &#923 &#62 1, equal to the ratio of two sucessive discrete energies. Once the conduction Hamiltonian is discretized, the model Hamiltonian reduces to a discrete series that can be diagonalized numerically. The computational cost of the diagonalization diminishes exponentially with 1/ ln &#923, which makes it attractive to work with large &#923. unfortunately, the thermodynamical averages computed with Wilson\'s original version of the numerical renormalization group method and large &#923, computed as function of the temperature, display artificial oscilations with period ln &#923 and amplitude proportional to e-&#9602/ln&#923. By contrast, the generalized procedure in this work produces thermal dependences that converge so rapidly to the continuum (&#923 + 1) limit that curves computed with &#923=10 are virtually identical with those calculated with &#923=3 in the original procedure. As an illustration, we have diagonalized a two-impurity version of the (spinless) Falicov-Kimball-Ramirez Hamiltonian and calculated its charge susceptibility. This application was motivated by the well-established equivalence between the single-impurity (spinless) Vigman-Finkelshtein and Kondo models. In the case of two impurities, our work shows tha the RKKY interaction destroys the equivalence between the two models. Nonetheless, the charge susceptibility curves for the two-impurity Falicov-Kimball-Ramirez model show the qualitative features of the magnetic susceptibility for the two-impurity Kondo model.

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