Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2016-12-27T10:56:51Z No. of bitstreams: 2 Dissertação - Fernando Moreira Viana - 2016.pdf: 6105282 bytes, checksum: 6822f2ad13c8ed286d41535c02c26b87 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-12-27T10:57:33Z (GMT) No. of bitstreams: 2 Dissertação - Fernando Moreira Viana - 2016.pdf: 6105282 bytes, checksum: 6822f2ad13c8ed286d41535c02c26b87 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-12-27T10:57:33Z (GMT). No. of bitstreams: 2 Dissertação - Fernando Moreira Viana - 2016.pdf: 6105282 bytes, checksum: 6822f2ad13c8ed286d41535c02c26b87 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-11-29 / This work proposes a methodology for interpretation of soil resistivity measurements obtained using the arrangement of four electrodesWenner, Schlumberger and Schlumberger-Palmer. Displays can be compared apparent resistivity curves when the quantity used in the abscissa is the effective depth of investigation. This magnitude that depends on the geometry of the electrodes, namely the positioning of both current electrodes and the potential electrodes. The work also features in an innovative way, an algorithm for soil stratification from resistivity measurements obtained with the Schlumberger arrangement. The same is based on the method of complex images and propose a finite number of complex exponentials to represent the kernel function. Several simulations are performed, proving the efficiency and effectiveness of the proposed algorithm. / Este trabalho propõe uma metodologia para interpretação de medições de resistividade do solo obtidas utilizando os arranjos de quatro eletrodos de Wenner, Schlumberger e Schlumberger-Palmer. Mostra ser possível comparar curvas de resistividade aparente quando a grandeza utilizada no eixo das abscissas é a profundidade efetiva de investigação. Grandeza esta que depende da geometria dos eletrodos, ou seja, do posicionamento tanto dos eletrodos de corrente como dos eletrodos de potencial. O trabalho apresenta também, de forma inovadora, um algoritmo para estratificação do solo a partir de medições de resistividade obtidas com o arranjo de Schlumberger. O mesmo baseia-se no método das imagens complexas e na proposição de uma série finita de exponenciais complexas para representar a função kernel. Simulações diversas são realizadas, comprovando a eficiência e a eficácia do algoritmo proposto.

Orientador: Cesar Augusto Moreira / Resumo: A área de estudo está localizada próxima a Caçapava do Sul no estado do Rio Grande do Sul, ocorrência conhecida como Colônia Santa Barbara. A ocorrência está situada na Bacia do Camaquã, alocada estruturalmente em um bloco alto, na interseção de duas falhas com direções NE-SW e NW-SE, com litologias aflorantes pertencentes ao Complexo Metamórfico Bossoroca e Formação Hilário do Grupo Bom Jardim. Descrita entre 1960 e 1970, a pesquisa foi suspensa após análise geoquímica apontar teores de cobre insatisfatórios, não ultrapassando a 1%, sem interesse econômico. Atualmente com uso de aparelhos multi-cabos de aquisição automática é possível a realização de ensaios geoelétricos de diferentes arranjos em menor tempo e maior praticidade, o que impulsionou o desenvolvimento deste trabalho. Essa dissertação apresenta a análise comparativa dos dados de tomografia elétrica em arranjo Schlumberger, Wenner e Dipolo-Dipolo, para averiguar o resultado que descreva a morfologia mais realista esperada do jazimento, baseado no modelo magmático hidrotermal com forte controle estrutural. A análise comparativa entre os arranjos de tomografia elétrica proposta neste trabalho revelou a conformação de um corpo cônico de alta cargabilidade (2,7 mV/V) que engloba o núcleo vertical de alta resistividade (438 Ω.m), além de uma zona anelar de alta cargabilidade possivelmente correlacionada ao sistema de falhas que estruturam o alto estrutural (tufo vulcânico). A estrutura cônica observada é compatível com... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The study area is located near to Caçapava do Sul, at Rio Grande do Sul State, an occurrence known as Colônia Santa Barbara. The occurrence is in the Camaquã Sedimentary Basin, structurally allocated in a high block, at the two faults intersection with NE-SW and NW-SE directions, with outcropping lithologies belonging to Bossoroca Metamorphic Complex, and Hilario Formation. Described between 1960 and 1970, the research was suspended after geochemical analysis pointed to unsatisfactory copper levels, not exceeded 1%, without economic interest. Nowadays, with the use of automatic and multicable devices, like Terrameter Ls, it is possible to perform different arrangements geometric tests in a shorter time and greater practicality, fact that support this work development. This dissertation presents the electrical tomography arrays comparative analysis to Schlumberger, Wenner, and Dipolo-Diplo, to verify the result that describes the most realistic expected deposit morphology, based in a hydrothermal magmatic metallogenetic deposit with high structural control. The comparative analysis revealed a conical body with high chargeability conformation (2,7 mV/V) that encompasses the high resistivity vertical core (438 Ω/m ), as well as an annular portion with high chargeability possibly correlated to the fault zone that structures the central and high block (volcanic tuff). The conical structure observed is compatible with the dike, vertical and cylindrical morphology described for hydr... (Complete abstract click electronic access below) / Mestre

Thesis (M.A.)--University of North Carolina at Wilmington, 2004. / Includes bibliographical references (leaves 93-96).

The Schlumberger array, or Schlumberger, was one of the first resistance arrays to be used to detect buried archaeological features. The early work used fixed probes and widely spaced traverses. Recent simulation work, ýhowever, suggested that the array should give improved resolution and depth penetration over the Twin-Probe array. This thesis is an attempt to operationalise the Schlumberger for use in archaeological prospection. This has been achieved via a co-ordinated use of laboratory simulation and-field studies. Initial fieldwork in England suggested. that the. - use of point electrodes created response patterns that were dependent upon the relative direction of linear targets. This was verified using a simulation tank modified to represent field procedure. The recognition of this response, therefore, required each survey area to be surveyed twice. The re-survey requires the two current probes to be positioned at right angles to the original survey points. The Schlumberger was then used in a battery of methods to investigate the problem of the archaeological interpretation of- small, discrete scatters of ceramic sherds that cover the landscape in Greece. The research has indicated a variation of intra-site patterning that may be significant to the function of these sites. Overall, the results suggest that the relationship between the 'site' and its environment is a complex one, one that can be oversimplified when the ceramic evidence is viewed in isolation. The Schlumberger indicated possible structural elements within some of these sites.

No / The orientation-sensitive performance of the Schlumberger array, when used to survey narrow, linear features, has long been recognized in geophysical prospecting for geology. However, in spite of frequent use of the array for archaeological survey, particularly in eastern Europe and the Far East, this directional effect is not apparent in the survey of walls and ditches. In order to examine the array's performance some experiments were carried out in a shallow electrolytic tank using insulating and conducting cylinders. Broadside and longitudinal traverses with systematic expansion of the current electrode spacing facilitated the production of pseudosections. The results confirmed the high selectivity of the Schlumberger response to the orientation of the feature. Broadside traverse of the conductor and longitudinal traverse of the insulator produced very large changes: much smaller signals were recorded for the alternative orientations. A subsequent experiment, however, on a simulated ditch in bedrock revealed no signal. The directional effect for a linear insulator was confirmed in field studies of a simple stone-walled structure. Implications for survey of low-contrast linear archaeological features are discussed.

The Schlumberger array, or Schlumberger, was one of the first resistance arrays to be used to detect buried archaeological features. The early work used fixed probes and widely spaced traverses. Recent simulation work, ýhowever, suggested that the array should give improved resolution and depth penetration over the Twin-Probe array. This thesis is an attempt to operationalise the Schlumberger for use in archaeological prospection. This has been achieved via a co-ordinated use of laboratory simulation and-field studies. Initial fieldwork in England suggested. that the. - use of point electrodes created response patterns that were dependent upon the relative direction of linear targets. This was verified using a simulation tank modified to represent field procedure. The recognition of this response, therefore, required each survey area to be surveyed twice. The re-survey requires the two current probes to be positioned at right angles to the original survey points. The Schlumberger was then used in a battery of methods to investigate the problem of the archaeological interpretation of- small, discrete scatters of ceramic sherds that cover the landscape in Greece. The research has indicated a variation of intra-site patterning that may be significant to the function of these sites. Overall, the results suggest that the relationship between the 'site' and its environment is a complex one, one that can be oversimplified when the ceramic evidence is viewed in isolation. The Schlumberger indicated possible structural elements within some of these sites.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-02-02T12:43:27Z No. of bitstreams: 1 JerbesonDeMeloSantana_DISSERT.pdf: 783968 bytes, checksum: 867f9ad936c5adb69bb954b107ba3e2d (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-02-07T19:13:20Z (GMT) No. of bitstreams: 1 JerbesonDeMeloSantana_DISSERT.pdf: 783968 bytes, checksum: 867f9ad936c5adb69bb954b107ba3e2d (MD5) / Made available in DSpace on 2017-02-07T19:13:20Z (GMT). No. of bitstreams: 1 JerbesonDeMeloSantana_DISSERT.pdf: 783968 bytes, checksum: 867f9ad936c5adb69bb954b107ba3e2d (MD5) Previous issue date: 2015-04-16 / ? apresentado um novo m?todo para o mapeamento aproximado da resistividade em subsuperf?cie usando uma abordagem geoestat?stica. S?o utilizados os pontos caracter?sticos (PCs) de uma sondagem de resistividade, que s?o os seus pontos de inflex?o e de extremos (m?ximos e m?nimos). O m?todo consiste basicamente de quatro etapas: i) suavizar ou interpolar as sondagens el?tricas, ii) obter os PCs usando as vers?es suavizadas das sondagens el?tricas, bem como obter as estimativas pontuais para a resistividade em subsuperf?cie usando rela??es emp?ricas entre os espa?amento de eletrodo e profundidade, iii) calcular os semivariogramas associados ?s estimativas pontuais de resistividade, e ajustar os mesmos a um modelo de semivariograma te?rico, e, finalmente, iv) estimar a distribui??o da resistividade em subsuperf?cie por krigagem utilizando as estimativas pontuais. N?o ? feita nenhuma hip?tese sobre a resistividade verdadeira e, como resultado, o m?todo ? robusto ? dimens?o do modelo e pode ser implementado para qualquer dimens?o. Computacionalmente, o m?todo ? muito r?pido porque nenhuma modelagem (direta ou inversa) ? realizada e o custo computacional ? apenas o da krigagem. Dada a sua robustez a erros de medi??o e ? dimens?o do modelo, o m?todo pode ser implementado como uma t?cnica r?pida e autom?tica de interpreta??o. A distribui??o de resistividade estimada tem valor tanto como um objeto de interpreta??o quanto como um modelo inicial de melhor qualidade para inicializar os algoritmos de invers?o. Neste ?ltimo uso, cerca de 30% a 40% das itera??es podem ser poupadas em compara??o com a inicializa??o com o semiespaco homog?neo, para o caso dos algoritmos de invers?o 2D que incorporam a restri??o de suavidade. O desempenho do m?todo ? demonstrado com aplica??es com dados 2D sint?ticos e reais no arranjo Schlumberger. A abordagem proposta pode ser generalizada para outras m?todos de resistividade DC e m?todos eletromagn?ticos que se baseiam em sondagens de resistividade. / It is presented a new method for the approximate mapping of the subsurface resistivity based on a geostatistical approach. It are used the characteristic points (CPs) of a resistivity sounding, which are their inflection and extreme (maximum and minimum) points. The methodology consists basically of four stages: i) smoothing the geoelectric soundings to assure robusteness to measurement errors, ii) determining the CPs from the smoothed versions of the geoelectric soundings, and obtaining from the CPs point estimates for the subsurface resistivity using empirical relations between electrode spacing and depth, iii) calculating semivariograms associated to the point estimates, and fitting them to a semivariogram model, and finally iv) estimating the subsurface resistivity distribution by kriging interpolation of the point estimates. No assumptions are made about the true subsurface resistivity and, as result, the method is robust to the model dimension and can be implemented for any dimension. Computationally, the method is very fast because no modeling (either direct or inverse) is demanded and the most intensive computer operation is just a kriging interpolation. Given its robustness to measurement errors and model dimension, it can be implemented as a fast automatic method of interpretation. The estimated resistivity distribution has value both as an object to interpret and as a better initial model for inversion algorithms. In the latter use, about 30%-40% of the iterations can be saved when compared with initializations with the homogeneous semispace, for 2D algorithms incorporating the classic smoothness constraint, for example. The method?s performance is demonstrated with applications with 2D Schlumberger array data both for synthetic and real cases. The proposed method might be generalized for other DC-resistivity arrays and electromagnetic techniques based on apparent resistivity soundings.

This diploma thesis deals with research and study of soil impedance measurement and soil resistivity. Currently, the issue of measuring and determining soil resistance is ensured through the gradual measurement of certain soil parameters at individual points of the surface (or depth of the ground). This thesis focuses on the idea of measuring soil resistance on a certain area using a network of electrodes through a suitably designed test, measurement and evaluation system. Such an approach may find application in the need to determine soil parameters (such as resistivity) on a specific demarcated area (or depth). The prospect of such an application can be seen in saving time, energy and money needed to measure the soil resistivity of a certain area (as opposed to gradual point measurements). The configuration possibilities of OMICRON CPC 100 measuring instrument were used for the design and implementation of the measuring system for the mentioned purpose. The work is completed by verification of the proposed solution by real measurement with evaluation of the results.