The Experts below are selected from a list of 14532 Experts worldwide ranked by ideXlab platform

Alain Tabbagh - One of the best experts on this subject based on the ideXlab platform.

  • Interpretation of slingram conductivity mapping in near‐surface geophysics: using a single parameter fitting with 1D model
    Geophysical Prospecting, 1996
    Co-Authors: Roger Guérin, Y. Méhéni, G. Rakotondrasoa, Alain Tabbagh
    Abstract:

    Electrical conductivity mapping is a prerequisite tool for hydrogeological or environmental studies. Its interpretation still remains qualitative but advantages can be expected from a quantitative approach. However a full 3D interpretation is too laborious a task in comparison with the limited cost and time which are involved in the majority of such field studies. It is then of value to define the situations where lateral variations are sufficiently smooth for a 1D model to describe correctly the underlying features. For slingram conductivity measurements, criteria allowing an approximate 1D inversion are defined: these mainly consist of a limited rate of variation over three times the intercoil spacing. In geological contexts where the weathering has generated a conductive intermediate layer between the underlying Sound Rock and the soil, this processing can be applied to determine the thickness of the conductive layer from the apparent resistivity map when the other geoelectrical parameters are known. The examples presented illustrate this application.

  • Interpretation of slingram conductivity mapping in near-surface geophysics: using a single parameter fitting with 1D model1
    Geophysical Prospecting, 1996
    Co-Authors: Roger Guérin, Y. Méhéni, G. Rakotondrasoa, Alain Tabbagh
    Abstract:

    Electrical conductivity mapping is a prerequisite tool for hydrogeological or environmental studies. Its interpretation still remains qualitative but advantages can be expected from a quantitative approach. However a full 3D interpretation is too laborious a task in comparison with the limited cost and time which are involved in the majority of such field studies. It is then of value to define the situations where lateral variations are sufficiently smooth for a 1D model to describe correctly the underlying features. For slingram conductivity measurements, criteria allowing an approximate 1D inversion are defined: these mainly consist of a limited rate of variation over three times the intercoil spacing. In geological contexts where the weathering has generated a conductive intermediate layer between the underlying Sound Rock and the soil, this processing can be applied to determine the thickness of the conductive layer from the apparent resistivity map when the other geoelectrical parameters are known. The examples presented illustrate this application.

Roger Guérin - One of the best experts on this subject based on the ideXlab platform.

  • Interpretation of slingram conductivity mapping in near‐surface geophysics: using a single parameter fitting with 1D model
    Geophysical Prospecting, 1996
    Co-Authors: Roger Guérin, Y. Méhéni, G. Rakotondrasoa, Alain Tabbagh
    Abstract:

    Electrical conductivity mapping is a prerequisite tool for hydrogeological or environmental studies. Its interpretation still remains qualitative but advantages can be expected from a quantitative approach. However a full 3D interpretation is too laborious a task in comparison with the limited cost and time which are involved in the majority of such field studies. It is then of value to define the situations where lateral variations are sufficiently smooth for a 1D model to describe correctly the underlying features. For slingram conductivity measurements, criteria allowing an approximate 1D inversion are defined: these mainly consist of a limited rate of variation over three times the intercoil spacing. In geological contexts where the weathering has generated a conductive intermediate layer between the underlying Sound Rock and the soil, this processing can be applied to determine the thickness of the conductive layer from the apparent resistivity map when the other geoelectrical parameters are known. The examples presented illustrate this application.

  • Interpretation of slingram conductivity mapping in near-surface geophysics: using a single parameter fitting with 1D model1
    Geophysical Prospecting, 1996
    Co-Authors: Roger Guérin, Y. Méhéni, G. Rakotondrasoa, Alain Tabbagh
    Abstract:

    Electrical conductivity mapping is a prerequisite tool for hydrogeological or environmental studies. Its interpretation still remains qualitative but advantages can be expected from a quantitative approach. However a full 3D interpretation is too laborious a task in comparison with the limited cost and time which are involved in the majority of such field studies. It is then of value to define the situations where lateral variations are sufficiently smooth for a 1D model to describe correctly the underlying features. For slingram conductivity measurements, criteria allowing an approximate 1D inversion are defined: these mainly consist of a limited rate of variation over three times the intercoil spacing. In geological contexts where the weathering has generated a conductive intermediate layer between the underlying Sound Rock and the soil, this processing can be applied to determine the thickness of the conductive layer from the apparent resistivity map when the other geoelectrical parameters are known. The examples presented illustrate this application.

Carlos Figueiredo - One of the best experts on this subject based on the ideXlab platform.

  • Texture Analysis of Grey-Tone Images by Mathematical Morphology: A Nondestructive Tool for the Quantitative Assessment of Stone Decay
    Mathematical Geology, 2000
    Co-Authors: António Maurício, Carlos Figueiredo
    Abstract:

    Both a low-cost and easily handled nondestructive methodology and its validation criterion are proposed. The methodology is based on image analysis by mathematical morphology for the assessment of decayed stone surfaces in historic limestone buildings. It is adapted to follow the evolution, at macroscopic time and space scales, of stone materials used in art pieces and monument building stones. This methodology is applied to the quantitative analysis of textures of static grey-tone CCD video camera images representative of flat stone structures that cannot be handled. These structures line the walls inside an important church, Basílica da Estrela, built in the 18th century and located in the city of Lisbon. Detailed visual/tactile observation shows that these flat vertical structures are more or less damaged depending on their position inside the church. The damage is possibly associated with different environment conditions both from the atmosphere inside the church and from contact with the walls of the church. The presence of these pathologies breaks down the order and organization of Sound Rock textures introducing changes in the topographical and optical characteristics of the texture of the surfaces. This new methodology is based on the granulometry and covariance analysis of grey-tone images corresponding to the structures studied. The validation criterion allows the results of the proposed methodology to be compared to the results of a previous qualitative study made by experts in the field using visual assessment and monument mapping as a valid methodology to assess the degree of decay. This procedure is based on optical and topographical characteristics and type of decay of the stone surface, and the quantity of material lost from the surface of the panels during the year. As discussed in this paper, in the context of cultural heritage, the proposed methodology was validated and its results can be considered an improvement on and complementary to expert visual analysis and also to other nondestructive techniques.

Y. Méhéni - One of the best experts on this subject based on the ideXlab platform.

  • Interpretation of slingram conductivity mapping in near‐surface geophysics: using a single parameter fitting with 1D model
    Geophysical Prospecting, 1996
    Co-Authors: Roger Guérin, Y. Méhéni, G. Rakotondrasoa, Alain Tabbagh
    Abstract:

    Electrical conductivity mapping is a prerequisite tool for hydrogeological or environmental studies. Its interpretation still remains qualitative but advantages can be expected from a quantitative approach. However a full 3D interpretation is too laborious a task in comparison with the limited cost and time which are involved in the majority of such field studies. It is then of value to define the situations where lateral variations are sufficiently smooth for a 1D model to describe correctly the underlying features. For slingram conductivity measurements, criteria allowing an approximate 1D inversion are defined: these mainly consist of a limited rate of variation over three times the intercoil spacing. In geological contexts where the weathering has generated a conductive intermediate layer between the underlying Sound Rock and the soil, this processing can be applied to determine the thickness of the conductive layer from the apparent resistivity map when the other geoelectrical parameters are known. The examples presented illustrate this application.

  • Interpretation of slingram conductivity mapping in near-surface geophysics: using a single parameter fitting with 1D model1
    Geophysical Prospecting, 1996
    Co-Authors: Roger Guérin, Y. Méhéni, G. Rakotondrasoa, Alain Tabbagh
    Abstract:

    Electrical conductivity mapping is a prerequisite tool for hydrogeological or environmental studies. Its interpretation still remains qualitative but advantages can be expected from a quantitative approach. However a full 3D interpretation is too laborious a task in comparison with the limited cost and time which are involved in the majority of such field studies. It is then of value to define the situations where lateral variations are sufficiently smooth for a 1D model to describe correctly the underlying features. For slingram conductivity measurements, criteria allowing an approximate 1D inversion are defined: these mainly consist of a limited rate of variation over three times the intercoil spacing. In geological contexts where the weathering has generated a conductive intermediate layer between the underlying Sound Rock and the soil, this processing can be applied to determine the thickness of the conductive layer from the apparent resistivity map when the other geoelectrical parameters are known. The examples presented illustrate this application.

G. Rakotondrasoa - One of the best experts on this subject based on the ideXlab platform.

  • Interpretation of slingram conductivity mapping in near‐surface geophysics: using a single parameter fitting with 1D model
    Geophysical Prospecting, 1996
    Co-Authors: Roger Guérin, Y. Méhéni, G. Rakotondrasoa, Alain Tabbagh
    Abstract:

    Electrical conductivity mapping is a prerequisite tool for hydrogeological or environmental studies. Its interpretation still remains qualitative but advantages can be expected from a quantitative approach. However a full 3D interpretation is too laborious a task in comparison with the limited cost and time which are involved in the majority of such field studies. It is then of value to define the situations where lateral variations are sufficiently smooth for a 1D model to describe correctly the underlying features. For slingram conductivity measurements, criteria allowing an approximate 1D inversion are defined: these mainly consist of a limited rate of variation over three times the intercoil spacing. In geological contexts where the weathering has generated a conductive intermediate layer between the underlying Sound Rock and the soil, this processing can be applied to determine the thickness of the conductive layer from the apparent resistivity map when the other geoelectrical parameters are known. The examples presented illustrate this application.

  • Interpretation of slingram conductivity mapping in near-surface geophysics: using a single parameter fitting with 1D model1
    Geophysical Prospecting, 1996
    Co-Authors: Roger Guérin, Y. Méhéni, G. Rakotondrasoa, Alain Tabbagh
    Abstract:

    Electrical conductivity mapping is a prerequisite tool for hydrogeological or environmental studies. Its interpretation still remains qualitative but advantages can be expected from a quantitative approach. However a full 3D interpretation is too laborious a task in comparison with the limited cost and time which are involved in the majority of such field studies. It is then of value to define the situations where lateral variations are sufficiently smooth for a 1D model to describe correctly the underlying features. For slingram conductivity measurements, criteria allowing an approximate 1D inversion are defined: these mainly consist of a limited rate of variation over three times the intercoil spacing. In geological contexts where the weathering has generated a conductive intermediate layer between the underlying Sound Rock and the soil, this processing can be applied to determine the thickness of the conductive layer from the apparent resistivity map when the other geoelectrical parameters are known. The examples presented illustrate this application.