1,721,094 research outputs found
Two-level magnetovariational measurements for the determination of underground resistivity distributions
No full textSul problema del riconoscimento di uno strato elettricamente polarizzabile mediante misure magnetotelluriche
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On the role of the J-E constitutive relationship in applied geoelectromagnetism
No full textIn current applications of the Induced Polarization (IP) method, the Debye and Cole-Cole models are used to study
relaxation and dispersion properties of rocks, though it is believed that this type of modelisation is confused and
vague, because of the lack of a background physical description. In this paper, we show that the Debye model
can physically be deduced as a consequence of the electrodynamic behaviour of a mixture of bound and unbound
charged particles immersed in an external electric field. We also clarify that the Cole-Cole model is a synthetic
model, which can physically be explained as a continuous distribution of Debye terms.PublishedJCR Journalope
Modeling electrical dispersion phenomena in Earth materials
No full textIt is illustrated that IP phenomena in rocks can be described using conductivity dispersion models deduced as
solutions to a 2nd-order linear differential equation describing the motion of a charged particle immersed in an
external electrical field. Five dispersion laws are discussed, namely: the non-resonant positive IP model, which
leads to the classical Debye-type dispersion law and by extension to the Cole-Cole model, largely used in current
practice; the non-resonant negative IP model, which allows negative chargeability values, known in metals
at high frequencies, to be explained as an intrinsic physical property of earth materials in specific field cases; the
resonant flat, positive or negative IP models, which can explain the presence of peak effects at specific frequencies
superimposed on flat, positive or negative dispersion spectra.159 - 165JCR Journalope
I principi metodologici della magnetellurica su mezzi generalmente dispersivi
No full textJCR Journalope
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Contribution to the definition of the structural model of the Vesuvius by magnetotelluric measurements
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