PARAMETER SENSITIVITY MAPS OF SURFACE GEOELECTRIC ARRAYS II. NONLINEAR AND FOCUSSED ARRAYS

In this paper we present, at first time in a geophysical journal, parameter sensitivity maps of nonlinear and focussed electrode arrays. We present them as anomalies due to electric dipoles forming on opposing surfaces of an elementary cube within the subsurface at three different depths, and not only the total effect of the dipole, but also of its components are shown. Parameter sensitivity maps of non-linear arrays, compared to those of linear arrays, have in general 1. more equal sensitivity values in x and y directions, 2. more chances for antisymmetry axes, 3. smoother lateral distribution of sensitivity values. We recommend a systematic use of parameter sensitivity maps in geoelectric prospecting, both in planning and interpretation of field measurements

Auxiliary Results of Collection and Classification of Surface Geoelectric Arrays

Recently, we have made a classification of more than one hundred various surface geoelectric arrays ever published in geophysical literature (Szalai and Szarka 2007a, 2007b). The classification is based on three divalent parameters (as “superposition” of measurements, “focusing” of currents and “colinearity” of the array), thus we set up eight groups of geoelectric arrays. One further group was separated for about 10 socalled “composite” arrays, which cannot be classified in the aforementioned way. Here we present some application examples of the classification results. Namely, we call the attention to some hidden relationships among geoelectric arrays: (1) we give an illustration how various arrays can be derived from their root array (besides the Schlumberger-related arrays several other examples will also be given in the presentation); (2) we provide a summary of arrays, capable to measure various partial derivatives of the electric potential. Among the 21 arrays 14 are already published arrays, but there are seven possible, but not-yet-applied arrays. In this way, such missing links in the genealogic trees may lead to creation of reasonable and purposeful new arrays

INDICATION OF META-ANTHRACITE BY MAGNETOTELLURICS IN THE KŐSZEG-RECHNITZ PENNINIC WINDOW : A TEST AREA

One of the Penninic Nappes is the Kőszeg-Rechnitz (K-R) tectonic window at the Eastern end of the Eastern Alps. It has a complicated metamorphic history from the Jurassic time. The organic material of the Penninic Ocean was transformed to electrically conductive meta-anthracite. Its amount in the chalcophyllite is estimated by geochemists to 0.2 per cent. Taking this conducting structure as a test area pilot deep magnetotelluric (MT) soundings have been carried out and we determined - the structure of the conductivity anomaly due to 0.2 per cent meta anthracite in the K-R window and its surroundings - the different kinds of MT distortions as lateral (side) effect of the conductor appearing in the crust and mantle - the most probable depth of the conductive asthenosphere at the border of the Pannonian Basin (having extreme shallow asthenosphere). The obtained ~140 km depth is in correlation with value of the asthenospheric map based mainly on seismic data

Depth of Investigation of Dipole-dipole, Noncolinear and Focused Geoelectric Arrays

Investigation depth of various DC geoelectric arrays has always been in the focus of interest of geoelectricians. According to its classical definition (Roy and Apparao 1971), the depth of investigation is the depth of the maximum response due to a horizontal thin-sheet embedded in a half-space, by using a given geoelectric array. On basis of the graph of the thin-sheet response as a function of the depth (from the so-called „depth of investigation characteristics” or DIC function) Edwards (1977) found more realistic to compute the medium depth than the depth of the maximum response. DIC functions have been known so far only for simple colinear arrays, the dipole equatorial array and two focused arrays. Here we provide a summary about the depth of investigation values of various dipole-dipole arrays (for parallel, perpendicular, radial, azimuthal ones), and for the most important noncolinear and focused arrays. Depth of investigation values are computed from both approaches. DIC functions (obtained by a new analytical formula) are also presented, as illustrations. The analytical formula can be used to compute DIC function of any surface geoelectric array. A systematic interpretation of the resulting depth of investigation values provides simple but useful thumb-rules for practical applications

Classification of Surface Geoelectric Arrays

We have found in the geophysical literature more than ninety different surface geoelectric arrays, fulfilling an updated definition (specifying the current feeding, the potential difference measurement and the geometry of the electrodes). Several composite configurations, with widely varying geometry, have also been collected. We have presented the geoelectric arrays in a systematic way and with a unified notation. The classification is based on three divalent parameters: “superposition” of measurements, “focusing” of currents and “colinearity” of the array, creating 8 groups of geoelectric arrays. For the simplest group (the group of nonfocused, nonsuperposed, colinear arrays) we cover all theoretically possible arrays. For the other groups – due to the infinite variety – we collected only the already existing arrays, but it is easy to create further example arrays. The proposed classification may facilitate a systematic comparison of properties of different arrays and inspire testing new arrays, to find optimal configurations for actual field problems. Finally, the classification certainly helps to avoid rediscovering already published arrays

Application of direct bioautography and SPME-GC-MS for the study of antibacterial chamomile ingredients

The isolation and characterization of antibacterial chamomile components were performed by the use of direct bioautography and solid phase microextraction (SPME)-GC-MS. Four ingredients, active against Vibrio fischeri, were identified as the polyacetylene geometric isomers cis- and trans-spiroethers, the coumarin related herniarin, and the sesquiterpene alcohol (-)-alpha-bisabolol

Innovation and New Path Creation: The Role of Niche Environments in the Development of the Wind Power Industry in Germany and the UK

This paper seeks to explore the issues of innovation and new path creation in the UK and Germany, illustrated through the case of the modern wind power industry. Taking an evolutionary perspective drawing on path dependence theory, the paper examines the role of niche environments in the creation of new economic pathways. The research finds that new economic pathways are more likely to develop in places where niche conditions provide receptive environments for innovations to flourish. The policy implications of the research include the importance of supporting niche environments that encourage growth in new sectors and the need for financial support to bring innovations to market, to encourage the development of new economic pathways