1,721,023 research outputs found
Soil-Gas Geochemistry as Permeability Tracer of Thermally Altered Clays at Orciatico (Tuscany, Central Italy)
No full textThe physical properties of clay allow to consider argillaceous formations as geological barriers to radionuclide migration in high-level radioactive-waste isolation systems. As laboratory simulations are short term and numerical models always involve assumptions and simplifications of the natural system, natural analogues are extremely attractive surrogates for the study of long-term isolation.
The thermally altered clays of the Orciatico area (Tuscany, Central Italy) represent an interesting natural model of a heat source which acted on argillaceous materials. The study of this natural analogue was performed through detailed geoelectrical and soil-gas surveys in order to define both the geometry of the intrusive body and the gas permeability of a clay unit characterized by different thermal alteration degrees. In particular, soil-gas radon and carbon dioxide distributions highlighted that the clay sequences, in spite of their thickness and plasticity, if fractured and metamorphosed, form a lesser impermeable barrier for naturally migrating gas.European CommissionUnpublishedLuxembourg4.5. Studi sul degassamento naturale e sui gas petroliferiope
Soil-Gas Geochemistry as Permeability Tracer of Thermally Altered Clays at Orciatico (Tuscany, Central Italy)
No full textThe physical properties of clay allow to consider argillaceous formations as geological barriers to radionuclide migration in high-level radioactive-waste isolation systems. As laboratory simulations are short term and numerical models always involve assumptions and simplifications of the natural system, natural analogues are extremely attractive surrogates for the study of long-term isolation.
The thermally altered clays of the Orciatico area (Tuscany, Central Italy) represent an interesting natural model of a heat source which acted on argillaceous materials. The study of this natural analogue was performed through detailed geoelectrical and soil-gas surveys in order to define both the geometry of the intrusive body and the gas permeability of a clay unit characterized by different thermal alteration degrees. In particular, soil-gas radon and carbon dioxide distributions highlighted that the clay sequences, in spite of their thickness and plasticity, if fractured and metamorphosed, form a lesser impermeable barrier for naturally migrating gas.European CommissionUnpublishedLuxembourg4.5. Studi sul degassamento naturale e sui gas petroliferiope
Soil gas geochemistry: significance and application in geological prospectings
No full textGas-geochemistry has been proven to be a reliable and simple technique to apply, at different scales, in many geological scenarios. The study of spatial distribution of soil-gas anomalies, at the surface, can give important and interesting information on the origin and processes involving deep and superficial gas species. This information can be applied and studied in different frameworks, for example: I) seismic zonation, examining, at the surface, anomalous concentrations of deep gas species that upraise throughout preferential pathways (faults and/or fractures); II) environmental protection, monitoring naturally occurring toxic gases and highlighting zones with high health risks for humans; III) geomorphological and structural research, detecting the aggressive fluid piping that causes carsic phenomena; IV) radionuclide migration, both in the pollution assessment from abandoned uranium mines and in the study of high-level radioactive-waste isolation systems.
Soil-gas distribution could be affected by surface features such as pedological, biogenic and meteorological factors: these are supposed to have only a subordinate effect on gas leakage. However, it is possible to properly interpret soil-gas anomalies and recognize, and avoid, influences of surface features studying the association of different gases (with different origin and physical/chemical behavior), collecting a large number of samples during periods of stable meteorological and soil moisture conditions (e.g., during dry season) and using appropriate statistical treatment of data (i.e., experimental variograms to investigate the spatial dependency of gas concentrations).
We will try, in this paper, to give hints for a better comprehension of the main mechanisms ruling soil-gas features both displaying and discussing some data obtained in either prospecting or monitoring case studies.
Soil-gas geochemistry involves the study of many gaseous species (i.e., radiogenic, trace and diagenetic gases) each of them can give specific information on the conditions that allow their formation, accumulation and/or migration. In this study, we outline the results from two analyzed soil-gases: radon (222Rn), a radiogenic trace gas, and carbon dioxide (CO2) which generally acts as carrier for trace gases.Published183-2044.5. Studi sul degassamento naturale e sui gas petroliferiope
Soil gas geochemistry for the study of far- and near-field gas migration mechanisms.
No full textDetailed soil-gas surveys have been conducted at two mine districts to better comprehend gas migration mechanisms from deposits buried at different depths. The Tolfa (Lazio, Central Italy) and Neves-Corvo (Baixo Alentejo, Portugal) mine districts have different characteristics: the former is superficial (30-100 m) while the latter is located at a depth of 400-500 m and covered by low-permeability metamorphic rocks. The soil-gas results from these two different investigated areas provide interesting results related to the study of far- and near-field gas migration mechanisms. In particular, the anomalous concentrations of sulphur compounds (COS, CS2 e SO2), CO2, and Rn confirmed the presence of the two ore deposits. Furthermore, radon was found to be sensitive to soil permeability variations and to be associated with migration pathways (faults and/or fractures). Overall the results indicate the potential for using the studied gas species as indicators of deep seated ore deposits (i.e. in the Neves-Corvo mine district), even at locations where there is thick overburden and no surface evidence.Submitted4.5. Studi sul degassamento naturale e sui gas petroliferiJCR 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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
The October 31 (Ml 5.4) and November 1 (Ml 5.0) Molise earthquake (southern Italy): first results from geochemistry.
No full textTwo geochemical surveys have been performed in November and December 2002 in the Molise region (southern Italy) and surrounding areas struck by two moderate size earthquakes on October 31 (M_l 5.4) and on November 1 (M_l 5.3). The main goals of this study were: i) to highlight eventual variations either in the physico-chemical features or in the chemistry of thermo-mineral and cold springs (already sampled in 1997) discharging in an area located 50 km far from the epicentral one (Sannio-Matese, Campania region),; ii) to determine the chemical features of the groundwater discharging in the epicentral area, identifying the location and the extension of the various existing aquifers; iii) to collect information about eventual changes occurred in springs and wells (variations in flows, groundwater level in wells, etc.). Moreover, twice a week samplings have been carried out for two months at two important sulphurous springs (Larino spring, in the epicentral area and Telese thermo-mineral spring, in the Sannio area) in order to gather temporal chemical trend during the ongoing seismicity. We sampled a total of 35 sites (8 springs and wells in the Sannio-Matese area and 27 in the epicentral one) measuring in the field: temperature, pH, Eh, electrical conductivity, as well as radon, bicarbonate and H_2S contents. In laboratory, analyses of major, minor and trace elements have been performed, together with dissolved gas compositions. On 10 selected samples δ13C and 87/86Sr analyses are in progress. Data collected in the second survey show, for springs and wells located in the epicentral area, an evident pH and Eh increase (probably they returned to normal pre-earthquake values) together with some chemical variations; on the contrary, springs located in the Sannio-Matese area showed no variations. Local people observed sin-earthquake flow increases and variations in turbidity in two springs discharging in the epicentral area. All detected groundwater changes are discussed either with the seismological features of the two main shocks (depth, style of faulting) or with the geological setting of the hit area
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Is Panarea Island (Italy) a valid and cost-effective natural laboratory for the development of detection and monitoring techniques for submarine CO2 seepage?
No full textDeveloping reliable detection and monitoring techniques for underwater CO2 seepage and its effects on the marine environment is important for a wide range of topics; for example: volcanic surveillance, risk assessment of potential leakages from sub-seabed CO2 storage sites, and to forecast the effects of ocean acidification. A novel approach is to use areas where natural release of CO2 is present as ‘field-laboratories’ for validation of CO2 monitoring techniques and procedures. One such area was identified close to the volcanic island of Panarea (Italy). Here, CO2 seeps from the seafloor in shallow water allowing scuba divers to collect the needed data. Moreover, the coastal setting allows use of small boats for the marine operations, thus strongly reducing the costs. The applied study techniques examined are mainly sampling methods for free and dissolved gases, direct measurement of the CO2 fluxes, pH measurement along the water column, and verification of the impact of CO2 on the local environment. From these first results, the submarine degassing area of Panarea can be realistically considered a natural laboratory where it is possible to test and validate detection methods for the prompt identification of potential seepage from sub-seabed CO2 storage areas. The particularly favorable environment permits the use of simplified logistics, thus reducing the costs of the research to almost negligible values if compared with any high-seas operation.Published200-2104.5. Studi sul degassamento naturale e sui gas petroliferiN/A or not JCRreserve
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