1,720,962 research outputs found
Synergic application of different methodologies for the caracterization of aquifers in carbonate rocks
No full textA frequency and time domain approach to analyze springs monitoring data: application on porous and shallow aquifers in mountain areas (Aosta Valley)
Full text linkAquifers in mountain areas are a strategic resource for the people who live there. To optimize future management, it is vital to understand hydrogeological systems from both geological and hydrogeological perspectives. In these aquifers there are often very few wells which permit hydrogeological observation. In great part, therefore, studies on the functioning and hydrodynamics of aquifers have been based on analyzing the hydrograph (depletion and/or recession) or on the complete hydrograph corresponding to an identifiable rainfall event. In order to compensate for this lack of data of the aquifer system analysis in time and frequency domain have been applied. The aim of this paper was to apply these methods, usually applied in karst systems, to small mountain springs supplied by porous and shallow aquifers. The applications of these analysis enable the study of the whole of the hydrographs of the mountain springs and their relationship with the input function (precipitation, essentially), as opposed to many other methods which use only recession or another part of the hydrograph. The methodology proposed treats the series at the time and frequency level, and thus differentiates between short and long periods of rainfall and discharge, which are impossible to differentiate using deconvolution or simple visualization of the unit hydrograph, or with any other method which does not discriminate the spectral variation. The application of this method to six mountain springs, located in the Italy North-Western Alps in the Aosta Valley Region, has served to test the usefulness of these tools in porous and shallow systems. This analysis offers quantifiable and objective criteria for differentiation and comparisons of aquifer systems
Groundwater-level risk assessment by using statistical and geographic information system (GIS) techniques: a case study in the Aosta Valley region, Italy
No full textIn the present study, groundwater-level monitoring has been carried out on 26 observation dug wells in the Aosta Valley region, Italy, during the dry season (June 2013) and wet season (November 2013) in order to assess the water-level fluctuation (WLF). The depth to water level varied from 3.04 to 28.70 metres below ground level (mbgl) in the dry season and from 2.92 to 25.62 mbgl in the wet season. The WLF of the study area varied from 0.01 to 6.80 mbgl, and the western and north-western regions of the study area showed higher WFL. The WLF map was validated with a statistical analysis and elevation value of the area in a geographic information system environment, and this indicated that validation can be accepted for the WLF in the Aosta Valley. The results of the study demonstrated that the eastern region could be considered as a safe and good recharge zone for the groundwater in the Aosta Valley region. The WLF map generated in this study could also be used for the management of future groundwater resources and environmental planning of the area
Analysis and Design of Microwave and Millimeter-wave Passive Devices for Scientific Instrumentation
Full text linkIn the recent astrophysical experiments i.e. QUIET, QUIJOTE, STRIP-LSPE, arrays of polarimeters are used in order to measure the linearly polarized component of the Cosmic Microwave Background Radiation (CMBR). Since the signal of interest is very faint, the sensitivity of the scientific instrumentation should be very high. This goal can be achieved by accommodating a large number of high-performance polarimeters in the focal plane of the antenna. In this perspective, a novel layout of Ortho-Mode-Transducer (OMT) and polarizer, which are key passive waveguide elements of dual-circular polarization polarimeters, have been designed. The polarizer is based on a Dual-Fold-Stub (DFS) design having 20% bandwidth centered at 94.5GHz, whereas the broadband OMT exploits a turnstile junction with 30% bandwidth centered at 94 GHz. The components are realized using the multi-layer technology, where each metallic plate is manufactured by wire spark erosion technique. Using this design methodology, several identical devices can be manufactured in a single machining process. The exploitation of multi-layer technology in conjunction with wire spark erosion technique provides high level of manufacturing repeatability and accuracy along with low cost, making this solution well suitable for the realization of polarimetric arrays consisting of tens/hundreds of chains. The propriety SEM (Spectral Element Method) tool of IEIIT-CNR and commercial EM (Electromagnetic) tools (CST-MWS & HFSS) have been exploited in an effective manner to achieve the required performances. In order to integrate MATLAB with EM tools, COM EM Automation Tool (COM-EM-AT) has been developed and exploited in various manner to attain the final design. The simulation acceleration through distributed computing have also been employed efficiently for tolerance analysis using the SEM too
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
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
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