Fractal approaches in investigating the time dynamics of self-potential hourly variability     

Luciano Telesca  Gerardo Colangelo  Vincenzo Lapenna  Maria Macchiato 《International Journal of Earth Sciences》2005,94(2):285-300

Fractal tools have been used to investigate the time dynamics of hourly self-potential data, recorded during the year 2001 by five geoelectrical stations located in one of the most seismic areas of southern Italy. Scaling behaviour has been revealed by means of different statistics: the Lomb Periodogram method, the Detrended Fluctuation Analysis, the Higuchi analysis and the mean distance spanned within the time L. The values of the scaling exponents estimated by means of these methods indicate that the temporal fluctuations of the geoelectrical signals are not typical of purely random stochastic processes (i.e. white noise), but evidence the presence of long-range correlations. Furthermore, it is found that these correlations are linear.  相似文献   

Monte Ollasteddu, a new gold discovery in the Variscan basement of Sardinia (Italy): first isotopic (40Ar−39Ar, Pb) and fluid inclusion data     

Andrea Dini  Gianfranco Di Vincenzo  Giovanni Ruggieri  Jeffrey Rayner  Pierfranco Lattanzi 《Mineralium Deposita》2005,40(3):337-346

The Monte Ollasteddu deposit represents a major gold discovery in the Variscan basement of southeastern Sardinia. Gold occurs in late-Variscan extensional brittle structures hosted by meta-volcanic, and subordinately meta-sedimentary, rocks. The vein mineralogy is dominated by quartz; arsenopyrite is the main sulphide. Reconnaissance ⁴⁰Ar–³⁹Ar dating gives ages around ∼260 Ma on K-feldspar from mineralized veins, whereas metamorphic white mica from the host rock gives ages clustering at ∼307 Ma. The best age estimate for biotite from a nearby leucogranite body is 286.3±2.2 Ma. The Pb isotope signature of ore and gangue minerals is entirely consistent with literature data for Variscan deposits of Sardinia, and for European Variscan gold deposits. Fluid inclusion data point to the presence of both CO₂-bearing and CO₂-free fluids, with homogenization temperatures ranging from 220 to 415°C, with low-to-moderate salinities (0.4–6.2 wt% NaCl equivalent). Monte Ollasteddu shows several features similar to European Variscan gold deposits; however, the age of mineralization might post-date granitoid intrusion by as much as 30 Ma, being instead coeval with very late calc-alkaline basaltic dykes, marking the transition to a post-orogenic, pre-Tethyan geodynamic setting. Electronic Supplementary Material Supplementary material is available for this article at  相似文献   

Biomonitoring of Trace Metals by Different species of Lichens (Parmelia) in North-West Italy     

Vincenzo Minganti  Renzo Capelli  Giuliana Drava  Rodolfo De Pellegrini  Giorgio Brunialti  Paolo Giordani  Paolo Modenesi 《Journal of Atmospheric Chemistry》2003,45(3):219-229

The concentrations of Cd, Cu, Mn, Ni, Pb, V, and Zn were measured in four different species of lichens (Parmelia caperata, P. pastillifera, P. saxatilis, P. sulcata) sampled in North-West Italy, in order to obtain maps showing metal distribution and the degree of deviation from background (natural) conditions. Significant differences among the species were found for Zn, Mn, Pb and V, suggesting that the combined use of mixed species in biomonitoring surveys can affect the interpretation of results. Results obtained for Parmelia caperata samples have been compared with background (natural) levels, and maps showing the distribution of each metal expressed as deviation from background levels have been obtained. Overall such maps show a medium to high alteration degree in the study area.  相似文献   

Time-clustering analysis of volcanic occurrence sequences     

Luciano Telesca  Vincenzo CuomoVincenzo Lapenna  Maria Macchiato 《Physics of the Earth and Planetary Interiors》2002,131(1):47-62

We investigate the time dynamics of worldwide volcanic activity in order to find the presence of time correlation structures, by applying the Fano factor (FF) method. The analysis, performed on 35 time-occurrence volcanic eruptive sequences with volcanic explosivity index (VEI≥0) has revealed fractal behaviors in the most of the data sets considered, with fractal exponent α ranging from ∼0.2 to 0.9.  相似文献   

Photoelectric photometry and rotation periods of the asteroids 26 Proserpina, 194 Prokne, 287 Nephthys,and 554 Peraga     

Franco Scaltriti  Vincenzo Zappalà 《Icarus》1979,39(1):124-130

We present the photoelectric observations of the asteroids 26 Proserpina, 194 Prokne, 287 Nephthys, and 554 Peraga, performed in the years 1977–1978 at the Astronomical Observatory of Torino. The resulting synodic rotation periods are, for Proserpina, 13^h13; Prokne, 15^h67; and Peraga, 13^h63. The period of Nephthys is possibly ～7^h or the double. A tentative value for the phase coefficient of Peraga was found: 0.043 mag/degree.  相似文献   

Temporal Variations of Benthic Bacterial Microflora on the Northwestern Mediterranean Continental Shelf and Slope     

Daniel  Delille  Laurence D.  Guidi Guy  Cahet 《Marine Ecology》1990,11(2):105-115

Abstract. Bacterial (direct and heterotrophic counts, heterotrophic potentials) and organic matter (org C, org N) parameters were studied over 2 years in the surface sediments of 3 stations located on the continental shelf (station A: 15m; station B: 35m) and slope (station C: 910m) in the northwestern Mediterranean Basin.
Although logistic constraints did not allow a satisfactory sampling periodicity in the offshore survey, some seasonal trends were still observable at the deepest station. Variations were quantitatively more important in the two shallow sediments (from 3×10² heterotrophic bacteria – ml^-1 in December 1984 to 10⁷ heterotrophic bacteria-ml^-1 in March 1986). Epifluorcsccncc direct counts were relatively constant (5×10⁸ cells-ml^-1), while heterotrophic potentials (with ¹⁴C labelled glucose and glutamic acid) showed a succession of very short pulses over the year. Different concentrations of organic matter (from 0.2% orgC at 15m to 0.8% orgC at 35m) appeared to sustain very similar bacterial numbers. Nevertheless, a certain relation between the seasonal evolution of bacterial and organic matter parameters was discernable. Although depth apparently had no measurable effect on maximal spring bacterial densities, it seemed to lessen the summer and winter decreases in the two shallow stations.  相似文献   

Removal of Lead, Copper, Zinc and Cadmium from Water Using Phosphate Rock   总被引：2，自引：0，他引：2  

Alessia CORAMI  Silvano MIGNARDI  Vincenzo FERRINI 《《地质学报》英文版》2008,82(6)

Removal of Pb2 ,Cu~(2 ),Zn~(2 )and Cd~(2 )from aqueous solutions by sorption on a natural phosphate rock(FAP)was investigated.The effects of the contact time and initial metal concentration were examined in the batch method.The percentage sorption of heavy metals from solution ranges generally between 50% and 99%.The amount of sorbed metal ions follows the order Cu>Pb>Cd>Zn. Heavy metal immobilization was attributed to both surface complexation of metal ions on the surface of FAP grains and partial dissolution and precipitation of a heavy metal-containing phosphate.The very low desorption ratio of heavy metals further supports the effectiveness of FAP as an alternative and low-cost material to remove toxic Pb~(2 ),Cu~(2 ),Zn~(2 )and Cd~(2 )from polluted waters.  相似文献   

Design,test and analysis of a light‐weight dissipative bracing system for seismic protection of structures     

Emanuele Renzi  Salvatore Perno  Silvia Pantanella  Vincenzo Ciampi 《地震工程与结构动力学》2007,36(4):519-539

The paper deals with the proposal and the experimental validation of a novel dissipative bracing system for the seismic protection of structures; compared with other similar systems, it is characterized by smaller size and weight, which makes it easier to move and to install, as well as particularly suitable to be inserted in light‐framed structures (e.g. steel structures of industrial plants). The proposed system consists of an articulated quadrilateral with steel dissipaters inserted, to be connected by tendons to frame joints; the prototypes have been designed and realized for the seismic protection of a two‐storey, large‐scale, steel frame, specially designed for shaking‐table tests. The paper, after an illustration of the system, and of its design and behaviour, presents the shaking‐table tests carried out. The experimental results have fully validated the proposed system, showing its good performance in controlling the seismic response of framed structures. A numerical non‐linear model, set up and validated on the basis of the physical tests, has been used to help interpreting the experimental results, but also to perform parametrical studies for investigating the influence of the design parameters on the performance of the control system. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Il ritrovamento dei paleoalvei fluviali con la misura dei potenziali elettrici naturali (P.S.)     

Luigi Vincenzo Patella 《Pure and Applied Geophysics》1958,40(1):85-96

Riassunto L'A. espone un nuovo metodo electtrico dimisura di potenziali elettrocinetici (P.S.), ricordando dapprima i precedenti, per il rapidoritrovamento sperimentale dei paleo-alvei fluviali, e per l'interpretazione delle relative elettrodiagrafie P.S. così ottenute. — L'A. esemplifica per ora i risultati pratici conseguiti altrove, sopratutto in Russia dove l'argomento è stato posto per la prima volta in forma teorica rigorosa, e in una prossima nota completando l'attuale testo esporrà i risultati ottenuti personalmente.

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Summary The A. expounds a new electrical method for measuring electrokinetic potentials (Spontaneous Potentials), touching first upon the previous works, in view of easily refinding experimentally the palaeo river-beds, and interpreting the relating electro-graphics, obtained by these measures. — The A. exemplifies, for the present, the practical results realized elsewhere, particularly in Russia, where the problem has been set down for the first time in a rigorously theoretical way; in a next paper the A., perfecting the present work, will expound the personally attained results.

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Relazione presentata il 10 Aprile 1958 alla Sesta Assemblea Generale della Società Italiana di Geofisica e Meteorologia (Genova: 10–12 Aprile 1958).  相似文献   

Performance of the health facilities during the 2012 Emilia (Italy) earthquake and analysis of the Mirandola hospital case study     

Angelo Masi  Giuseppe Santarsiero  Maria Rosaria Gallipoli  Marco Mucciarelli  Vincenzo Manfredi  Alberto Dusi  Tony Alfredo Stabile 《Bulletin of Earthquake Engineering》2014,12(5):2419-2443

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