Andamento diurno,stagionale ed annuo della visbillità nel Golfo di Trieste     

Prof. Silvio Polli 《Pure and Applied Geophysics》1952,21(1):63-70

Riassunto Dalle osservazioni di visibilità verso il mare, eseguite giornalmente a Trieste alle ore 8, 14 e 19, nel ventennio 1931–1950, si deducono le medie mensili, stagionali e annue. La visibilità risulta massima alle ore 14 e nei mesi estivi. Il valore medio annuo è 6.5 del codice internazionale, la visibilità è di 15.000 m ed è classificata mediocre-buona. Nel ventennio l'andamento medio annuo risulta leggermente crescente.

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Summary From the visibility-observations towards the sea, effectuated every day at 8^h, 14^h and 19^h, during the period of twenty years (1931–1950), the monthly and annual mean values are calculated. The visibility results maximum at 14^h of the summer months. The mean annual value is 6.5 of the International Codex, the visibility is 15.000 m and it is classified middle-good. In the twenty years 1931–1950, the mean annual going results lightly increasing.

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Punica granatum Shell Preparation,Characterization, and Use for Crystal Violet Removal from Aqueous Solution          下载免费PDF全文

Marilice B. Silveira  Flávio A. Pavan  Nilton F. Gelos  Eder C. Lima  Silvio L. P. Dias 《洁净——土壤、空气、水》2014,42(7):939-946

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Sediment geochemistry of the urban Lake Paulo Gorski     

Marcelo Bevilacqua Remor  Silvio César Sampaio  Sacha de Rijk  Marcio Antônio Vilas Boas  Jackeline Tatiane Gotardo  Everton Tiago Pinto  Fábio Augusto Schardong 《国际泥沙研究》2018,33(4):406-414

The objective of this study was to evaluate the concentration and distribution of heavy metals in the sediments of Paulo Gorski Lake, as well as the metals’ bioavailability and potential ecological risk, and to define the anthropogenic and natural heavy metal contributions to the lake. The chemical elements calcium (Ca), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), nickel (Ni), lead (Pb), and zinc (Zn) were quantified by flame atomic absorption spectrophotometry with two extraction methods to quantify the bioavailable and non-bioavailable fractions. The data were evaluated using multivariate statistics and sediment quality indices. All sediment collection points (S1, S2, S3, S4 and S5) are different in terms of the concentration of heavy metals, except for S4 and S5, which were statistically equal. The bioavailable fraction of the elements in the sediment follows the sequence Pb>Cu>Mn>Zn>Ni>Cr>phosphorus (P) for all points. The elements Co, Cr, Pb, and Zn showed moderate to considerable contamination at all points. Only points S3 and S5 had moderate ecological risk. Urbanization has been affecting Paulo Gorski Lake via the input of chemical elements, especially Co and Pb. The points most affected by heavy metal contamination are S3 and S5 when the sedimentological sensitivity factor is considered. The lake has high hydrodynamics, causing some of the contaminants that enter the system to leave it, leading to potential negative impacts downstream.  相似文献   

Late Holocene sea-surface temperature and precipitation variability in northern Patagonia, Chile (Jacaf Fjord, 44°S)     

Julio Sepúlveda  Silvio Pantoja  Konrad A. Hughen  Sbastien Bertrand  Dante Figueroa  Tania Len  Nicholas J. Drenzek  Carina Lange 《Quaternary Research》2009,72(3):400-409

A high-resolution multi-proxy study including the elemental and isotopic composition of bulk organic matter, land plant-derived biomarkers, and alkenone-based sea-surface temperature (SST) from a marine sedimentary record obtained from the Jacaf Fjord in northern Chilean Patagonia (44°20′S) provided a detailed reconstruction of continental runoff, precipitation, and summer SST spanning the last 1750 yr. We observed two different regimes of climate variability in our record: a relatively dry/warm period before 900 cal yr BP (lower runoff and average SST 1°C warmer than present day) and a wet/cold period after 750 cal yr BP (higher runoff and average SST 1°C colder than present day). Relatively colder SSTs were found during 750–600 and 450–250 cal yr BP, where the latter period roughly corresponds to the interval defined for the Little Ice Age (LIA). Similar climatic swings have been observed previously in continental and marine archives of the last two millennia from central and southern Chile, suggesting a strong latitudinal sensitivity to changes in the Southern Westerly Winds, the main source of precipitation in southern Chile, and validating the regional nature of the LIA. Our results reveal the importance of the Chilean fjord system for recording climate changes of regional and global significance.  相似文献   

The role of mean ocean salinity in climate     

Paul D. Williams  Eric Guilyardi  Gurvan Madec  Silvio Gualdi  Enrico Scoccimarro 《Dynamics of Atmospheres and Oceans》2010,49(2-3):108-123

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New Soft Rock Pillar Strength Formula Derived Through Parametric FEA Using a Critical State Plasticity Model     

Giuseppe Rastiello  Francesco Federico  Silvio Screpanti 《Rock Mechanics and Rock Engineering》2015,48(5):2077-2091

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Generation of CO2-rich melts during basalt magma ascent and degassing   总被引：1，自引：0，他引：1  

Michel Pichavant  Ida Di Carlo  Silvio G. Rotolo  Bruno Scaillet  Alain Burgisser  Nolwenn Le Gall  Caroline Martel 《Contributions to Mineralogy and Petrology》2013,166(2):545-561

To test mechanisms of basaltic magma degassing, continuous decompressions of volatile-bearing (2.7–3.8 wt% H₂O, 600–1,300 ppm CO₂) Stromboli melts were performed from 250–200 to 50–25 MPa at 1,180–1,140 °C. Ascent rates were varied from 0.25 to ~1.5 m/s. Glasses after decompression show a wide range of textures, from totally bubble-free to bubble-rich, the latter with bubble number densities from 10⁴ to 10⁶ cm^?3, similar to Stromboli pumices. Vesicularities range from 0 to ~20 vol%. Final melt H₂O concentrations are homogeneous and always close to solubilities. In contrast, the rate of vesiculation controls the final melt CO₂ concentration. High vesicularity charges have glass CO₂ concentrations that follow theoretical equilibrium degassing paths, whereas glasses from low vesicularity charges show marked deviations from equilibrium, with CO₂ concentrations up to one order of magnitude higher than solubilities. FTIR profiles and maps reveal glass CO₂ concentration gradients near the gas–melt interface. Our results stress the importance of bubble nucleation and growth, and of volatile diffusivities, for basaltic melt degassing. Two characteristic distances, the gas interface distance (distance either between bubbles or to gas–melt interfaces) and the volatile diffusion distance, control the degassing process. Melts containing numerous and large bubbles have gas interface distances shorter than volatile diffusion distances, and degassing proceeds by equilibrium partitioning of CO₂ and H₂O between melt and gas bubbles. For melts where either bubble nucleation is inhibited or bubble growth is limited, gas interface distances are longer than volatile diffusion distances. Degassing proceeds by diffusive volatile transfer at the gas–melt interface and is kinetically limited by the diffusivities of volatiles in the melt. Our experiments show that CO₂-oversaturated melts can be generated as a result of magma decompression. They provide a new explanation for the occurrence of CO₂-rich natural basaltic glasses and open new perspectives for understanding explosive basaltic volcanism.  相似文献   

Implementation of an automatic calibration procedure for HYDROTEL based on prior OAT sensitivity and complementary identifiability analysis          下载免费PDF全文

Médard Bouda  Alain N. Rousseau  Silvio J. Gumiere  Patrick Gagnon  Brou Konan  Roger Moussa 《水文研究》2014,28(12):3947-3961

Efficiency of hydrological models mostly depends on the quality of the calibration performed prior to use. In this paper, an automatic calibration framework for the distributed hydrological model HYDROTEL is proposed. The calibration procedure was performed for three watersheds characterized with different hydroclimatological conditions: the Sassandra located in Ivory Coast, Africa, and the Montmorency and Beaurivage watersheds located in Quebec (Canada). Results of one‐a‐time (OAT) sensitivity analysis showed that the order of the most sensitive parameters differs for each watershed. Thus, the sensitivity depends on the hydroclimatic and physiographic characteristics of the watersheds. Co‐linearity indices showed that all model parameters were identifiable, that is, none of the studied parameters could be explained by a combination of the other parameters. Following these findings, an automatic calibration was run. Results indicated there was good agreement between simulated and measured streamflows at the outlet of each watershed; Nash–Sutcliffe efficiency (NSE) ranging between 0.77 and 0.92 and R² ranging from 0.87 to 0.97. When comparing NSE and R² values obtained using a process‐oriented, multiple‐objective, manual calibration strategy, a slight increase in model efficiency was reached with the automatic calibration procedure (4.15% for NSE and 2.95% for R²) improving predictions of peak flows for the Montmorency and Beaurivage watersheds (temperate climate conditions) and flows beyond the rainfall season in the Sassandra watershed. The proposed automatic calibration procedure introduced in this paper may be applied to other distributed hydrological model. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Sul sistema: Precipitazione-ghiaccio-deflusso     

Prof. Dr. Silvio Polli 《Pure and Applied Geophysics》1950,17(3-4):221-223

Riassunto Nel sistema precipitazione-deflusso si distinguono i 3 casi secondo che si passa dalla prima al secondo direttamente, o mediante la neve, oppure mediante il ghiaccio. Si considera in particolare questo ultimo caso mettendo in evidenza le proprietà inerziali dell'elemento intermedio. Facendo applicazione alle condizioni glacioclimatiche attuali si prevede per i prossimi anni un deflusso d'ablazione normale.

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Summary In the precipitation-runoff system they are distinguished the 3 cases according to it goes from the precipitation to the runoff directly or by the snow or by ice. Particular consideration is given to this last case. Then is brought in evidence the inertial property of the ice. Applying these considerations to the present conditions, it is forecast for the next years a nearly normal runoff.

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Riflessione ottica di una superficie marina in condizioni naturali     

Prof. Silvio Polli 《Pure and Applied Geophysics》1952,21(1):142-146

Riassunto Mediante cellula fotoelettrica e vetri-filtri selezionatori si determinarono le intensità delle radiazioni riflesse da una superficie acquea in condizioni naturali per ogni altezza solare fra 10^o e 80^o. Per angoli d'incidenza minori di 60^o circa la riflessione effettiva risultò 2–3 volte maggiore di quella teorica, per angoli più grandi risultò notevolmente minore. Massimi scostamenti dai valori teorici si ebbero per le radiazioni azzurre e violette.

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Summary By means of photocells and Schott's glass-filters the intensity of the reflected radiations from a surface of the sea have been determined for every sun-height between 10^o and 80^o. For the incident angles less than 60^o, the effective reflection resulted 2–3 times greater than the theoretic reflection, for greater angles it resulted remarkably inferior. The greatest differences between the determined and the theoretic values have been found for the blue and violet radiations.

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