Geotechnical Behavior and Physico-Chemical Changes of Lime-Treated and Cement-Treated Silty Soil     

Bouras  Fawzi  Al-Mukhtar  Muzahim  Tapsoba  Nouffou  Belayachi  Naima  Sabio  Serge  Beck  Kévin  Martin  Mylène 《Geotechnical and Geological Engineering》2022,40(4):2033-2049

Geotechnical and Geological Engineering - An investigation performed on the interactions of silty soil treated with cement or lime demonstrates the strong relationship between microstructural...  相似文献   

Peat Accumulation and Early Carboniferous Environments of the Kizel Coal Basin, the Urals, Russia     

Serge V. NAUGOLNYKH 《《地质学报》英文版》2022,96(3):1098-1112

The lithological and geochemical composition and conditions of formation of the coal-bearing deposits of the Kizel Coal Basin in the Perm region of the Urals (central Russia) are described using the two most representative sections, Gubakha–Stary Most and Krestovaya Mountain, based on a detailed “layer-by-layer” technique. Brief characteristics of the Lower Carboniferous paleosols from fossil paleosol (FPS-) profiles of the studied region are given. Special attention is paid to the parent vegetation of the coal-forming processes, based on an analysis of both plant macrofossils and palynoflora. The peat accumulation in conditions of permanent incoming of clastic material from the Paleo-Urals to the Kizel Basin was probably effective only in more or less stable environments, when the accumulated organic matter produced by plant mortmass was not dissolved by clastic particles. Thus, the conditions of coal-forming are reconstructed as a forest swamp, where the main dominants are represented by lycopodiopsids of the order Lepidodendrales, predominantly Lepidodendron veltheimii. These plants in particular were the source of the initial organic matter for the peat (and later coal) of the Kizel Coal Basin.  相似文献   

A Novel Technique for Measuring the Solar Radius from Eclipse Light Curves – Results for 2010, 2012, 2013, and 2015     

Philippe Lamy  Jean-Yves Prado  Olivier Floyd  Patrick Rocher  Guillaume Faury  Serge Koutchmy 《Solar physics》2015,290(10):2617-2648

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Spatial Variation of Sea-Spray Fluxes over a Mediterranean Coastal Zone Using a Sea-State Model   总被引：1，自引：1，他引：0  

Jacques Piazzola  Philippe Forget  Christine Lafon  Serge Despiau 《Boundary-Layer Meteorology》2009,132(1):167-183

We first deal with sea-spray flux estimates for short fetch conditions in coastal Mediterranean areas. To this end, a sea-state dependent model for the whitecap fraction was included in three different formulations for the sea-spray source function. A comparison with the sea-spray fluxes, calculated on the basis of aerosol size distributions measured at the island of Porquerolles located south off the French Riviera, evaluates the predictions of different whitecap dependant flux formulations. Then we deal with the spatial distribution of the whitecap fraction and the sea-spray fluxes in the study area. To achieve this, a whitecap dependant flux formulation was forced by a wave numerical model that was implemented in the study area. Experimental results on wave conditions have been used to adjust the model in the Mediterranean coastal area. Numerical simulations of wave and whitecap coverage have been carried out during typical regional wind events, and they show a nonhomogeneous distribution of the sea-surface production over the northern Mediterranean as a consequence of the spatial variation of the sea state. In particular, we note the occurrence of a narrow band of high sea-surface production following the northern coast and along the east part of the Gulf of Lions.  相似文献   

Study of the total lightning activity in a hailstorm   总被引：1，自引：0，他引：1  

Joan Montany  Serge Soula  Nicolau Pineda  Oscar van der Velde  Pere Clapers  Glria Sol  Joan Bech  D. Romero 《Atmospheric Research》2009,91(2-4):430-437

A thunderstorm that developed over northeastern Spain on 16 June 2006 is analyzed. This severe thunderstorm produced hailstones as large as 40 mm and had a lifetime of 3 h and 30 min. Radar cross-sections show strong vertical development with cloud echo tops reaching an altitude of 13 km. The specific characteristics of the lightning activity of this storm were: (i) a large amount (81%) of negative cloud-to-ground (−CG) flashes with very low peak currents (< 10 kA in absolute value), (ii) a very large proportion of intra-cloud (IC) flashes with an IC/CG ratio reaching about 400, (iii) a large number of “short” IC flashes (with only 1-VHF source according to SAFIR detection), (iv) a large increase of the −CG flash rate and of the CG proportion near the end of the storm. The rate of −CG flashes with a low peak current were observed to evolve similarly to the rates of IC flashes. Most of them have been assumed to be IC flashes misclassified by the Spanish Lightning Detection Network (SLDN). They have been filtered as it is usually done for misclassified +CG flashes. After this filtering, CG flash rates remained very low (< 1 min^− 1) with +CG flashes sometimes dominant. All the particular lightning activity characteristics similar to those observed in the Severe Thunderstorm Electrification and Precipitation Study (STEPS) campaigns support the hypothesis that this thunderstorm could have had an inverted-polarity or complex charge structure. The maximum IC flash rate (67 min^− 1) peaked 24 min before the presence of reflectivity higher than 60 dBZ. The IC activity abruptly decreased during the period when reflectivity was dramatically increasing. The time of maximum reflectivity observed by radar was consistent with the times of reported hail at the ground.  相似文献   

Adaptation of the optimal fingerprint method for climate change detection using a well-conditioned covariance matrix estimate   总被引：3，自引：3，他引：0  

Aurélien Ribes  Jean-Marc Azaïs  Serge Planton 《Climate Dynamics》2009,33(5):707-722

The “optimal fingerprint” method, usually used for detection and attribution studies, requires to know, or, in practice, to estimate the covariance matrix of the internal climate variability. In this work, a new adaptation of the “optimal fingerprints” method is presented. The main goal is to allow the use of a covariance matrix estimate based on an observation dataset in which the number of years used for covariance estimation is close to the number of observed time series. Our adaptation is based on the use of a regularized estimate of the covariance matrix, that is well-conditioned, and asymptotically more precise, in the sense of the mean square error. This method is shown to be more powerful than the basic “guess pattern fingerprint”, and than the classical use of a pseudo-inverted truncation of the empirical covariance matrix. The construction of the detection test is achieved by using a bootstrap technique particularly well-suited to estimate the internal climate variability in real world observations. In order to validate the efficiency of the detection algorithm with climate data, the methodology presented here is first applied with pseudo-observations derived from transient regional climate change scenarios covering the 1960–2099 period. It is then used to perform a formal detection study of climate change over France, analyzing homogenized observed temperature series from 1900 to 2006. In this case, the estimation of the covariance matrix is only based on a part of the observation dataset. This new approach allows the confirmation and extension of previous results regarding the detection of an anthropogenic climate change signal over the country.  相似文献   

Multi-tracer tests to evaluate the hydraulic setting of a complex aquifer system (Brévilles spring catchment, France)     

Pascal Goderniaux  Serge Brouyère  Alexis Gutierrez  Nicole Baran 《Hydrogeology Journal》2010,18(7):1729-1740

For good management of groundwater resources, and to comply with European and national regulations, a detailed understanding of an aquifer’s hydraulic setting is required. In order to better characterize a sandy aquifer that is affected by diffuse pollution (Brévilles spring catchment, Val d’Oise, France), and to quantify the transfer time in the saturated zone, a multi-tracer test involving a new technique, the ‘finite volume point dilution method’, has been performed in natural flow conditions. In November 2005, injections of four different tracers took place in four piezometers involving different locations and depths in the aquifer. Recovery of the tracers was observed at two different places near the aquifer outlet. A particularly long and unusual monitoring exercise (27 months) demonstrated the existence of several different velocities within the sandy layer, which seems to be linked to the decrease of hydraulic conductivity with depth. The new insight and parameter quantification brought by interpretation of these tests contribute to a better characterization of the saturated zone. The particularly long-term monitoring exercise also gives new information to understand and forecast the trend and persistence of groundwater contamination by pesticides in the catchment.  相似文献   

Organic matter in sediments of canyons and open slopes of the Portuguese,Catalan, Southern Adriatic and Cretan Sea margins     

Antonio Pusceddu  Silvia Bianchelli  Miquel Canals  Anna Sanchez-Vidal  Xavier Durrieu De Madron  Serge Heussner  Vasilios Lykousis  Henko de Stigter  Fabio Trincardi  Roberto Danovaro 《Deep Sea Research Part I: Oceanographic Research Papers》2010,57(3):441-457

We describe the quantitative and compositional (phytopigment, protein, carbohydrate and lipid) patterns of sedimentary organic matter along bathymetric gradients in seven submarine canyons and adjacent open slopes located at four European regions: one along the NE Atlantic and three along the Mediterranean continental margins. The investigated areas are distributed along a putative longitudinal gradient of decreasing primary production from the Portuguese (northeastern Atlantic Ocean), to the Catalan (western Mediterranean Sea), Southern Adriatic (central Mediterranean Sea) and Southern Cretan (eastern Mediterranean Sea) margins. Sediment concentrations of organic matter differed significantly between the Portuguese margin and the Mediterranean regions and also from one study area to the other within the Mediterranean Sea. Differences in quantity and composition of sediment organic matter between canyons and open slopes were limited and significant only in the eutrophic Portuguese margin, where the differences were as large as those observed between regions (i.e. at the mesoscale). These results suggest that the overall trophic status of deep margin sediments is controlled mostly by the primary productivity of the overlying waters rather than by the local topography. Moreover, we also report that the quantity and nutritional quality of sediment organic matter in canyons and adjacent open slopes do not show any consistent depth-related pattern. Only the Nazaré and Cascais canyons in the Portuguese margin, at depths deeper than 500 m, displayed a significant accumulation of labile organic matter. The results of our study underline the need of further investigations of deep margins through sampling strategies accounting for adequate temporal and spatial scales of variability.  相似文献   

Fast repeat-modelling of time-lapse seismograms     

Andreas Kirchner  Serge A. Shapiro 《Geophysical Prospecting》2001,49(5):557-569

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Detection of turbulent coherent motions in a forest canopy part II: Time-scales and conditional averages     

Serge Collineau  Yves Brunet 《Boundary-Layer Meteorology》1993,66(1-2):49-73

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