Rapid Stabilization of Sands with Deep Mixing Method Using Polyester

Rapid stabilization of weak soils is one of the important and current topics in geotechnical researches such as military application and stabilization of landslides. Deep mixing is an improvement method applied in the form of creating mixed columns which involves in-situ mixing of soil and lime or Portland cement with special equipment. The aim of this study was to evaluate the feasibility of utilizing polymers as a binder for rapid stabilization of sandy soils with deep mixing method. For this purpose, a series of unconfined compression tests were conducted on three dierent sandy soils improved with polyester. In the experiments, polyester was used at three dierent ratios of 10%, 20% and 30% and samples cured for 3 hour, 1, 3, 7 and 28 days. The laboratory test results of 3 hours samples showed that soils mixed with adequate polyester could reach a similar strength range of 28 days cured soils improved with cement or lime which was reported in the literature. The unconfined compressive strength increased with the increasing polyester ratio, effective diameter, and relative density and curing period, whereas, the changes on unconfined compressive strength were insignificant with the increase of freeze-thaw cycles. The overall evaluation of results has revealed that polyester is a good promise and a potential candidate for rapid deep mixing applications

Forward modelling of brightness variations in Sun-like stars -- II. Light curves and variability

The amplitude and morphology of light curves of solar-like stars change substantially with increasing rotation rate: brightness variations get amplified and become more regular, which has so far not been explained. We develop a modelling approach for calculating brightness variations of stars with various rotation rates and use it to explain observed trends in stellar photometric variability. We combine numerical simulations of magnetic Flux Emergence And Transport (FEAT) with a model for stellar brightness variability to calculate synthetic light curves of stars as observed by the Kepler telescope. We compute the distribution of magnetic flux on the stellar surface for various rotation rates and degrees of active-region nesting (i.e., the tendency of active regions to emerge in the vicinity of recently emerged ones). Using the resulting maps of the magnetic flux, we compute the rotational variability of our simulated stellar light curves as a function of rotation rate and nesting of magnetic features and compare our calculations to Kepler observations. We show that both rotation rate and degree of nesting have a strong impact on the amplitude and morphology of stellar light curves. In order to explain the variability of the bulk of \K{} targets with known rotation rates, we need to increase the degree of nesting to values much larger than on the Sun. The suggested increase of nesting with the rotation rate can provide clues to the flux emergence process for high levels of stellar activity.Comment: 10 pages, 15 figure

Polar branches of stellar activity waves: dynamo models and observations

[Abridged abstract:] Stellar activity data provide evidence of activity wave branches propagating polewards rather than equatorwards (the solar case). Stellar dynamo theory allows polewards propagating dynamo waves for certain governing parameters. We try to unite observations and theory, restricting our investigation to the simplest mean-field dynamo models. We suggest a crude preliminary systematization of the reported cases of polar activity branches. Then we present results of dynamo model simulations which contain magnetic structures with polar dynamo waves, and identify the models which look most promising for explaining the latitudinal distribution of spots in dwarf stars. Those models require specific features of stellar rotation laws, and so observations of polar activity branches may constrain internal stellar rotation. Specifically, we find it unlikely that a pronounced poleward branch can be associated with a solar-like internal rotation profile, while it can be more readily reproduced in the case of a cylindrical rotation law appropriate for fast rotators. We stress the case of the subgiant component of the active close binary HR 1099 which, being best investigated, presents the most severe problems for a dynamo interpretation. Our best model requires dynamo action in two layers separated in radius. Observations of polar activity branches provide valuable information for understanding stellar activity mechanisms and internal rotation, and thus deserve intensive observational and theoretical investigation. Current stellar dynamo theory seems sufficiently robust to accommodate the phenomenology.Comment: 13 pages, 10 figures, 4 tables, accepted by Astronomy and Astrophysic

CETOBaC – Centre d’études turques, ottomanes, balkaniques et centrasiatiques

Constant Hamès, chargé de recherche au CNRSAlexandre Popovic, directeur de recherche émérite au CNRS Histoire moderne et contemporaine des musulmans balkaniques Nous avons pu terminer au cours de cette année l’analyse détaillée du très riche ouvrage de l’historien et turcologue serbe Glisa Elezovic (1879-1960), Derviski redovi muslimanski. Tekije u Skoplju (Les ordres de derviches musulmans. Les tekke de Skoplje), paru à Skoplje même en 1925 (d’abord en feuilleton dans deux périodiques locaux..

CETOBaC – Centre d’études turques, ottomanes, balkaniques et centrasiatiques

Constant Hamès, chargé de recherche au CNRSAlexandre Popovic, directeur de recherche émérite au CNRS Histoire moderne et contemporaine des musulmans balkaniques Nous avons pu terminer au cours de cette année l’analyse détaillée du très riche ouvrage de l’historien et turcologue serbe Glisa Elezovic (1879-1960), Derviski redovi muslimanski. Tekije u Skoplju (Les ordres de derviches musulmans. Les tekke de Skoplje), paru à Skoplje même en 1925 (d’abord en feuilleton dans deux périodiques locaux..

European Vegetation Archive (EVA): An integrated database of European vegetation plots

© 2016 International Association for Vegetation Science. The European Vegetation Archive (EVA) is a centralized database of European vegetation plots developed by the IAVS Working Group European Vegetation Survey. It has been in development since 2012 and first made available for use in research projects in 2014. It stores copies of national and regional vegetation- plot databases on a single software platform. Data storage in EVA does not affect on-going independent development of the contributing databases, which remain the property of the data contributors. EVA uses a prototype of the database management software TURBOVEG 3 developed for joint management of multiple databases that use different species lists. This is facilitated by the SynBioSys Taxon Database, a system of taxon names and concepts used in the individual European databases and their corresponding names on a unified list of European flora. TURBOVEG 3 also includes procedures for handling data requests, selections and provisions according to the approved EVA Data Property and Governance Rules. By 30 June 2015, 61 databases from all European regions have joined EVA, contributing in total 1 027 376 vegetation plots, 82% of them with geographic coordinates, from 57 countries. EVA provides a unique data source for large-scale analyses of European vegetation diversity both for fundamental research and nature conservation applications. Updated information on EVA is available online at http://euroveg.org/eva-database