L'evolution du cortege des mineraux argileux dans la sedimentation marine neogene du bassin occidental du Guadalquivir (Espagne du s.o.)

La depresión neógena de sedimentación marina del Bajo Guadalquivir resulta del hundimiento del zócalo durante el Mioceno final. En cuanto se asienta dicha depresión, está ocupada en su mayor parte por el manto de corrimiento submarino de Carmona, que la parte en tres "subestructuras": una depresión S. en el área subbética, una cúpula central al S y al SE de Sevilla, un surco N en el borde del Paleozoicode la Meseta ibérica.En las dos primeras, la sedimentación arcillosa se caracteriza por la abundancia de la montmorillonita. En la última, los minerales arcillosos predominantes siguen una evolución cíclica vertical : Montmorillonita - Illita - Kaolinita + Chlorita - Illita - Montmorillonita, interpretada mediante el acarreo de dos clases de materiales detríticos finos: - procedentes directamente de los continentes limítrofes de clima caluroso y de estaciones contrastadas, en cuanto a la abundancia de la Montmorillonita; - procedentes del mar, desde regiones más o menos próximas, de clima caluroso más húmedo, en cuanto a los sedimentos,entre los cuales predominan Iillita, Kaolinita y Chlorita.Por otra parte, los valores elevados de dichos minerales muestran que a fines del Mioceno superior II y a principios del Plioceno, el surco norte bético se abre a las influencias marinas, quedándose fuera del control continental de sedimentación durante ese corto período

L'evolution du cortege des mineraux argileux dans la sedimentation marine neogene du bassin occidental du Guadalquivir (Espagne du s.o.)

La depresión neógena de sedimentación marina del Bajo Guadalquivir resulta del hundimiento del zócalo durante el Mioceno final. En cuanto se asienta dicha depresión, está ocupada en su mayor parte por el manto de corrimiento submarino de Carmona, que la parte en tres "subestructuras": una depresión S. en el área subbética, una cúpula central al S y al SE de Sevilla, un surco N en el borde del Paleozoicode la Meseta ibérica.En las dos primeras, la sedimentación arcillosa se caracteriza por la abundancia de la montmorillonita. En la última, los minerales arcillosos predominantes siguen una evolución cíclica vertical : Montmorillonita - Illita - Kaolinita + Chlorita - Illita - Montmorillonita, interpretada mediante el acarreo de dos clases de materiales detríticos finos: - procedentes directamente de los continentes limítrofes de clima caluroso y de estaciones contrastadas, en cuanto a la abundancia de la Montmorillonita; - procedentes del mar, desde regiones más o menos próximas, de clima caluroso más húmedo, en cuanto a los sedimentos,entre los cuales predominan Iillita, Kaolinita y Chlorita.Por otra parte, los valores elevados de dichos minerales muestran que a fines del Mioceno superior II y a principios del Plioceno, el surco norte bético se abre a las influencias marinas, quedándose fuera del control continental de sedimentación durante ese corto período

Loss of strength in Ni3Al at elevated temperatures

Stress decrease above the stress peak temperature (750 K) is studied in h123i single crystals of Ni3(Al, 3 at.% Hf ). Two thermally activated deformation mechanisms are evidenced on the basis of stress relaxation and strain rate change experiments. From 500 to 1070 K, the continuity of the activation volume/temperature curves reveals a single mechanism of activation enthalpy 3.8 eV/atom and volume 90 b3 at 810K with an athermal stress of 330 MPa. Over the very same temperature interval, impurity or solute diffusion towards dislocation cores is evidenced through serrated yielding, peculiar shapes of stress–strain curves while changing the rate of straining and stress relaxation experiments. This complicates the identification of the deformation mechanism, which is likely connected with cube glide. From 1070 to 1270 K, the high-temperature mechanism has an activation enthalpy and volume of 4.8 eV/atom and 20 b3, respectively, at 1250 K

PERFORMANCE OF TIMBER BOARD MODELS FOR PREDICTION OF LOCAL BENDING STIFFNESS AND STRENGTH – WITH APPLICATION ON DOUGLAS FIR SAWN TIMBER

Efficient utilization of structural timber requires accurate methods for machine strength grading. One of the most accurate methods presented this far is based on data of local fiber orientation on board surfaces, obtained from laser scanning. In this paper, two potential improvements of this method are examined. The first one consists of replacing a model based on simple integration over cross sections of boards for calculation of local bending stiffness by a 3D solid finite element (FE) model from which local bending stiffness is derived. The second improvement concerns replacement of a simple model for the fiber orientation in the interior of board by a more advanced one taking location of pith and growth direction of knots into account. Application of the alternative models on a sample of more than 200 Douglas fir boards, size 40 mm X 100 mm X 3000 mm, cut from large logs, show that each of the evaluated model improvements contributes to improved grading accuracy. When local bending stiffness is calculated utilizing the herein suggested FE model in combination with the improved model of fiber orientation in the interior of boards, a coefficient of determination to bending strength as high as 0.76 is obtained. For comparison, a coefficient of determination of 0.71 is obtain using the simpler original models

Correspondences, an exhibition of installations : Peter Burgess et al

Correspondences, an exhibition of installations : Peter Burgess et al Catalogue of Exhibition held at the Tasmanian School of Art, University of Tasmania 4 July-20 July, 1984 Works by Peter Burgess, Peter Callas, Adrian Hall, Maryrose Sinn, Gregory Smith, Neil Stevenson, Alain Viguier, John Youn

Microstructural Characterization of Graphite Spheroids in Ductile Iron

The present work brings new insights by transmission electron microscopy allowing disregarding or supporting some of the models proposed for spheroidal growth of graphite in cast irons. Nodules consist of sectors made of graphite plates elongated along a hai direction and stack on each other with their c axis aligned with the radial direction. These plates are the elementary units for spheroidal growth and a calculation supports the idea that new units continuously nucleate at the ledge between sectors

Early warning of critical transitions in biodiversity from compositional disorder

Global environmental change presents a clear need for improved leading indicators of critical transitions, especially those that can be generated from compositional data and that work in empirical cases. Ecological theory of community dynamics under environmental forcing predicts an early replacement of slowly replicating and weakly competitive “canary” species by slowly replicating but strongly competitive “keystone” species. Further forcing leads to the eventual collapse of the keystone species as they are replaced by weakly competitive but fast‐replicating “weedy” species in a critical transition to a significantly different state. We identify a diagnostic signal of these changes in the coefficients of a correlation between compositional disorder and biodiversity. Compositional disorder measures unpredictability in the composition of a community, while biodiversity measures the amount of species in the community. In a stochastic simulation, sequential correlations over time switch from positive to negative as keystones prevail over canaries, and back to positive with domination of weedy species. The model finds support in empirical tests on multi‐decadal time series of fossil diatom and chironomid communities from lakes in China. The characteristic switch from positive to negative correlation coefficients occurs for both communities up to three decades preceding a critical transition to a sustained alternate state. This signal is robust to unequal time increments that beset the identification of early‐warning signals from other metrics

Testing adaptive hypotheses of alloparenting in Agta foragers.

Human children are frequently cared for by non-parental caregivers (alloparents), yet few studies have conducted systematic alternative hypothesis tests of why alloparents help. Here we explore whether predictions from kin selection, reciprocity, learning-to-mother and costly signalling hypotheses explain non-parental childcare among Agta hunter-gatherers from the Philippines. To test these hypotheses, we used high-resolution proximity data from 1,701 child-alloparent dyads. Our results indicated that reciprocity and relatedness were positively associated with the number of interactions with a child (our proxy for childcare). Need appeared more influential in close kin, suggesting indirect benefits, while reciprocity proved to be a stronger influence in non-kin, pointing to direct benefits. However, despite shared genes, close and distant kin interactions were also contingent on reciprocity. Compared with other apes, humans are unique in rapidly producing energetically demanding offspring. Our results suggest that the support that mothers require is met through support based on kinship and reciprocity

Cryptanalysis of MORUS

Item does not contain fulltextAdvances in Cryptology - ASIACRYPT 2018 - 24th International Conference on the Theory and Application of Cryptology and Information Security, Brisbane, QLD, Australia, December 2-