Manioc : Portail | resultats 1 - 20 pour la recherche: glide systems

Reports from committees : eighteen volumes. Sugar and coffee planting. Session 18 november 1847 - 5 september 1848, Part. 4
Auteur(s) : Grande Bretagne. House of commons. Library
Année de publication :

| Plus

Éléments de fortification contenant la construction raisonnée des ouvrages de la fortification. Les systèmes des ingénieurs les plus célèbres, la fortification irrégulière, le tracé des redoutes, forts de campagnes etc

| Plus

Observations and advices for the improvement of the manufacture of muscovado sugar and rum. Part 2
Auteur(s) : Higgins, Bryan (1737?-1820)
Année de publication :

| Plus

Speeches of Henry Lord Brougham, upon questions relating to Publics Rights, Duties, and Interests
Auteur(s) : Brougham, Henry (1778-1868)
Année de publication :

| Plus

Sediment distribution and evolution of sedimentary processes in a small sandy turbidite system (Golo system, Mediterranean Sea): implications for various geometries based on core framework
Auteur(s) : Gervais, A Mulder, T Savoye, Bruno Gonthier, E

Éditeur(s) : Springer
Résumé : The Golo Margin in eastern Corsica is dissected by four canyons and two gullies which fed turbidite systems. Study of the dispersal of surficial sediments and flow dynamic in the Golo system is based on Kullenberg and interface cores interpreted in relation to a previously published seismic dataset. Cores were described in detail and interpreted within a sedimentary and stratigraphic framework. During the last 42,000 years, gravity processes which occurred in the large systems with a canyon source were mainly slide-induced, differentiated turbulent surges and hyperpycnal flows. Processes occurring in the small system with a gully source are mainly hyperconcentrated and concentrated flows. Deposits from the Corsican Margin can intercalate with products of processes triggered on the Pianosa Ridge located in the eastern part of the basin. During relative sea-level lowstands or during periods of rapid or high-amplitude sea-level fall, only large canyons (South and North Golo) are supplied by carbonate-rich hyperconcentrated and concentrated flows which are channelled in incised valleys on the shelf. During periods of slow or low-amplitude sea-level fall and during sea-level rise, sediments are trapped on a shelf delta and intensely winnowed by shelf hydrodynamic processes. Sand-rich hyperconcentrated and concentrated flows occur. All the systems fed by a canyon are active simultaneously. Gullies form and are active only during periods of sea-level rise. During relative highstands of sea level (Holocene), all the system is draped by hemipelagic sediments. Relative sea-level changes and canyon location relative to river mouths have a strong influence on the nature of sediment input, and the initiation and type of gravity flows which, in turn, control morphology and geometry.
Geo-Marine Letters (0276-0460) (Springer), 2006-12 , Vol. 26 , N. 6 , P. 373-395

Droits : 2006 Springer
http://archimer.ifremer.fr/doc/2006/publication-3594.pdf
DOI:10.1007/s00367-006-0045-z
http://archimer.ifremer.fr/doc/00000/3594/

| Plus

Les nouvelles conquêtes de la science : les voies ferrées dans les deux mondes
Auteur(s) : Figuier, Louis (1819-1894)
Auteurs secondaires : Ferat, Jules (1819-1) Gilbert, A. Broux, P. (18..-18..)
Année de publication :

| Plus

Flora brasiliensis : enumeratio plantarum in Brasilia hactenus detectarum quas suis aliorumque botanicorum studiis descriptas et methodo naturali digestas partim icone illustratas. Volumen XIV, Pars II
Auteur(s) : Hooker, Joseph Dalton (1817-1911) Eichler, August Wilhelm (1837-1887) Engler, Adolf (1844-1930) Baker, John Gilbert (1834-1920) Rohrbach, Paul Schmidt, Johann Anton (1823-1905)
Auteurs secondaires : Martius, Karl Friedrich Philipp von (1794-1868)
Année de publication :

| Plus

Flora brasiliensis : enumeratio plantarum in Brasilia hactenus detectarum quas suis aliorumque botanicorum studiis descriptas et methodo naturali digestas partim icone illustratas. Volumen XI, Pars II, Euphorbiaceae
Auteur(s) : Müller, Joannes
Auteurs secondaires : Martius, Karl Friedrich Philipp von (1794-1868) Eichler, August Wilhelm (1837-1887)
Année de publication :

| Plus

Predicted glide systems and crystal preferred orientations of polycrystalline silicate Mg-Perovskite at high pressure: Implications for the seismic anisotropy in the lower mantle
Auteur(s) : Mainprice, Dave Tommasi, Andrea Ferre, D. Carrez, P. Cordier, P.
Auteurs secondaires : Géosciences Montpellier ; Université des Antilles et de la Guyane (UAG) - Institut national des sciences de l'Univers (INSU - CNRS) - Université de Montpellier (UM) - Centre National de la Recherche Scientifique (CNRS) Laboratoire de structures et propriétés de l'état solide (LSPES) ; Université de Lille, Sciences et Technologies - Centre National de la Recherche Scientifique (CNRS)

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We use first first-principle methods and the Peierls-Nabarro model to evaluate the resistance to glide, characterized by the Peierls stress, of glide systems for end-member MgSiO3 Perovskite at mantle pressures. [010](100) is the easiest glide system in Mg-Perovskite at all pressures. Peierls stresses increase systematically with pressure for all systems except [001](010), indicating the importance of lattice friction at lower mantle pressures. The ratio of the maximum Peierls stress for each system relative to the [010](100) value defines their critical resolved shear stress (CRSS). These CRSS are used in a visco-plastic self-consistent homogenization model to predict the evolution of crystal preferred orientations (CPO) during deformation of polycrystalline Mg-Perovskite. In axial compression, [100] tends to align with the compression direction, in agreement with in situ observations in axial compression experiments. In simple shear, [010] concentrates near the shear direction and (100), although more dispersed, tends to align near the shear plane, consistent with the dominant activity of the easier [010](100) system. The calculated seismic anisotropy for a 100% Mg-Perovskite aggregate using the CPO in simple shear and the elastic constants Of MgSiO3 perovskite at lower mantle pressures and temperatures is weak (>3% for P-waves with and >2% for S-waves) and decreases with increasing temperature and pressure. P-waves show the fastest propagation parallel to the lineation and S-waves fast polarization is in the foliation at 38 GPa and normal to the lineation at 88 GPa. This weak anisotropy is consistent with global seismological observations of a nearly isotropic lower mantle. There are however two regions where strain-induced Mg-Perovskite CPO could contribute to anisotropy; a) low temperature regions in the uppermost lower mantle, where the predicted S-wave polarization anisotropy may attain 1.6% with a fast polarization parallel to the foliation, b) in high high-temperature domains in the D '' layer, where Mg-Perovskite may be the major stable phase, leading to polarization of fast S-waves normal to the lineation for propagation directions at high angle to the lineation and an apparent isotropy for all other propagation directions.
ISSN: 0012-821X

hal-00411460
https://hal.archives-ouvertes.fr/hal-00411460
DOI : 10.1016/j.epsl.2008.03.058

| Plus