Evidence of slope instability in the Southwestern Adriatic Margin

International audienceThe Southwestern Adriatic Margin (SAM) shows evidence of widespread failure events that generated slide scars up to 10 km wide and extensive slide deposits with run out distances greater than 50 km. Chirp-sonar profiles, side-scan sonar mosaics, multibeam bathymetry and sediment cores document that the entire slope area underwent repeated failures along a stretch of 150 km and that mass-transport deposits, covering an area of 3320 km2, are highly variable ranging from blocky slides to turbidites, and lay on the lower slope and in the basin. The SAM slope between 300?700 m is impacted by southward bottom currents shaping sediment drifts (partly affected by failure) and areas of dominant erosion of the seafloor. When slide deposits occur in areas swept by bottom currents their fresh appearence and their location at seafloor may give the misleading impression of a very young age. Seismic-stratigraphic correlation of these deposits to the basin floor, however, allow a more reliable age estimate through sediment coring of the post-slide unit. Multiple buried failed masses overlap each other in the lower slope and below the basin floor; the most widespread of these mass-transport deposits occurred during the MIS 2-glacial interval on a combined area of 2670 km2. Displacements affecting Holocene deposits suggest recent failure events during or after the last phases of the last post-glacial eustatic rise. Differences in sediment accumulation rates at the base or within the sediment drifts and presence of downlap surfaces along the slope and further in the basin may provide one or multiple potential weak layers above which widespread collapses take place. Neotectonic activity and seismicity, together with the presence of a steep slope, represent additional elements conducive to sediment instability and failure along the SAM. Evidence of large areas still prone to failure provides elements of tsunamogenic hazard

An environment to share in-service training on the net: An action-research about charge in primary and middle school

The net was one of the determining factors in a training of a Group of 4 primary and middle school teachers (L. M. in Forni Di Sopra and C. D. F. in Villa Santina, P. C. in Tolmezzo and D. S. in Gemona, all places in the mountains of Friuli, in the Nord-East of Italy) in an action-research on the electric charge. It was developed through meetings with researchers in physics education and Exchange and sharing of experiences and projects on the net, in an environment designed for teaching activities and under the guidance of a project tutor. The environment allowed to establish different kinds of relations: between teachers, between them and researchers, between classes. It offered to teachers (two in middle school and two in primary school) a place for discussions during the design of paths to be presented to their classes, to structure and share the products of their training both during and after it, to reflect on their training path

Ab initio simulation of helium inside carbon nanotubes

In present work we consider the complex behaviour of quantum liquids like liquid He-4 inside carbon nanotubes. Interactions between helium atoms and carbon atoms of the short-length atomistic model and model with periodical boundary conditions of carbon nanotube were studied via ab initio quantum simulations. Effects of geometrical confinement of the tube on the He behaviour inside CNT (13,0) have been explored. Nanotubes with typical average diameter of 10 angstroms are under consideration

Ab-initio investigations of LuLiF4 compound under pressure

We have performed ab-initio calculations for the structural and mechanical properties of sheelite compound LuLiF4 under pressure. A good agreement with experimental results has been obtained

Ab initio simulation of effects of structural singularities in aerogel absorption potential

In the present work simulation of Van der Waals potential between helium atom and part of silica aerogel strand by means of ab initio methods was performed. Cell with alpha quartz structure was used as building block of aerogel strand, because it is the most stable structure at low temperature, and only the surface layer of aerogel has been considered. For modeling absorption potential field in plane, summation of potential from individual building blocks has been provided. Two dimensional Van der Waals energy field was calculated for different geometries of aerogel strands. A rather deep potential well has been found in the corner formed due to aerogel strand crossing

Ab initio investigation of phonon spectra in GdLiF4 compound under hydrostatic pressure

Employing density functional theory (DFT) within the generalized gradient approximation, the GdLiF4 structure has been studied for a pressure range from 0 to 12 GPa. The influence of pressure on the lattice vibrational spectrum of the scheelite phase (I41/a, Z = 4) has been evaluated by means the "direct" approach, i.e., using force constants calculated from atomic displacements. As a result the Raman and infrared modes have been identified and their dependencies on pressure have been investigated and compared with available experimental data. It has been found that instability of the crystal structure appears at pressures above 6 GPa. © 2014 Pleiades Publishing, Ltd

Density functional theory calculations on azobenzene derivatives: a comparative study of functional group effect

© 2014, Springer-Verlag Berlin Heidelberg. Density functional theory (DFT) calculations have been used to investigate the structural properties, dipole moments, polarizabilities, Gibbs energies, hardness, electronegativity, HOMO/LUMO energies, and chemical potentials of trans and cis configurations of eight para-substituted azobenzene derivatives. All properties have been obtained using the B3LYP functional and 6-31++G(d,p) basis set. The planar structures have been obtained for all optimized trans configurations. The energy difference between trans and cis configurations for considered derivatives was found to be between 64.2–73.1 kJ/mole. It has been obtained that the p-aminodiazo-benzene (ADAB) has the difference in the dipole moments between trans and cis forms higher than for trans and cis azobenzene

Pressure-induced ferroelastic phase transition in LuLiF<inf>4</inf> compound

© 2015 Taylor & Francis. The behavior of LuLiF4 sheelite (I41/a, Z = 4) under hydrostatic pressure was investigated by means of first principles calculations. The ferroelastic phase transition from the tetragonal structure of LuLiF4 to the fergusonite structure (C12/c1, Z = 4) has been found at 10.5 GPa. It has been determined that this is the second-order phase transition

Ab-initio investigation of GdLiF4 structure under pressure

This work is devoted to the ab-initio studies of rare-earth double fluoride GdLiF4 under external hydrostatic pressure. Structural and mechanical properties were considered by means of Vienna Ab-initio Simulation Program (VASP). A good agreement of lattice parameters and bulk modulus with experimental data has been obtained. The seven independent elastic constants of I41/a GdLiF4 structure were calculated from stress-strain method. The provideab-initio studies has revealed the instability of GdLiF 4 crystal structure above 10 GPa in accordance with available experimental findings