Search results for "deformation"
showing 10 items of 515 documents
Deformation of sulfur hexafluoride and floppiness of trifluoromethyl sulfur pentafluoride
2006
International audience; With recent advances in space exploration and atmospheric chemistry there is an increased need for more spectroscopic tools to allow the of study complex species. One such tool is the theory of frame transformation of coupled rotor systems. In this article, the theory of frame transformation along with the concept of rotational energy surface is used to study the symmetry that occurs in trifluoromethyl sulfur pentafluoride due to the internal rotation of the CF3 radical and, more generally, to the extent of floppiness of SF5CF3. Other lower symmetries when a CF4 molecule is stuck on the various symmetry axes of an SF6 molecule are also discussed.
Role of Diffusion in Superplasticity and Brittleness of Fine-Grained Binary Eutectics
2005
Mechanical properties of interphase boundaries (IB), stability of defects and microstructure in heavily deformed binary eutectics (Al-Sn, Zn-Sn, Pb-Sn, Cd-Sn, Bi-Sn) have been investigated at room temperature. Experiments were carried out on atomically clean surfaces of alloys and on bimetallic joints with clean interface. It has been shown that after severe deformation the phases are strengthened and relaxation processes occur mainly on the boundaries in all eutectics. For superplastic eutectics with low interphase boundary energy the intensive development of the diffusion – controlled processes of self- healing, sintering, segregation and enveloping were observed. These diffusion processe…
A 3D Cohesive interface for the delamination analysis of a stiff film on a soft elastic substrate and the wrinkling/buckling deformation modes
2018
The paper proposes a finite element systematic study of a mechanical system composed by a soft elastic substrate, subjected to a uniform state of compression, covered by a stiff thin film. This kind of problem is rather common for coating systems where layered materials with severe mismatch of elastic and thermal properties are largely employed. The specific mechanical problem stands on the concomitant competition between elastic wrinkling surface deformation and the nonlinear delamination that can develop at the interface between the thin film and the substrate. Both mechanical phenomena have their source in the nonlinear elastic buckling of the thin stiff film, which can be viewed as a th…
Quantum Simulations of One-Dimensional Nanostructures under Arbitrary Deformations
2016
A powerful technique is introduced for simulating mechanical and electromechanical properties of one-dimensional nanostructures under arbitrary combinations of bending, twisting, and stretching. The technique is based on a novel control of periodic symmetry, which eliminates artifacts due to deformation constraints and quantum finite-size effects, and allows transparent electronic structure analysis. Via density-functional tight-binding implementation, the technique demonstrates its utility by predicting novel electromechanical properties in carbon nanotubes and abrupt behavior in the structural yielding of Au7 and MoS nanowires. The technique drives simulations markedly closer to the reali…
Synsedimentary-tectonic, soft-sediment deformation and volcanism in the rifted Tethyan margin from the Upper Triassic–Middle Jurassic deep-water carb…
2014
Abstract The Pizzo Lupo section (Sicanian Mts, central Sicily) is an Upper Triassic–Lower Jurassic condensed deep-water succession, where the relationships among synsedimentary tectonic, soft-sediment deformations, volcanism and lithological changes reflect the evolution of a rift-basin. The morphostructural setting of the studied basin appears as a gently dipping slope where a fault-delimited area (graben to halfgraben) was developed. The instability of the sea floor, related to the seismic shocks, was the cause of the gravity-driven deformational sedimentary structures (slumping, breccia channelized bodies). The partly stratified basaltic rocks, with disorganized and chaotic stratificatio…
Preliminary results of a geomorphological and DInSAR characterization of a recently identified Deep-Seated Gravitational Slope Deformation in Sicily …
2019
The study is part of a larger project that involves the analysis of recently identified Deep-Seated Gravitational Slope Deformation (DSGSD) in Sicily which have been sub-divided according to the geological framework in light of the new geological data about the regional setting. Here are presented the first results of a multidisciplinary study of a DSGSD recently identify in Mount San Calogero area (Northern Sicily). The study was performed by means of different approaches including conventional methods (field surveys) and the Differential Interferometry Synthetic Aperture Radar (DInSAR) technique. The geological and geomorphological analyses were carried out to investigate slopes dynamic, …
Late Cenozoic brittle deformation in the Southern Patagonian Andes: Record of plate coupling/decoupling during variable subduction?
2018
The Andes of southern Patagonia experienced a Miocene shift towards faster and higher angle subduction followed by the approach and collision of the Chile oceanic ridge. We present a kinematic study characterizing palaeostress fields computed from brittle tectonics to better constrain upper crustal deformation during this complex scenario. Although previous studies already suggested variable kinematics, it is striking that in a long-lasting subduction environment, the computed palaeostress tensors are mostly strike-slip (55%), while 35% are extensional, and only 10% compressive which are concentrated along a main frontal thrust. Cross-cutting relationships and synsedimentary deformation ind…
Active faults and inferred seismic sources in the San Vito lo Capo peninsula, Northwestern Sicily, Italy.
2006
Two independent active faults, capable of generating medium-sized earthquakes in the San Vito lo Capo peninsula, northwestern Sicily (Italy) have been identified as a result of detailed field studies. In western Sicily, instrumental seismicity is low; in fact, except for the 1968 Belice earthquake (Ms = 5.4), historical records indicate that this area is relatively quiescent. Most of the seismicity is in the offshore sector of the Sicilian Maghrebian Chain, which is characterized by several medium- to low-magnitude events. The main shock of the 2002 Palermo seismic sequence (Mw = 5.9) represents the largest earthquake felt in the area in recent years. The deformation pattern characterizing …
In-beam spectroscopic study of Cf244
2018
The ground-state rotational band of the neutron-deficient californium (Z = 98) isotope 244Cf was identified for the first time and measured up to a tentative spin and parity of I I-pi = 20(+). The observation of the rotational band indicates that the nucleus is deformed. The kinematic and dynamic moments of inertia were deduced from the measured gamma-ray transition energies. The behavior of the dynamic moment of inertia revealed an up-bend due to a possible alignment of coupled nucleons in high-j orbitals starting at a rotational frequency of about (h) over bar (omega) = 0.20 MeV. The results were compared with the systematic behavior of the even-even N = 146 isotones as well as with avail…
Experiments on Longitudinal and Transverse Bedload Transport in Sine-Generated Meandering Channels
2021
Bedload grains in consecutive meandering bends either move longitudinally or across the channel centerline. This study traces and quantifies the grains’ movement in two laboratorial sine-generated channels, i.e., one with deflection angle θ0 = 30° and the other 110°. The grains originally paved along the channels are uniform in size with D = 1 mm and are dyed in various colors, according to their initial location. The experiments recorded the changes in the flow patterns, bed deformation, and the gain-loss distribution of the colored grains in the pool-bar complexes. We observed the formation of two types of erosion zones during the process of the bed deformation, i.e., Zone 1 in the foresi…