scholarly journals Reactivation of a Huge, Deep-Seated, Ancient Landslide: Formation Mechanism, Deformation Characteristics, and Stability

Water ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1960
Author(s):  
Shilin Luo ◽  
Xiaoguang Jin ◽  
Da Huang ◽  
Xibin Kuang ◽  
Yixiang Song ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Formation Mechanism ◽  
Slip Surface ◽  
Surface Displacement ◽  
Periodic Variation ◽  
Formation Mechanisms ◽  
Deformation Characteristics ◽  
Reservoir Water ◽  
Fast Movement ◽  
Major Factors

In this study, an investigation on the formation mechanisms, deformation characteristics, and stability of the Outang landslide, composed by three independent blocks (O1, O2, and O3), is performed by integrating site surveys, multi-technique monitoring data, and numerical simulation. The results show that the formation mechanism for blocks O1 and O3 is slide-bulking, and is planar slide for block O2. These three blocks slide along the incompetent layers (ILs): IL1 is the slip surface of block O1 and O2, and IL3 is the slip surface of block O3. Furthermore, the west local fast movement zone might evolve into deep failure. The slope surface movement is step-like, characterized by the alternation of rapid displacement followed by imperceptible displacement over each hydrological year. The surface displacement velocities increased upslope. Based on the numerical simulation, both precipitation and reservoir water are believed as the major factors driving the slope behaviors, and the slope stability would be decreased gradually under the effect of the periodic variation of water level and seasonal precipitation infiltration. As a result of this study, some countermeasures of landslide and long-term monitoring are recommended.

scholarly journals Mechanisms of Ohmic Contact Formation of Ti/Al-Based Metal Stacks on p-Doped 4H‑SiC

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 50
Author(s):  
Matthias Kocher ◽  
Mathias Rommel ◽  
Pawel Michalowski ◽  
Tobias Erlbacher
Keyword(s):  
Numerical Simulation ◽  
Formation Mechanism ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Formation Mechanisms ◽  
Contact Formation ◽  
Wide Range ◽  
Electron Devices ◽  
Ohmic Contact Formation

Ohmic contacts on p-doped 4H-SiC are essential for the fabrication of a wide range of power electron devices. Despite the fact that Ti/Al based ohmic contacts are routinely used for ohmic contacts on p-doped 4H-SiC, the underlying contact formation mechanisms are still not fully understood. TLM structures were fabricated, measured and analyzed to get a better understanding of the formation mechanism. SIMS analyses at the Ti3SiC2-SiC interface have shown a significant increase of the surface near Al concentration. By using numerical simulation it is shown that this additional surface near Al concentration is essential for the ohmic contact formation.

Numerical simulation study on formation mechanism of void distributions of proppant particles

2020 ◽  
Author(s):  
Shengyong Hu ◽  
Shuwen Guan ◽  
Guorui Feng ◽  
Xitu Zhang ◽  
Yunbo Chen ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Formation Mechanism ◽  
Simulation Study

scholarly journals Particle concentration and flux dynamics in the atmospheric boundary layer as the indicator of formation mechanism

2011 ◽  
Vol 11 (12) ◽  
pp. 5591-5601 ◽  
Author(s):  
J. Lauros ◽  
A. Sogachev ◽  
S. Smolander ◽  
H. Vuollekoski ◽  
S.-L. Sihto ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Formation Mechanism ◽  
Turbulent Transport ◽  
Particle Formation ◽  
Formation Mechanisms ◽  
Forest Site ◽  
Aerosol Formation ◽  
Flux Dynamics ◽  
Layer Deposition

Abstract. We carried out column model simulations to study particle fluxes and deposition and to evaluate different particle formation mechanisms at a boreal forest site in Finland. We show that kinetic nucleation of sulphuric acid cannot be responsible for new particle formation alone as the simulated vertical profile of particle number concentration does not correspond to observations. Instead organic induced nucleation leads to good agreement confirming the relevance of the aerosol formation mechanism including organic compounds emitted by the biosphere. The simulation of aerosol concentration within the atmospheric boundary layer during nucleation event days shows a highly dynamical picture, where particle formation is coupled with chemistry and turbulent transport. We have demonstrated the suitability of our turbulent mixing scheme in reproducing the most important characteristics of particle dynamics within the boundary layer. Deposition and particle flux simulations show that deposition affects noticeably only the smallest particles in the lowest part of the atmospheric boundary layer.

Physical experiment investigation on progressive deformation of shear slip surface of the soil slope

2021 ◽  
Author(s):  
Qiang Xie ◽  
Yuxin Ban ◽  
Zhihui Wu ◽  
Xiang Fu
Keyword(s):  
High Frequency ◽  
Surface Deformation ◽  
Slip Surface ◽  
Progressive Failure ◽  
Surface Displacement ◽  
Soil Slope ◽  
Progressive Deformation ◽  
Shear Surface ◽  
Time Frequency ◽  
Ae Signal

<p>The sliding surface deformation of the soil slope mainly presents progressive failure characteristics, and serial acoustic emission (AE) signals are generated during the deformation process of progressive landslide. A model test aiming at reproducing the typical shear surface deformation of a soil slope is designed. The displacement, AE data and corresponding time-frequency characteristics are comprehensively analyzed to evaluate the progressive deformation behavior. Comparisons with different granular backfills measurements show that cumulative AE count increase proportionally with the shear surface displacement, and the experiments demonstrate that the glass sand backfill exhibits remarkable AE detection characteristics and stronger correlation results. Significantly, AE signal exhibits variational dominant frequencies at different deformation stages, and there is the significant phenomenon that not only the low frequency signals generated with a significantly increase number, at the same time the continuous high frequency signals appear during the accelerating deformation stage. Furthermore, from the statistical trend of the energy percentage of the high frequency band into 312.5~500 kHz, it’s found that the correlative energy proportion occupies up to 15%, or even higher during the accelerating stage, indicating that the landslide may be about to enter a severely dangerous stage. The experiments show that the frequency characteristic of the AE signal can be effectively used as the early warning index, which may be the promising reference of the field warning monitoring for the soil progressive landslides.</p>

scholarly journals TEM Microstructural Evolution and Formation Mechanism of Reaction Layer for 22MnB5 Steel Hot-Dipped in Al–10% Si

Coatings ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 467 ◽  
Author(s):  
Dongik Shin ◽  
Jeong-Yong Lee ◽  
Hoejun Heo ◽  
Chung-Yun Kang
Keyword(s):  
Formation Mechanism ◽  
Microstructural Evolution ◽  
Reaction Layer ◽  
Coating Layer ◽  
Vertical Section ◽  
Diffusion Reaction ◽  
Boron Steel ◽  
Formation Mechanisms ◽  
22Mnb5 Steel ◽  
Mechanism Of Reaction

Microstructural evolution and formation mechanism of reaction layer for 22MnB5 steel hot-dipped in Al–10Si (in wt %) alloy was investigated. The microstructural identification of the reaction layer was characterized via transmission electron microscopy and electron backscatter diffraction. In addition, the formation mechanisms of the phases were discussed with vertical section (isopleth) of the (Al–Si–Fe) ternary system. The solidified Al–Si coating layer consisted of three phases of Al, Si, and τ5 (Al8Fe2Si). The reaction layer on the Al–Si coating layer side is a fine τ5 phase (Al8Fe2Si) of 5 μm thickness. The layer on the steel side consisted of an η phase (Fe2Al5) of thickness of 500 nm or less. τ1 (Al2Fe3Si3, triclinic) phase of 200-nm-thickness was formed in the η phase, and κ phase (Fe3AlC) of 40–50 nm thickness was formed between η phase and steel. The τ5 phase was formed by isothermal solidification at 690 °C in the liquid Al–10 wt % Si when 3.73–29.0 wt % of Fe was dissolved from the boron steel into the Al–Si liquid bath. It was considered that the η phase was formed by the diffusion reaction of Al, Si, and Fe between τ5 and ferrite steel. κ (Fe3AlC) phase was formed by the reaction of the carbon, which is barely employed in η and τ phases, and diffused Al.

scholarly journals Beta Fleck formation in Titanium Alloys

2020 ◽  
Vol 321 ◽  
pp. 10001
Author(s):  
K. Kelkar ◽  
A Mitchell
Keyword(s):  
Titanium Alloys ◽  
Formation Mechanism ◽  
Defect Formation ◽  
Melting Rate ◽  
Vacuum Arc ◽  
Formation Mechanisms ◽  
Alloy Development ◽  
Vacuum Arc Remelting ◽  
Freckle Formation ◽  
Nickel Base

Beta fleck is a troublesome segregation defect in many titanium alloys. It has previously been investigated by several authors and appears to have two formation mechanisms, one similar to that of “freckle” in steels and nickel-base alloys, the other arising in the “crystal rain” effect seen in conventional steel ingots. The freckle defect has been extensively studied and several theories developed to account for its formation in both remelted ingots and directional castings. In this work we compare the findings of investigations into the nickel-base freckle formation mechanism to similar conditions in the vacuum arc remelting of titanium alloys. We find that there are strong similarities between the beta fleck formation conditions and the parameters related to the Rayleigh Number criterion for freckle formation. In particular, the dendritic solidification parameters and the density dependence on segregation coefficients both fit well with the conditions proposed to characterise freckle formation. The second formation mechanism arises in the columnar to equiax transition in solidification. The condition for the avoidance of the defect in the two cases is the shown to be the same, namely the use of a very low VAR melting rate, but that it is unlikely to be 100% successful in preventing defect formation. We propose that the techniques presently in use for alloy development in the superalloy field through optimising the composition for minimum sensitivity to freckle formation should be applied to the formulation of future titanium alloys; also that attention should be paid to developing the PAM process to provide suitable solidification conditions for defect absence in a final ingot.

scholarly journals Temporal-spatially transformed synthesis and formation mechanism of gold bellflowers

Nanoscale ◽  
2016 ◽  
Vol 8 (14) ◽  
pp. 7430-7434 ◽  
Author(s):  
Jing Lin ◽  
Molly G. Zhang ◽  
Yuxia Tang ◽  
Bronte Wen ◽  
Hao Hu ◽  
...  
Keyword(s):  
Formation Mechanism ◽  
Formation Mechanisms

We synthesized gold nanourchins, gold microspheres, and gold bellflowers in monophasic, biphasic, and triphasic systems, respectively, and investigated their formation mechanisms.

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