Patterning coexisted micro-/nanostructures for consequential camouflage via mechanical constraint harnessed surface instability

2021 ◽  
Vol 119 (26) ◽  
pp. 264103
Author(s):  
Bo Li ◽  
Yehui Wu ◽  
Ya Sun ◽  
Wentao Ma ◽  
Lei Jiang ◽  
...  
Keyword(s):  
Surface Instability ◽  
Mechanical Constraint

Effects of Interfacial Tension in Tunneling Microscopy. 2. Experimental Observation of Surface Instability

1996 ◽  
Vol 100 (46) ◽  
pp. 18229-18233 ◽  
Author(s):  
John F. T. Conroy ◽  
Vlado Hlady ◽  
Cynthia J. Bruckner-Lea ◽  
Jiří Janata
Keyword(s):  
Interfacial Tension ◽  
Experimental Observation ◽  
Surface Instability ◽  
Tunneling Microscopy

Stratigraphy and palaeoenvironmental interpretation of late Quaternary colluvial slope deposits in southern Africa

2021 ◽  
Author(s):  
J. Knight
Keyword(s):  
Southern Africa ◽  
Land Surface ◽  
Late Quaternary ◽  
Ecological Factors ◽  
Surface Instability ◽  
Sediment Supply ◽  
Spatial And Temporal Patterns ◽  
Catchment Scale ◽  
Accommodation Space ◽  
Slope Sediment

Abstract Slope and lowland sediment systems throughout southern Africa are dominated by the presence of colluvium with interbedded palaeosols and hardground duricrusts. These sediments correspond to phases of land surface instability and stability, respectively, during the late Quaternary. This study examines the stratigraphy and environmental interpretation of slope sediment records from specific sites in southern Africa for the period of marine isotope stages (MIS) 6 to 1 (~191 ka to present), informed by theoretical ideas of the dynamics of slope systems including sediment supply and accommodation space. Based on this analysis, phases of land surface instability and stability for the period MIS 6 to 1 are identified. The spatial and temporal patterns of land surface conditions are not a simple reflection of climate forcing, but rather reflect the workings of slope systems in response to climate in addition to the role of geologic, edaphic and ecological factors that operate within catchment-scale sediment systems. Considering these systems dynamics can yield a better understanding of the usefulness and limitations of slope sediment stratigraphies.

Correlation between wire feed speed and external mechanical constraint for enhanced process stability in underwater wet flux-cored arc welding

2018 ◽  
Vol 233 (10) ◽  
pp. 2061-2073 ◽  
Author(s):  
Jianfeng Wang ◽  
Qingjie Sun ◽  
Jiangkun Ma ◽  
Peng Jin ◽  
Tianzhu Sun ◽  
...  
Keyword(s):  
Welding Process ◽  
Electrical Signal ◽  
Feed Speed ◽  
Process Stability ◽  
Underwater Wet Welding ◽  
Extinction Process ◽  
Flux Cored Arc Welding ◽  
Wire Feed Speed ◽  
Wire Feed ◽  
Mechanical Constraint

It is a great challenge to improve the process stability in conventional underwater wet welding due to the formation of unstable bubble. In this study, mechanical constraint method was employed to interfere the bubble generated by underwater wet welding, and the new method was named as mechanical constraint assisted underwater wet welding. The aim of the study was to quantify the combined effect of wire feed speed and condition of mechanical constraint on the process stability in mechanical constraint assisted underwater wet welding. Experimental results demonstrated that the introduction of mechanical constraint not only suppressed the bubble without floating but also stabilized the arc burning process. The degree of influence of mechanical constraint, which changed with wire feed speed, played an important role during the mechanical constraint assisted underwater wet welding process. For all wire feed speeds, the fluctuations of welding electrical signal were decreased through introduction of mechanical constraint. The difference in the proportion of arc extinction process between underwater wet welding and mechanical constraint assisted underwater wet welding became less with increasing wire feed speed. At wire feed speed lower than 7.5 m/min, the improvement of process stability was very significant by mechanical constraint. However, the further improvement produced limited effect when the wire feed speed was greater than 7.5 m/min. The observation results showed that a better weld appearance was afforded at a large wire feed speed, corresponding to a lower variation coefficient.

scholarly journals Analysis for full face mechanical behaviors through spatial deduction model with real-time monitoring data

2021 ◽  
pp. 147592172110448
Author(s):  
Xuyan Tan ◽  
Yuhang Wang ◽  
Bowen Du ◽  
Junchen Ye ◽  
Weizhong Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Analysis ◽  
Data Driven ◽  
Monitoring Data ◽  
Tunnel Structure ◽  
Mechanical Behaviors ◽  
Proposed Model ◽  
Full Face ◽  
Cross Test ◽  
Mechanical Constraint

Mechanical analysis for the full face of tunnel structure is crucial to maintain stability, which is a challenge in classical analytical solutions and data analysis. Along this line, this study aims to develop a spatial deduction model to obtain the full-faced mechanical behaviors through integrating mechanical properties into pure data-driven model. The spatial tunnel structure is divided into many parts and reconstructed in a form of matrix. Then, the external load applied on structure in the field was considered to study the mechanical behaviors of tunnel. Based on the limited observed monitoring data in matrix and mechanical analysis results, a double-driven model was developed to obtain the full-faced information, in which the data-driven model was the dominant one and the mechanical constraint was the secondary one. To verify the presented spatial deduction model, cross-test was conducted through assuming partial monitoring data are unknown and regarding them as testing points. The well agreement between deduction results with actual monitoring results means the proposed model is reasonable. Therefore, it was employed to deduct both the current and historical performance of tunnel full face, which is crucial to prevent structural disasters.

scholarly journals Stiffness Increase Method of Wire Driven Systems using Interference of Driving Directions and Mechanical Constraint Directions.

2001 ◽  
Vol 19 (6) ◽  
pp. 753-759 ◽  
Author(s):  
Hitoshi Kino ◽  
Sigeru Yabe ◽  
Takeshi Shimamoto ◽  
Sadao Kawamura
Keyword(s):  
Driven Systems ◽  
Mechanical Constraint
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