scholarly journals Research on the Formation Mechanism of Loess Vertical Joints

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Chenxing Wang ◽  
Ruijun Jiang ◽  
Hong Wang ◽  
Tonglu Li ◽  
Haiwei Kang ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Formation Mechanism ◽  
Tensile Force ◽  
Column Experiment ◽  
Free Fall ◽  
Deposition Process ◽  
Force Balance ◽  
Horizontal Distance ◽  
Interparticle Force ◽  
Initial Deposition

The popular occurrence of vertical joints in loess formation aggravates the anisotropism of loess and contributes to various geohazards (e.g., slope failures and soil erosion). To alleviate the geohazards caused by the vertical joints, researches need to be carried out to investigate the formation mechanism of these vertical joints. However, the theoretical analysis of the vertical joints’ formation mechanism is limited up to now. In this study, we conducted a laboratory column experiment to observe joint development. Furthermore, using the unsaturated soil theory, we proposed a theoretical model to investigate the tensile stress that contributes to the formation of the loess vertical joint. In the experiment, the air-dried and crushed soil was sifted into the column, which simulates the free fall deposition process of the natural loess in China and contributes to a uniform state. 2500 ml of water was added at the top of the column. The topsoil experienced a wetting-drying process. During desaturation, 9 similar vertical joints were developed with similar horizontal distance. A theoretical model that calculates the interparticle force or tensile force between two adjacent particles was proposed based on the force balance equations. The theoretical model elucidates the phenomena in a laboratory experiment well and provides an insight into the formation mechanism of vertical joints in a uniform soil. The results highlight the generation of vertical joints in the initial deposition stage of loess with a uniform particle arrangement. Besides, the tensile force that contributes to the joint formation arises from the matric suction and surface tension of the solid-water-air contractile film.

scholarly journals Analyzing the Formation Mechanism of Cross-City Transportation Network Resilience

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Liang Wang ◽  
Xiaolong Xue ◽  
Weirui Xue ◽  
Beile Zhao
Keyword(s):  
Theoretical Model ◽  
Formation Mechanism ◽  
Transportation Network ◽  
Network Resilience ◽  
Railway Network ◽  
Network Nodes ◽  
General Meaning ◽  
Important Position ◽  
And Function ◽  
Constituent Elements

The formation mechanism of cross-city transportation network resilience occupies an important position in cross-city transportation network resilience management. This study analyzes the constituent elements of the cross-city transportation network and their interrelationships, and the connotation of cross-city transportation network resilience is defined from the general meaning of system resilience. Combining with the connotation of cross-city transportation network resilience, the specific formation process of cross-city transportation network resilience is analyzed and summarized from three stages, including resisting disturbance, absorbing disturbance, and function recovery. Taking cross-city transportation network nodes and systems as specific objects, the static and dynamic formation path of cross-city transportation network resilience is condensed. Based on the standard linear solid model, a theoretical model is constructed and solved for revealing the formation mechanism of cross-city transportation network resilience. Finally, the theoretical model of cross-city transportation network resilience proposed in this study is used for analyzing the China railway network resilience.

Analysis of the oscillatory wetting–dewetting motion of a volatile drop during the deposition of polymer on a solid substrate

Soft Matter ◽  
2019 ◽  
Vol 15 (17) ◽  
pp. 3580-3587 ◽  
Author(s):  
Anna Zigelman ◽  
Mohammad Abo Jabal ◽  
Ofer Manor
Keyword(s):  
Theoretical Model ◽  
Contact Line ◽  
Deposition Process ◽  
Solid Substrate

We employ a theoretical model to explain the wetting–dewetting motion of the contact line by incorporating opposing evaporation and Marangoni induced flows in the deposition process.

Characteristics of free overfall for supercritical flows

2007 ◽  
Vol 34 (2) ◽  
pp. 162-169 ◽  
Author(s):  
Nuray Denli Tokyay ◽  
Dilek Yildiz
Keyword(s):  
Rectangular Channel ◽  
Free Fall ◽  
Horizontal Distance ◽  
Supercritical Flow ◽  
Downstream Flow ◽  
Supercritical Flows ◽  
The Relationship ◽  
End Depth ◽  
Brink Depth ◽  
Free Overfall

The characteristics of supercritical flow at a vertical drop in a rectangular channel are studied experimentally to obtain information that would be valuable to designers of hydraulic structures. The relationship between the ratio of brink depth to the depth of upstream supercritical flow (i.e., end-depth ratio) and the Froude number is determined. Downstream from the vertical drop, the physical characteristics of the falling jet are examined, such as the height of the standing water behind the jet, the maximum horizontal distance of the jet hitting the floor downstream, the height and length of the splashing water, and the horizontal distance where the downstream flow gains uniformity. The energy loss between the drop and stable downstream flow is also studied.Key words: supercritical flow, brink depth, free fall.

scholarly journals Formation Mechanism of Well-Ordered Densely Packed Nanoparticle Superlattices Deposited from Gas Phase on Template-Free Surfaces

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Chang Liu ◽  
Fei Liu ◽  
Chen Jin ◽  
Sishi Zhang ◽  
Lianhua Zhang ◽  
...  
Keyword(s):  
Gas Phase ◽  
Formation Mechanism ◽  
Substrate Surface ◽  
Deposition Process ◽  
Solution Chemistry ◽  
Two Dimensional ◽  
Self Assembled Monolayer ◽  
Free Surfaces ◽  
Phase Cluster ◽  
Template Free

AbstractSuperlattices of nanoparticles are generally produced based on solution chemistry processes. In this paper, we demonstrate that self-assembled monolayer structures of nanoparticles with superlattice periodicities can also be produced on template-free surfaces in the gas-phase cluster beam deposition process. It is found that the packing of Fe nanoparticles corresponds to an average of two-dimensional densely packed lattice with a hexagonal summary. By controlling the nanoparticle coverage, the two-dimensional densely packed monolayer morphology can spread to the whole substrate surface being deposited. A formation mechanism of the ordered monolayers is proposed. The densely packed morphologies are formed by the balance between the diffusion rate of the nanoparticles and their filling speed on the substrate surface determined by the deposition rate, and the ordering of the nanoparticle arrays is driven by the inter-particle attractive interactions. The model is strongly supported by a series of carefully designed cluster deposition experiments.

scholarly journals Compositionally-Driven Formation Mechanism of Hierarchical Morphologies in Co-Deposited Immiscible Alloy Thin Films

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2635
Author(s):  
Max Powers ◽  
James A. Stewart ◽  
Rémi Dingreville ◽  
Benjamin K. Derby ◽  
Amit Misra
Keyword(s):  
Thin Films ◽  
Formation Mechanism ◽  
Threshold Value ◽  
Deposition Process ◽  
Immiscible Alloy ◽  
Multiple Length Scales ◽  
Constituent Element ◽  
The Difference ◽  
Microscopy Characterization

Co-deposited, immiscible alloy systems form hierarchical microstructures under specific deposition conditions that accentuate the difference in constituent element mobility. The mechanism leading to the formation of these unique hierarchical morphologies during the deposition process is difficult to identify, since the characterization of these microstructures is typically carried out post-deposition. We employ phase-field modeling to study the evolution of microstructures during deposition combined with microscopy characterization of experimentally deposited thin films to reveal the origin of the formation mechanism of hierarchical morphologies in co-deposited, immiscible alloy thin films. Our results trace this back to the significant influence of a local compositional driving force that occurs near the surface of the growing thin film. We show that local variations in the concentration of the vapor phase near the surface, resulting in nuclei (i.e., a cluster of atoms) on the film’s surface with an inhomogeneous composition, can trigger the simultaneous evolution of multiple concentration modulations across multiple length scales, leading to hierarchical morphologies. We show that locally, the concentration must be above a certain threshold value in order to generate distinct hierarchical morphologies in a single domain.

scholarly journals Control of microtubule assembly by extracellular matrix and externally applied strain

2001 ◽  
Vol 280 (3) ◽  
pp. C556-C564 ◽  
Author(s):  
A. J. Putnam ◽  
K. Schultz ◽  
D. J. Mooney
Keyword(s):  
Extracellular Matrix ◽  
Tensile Force ◽  
Control Point ◽  
Compressive Force ◽  
Step Change ◽  
Force Balance ◽  
Microtubule Assembly ◽  
Cell Phenotype ◽  
Mechanical Forces ◽  
Substrate Strain

A number of studies have suggested that externally applied mechanical forces and alterations in the intrinsic cell-extracellular matrix (ECM) force balance equivalently induce changes in cell phenotype. However, this possibility has never been directly tested. To test this hypothesis, we directly investigated the response of the microtubule (MT) cytoskeleton in smooth muscle cells to both mechanical signals and alterations in the ECM. A tensile force that resulted in a positive 10% step change in substrate strain increased MT mass by 34 ± 10% over static controls, independent of the cell adhesion ligand and tyrosine phosphorylation. Conversely, a compressive force that resulted in a negative 10% step change in substrate strain decreased MT mass by 40 ± 6% over static controls. In parallel, increasing the density of the ECM ligand fibronectin from 50 to 1,000 ng/cm2 in the absence of any applied force increased the amount of polymeric tubulin in the cell from 59 ± 11% to 81 ± 13% of the total cellular tubulin. These data are consistent with a model in which MT assembly is, in part, controlled by forces imposed on these structures, and they suggest a novel control point for MT assembly by altering the intrinsic cell-ECM force balance and applying external mechanical forces.

scholarly journals Parameter sensitivity analysis of the theoretical model of a CR-39-based direct 222Rn/220Rn progeny monitor

Nukleonika ◽  
2020 ◽  
Vol 65 (2) ◽  
pp. 95-98 ◽  
Author(s):  
Jun Hu ◽  
Masahiro Hosoda ◽  
Shinji Tokonami
Keyword(s):  
Sensitivity Analysis ◽  
Theoretical Model ◽  
Measurement Techniques ◽  
Deposition Process ◽  
Parameter Sensitivity ◽  
Parameter Sensitivity Analysis ◽  
Aerodynamic Parameters ◽  
Aerosol Parameters ◽  
Spearman’S Correlation ◽  
Attachment Process

AbstractThe deposition-based direct indoor 222Rn and 220Rn progeny measurement techniques are mostly affected by the indoor environmental conditions, such as the ventilation, concentration of condensation nuclei, and reactions with the structure and its furnishings. In this study, a theoretical model of a direct 222Rn and 220Rn progeny monitor based on allyl diglycol carbonate (ADC or CR-39) was established to analyse the factors that influence the detection process by using the parameter sensitivity analysis. The aerosol parameters contributed the highest to the variance, followed by the aerodynamic parameters. With respect to the result of the Spearman’s correlation analysis, the aerosol-related and the room-related parameters are positive, whereas the aerodynamic parameters – which affect the turbulence of indoor deposition – are negative. It means that both the attachment process and the deposition process of 222Rn and 220Rn progenies are important to the performance of the progeny monitor.

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