scholarly journals A Theoretical Model to Predict the Critical Hydraulic Gradient for Soil Particle Movement under Two-Dimensional Seepage Flow

Water ◽  
2017 ◽  
Vol 9 (11) ◽  
pp. 828 ◽  
Author(s):  
Zhe Huang ◽  
Yuchuan Bai ◽  
Haijue Xu ◽  
Yufen Cao ◽  
Xiao Hu
Keyword(s):  
Theoretical Model ◽  
Seepage Flow ◽  
Hydraulic Gradient ◽  
Soil Particle ◽  
Two Dimensional ◽  
Particle Movement ◽  
Critical Hydraulic Gradient

A hydromechanical relation governing internal stability of cohesionless soil

2011 ◽  
Vol 48 (3) ◽  
pp. 413-424 ◽  
Author(s):  
Ricardo Moffat ◽  
R. Jonathan Fannin
Keyword(s):  
Seepage Flow ◽  
Hydraulic Gradient ◽  
Cohesionless Soil ◽  
Cohesionless Soils ◽  
Critical Hydraulic Gradient ◽  
Internal Instability ◽  
Short Period ◽  
Flow Through ◽  
Permeameter Tests ◽  
Novel Concept

Results are presented from permeameter tests involving unidirectional seepage flow through reconstituted specimens of four widely graded cohesionless soils. The onset of instability is defined by a significant decrease in local hydraulic gradient over a relatively short period of time. The novel concept of a hydromechanical path in stress ([Formula: see text]) – gradient (ijk) space is proposed, which describes the response to seepage flow during testing and terminates at the value of critical hydraulic gradient. The path terminus establishes a hydromechanical boundary governing the onset of seepage-induced internal instability in one-dimensional flow. The boundary represents a failure envelope, which is different for each of the four soils tested. A ranking of seepage-induced instability for each soil, from most unstable to least unstable, is found similar, but not identical to, the susceptibility to internal instability determined from empirical analysis of the gradation shape.

scholarly journals Impacts of Consolidation Time on the Critical Hydraulic Gradient of Newly Deposited Silty Seabed in the Yellow River Delta

2021 ◽  
Vol 9 (3) ◽  
pp. 270
Author(s):  
Meiyun Tang ◽  
Yonggang Jia ◽  
Shaotong Zhang ◽  
Chenxi Wang ◽  
Hanlu Liu
Keyword(s):  
Yellow River ◽  
Yellow River Delta ◽  
Hydraulic Gradient ◽  
River Delta ◽  
Theoretical Formula ◽  
The Yellow River ◽  
The Yellow River Delta ◽  
Critical Hydraulic Gradient ◽  
Seepage Flows ◽  
The Yrd

The silty seabed in the Yellow River Delta (YRD) is exposed to deposition, liquefaction, and reconsolidation repeatedly, during which seepage flows are crucial to the seabed strength. In extreme cases, seepage flows could cause seepage failure (SF) in the seabed, endangering the offshore structures. A critical condition exists for the occurrence of SF, i.e., the critical hydraulic gradient (icr). Compared with cohesionless sands, the icr of cohesive sediments is more complex, and no universal evaluation theory is available yet. The present work first improved a self-designed annular flume to avoid SF along the sidewall, then simulated the SF process of the seabed with different consolidation times in order to explore the icr of newly deposited silty seabed in the YRD. It is found that the theoretical formula for icr of cohesionless soil grossly underestimated the icr of cohesive soil. The icr range of silty seabed in the YRD was 8–16, which was significantly affected by the cohesion and was inversely proportional to the seabed fluidization degree. SF could “pump” the sediments vertically from the interior of the seabed with a contribution to sediment resuspension of up to 93.2–96.8%. The higher the consolidation degree, the smaller the contribution will be.

Dynamic Response of Surface-Moored Vertical Barrier to Wave Action by Analog and Digital Simulation

1974 ◽  
Vol 96 (1) ◽  
pp. 335-342
Author(s):  
J. R. Fowler ◽  
E. I. Bailey
Keyword(s):  
Theoretical Model ◽  
Digital Simulation ◽  
Nonlinear Problems ◽  
Analog Computer ◽  
Two Dimensional ◽  
Test Program ◽  
Analog Simulation ◽  
Vertical Barrier ◽  
Amplitude Data ◽  
Lab Test

The two-dimensional dynamics of an oil containment barrier, which was designed to have very low tensile loads due to current and waves, were simulated with a theoretical model. The model was solved on both analog and digital computers, and a lab test program conducted to verify the model. For nonlinear problems such as this, for which “exact” solutions do not exist, the analog computer has many advantages, principally rapid parameter studies and convenient plotting output, plus giving the engineer a real time “feel” for the problem. The problem treated here was especially well-suited to analog simulation. Charts and graphs present maximum force and amplitude data, and experimental verification of the solution was obtained from wave tank studies.

Thermal Mapping, via Liquid Crystals, of the Temperature Field near a Heated Surgical Probe

1973 ◽  
Vol 95 (2) ◽  
pp. 250-256 ◽  
Author(s):  
T. E. Cooper ◽  
J. P. Groff
Keyword(s):  
Blood Flow ◽  
Temperature Field ◽  
Liquid Crystals ◽  
Theoretical Model ◽  
Wheatstone Bridge ◽  
Visual Display ◽  
Two Dimensional ◽  
Test Medium ◽  
One Dimensional ◽  
Water Test

This paper discusses the use of heat for producing clinical lesions in tissue and presents the design and analysis of a resistively heated surgical probe. The probe surface temperature is accurately maintained and controlled by using a Wheatstone bridge. The probe was embedded in a clear agar–water test medium, and the temperature field generated by the probe was measured with liquid crystals, a material that provides a visual display of certain isotherms. Experimental results compare within approximately 10 percent of a two-dimensional numerical solution. A one-dimensional theoretical model is also developed which examines the influence of blood flow on the temperature field.

THEORETICAL MODEL FOR THE CALCULATION OF OPTICAL PROPERTIES OF GOLD NANOPARTICLES

2010 ◽  
Vol 19 (03) ◽  
pp. 427-436
Author(s):  
A. MENDOZA-GARCÍA ◽  
A. ROMERO-DEPABLOS ◽  
M. A. ORTEGA ◽  
J. L. PAZ ◽  
L. ECHEVARRÍA
Keyword(s):  
Gold Nanoparticles ◽  
Refractive Index ◽  
Optical Properties ◽  
Theoretical Model ◽  
Absorption Coefficient ◽  
Molecular System ◽  
Two Dimensional ◽  
Box Models ◽  
Solvent Environment ◽  
Absorption And Dispersion

We have developed an analytical method to describe the optical properties of nanoparticles, whose results are in agreement with the observed experimental behavior according to the size of the nanoparticle under analysis. Our considerations to describe plasmonic absorption and dispersion are based on the combination of the two-level molecular system and the two-dimensional quantum box models. Employing the optical stochastic Bloch equations, we have determined the system's coherence, from which we have calculated expressions for the absorption coefficient and refractive index. The innovation of this methodology is that it allows us to take into account the solvent environment, which induce quantum effects not considered by classical treatments.

scholarly journals e-Campaigning in the 2014 European elections

2016 ◽  
Vol 24 (2) ◽  
pp. 105-117 ◽  
Author(s):  
Andrea Ceron ◽  
Luigi Curini
Keyword(s):  
Social Media ◽  
Theoretical Model ◽  
Inverse Relationship ◽  
Theoretical Framework ◽  
Theoretical Argument ◽  
Two Dimensional ◽  
European Elections ◽  
Electoral Campaigns ◽  
Electoral Campaign ◽  
The Relationship

The article explores the relationship between the incentives of parties to campaign on valence issues and the ideological proximity between one party and its competitors. Building from the existing literature, we provide a novel theoretical model that investigates this relationship in a two-dimensional multiparty system. Our theoretical argument is then tested focusing on the 2014 European electoral campaign in the five largest European countries, through an analysis of the messages posted by parties in their official Twitter accounts. Our results highlight an inverse relationship between a party’s distance from its neighbors and its likelihood to emphasize valence issues. However, as suggested in our theoretical framework, this effect is statistically significant only with respect to valence positive campaigning. Our findings have implications for the literature on valence competition, electoral campaigns, and social media.

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