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As one of the typical geological hazard, landslide seriously threatens the safe operation of buried pipelines. If the limit landslide displacement that the pipeline can bear can be accurately predicted, the pipeline failure accident can be effectively predicted combined with advanced landslide monitoring technology. In view of this, firstly, a pipe-soil interaction model with nonlinear contact was established and verified. Then, the effects of model parameters and boundary conditions on simulation results were discussed. Finally, the prediction method of the limit landslide displacement for stress/ strain criterion is researched. The conclusions are as follows. The nonlinear contact pipe-soil interaction model with infinite boundaries on both sides is more suitable for the mechanical response analysis of pipeline under real landslide conditions. Using this model, the large deformation and separation of pipeline and soil can be effective simulated by that model, the limit landslide displacement based on stress and strain criteria can also be predicted. This paper provides an effective technical means for the safety design of pipelines in mountainous areas and the prevention and control of landslide accidents. [ABSTRACT FROM AUTHOR]

In the present study, two-phase nanofluid flow in a three-dimensional system is modeled over a stretching infinite solar plate and the heat transfer analysis is performed for this problem. The governing equations are presented based on previous studies and the suitable solution method is recommended due to infinite boundary condition in the problem. Keller Box Method (KBM) using the Maple 15.0 mathematical software is applied as the solution method for the governing equation of the problem. The effect of some parameters existed in the equations (Pr (Prandtl number), Sc (Schmidt number), Nb (Brownian motion parameter), Nt (Thermophoresis parameter), λ=b/a (ratio of the stretching rate along y to x directions) and n (power-law index)), are discussed on the velocities, temperature, and nanoparticles concentration functions. As an important outcome, increasing both n and λ parameters, makes a reduction in shear stress, while it increase the Nusselt number function of heat transfer.

A novel kind of seismic isolation technique called "Periodic Barriers," which combines trench-type wave barriers and metamaterial, is introduced in this research. Metamaterial possesses a unique frequency-selective property that enables the metamaterial to manipulate the wave propagation. By infilling the metamaterials in the trench-type wave barriers, the periodic barriers are expected to display advantages of both the wave barriers and the metamaterials. The two-dimensional (2D) finite-element (FE) simulation is conducted to study the performance of the barriers adapting the metamaterial. This FE model is validated with the experiment on the metamaterial-based foundation. The convergence test on mesh size with different element types are investigated, and the minimum mesh size and property element type are determined for simulating the behavior of metamaterial. To simulate the unbounded domain, the absorbing boundary is implemented to eliminate the reflection from the boundaries. The dynamic responses obtained from models with infinite element boundary and viscoelastic boundary are found to converge with the increasing model size. To boost the computing efficiency, two analysis methods (fix-frequency harmonic analysis, and the time-history analysis) are adopted and found to have a strong correlation with each other. Based on the proposed modeling techniques and the analysis methods, the simulation of the periodic barriers embedded in the soil is performed. With various loading distance and the number of periodic barriers, the performance of the periodic barriers is found to comply with its theoretical frequency band gaps. [ABSTRACT FROM AUTHOR]

In this work, 3-D and two-phase nanofluid flow and heat transfer is modeled over a stretching infinite solar plate. The governing equations are presented based on previous studies. The infinite boundary condition and shortcoming of traditional analytical collocation method have been overcome in our study by changing the problem into a finite boundary problem with a new analytical method called optimal collocation method. The accuracy of results is examined by fourth order Runge- Kutta numerical method. Effect of some parameters, Prandtl number, Schmidt number, Brownian motion parameter, thermophoresis parameter, λ=b/a (ratio of the stretching rate along y- to x-directions), and power-law index on the velocities, temperature, and nanoparticles concentration functions are discussed. As an important outcome of our 3-D model analysis, it is found that increase in thermophoretic forces can enhance the thickness of both thermal and nanoparticle volume fraction boundary-layers. [ABSTRACT FROM AUTHOR]

Abstract: Let be a set of finite tournaments. We will give a necessary and sufficient condition for the -free homogeneous directed graph to be divisible; that is, that there is a partition of into two sets neither of which contains an isomorphic copy of . [Copyright &y& Elsevier]

In this study, main concern is focused on numerically solving the integro-differential-delay equations with variable coefficients and infinite boundary on half-line, proposing a matrix-collocation method based on the orthoexponential polynomials. The method is equipped with the collocation points and the hybridized matrix relations between the orthoexponential and Taylor polynomials, which enable us to convert an integral form with infinite boundary into a mathematical formulation. The method also directly establishes the verification of the existence and uniqueness of this integral form through a convergent result. In order to observe the validity of the method versus its computation limit, an error bound analysis is performed by using the upper bound of the orthoexponential polynomials. A computer module containing main infrastructure of the method is specifically designed and run for providing highly precise results. Thus, the numerical and graphical implementations are completely monitored in table and figures, respectively. Based on the comparisons and findings, one can state that the method is remarkable, dependable, and accurate for approaching the aforementioned equations. [ABSTRACT FROM AUTHOR]