International Journal of Computational Materials Science and Engineering

A new sampling point scheme with 13 evaluation points was introduced in this research study for 20-node brick elements. The new sampling points were located inside the brick element at the edges and the center point of the 20-node brick element. This integration scheme can be assumed to be an imitation of the Gaussian integration scheme. Standard benchmark problems were chosen from the different research works and compared with our proposed scheme. Finally, the proposed integration scheme achieves good results for 20-node brick elements on different performance parameters of finite element analysis.

The primary aim of this paper is to determine penetration and uplift resistances of two interfering pipelines buried in clay with a linear increase in strength. The advanced finite element limit analysis of upper and lower bound theorems is used to perform new limit analysis solutions for both penetration and uplift resistances of two interfering pipelines. The strength profiles of cohesive soils are the cases of normally consolidated clays in deep water by setting the shear strength at the ground surface to be zero and linearly increased with the depth. The twin pipelines have the same geometries and are simultaneously failed at the same magnitude of the failure uplift or bearing loads. There are three considered input parameters including the spacing between the pipes, the embedded depth of the pipes, and the unit weight of soils. All input parameters have significant influences on the penetration and uplift resistances of two interfering pipelines. Failure mechanisms of the problems are also investigated, and stability charts of the penetration and uplift resistances of two interfering pipelines are produced for practical uses in offshore geotechnical engineering.

Transistor, which is the building block of all electronic devices, has continuously scaled down its dimensions for better efficiency since the advent of CMOS circuits. Due to the thermal limit on the switching and various short-channel effects (SCEs), highly scaled MOSFETs are rendered unusable for low-power applications. Hence, the Tunnel Field-Effect Transistors (TFETs) are studied extensively for ultra-low-power applications. Further, multigate TFETs have emerged as the prime candidates for achieving better gate controllability. Throughout this work, a newly revised analytical model for Heterojunction Gate All Around (HJGAA) TFET is demonstrated using a 2D parabolic approximation equation. Analytical expressions are derived for both potential distribution and field distribution using appropriate boundary conditions. This distribution of electric fields is further used to measure the rate of tunneling output, and then we have extracted the drain current numerically. The findings indicate a substantial change in the drain current characteristics while reducing the SCE impacts to a considerable amount. Feasibility of the newly updated model is verified by comparing the results of the analytical model with the results of TCAD simulator.

We present density functional theory-based first principles study of magnetic properties of Mn-doped Mg${}_{n-2}$Mn₂O_n clusters. Mn-doped Mg_nO_n clusters are found to exhibit antiferromagnetic order. We show that ferromagnetic state can be stabilized by codoping with carbon at oxygen site. Our study suggests that the holes created due to C doping are responsible for the stabilization of ferromagnetism.

Numerical simulations aim to investigate the bifurcation caused by swirling flow between two coaxial vertical cylinders, and the fluid layers produced by the thermal gradient. The stability of both bifurcation and fluid layers by an axial magnetic field is analyzed. The finite-volume method is used to solve the governing Navier–Stokes, temperature and potential equations. A conducting viscous fluid characterized by a small Prandtl number $(\mathrm{\text{Pr}}=0.032)$ is placed in the gap between two coaxial cylinders. The combination of aspect ratio, $\gamma =1.5$ and Reynolds number, $\mathrm{\text{Re}}=1500$ for three annular gaps ($R=0.7,0.8$ and $0.9$) is compared in terms of flow stability, and heat transfer rates. Without a magnetic field, the vortex breakdown takes place near the inner cylinder due to the increased pumping action of the Ekman boundary layer. Fluid layered structures are developed by the competition between buoyancy and viscous forces. The increase in the magnitude of the magnetic field retarders the onset of the oscillatory instability caused by the disappearance of the vortex breakdown and reduces the number of fluid layers. The limits in which a vortex breakdown bubble manifests and the limits of transition from the multiple fluid layers to the single fluid layer are established.

In metallurgy, the microstructure study is very important to evaluate the properties and performances of a material. The Monte Carlo method is applied in so many fields of Engineering Science and it is a very effective method to examine the topology of the computer-simulated structures and exactly resembles the static behavior of the atoms. The effective 2D simulation was performed to understand the grain growth kinetics, under the influence of second phase particles (impurities) is a base to control the microstructure. The matrix size and $Q$-states are optimized. The grain growth exponent was investigated in a polycrystalline material using the $Q$-state Potts model under the Monte Carlo simulation. The effect of particles present within the belly of grains and pinning on the grain boundaries are observed. The mean grain size under second phase particles obeys the square root dependency.