International Journal of Computational Materials Science and Engineering

In this study, we have calculated thermoelectric properties as a function of temperature and doping of the most stable phases of ZnO using first-principle calculations combined with semi-classical equation of Boltzmann. The nature of electrical conductivity is determined; the coefficient of Seebeck and figure of merit as a function of a charge carrier concentration of three structures studied are calculated. At high doping concentration, the rocksalt phase shows the best figure of merit.

Early-stage disease and cancer diagnosis are of particular importance for effective patient identification as well as their treatment. Breath analysis is a promising method for this purpose which can help to detect disease biomarkers. Benzaldehyde and Indole gas molecules as members of volatile organic compounds (VOCs) are composed of a proportion of the exhaled breath and changes in the level of them from breath can be considered for colorectal cancer biomarkers. Due to these incentives, we scrutinized the sensing behavior of Molybdenum disulfide (MoS${}_2)$ toward Benzaldehyde and Indole gas. We inspected the adsorption of the molecules on the pristine and Pd-, Pt-decorated MoS₂ by employing density functional nonequilibrium Green’s function (DFT-NEGF). It was disclosed that the molecules were weakly adsorbed upon the pristine MoS₂. Howbeit, after the decoration of the surface, the adsorption energy and charge transfer of the molecules were improved greatly. On the other hand, the band gap was decreased after metal decoration. For example, adsorption energy of −2.37eV and band gap of 1.32eV were achieved by interaction of Indole with Pd-decorated MoS₂ and it can be desorbed under UV light and at temperature of 698K with recovery time of 12.8s. Ergo, our analysis would help us better understand the adsorption mechanism of Pd- and Pt-decorated MoS₂-based gas sensors. It may open a new route in early disease detection and colorectal cancer monitoring.

In this paper, a novel model in a nonlocal porous thermoelastic solid is formulated based on the dual-phase-lag model (DPL), the Lord–Shulman theory and coupled theory with a memory-dependent derivative. The Laplace–Fourier technique is used to solve the problem and to obtain the exact expressions of physical fields. Numerical calculation of temperature, displacement, change in the volume fraction and stress is carried out and displayed graphically. Comparisons are made with the results predicted in the absence and presence of the gravity field as well as a nonlocal parameter. Comparisons are also made with results for different memory Kernel.

Numerical modeling of concrete fractures is of prime importance in the durability assessment of civil engineering structures. The phase field model has been demonstrated as a promising framework to simulate crack propagation in brittle material while using the many existing techniques. In this paper, we discuss choosing the most appropriate phase field model for describing the fracture behavior of concrete. More specifically, we present a detailed analysis of the existing models, which have been created by combining different spectral decompositions and crack density functions. The numerical simulation predictions are confronted with the experimental observation of a benchmark problem from the literature. The obtained results showed that the extensive/ compressive decomposition and the quadratic crack density function are the most suitable models to study concrete cracking behavior. The investigation’s size effects demonstrated heterogeneities played an important role in concrete’s post-cracking behavior and softening branches, especially for the small concrete structure.

The nested tube system is a cost-efficient energy absorbing device that is particularly crucial for applications with constrained squeeze zones and space. Using the triple continuous nested tube (TCNT) method for nesting is quite useful. The single-stage mode and two-stage mode are its two distinctive force–displacement curve forms. In this study, finite element models suitable for TCNT structures were developed using Abaqus software, and several control groups were constructed according to different initial collapse loads. Through an in-depth analysis of each component of the TCNT, it is discovered that the stiffness competition between the two inner rings is the primary factor contributing to the step-like mechanical response. The TCNT system comprehensively outperforms the conventional single ring design for specific energy absorption (SEA). The prediction equation regarding the initial collapse load of this system is also discussed in this paper. Since the relative errors of the theoretical and numerical solutions are more concentrated, the accuracy can be increased by the amplification factor. The final polynomial fit equation obtained gives a glimpse of the full force–displacement curve.

The use of solar air heaters (SAH), which convert solar energy into heat energy, is one of the most efficient methods currently available for capturing the energy of the sun. However, because SAH have lower thermal efficiency, researchers have been concentrating on developing methods to modify the flow field to artificially boost thermal performance. In this work, a numerical investigation that focuses on a SAH that has been deliberately roughened using broken arc ribs is presented. This numerical analysis aims to determine the impact of incorporating broken arc ribs compared to smooth ones and how various roughness factors affect the friction factor and Nusselt number (Nu). The RNG k-$𝜀$ turbulence model was used for the simulation. To solve the continuity, momentum, and energy equations, version R19.2 of Ansys FLUENT software was used. The results of the CFD study show that the average Nusselt number increases if there is a greater relative roughness pitch, and it achieves its highest value once relative roughness pitch ($p/e)=12$. The friction factor, on the other side, decreases as the Reynolds number (Re) increases, reaching its lowest value when $p/e=12$ and $\mathrm{\text{Re}}=18,000$. Maximum value of the thermohydraulic performance factor is observed to be 1.92 when applied to the geometry that corresponds to relative roughness height ($e/D)=0.037$, ($p/e)=12$, and $\mathrm{\text{Re}}=6000$.