To optimize the friction stir welding (FSW) process for automotive battery cases and to improve both the welding quality and structural stability, the process parameters were tested, taking the speed of the stirrer head (1,600, 1800, 2,000 r/min) and the welding speed (400, 500, 600 mm/min). The optimal range of parameters was identified by observing the microsection of the weld beads. The results show that weld-forming quality is better when the welding heat input efficiency is in the range of 4.0–4.5. Three parameter combinations – 1,600 r/min + 400 mm/min, 1,800 r/min + 400 mm/min, and 2,000 r/min + 500 mm/min – were selected to analyze the microstructural characteristics of the weld zone (WZ), thermomechanically affected zone (TMAZ), and heat-affected zone (HAZ), clarifying the influence law of parameters on the microstructural evolution of each zone. A deformation simulation of the weld-concentrated zone of the battery enclosure was conducted using welding simulation software. It was found that the smallest post-weld deformation and the best deformation uniformity of the enclosure were achieved when the process parameters were set to 2,000 r/min and 500 mm/min. This research can provide a theoretical basis and technical support for the formulation of FSW processes for automotive battery enclosures.
Electro-osmotically driven flow is increasingly utilized for moving fluids in biomedical micropumps and drug delivery devices without mechanical moving parts, but existing models simultaneously incorporate peristaltic wall motion, electro-osmosis and non-Newtonian (Casson) nanofluid behavior in a physiologically realistic diverging-tube geometry. A restriction that hinders design of next generation micropumps and organ-on-chip platforms. This study sets this gap by developing for the first time a combined analytical model of electro-osmotic peristaltic transport of a Casson nanofluid in a vertically oriented contracting–expanding diverging tube from the effects of Brownian diffusion, thermophoresis, buoyancy, viscous dissipation and wall slip. The governing mass, momentum, energy and concentration equations were treated by the Debye–Hückel and lubrication approximations and then solved analytically by the homotopy perturbation method (HPM), leading to the closed-form solutions for the velocity, pressure and temperature. The results indicate that a higher thermophoretic forcing increases the temperature and the axial speed, but a higher Brownian diffusion parameter decreases the temperature and the axial speed, and a higher electro-osmotic (Helmholtz–Smoluchowski) velocity parameter decreases the area of fluid trapping with a higher Brownian motion parameter. The slip and electro-osmotic velocity parameters were identified as the ones most strongly influencing the pumping performance, whereas the pressure rise and trapping behavior are mostly controlled by the Casson number, Brinkman number and Grashof number (103 to 107). The closed-form HPM solution was further validated against a data-driven spatial bidirectional long short-term memory (BiLSTM) network trained to reproduce the velocity, temperature and concentration fields; the network converged within about 250–300 epochs (training MSE ≈ 0.0012, validation MSE ≈ 0.0003) and its predictions matched the analytical solution closely, with absolute errors concentrated near zero across all sampled locations, confirming the physical reliability of the analytical model through an independent, physics-free cross-check. The results suggest that the electro-osmotic and nanofluid properties can be considered as an effective control parameter for maximizing the flow rate, heat transfer and desired trapping of particles in next generation micropumps and drug delivery microdevices.
The paper aims to evaluate the outstanding expertise in the Partitioned Weighted Residual Method (PWRM) in addressing the motion of a stretching disk surface in the Bödewadt flow of a radiative hybrid water/Cu+TiO2 nanofluidic model. A hybrid nanofluid is created by mixing copper and titanium dioxide nanomaterials with water. This work examines a closer examination of thermal transmission in the presence of a uniform porous substrate with a convective surface. The classical weighted residual scheme by partitioning is employed to address the transformed governing equations via suitable similarity variables. To evaluate the predictive capability of the Galerkin weighted-residual hybrid, ensuring stable and accurate resolution of the thermo-hydrodynamic interactions, a comparative analysis was conducted between simulation outputs and benchmark numerical data. Outcomes exhibited excellent agreement across tested scenarios. The analysis shows that a retarded Darcy number profiles are observed across radial, axial, and azimuthal momentum directions. The escalation in the angle of inclination prompts the redistribution of the Lorentz force modules acting on the electric conductivity of the hybrid nanofluid, which modifies the momentum balance. It is noted that when the Darcy numbers increase, this leads to a noticeable decrease in the radial stress, while increasing the magnetic factor caused to intensify the radial stress.
Earthen plaster used in traditional buildings often shows powdering, cracking, and debonding during service. This study used pull-off adhesion tests on earthen plaster applied to fired clay brick substrates to evaluate the effects of cement, polyvinyl alcohol (PVA), and straw fibers on adhesion performance. The highest pull-off adhesion strength was recorded for the optimal mix (25 % cement, 1.0 % PVA, 4.5 % straw), achieving 1.15 MPa with a 95 % confidence interval of approximately 1.06–1.24 MPa, indicating improved reliability and performance consistency. This study also developed a data-based installation to present the experimental results in physical form. The installation, titled What Can Soil Be, consists of modular units coated with earthen plaster on fired clay brick. In this work, the mean pull-off adhesion strength was represented by module size, while the confidence interval width (CI w) of the mean result, expressed as CI w, was represented by color and lighting. The installation was exhibited at the Cultural and Art Center of Chiang Mai University from July 17 to 27, 2025. By moving through the installation, viewers could compare differences in strength and CI w through changes in size, surface texture, and light. In this way, the experimental results were presented in a more direct and accessible form.
In this study, we have considered steady-state, incompressible, 2D boundary-layer flow of a Buongiorno nanofluid model over a semi-infinite vertical sheet, examining the combined influence of MHD, thermal radiation, chemical reaction, and velocity slip. The governing equations, derived from the conservation laws of mass, momentum, energy, and species concentration, are reduced to a system of nonlinear ordinary differential equations through the application of non-similarity transformations with the Keller box approach. This reliable finite-difference scheme works well for boundary-layer problems, which accommodate the complexities inherent in the relationships among the variables involved. The impact of many important factors on the velocity, temperature, and concentration profiles of nanoparticles is thoroughly examined. Results reveal that velocity slip significantly reduces the fluid velocity near the wall, while thermal radiation enhances heat transfer rates. Furthermore, chemical reaction effects suppress nanoparticle concentration within the boundary layer. This research presents a novel integration of Buongiorno’s nanofluid model with the combined effects that have not been extensively explored together in prior studies. Additionally, an excellent agreement is achieved when compared with the latest published literature. The findings contribute to a deeper understanding of non-Newtonian fluid behavior and theoretical understanding of nanofluid dynamics over a semi-infinite sheet, and offer guidance for the design of efficient thermal systems and chemical processing technologies.
