This study investigated the influence of circumferential welding position and process parameters on bead geometry during multi-pass orbital gas tungsten arc welding (GTAW) of SUS304 stainless-steel pipes. Three-dimensional surface profiles were measured using a laser line scanner at the top (12H, −45° to 45°) and bottom (6H, 135° to 225°) circumferential regions. The incremental bead height and width of Passes 1 and 2 were quantitatively evaluated after excluding the first and last 10% of the measured region to minimize edge effects. Under identical root-pass conditions, the average Pass 1 bead height at 6H was 9.6% greater than that at 12H, whereas the bead width was 3.3% smaller. After Pass 2, the height difference increased to 12.0%, while the width difference remained small at 2.4%. Primary current, wire feed speed, and travel speed exhibited position-dependent effects on bead formation. Primary current affected the balance between vertical buildup and lateral spreading, wire feed speed consistently influenced bead width, and travel speed strongly affected bead buildup through changes in heat input, filler deposition per unit length, and molten-pool residence time. The greater reinforcement at 6H was attributed to gravity-dependent molten-metal accumulation during successive deposition. Interpolation of the primary-current experiments predicted that approximately 173 A at 12H and 175.5 A at 6H would produce comparable Pass 2 geometries of approximately 1.62 mm in height and 6.57 mm in width. These results demonstrate that circumferential bead uniformity can be improved through position-dependent parameter adjustment rather than identical welding conditions around the pipe circumference.

This study presents the synthesis of molybdenum disulfide (MoS₂) using flashlamp annealing and provides a comprehensive investigation of its structural and physical properties. The proposed flash-induced approach enables rapid production of high-quality MoS₂, offering superior process efficiency compared to conventional synthesis techniques. The structural, electronic, and thermal characteristics of the synthesized MoS₂ were systematically examined using multiple analytical methods, with particular attention to how synthesis conditions influence layer structure, crystallinity, and defect density. The results indicate that MoS₂ produced through this method exhibits material properties suitable for high-performance electronic devices and energy storage applications. Moreover, this work demonstrates the potential of flash-induced synthesis for scalable and practical fabrication of MoS₂-based nanomaterials, thereby contributing to the broader advancement of transition metal dichalcogenide technologies across diverse nanotechnology applications.

A flexible heater with high thermal efficiency and mechanical durability was developed by fabricating laser-induced porous graphene (LIPG) electrodes on polyimide films using a 532 nm green laser. Laser power, scan speed, and line distance were precisely optimized based on photothermal simulations to generate uniform porous graphene structures with large surface area and excellent heat dissipation characteristics. Raman, X-ray diffraction, and X-ray photoelectron spectroscopy analyses confirmed that the optimized LIPG exhibited highly graphitized features with low oxygen defects. Scanning electron microscope analysis revealed that porous morphologies formed only within a specific laser scan speed range, whereas excessive or insufficient irradiation resulted in collapsed or absent porosity. The serpentine-patterned LIPG heater maintained stable electrical resistance under repeated multidirectional bending, demonstrating excellent flexibility and mechanical stability. The heater also achieved rapid and uniform heating up to 80 °C within seconds, maintaining consistent temperature distribution even on curved surfaces.