The welding process and the properties of welding instruments may improve the mechanical performance of an item. One of these properties is the length of the welding tool. This approach has a substantial effect on the mechanical strength of the metallic matrix. The current study used molecular dynamics modeling and LAMMPS software to evaluate the effect of welding tool length on the mechanical properties of a welded Cu-Ag metallic matrix. This simulation makes use of the Lennard-Jones potential function and the embedded atom model. First, the equilibrium phase of modeled samples was verified by changing the computation of kinetic and total energies. Next, the mechanical properties of the welded matrix were studied using the stated Young\'s modulus and ultimate strength. The stress-strain curve of samples demonstrated that the mechanical strength of atomic samples increased as the length of the welding tool (penetration depth) increased. Numerically, by increasing the tool penetration depth of Fe tools from 2 Å to 8 Å, Young\'s modulus and ultimate strength of the matrixes sample increase from 34.360 GPa to 1390.84 MPa to 38.44 GPa and 1510 MPa, respectively. This suggested that the length of the Fe welding tool significantly affected the mechanical properties of the welded metallic matrix. The longer the length of Fe welding tools, the more particles were involved, and consequently, more bonds were formed among the particles. Bonding among the particles caused changes in mechanical properties, such as greater ultimate strength. This method can optimize mechanical structures and be useful in various industries.

Geopolymer materials have long been known for their competitive properties against traditional construction materials. Their special features include high resistance to elevated temperatures and good fire resistance. They are typically used as insulating materials at temperatures not exceeding 100 °C (because they can achieve a thermal conductivity coefficient of 0.060 W/m × K or less under these conditions). Still, they can also be used as thermal insulation at temperatures exceeding 1000 °C. One technology that uses very high temperatures is metal welding technology, where temperatures often exceed as many as 3000 °C. Geopolymers, due to their properties, can also be an interesting new alternative in various welding applications. This paper presents the preliminary results of pot-proofing the resistance of geopolymers to temperatures exceeding 3000 °C. Test results of a foamed geopolymer insulating a steel substrate are presented, and a geopolymer mold for thermite rail welding was made and realistically tested. The results confirmed the feasibility of using cast geopolymer molds for thermite welding of railroad rails. The geopolymer material performed well during the test and no cracks or other damage occurred. The following article presents the potential of using geopolymer materials for welding applications.

The success rate of the electrosurgical high-frequency electric field welding technique lies in reasonable control of the welding time. However, the final impedance value used to control the welding time varies due to differences in tissue size and the welding method during the welding process. This study aims to introduce a new reference indicator not limited by impedance size from dynamic impedance to achieve an adequate weld strength with minimal thermal damage, providing feedback on the tissue welding effect in medical power supplies. End-to-end anastomosis experiments were conducted with porcine small intestine tissue under seven levels of compression pressure. The dynamic impedance changes were analyzed, combined with compression pressure, temperature, moisture, and collagen during welding. The welding process was divided into three stages according to the dynamic impedance, with impedance decreasing in Period Ⅰ and impedance increasing in Period Ⅲ. Period Ⅲ was the key to high-strength connections due to water evaporation and collagen reorganization. The dynamic impedance ratio is defined as the final impedance divided by the minimum impedance, and successful welding would be predicted when detecting the dynamic impedance ratio over 4 (n = 70, p < 0.001). Dynamic impedance monitoring can be used as a macroscopic real-time prediction of the anastomosis effect.

This paper presents high quality (2048 × 1532 pixels) Light Microscope steel images sampled from the welding fusion zone. The microstructure images were acquired from the Design of Experiments (22 full factorial design) planned to compare two different arc welding processes at two different arc welding energies [1]. The 400 raw images appear as they were captured by the microscope and they are categorized into four groups: that acquired from the Flux Cored Arc Welding process and that acquired from the Shielded Metal Arc Welding process; both of them run for high and low levels of arc energy. For the Flux Cored Arc Welding process, ASME SFA 5.20 E71T-5C(M) tubular wire was used, with a nominal diameter of 1.2 mm. For the Shielded Metal Arc Welding process, AWS E7018 coated electrodes were used, with nominal diameters of 3.25 mm (for the low energy level) and 5.00 mm (for the high energy level). The deposition of the beads was run on AISI 1010 steel plates in the flat position (bead-on-plate). Different proportions of primary grain boundary ferrite; polygonal ferrite; acicular ferrite; nonaligned side-plate ferrite and aligned side-plate ferrite can be observed in each image. This image dataset is ready to visual and automatic microstructure recognition and quantification. It can be a useful resource for computational intelligence research teams, e.g. [2], by offering images for handling as filtering, feature extraction, training, validation and testing in pattern recognition and machine learning techniques.

Real-time electric signal, matter transfer mode and welding pool behavior were obtained to investigate the effect of wires\' filling rate on arc stability and joints\' appearance during underwater wet flux-cored arc welding (FCAW). The electric signal results showed that arc stability first decreased and then increased rapidly because the raise of filling rate affected the number of charged particles and the electrical conductivity of welding arc atmosphere. Two typical transfer modes, globular repelled transfer mode and surface tension transfer mode, were observed in this study. The ratio of surface tension transition could be increased by adding wires\' filling rate. Meanwhile, the geometry of molten pool was changed and the distance between droplets to welding pool reduced as the filling rate increased. The fusion line became more regular and the radius of curvature increased under the effect of bubbles in the molten pool. As the filling rate improving, more slags on the welds surface were acquired and the welds were much flatter and smoother.

Recently, semiconducting nanofiber networks (NFNs) have been considered as one of the most promising platforms for large-area and low-cost electronics applications. However, the high contact resistance among stacking nanofibers remained to be a major challenge, leading to poor device performance and parasitic energy consumption. In this report, a controllable welding technique for NFNs was successfully demonstrated via a bioinspired capillary-driven process. The interfiber connections were well-achieved via a cooperative concept, combining localized capillary condensation and curvature-induced surface diffusion. With the improvements of the interfiber connections, the welded NFNs exhibited enhanced mechanical property and high electrical performance. The field-effect transistors (FETs) based on the welded Hf-doped In2O3 (InHfO) NFNs were demonstrated for the first time. Meanwhile, the mechanisms involved in the grain-boundary modulation for polycrystalline metal-oxide nanofibers were discussed. When the high-k ZrO x dielectric thin films were integrated into the FETs, the field-effect mobility and operating voltage were further improved to be 25 cm2 V-1 s-1 and 3 V, respectively. This is one of the best device performances among the reported nanofibers-based FETs. These results demonstrated the potencies of the capillary-driven welding process and grain-boundary modulation mechanism for metal-oxide NFNs, which could be applicable for high-performance, large-scale, and low-power functional electronics.