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This study looks at how welding intensity, speed, voltage, and stick-out affect the structural and mechanical characteristics of metal inert gas (MIG) welding on SUS 201 stainless steel and C20 steel. The Taguchi method is used to optimize the study's experiment findings. The results show that the welding current has a more significant effect on the tensile test than the welding voltage, stick-out, and welding speed. Welding voltage has the lowest influence. In addition to the base metals' ferrite, pearlite, and austenite phases, the weld bead area contains martensite and bainite microstructures. The optimal parameters for the ultimate tensile strength (UTS), yield strength, and elongation values are a 110 amp welding current, 15 V of voltage, a 500 mm.min−1 welding speed, and a 10 mm stick-out. The confirmed UTS, yield strength, and elongation values are 452.78 MPa, 374.65 MPa, and 38.55%, respectively, comparable with the expected value derived using the Taguchi method. In the flexural test, the welding current is the most critical element affecting flexural strength. A welding current of 110 amp, an arc voltage of 15 V, a welding speed of 500 mm.min−1, and a stick-out of 12 mm are the ideal values for flexural strength. The flexural strength, confirmed at 1756.78 MPa, is more than that of the other samples. The study's conclusions can offer more details regarding the dissimilar welding industry. [ABSTRACT FROM AUTHOR]

This study examines the effects of stick-out, welding current, welding speed, and voltage on the mechanical characteristics and microstructure of MIG welding on SUS 304 stainless steel and S20C steel. The Taguchi method was used to maximize the experiment's outcomes. Fine columnar dendrites formed at fusion sites, and δ-ferrite phases with dark lines and shapes accumulated between the fusion line and the austenite phases. A welding current of 110 A, voltage of 15 V, welding speed of 500 mm/min, and stick-out of 12 mm were the optimal settings for the ultimate tensile strength (UTS). The UTS value confirmation was 469.4 MPa, which agrees with the estimated value determined using the Taguchi technique. The tensile test revealed that welding current had a far greater impact on mechanical qualities than welding voltage, speed, and stick-out distance. The ideal welding parameters for flexural strength were as follows: stick-out of 12 mm, arc voltage of 15 V, welding speed of 450 mm/min, and welding current of 110 amp. The Taguchi method is useful, as evidenced by the validation of the flexure strength of 1937.45 MPa, which is much greater than the other samples. The impact of the thermal annealing process on the mechanical characteristics of the dissimilar weld joints could be the subject of future research. The investigation results may offer more insightful information about the dissimilar welding field. [ABSTRACT FROM AUTHOR]

In this study, we present a novel approach to injection molding, focusing on the strength of weld lines in polyamide 6 (PA6) composite samples. By implementing a mold temperature significantly higher than the typical molding practice, which rarely exceeds 100°C, we assess the effects of advanced mold temperature management. The research introduces a newly engineered mold structure specifically designed for localized mold heating, distinguishing it as the 'novel cavity.' This innovative design is compared against traditional molding methods to highlight the improvements in weld line strength at elevated mold temperatures. To optimize the molding parameters, we apply an Artificial Neural Network (ANN) in conjunction with a Genetic Algorithm (GA). Our findings reveal that the optimal ultimate tensile strength (UTS) and elongation values are achieved with a filling time of 3.4 seconds, packing time of 0.8 seconds, melt temperature of 246°C, and a novel high mold temperature of 173°C. A specific sample demonstrated the best molding parameters at a filling time of 3.4 seconds, packing time of 0.4 seconds, melt temperature of 244°C, and mold temperature of 173°C, resulting in an elongation value of 582.6% and a UTS of 62.3 MPa. The most influential factor on the PA6 sample's UTS and elongation at the weld line was found to be the melt temperature, while the filling time had the least impact. SEM analysis of the fracture surfaces revealed ductile fractures with rough surfaces and grooves, indicative of the weld line areas' bonding quality. These insights pave the way for significant improvements in injection molding conditions, potentially revolutionizing the manufacturing process by enhancing the structural integrity of the weld lines in molded PA6 samples. [ABSTRACT FROM AUTHOR]

Weld line defects, commonly occurring during the plastic product manufacturing process, are caused by the merging of two opposing streams of molten plastic. The presence of weld lines harms the product's aesthetic appeal and durability. This study uses artificial neural networks to forecast the ultimate tensile strength of a PA6 composite incorporating 30% glass fibers (GFs). Data were collected from tensile strength tests and the technical parameters of injection molding. The packing pressure factor is the one that significantly affects the tensile strength value. The melt temperature has a significant impact on the product's strength as well. In contrast, the filling time factor has less impact than other factors. According to the scanning electron microscope result, the smooth fracture surface indicates the weld line area's high brittleness. Fiber bridging across the weld line area is evident in numerous fractured GF pieces on the fracture surface, which enhances this area. Tensile strength values vary based on the injection parameters, from 65.51 MPa to 73.19 MPa. In addition, the experimental data comprise the outcomes of the artificial neural networks (ANNs), with the maximum relative variation being only 4.63%. The results could improve the PA6 reinforced with 30% GF injection molding procedure with weld lines. In further research, mold temperature improvement should be considered an exemplary method for enhancing the weld line strength. [ABSTRACT FROM AUTHOR]

Leprosy is the second most prevalent mycobacterial disease globally. Despite the existence of an effective therapy, leprosy incidence has consistently remained above 200,000 cases per year since 2010. Numerous host genetic factors have been identified for leprosy that contribute to the persistently high case numbers. In the past decade, genetic epidemiology approaches, including genome-wide association studies (GWAS), identified more than 30 loci contributing to leprosy susceptibility. However, GWAS loci commonly encompass multiple genes, which poses a challenge to define causal candidates for each locus. To address this problem, we hypothesized that genes contributing to leprosy susceptibility differ in their frequencies of rare protein-altering variants between cases and controls. Using deep resequencing we assessed protein-coding variants for 34 genes located in GWAS or linkage loci in 555 Vietnamese leprosy cases and 500 healthy controls. We observed 234 nonsynonymous mutations in the targeted genes. A significant depletion of protein-altering variants was detected for the IL18R1 and BCL10 genes in leprosy cases. The IL18R1 gene is clustered with IL18RAP and IL1RL1 in the leprosy GWAS locus on chromosome 2q12.1. Moreover, in a recent GWAS we identified an HLA-independent signal of association with leprosy on chromosome 6p21. Here, we report amino acid changes in the CDSN and PSORS1C2 genes depleted in leprosy cases, indicating them as candidate genes in the chromosome 6p21 locus. Our results show that deep resequencing can identify leprosy candidate susceptibility genes that had been missed by classic linkage and association approaches.

Leprosy is a chronic disease caused by Mycobacterium leprae. Worldwide, more than 200,000 new patients are affected by leprosy annually, making it the second most common mycobacterial disease after tuberculosis. The MHC/HLA region has been consistently identified as carrying major leprosy susceptibility variants in different populations at times with inconsistent results. To establish the unambiguous molecular identity of classical HLA class I and class II leprosy susceptibility factors, we applied next-generation sequencing to genotype with high-resolution 11 HLA class I and class II genes in 1,155 individuals from a Vietnamese leprosy case-control sample. HLA alleles belonging to an extended haplotype from HLA-A to HLA-DPB1 were associated with risk to leprosy. This susceptibility signal could be reduced to the HLA-DRB1*10:01~ HLA-DQA1*01:05 alleles which were in complete linkage disequilibrium (LD). In addition, haplotypes containing HLA-DRB3~ HLA-DRB1*12:02 and HLA-C*07:06~ HLA-B*44:03~ HLA-DRB1*07:01 alleles were found as two independent protective factors for leprosy. Moreover, we replicated the previously associated HLA-DRB1*15:01 as leprosy risk factor and HLA-DRB1*04:05~HLA-DQA1*03:03 as protective alleles. When we narrowed the analysis to the single amino acid level, we found that the associations of the HLA alleles were largely captured by four independent amino acids at HLA-DRβ1 positions 57 (D) and 13 (F), HLA-B position 63 (E) and HLA-A position 19 (K). Hence, analyses at the amino acid level circumvented the ambiguity caused by strong LD of leprosy susceptibility HLA alleles and identified four distinct leprosy susceptibility factors.

Leprosy is a chronic infectious disease of the skin and peripheral nerves with a strong genetic predisposition. Recent genome-wide approaches have identified numerous common variants associated with leprosy, almost all in the Chinese population. We conducted the first family-based genome-wide association study of leprosy in 622 affected offspring from Vietnam, followed by replication in an independent sample of 1181 leprosy cases and 668 controls of the same ethnic origin. The most significant results were observed within the HLA region, in which six SNPs displayed genome-wide significant associations, all of which were replicated in the independent case/control sample. We investigated the signal in the HLA region in more detail, by conducting a multivariate analysis on the case/control sample of 319 GWAS-suggestive HLA hits for which evidence for replication was obtained. We identified three independently associated SNPs, two located in the HLA class I region (rs1265048: OR = 0.69 [0.58-0.80], combined p-value = 5.53x10-11; and rs114598080: OR = 1.47 [1.46-1.48], combined p-value = 8.77x10-13), and one located in the HLA class II region (rs3187964 (OR = 1.67 [1.55-1.80], combined p-value = 8.35x10-16). We also validated two previously identified risk factors for leprosy: the missense variant rs3764147 in the LACC1 gene (OR = 1.52 [1.41-1.63], combined p-value = 5.06x10-14), and the intergenic variant rs6871626 located close to the IL12B gene (OR = 0.73 [0.61-0.84], combined p-value = 6.44x10-8). These results shed new light on the genetic control of leprosy, by dissecting the influence of HLA SNPs, and validating the independent role of two additional variants in a large Vietnamese sample.

The influence of welding angle, welding current, travel speed, pulse time, and torch height on the geometry, macrostructure, and mechanical properties of Tungsten Inert Gas (TIG) orbital welding on an SUS 304 stainless steel pipe is investigated in this study. The results show that an electrode angle of 45° produces better weld joints than angles of 30°, 60°, 90°, and 120°. Furthermore, the electrode angle of 30° results in an acceptable weld width but a low depth of penetration (DOP) value. Welding current and weld speed have a significant impact on heat dispersion during TIG welding of an SUS 304 stainless steel pipe. The high welding current may result in blow-hole flaws, particularly near the conclusion of the welding process when heat is accumulated. A long torch height of 2 mm causes unevenness in the weld joints because the arc may be distorted when compared to shorter torch height cases. The pulse time of 0.2 s is too lengthy for a low-welding current situation because it will generate a small weld pool. As a result, the weld pool solidification process speeds up, and porosity emerges in the weld bead. A pulse time of 0.1 s results in a better weld joint. To avoid blow-hole creation, the welding current should be gradually reduced during the process. In addition, the Taguchi results demonstrate that the welding current has the greatest effect on the ultimate tensile strength (UTS) value, followed by welding speed, pulse time, electrode angle, and torch height. Furthermore, the ideal parameters for the UTS value are an electrode angle of 45°, a torch height of 2.0 mm, a welding current of 174 A, a welding speed of 72 mm/min, and a pulse time of 0.3 s. [ABSTRACT FROM AUTHOR]

Material additive or 3D printing technology has been recognized as a future manufacturing technique. The mechanical properties of products manufactured using 3D printing technology depend on many factors, especially the printing angle. Resin Castable Wax can be used as a matrix or scaffold for sensor devices in 3D printing. In this study, we explore the effects of printing angle on the mechanical properties of Resin Castable Wax V1 using the 3D stereolithography printing method. The samples are printed at three different printing angles of 0, 45, and 90°. Increasing the printing angle from 0 to 90° improves the tensile and compressive strengths. The sample printed at the angle of 90° shows the highest ultimate tensile and compressive strengths of 23.13 and 124.97 MPa, respectively, and vice versa for the sample printed at 0°. Because of the gradual inclination of the material toward the direction of load force and the larger printing boundary at a higher printing angle, the mechanical properties are improved when the printing angle is increased. These findings can be used to choose an appropriate printing angle for Resin Castable Wax V1. [ABSTRACT FROM AUTHOR]