Investigation of the effective parameters on welding residual stress in GTAW of aluminum cylindrical shell

77-86The present work aims to study the influence of different geometrical, technological, and material parameters on residual stress in tungsten inert gas butt-welded aluminum cylinder. In order to present a simple analytical model to estimate the welding residual stress, the Taguchi L18 array has been employed with one 6-level factor and four 3-level factors. A 3D coupled thermo-mechanical finite element model considering temperature-dependent material properties has been developed to determine the welding residual stress in all experiments. The numerical model has been validated using the hole-drilling method. Using statistical analysis, the order of factors based on their effect on residual stress has been determined as yield strength, length, thickness, heat input, and finally diameter. The residual stress increases with an increase in yield strength, diameter, and heat input, while decreases with an increase in thickness. Contribution of each parameter on residual stress has been specified using variance analysis; yield strength with 99.6% contribution is the most significant factor, while diameter has insignificant impact. Finally, high accuracy equations have been proposed to calculate the welding residual stress

Association of two high-risk strains of human papillomavirus (HPV18 and HPV16) with breast cancer in the patients using polymerase chain reaction

Introduction: Two high-risk strains of human papillomavirus (HPV18 and HPV16) immortalize human mammary epithelial cells and reduce their growth factor requirements. Recent studies have identified HPV in a broad range of breast cancer samples. Therefore, the study aimed to assess the association of the mentioned high-risk HPV strains (HPV18, HPV16) with breast cancer in the patients using polymerase chain reaction (PCR) due to the increasing prevalence of breast cancer. Methods: The current work was a retrospective study involving 60 participants (40 patients with breast cancer and 20 healthy people) at Tabriz University of Medical Sciences in 2018-2019. The participants were selected using a convenience sampling method. PCR was used to detect DNA genomes of HPV18 and HPV16. Data was analyzed using Phi and Cramér’s V with SPSS v. 21 by taking into account OR=95% and P=0.05. Results: There was a significant relationship (P value=0.014) between HPV18 and HPV16 infection and breast cancer. Conclusion: A significant relationship was found between the presence of DNA genomes of HPV16 and HPV18 and breast cancer. Therefore, HPV has a significant role in breast cancer

Nicotine Dependence Severity and Revised Reinforcement Sensitivity Theory: Assessing the Mediating Role of Risky Decision Making Using Path Analysis

Background: Gray’s revised Reinforcement Sensitivity Theory (r-RST) is a neuropsychologicalexplanation of personality that has been broadly used in substance use disorders. Although theBehavioral Approach System (BAS) is strongly related to nicotine dependence, findings inBehavioral Inhibition System (BIS) are controversial and there is little information about therole of the Fight/Flight/Freeze System (FFFS) in nicotine dependence. The purpose of thepresent study was to evaluate the mediating role of Risky Decision Making (RDM) in thisrelationship to clarify the controversy and fill the gap.Methods: The final sample of this correlation study comprised of 347 university students (age,Mean±SD 23.2±6.7) who completed two self-report measures, including the Fagerstrom TestFor Nicotine Dependence (FTND), Jackson-5 questionnaire of r-RST, and a computerizedIowa Gambling Task (IGT) to measure RDM. Pearson correlation and a path analysisframework were used to determine the simple, direct, and indirect effects of r-RST systems onnicotine dependence severity through RDM.Results: Using Amos, path analyses demonstrated significant direct and indirect effects ofBAS and FFFS/BIS on tobacco use. Also, the relationship between BAS/FFFS/BIS andtobacco use was shown to be mediated by RDM.Conclusion: It was demonstrated that the relationship among BAS /FFFS/BIS and tobaccouse can be partly explained using maladaptive RDM strategies, suggesting that decreasingreliance on decision-making in risky situations, while increasing the use of decision-makingskills educations in risky situations, and increasing the use of alternative sensation and funseeking by smoking and emotion regulation and mindfulness-based therapie

Investigation of the effective parameters on welding residual stress in GTAW of aluminum cylindrical shell

The present work aims to study the influence of different geometrical, technological, and material parameters on residualstress in tungsten inert gas butt-welded aluminum cylinder. In order to present a simple analytical model to estimate thewelding residual stress, the Taguchi L18 array has been employed with one 6-level factor and four 3-level factors. A 3Dcoupled thermo-mechanical finite element model considering temperature-dependent material properties has been developedto determine the welding residual stress in all experiments. The numerical model has been validated using the hole-drillingmethod. Using statistical analysis, the order of factors based on their effect on residual stress has been determined as yieldstrength, length, thickness, heat input, and finally diameter. The residual stress increases with an increase in yield strength,diameter, and heat input, while decreases with an increase in thickness. Contribution of each parameter on residual stress hasbeen specified using variance analysis; yield strength with 99.6% contribution is the most significant factor, while diameterhas insignificant impact. Finally, high accuracy equations have been proposed to calculate the welding residual stress