Multi-Response Optimization in Drilling of MWCNTs Reinforced GFRP Using Grey Relational Analysis

The present work concentrates on the use of Grey Relational Analysis for optimizing the drilling parameters like weight percentage of multi-wall carbon-nanotube (MWCNTs), cutting speed and feed rate on the thrust force and the delamination factor in the drilling of GFRP composites. Full factorial design is utilized for the trial. Analysis of variance (ANOVA) is applied to determine the significance of drilling parameters on multi-response. Considering the multi-response optimization results, which are acquired from the largest Grey Relational Grade (GRG), it is determined that optimal parameters are 1 wt. % MWCNTs, cutting speed 25 m/min, and feed rate 0.10 mm/rev to minimize concurrently thrust force and delamination factor. It is provided that the percentage development in GRG with the multi-response optimization is 50.53%. It is clearly indicated that the quality characteristics are crucially developed using this approach in the drilling of GFRP. According to the results of ANOVA of the GRG, the crucial factor is feed rate. Validation experiment was confirmed by computing the confidence level within the interval width. Eventually, results of validation experiment with the optimum drilling conditions settings have indicated that the proposed model develops overall performance of drilling process

Modeling and optimization of face milling process parameters for AISI 4140 steel

In this study, the effect of cutting parameters such as the depth of cut, feed rate, cutting speed and the number of inserts on surface roughness were investigated in the milling of the AISI 4140 steel. The optimal control factors for surface quality were detected by using the Taguchi technique. Experimental trials were designed according to the Taguchi L18 (2¹x3³) orthogonal array. The statistical effects of control factors on surface roughness have been established by using the analysis of variance (ANOVA). Optimal cutting parameters were obtained by using the S/N ratio values. The ANOVA results showed that the effective factors were the number of inserts and the feed rate on surface roughness. However, the depth of cut and the cutting speed showed an insignificant effect. Additionally, the First-order and Second-order regression analysis were conducted to estimate the performance characteristics of the experiment. The acquired regression equation results matched with the surface roughness measurement results. The optimal performance characteristics were obtained as a 0.5 mm depth of cut, 0.08 mm/rev feed rate, 325 m/min cutting speed and 1 number of inserts by using the Taguchi method. Additionally, the confirmation test results indicated that the Taguchi method was very prosperous in the optimization of the machining parameters to obtain the minimum surface roughness in the milling of the AISI 4140 steel

Optimization of machining parameters in face milling using multi-objective Taguchi technique

In this research, the effect of machining parameters on the various surface roughness characteristics (arithmetic average roughness (Ra), root mean square average roughness (Rq) and average maximum height of the profile (Rz)) in the milling of AISI 4140 steel were experimentally investigated. Depth of cut, feed rate, cutting speed and the number of insert were considered as control factors; Ra, Rz and Rq were considered as response factors. Experiments were designed considering Taguchi L9 orthogonal array. Multi signal-to-noise ratio was calculated for the response variables simultaneously. Analysis of variance was conducted to detect the significance of control factors on responses. Moreover, the percent contributions of the control factors on the surface roughness were obtained to be the number of insert (71.89 %), feed (19.74 %), cutting speed (5.08%) and depth of cut (3.29 %). Minimum surface roughness values for Ra, Rz and Rq were obtained at 325 m/min cutting speed, 0.08 mm/rev feed rate, 1 number of insert and 1 mm depth of cut by using multi-objective Taguchi technique

Resilience in Individuals with Gender Dysphoria: Association with Perceived Social Support and Discrimination

Objective: Psychological distress associated with discrimination is proposed to have an indirect effect on the development of mental disorders, through its negative influence on individual's cognitive, affective and social coping strategies. The aim of this study was to investigate the association between resilience, perceived social support, and perceived discrimination in individuals with gender dysphoria. Method: Individuals with gender dysphoria were assessed with Turkish validated forms of Resilience Scale for Adults (RSA), Multidimensional Scale of Perceived Social Support (MSPSS), Perceived Discrimination Scale (PDS), and Beck Depression Inventory (BDI). Diagnoses of mental disorders, history of suicide attempt and non-suicidal self injury were assessed with clinical interviews. Self-report forms were used to obtain demographic information and gender transition related features. Results: Participants' (n = 116, 88 trans men) median age was 25. Significantly low RSA scores, indicating poor resilience, were obtained in participants with lifetime (59.5 %) and present (27.6 %) diagnosis of any mental disorder, history of suicide attempt (23.3 %). There was significant direct correlation between RSA and MSPSS scores, inverse correlation with BDI and personal PDS scores, but not with group PDS. Regression analysis revealed that only friends domain score in MSPSS predicted better resilience, whereas personal perceived discrimination score predicted poor resilience. Conclusion: Findings support the association between poor resilience and vulnerability to mental and behavioral problems in individuals with gender dysphoria. The associations reveal the significance of addressing discrimination and assisting individuals with gender dysphoria in developing strategies to obtain peer support in providing mental health services.WoSScopusTr-Dizi

Giant Right Coronary Artery Aneurysm Associated with Coronary–Cameral Fistula

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Association between reduced levels of MEFV messenger RNA in peripheral blood leukocytes and acute inflammation

Objective. Familial Mediterranean fever (FMF) is associated with more than 70 missense mutations in the MEFV gene. The purpose of this study was to investigate the relative expression of messenger RNA (mRNA) for the MEFV gene in peripheral blood leukocytes (PBLs) obtained from patients with FMF during attacks of acute abdominal inflammation as well as during asymptomatic periods

Treatment Strategies and Outcomes of Coronary Artery Fistulas in a Turkish Adult Population

Objective: Congenital coronary artery fistulas (CAF) are uncommon abnormalities that are known as abnormal communications between a coronary artery and a cardiac chamber or a major vessel. Incidence of CAF ranges between 0.1% and 0.2% 2 in literature,howeyer, there is no detailed data on the incidence of CAF in a Turkish population. In this article, we evaluated the clinical manifestations, symptoms, chosen treatment strategies, and long term follow-up results of GAF in Turkish adult population. Material and Methods: In this multicenter study carried out between 2001 and 2009, a total of 25 400 angiograms which were taken for various reasons were evaluated retrospectively. Sex, age, clinical manifestations, symptoms, number of the fistulas, chosen treatment strategies, and long term follow up results of the study population were recorded and analyzed. Results: CAF were found in 32 of these cases (0.13%). Eighteen of the cases were males, and 14 were females with a median age of 57.6 years. Fifteen cases had surgery, graft-stent was applied to two cases and coil embolization was preferred in two cases. Thirteen cases were followed up under medical treatment. Graft stents were occluded after 4 and 6 months following implantation in left anterior descending artery in both cases, and hence, these patients required surgery. Mean follow-up period was 48 +/- 27 months. All cases were asymptomatic (at the end of the follow-up period) and were doing well. Conclusion: In conclusion, incidence of CAF was found as 0.13% in the study population, and surgical treatment and coil embolization were considerably successful compared to stent graft application in CAF patients