ABSTRACT
In this study, Ti 6Al-4 V (grade 5) ELI alloy was machined with minimum energy and optimum surface quality and minimum tool wear. The appropriate cutting tool and suitable cutting parameters have been selected. As a result of the turning process, average surface roughness (Ra), tool wear and energy consumption were measured. The results have been analyzed by normality test, linear regression model, Taguchi analysis, ANOVA, Pareto graphics and multiple optimization method. It has been observed that high tool wear value increases Ra and energy consumption. In multiple optimization, it was concluded that it made predictions with 89,1% accuracy for Ra, 58,33% for tool wear, 96,75% for energy consumption. While the feed rate was the effective parameter for Ra and energy consumption, the effective parameter in tool wear was the cutting speed. Our study has revealed that by controlling energy consumption, surface quality can be maintained and tool wear can be controlled.
ABSTRACT
OBJECTIVE: This study was planned to assess the vena contracta (VC), flow convergence area (PISA) and jet area (JA) methods in evaluating the severity of mitral regurgitation (MR) and to test the accuracy of a proposed algorithm using these methods. METHODS: Eighty-seven patients with chronic MR were enrolled in the study. VC of < 0.3 cm, maximal MR flow rate calculated by PISA (Qmax) of < 72 cm3/sn and JA of < 4 cm2 were classified as mild MR. VC of > 0.5 cm, Qmax of > 240 cm3/sn and JA of > 8 cm2 were classified as severe MR. Whereas the values between these ranges were called to be moderate MR. The algorithm was planned as follows: In the first step, VC width was measured. If a patient has VC = 0.3-0.5 cm, it was used Qmax in the eccentric jets and JA in the central jets in the second step. The severity of MR were considered as severe, moderate and mild for > 50%, 21-49% and 20% of the regurgitant fraction calculated by the reference method (the quantitative Doppler method depending on aortic and mitral stroke volumes), respectively. RESULTS: The sensitivity of VC was low in differentiating between moderate and severe MR (63%). In eccentric jets, the regurgitant volume calculated by PISA was higher than that of reference method (70 +/- 49 vs. 59 +/- 29 cm3) and the JA was found to be less than that of central jets despite similar regurgitant fraction (6.8 +/- 3.2 vs. 8.5 +/- 3.3 cm2). The algorithm agreed well with the reference method and it was better than those of each tree methods (Cappa coefficients 0.89 vs. 0.65, 0.63 and 0.45 for VC, Qmax and JA; respectively). The accuracies of the algorithm in discriminating between mild and moderate MR or severe and non-severe MR were high (98% and 95%, respectively). CONCLUSIONS: The severity of MR can be determined accurately and simply by using VC, PISA and JA methods together.
