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Bu çalışmada Lee (2020) tarafından COVID-19 kriziyle ilişkili olası disfonksiyonel anksiyete vakalarını tanımlamak için geliştirilen, Koronavirüs Anksiyete Ölçeği (KAÖ)'nin, Türkçe geçerlik ve güvenirlik analizlerini gerçekleştirmek amaçlanmıştır. Gereç ve Yöntemler: Ölçeğin geçerlik çalışmaları için açıklayıcı ve doğrulayıcı faktör analizleri, güvenirlik çalışmaları için ise iç tutarlılık analizleri yapılmıştır. Bulgular: Elde edilen bulgulara göre, geçerlik ve güvenirlik çalışması yapılan KAÖ tek boyutlu ve beş sorudan oluşan orijinal ölçek ile aynı özellikler göstermektedir. İstatistiksel analiz sonucunda 5 soru ve tek boyuttan ölçeğin Cronbach Alfa güvenirlik katsayısı 0,832 olarak hesaplanmıştır. Tek faktörden ve 5 maddeden oluşan ölçeğin maddelerine ilişkin faktör yükleri 0,625 ve 0,784 arasında değişmektedir. Tartışma ve Sonuç: Gerçekleştirilen bu çalışma ile literatüre geçerli ve güvenilir bir KAÖ kazandırıldığı düşünülmektedir. Bu çalışma koronavirüsün yarattığı anksiyetinin ölçülmesinde ve toplum ruh sağlığının geliştirilmesinde gelecekteki araştırmalara referans olabileceği düşünülmektedir.

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This work focuses on developing the mathematical model of surface roughness (Ra) in the turning of Inconel 625 superalloy with cryogenically treated tungsten carbide inserts. The influence of cryogenic treated on the microstructure and hardness of tungsten carbide tools was also investigated for the as-received inserts and deep cryogenic treatment at − 196 °C for 12, 24, and 36 h conditions. Turning experiments have been performed according to an orthogonal array L16 with three parameters (cutting tool, feed rate, cutting speed) at different levels with a 1 mm depth of cut. The ideal cutting tool and cutting parameters were evaluated in terms of the surface roughness (Ra). Analysis of Variance has been applied to determine the percentage of each cutting factor. It has been observed that the cutting speed has a maximum with 66.28% contribution on Ra. The best optimal turning parameters are obtained as A3B3C1 according to S/N ration. The mathematical model of Ra has been developed by regression analysis. The developed model is tested with verification experiments and found to be in good agreement with the experimental results.

This study focuses on optimization of cutting conditions and numerical analysis of flank wear in milling of Inconel 625 superalloy using PVD AlTiN and CVD TiCN/Al2O3/TiN-coated carbide inserts. The milling experiments have been performed in CNC vertical machining centre according to Taguchi L18 orthogonal array. Finite element modelling of tool wear was performed using Deform 3D software. Analysis of variance was utilized to define the influences of the milling conditions on Vb. The results showed that the feed rate (with 41.5% contribution rate) is the most important parameter affecting Vb. The linear and quadratic regression analyses were used to estimate the results of the test. The regression analysis results showed that the estimated Vb values achieved by the quadratic regression model were more effective compared to the linear regression model. Statistical results revealed that the Taguchi method was successful to define optimum cutting parameters in the milling of Inconel 625.

Due to its superior properties such as high melting point (2617°C), high thermal conductivity and low thermal expansion at higher temperatures, molybdenum is a refractory metal and is used for making critical parts in defense, space, electronics and nuclear industries. High cost of molybdenum makes the selection of suitable cutting conditions imperative in machining operations in order to obtain the required surface quality and dimensional accuracy. In this study, suitable cutting tools and cutting parameters were aimed to be determined in terms of cutting forces (F c) and average surface roughness (R a) when shoulder milling commercially pure molybdenum. The milling tests were carried out at 0.05, 0.1, 0.15, 0.2 mm/tooth feed rates and 75, 100, 125, 150 m/min cutting speeds using four different cutting tools. The Taguchi's experimental design (L16 orthogonal array) technique was implemented. Analysis of variance was used to determine the effects of cutting tools and cutting parameters on R a and F c. The results showed that the feed rate is the most influential parameter for F c while the cutting speed is for R a. Keywords Pure molybdenum Á ANOVA Á Surface roughness Á Cutting forces List of symbols a p Radial depth of cut (mm) a e Axial depth of cut (mm) A 0 Optimum S/N ratio for A (cutting tool) (dB) B 0 Optimum S/N ratio for B (feed rate) (dB) C 0 Optimum S/N ratio for C (cutting speed) (dB) CI Confidence interval f Feed rate (mm/tooth) F c Main cutting force (N) N Total number of tests g G S/N ratio calculated at optimum level (dB) g G S/N averages of control factors (dB) n eff Confirmatory test number R a Average surface roughness (lm) S/N Signal/noise ratio (dB) V c Cutting speed (m/min) V e Error variance

SummaryIn this study, drillability experiments were carried out on the AISI H13 hot work steel which is difficult to machine. Uncoated and AlCrN-coated carbide drills, ø14 mm, were used at 4 cutting speeds (60, 75, 90 and 108 m/min) and three different feed rates (0.15, 0.20 and 0.25 mm/rev). As a result of the experimental work, it was observed that an increase in the feed rate caused an increased on the thrust force in the workpiece machined with both the uncoated and coated drills. While an increase in the cutting speed caused the thrust force to increase in operations performed with uncoated drills, the increased cutting speed led to a decreased torque. In contrast, an increase in the cutting speed caused both the thrust force and the torque to decrease in the operations with coated drills. Stresses occurring on the drills were analyzed and a mathematical model was developed using the finite element method and the ANSYS Workbench package software.

The field of mitral valve disease diagnosis and management is rapidly evolving. New understanding of pathophysiology and improvements in the adoption of sophisticated multimodality imaging modalities have led to early diagnosis and to more complex treatment. The most common cause of mitral regurgitation (MR) in the western world is in the primary alteration of the valve, which leads to degenerative leaflet prolapse due to chordal elongation or rupture and annular dilatation. Untreated, significant MR has a negative impact prognosis, leading to reduction of survival. In the setting of degenerative MR, surgical repair currently represents the standard of care. Treatment of asymptomatic patients with severe MR in the Valve Center of Excellence, in which successful repair reaches more than 95% and surgical mortality less than 1%, symbolizes the direction for the next years. Transcatheter mitral valve repair with different devices, more recently the chordal replacement ones, is providing good outcomes and became a therapeutic option in high-risk patients with degenerative MR. In the future, more advances are expected from further development of interventional techniques, careful evaluation and better patient selection. This review will focus on long-term surgical outcomes of mitral valve repair with artificial chordae and on the emerging transcatheter chordal repair devices as therapeutic options for degenerative MR patients.