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Öğe Şehir içi doğalgaz borularındaki kaynak hatalarının tahribatsız ve tahribatlı muayene yöntemleri ile incelenmesi(Mehmet BULUT, 2021-06-21) Adin, Hamit; Doğan, Adnan; Adin, Mehmet ŞükrüDoğalgaz boru hatlarının imalat ve montajı aşamasında yapılan kontroller kalite, insan, çevre güvenliği ve emniyet bakımından çok önemlidir. Bu nedenle çalışmamızda, Mardin ili şehir içinde kullanılan doğalgaz boru hatlarının birleştirme kaynakları API 1104 standardına göre tahribatsız yöntemle muayene edilmiştir. Tahribatsız muayene için doğalgaz boru hattında kullanılan API 5L X42 standardındaki çelik boruların kaynaklı birleşme yerlerinin radyografik resimleri çekilerek hataları tespit edilmiş ve çözümler geliştirilmeye çalışılmıştır. Radyografik muayeneler sonucunda, birleştirme kaynağındaki hataların kullanılan elektrottan kaynaklandığı tespit edilmiştir. Ayrıca, çalışma kapsamında borulardan alınan kaynaklı çekme numuneleri ile tahribatlı deneyler de yapılmıştır. Çekme deneyleri sonucunda, birleştirme kaynağı için en uygun elektrotun T2-Saf elektrotu olduğu görülmüştür.Öğe Fuel properties of biodiesels produced from blends of canola oil and animal tallow(SILA SCIENCE, 2011-04) Adin, Hamit; Altun, Şehmus; Yaşar, FevziBiodiesel is an alternative diesel fuel that can be produced from renewable feedstocks such as vegetable oil or animal fats by transesterification with methanol for using in diesel engines. The viscosity and density of biodiesel fuels are important parameters due to being key fuel properties for injection and combustion process of diesel engines. These fuel properties mainly depend on the feedstock which is used in the biodiesel production. Also, lubricity is an important for diesel engine fuels due to the fuel injection systems are lubricated by the fuel itself. In this study, the blends containing 0, 25, 50, 75 and 100% of food-grade canola oil/inedible animal tallow in volume basis were prepared and converted into methyl esters by base-catalyzed transesterification. Effect of canola oil ration in the feedstock on the viscosity, density and lubricity were investigated. Lubricity was determined using the high-frequency reciprocating rig (HFRR) test. Experimental results showed that the kinematics viscosity of increased as animal tallow ratio increased in the feedstock, as animal tallow itself is more viscous than canola oil. Also, density did not change much when blended feedstocks were used. Besides, it was observed that lubricity of biodiesel fuels from blended feedstocks was slightly get worse compared with pure biodiesels.Öğe Determination of fatigue life of the unidirectional GFRP/Al hybridcomposite laminates(Elsevier, 2019-06-01) Deniz, Mehmet Emin; Aydin, FıratThis paper investigates the effects of loading rate andfiber orientation on the fatigue behavior of the uni-directional glass-fiber reinforced-plastic/aluminum (GFRP/Al) hybrid laminated (GLARE-2) plates. Fatigue testswere performed at three kinds of stress ratios (R = 0.3, 0.1, and−0.1) on specimens with differentfiber or-ientations,θ= 0°, 15°, 30°, 45°, 60°, 75°, and 90°, in the GFRP layers. All the fatigue results to be presented inthis article were obtained in repeated tension-tension and tension-compression at stress ratios of 0.3, 0.1, and−0.1, and the results were compared with each other. It has been shown that the specimens have the highestfatigue life in thefiber orientation direction at R = 0.3 loading rate. Also, it has been shown that the fatigue lifeof the specimens decreases as the loading rate decreases.Öğe The effect of angle on the strain of scarf lap joints subjected to tensile loads(Elsevier, 2011-09-02) Adin, HamitIn this paper, the mechanical behavior of the scarf lap joints (SLJs) bonded with adhesive (Vinylester Atlac 580) under a tensile load was analyzed. The effects of scarf angle at the interface strain distributions of SLJs were examined. The stress analyses were performed via three dimensional Finite Element Method (3D-FEM). The 3D-FEM code employed was Ansys (12.0). Experimental results were compared with the 3D-FEM results and were found quite reasonable. The results indicated that the maximum values of the normalized epsilon(x) strain values were determined at 0 = 60 degrees in all joints.Öğe Microstructure and mechanical properties of AA7075/AA5182 jointed byFSW(Elsevier, 2019-06) Çetkin, Edip; Çelik, Yahya Hışman; Temiz, ŞemsettinIn this study, AA7075 and AA5182 aluminium alloys were joined using different rotation speeds (980, 1325 and 1800 rpm), feed rates (108 and 233 mm/min) and stirred pins having two different geometries (conical helical and triangular). Microstructures of welding joints were examined by an optical microscope and a scanning electron microscope (SEM). Vickers hardness measurements were performed in the welding zone of samples removed from each welded plate. Tensile and fatigue tests were also applied to the test specimens taken from the welded plates. After the tensile tests, the surface fractures and possible welding defects were scanned via SEM. The best mechanical properties were obtained when conical helical shape stirrer pins were used. The values were 265 MPa for tensile test and 159 MPa for fatigue test. The hardness value was very close to each other and varied depending on the rotation speed. The highest hardness value was determined as 87 HV in the weld center at 1325-rpm rotation speed.
