Yazar "Ateş, Hakan" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • Küçük Resim Yok
    Öğe
    Effect of porosity content on the weldability of powder metal parts produced by friction stir welding
    (Trans Tech Publications Ltd, 2007) Kurt, Adem; Uygur, İlyas; Ateş, Hakan
    Friction stir welding technique (FSW) has many advantages in terms of tool design, rotational speed and traveling speed, and can be adjusted in a precise manner. It enables heat input into the system to be controlled. In this study, Aluminum powders were compacted at 350,400 and 450 MPa pressure and sintered at 450 degrees C temperature for 30 minutes in Ar atmosphere. Sintered powder metal parts were joined to each other by FSW at the speed of 1800 rpm and traveling welding speed 200 mm/min under a constant friction force. The results show that the amount of porosity affects the welclability of powder metallurgy (P/M) parts. Furthermore, the porosity and microstructural evolution of the Aluminum also affected the hardness values of the tested materials.
  • Küçük Resim Yok
    Öğe
    Effects of temperature on the weldability of powder metal parts joined by diffusion welding
    (Trans Tech Publications Ltd, 2007) Kurt, Adem; Uygur, İlyas; Ateş, Hakan
    Diffusion welding is an advanced bonding process in which similar or dissimilar materials can be bonded in solid state. In this study, aluminium composite (5% and 15% WC) powders were compacted at 450 MPa pressure and sintered at 550 degrees C for 45 minutes in argon atmosphere.and joined each other by diffusion bonding. The bonding temperatures (585 degrees C, 600 degrees C, 615 degrees C) and dwell time (185 min) were chosen for the welding process at constant 20 MPa. It has been observed that these variations on the welding parameter strongly affected the microstructure and the weldability of the materials.
  • Küçük Resim Yok
    Öğe
    Is the Atraumatic Spinal Needle a Better Choice in Younger Patients? A Comparison of 25G Spinal Needles in a Group of General Surgical Patients Below 40 Years of Age
    (2016) Bayır, Hakan; Dağlı, Recai; Erbesler, Zeynel Abidin; Kocaoğlu, Nazan; Yıldız, İsa; Ateş, Hakan
    Introduction: One of the important spinal anesthesia complications is the occurrence of postdural puncture headache (PDPH). The incidence of PDPH is related to the age, the size and tip shape of the spinal needle used and the type of surgery. Incidence may vary depending on the type and size of needle. This study was conducted to compare the frequency of PDPH using different kind of spinal needles.Methods: Data of 81 patients undergoing spinal anesthesia for lower abdominal surgery were collected for the study. Patients were divided into three groups as Group Q (n = 27), Group P (n=27) and Group A (n = 27) according to the spinal needle used for spinal anesthesia. Headache incidences during five days period postoperatively were noted.Results: The overall incidence of PDPH in this young adult population was 13.6% (11 patients of 81). PDPB was encountered in 14.8%, 11.1% and 14.8% of patients in Groups A, Q and P, respectively.Conclusion: All spinal needles used in our study have the potential to lead to PDPH in young patients undergoing spinal anesthesia for lower abdominal surgery. We did not see any advantage of using 25G Atraumatic spinal needle in young patients.