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    Comparative study of different drills for bone drilling: A systematic approach
    (Malaysian Orthopaedic Association, 2020) Pazarci, Ozhan; Torun, Y.; Ozturk, A.; Oztemur, Z.
    Introduction: The performance of the drilling process depends on the characteristics of the drilling equipment and surgeon’s skill. To our knowledge, no research has focused on multi-parameter analysis of the dynamic behaviour of drills during the drilling process. This study aimed to characterise the physical changes and effects of different drills attached to a robotic arm during drilling of artificial bones in a standardised experimental setup. Materials and Methods: Drilling processes using three brands of drills attached to a robotic arm were compared in terms of thrust force, vibration, noise level, speed deviation, and temperature. A standardised experimental setup was constructed, and measurement data were analysed statistically. Identical artificial bones were drilled 10 times with each drill. Results: Thrust force measurements, which varied through the cortex and medulla, showed expressive differences for each drill for maximum and mean values (p<0.001). Meaningful differences were obtained for mean vibration values and noise level (p<0.001). Speed variation measurements in drilling showed conspicuous differences with confident statistics (p<0.001). Induced temperature values were measured statistically for Drill 1, Drill 2, and Drill 3 as 78.38±11.49°C, 78.11±7.79°C, and 89.77±7.79°C, respectively. Conclusion: Thrust force and drill bit temperature were strongly correlated for each drill. Vibration values and noise level, which also had an influential relationship, were in the acceptable range for all experiments. Both thrust force and speed deviation information could be used to detect the drill bit status in the bone while drilling. © 2020, Malaysian Orthopaedic Association. All rights reserved.
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    Determination of problems in patients with post-laryngectomy
    (WILEY-BLACKWELL, 2013) Ozturk, A.; Mollaoglu, M.
    The purpose of this study is the determination of the physical and psychosocial problems of total and partial laryngectomies. A total of 25 patients, who were operated with the diagnosis of larynx carcinoma in 2010 at Gazi University Faculty of Medicine Otolaryngology Department, were included in the study. They were evaluated with the help of the Personal Information Form (PIF) and the Determination Form of Post Laryngectomy Problem (DFPLP) for the problems they encountered after the operation. Total laryngectomy (TL) was performed on 76% of patients. It was determined that patients undergoing total laryngectomy experienced some physical and psycho-social problems such as problems in sleep (31.6%), smell (52.6%), taste (36.8%), and difficulty in swallowing solid foods (36.8%). Furthermore in patients with TL surgery whilst 47.4% of them think that their sexual lives were affected rather negatively, this rate was determined as 33.3% in patients with partial laryngectomy surgery (PL). The psychosocial score averages of the patients who had smell and taste disorders were significantly lower (p<0.05). The patients, who underwent a laryngectomy operation, experienced many physical, social, and psychological problems. Thus, medical personnel also need to pay attention to these concomitant problems that occur during the treatment of the primary disease and the application of necessary supplementary treatments such as voice prosthesis, pre-op and post-op counseling, and anti-depressants seems significant in terms of increasing the life quality of the patients.
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    Measurements of Reynolds stresses in centrifugal compressor vaned diffusers
    (PROFESSIONAL ENGINEERING PUBLISHING LTD, 2008) Pinarbasi, A.; Guleren, K. M.; Ozturk, A.
    A phase lock loop sampling technique has been developed in order to perform detailed measurements for the flow field downstream of a turbomachinery rotor. Measurements have been carried out in the vaned diffuser of a low-speed centrifugal compressor using a triple hot wire anemometer. The phase lock loop technique employed in this work has provided a comprehensive representation of the complex three-dimensional unsteady flow in these diffusers. The diffuser vanes were found to have a significant influence on the flow in the vaneless space. The mixing out of the blade wakes is enhanced and accordingly the Reynolds stress levels drop rapidly between the impeller exit and the vane leading edge. The results provide an insight into the flow mechanisms responsible for the losses and hence can be used to develop better design strategies in the future. The flow also exhibits high levels of anisotropy, especially at the mid-vane positions. This suggests that basic Reynolds-averaged Navier-Stokes (RANS) models, including standard one- or two-equation models, might not be sufficient to accurately model the flow in centrifugal compressor diffusers.