Browsing by Author "Akkaya, S"

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    Design and manufacturing of an inductive liquid food heat treatment-filling system
    Çivi, C; Akkaya, S; Yilmaz, T
    In this study, an inductive heat treatment-filling system for milk pasteurization was designed and constructed. To identify the design parameters of the system, basic computational fluid dynamics (CFD) and lethality (reduction of a target pathogen during heating or thermal destruction of microorganisms) analyses were carried out simultaneously. In this context, the temperature-time combination of heated milk related to pipe design was taken into consideration. Induction calculations were made to provide the necessary heating for the selected flow rate and pipe construction material and diameter. Required frequency, power, and optimum coil design for the system were identified and validated. In the study, analyses were made for three different temperatures (90, 120, 150 degrees C) with different designs (straight pipe, flow breaker blades on the surface, central shaft) to define the required pipe length to obtain milk temperature (85 degrees C). Pipe dimensions were evaluated by CFD design and the shortest pipe length was 540 mm for the pipe having surface modification at 150 degrees C. However, for simplicity and applicability, a straight pipe at 90 degrees C constant surface temperature was selected for prototyping. From lethality calculations, 80 degrees C outlet temperature for 2700 mm pipe length was found to be sufficient and these parameters were considered for calculating induction parameters such as coil design and induction power. Experimental validation showed that heat balance was achieved compared to CFD calculations for the given system in steady condition; however, 130 s is required for reaching steady condition and this gap can be considered as come-up time. Although heat provided by induction was sufficient to heat milk to the desired temperature at the given pipe length, time was needed to heat the pipe to 90 degrees C with 25 degrees C milk passing inside at 1 L/s capacity.
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    Ultrasonographic Evaluation of the Flexor Pollicis Longus Tendon in Frequent Mobile Phone Texters
    Akkaya, N; Dogu, B; Ünlü, Z; Çarli, AB; Akkaya, S; Tekin, L; Özçakar, L
    Objective The aim of this study was to assess flexor pollicis longus tendon by using ultrasound imaging in frequent mobile phone texters. Subjects In total, 149 subjects, aged 18-40 yrs, were recruited as frequent mobile phone texters (n = 71) and infrequent texters (n = 78). Methods Demographic data and estimate frequency of texting were noted. Thumb pain during activity, range of motion for thumb joints, grip and pinch strengths, and Quick Disabilities of arm, shoulder, and hand were evaluated. Standardized bilateral ultrasound evaluations were performed using a linear array probe, and tendon area measurements were done with axial imaging at midthenar region and midproximal phalangeal region with manual trace technique. Results The groups were similar except for the mean estimate number of messages/month (P = 0.001). Whereas grip and pinch strength values were significantly higher (frequent texter group, P = 0.001; infrequent texter group, grip strength P = 0.018; pinch strengths, P = 0.001) on the texting side in both groups, flexor pollicis longus tendons were larger (P = 0.001) and the activity pain was higher (P = 0.005) on the texting sides only in the frequent texter group. Flexor pollicis longus thickness significantly correlated with messages/month only in the frequent texter group (r = 0.592, P = 0.001). Conclusions Flexor pollicis longus tendons seem to be thicker at the midthenar level in subjects who frequently use mobile phone texting. Because this increase in thickness parallels the number of messages per day, the authors believe that further studies are needed to elucidate whether such changes become problematic later on in life.