Static and dynamic stability of cracked multi-storey steel frames

Mustafa Sabuncu,Hasan Ozturk,Ahmed Yashar 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.58 No.1

Multi-storey frame structures are frequently exposed to static and dynamic forces. Therefore analyses of static (buckling) and dynamic stability come into prominence for these structures. In this study, the effects of number of storey, static and dynamic load parameters, crack depth and crack location on the in-plane static and dynamic stability of cracked multi-storey frame structures subjected to periodic loading have been investigated numerically by using the Finite Element Method. A crack element based on the Euler beam theory is developed by using the principles of fracture mechanics. The equation of motion for the cracked multi-storey frame subjected to periodic loading is achieved by Lagrange’s equation. The results obtained from the stability analysis are presented in three dimensional graphs and tables.

Electromyography-Guided Botulinum Toxin Injection Into the Cricothyroid Muscles in Bilateral Vocal Fold Abductor Paralysis

Mustafa Sahin,Ibrahim Aydogdu,Serdar Akyildiz,Munevver Erdinc,Kerem Ozturk,Fatih Ogut 대한이비인후과학회 2017 Clinical and Experimental Otorhinolaryngology Vol.10 No.2

Objectives. Bilateral vocal fold abductor paralysis (BVFAP) both deteriorates quality of life and may cause life-threatening respiratory problems. The aim of this study was to reduce respiratory symptoms in BVFAP patients using cricothyroid (CT) botulinum toxin (BTX) injection. Methods. Before and 2 weeks and 4 months after bilateral BTX injection into the CT muscles under electromyography; alterations in respiratory, acoustic, aerodynamic and quality of life parameters were evaluated in BVFAP patients with respiratory distress. For the respiratory evaluation modified Borg scale and spirometry, for the voice and aerodynamic evaluations Voice Handicap Index-30 (VHI-30), GRBAS, acoustic analysis (sound pressure level, F0, jitter%, shimmer%, noise-to-harmonic ratio) and maximum phonation time and for the quality of life assessment Short Form-36 (SF-36) form were used. Results. All patients were female with a mean age of 47±8.1 years. There was a mean time of 11.8±5.5 (minimum 2, maximum 23) months between BVFAP development and BTX injection. In all cases, other than one case with unknown aetiology, the cause of vocal fold paralysis was prior thyroid surgery. In total 18.6±3.1 units of BTX were applied to the CTs. In the preinjection period, and the 2nd week and 4th month after injection, the Borg dyspnea scale was 7.3/5.3/5.0, FIV1 (forced inspiratory volume in one second) was 1.7/1.7/1.8 L, peak expiratory flow (PEF) was 1.4/1.7/2.1 L/sec, maximum phonation time was 7.0/6.4/6.2 seconds and VHI-30 was 63.2/52.2/61.7 respectively. There was no significant alteration in acoustic analysis parameters. Many of the patients reported transient dysphagia within the first week. There were insignificant increases in SF-36 sub-scale values. Conclusion. After BTX injection, improvements in the mean Borg score, PEF and FIV1 values and SF-36 sub-scale scores showed the restricted success of this approach. This modality may be kept in mind as a transient treatment option for patients refused persistent tracheotomy or ablative airway surgeries.

Effects of Ensiling Alfalfa with Whole-crop Maize on the Chemical Composition and Nutritive Value of Silage Mixtures

Ozturk, Durmus,Kizilsimsek, Mustafa,Kamalak, Adem,Canbolat, Onder,Ozkan, Cagri Ozgur Asian Australasian Association of Animal Productio 2006 Animal Bioscience Vol.19 No.4

The aim of this study was to evaluate the chemical composition, in vitro DM degradability, ME and OMD of alfalfa-maize silage mixtures in comparison to pure maize and alfalfa silages, and to test the existence of associative effects of ensiling alfalfa forage with whole-crop maize using the in vitro gas production technique. Ensiling alfalfa with whole-crop maize had a significant (p<0.001) effect on chemical composition, pH, in vitro DM degradability, OMD and estimated ME values of mixtures. DM content of the resultant silages significantly increased with increasing proportion of whole-crop maize in the mixtures, whereas the pH value, crude protein (CP), acid detergent fibre (ADF) and ash contents of mixtures decreased due to the dilution effect of whole-crop maize which was low in CP, ADF and ash. The pH values of all alfalfa-maize silage mixtures were at the desired level for quality silage. Gas production of alfalfa-maize silage mixtures at all incubation times except 12 h increased with increasing proportion of whole-crop maize. When alfalfa was mixed with whole-crop maize in the ratio 40:60, ME and OMD values were significantly (p<0.001) higher than other silages. Maximum gas production ($A_{gas}$) ranged from 65.7 to 78.1 with alfalfa silage showing the lowest maximum gas production. The results obtained in this study clearly showed that maximum gas production increased with increased percentage of whole-crop maize in the silage mixtures (r = 0.940, p<0.001). It was concluded that ensiling alfalfa with whole-crop maize improved the pH, OMD and ME values. However, trials with animals are required to see how these differences in silage mixtures affect animal performance.

Unroofed Coronary Sinus Atrial Septal Defect Misdiagnosed as Ostium Primum Defect

Semi Ozturk,Gunduz Durmus,Muhsin Kalyoncuoglu,Mustafa Sari,Ozlem Ozbek,Mehmet Can 대한심장학회 2018 Korean Circulation Journal Vol.48 No.1

ON PRIME GAMMA-NEAR-RINGS WITH DERIVATIONS

Uckun, Mustafa,Ozturk, Mehmet Ali,Jun, Young-Bae Korean Mathematical Society 2004 대한수학회논문집 Vol.19 No.3

Conditions for a $\Gamma$-near-ring to be commutative are investigated.

INTUITIONISTIC FUZZY SETS IN GAMMA-SEMIGROUPS

Uckun, Mustafa,Ozturk, Mehmet Ali,Jun, Young-Bae Korean Mathematical Society 2007 대한수학회보 Vol.44 No.2

We consider the intuitionistic fuzzification of the concept of several ${\Gamma}$-ideals in a ${\Gamma}$-semigroup S, and investigate some properties of such ${\Gamma}$-ideals.

The effect of SixNy interlayer on the quality of GaN epitaxial layers grown on Si(111) substrates by MOCVD

Engin Arslan,Mustafa K. Ozturk,Suleyman Ozcelik,Ekmel Ozbay 한국물리학회 2009 Current Applied Physics Vol.9 No.3

In the present paper, the effects of nitridation on the quality of GaN epitaxial films grown on Si(111) substrates by metal–organic chemical vapor phase deposition (MOCVD) are discussed. A series of GaN layers were grown on Si(111) under various conditions and characterized by Nomarski microscopy (NM), atomic force microscopy (AFM), high resolution X-ray diffraction (HRXRD), and room temperature (RT) photoluminescence (PL) measurements. Firstly, we optimized LT-AlN/HT-AlN/Si(111) templates and graded AlGaN intermediate layers thicknesses. In order to prevent stress relaxation, step-graded AlGaN layers were introduced along with a crack-free GaN layer of thickness exceeding 2.2 ㎛. Secondly, the effect of in situ substrate nitridation and the insertion of an SixNy intermediate layer on the GaN crystalline quality was investigated. Our measurements show that the nitridation position greatly influences the surface morphology and PL and XRD spectra of GaN grown atop the SixNy layer. The X-ray diffraction and PL measurements results confirmed that the single-crystalline wurtzite GaN was successfully grown in samples A (without SixNy layer) and B (with SixNy layer on Si(111)). The resulting GaN film surfaces were flat, mirror-like, and crack-free. The full-width-at-half maximum (FWHM) of the X-ray rocking curve for (0002) diffraction from the GaN epilayer of the sample B in ω-scan was 492 arcsec. The PL spectrum at room temperature showed that the GaN epilayer had a light emission at a wavelength of 365 nm with a FWHM of 6.6 nm (33.2 meV). In sample B, the insertion of a SixNy intermediate layer significantly improved the optical and structural properties. In sample C (with SixNy layer on Al0.11Ga0.89N interlayer). The in situ depositing of the, however, we did not obtain any improvements in the optical or structural properties. In the present paper, the effects of nitridation on the quality of GaN epitaxial films grown on Si(111) substrates by metal–organic chemical vapor phase deposition (MOCVD) are discussed. A series of GaN layers were grown on Si(111) under various conditions and characterized by Nomarski microscopy (NM), atomic force microscopy (AFM), high resolution X-ray diffraction (HRXRD), and room temperature (RT) photoluminescence (PL) measurements. Firstly, we optimized LT-AlN/HT-AlN/Si(111) templates and graded AlGaN intermediate layers thicknesses. In order to prevent stress relaxation, step-graded AlGaN layers were introduced along with a crack-free GaN layer of thickness exceeding 2.2 ㎛. Secondly, the effect of in situ substrate nitridation and the insertion of an SixNy intermediate layer on the GaN crystalline quality was investigated. Our measurements show that the nitridation position greatly influences the surface morphology and PL and XRD spectra of GaN grown atop the SixNy layer. The X-ray diffraction and PL measurements results confirmed that the single-crystalline wurtzite GaN was successfully grown in samples A (without SixNy layer) and B (with SixNy layer on Si(111)). The resulting GaN film surfaces were flat, mirror-like, and crack-free. The full-width-at-half maximum (FWHM) of the X-ray rocking curve for (0002) diffraction from the GaN epilayer of the sample B in ω-scan was 492 arcsec. The PL spectrum at room temperature showed that the GaN epilayer had a light emission at a wavelength of 365 nm with a FWHM of 6.6 nm (33.2 meV). In sample B, the insertion of a SixNy intermediate layer significantly improved the optical and structural properties. In sample C (with SixNy layer on Al0.11Ga0.89N interlayer). The in situ depositing of the, however, we did not obtain any improvements in the optical or structural properties.

Apelin Levels in Patients with Coronary Artery Ectasia

Sevket Balta,Cengiz Ozturk,Mustafa Demir,Ali Osman Yildirim 대한심장학회 2016 Korean Circulation Journal Vol.46 No.3

Vibration analysis of cracked frame structures

Ahmed M. Ibrahim,Hasan Ozturk,Mustafa Sabuncu 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.45 No.1

In this study, the effects of crack depth and crack location on the in-plane free vibration of cracked frame structures have been investigated numerically by using the Finite Element Method. For the rectangular cross-section beam, a crack element is developed by using the principles of fracture mechanics. The effects of crack depth and location on the natural frequency of multi-bay and multi-store frame structures are presented in 3D graphs. The comparison between the present work and the results obtained from ANSYS shows a very good agreement.

The effect of single incision laparoscopic cholecystectomy on systemic oxidative stress

Ilhan Ece,Bahadir Ozturk,Huseyin Yilmaz,Serdar Yormaz,Mustafa ?ahin 대한외과학회 2017 Annals of Surgical Treatment and Research(ASRT) Vol.92 No.4

Purpose: Single incision laparoscopic cholecystectomy (SILC) has become a more frequently performed method for benign gallbladder diseases all over the world. The effects of SILC technique on oxidative stress have not been well documented. The aim of this study was to evaluate the effect of laparoscopic cholecystectomy techniques on systemic oxidative stress by using ischemia modified albumin (IMA). Methods: In total, 70 patients who had been diagnosed with benign gallbladder pathology were enrolled for this prospective study. Twenty-one patients underwent SILC and 49 patients underwent laparoscopic cholecystectomy (LC). All operations were performed under a standard anesthesia protocol. Serum IMA levels were analysed before operation, 45 minutes and 24 hours after operation. Results: Demographics and preoperative characteristics of the patients were similiar in each group. The mean duration of operation was 37.5 ± 12.5 and 44.6 ± 14.3 minutes in LC and SILC group, respectively. In both groups, there was no statistically significant difference in hospital stay, operative time, or conversion to open surgery. Operative technique did not effect the 45th minute and 24th hour IMA levels. However, prolonged operative time (>30 minutes) caused an early increase in the level of IMA. Twenty-fourth hour IMA levels were not different. Conclusion: SILC is an effective and safe surgical prosedure for benign gallbladder diseases. Independent of the surgical technique for cholecystectomy, the prolonged operative time could increase the tissue ischemia.