Browsing by Author "Aydin, G"

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    Effect of Quenching and Tempering Temperature on Corrosion Behavior of Boron Steels in 3.5 wt.% NaCl Solution
    Aydin, G; Yazici, A
    This study was carried out to examine the impact of austenitization and tempering temperatures on the corrosion characteristics of boron steels. Boron steel samples were austenitized at 850 degrees C, 900 degrees C, and 950 degrees C, and then quenched in environmental water. After quenching, the samples were tempered at 150 degrees C, 300 degrees C, and 450 degrees C for 30 minutes to prepare specimens. The corrosion characteristics of quenched and tempered boron steels in a 3.5 wt.% NaCl solution were examined using Tafel extrapolation method. Significant statistical differences have been observed between the tested boron steels in terms of corrosion rate. Changing C concentration affected the corrosion rates of boron steels after their immersion into a 3.5 wt% NaCl solution and increasing C content generally accelerated the corrosion rate. A poor correlation has been found between average ferrite grain size and corrosion rate under the examined heat treatment conditions for tested boron steels.
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    Effect of quenching and tempering temperature on the tensile properties of low alloyed boron steel
    Aydin, G; Yazici, A
    The effect of quenching and tempering temperature on the tensile properties and the yield strength ratio of 30MnB5, 27MnCrB5, and 34MnB5 boron steel have been investigated. Quenching (Q) and tempering (T) temperatures varied in the range of 850 to 950 degrees C and 150 to 450 degrees C, respectively. The mechanical properties of quenched and tempered steel were examined with the application of the tensile test and hardness testing. The microstructure was characterized using optical microscopy and X-ray diffraction. The increase in Q & T temperatures resulted in a decrease in the ultimate tensile strength (UTS), yield strength (YS) and break strength (BS) values and an increase in the yield strength ratio. The tempering temperature was found to be more effective on the UTS, YS and BS values than was the austenitizing temperature. It was noted that the effect of tempering temperature is greater on the ultimate tensile than on the yield strength for the investigated low alloyed boron steel. The effect of the tempering temperature on the elongation to fracture is also greater than the effect on the uniform elongation. The yield strength ratio showed a tendency to increase with increasing tempering temperatures. It was raised considerably by increasing the tempering temperatures from 300 to 450 degrees C, while it remained at a similar level between 150 and 300 degrees C. The ratio of ultimate tensile strength and mean hardness decreased with increasing tempering temperatures for the tested varieties of steel. Increasing tempering temperature leads to an increase in yield strength ratio and a total
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    Quality of life and related variables in patients with ankylosing spondylitis
    Bodur, H; Ataman, S; Rezvani, A; Bugdayci, DS; Çevik, R; Birtane, M; Akinci, A; Altay, Z; Günaydin, R; Yener, M; Koçyigit, H; Duruöz, T; Yazgan, P; Çakar, E; Aydin, G; Hepgüler, S; Altan, L; Kirnap, M; Ölmez, N; Soydemir, R; Kozanoglu, E; Bal, A; Sivrioglu, K; Karkucak, M; Günendi, Z
    To evaluate quality of life (QoL) and related variables in patients with ankylosing spondylitis (AS), a chronic inflammatory disease of the spine. Nine-hundred and sixty-two patients with AS from the Turkish League Against Rheumatism AS Registry, who fulfilled the modified New York criteria, were enrolled. The patients were evaluated using the Assessment of SpondyloArthritis International Society core outcome domains including Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), fatigue (BASDAI-question 1), pain (last week/spine/due to AS), Bath Ankylosing Spondylitis Functional Index (BASFI), Bath Ankylosing Spondylitis Metrology Index (BASMI), Bath Ankylosing Spondylitis Radiology Index (BASRI), Maastricht Ankylosing Spondylitis Enthesitis Score (MASES) and two QoL questionnaires (the disease-specific ASQoL and generic the Short Form-36 [SF-36]). The mean ASQoL score was 7.1 +/- A 5.7. SF-36 subscales of general health, physical role and bodily pain had the poorest scores. ASQoL was strongly correlated with disease duration, BASDAI, fatigue, BASFI, BASMI, BASRI, MASES, pain and SF-36 subscales (P < 0.001). SF-36 subscales were also strongly correlated with BASDAI and BASFI. Advanced educational status and regular exercise habits positively affected QoL, while smoking negatively affected QoL. In patients with AS, the most significant variables associated with QoL were BASDAI, BASFI, fatigue and pain. ASQoL was noted to be a short, rapid and simple patient-reported outcome (PRO) instrument and strongly correlated with SF-36 subscales.
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    Description of the registry of patients with ankylosing spondylitis in Turkey: TRASD-IP
    Bodur, H; Ataman, S; Bugdayci, DS; Rezvani, A; Nas, K; Uzunca, K; Emlakcioglu, E; Karatepe, AG; Durmuus, B; Sezgin, M; Ayhan, F; Yazgan, P; Duruöoz, T; Yener, M; Gürgan, A; Kirnap, M; Çakar, E; Altan, L; Soydemir, R; Çapkin, E; Tekeoglu, I; Aydin, G; Günendi, Z; Nacir, B; Salli, A; Öztürk, C; Memis, A; Turan, Y; Kozanoglu, E; Sivrioglu, K
    A web-based application patient follow-up program was developed to create a registry of patients with ankylosing spondylitis (AS) by the Turkiye Romatizma Arastirma Savas Dernegi (TRASD) AS Study Group. This study describes the methodological background and patient characteristics. The patient follow-up program is a web-based questionnaire, which contains sections on socio-demographic data, anamnesis, personal and family history, systemic and musculoskeletal examination, laboratory and imaging data and treatment. Between October 1, 2007 and February 28, 2009, 1,381 patients from 41 centers were included in the registry (1,038 males [75.2%]; mean age 39.5 +/- A 10.7 years). Mean disease duration was 12.1 +/- A 8.5 years, and mean time from initial symptom to diagnosis was 5 +/- A 6.8 years (median 2 years). HLA-B27 positivity was detected in 73.7% of 262 patients tested. Manifestations of extraarticular involvement were anterior uveitis (13.2%), psoriasis and other skin and mucous membrane lesions (6%) and inflammatory bowel disease (3.8%). The prevalence of peripheral arthritis was 11.2%. In 51.7% of patients, the Bath AS Disease Activity Index was a parts per thousand yen4. But since our patients consisted of the ones with more severe disease who referred to the tertiary centers and needed a regular follow-up, they may not represent the general AS population. Disease-modifying anti-rheumatic drugs were being used by 41.9% of patients, with 16.4% using anti-TNF agents. TRASD-IP (Izlem Programi: Follow-up program) is the first AS registry in Turkey. Such databases are very useful and provide a basis for data collection from large numbers of subjects. TRASD-IP gives information on the clinical and demographic profiles of patients, and the efficacy and safety of anti-TNF drugs, examines the impact on quality of life, and provides real-life data that may be used in cost-effectiveness analyses.
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    Correlations among enthesitis, clinical, radiographic and quality of life parameters in patients with ankylosing spondylitis
    Rezvani, A; Bodur, H; Ataman, S; Kaya, T; Bugdayci, DS; Demir, SE; Koçyigit, H; Altan, L; Ugurlu, H; Kirnap, M; Gür, A; Kozanoglu, E; Akinci, A; Tekeoglu, I; Sahin, G; Bal, A; Sivrioglu, K; Yazgan, P; Aydin, G; Hepgüler, S; Ölmez, N; Sendur, ÖF; Yener, M; Altay, Z; Ayhan, F; Durmus, O; Duruöz, MT; Günendi, Z; Nacir, B; Öken, Ö; Toktas, H; Delialioglu, SÜ; Evcik, D; Sertpoyraz, FM
    Objectives. To investigate the relationship between enthesitis and disease activity, functional status, fatigue, joint mobility, radiological damage, laboratory parameter and quality of life in patients with ankylosing spondylitis (AS). Methods. A total of 421 patients with AS (323 male and 98 female) who were included in the Turkish League Against Rheumatism Registry were enrolled in the study. The Bath AS Disease Activity Index (BASDAI), fatigue, the Bath AS Functional Index (BASFI), the Bath AS Metrology Index (BASMI), the Maastricht AS Enthesitis Score (MASES), AS quality of life (ASQoL), the Bath AS Radiology Index (BASRI) and erythrocyte sedimentation rate (ESR) were evaluated. Results. Enthesitis was detected in 27.3% of patients. There were positive correlations between MASES and BASDAI, BASFI and fatigue (p < 0.05). MASES was not correlated with BASRI, BASMI, ASQoL and ESR. The mean MASES score was 1.1 +/- 2.4. The most frequent regions of enthesopathies were right iliac crest, spinous process of L5 and proximal to the insertion of left achilles tendon, respectively. Conclusions. Enthesitis was found to be associated with higher disease activity, higher fatigue, worse functional status and lower disease duration. As enthesitis was correlated with BASDAI, we conclude that enthesitis can reflect the disease activity in patients with AS.