Browsing by Author "Yavuz M."
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Item Determination of the optimum conditions for dissolution of magnesite with H2SO4 solutions(2006) Abali Y.; Çopur M.; Yavuz M.Basic data on leaching of magnesite (MgCO3) with sulphuric acid are of interest from the point of view of the industrial process for obtaining pure MgSO4. The Taguchi method was used to determine the optimum conditions for the dissolution of magnesite in H2SO4 solutions. The experiments were performed within the ranges mentioned herein i.e. 20-65°C for reaction temperature, 0.5/100-10/100 g/mL for solid-to-liquid ratio, 0.2-5 M for acid concentration, 5-60 min for reaction time and 150-750 rpm for stirring speed. The optimum conditions for these factors were found to be 65°C, 5/100 g/mL, 2 M, 60 min and 300 rpm, respectively. Under these conditions, the dissolution mass fraction of MgCO 3 in H2SO4 solutions were w = 96.32%.Item Item Improving the mechanical, physical, thermal, and morphological properties of isotactic polypropylene with dialkylperoxide(PRINTS PUBLICATIONS PVT LTD, 2013) Şirin K.; Yavuz M.; Çanli M.; Avci A.; Doǧan F.In this study, the influence of the visbreaking agent (DAP) on mechanical, physical, thermal and morphological properties of PP has been studied. For this reason, isotactic polypropylene (PP) matrices containing 0.01, 0.02, 0.04, 0.06, 0.08, and 0.1 wt% of dialkylperoxide [2, 5dimethyl-2,5-di (tert-butyl peroxy)-hexane, (DAP)] were prepared by using a single-screw extruder. As a result of DAP addition, the crystallinity ratio of the PP matrices has changed between 2.67-7.80%. Mechanical properties of the matrices have been improved. Particularly, the mechanical tests of PP have given Interesting results when compounded with 0.02 wt.% dialkyl peroxide. The microstructure of isotactic polypropylene matrix was investigated by scanning electron microscopy (SEM). From SEM analysis, it was observed that the surface disorder increased by the increasing amount of DAP. Thermal analyses of the matrices were investigated using thermogravimetry in dynamic nitrogen atmosphere at different heating rates. The Flynn-WallOzawa (FWO), Kissinger and master plots method were employed to determine the kinetic model and kinetic parameters of the decomposition processes under non-isothermal conditions. It was found that the thermal stability, activation energy and thermal decomposition processes were all changed by increasing amount of DAP in the matrix structure. © MD Publications Pvt. Ltd.Item Mechanical properties of polypropylene (PP)+high-density polyethylene (HDPE) binary blends: Non-isothermal degradation kinetics of PP+HDPE (80/20) Blends(2013) Şirin K.; Doǧan F.; Çanli M.; Yavuz M.In this study, the mechanical properties and non-isothermal degradation kinetics of polypropylene (PP), high-density polyethylene (HDPE) with dilauroyl peroxide and their blends in different mixture ratios were investigated. The effects of adding dilauroyl peroxide (0-0.20wt%) on the mechanical and thermal properties of PP+HDPE blends have been studied. On the other hand, the kinetics of the thermal degradation and thermal oxidative degradation of PP+HDPE (80/20wt%) blends were studied in different atmospheres, to analyze their thermal stability. The kinetic and thermodynamic parameters such as the activation energy, Ea, the pre-exponential factor, A, the reaction order, n, the entropy change, the enthalpy change, and the free energies of activated complex related to PP, HDPE, and blend systems were calculated by means of the several methods on the basis of the single heating rate. A computer program was developed for automatically processing the data to estimate the reaction parameters by using different models. Most appropriate method was determined for each decomposition step according to the least-squares linear regression. © 2013 John Wiley & Sons, Ltd.Item Investigation of the element diffusion in friction welded X53CrMnNiN219 and X45CrSi93 steels(Carl Hanser Verlag, 2014) Uzkut M.; Un̈lü B.S.; Yavuz M.; Akdag M.In this study, high alloyed steel bars with a diameter of 12.30 mm made up of 1.4871 (X53CrMnNiN219) and 1.4718 (X45CrSi93) steels were used as experimental material for friction welding. Metallographie and X-ray diffraction investigations as well as microprobe sampling were performed on the samples. Mechanical orientation of particles caused by plastic deformation and carbide scattering has been observed. The diffusion behaviour has been investigated for the elements Cr, Ni, Mn, and Si, respectively. The existence of (Cr,Fe) 7C3 carbides in the welding region was also observed. © Carl Hanser Vpriai' GmhH & Co. KG.Item Influence of dilauroyl peroxide on mechanical and thermal properties of different polypropylene matrices(Polymer Society of Korea, 2015) Şirin K.; Yavuz M.; Çanli M.In this study, the influence of dilauroyl peroxide on mechanical and thermal properties of different polypropylene (PP) matrices was investigated. Polypropylene matrices, different molecular weight isotactic PP containing 0.01, 0.02, 0.04, 0.06, 0.08, and 0.1 wt% of dilauroyl peroxide (DLP) were prepared by using a single-screw extruder. The effect of the visbreaking agent (DLP) on mechanical, physical, thermal and morphological properties of different molecular weight PP had been studied. Mechanical properties (tensile strength at break point, at yield and elongation at break point), melt flow index (MFI), scanning electron microscope (SEM) and differential scanning calorimetric (DSC) analyses of these matrices were examined. Melting (Tm) and crystallization (Tc) temperatures, crystallinity ratio (%) and enthalpies were determined. The microstructure of isotactic polypropylene matrix was investigated by scanning electron microscopy (SEM). From SEM analysis, it was observed that the surface disorder increased by the increasing amount of DLP. As a result of DSC analyses, the crystallinity ratio of the PP matrices has varied between 1.64-7.27%. Mechanical properties of the matrices have been improved. Particularly, the mechanical tests of PP have given interesting results when compounded with 0.06-0.08 wt% dilauroyl peroxide (DLP). Mechanical properties and thermal decomposition processes were all changed by increasing the amount of DLP in the matrix structure. © 2015 The Polymer Society of Korea. All rights reserved.Item Re-examining the characteristics of pediatric multiple sclerosis in the era of antibody-associated demyelinating syndromes(W.B. Saunders Ltd, 2022) Yılmaz Ü.; Gücüyener K.; Yavuz M.; Öncel İ.; Canpolat M.; Saltık S.; Ünver O.; Çıtak Kurt A.N.; Tosun A.; Yılmaz S.; Özgör B.; Erol İ.; Öztoprak Ü.; Elitez D.A.; Direk M.Ç.; Bodur M.; Teber S.; Anlar B.; Aykol D.; Yıldız E.P.; Yarar C.; Kara B.; Haspolat; İncecik F.; Kutluk G.; Dilber C.; Dundar N.O.; Tan H.; Demir E.; Dursun B.D.; Dilek T.D.; Türkdoğan D.; Yalnızoğlu D.; Akbaş S.; Güleç A.; Yılmaz D.; Ayanoğlu M.; Kanmaz S.; Güngör S.; Öztürk G.; Besen; Haliloğlu G.; Karaca N.B.; Öztürk S.; Yüksel D.; Gürkaş E.; Oktay S.; Serin H.M.; Karadağ M.; Hakkı Akbeyaz İ.; Yiş U.; Polat B.G.; Okan M.S.; Bektaş Ö.; Orgun L.T.; Günbey C.; Per H.; Gültutan P.; Öztürk S.B.; Aksoy E.; Akyüz G.; Tekgül H.; Kürekçi F.; Kurul A.S.H.; Çarman K.B.; Alikılıç D.; Duman Ö.; Kömür M.; Yıldırım M.; Alıcı N.; Gümüş H.; Polat M.; Konuşkan B.; Güngör O.; Mert G.G.; Edizer S.; Mıhçı F.; Öztürk S.T.; Toker R.T.; Arslan M.; Şahin S.; Gencpinar P.; Yıldırım E.; Yüksel E.; Ekici A.; Deniz A.; Yayici Köken Ö.; Okuyaz Ç.; Süt N.Y.; Atasoy E.; Solmaz İ.; Yetkin M.F.; Bilgin N.; Atasever A.K.; Tekin H.G.; Dokurel İ.; Özçelik A.; Aksoy A.; Türköz A.N.; Cavusoglu D.; Özkan M.; Tekin E.; Şahin T.U.; Ünalp A.; Koç H.; Sarıgeçili E.; Sarıtaş S.; Ayça S.; Kayılıoğlu H.; Şenoğlu M.Ç.; Kamaşak T.; Asadova N.; Keskin F.; Karaoğlu P.; İpek R.; Acer H.Background: The discovery of anti-myelin oligodendrocyte glycoprotein (MOG)-IgG and anti-aquaporin 4 (AQP4)-IgG and the observation on certain patients previously diagnosed with multiple sclerosis (MS) actually have an antibody-mediated disease mandated re-evaluation of pediatric MS series. Aim: To describe the characteristics of recent pediatric MS cases by age groups and compare with the cohort established before 2015. Method: Data of pediatric MS patients diagnosed between 2015 and 2021 were collected from 44 pediatric neurology centers across Türkiye. Clinical and paraclinical features were compared between patients with disease onset before 12 years (earlier onset) and ≥12 years (later onset) as well as between our current (2015–2021) and previous (<2015) cohorts. Results: A total of 634 children (456 girls) were enrolled, 89 (14%) were of earlier onset. The earlier-onset group had lower female/male ratio, more frequent initial diagnosis of acute disseminated encephalomyelitis (ADEM), more frequent brainstem symptoms, longer interval between the first two attacks, less frequent spinal cord involvement on magnetic resonance imaging (MRI), and lower prevalence of cerebrospinal fluid (CSF)-restricted oligoclonal bands (OCBs). The earlier-onset group was less likely to respond to initial disease-modifying treatments. Compared to our previous cohort, the current series had fewer patients with onset <12 years, initial presentation with ADEM-like features, brainstem or cerebellar symptoms, seizures, and spinal lesions on MRI. The female/male ratio, the frequency of sensorial symptoms, and CSF-restricted OCBs were higher than reported in our previous cohort. Conclusion: Pediatric MS starting before 12 years was less common than reported previously, likely due to exclusion of patients with antibody-mediated diseases. The results underline the importance of antibody testing and indicate pediatric MS may be a more homogeneous disorder and more similar to adult-onset MS than previously thought. © 2022 European Paediatric Neurology SocietyItem Corrigendum to “Re-examining the characteristics of pediatric multiple sclerosis in the era of antibody-associated demyelinating syndromes” [Europ. J. Paediatr. Neurol. 41 (2022) 8–18 doi.org/10.1016/j.ejpn.2022.08.006, (S1090379822001246), (10.1016/j.ejpn.2022.08.006)](W.B. Saunders Ltd, 2024) Yılmaz Ü.; Gücüyener K.; Yavuz M.; Ibrahim Oncel; Canpolat M.; Saltık S.; Ünver O.; Çıtak Kurt A.N.; Tosun A.; Yılmaz S.; Özgör B.; Ilknur Erol; Öztoprak Ü.; Elitez D.A.; Çobanoğulları Direk M.; Bodur M.; Teber S.; Anlar B.; Erol İ.; Aykol D.; Direk M.Ç.; Yıldız E.P.; Yarar C.; Kara B.; Haspolat; İncecik F.; Kutluk G.; Dilber C.; Dundar N.O.; Tan H.; Öncel İ.; Demir E.; Dursun B.D.; Dilek T.D.; Türkdoğan D.; Yalnızoğlu D.; Akbaş S.; Güleç A.; Yılmaz D.; Ayanoğlu M.; Kanmaz S.; Güngör S.; Öztürk G.; Besen; Haliloğlu G.; Karaca N.B.; Öztürk S.; Yüksel D.; Gürkaş E.; Oktay S.; Serin H.M.; Karadağ M.; Akbeyaz İ.H.; Yiş U.; Polat B.G.; Okan M.S.; Bektaş Ö.; Orgun L.T.; Günbey C.; Per H.; Gültutan P.; Öztürk S.B.; Aksoy E.; Akyüz G.; Tekgül H.; Kürekçi F.; Hız Kurul A.S.; Çarman K.B.; Alikılıç D.; Duman Ö.; Kömür M.; Yıldırım M.; Alıcı N.; Gümüş H.; Polat M.; Konuşkan B.; Güngör O.; Mert G.G.; Edizer S.; Mıhçı F.; Öztürk S.T.; Toker R.T.; Arslan M.; Şahin S.; Gencpinar P.; Yıldırım E.; Yüksel E.; Ekici A.; Deniz A.; Köken Ö.Y.; Okuyaz Ç.; Süt N.Y.; Atasoy E.; Solmaz İ.; Yetkin M.F.; Bilgin N.; Atasever A.K.; Tekin H.G.; Dokurel İ.; Özçelik A.; Aksoy A.; Türköz A.N.; Cavusoglu D.; Özkan M.; Tekin E.; Şahin T.U.; Ünalp A.; Koç H.; Sarıgeçili E.; Sarıtaş S.; Ayça S.; Kayılıoğlu H.; Şenoğlu M.Ç.; Kamaşak T.; Asadova N.; Keskin F.; Karaoğlu P.; İpek R.; Acer H.The authors would like to apologise for any inconvenience caused. © 2024 European Paediatric Neurology SocietyItem Push and Pull Factors of Why Medical Students Want to Leave Türkiye: A Countrywide Multicenter Study(Routledge, 2024) Eser E.; Cil E.; Sen Gundogan N.E.; Col M.; Yildirim Ozturk E.N.; Thomas D.T.; Sunter A.T.; Arslan H.N.; Citil R.; Onder Y.; Picakciefe M.; Dede B.; Demirel C.; Aydin N.; Caglayan C.; Aker A.A.; Borlu A.; Durmus H.; Can G.; Siddikoglu E.; Sumer E.H.; Uygun T.; Alkoy S.; Aktas Aycan K.; Koruk İ.; Kuzan R.; Demir L.S.; Hacilar E.; Sari H.; Kilinc Z.; Onal O.; Dogan E.; Emek M.; Terzioglu R.; Yapici G.; Erdal D.; Eser S.; Ayhan Akman E.; Kosan Z.; Yilmaz S.; Ayoglu F.N.; Acikgoz B.; Musal B.; Suner A.F.; Erdogan A.; Cilburunoglu İ.; Saygun M.; Daymaz D.; Arslantas D.; Onsuz M.F.; Beyhun N.E.; Ustundag M.G.; Ekuklu G.; Ozder Tas F.; Abacigil F.; Oncu S.; Hıdıroğlu S.; Ozaydin A.N.; Pirincci E.; Bulut I.; Tozun M.; Eskiocak M.; Gunel P.; Torun S.D.; Yavuz M.; Hasde M.; Camur D.; Gunes G.; Kurt B.; Guler Baysoy N.; Bakirci N.; Demir F.; Catak B.; Ozyurda F.; Turan M.Phenomenon: Physician immigration from other countries is increasing as developed countries continue to be desirable destinations for physicians; however, the determinants of Turkish physicians’ migration decisions are still unclear. Despite its wide coverage in the media and among physicians in Türkiye, and being the subject of much debate, there is insufficient data to justify this attention. With this study, we aimed to investigate the tendency of senior medical students in Türkiye to pursue their professional careers abroad and its related factors. Approach: This cross-sectional study involved 9881 senior medical students from 39 different medical schools in Türkiye in 2022. Besides participants’ migration decision, we evaluated the push and pull factors related to working, social environment and lifestyle in Türkiye and abroad, medical school education inadequacy, and personal insufficiencies, as well as the socioeconomic variables that may affect the decision to migrate abroad. The analyses were carried out with a participation rate of at least 50%. Findings: Of the medical students, 70.7% had emigration intentions. Approximately 60% of those want to stay abroad permanently, and 61.5% of them took initiatives such as learning a foreign language abroad (54.5%) and taking relevant exams (18.9%). Those who wanted to work in the field of Research & Development were 1.37 (95% CI: 1.22–1.54) times more likely to emigrate. The push factor that was related to emigration intention was the “working conditions in the country” (OR: 1.89, 95% CI: 1.56–2.28) whereas the “social environment/lifestyle abroad” was the mere pull factor for the tendency of emigration (OR: 1.73, 95% CI: 1.45–2.06). In addition, the quality problem in medical schools also had a significant impact on students’ decisions (OR: 2.20, 95% CI: 1.83–2.65). Insights: Although the percentage of those who want to emigrate “definitely” was at the same level as in the other developing countries, the tendency to migrate “permanently” was higher in Türkiye. Improving working conditions in the country and increasing the quality of medical faculties seem vital in preventing the migration of physicians. © 2023 Taylor & Francis Group, LLC.