Browsing by Publisher "Kluwer Academic Publishers"
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Item Synthesis, characterization, and thermal degradation of new aromatic poly(azomethine-urethane)s and their polyphenol derivatives(Kluwer Academic Publishers, 2012) Kaya I.; Avci A.A new polyurethane was synthesized by condensation reaction of 2,4-dihydroxy benzaldehyde (DHB) with methylene-di-p-phenyl-diisocyanate (MDI) under argon atmosphere. The synthesized polyurethane was converted to its poly (azomethine urethane) species (MP-2AP, MP-3AP, and MP- 4AP) by graft copolymerization reactions with amino phenols (2-amino phenol, 3-amino phenol, and 4-amino phenol). Obtained poly(azomethine urethane)s (PAMUs) were converted to their polyphenol species (P-MP-2AP, P-MP-3AP, and P-MP-4AP) by oxidative polymerization reaction (OP) using NaOCl as the oxidant. The structures of the obtained compounds were confirmed by FT-IR, UV-vis, 1H-NMR, and 13C-NMR techniques. The molecular weight distribution parameters of the synthesized compounds were determined by the size exclusion chromatography (SEC). The synthesized compounds were also characterized by solubility tests, TGDTA, and DSC analyses. Thermal decomposition steps at various temperatures were clarified by FT-IR analyses of degraded products. Fluorescence measurements were carried out in various concentrated DMF solutions to determine the optimum concentrations to obtain the maximal PL intensities. © 2012 Springer Science+Business Media B.V.Item Fattening performance, carcass and meat quality characteristics of Kivircik male lambs(Kluwer Academic Publishers, 2012) Gökdal Ö.; Atay O.; Eren V.; Demircioğlu S.K.The objective of this study was to determine the fattening performance and carcass and meat quality characteristics of Kivircik twin male lambs. Twelve lambs at approximately 5 months of age were subjected to a finishing diet for 60 days. Average live weight of lambs at the beginning and the end of the fattening were 23. 14 ± 0. 84 and 39. 0 ± 1. 01 kg, respectively. Daily live weight gain and feed conversion efficiency were found as 0. 265 ± 0. 007 and 6. 14 kg, respectively. Hot carcass weight, cold carcass weight, and dressing percentage were 19. 6 ± 0. 6 and 18. 9 ± 0. 6 kg and 48. 1 ± 0. 3%, respectively. Kidney-pelvic fat weight, internal fat weight, and m. longissimus dorsi area were 0. 117 ± 0. 023 and 0. 364 ± 0. 041 kg and 15. 26 ± 0. 70 cm 2 , respectively. The percentages of leg, back loin, forearm, shoulder, neck, flank-chest, kidney-pelvic fat, and internal fat in carcasses of the lambs were found as 34. 1 ± 0. 4%, 19. 6 ± 0. 3%, 21. 0 ± 0. 2%, 7. 0 ± 0. 3%, 10. 5 ± 0. 3%, 7. 2 ± 0. 2%, 1. 3 ± 0. 1%, and 1. 8 ± 0. 1%, respectively. Averages water content, ash, protein content, and fat content of meat samples were 73. 4%, 1. 0%, 19. 5% and 3. 6%, respectively. pH and thiobarbituric acid reactive substances values of meat samples were 5. 55 and 0. 056 ± 0. 017. L*(lightness), a*(redness), and b*(yellowness) values were recorded as 43. 87, 12. 69, and 10. 22, respectively. Thus, we conclude that fattening performance, carcass, and meat quality of Kivircik lambs are satisfactory levels than that of other native breeds. © 2012 Springer Science+Business Media B.V.Item Nonlinear vibrations of axially moving multi-supported strings having non-ideal support conditions(Kluwer Academic Publishers, 2013) Yurddaş A.; Özkaya E.; Boyacı H.In this study, nonlinear vibrations of an axially moving multi-supported string have been investigated. The main difference of this study from the others is in that there are non-ideal supports allowing minimal deflections between ideal supports at both ends of the string. Nonlinear equations of the motion and boundary conditions have been obtained using Hamilton's Principle. Dependence of the equations of motion and boundary conditions on geometry and material of the string have been eliminated by non-dimensionalizing. Method of multiple scales, a perturbation technique, has been employed for solving the equations of motion. Axial velocity has been assumed a harmonically varying function about a constant value. Axially moving string has been investigated in three regions. Vibrations have been examined for three different cases of the velocity variation frequency. Stability has been analyzed and stability boundaries have been established for the principal parametric resonance case. Effects of the non-ideal support conditions on stability boundaries and vibration amplitudes have been investigated. © 2012 Springer Science+Business Media Dordrecht.Item Dynamics of axially accelerating beams with multiple supports(Kluwer Academic Publishers, 2013) Bağdatli S.M.; Özkaya E.; Öz H.R.This study represents the transverse vibrations of an axially accelerating Euler-Bernoulli beam resting on multiple simple supports. This is one of the examples of a system experiencing Coriolis acceleration component that renders such systems gyroscopic. A small harmonic variation with a constant mean value for the axial velocity is assumed in the problem. The immovable supports introduce nonlinear terms to the equations of motion due to stretching of neutral axis. The method of multiple scales is directly applied to the equations of motion obtained for the general case. Natural frequency equations are presented for multiple support case. Principal parametric resonances and combination resonances are discussed. Solvability conditions are presented for different cases. Stability analysis is conducted for the solutions; approximate stable and unstable regions are identified. Some numerical examples are presented to show the effects of axial speed, number of supports, and their locations. © 2013 The Author(s).Item The validation of the turkish version of asthma control test(Kluwer Academic Publishers, 2013) Uysal M.A.; Mungan D.; Yorgancioglu A.; Yildiz F.; Akgun M.; Gemicioglu B.; Turktas H.Introduction: Current guidelines focus more on levels of asthma control than on severity of asthma. The original version of the Asthma Control Test (ACT), a self-administered instrument to determine asthma control levels, was designed for English-speaking patients. More recently, the ACT has been translated into many languages and has been validated for many cultures, but this is the first study to evaluate the Turkish version. Purpose: We aimed to evaluate the reliability, validity, and responsiveness of the Turkish version of the ACT among outpatients with asthma. Method: This multicenter prospective study included 220 asthma patients in outpatient clinics in Turkey. The ACT was completed at admission (Visit 1), after 10 ± 2 days (Visit 2), and at 5 ± 1 weeks (Visit 3). At each visit, physicians assessed patients' asthma control levels. Results: The Turkish version of the ACT showed an internal consistency reliability of 0.84 (Cronbach's alpha). Test-retest reliability was 0.85 in stable patients. There was a significant correlation between the ACT and physicians' assessments at admission (r = 0.68, p < 0.001). The AUC was 0.91, with a sensitivity of 89.06 % and a specificity of 78.26 % for a score of ≤19 for screening "uncontrolled" asthma. A minimally important difference of three points on the ACT was consistent with the GINA physician assessment scores between the baseline and the follow-up visits. Conclusion: The Turkish version of the ACT is a valid and reliable tool for assessing asthma control in patients in outpatient settings. The test may facilitate the designation of asthma patients' symptoms as either controlled or uncontrolled. © 2012 Springer Science+Business Media Dordrecht.Item Development and mechanical behavior of FML/Aluminium foam sandwiches(Kluwer Academic Publishers, 2013) Baştürk S.B.; Tanoğlu M.In this study, the Fiber-Metal Laminates (FMLs) containing glass fiber reinforced polypropylene (GFPP) and aluminum (Al) sheet were consolidated with Al foam cores for preparing the sandwich panels. The aim of this article is the comparison of the flexural properties of FML/Al foam sandwich panels bonded with various surface modification approaches (silane treatment and combination of silane treatment with polypropylene (PP) based film addition). The FML/foam sandwich systems were fabricated by laminating the components in a mould at 200 C under 1.5 MPa pressure. The energy absorbtion capacities and flexural mechanical properties of the prepared sandwich systems were evaluated by mechanical tests. Experiments were performed on samples of varying foam thicknesses (8, 20 and 30 mm). The bonding among the sandwich components were achieved by various surface modification techniques. The Al sheet/Al foam sandwiches were also consolidated by bonding the components with an epoxy adhesive to reveal the effect of GFPP on the flexural performance of the sandwich structures. © 2012 Springer Science+Business Media Dordrecht.Item Synthesis and biodistribution of novel magnetic-poly(HEMA-APH) nanopolymer radiolabeled with iodine-131 and investigation its fate in vivo for cancer therapy(Kluwer Academic Publishers, 2013) Avcibaşi U.; Avcibaşi N.; Akalin H.A.; Ediz M.; Demiroǧlu H.; Gümüşer F.G.; Özçalişkan E.; Türkcan C.; Uygun D.A.; Akgöl S.Herein, we investigated the biological uptake, distribution, and radiopharmaceutical potential of a novel molecule based on 2-hydroxyethyl methacrylate (HEMA) and anilinephtalein (APH) in the metabolism of Albino Wistar rats. In order to achieve this, we synthesized APH using organic synthesis methods and copolymerized APH with HEMA using a common polymerization method, surfactant-free emulsion polymerization. In the presence of Fe3O 4 particles, we obtained a new generation magnetic-nano-scale polymer, magnetic-poly(HEMA-APH). This new molecule was chemically identified and approved by several characterization methods using Fourier transform infrared spectroscopy, scanning electron microscope, energy dispersive X-ray spectroscopy, electron spin resonance, atomic force microscope, and Zeta particle-size analysis. To evaluate the biological activity in live metabolism and anti-cancer potential of mag-poly(HEMA-APH), molecule was radioiodinated by a widely used labeling technique, iodogen method, with a gamma diffuser radionuclide, 131I. Thin-layer radiochromatography experiments demonstrated that 131I binded to nanopolymer with the labeling yield of 90 %. Lipophilicity and stability experiments were conducted to determine the condition of cold and labeled mag-poly(HEMA-APH) in rat blood and lipid medium. Results demonstrated that radioiodinated molecule stayed as an intact complex in rat metabolism for 24 h and experimental lipophilicity was determined as 0.12 ± 0.02. In vivo results obtained by imaging and biological distribution experiments indicated that mag-poly(HEMA-APH) labeled with 131I [131I-mag-poly(HEMA-APH)] highly incorporated into tissues of the uterus, the ovarian, the prostate, and the lungs in rat metabolism. Based on these results, it may be evaluated that novel mag-poly(HEMA-APH) molecule labeled with 131I is a compound which has a significant potential for being used as an anti-cancer agent. Certain results can only be obtained whether this molecule is applied to adenocarcinoma cell models and tumor-bearing animals. © 2013 Springer Science+Business Media Dordrecht.Item Reliability and validity of the Cystic Fibrosis Questionnaire-Revised for children and parents in Turkey: Cross-sectional study(Kluwer Academic Publishers, 2013) Yuksel H.; Yilmaz O.; Dogru D.; Karadag B.; Unal F.; Quittner A.L.Purpose: The purpose of study was to translate Cystic Fibrosis Questionnaire-Revised (CFQ-R) into Turkish for children with cystic fibrosis (CF) and evaluate its reliability and validity. This is the first CF-specific health-related quality of life (HRQOL) measure validated in a Muslim country. Methods: Fifty-one children aged 6-13 years treated at four centers in Turkey and 30 parents participated in this cross-sectional study. Demographic characteristics and disease severity parameters were recorded for all participants. All participants completed the parent or child versions of CFQ-R and KINDL questionnaires at enrollment. Reliability and construct validity analysis were carried out. Results: Both children and parents endorsed a range of responses, with no evidence of floor or ceiling effects. Item-to-total correlations indicated that most items were more highly correlated with their intended scale than competing scales. Good internal consistency was found for majority of child and parent scales. CFQ-R scales correlated significantly with clinical indices of disease severity. Good evidence of convergent validity with a generic HRQOL scale was found. Conclusion: Turkish versions of CFQ-R Child and Parent instruments have demonstrated adequate reliability and validity and can be utilized in clinical trials or integrated into clinical evaluation and follow-up of Turkish children with CF. © 2012 Springer Science+Business Media B.V.Item Predicting Monthly River Flows by Genetic Fuzzy Systems(Kluwer Academic Publishers, 2014) Turan M.E.; Yurdusev M.A.Reliable flow forecasts are key to developing river regulation schemes such as reservoirs. River flow prediction has conventionally been undertaken by physical and black-box models. Several black-box type models have been employed to achieve this end. Of these, genetic fuzzy systems have been used in this study as they have relatively attracted limited attention to date. Genetic-fuzzy systems are the fuzzy systems that have the capability of learning and tuning by Genetic Algorithms. Employing two different fuzzy inference systems, a case study on Gediz river basin has been performed in an attempt to find a suitable genetic fuzzy system for flow prediction. © 2014, Springer Science+Business Media Dordrecht.Item e-core of double sequences(Kluwer Academic Publishers, 2014) Sever Y.; Talo Ö.Boos, Leiger and Zeller [1,2] defined the concept of e-convergence. In this paper we introduce the concepts of e-limit superior and inferior for real double sequences and prove some fundamental properties of e-limit superior and inferior. In addition to these results we define e-core for double sequences. Also, we show that that if A is a nonnegative Ceregular matrix then the e-core of Ax is contained in e-core of x, provided that Ax exists. © 2014, Akadémiai Kiadó, Budapest, Hungary.Item Linear dynamical analysis of fractionally damped beams and rods(Kluwer Academic Publishers, 2014) Dönmez Demir D.; Bildik N.; Sınır B.G.The aim of this study is to develop a general model for beams and rods with fractional derivatives. Fractional time derivatives can represent the damping term in dynamical models of continuous systems. Linear differential operators with spatial derivatives make it possible to generalize a wide range of problems. The method of multiple scales is directly applied to equations of motion. For the approximate solution, the amplitude and phase modulation equations are obtained in terms of the operators. Stability boundaries are derived from the solvability condition. It is shown that a fractional derivative influences the stability boundaries, natural frequencies, and amplitudes of vibrations. The solution procedure may be applied to many problems with linear vibrations of continuous systems. © 2013 Springer Science+Business Media Dordrecht.Item Removal of uranium(VI) from aqueous solutions using nanoporous ZnO prepared with microwave-assisted combustion synthesis(Kluwer Academic Publishers, 2014) Kaynar U.H.; Ayvacıklı M.; Kaynar S.C.; Hiçsönmez U.The adsorption of the uranyl ions from aqueous solutions on the nanoporous ZnO powders has been investigated under different experimental conditions. The adsorption of uranyl on nanoporous ZnO powders were examined as a function of the contact times, pH of the solution, concentration of uranium(VI) and temperature. The ability of this material to remove U(VI) from aqueous solution was followed by a series of Langmuir and Freunlinch adsorption isotherms. The adsorption percent and distribution coefficient for nanoporous ZnO powders were 98.65 % ± 1.05 and 7,304 mL g -1 , respectively. The optimum conditions were found as at pH 5.0, contact time 1 h, at 1/5 Zn 2+ /urea ratio, 50 ppm U(VI) concentration and 303 K. The monomolecular adsorption capacity of nanoporous ZnO powders for U(VI) was found to be 1,111 mg g -1 at 303 K. Using the thermodynamic equilibrium constants obtained at different temperatures, various thermodynamic parameters, such as ΔG, ΔH and ΔS, have been calculated. Thermodynamic parameters (ΔH = 28.1 kJ mol -1 , ΔS = 160.30 J mol -1 K -1 , ΔG = -48.54 kJ mol -1 ) showed the endothermic and spontaneous of the process. The results suggested that nanoporous ZnO powders was suitable as sorbent material for recovery and adsorption of U(VI) ions from aqueous solutions. © 2014 Akadémiai Kiadó, Budapest, Hungary.Item Study of Gamow-Teller transitions in isotopes of titanium within the quasi particle random phase approximation(Kluwer Academic Publishers, 2014) Cakmak S.; Nabi J.-U.; Babacan T.; Selam C.The Gamow-Teller (GT) transition is inarguably one of the most important nuclear weak transitions of the spin-isospin στ type. It has many applications in nuclear and astrophysics. These include, but are not limited to, r-process β-decays, stellar electron captures, neutrino cooling rates, neutrino absorption and inelastic scattering on nuclei. The quasiparticle random phase approximation (QRPA) is an efficient way to generate GT strength distribution. In order to better understand both theoretical systematics and uncertainties, we compare the GT strength distributions, centroid and width calculations for 40-60Ts isotopes, using the pn-QRPA, Pyatov method (PM) and the Schematic model (SM). The pn-QRPA and SM are further sub-divided into three categories in order to highlight the role of particle-particle (pp) force and deformation of the nucleus in the GT strength calculations. In PM, we study only the influence of the pp force in the calculation. We also compare with experimental results and other calculations where available. We found that the inclusion of pp force and deformation significantly improves the performance of SM and pn-QRPA models. Incorporation of pp force leads to pinning down the centroid value in the PM. The calculated GT strength functions using the pn-QRPA (C) and SM (C) models are in reasonable agreement with measured data. © 2014 Springer Science+Business Media Dordrecht.Item The determination of physiological and DNA changes in seedlings of maize (Zea mays L.) seeds exposed to the waters of the Gediz River and copper heavy metal stress(Kluwer Academic Publishers, 2015) Batir M.B.; Candan F.; Buyuk I.; Aras S.In this study, the effects of the heavy metal-polluted waters of the Gediz River, which flow into the Aegean Sea, and different concentrations of copper (Cu) solutions on maize (Zea mays L.) seedlings are investigated with physiological parameters and random amplified polymorphic DNA (RAPD) assay. Results displayed physiologically a significant difference in root and stem length between the control seedlings and the seedlings grown with the waters of the Gediz River. Also, the certain ascending concentrations of copper solution (80, 160, 320, 640, and 1280 ppm) caused a significant decrease in root and stem length of seedlings compared to the control seedlings. As a result of the waters of the Gediz River and copper solution treatment, the changes occurred in RAPD profiles of seedlings observed as variations like increment and/or loss of bands compared with the control seedlings. And these changes were reflected as a decrease in genomic template stability (GTS, changes in RAPD profile) derived by genotoxicity. RAPD band profiles and GTS values showed consistent results with physiological parameter. In conclusion, the study revealed the environmental risk and negative effect of waters of the Gediz River on maize seedlings and the suitability of RAPD assay for the detection of environmental toxicology. © 2015, Springer International Publishing Switzerland.Item Synthesis and characterization of cerium- and gallium-containing borate bioactive glass scaffolds for bone tissue engineering(Kluwer Academic Publishers, 2015) Deliormanlı A.M.Bioactive glasses are widely used in biomedical applications due to their ability to bond to bone and even to soft tissues. In this study, borate based (13-93B3) bioactive glass powders containing up to 5 wt% Ce2O3 and Ga2O3 were prepared by the melt quench technique. Cerium (Ce+3) and gallium (Ga+3) were chosen because of their low toxicity associated with bacteriostatic properties. Bioactive glass scaffolds were fabricated using the polymer foam replication method. In vitro degradation and bioactivity of the scaffolds were evaluated in SBF under static conditions. Results revealed that the cerium- and gallium-containing borate glasses have much lower degradation rates compared to the bare borate glass 13-93B3. In spite of the increased chemical durability, substituted glasses exhibited a good in vitro bioactive response except when the Ce2O3 content was 5 wt%. Taking into account the high in vitro hydroxyapatite forming ability, borate glass scaffolds containing Ce+3 and Ga+3 therapeutic ions are promising candidates for bone tissue engineering applications. © 2015, Springer Science+Business Media New York.Item Zoledronic acid increases cytotoxicity by inducing apoptosis in hormone and docetaxel-resistant prostate cancer cell lines(Kluwer Academic Publishers, 2015) Varol U.; Degirmenci M.; Karaca B.; Atmaca H.; Kisim A.; Uzunoglu S.; Sezgin C.; Sanli U.A.; Uslu R.Our aim was to investigate the possible synergistic/additive cytotoxic and apoptotic effects of combination of docetaxel and zoledronic acid (ZA), in PC-3 hormone-refractory prostate cancer cells (HRPC), as well as their docetaxel-resistant sublines. We established a docetaxel-resistant cell line (PC-3R) from PC-3 prostate cancer cells, by intermittent exposure to increasing concentrations of docetaxel in vitro. We then examined the effect of ZA and docetaxel on cell proliferation in both PC-3 and PC-3R prostate cancer cells. XTT cell proliferation assay was used to assess the cytotoxicity, and DNA fragmentation and caspase 3/7 enzyme activity were measured to verify apoptosis. According to our results, docetaxel and ZA were found to be synergistically cytotoxic and apoptotic in both PC-3 and docetaxel-resistant PC-3R cells, in a dose- and time-dependent manner. Combined treatment with docetaxel and ZA synergistically inhibited PC-3 cell growth in vitro through an enhanced induction of cell death, compared with either agent alone; this result was also evident on PC-3R cells. Moreover, we have also demonstrated that apoptosis was induced in prostate cancer cells exposed to these drugs by a concentration-dependent increase in DNA fragmentation and caspase 3/7 enzyme activity. We concluded that ZA, either with docetaxel or not, might still exert some cytotoxicity even in docetaxel-resistant cells. From the clinical perspective, when the clinician decided to change the treatment in the post-docetaxel setting, continuing or combination with ZA may be an effective therapeutic approach for the treatment of HRPC patients. © 2014, International Society of Oncology and BioMarkers (ISOBM).Item Determination of radon exhalation rate and natural radioactivity levels of building materials used in Istanbul-Turkey(Kluwer Academic Publishers, 2015) Çam Kaynar S.; Özbey E.; Ereeş F.S.Radon concentrations of 63 building materials (block-form and powder-form) used in Istanbul province were measured by using solid state nuclear track detectors (CR-39). Radon exhalation rates for each other were calculated and compared to the literature. The activity concentrations of 40K, 238U and 232Th for 18 powder-form building materials (cement and sand samples) were analyzed by a gamma-ray spectrometer coupled with a NaI(Tl) detector. The activity concentrations of 40K, 238U and 232Th ranged from 2.81 to 638.9 Bqkg−1, 44.68 to 114.26 Bqkg−1 and 2.02 to 34.16 Bqkg−1, respectively. Activity of 238U in sand samples was found as higher than the world average. The activities of 40K, 238U and 232Th are compared with available data from other investigations and the world average value. Radiation hazard indices (radium equivalent activity, external hazard index and indoor hazard index) were calculated by using the activity results. The results are compared to the literature. © 2015, Akadémiai Kiadó, Budapest, Hungary.Item Comparison of the learning curves and frustration level in performing laparoscopic and robotic training skills by experts and novices(Kluwer Academic Publishers, 2015) Passerotti C.C.; Franco F.; Bissoli J.C.C.; Tiseo B.; Oliveira C.M.; Buchalla C.A.O.; Inoue G.N.C.; Sencan A.; Sencan A.; do Pardo R.R.; Nguyen H.T.Introduction: Robotic assistance may provide for distinct technical advantages over conventional laparoscopic technique. The goals of this study were (1) to objectively evaluate the difference in the learning curves by novice and expert surgeons in performing fundamental laparoscopic skills using conventional laparoscopic surgery (CLS) and robotic-assisted laparoscopic surgery (RALS) and (2) to evaluate the surgeons’ frustration level in performing these tasks. Methods: Twelve experienced and 31 novices in laparoscopy were prospectively evaluated in performing three standardized laparoscopic tasks in five consecutive, weekly training sessions. Analysis of the learning curves was based on the magnitude, rate, and quickness in performance improvement. The participant’s frustration and mood were also evaluated during and after every session. Results: For the novice participants, RALS allowed for shorter time to task completion and greater accuracy. However, significant and rapid improvement in performance as measured by magnitude, rate, and quickness at each session was also seen with CLS. For the experienced surgeons, RALS only provided a slight improvement in performance. For all participants, the use of RALS was associated with less number of sessions in which they felt frustrated, less number of frustration episodes during a session, lower frustration score during and after the session, and higher good mood score. Conclusion: The advantages of RALS may be of most benefit when doing more complex tasks and by less experienced surgeons. RALS should not be used as a replacement for CLS but rather in specific situations in which it has the greatest advantages. © 2015, Springer Science+Business Media Dordrecht.Item Nonlinear vibrations of spring-supported axially moving string(Kluwer Academic Publishers, 2015) Kesimli A.; Özkaya E.; Bağdatli S.M.In this study, multi-supported axially moving string is discussed. Supports located at the ends of the string are simple supports. A support located in the middle section owns the features of a spring. String speed is assumed to vary harmonically around an average rate. Hamilton’s principle has been used to figure out the nonlinear equations of motion and boundary conditions. These equations and boundary conditions are dimensionless. Considering the nonlinear effects caused by the string extensions, nonlinear equations of motion are obtained. By using multi-timescaled method, which is one of the perturbation methods, approximate solutions have been found. The first term in the perturbation series causes the linear problem. With the solution of the linear problem, exact natural frequencies have been calculated for different locations of the supports on the middle, various spring coefficients and, with the spring support in the middle of the different location, different spring coefficient and axial speed values. Nonlinear terms on second order add correction terms to the linear problem. Effect of nonlinear terms on the natural frequency has been calculated for various parameters. The cases when the changing frequency of speed is equal to zero, close to zero and close to two times of the natural frequency have been analyzed separately. For each case, the stable and unstable areas in the solutions have been identified by stability analysis. © 2015, Springer Science+Business Media Dordrecht.