Molecular alignment relaxation in polymer optical fibers for sensing applications

A systematic study of annealing behavior of drawn PMMA fibers was performed. Annealing dynamics were investigated under different environmental conditions by fiber longitudinal shrinkage monitoring. The shrinkage process was found to follow a stretched exponential decay function revealing the heterogeneous nature of the underlying molecular dynamics. The complex dependence of the fiber shrinkage on initial degree of molecular alignment in the fiber, annealing time and temperature was investigated and interpreted. Moreover, humidity was shown to have a profound effect on the annealing process, which was not recognized previously. Annealing was also shown to have considerable effect on the fiber mechanical properties associated with the relaxation of molecular alignment in the fiber. The consequences of fiber annealing for the climatic stability of certain polymer optical fiber-based sensors are discussed, emphasizing the importance of fiber controlled pre-annealing with respect to the foreseeable operating conditions

Bragg gratings inscription using PMMA polymer optical fibers drawn from preforms with specific thermal pre-treatment

In this work, fiber Bragg gratings (FBGs) are inscribed in various undoped poly(methyl methacrylate) (PMMA) polymer optical fibres (POFs) using different types of UV lasers and inscription time and their temperature and strain sensitivities are investigated. The polymer optical fiber Bragg gratings (POFBGs) were inscribed using two UV lasers: a continuous UV HeCd @325 nm laser and a pulsed UV KrF @248 nm laser. The PMMA POFs drawn from a preform without specific thermal pre-treatment need more inscription time than the fibers drawn from a preform that has been pre-annealed at 80ºC for 2 weeks. Using both UV lasers, for the latter fiber less than half the inscription time is needed compared with a commercial undoped PMMA POF and other homemade POFs, where the preforms have not had a well-defined thermal pre-treatment. The effect on a POF from a preform that has been annealed prior to drawing is different as previously shown in the literature, where these POFs are much less sensitive to thermal treatment. Also, a proper polymerization process plays a key role as will be discussed. These results indicate the impact of preform thermal pre-treatment as well as polymerization process before the PMMA POFs drawing, which can be an essential characteristic in view of developing POF sensors technology

The solution of the time-fractional diffusion equation by the generalized differential transform method

WOS: 000317262100032In the present paper, a general recurrence relation for determining the solutions of the time-fractional diffusion equation is obtained with the generalized differential transform method. The obtained relation will help us to solve time-fractional diffusion equations with various external forces and initial conditions. Four illustrative examples are given. (C) 2011 Elsevier Ltd. All rights reserved.Scientific Research Projects Unit of Ahi Evran UniversityAhi Evran University [FBA-11-17]This work was supported by the Scientific Research Projects Unit of Ahi Evran University under the project number of FBA-11-17

A STUDY ON THE k-GENERALIZATIONS OF SOME KNOWN FUNCTIONS AND FRACTIONAL OPERATORS

WOS: 000416773700004In this paper, we first draw attention to the relationships between the original definitions and their k-generalizations of some known functions and fractional operators. Using these relationships, we not only easily reacquired the results which can be found in the existing literature for the k generalizations, but also show how to achieve new results with the help of known properties of the original functions and operators. We conclude our paper by observing that, since the definitions of k-generalizations are closely related to the original definitions (that is, the k = 1 case), most of the formulas and results for the k = 1 case can be translated rather trivially and simply by appropriate parameter and notational changes to hold true for the corresponding k-case.Ahi Evran University Scientific Research Projects Coordination Unit [FEF.A3.16.035]The authors would like to thank to Prof. H. M. Srivastava for his valuable comments and suggestions that helped us to improve this article. This work was supported by the Ahi Evran University Scientific Research Projects Coordination Unit. Project Number: FEF.A3.16.035

An extension of Caputo fractional derivative operator and its applications

WOS: 000386871300014In this paper, an extension of Caputo fractional derivative operator is introduced, and the extended fractional derivatives of some elementary functions are calculated. At the same time, extensions of some hypergeometric functions and their integral representations are presented by using the extended fractional derivative operator, linear and bilinear generating relations for extended hypergeometric functions are obtained, and Mellin transforms of some extended fractional derivatives are also determined. (C) 2016 All rights reserved.Ahi Evran University Scientific Research Projects Coordination UnitAhi Evran University [PYO-FEN.4001.14.014]This work was partly presented on September 3-7, 2012 at 1st International Eurasian Conference on Mathematical Sciences and Applications IECMSA-2012 at Prishtine-KOSOVO. This work was supported by Ahi Evran University Scientific Research Projects Coordination Unit. Project Number: PYO-FEN.4001.14.014

GENERALIZED M-SERIES AND ITS CERTAIN PROPERTIES

Kiymaz, I. Onur/0000-0003-2375-0202WOS: 000497987700007In this paper, we introduce a generalization of M-series by using the extended beta function. We also obtain its certain properties such as integral representations, derivative formulas, fractional integral and derivative formulas, Laplace, Mellin and Beta transforms.Ahi Evran University Scientific Research Projects Coordination UnitAhi Evran University [FEF.D1.16.001]This work were presented in the Third International Conference on Computational Mathematics and Engineering Sciences (CMES-2018) which held on May 04-06, 2018 in Girne, Turkish Republic of Northern Cyprus. This work was also supported by Ahi Evran University Scientific Research Projects Coordination Unit with Project Number FEF.D1.16.001

Case Report of Unilateral Silent Sinus Syndrome with Variable Enophthalmos

A 35-year-old man applied to our clinic complaining that one of his eyes occasionally appeared smaller than the other for the last 6 months. The patient had no history of previous trauma or periorbital surgery. Ocular examination revealed 20/20 vision in both eyes and his pupillary and motility examinations were normal. The right eye showed 1mm hypoglobus and a deep superior sulcus. Considering possible silent sinus syndrome, CT scan was ordered and the diagnosis was established by visualizing an occlusion in the right osteomeatal aperture of the maxillary sinus with typical bending of the floor towards the sinus. The patient had undergone endoscopic sinus surgery through the right nasal meatus and the purulent material was drained through maxillary antrostomy. No intra-or postoperative complications were observed, and patient complaints and symptoms resolved immediately after the surgery. (Turk J Ophthalmol 2015; 45: 125-127

Vascular Landmark Classification in Retinal Images Using Fuzzy RBF

21st Signal Processing and Communications Applications Conference (SIU) -- APR 24-26, 2013 -- CYPRUSWOS: 000325005300222This paper suggests the use of radial based neural networks for classification of the landmark points from retina vessels in the retinal vascular images to diagnose the disease in the diabetic retinopathy patients and to track the periodic differences in retinal vessel images. In the suggested method, Gold Standard images from DRIVE database are used. The performance of landmark detection by the suggested method shows that the method can be used as an algorithm for registration of retinal images