Browsing by Author "Kara, Selim"
Now showing items 1-15 of 15
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A comparison of fluorescence and UV-visible spectrometry techniques for thermal phase transitions of agarose gels
Arda, Ertan; Kara, Selim; Mergen, Ömer Bahadır; Pekcan, Önder (Springer, 2015)In this study thermoreversible phase transitions of high (HMP) and low (LMP) melting point agarose gels were investigated by using the UV-vis and fluorescence spectroscopy techniques. Pyranine was added to the aqueous ... -
Critical Exponents of Kappa Carrageenan in the Coil-Helix and Helix-Coil Hysteresis Loops
Tarı, Özlem; Kara, Selim; Pekcan, Önder (Taylor & Francis Inc, 2009)The steady-state fluorescence technique was used to study coil-helix (sol-gel) and helix-coil (gel-sol) transitions of the kappa carrageenan-water system with various carrageenan contents. Fluorescence (I) and scattered ... -
Effects of GNP addition on optical properties and band gap energies of PMMA films
Mergen, Ömer Bahadır; Arda, Ertan; Kara, Selim; Pekcan, Önder (Wiley, 2019)In this study the effects of graphene nanoplatelet (GNP) doping on the optical parameters (absorption coefficient alpha and extinction coefficient k) and the optical transition energies (optical band gap and Urbach energies) ... -
Electrical and optical percolations of polystyrene latex-multiwalled carbon nanotube composites
Kara, Selim; Arda, Ertan; Dolastir, Fahrettin; Pekcan, Önder (Academic Press Inc Elsevier Science, 2010)Electrical conductivity and optical transmittance properties of polystyrene (PS)-multiwalled carbon nanotube (MWCNT) composite films were investigated. Composite films were prepared by mixing of various mass fractions of ... -
Electrical optical and fluorescence percolations in P(VAc-co-BuA)/MWCNT composite films
Arda, Ertan; Kara, Selim; Pekcan, Önder (Taylor & Francis Ltd, 2013)Effects of multiwall carbon nanotube (MWCNT) addition on the electrical conductivities optical transparencies and fluorescence emissions of poly(vinyl acetate-co-butyl acrylate) (P(VAc-co-BuA))/MWCNT composite films were ... -
Epidemic models for phase transitions: application to a physical gel
Bilge, Ayşe Hümeyra; Pekcan, Önder; Kara, Selim; Öğrenci, Arif Selçuk (Taylor & Francis Ltd, 2017)Carrageenan gels are characterized by reversible sol-gel and gel-sol transitions under cooling and heating processes and these transitions are approximated by generalized logistic growth curves. We express the transitions ... -
Evaluation of the fractal dimension of polyacrylamide during gelation and swelling
Arda, Ertan; Kara, Selim; Pekcan, Önder; Gülşen, Akın-Evingür (Elsevier, 2021)[Abstract Not Available] -
Fractal Dimensions of kappa-Carrageenan Gels during Gelation and Swelling
Kara, Selim; Arda, Ertan; Pekcan, Önder (Taylor & Francis Inc, 2018)A photon scattering technique for research on the sol-gel and gel-sol transitions in kappa-carrageenan-water systems with various carrageenan contents (CC) was utilized for characterizing the fractal dimensions during ... -
GELATION MECHANISMS
Pekcan, Önder; Kara, Selim (World Scientific Publ Co Pte Ltd, 2012)In this paper, we survey the gelation mechanisms for various polymeric systems which are classified by the type and the strength of the cross-linkages. These are the "irreversible" gels that are cross-linked chemically by ... -
Mathematical Characterization of Thermo-reversible Phase Transitions of Agarose Gels
Öğrenci, Arif Selçuk; Pekcan, Önder; Kara, Selim; Bilge, Ayşe Hümeyra (Taylor & Francis Inc, 2018)The thermal phase transition temperatures of high (HMP) and low melting point (LMP) agarose gels were investigated by using UV-vis spectroscopy techniques. Transmitted light intensities from the gel samples with different ... -
A Quartz Crystal Microbalance (QCM) Study on the Formation of Aqueous ?-Carrageenan-Chitosan Composite Bilayers with NaCl and Graphene Oxide
Kara, Selim; Arda, Ertan; Dolastir, Fahrettin; Pekcan, Onder; Evingur, Gulsen Akin (Taylor & Francis Inc, 2023)Biomaterials and thin biofilms play a fundamental role in the medical, food and pharmaceutical industries. The Quartz crystal microbalance (QCM) measurement technique is one of the attractive techniques which have been ... -
Sorption and Desorption of PVA-Pyrene Chains in and out of Agarose Gel
Kara, Selim; Gacal, Burçin; Tunç, Deniz; Yağcı, Yusuf; Pekcan, Önder (Springer/Plenum Publishers, 2012)In situ steady-state fluorescence (SSF) measurement technique was applied to investigation of pyrene labeled Poly(vinyl alcohol) (PVA-Py) molecules diffusion in and out of agarose gels. Gel samples with four different ... -
Study of Thermal Phase Transitions in Iota Carrageenan Gels via Fluorescence Technique
Tari, Ozlem; Kara, Selim; Pekcan, Önder (Wiley-Blackwell, 2011)The effect of carrageenan concentration on thermal phase transitions of the iota carrageenan gels was investigated by using fluorescence technique. During heating and cooling processes scattered light I(sc) and fluorescence ... -
Thermal Phase Transitions of Agarose in Various Compositions: A Fluorescence Study
Kara, Selim; Arda, Ertan; Dolastir, Fahrettin; Pekcan, Önder (Springer/Plenum Publishers, 2011)The effect of agarose content on thermal phase transitions of the agarose gels was investigated by using Steady State Fluorescence (SSF) method. Scattered light I(sc) and fluorescence intensity I(fl) were monitored against ... -
Thermal Phase Transitions of IOTA Carrageenan in CaCl2 Solutions: A Fluorescence Study
Tari, Ozlem; Kara, Selim; Pekcan, Önder (Taylor & Francis Inc, 2011)The fluorescence technique was employed to study thermal phase transitions of iota (-) carrageenan (IC) in CaCl2 solution. IC gels underwent coil to double helix (c-h) and double helix to dimer (h-d) transitions upon ...