Scopus İndeksli Yayınlar Koleksiyonu by Institution Author "Pekcan, Önder"
Now showing items 41-60 of 91
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Gelation of PAAm-PVP composites: A fluorescence study
Evingür, Gülşen Akin; Kaygusuz, Hakan; Erim, F. Bedia; Pekcan, Önder (World Scientific, 2014)Hybrid hydrogels are a new class of composite materials. Polyacrylamide (PAAm) hydrogels are mainly produced by free radical crosslinking copolymerization (FCC) of AAm in the presence of N N'-methylene bis (acrylamide) ... -
Group behaviour in physical chemical and biological systems
Saçlıoğlu, Cihan; Pekcan, Önder; Nanjundiah, Vidyanand (Indıan Acad Scıences, 2014)Groups exhibit properties that either are not perceived to exist or perhaps cannot exist at the individual level. Such 'emergent' properties depend on how individuals interact both among themselves and with their surroundings. ... -
In situ steady state fluorescence (SSF) technique to study drying of PAAm hydrogels made of various cross-linker contents
Evingür, Gülşen Akın; Aktas, Demet Kaya; Pekcan, Önder (Elsevier Science, 2009)Drying experiments of polyacrylamide (PAAm) gels were performed using steady-state fluorescence (SSF) spectrometer. Pyranine (P) was introduced as a fluorescence probe and intensity of P from various crosslinker content ... -
Investigation of Drying of Poly(N-isoproplacrylamide-co-acrylamide) by Fluorescence Technique
Evingür, Gülşen Akin; Pekcan, Önder (Wiley-Blackwell, 2013)The steady-state fluorescence technique was performed on drying of various molar percentages of poly(N-isopropylacrylamide-co- acrylamide) [poly(NIPA-co-AAc)] to elucidate the mechanism of temperature-induced phase separation ... -
Investigation of PSt-MWCNT concentration on epoxyacrylate photopolymerization and conductivity of polymer films
Doğruyol, Zekeriya; Temel, Gökhan; Doğruyol, Sevnur Keskin; Pekcan, Önder; Arsu, Nergis (Elsevier Science SA, 2013)Photopolymerization kinetics and conductivity changes of epoxyacrylate composites for various loading modified PSt-MWCNT weight fractions changing from 0.0025 to 0.2 wt.% were evaluated by performing photo differential ... -
Kinetic models for the dynamical behavior of polyacrylamide (PAAm)-kappa-carrageenan (kappa C) composite gels
Evingür, Gülşen Akın; Pekcan, Önder (Springer, 2015)A fluorescence method was employed for studying the drying and swelling of PAAm-kappa C composite gels which were formed from acrylamide (AAm) and N N'- methylenebisacrylamide (BIS) with various kappa-carrageenan (kappa ... -
A mathematical characterization of the gel point in sol-gel transition
Bilge, Ayşe Hümeyra; Pekcan, Önder (IOP Publishing Ltd, 2015)We model the sol-gel transition in terms of Susceptible-Infected-Removed (SIR) and Susceptible-Exposed-Infected-Removed (SEIR) models and compare with experimental results. We show, numerically, that the "gel point" described ... -
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 MATHEMATICAL DESCRIPTION OF THE CRITICAL POINT IN PHASE TRANSITIONS
Bilge, Ayşe Hümeyra; Pekcan, Önder (World Scientific Publ Co Pte Ltd, 2013)Let y(x) be a smooth sigmoidal curve, y((n)) be its nth derivative and {x(m,i)} and {x(a,i)}, i = 1, 2, ... , be the set of points where respectively the derivatives of odd and even order reach their extreme values. We ... -
Mathematical models for phase transitions in biogels
Bilge, Ayşe Hümeyra; Öğrenci, Arif Selçuk; Pekcan, Önder (World Scientific Publ Co Pte Ltd, 2019)It has been shown that reversible and irreversible phase transitions of biogels can be represented by epidemic models. The irreversible chemical sol-gel transitions are modeled by the Susceptible-Exposed-Infected-Removed ... -
Measurement of oxygen diffusion in PS/PNIPAM films using fluorescence quenching
Yargı, Önder; Pekcan, Önder; Uğur, Şaziye (Taylor & Francis Ltd, 2015)The diffusion of oxygen into pyrene labelled polystyrene (PS) latex/poly(N-isopropylacrylamide) (PNIPAM) composite films (PS/PNIPAM) was studied based on PS content with the use of fluorescence quenching method. Fluorescence ... -
Mechanical properties of graphene oxide-polyacrylamide composites before and after swelling in water
Evingür, Gülşen Akin; Pekcan, Önder (Springer, 2018)Polyacrylamide (PAAm) hydrogels have been proposed for use as promising biomaterials in biomedical and tissue engineering but their poor mechanical and water-retention properties have hindered their development. Graphene ... -
Modelling of Swelling by the Fluorescence Technique in Kappa Carrageenan Gels
Tari, Özlem; Pekcan, Önder (Amer Inst Physics, 2011)Kappa (-kappa) carrageenan gels prepared with various carrageenan concentrations in pure water were completely dried and then swelled in water vapor. Steady state fluorescence measurements were performed using a spectrometer ... -
The modifier effects of chymotrypsin and trypsin enzymes on fluorescence lifetime distribution of "N-(1-pyrenyl)maleimide-bovine serum albumin" complex
Özyiğit, İbrahim Ethem; Karakuş, Emine; Pekcan, Önder (Pergamon-Elsevier Science LTD, 2016)Chymotrypsin and trypsin are the well known proteolytic enzymes, both of which are synthesized in the pancreas as their precursors the inactive forms; chymotrypsinogen and trypsinogen and then are released into the duodenum ... -
Monitoring of dynamical processes in PAAm-MWNTs composites by fluorescence method
Evingür, Gülşen Akın; Pekcan, Önder (Taylor & Francis Ltd, 2012)Polyacrylamide (PAAm)-multi walled carbon nanotube (MWNT) composites were prepared by free radical cross-linking copolymerization in water. Ammonium persulfate and NN'-methylenebis (acrylamide) (BIS) were used as a free ... -
Monitoring the gelation of polyacrylamide-sodium alginate composite by fluorescence technique
Evingür, Gülşen Akin; Tezcan, Filiz; Erim, F. Bedia; Pekcan, Önder (Taylor & Francis Ltd, 2012)Polyacrylamide (PAAm)-sodium alginate (SA) composite was prepared with different amounts of SA varying in the range between 0.06% and 2% (w/v). The PAAm-SA composite was characterized by the steady-state fluorescence ... -
Optical energy band gap of PAAm-GO composites
Evingür, Gülşen Akin; Pekcan, Önder (Elsevier Science, 2018)Graphene oxide (GO) can be used as an electron acceptor for polymers. The generation of the exciton in such materials is intimately related to the optical band gap. Polyacrylamide (PAAm) - graphene oxide (GO) composites ... -
Oxygen Diffusion into Multiwalled Carbon Nanotube Doped Polystrene Latex Films Using Fluorescence Technique
Yargı, Önder; Ugur, Saziye; Pekcan, Önder (Springer/Plenum Publishers, 2013)This study examines the oxygen diffusion into polystyrene (PS) latex/multiwalled carbon nanotube (MWNT) nanocomposite films (PS/MWNT) consisting of various amounts of MWNT via steady state fluorescence technique (SSF). ... -
Oxygen Diffusion into Polymer-Clay Composite Films as a Function of Clay Content and Temperature
Uğur, Şaziye; Yargı, Önder; Elaissari, Abdelhamid; Pekcan, Önder (Wiley-VCH Verlag GmbH, 2009)A simple fluorescence technique is proposed for the measurement of the diffusion coefficient of oxygen into polystyrene-clay composite films as a function of clay content and temperature. The composite films were prepared ... -
Oxygen diffusion into polystyrene-bentonite films
Uğur, Şaziye; Yargı, Önder; Pekcan, Önder (Elsevier, 2009)A simple fluorescence technique is proposed for the measurement of the diffusion coefficient of oxygen into polystyrene-clay composite films. The composite films were prepared from the mixture of surfactant-free pyrene ...