Browsing by Author "Pekcan,O."

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Energy Needs for Drying of Paam-Κc Composites Prepared With Various Κc Contents
(European Polymer Federation, 2011) Pekcan,O.; Evingür,G.A.
Various polyacrylamide (PAAm) - Kappa Carrageenan (κC) composite gels were prepared from acrylamide (AAm), N,N'-methylenebisacrylamide (BIS) and different κC contents by free radical crosslinking copolymerization in water. Pyranine (P) was introduced as a fluorescence probe, and scattered light, Isc, and fluorescence intensities, I, from these gels were monitored during drying at different temperature. The fluorescence intensity of pyranine increased as drying time is increased for all samples. The behavior of I was quantified using the Stern-Volmer equation with moving boundary diffusion model. Desorption coefficient, D increased as temperature was increased for a given κC content. Supporting gravimetrical and volumetric experiments were also carried out during drying of PAAm-κC composite gels. The energy, ΔE values were measured for the drying processes for each kC content gel by using fluorescence, gravimetrical and volumetric methods, respectively. It is understood that ΔE values increase by increasing κC content, indicating that energy needs for the drying of high κC content gel is larger than low κC content gel.
Citation - Scopus: 1
CHAOTIC – DETERMINISTIC OR RANDOM NATURE OF EARTHQUAKES: A PHASE SPACE ANALYSIS
(Symmetrion, 2023) Pekcan,O.; Arsan,T.
Using the phase space approach, time series analysis of high EV1 and low EV2 intense two different earthquakes that occurred at the nearly same precise spot, at different times, and were measured with the same sensor of a broadband station were studied. Time series data of strong, large (EV1) and weak, small (EV2) two earthquake events were analyzed by dividing them into three different regions. Fractal dimensions of the EV1 and EV2 were produced using the box-counting algorithm for east-west (BHE), north-south (BHN), and vertical (BHZ) components. The small, weak earthquake, EV2, created a larger fractal dimension in phase space by implying its random nature in all regions. However, EV1 is a strong, large earthquake that presents deterministic oscillatory behavior at a long-time region. Oscillatory behavior can be named surface wave. EV2 exhibits weak, high-frequency ground oscillations similar to fibrillation before and after the earthquake in the long-term areas. © 2023, Symmetrion. All rights reserved.