Browsing by Author "Aydin, S."

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Open Access
Artifcial intelligence–based approaches to evaluate and optimize phytoremediation potential of in vitro regenerated aquatic macrophyte Ceratophyllum demersum L.
(2023-01-06) Aasim, M.; Ali, Seyid Amjad; Aydin, S.; Bakhsh, A.; Sogukpinar, C.; Karatas, M.; Khawar, K.M.; Aydin, M.E.
Water bodies or aquatic ecosystem are susceptible to heavy metal accumulation and can adversely afect the environment and human health especially in underdeveloped nations. Phytoremediation techniques of water bodies using aquatic plants or macrophytes are well established and are recognized as eco-friendly world over. Phytoremediation of heavy metals and other pollutants in aquatic environments can be achieved by using Ceratophyllum demersum L. — a well-known foating macrophyte. In vitro regenerated plants of C. demersum (7.5 g/L) were exposed to 24, 72, and 120 h to 0, 0.5, 1.0, 2.0, and 4.0 mg/L of cadmium (CdSO4·8H2O) in water. Results revealed signifcantly diferent relationship in terms of Cd in water, Cd uptake by plants, bioconcentration factor (BCF), and Cd removal (%) from water. The study showed that Cd uptake by plants and BCF values increased signifcantly with exposure time. The highest BCF value (3776.50) was recorded for plant samples exposed to 2 mg/L Cd for 72 h. Application of all Cd concentrations and various exposure duration yielded Cd removal (%) between the ranges of 93.8 and 98.7%. These results were predicted through artifcial intelligence–based models, namely, random forest (RF), extreme gradient boosting (XGBoost), and multilayer perceptron (MLP). The tested models predicted the results accurately, and the attained results were further validated via three diferent performance metrics. The optimal regression coefcient (R2) for the models was recorded as 0.7970 (Cd water, mg/L), 0.9661 (Cd plants, mg/kg), 0.9797 bioconcentration factor (BCF), and 0.9996 (Cd removal, %), respectively. These achieved results suggest that in vitro regenerated C. demersum can be efcaciously used for phytoremediation of Cd-contaminated aquatic environments. Likewise, the proposed modeling of phytoremediation studies can further be employed more comprehensively in future studies aimed at data prediction and optimization.
Open Access
TL/OSL studies of Li2B4O7:Cu dosimetric phosphors
(2013) Aydin, T.; Demirtaş H.; Aydin, S.
Dosimetric phosphors of Cu-doped lithium tetraborate (Li2B 4O7:Cu) were produced using a sintering technique in a laboratory environment and characterized using Scanning Electron Microscopy (SEM) and X-ray Diffractometry (XRD). The thermoluminescence (TL) and optically stimulated luminescence (OSL) properties of powdered (Li2B 4O7) phosphor doped with copper at different concentrations (0.020-0.025 wt %) were studied. The Cu-doped Li 2B4O7 phosphor material has two dominant TL glow peaks, and the maximum TL responses of the peaks are at 115 C and 243 C in the range of 0 C-310 C. The TL response of the Cu-doped lithium tetraborate is approximately 900 times more sensitive than undoped lithium tetraborate. The TL and OSL signal intensities increase as the beta radiation doses increase up to approximately 150.00 Gy and 76.50 Gy, respectively. The OSL dose-response curve is linear up to a dose range of 12.00 Gy for Cu-doped Li2B 4O7 dosimetric phosphors. The time-dependent fading behavior of the Cu-doped lithium tetraborate was found to be quite stable over long time durations. In addition, the repeatability of the OSL dose measurements were determined to be 2/3 lower compared to the TL measurements. The reproducibility of the OSL measurements was approximately 5%. Based on the TL and OSL results, the prepared phosphors can be used to measure beta doses ranging from 10 μGy to 150.00 Gy and 76.50 Gy, respectively, by using the TL and OSL techniques, with confidence limits of approximately 7% and 3-4%, respectively. © 2013 Elsevier Ltd. All rights reserved.