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Fabrication of calcium alginate/gum arabic/egg shell composite microbeads for adsorptive removal of methylene blue dye from aqueous solutions
No full textThis study focuses on the design and application of calcium alginate/gum arabic/eggshell powder composite microbeads (CA/GA/ES10) for the removal of methylene blue dye from aqueous solutions through the adsorption method. The characterization of adsorbents was conducted utilizing ATR-FTIR, SEM, XRD, TGA, and pHpzc. The pHpzc value of CA/GA/ES10 composite microbeads was determined as 5.56. From optimization studies, the contact time, adsorbent dosage, and pH values were determined as 60 min, 0.1 g/50 mL, and ≅ 7, respectively. The adsorption raw data have been utilized in the non-linear Langmuir, Freundlich, Temkin, and Sips models. The maximum adsorption capacity of CA/GA/ES10 composite microbeads, as per the Sips, was determined to be 33.30 mg/g at 298 K. The high correlation coefficients (r2 = 0.9976) and low error functions (χ2 = 0.03) indicate that the non-linear Langmuir is the most appropriate isotherm for the adsorption process. From the Langmuir model, the maximum adsorption capacity was determined as 29.71 mg/g at 298 K. The adsorption process adheres to a non-linear pseudo-second-order (r2 = 0.9999) and Elovich (r2 = 0.9999) models. According to thermodynamic results, the adsorption process occurs exothermic (ΔH∘=-3.77kJ/mol) and spontaneous (ΔG∘=-25.83kJ/molat298K) in nature. The impact of varying salt concentrations on the adsorption process was assessed. According to the salt effect, the removal percentage decreased from 81.12 to 65.15% with the addition of NaCl, and from 81.12 to 58.78% with the addition of CaCl2. The reusability tests show that the composite microbeads created can be used repeatedly for up to 7 cycles. After the 7th cycle, the removal of MB dye decreased from 81.11 to 53.45%. All results showed that the prepared ternary composite microbeads are effective adsorbents for the removal of cationic dye from aqueous solutions
The corrosion resistance effect of nanocomposites containing AuNPs coated onto titanium surfaces
No full textThe purpose of this work was to evaluate the corrosion of commercially pure titanium (cpTi) and polymeric AuNPs nanocomposite thin film coatings on cpTi in vitro in artificial saliva by using different electrochemical tests and surface analysis techniques. Electrochemical impedance spectroscopy (EIS), open circuit potential (OCP) and inductively coupled plasma mass spectrometry (ICP-MS) were associated with FESEM for surface characterization. OCP tests revealed higher potential values for AuNPs-Coated surfaces. Increase of the corrosion resistance for AuNPs-Coated surface was presented by EIS in artificial saliva. Average size of 20 - 30 nm AuNPs in spherical morphology forming agglomerations were observed on AuNPs-Coated surfaces. Compared to cpTi surfaces, a lower release tendency of Ti ions from the AuNPs-Coated Ti surfaces after immersion into artificial saliva was confirmed by ICP-MS. Results suggest that AuNPs-Coated Ti surfaces exhibit an enhanced corrosion resistance
Yabancı dil olarak Türkçe öğretiminde aracılık strateji ve etkinliklerinin kullanımına dair bir durum çalışması
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Nonlinear Aircraft Trim Using A Newton-Raphson Based Whale Optimization Algorithm
No full textDetermining the trim point of an aircraft is essential for designing control law and plays a key role in analyzing flight mechanics and overall performance. This point is obtained by solving a set of nonlinear algebraic equations that define the aircraft's steady-state conditions. Due to various nonlinearities, the trim problem, formulated as a constrained optimization problem, may not be solved or yield multiple solutions. The Newton-Raphson (NR) method, a widely used approach for solving such nonlinear equations, is highly sensitive to initial conditions and may not converge if the starting point is distant from the actual solution. To address this limitation, a hybrid method combining the NR technique with the Whale Optimization Algorithm (WOA), a modern swarm-based meta-heuristic, is proposed and tailored for aircraft trim analysis in this study. A nonlinear aircraft model of an F-16 was developed in the MATLAB/Simulink environment. The model was first trimmed using the NR method and, then, with the proposed hybrid method under different trim conditions. The results show that the hybrid algorithm successfully finds the trim point in cases where the NR method fails to converge to an accurate solution
Poly(azomethine) Based Micelles for Delivery of Caffeic Acid Phenethyl Ester
No full textPoly(azomethine) based micelles have been developed for the delivery of caffeic acid phenethyl ester (CAPE). These micelles, synthesized from a polyazomethine-PEG block copolymer, demonstrate significant potential in drug release systems due to its pH-sensitive biodegradable nature. Characterization through SEM revealed spherical micelles with an average diameter of 135.5 nm. The micelles' drug release behavior was studied at physiological (pH 7.2) and lyso-somal (pH 5.0) pH levels. The findings indicated pH sensitive release of CAPE from the micelle of which only 2.14% of CAPE was released at pH 7.2 while 38.8% of CAPE was released at pH 5.0 after 24 h. In vitro cell viability assays using human-derived fibroblast cells showed that CAPE-loaded micelles exhibited minimal toxicity after 48 hours compared to CAPE and free micelle. These results suggest the potential of polyazomethine-based micelles as efficient carriers for targeted drug delivery for therapeutic purposes
