Yazar "Berisha, Avni" seçeneğine göre listele
Listeleniyor 1 - 4 / 4
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Corrosion mitigation performance of disodium EDTA functionalized chitosan biomacromolecule - Experimental and theoretical approach(Elsevier B.V., 2021) Jessima, S. J. Hepziba Magie; Subhashini, S.; Berisha, Avni; Oral, Ayhan; Srikandan, Subramanian SathyDisodium ethylenediaminetetraacetate salt is known for its excellent coordinating properties with the metal ions. The present study deals with the investigation of the prepared Disodium EDTA functionalized chitosan in corrosion inhibition for mild steel in 1 M HCl. The modified chitosan was characterized by spectral studies, thermal analysis, and Zeta potential studies. The corrosion inhibition efficiency (%) was evaluated using the gravimetric method and electrochemical studies. The electrochemical studies included potentiodynamic polarization, linear polarization resistance, and electrochemical impedance methods. The modified chitosan polymer showed an inhibition efficiency of 96.63% for 500 ppm at 303 K. Adsorption process obeyed Langmuir isotherm. Experimental results and theoretical calculations endorsed initial physisorption followed by a chemisorption process. Surface characterization studies supported the formation of a protective film that enabled the inhibition process. Density functional theory, Monte Carlo studies, and molecular dynamics simulation studies show a good agreement with the experimental results. Two-way Analysis of Variance was performed to test the influence of immersion period and inhibitor concentration on the corrosion rate using the statistical software IBM SPSS 20.0. A quartic model was generated as the best fit with the highest R2 value of 0.973. Design Expert software was employed for statistical modeling fit.Öğe Diatomaceous Earth: Characterization, thermal modification, and application(De Gruyter Open, 2021) Reka, Arianit A.; Pavlovski, Blagoj; Fazlija, Emira; Berisha, Avni; Pacarizi, Musaj; Daghmehchi, Maria; Oral, AyhanThe diatomaceous earth (DE), collected from the Mariovo region in North Macedonia, was characterized and thermally modified. The material represents a sedimentary rock of biogenic origin, soft solid that can be easily disintegrated, with white to grayish color, with bulk density of 0.51–0.55 g/cm3, total porosity of 61–63%, and specific gravity of 2.25 g/cm3. The chemical composition is as follows: SiO2, 86.03; Al2O3, 3.01; Fe2O3, 2.89; MnO, 0.06; TiO2, 0.20; CaO, 0.76; MgO, 0.28; K2O, 0.69; Na2O, 0.19; P2O5, 0.15; and loss of ignition, 5.66 (wt%). The mineralogy of the raw DE is characterized by the predominant presence of amorphous phase, followed by crystalline quartz, muscovite, kaolinite, and feldspar. Significant changes in the opal phase are observed in the 1,000–1,200°C temperature region. At 1,100°C, the entire opal underwent solid–solid transition to cristobalite. Further ramp of the temperature (1,100–1,200°C) induced formation of mullite. Scanning electron microscopy (SEM) and transmission electron microscopy depict the presence of micro- and nanostructures with pores varying from 260 to 650 nm. SEM analysis further determined morphological changes in terms of the pore diameters shrinkage to 120–250 nm in comparison to the larger pores found in the initial material. The results from this investigation improve the understanding of mechanism of silica phase transition and the relevant phase alterations that took place in DE upon calcination temperatures from 500 to 1,200°C.Öğe Surface modification of hydroxyapatite with enzyme-catalyzed reaction: Computation-supported experimental studies(Elsevier Science Sa, 2022) Danisman, Merve; Berisha, Avni; Dagdag, Omar; Oral, AyhanSurface modification of the selected particles for different uses (chemical, biological or commercial applications) is a frequently adopted method for industrial and scientific purposes. Thus, the molecules determined for the targeted applications can be attached to particles. However, these methods occur in several steps, at high temperatures, and for long periods of time and require the involvement of chemicals. Chemicals used in the environment and under harsh conditions lead to some restrictions (such as monomer variety and application areas) and cause energy and time loss. Presumably, these problems could be largely avoided by using enzymes, which are natural biocatalysts, in the surface modification of particles. Given this presumption, a surface modification design was devised in this study to modify the hydroxyapatite surface with methacrylic acid using the lipase enzyme. The chemical structures of the particles were characterized through Fourier Transform Infrared and Raman spectroscopy, their thermal behaviors were analyzed with thermogravimetric analysis, and simultaneous molecular modeling studies were conducted to corroborate the experimental studies.Öğe Zeolite 4A as a jammer of bacterial communication in Chromobacterium violaceum and Pseudomonas aeruginosa(Future Medicine Ltd, 2022) Ulusoy, Seyhan; B Akalin, Ramadan; cevikbas, Halime; Berisha, Avni; Oral, Ayhan; Bosgelmez-Tinaz, GulgunAim: To investigate the hypothesis that zeolites interfere with quorum-sensing (QS) systems of Chromobacterium violaceum and Pseudomonas aeruginosa by adsorbing N-acyl homoserine lactone (AHL) signal molecules. Methods: QS inhibition by zeolite 4A was investigated using an AHL-based bioreporter assay. The adsorption of the AHLs was evaluated by performing inductively coupled plasma-optical emission spectroscopy and confirmed by Monte Carlo and molecular dynamic simulations. Results: Zeolite 4A reduced the violacein production in C. violaceum by over 90% and the biofilm formation, elastase and pyocyanin production in P. aeruginosa by 87, 68 and 98%, respectively. Conclusion: Zeolite 4A disrupts the QS systems of C. violaceum and P. aeruginosa by means of adsorbing 3-oxo-C6-AHL and 3-oxo-C12-AHL signaling molecules and can be developed as a novel QS jammer to combat P. aeruginosa-related infections.
