Malzeme Bilimi ve Nanoteknoloji Mühendisliği Bölümü Koleksiyonu
https://hdl.handle.net/20.500.12573/207
2024-03-29T06:50:21Z
2024-03-29T06:50:21Z
Recovery of Vanadium and Nickel from a High CaCO3 Containing Petroleum Coke Ash by Roasting and Acidic Leaching
Yurtseven, Ozgun
Ibrahim, Ahmedaljaali Ibrahim Idrees
Top, Soner
Kursunoglu, Sait
Altiner, Mahmut
https://hdl.handle.net/20.500.12573/2042
2024-03-28T09:21:31Z
2023-01-01T00:00:00Z
Recovery of Vanadium and Nickel from a High CaCO3 Containing Petroleum Coke Ash by Roasting and Acidic Leaching
Yurtseven, Ozgun; Ibrahim, Ahmedaljaali Ibrahim Idrees; Top, Soner; Kursunoglu, Sait; Altiner, Mahmut
In this study, it was aimed to extract vanadium (V) and nickel (Ni) from a petroleum coke ash (PCA) using a roasting process
without additives, followed by leaching with sulfuric acid (H2SO4). The experiments were designed based on the Taguchi
approach, taking into account the parameters of temperature, acid concentration, time, and solid ratio. Additional leaching
tests were conducted on the non-roasted PCA for comparison, to assess the efect of roasting on the extractions of V and Ni.
The results showed that no extra reducing agent was needed as the PCA contained high levels of CaCO3, which could be
used as a reducing agent during roasting. It was found that roasting was essential for high Ni extractions, but had no strong
efects on V extractions. The Ni extraction was found to be between 13.3 and 80.8% for the non-roasted PCA and between
43.6 and 99.3% for the roasted PCA. The V extraction was between 36 and 97.9% for the non-roasted PCA and between
45.4 and 99.9% for the roasted PCA. The optimal leaching conditions were determined to be a sulfuric acid of 4.5 M, a solid
ratio of 10%, a temperature of 75 °C, and a time of 75 min. In addition, it was determined that the leaching conditions had
a great efect on the oxidation state of vanadium ions, and an increase in the acid concentration led to the formation of V3+
ions (green color) instead of VO2+ ions (blue color) in the pregnant leach solution. The fnal pregnant leach solution containing 1056.50 mg/L V, and 251.85 mg/L Ni was achieved with an extraction yields of>98%. The experimental results were
greatly ftted by the shrinking core model and the activation energy (Ea) for V and Ni was calculated as 3.60 and 4.01 kJ/
mol, indicating that the leaching mechanism can be explained by the difusion control model.
2023-01-01T00:00:00Z
Estimation of cohesion for intact rock materials using regression and soft computing analyses
Köken, Ekin
Strzałkowski P.
Kazmierczak U.
https://hdl.handle.net/20.500.12573/2039
2024-03-28T08:39:34Z
2024-01-01T00:00:00Z
Estimation of cohesion for intact rock materials using regression and soft computing analyses
Köken, Ekin; Strzałkowski P.; Kazmierczak U.
Shear strength parameters such as cohesion (c) and internal friction angle (.) are among the most critical rock properties used in the geotechnical design of most engineering projects. However, the determination of these properties is laboring and requires special equipment. Therefore, this study introduces several predictive models based on regression and artificial intelligence methods to estimate the c of different rock types. For this purpose, a comprehensive literature survey is carried out to collect quantitative data on the shear strength properties of different rock types. Then, regression and soft computing analyses are performed to establish several predictive models based on the collected data. As a result of these analyses, five different predictive models (M1-M5) were established. Based on the performance of the established predictive models, the artificial neural network-based predictive model (model 5, M5) was the most suitable choice for evaluating the c for different rock types. In addition, mathematical expressions behind the M5 model are also presented in this study to allow users to implement it more efficiently. In this regard, the present study can be declared a case study showing the applicability of regression and soft computing analyses to evaluate the c of different rock types. However, the number of datasets used in this study should be increased to get more comprehensive predictive models in future studies. © 2024 Institute of Physics Publishing. All rights reserved.
2024-01-01T00:00:00Z
Rational design of EDTA-incorporated nanoflowers as novel and effective endodontic disinfection against biofilms
Aslan, Tugrul
Dadi, Şeyma
Kafdag, Ozgur
Temur, Nimet
Ildiz, Nilay
Ocsoy, Ismail
Ustun, Yakup
https://hdl.handle.net/20.500.12573/2037
2024-03-28T08:09:15Z
2024-01-01T00:00:00Z
Rational design of EDTA-incorporated nanoflowers as novel and effective endodontic disinfection against biofilms
Aslan, Tugrul; Dadi, Şeyma; Kafdag, Ozgur; Temur, Nimet; Ildiz, Nilay; Ocsoy, Ismail; Ustun, Yakup
The ethylenediaminetetradiacetic acid (EDTA) is one of the most commonly used irrigation solutions. Although EDTA has
a very low antimicrobial property, it is used to remove inorganic part of smear layer in areas of root canal system. Herein,
we developed EDTA-incorporated nanofowers (EDTA NFs), for the frst time, as novel and efective irrigation solution with
quite high antimicrobial property to provide complete disinfection in root canal system. We both systematically elucidated
the formation of the EDTA NFs with various techniques, and their catalytic and antimicrobial activities in the presence of
hydrogen peroxide (H2O2) were documented through intrinsic EDTA property and peroxidase-like activities.
2024-01-01T00:00:00Z
Amorphous carbon nitride (C3N4)
Durandurdu, Murat
https://hdl.handle.net/20.500.12573/2032
2024-03-28T06:47:01Z
2024-01-01T00:00:00Z
Amorphous carbon nitride (C3N4)
Durandurdu, Murat
This detailed investigation employs an ab initio approach to explore the atomic structure and electronic properties of an amorphous carbon nitride (C3N4) model. The model, designed with an exact 3:4 ratio, is based on an
amorphous boron nitride configuration. The study reveals crucial insights into the mean coordination number for
C and N atoms within the amorphous structure. With values of 2.95 for C atoms and 2.21 for N atoms, these
coordination numbers closely resemble those observed in graphite-like crystals. The local structure of the
amorphous network exhibits similarities to the triazine-based graphitic C3N4 crystal and is notably devoid of
homopolar bonds. The estimated band gap for the amorphous C3N4 model is 1.2 eV, representing a significant
reduction compared to the crystal structure, which exhibits a band gap of about 2.93 eV as determined through
GGA+U calculations.
2024-01-01T00:00:00Z