Sürdürülebilir Kalkınma Amaçları
Araştırmacılar(11)
Birim yayınları
26 →- MakaleYalnız künye2026Scopus SJRQ1Hydrogeochemical controls on chromium speciation and potential human health risks in surface waters of an ultramafic mining watershed
Kutlu, Banu; Baydar, Tarık; Yıldırım, Vesile; Konurhan, Zekeriya
Accurate assessment of chromium contamination in mining-influenced watersheds requires distinguishing between the environmentally contrasting Cr(III) and Cr(VI) species, yet environmental monitoring and risk assessments still rely predominantly on total chromium concentrations. This study evaluated whether chromium speciation provides additional information beyond operational total chromium for assessing chromium occurrence and potential human health risks in an ultramafic, mining-influenced watershed. Surface-water samples were collected from 28 sampling stations across the Pülümür and Ovacık regions of the Eastern Anatolia Basin (Türkiye) between March 2025 and February 2026. Chromium speciation was determined using species-specific UV–Visible spectrophotometric methods and integrated with hydrochemical characterization, multivariate statistical analyses, mineralogical investigations (XRD, SEM–EDS, and FTIR), and deterministic and empirical-bootstrap human health risk assessments. Operational total chromium, defined as the sum of separately measured Cr(III) and Cr(VI), ranged from below the detection limit to 578.13 µg L−1. For contextual screening, this calculated value exceeded World Health Organization (WHO) drinking-water guideline for total chromium at 14 stations; however, it was not an independently measured total-Cr concentration. The highest Cr(VI) concentration occurred at a localized hotspot, whereas Cr(III) predominated throughout most of the watershed. Nevertheless, Cr(VI)-based screening thresholds were exceeded at multiple stations under the assumed untreated drinking-water ingestion scenario, indicating that operational total chromium alone did not consistently identify the spatial distribution of Cr(VI)-related potential risk. Screening-level hazard quotient (HQ) estimates were higher for children than for adults; however, direct untreated consumption of the sampled surface waters was not verified. Mining-influenced stations generally exhibited higher chromium concentrations, although the relative contributions of geogenic weathering and mining-related mobilization could not be quantitatively apportioned. Overall, chromium speciation provided additional environmentally and toxicologically relevant information beyond operational total chromium for evaluating chromium mobility and screening-level potential human health risks in this ultramafic watershed.
- MakaleAçık Erişim2025Investigation of the Bioactivity Properties of TiZrCrNb0.3Ta0.07 Medium Entropy Alloy Produced from TNTZ Waste
Say, Yakup; Yayla, Nihal; Güler, Ömer; Güzel, Harun
High entropy alloys (HEAs) and medium entropy alloys (MEAs) have garnered significant attention as alternative materials in various fields due to their superior physical and chemical properties compared to conventional alloys. One of the most promising applications of this innovative material class is in biomaterials. In this study, a bio-medium entropy alloy (BioMEA), TiZrCrNb0.25Ta0.05, was successfully synthesized using non-toxic elements (Ti, Zr, Cr, Nb and Ta) through arc melting of TNTZ alloy waste. The produced BioMEA was comprehensively characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) to analyze its structural and chemical properties. Additionally, the in-vitro degradation, ion release, and bioactivity properties of the alloy were evaluated and compared with those of the conventional TNTZ alloy, with a focus on the effects of heat treatment. The results demonstrated that heat treatment did not cause significant changes in the microstructure of the TiZrCrNb0.25Ta0.05 alloy but led to the formation of intermetallic compounds such as Cr2Zr and Cr2Ta on the surface. Degradation tests revealed an unexpected mass gain across all sample groups after a four-week immersion period due to surface precipitation, surpassing the expected mass loss from degradation. Ion release analyses showed similar behavior between the TiZrCrNb0.25Ta0.05 and TNTZ alloys, with ion release levels in the ppb range, confirming that Ti was released at non-toxic levels. Bioactivity tests identified low lesvels of Ca-P-O deposition on all sample surfaces, with the highest bioactivity observed in the heat-treated TiZrCrNb0.25Ta0.05 sample. Overall, the findings suggest that the TiZrCrNb0.25Ta0.05 alloy has the potential to serve as an alternative biomaterial to the TNTZ alloy, with its bioactivity properties being further enhanced through heat treatment. Further studies are recommended to optimize its bioactivity and evaluate its in-vivo performance for biomedical applications.
- MakaleAçık Erişim2025Scopus SJRQ1One-pot synthesis of quercetin-functionalized silver and copper nanoparticles for enhanced optical, antimicrobial, and computational properties
Aziz, Dara Muhammed; Amin, Alla Ahmed Muhammed; Hassan, Sangar Ali; Özmen, Habibe; INCILI, Gökhan Kursad; Say, Yakup
The emergence of multidrug-resistant bacterial strains has intensified the need for novel antimicrobial agents. Herein, we report a facile one-pot green synthesis of quercetin-stabilized silver (Qn@AgNPs) and copper (Qn@CuNPs) nanoparticles using quercetin as both reductant and capping ligand. The resulting nanocomposites were fully characterized by UV–Vis spectroscopy (surface plasmon resonance peaks at 420 nm for Ag and 580 nm for Cu), FTIR (confirming quercetin–metal coordination), SEM/EDX (spherical particles, and XRD (face-centered cubic Ag and Cu phases). Density functional theory (B3LYP/3-21G) calculations yielded frontier molecular orbital gaps of 0.164 eV for Qn@AgNPs and 0.245 eV for Qn@CuNPs, with corresponding high softness values (12.20 and 8.16 eV⁻¹), indicating enhanced electron-transfer propensity. Molecular electrostatic potential maps revealed increased charge polarization around the metal centers. Antibacterial assays against Escherichia coli and Staphylococcus aureus demonstrated minimum inhibitory concentrations of 2.11 ± 1.22 µg/mL and 4.69 ± 2.68 µg/mL for Qn@AgNPs, and 7.50 ± 0.00 µg/mL and 6.25 ± 0.17 µg/mL for Qn@CuNPs, significantly outperforming free quercetin (188 and 375 µg/mL). In silico docking against the S. epidermidis TcaR regulator (PDB: 1KZN) and E. coli DNA gyrase B (PDB: 1HSK) revealed strong binding affinities (–7.54 to − 10.15 kcal·mol⁻¹), consistent with the observed antimicrobial potency. This integrated experimental–computational study elucidates the mechanistic underpinnings of quercetin-mediated nanoparticle bioactivity and provides a rational framework for designing next-generation flavonoid-functionalized metal nanotherapeutics.
AtıfScopus12WoS11OpenAlex14
İncele - MakaleAçık Erişim2024Effects of Porosity and Boron Reinforcement in AISI 316L Stainless Steel for Biomedical Applications
Aslan, Naim; Aksakal, Bunyamin; Fidan, Ferzan
AISI 316L stainless steel (SS) is one of the most widely used biomaterials in the manufacture of implants and biomaterials. It has advantages over equivalent biomaterials such as low cost, good mechanical properties and biocompatibility. The pores found in porous biomaterials provide mechanical interlock, ensuring strong attachment of the implant to the tissue. In this study, 20%, 30% and 40% by volume of polyvinyl alcohol (PVA) and Boron powder were added into 316L powder to obtain porous SS implant. To investigate the effect of porosity and boron effect on the stainless-steel implant material, the samples produced in PVA and Boron added groups, were sintered at 1180 oC under an argon atmosphere. With the evaporation of PVA in the structure, porous and boron added samples were obtained in two groups. Finally, the samples were subjected to Brinell hardness and compression tests and analyzed by SEM, EDS and XRD. As a result of the hardness tests, the highest values were measured as 37.006, 31.32, 25.28 HB. 39.5, 34.5, 26.2 MPa strengths were measured for 20%, 30% and 40% porous samples respectively.
AtıfOpenAlex1
İncele - MakaleYalnız künye2024Scopus SJRQ1Synthesis, characterization and application of cross-linked functional terpolymer through epoxy group as sorbent for extraction of cadmium from waters and foods: Multivariate optimization
Yılmaz, Ersen; Boztuğ, Ali; Ul Haq, Hameed; Boczkaj, Grzegorz; Altunay, Nail
The purpose of this study was to develop a selective sorbent for cadmium ions (Cd(II)) enrichment in orbital shaker assisted solid phase microextraction (OS-SPME) from different aqueous and food samples. A maleic anhydride-styrene-glycidyl methacrylate (MA-St-GMA) terpolymer was synthesized and characterized in detail. Experimental variables of sample preparation step were optimized using a central composite design (CCD). The final determination step was performed using flame atomic absorption spectroscopy (FAAS). The MA-St-GMA sorbent exhibited a high adsorption capacity (195.9 mg g−1) for the Cd(II) ion. The developed method under optimal conditions provides satisfactory performance and a significant improvement compared to other protocols available in the literature. The linear range and detection limit of the method is 0.1–130 ng mL−1 and 0.03 ng mL−1, respectively. The robustness, intraday/interday precision, selectivity, and accuracy of the method were investigated. To further validate the method, a dedicated series of analysis was performed using certified reference materials (CRMs). This part of the study confirmed the applicability of the method for routine analysis. The OS-SPME-FAAS method was validated using water and food samples. Relative standard deviations and recovery for real-world samples were in ranges 1.7–2.2 % and 95.5–98.5 %, respectively. As a result, the MA-St-GMA sorbent showed that it could quantitatively extract Cd(II) ions from aqueous solution.
AtıfScopus9WoS8OpenAlex9İncele - MakaleYayıncıda açık erişim2024Scopus SJRQ1Investigation of in-vitro bioactivity, electrochemical corrosion, wettability and adhesion properties of bioglass-based coatings modified with Y2O3 and Zr on novel β-type Ti-30Zr-5Mo alloys
Dikici, B.; Say, Y.; Zhao, X.; Niinomi, M.; Szechyńska-Hebda, M.
In this study, the in-vitro bioactivity, electrochemical corrosion resistance, wettability, and adhesion properties of bioglass-based coatings modified with Y2O3 and ZrO2 on Ti-30Zr-5Mo alloy were investigated. The coatings were prepared using the sol-gel method and applied to the alloy substrates through dip-coating. The surface morphology and elemental composition of the coatings were analyzed using SEM/EDS and XRD techniques. Potentiodynamic polarization (PDS) and electrochemical impedance spectroscopy (EIS) were employed to assess the electrochemical behavior of the coatings under in-vitro conditions. Contact angle measurements were conducted to evaluate the wettability of the surfaces. Adhesion strength was measured using tensile testing in accordance with ISO 13779-2 standards. Bioactivity tests were performed by immersing the samples in simulated body fluid (SBF). The results demonstrate that the addition of Y2O3 and ZrO2 improves adhesion strength and corrosion potential, but introducing localized galvanic effects that increase the corrosion current density. Besides, the coatings maintained their structural integrity after the bioactivity tests, and promoted new apatite formation.
AtıfScopus9İncele - MakaleAçık Erişim2023The Effects of Hydroxyapatite on the Corrosion Behaviour of AZ Series Mg Alloys
Say, Yakup
Metallic biomaterials are widely used in the orthopedic and dental applications owing to their advanced biocompatibility and sophisticated mechanical properties. Many studies are carried out to develop new alloys with high specific strength, high corrosion resistance and high biocompatibility as an alternative to present metallic biomaterials. Mg alloys are potential alloys as a biomaterial, especially because they have low density and high biocompatibility. However, especially the corrosion properties of Mg alloys need to be improved. In this study, the surfaces of AZ31, AZ61 and AZ91 alloys, which are promising as biomaterials, were coated with hydroxyapatite with high biocompatibility, and the effects of the bioceramics coatings on corrosion resistance were comprehensively investigated. Crack-free and porous surface morphologies were obtained in all bioceramic coatings and the presence of the coatings on the surfaces was supported by EDS analysis. As a result of the corrosion tests performed in SBF, it was determined that the AZ91 alloy had the highest corrosion resistance among the uncoated samples. The hydroxyapatite bioceramic coatings also improved the corrosion properties of all samples. However, among all samples, the highest corrosion resistance was obtained in the hydroxyapatite coated AZ91 alloy.
AtıfOpenAlex2İncele - MakaleAçık Erişim2023Reclaim of Wrecked Bi-Te Based Materials In Peltier Modules In Thermopower Properties By Mechanical Milling
Yüzüak, Ercüment; Cetin, Mehmet; Yüzüak, Gizem Durak
We thoroughly evaluated the effects of various treatments on the structural and electrical properties of the two as-cast materials, “Sb-doping Bi-Te (p-type)” and “Se-doping Bi-Te (n-type)” which are frequently present in abandoned Peltier modules. To investigate the thermoelectric properties of Bi2Te3-based materials, waste alloys characterized by electrical conductivity using the hot-end method. Alloys were purified by performing arc melting on a water-cooled copper crucible in a vacuum of at least 10-3 mbar, with five times melting sessions to assure homogeneity. A single and long milling period of 144 hours is applied. After the compressing operation, the resulting discs with nanostructures were annealed for an hour at 600 K under vacuum conditions. The discs' structural properties were characterized using X-ray diffraction (XRD) and their surfaces and stoichiometries were determined using scanning electron microscopy with an energy dispersive feature. The Seebeck coefficient of the nanoparticle formed n-type Bi-Te based sample is -35.3 μV.K-1 and p-type Bi-Te based sample is 100 μV.K-1 (15% of mean error margin). It was found that a notable improvement was attained in comparison to the initial state with the addition of nanoparticles.
- MakaleAçık Erişim2023Self-Powered Mechanical Energy Sensor Application of SnO2/Ag and PMMA/ITO Nanocomposites via Triboelectric Effect
Yüzüak, Ercüment; Cetin, Mehmet; Yüzüak, Gizem Durak
The triboelectric nanogenerator is a state-of-the-art device for addressing the growing problem of meeting the world's ever-increasing energy needs by converting mechanical energy into electrical energy. Using the popular semiconductor SnO2 nanostructured thin films as a triboelectric layer over contact regions, as opposed to polymers with lesser performance, increases the output power and life time of nanogenerators. In order to design a triboelectric nanogenerator, deposited thin film SnO2 is used as a friction layer with Ag electrode after heat-treatment at 623 K with a contrary layer of PMMA poly (methyl-methacrylate) with ITO electrode. The structural and electrical properties were analyzed by using scanning electron microscopy (SEM), electro-impedance spectroscopy (EIS) and atomic force microscopy (AFM) measurements. The increased output power of the triboelectric nanogenerator is attributed to the nanoscale PMMA contact charge created by tunneling electrons in the SnO2/Ag nanocomposite thin film layer. Due to its proximity to the PMMA/ITO surface, the SnO2/Ag layer causes electron field emission, and tapping the SnO2/Ag layer may result in electron cloud overlap. Similar to a semiconductor/insulator interface, the Fermi level of SnO2 plays a crucial role in electron transport. The system efficiency stated as a touch detector in a conventional keyboard that generates its own power is revealed in part by an analysis of its operating state up to the 4V.
AtıfOpenAlex2İncele - MakaleAçık Erişim2023Scopus SJRQ2Surface Morphology, Structural, Photovoltaic and Optoelectronic Properties of Diamond Like Carbon-Copper Nanostructures
Kara, Salih; Aslan, Naim; Kurt, Mustafa Şükrü
In this work, we produced Cu doped diomond like carbon films using the magnetron sputtering technique and assessed their structural electrical and optoelectronic characteristics. In the atomic force microscopy (AFM) measurements, it was observed that the surface of the Cu-DLC nanocomposite films was in a granular form and the presence of cluster-like formations. D and G bands, which are the characteristic peaks of the DLC structure, were observed in the Raman spectrum, while Cu and C peaks were observed in the energy dispersive (EDX) spectrum. Photocurrent, photocapacitance, photosensitivity and photoresponse values increased depending on the increasing light intensity. However, the Cu-DLC/n-Si structure displayed low photovoltaic properties. The capacitance and conductance values were considerably affected by the increase in AC signal frequency. The series resistance and the density of the interface states exhibited low frequency dependent behavior which were obtained using the electrical characteristics of the nanocomposite films.
AtıfScopus7WoS7OpenAlex6İncele
Tam Kayıt
| Alan | Değer | Dil |
|---|---|---|
| dc.date.accessioned | 2026-10-28T14:33:31.367311692Z | |
| dc.date.available | 2026-10-28T14:33:31.367311692Z | |
| dc.identifier.uri | https://rdlopen.rawdatalibrary.net/r/munzur/125 | |
| dc.rights | info:eu-repo/semantics/openAccess | |
| dc.title | Makine Bölümü | tr |
| dc.title | Department of Machinery | en |
| organization.identifier.code | munzur-tunceli-makine | |
| organization.unitType | department | |
| rdl.unit.alias | \bmakine bolumu\b | |
| rdl.unit.alias | \bdep\w* (of )?machinery\b |