Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Şenay, Volkan(7)
- Pat, Suat(6)
- Özen, Soner(6)
- Korkmaz, Şadan(5)
- Bayram, Sinan(3)
- Geçici, Birol(2)
- Kundakçı, Mutlu(2)
- Sarıtaş, Sevda(2)
- Elbir Abca, Tuğba(1)
- Gençcelep, Hüseyin(1)
- Kara, Adem(1)
- Korkmaz, Šadan(1)
- Merhan Muğlu, Günay(1)
- Muğlu, Günay Merhan(1)
- Salari, Maryam Abdolahpour(1)
- Turgut, Erdal(1)
- Yıldırım, Muhammet(1)
- Šenay, Volkan(1)
Yayınlar
- MakaleAçık Erişim2026Scopus SJRQ2Physical, chemical and thermal characterization of bacterial nanocellulose produced using sugar beet molasses by Komagataeibacter sp. SB2569
Kara, Adem; Bayram, Sinan
Bacterial nanocellulose (BNC) is a biopolymer synthesized by bacteria utilizing various carbon sources. The biocompatible and biodegradable nature of BNC offers considerable advantages for its application in fields such as medicine, biomedical engineering, cosmetics, food, nanocomposites, and organoelectronics. Nevertheless, the high production costs necessitate the development of more cost-effective and efficient BNC production methodologies. This study aimed to produce BNC utilizing cost-effective sugar beet molasses. To achieve this, bacteria isolated from various vinegar samples were assessed, revealing that the BNC production potential of these isolates ranged from 2.09 to 3.21 g L⁻1. The 16S rDNA gene of the strain with the highest BNC yield was amplified and sequenced, and it was subsequently deposited in the GenBank database as Komagataeibacter sp. SB2569, with the accession number PV231799.1. XRD analysis revealed characteristic diffraction peaks at 14.8°, 16.5°, 22.6°, and 34.5°, confirming the cellulose 1β crystalline structure and high crystallinity of the synthesized BNC. FTIR analysis exhibited characteristic absorption bandsthat, confirming the presence of β-1,4-glycosidic linkages and the cellulose I structure of BNC. TGA analysis showed an initial weight loss of ~ 5% between 0–100 °C, a major degradation of ~ 75% occurring at 220–350 °C with a maximum decomposition rate at 343 °C, and a residual mass of approximately 10–20% remaining above 600 °C. The findings indicate that the Komagataeibacter sp. SB2569 strain holds significant potential for BNC production using low-cost carbon sources.
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İncele - MakaleAçık Erişim2026Scopus SJRQ1Corn Oil Oleogel With γ-Oryzanol/β-Sitosterol: Structural, Thermal, Textural, and Oxidative Characterization
Elbir Abca, Tuğba; Gençcelep, Hüseyin
In this study, a corn oil oleogel was prepared using γ-oryzanol and β-sitosterol to create a “healthier solid fat-like” structure aimed at reducing saturated and trans fat consumption. To prepare six different oleogels, a γ-oryzanol:β-sitosterol mixture (60:40) was added to corn oil at concentrations ranging from 6% to 15%. The samples were comprehensively evaluated in terms of oil-binding capacity and color; thermal behavior (including melting/crystallization properties); crystal structure; texture properties (hardness, stickiness, cohesion, and spreadability); molecular interactions and oxidative stability. The findings showed that all formulations had high oil binding capacity and that increasing the oleogelator concentration had a limited effect on oil binding. It has been determined that concentration plays an important role in the product's thermal resistance. Results show that as the oleogelator ratio increases, the structure becomes stronger and more durable; the melting behavior in thermal measurements shifts to higher temperatures. Crystal structure analyses support the formation of an oleogel network, while FTIR results indicate that the structure is formed predominantly through physical interactions. Consequently, it has been demonstrated that corn oil can acquire solid fat-like functional properties through this approach and offers a viable option for developing healthier fat formulations, particularly in spreadable products, margarine, and bakery fats.
- MakaleYalnız künye2025Scopus SJRQ1Evaluation of the optical, structural, and morphological characteristics of a Sn-doped α-Fe2O3 thin film fabricated using RF and DC magnetron Co-sputtering technique
Salari, Maryam Abdolahpour; Şenay, Volkan; Muğlu, Günay Merhan; Sarıtaş, Sevda; Kundakçı, Mutlu
In this research, a Sn-doped hematite (α-Fe2O3) thin film on a glass substrate was synthesized using DC and RF magnetron sputtering techniques, and the physical features of the film were analyzed in detail. This study, conducted to investigate the effects of Sn doping on the hematite structure, evaluated the optical and morphological attributes of the thin film using advanced characterization techniques such as UV–VIS spectroscopy, Raman spectroscopy, XRD, SEM, EDS, and AFM. The optical band gap was determined from absorption measurement and calculated to be 2.12 eV. Raman spectroscopy results revealed various characteristic peaks between 100 cm−1 and 1500 cm−1. A strong (214) diffraction peak confirms the enhanced hematite phase formation in the thin film. The crystallite size of the Sn-doped thin film, calculated via Scherrer's formula, is 20 nm. SEM images showed that the thin film exhibited a smooth and homogeneous surface morphology on the glass substrate. According to the EDS results, the atomic doping ratio of Sn in Fe2O3 is 2.84 %. Additionally, AFM analysis confirmed that the Sn-doped α-Fe2O3 thin film had a smooth surface, as indicated by a low RMS (Root Mean Square) roughness value of 8.11 nm. These properties suggest that the thin film could be suitable for optoelectronic applications. The study emphasizes the potential of Sn-doped α-Fe2O3 thin films, particularly for optoelectronic and photocatalytic devices, and underscores the need for further investigation of these materials. Furthermore, it was concluded that these materials should be considered in a broader context for their potential use in various technological applications.
AtıfScopus23WoS22OpenAlex25İncele - MakaleAçık Erişim2024Scopus SJRQ2Optical, structural, morphological, and gas sensing properties of Mg-doped α-Fe2O3 thin films deposited by RF and DC magnetron Co-sputtering technique
Sarıtaş, Sevda; Merhan Muğlu, Günay; Turgut, Erdal; Kundakçı, Mutlu; Yıldırım, Muhammet; Şenay, Volkan
In this research, Mg-doped hematite (α-Fe2O3) thin films with different Mg-doping concentrations were synthesized on glass substrates using the direct current (DC) and radio frequency (RF) magnetron co-sputtering technique, and the changes of some physical properties due to the concentration of the dopant were investigated. The optical, structural, morphological, and elemental properties of the obtained Mg-doped α-Fe2O3 thin films were determined by X-ray diffraction (XRD) analysis, UV–Vis spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), dispersive X-ray spectroscopy and atomic force microscopy (AFM). XRD analysis revealed that the investigated thin films have a rhombohedral crystal structure. The deposition of films at different DC sputtering voltages caused significant variations in stoichiometry and nanostructure. The thin films' band gap energy values were estimated based on absorption measurements, and results ranged from 2.15 eV to 2.69 eV. Raman peaks were observed between 218 cm−1 and 1305 cm−1. The thin films exhibit uniform surface morphology throughout the substrate according to the SEM images. The low RMS roughness values obtained from AFM images showed that the surfaces of Mg:Fe2O3 thin films are smooth. The Mg-doped α-Fe2O3 thin film doped by 150 W DC voltage exhibited a good gas-sensing response at 300 °C. A remarkably quick response/recovery time was achieved.
AtıfScopus19WoS13OpenAlex20İncele - MakaleAçık Erişim2022Scopus SJRQ3A comparative characterization study between fungal and bacterial eumelanin pigments
Bayram, Sinan
Melanins are the most common and the most enigmatic natural pigments in the nature that found in many different taxa group such as bacteria, yeasts, fungi, insects, plants, reptiles, birds and mammals. These biological macromolecules are highly complex cross-linked, heterogeneous biopolymers and composed of polymerized phenolic and/or indolic compounds. Recently, interest in these ubiquitous biopolymers has been increasing considerably in many different areas such as medicine, pharmacology, cosmetics, organic electronic and optoelectronics because of their versatile properties. In this study, four different extracellular eumelanin pigments (two bacterial eumelanins and two fungal eumelanins) were characterized by different spectrometric techniques such as FT-IR, XRD, NMR and UV-vis. In XRD analyzes, purified fungal and bacterial eumelanin pigments were characterized by giving a wide peak at about 22o with an angle of 2θ. Furthermore, in the 1 H NMR spectra of these biopolymers, it was observed that all pigments have signals in both aromatic and aliphatic regions. In addition to these analyzes, nanostructures of these biopolymers were characterized using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Finally, eumelanin pigment producer microorganisms were molecularly characterized. 16 S rDNA and 18 S rDNA sequence analysis results of these microorganisms (Streptomyces fulvissimus MPPS4, Streptomyces xiamenensis MPPS6, Aspergillus niger MPPF16 and Aspergillus terreus MPPF25) were deposited in NCBI GenBank® database with accession number MT825594, MT973972, MW652652 and MW652653 respectively.
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İncele - MakaleAçık Erişim2021Scopus SJRQ2Production, purification, and characterization of Streptomyces sp. strain MPPS2 extracellular pyomelanin pigment
Bayram, Sinan
Melanins are natural pigments widely distributed in nature from bacteria to humans. These complex, negatively charged, amorphous, high molecular mass natural biopolymers have many different bioactive properties such as antimicrobial, antiviral, antioxidant, liver protective effects, etc. In this study, some chemical and physical properties of the purified extracellular pyomelanin pigment were investigated via XRD (X-ray diffraction), FT-IR (Fourier transform infrared), and 1H NMR (Nuclear magnetic resonance). Additionally, the melanin pigment producer Streptomyces sp. strain MPPS2 was characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS) and 16S rDNA sequence analysis. 16S rDNA nucleotide sequence analysis result was deposited in NCBI GenBank® under accession number MT825616.
AtıfScopus28WoS22OpenAlex27İncele - MakaleYalnız künye2017Scopus SJRQ2The surface morphology research of the BGaN thin films deposited by thermionic vacuum arc
Özen, Soner; Pat, Suat; Şenay, Volkan; Korkmaz, Şadan
In this paper, BGaN thin films with two different thicknesses were deposited on two different substrates and their surface morphologies were investigated. The amorphous glass and semi-crystalline polyethylene terephthalate substrates were selected. At the same time, two different deposition angles are selected with a view to the effect of deposition angle on surface morphology. The surface and optical properties were determined by using X-ray diffractometer (XRD), atomic force microscope (AFM), spectroscopic ellipsometry (SE) and optical interferometer. The thicknesses of thin films on substrates are about 30 nm and 40 nm. According to the atomic force microscope images, small-dimensional grains observed on relatively large grains. The roughness values of the thin films on the polyethylene terephthalate substrate are lower than on the glass substrate.
AtıfScopus10WoS9OpenAlex10İncele - MakaleYalnız künye2016Scopus SJRQ1Optical, structural, morphological and compositional characterization of a Co-doped GaAs semiconducting thin film produced by thermionic vacuum arc
Şenay, Volkan; Özen, Soner; Pat, Suat; Korkmaz, Şadan
A 80 nm 2 at% Co-doped GaAs thin film was deposited on a glass substrate under a high vacuum condition by means of the thermionic vacuum arc technique using GaAs and Co pellets as source materials. Tools and techniques such as an optical reflectometer, XRD, UV-VIS-NIR spectrophotometer, FESEM, EDX, and AFM were employed to investigate some of the physical properties of the produced film. From the optical investigations, the refractive index at 632.8 nm and optical band gap of the film were determined to be 3.60 and 1.42 eV respectively. XRD characterization indicated that the film contained GaAs and Co phases. A uniform surface morphology with fine grain covering the entire surface was observed through the FESEM and AFM studies, while 30 nm grain size and 2.72 nm root mean square roughness were obtained. The EDX analysis also confirmed the presence of Ga, As and Co in the film.
AtıfScopus19WoS17OpenAlex18İncele - Derleme MakaleYalnız künye2016Scopus SJRQ4Influence of oxygen partial pressure on the metastable copper oxide thin films
Geçici, Birol; Korkmaz, Šadan; Özen, Soner; Šenay, Volkan; Pat, Suat
Paramelaconite (Cu4O3) is a metastable copper oxide. Metastable copper oxide thin films were deposited on glass substrates by reactive RF magnetron sputtering in argon (Ar) and oxygen (O2) gas mixture atmospheres. Ar/O2 gas ratios in the sputtering ambient were chosen as 1/1 and 1/9. The surface and optical properties were determined by X-ray diffractometer (XRD), atomic force microscope (AFM) and UV-Vis spectrophotometer. The XRD patterns of the samples exhibited single strong diffraction peaks at 35.39° and 35.49° , corresponding to the (202) peak of Cu4O3. The mean thickness values were measured as 100 nm and 80 nm for the films deposited at 1/1 and 1/9 Ar/O2 gas ratios, respectively. The samples showed low transmittance and high absorbance in the high frequency region.
AtıfScopus1WoS1OpenAlex1İncele - MakaleAçık Erişim2016Scopus SJRQ2Optical, morphological and mechanical properties of an Al-Al2O3 nanocomposite thin film grown by thermionic vacuum arc
Şenay, Volkan; Özen, Soner; Pat, Suat; Korkmaz, Şadan
An Al-Al2O3 nanocomposite thin film was deposited onto a glass substrate in high vacuum condition using Al2O3 pellets as source material by means of the thermionic vacuum arc technique in just 50 s. UV-visible spectrophotometer, optical reflectometer, spectroscopic ellipsometer, XRD, FESEM and AFM were employed to investigate the optical, structural morphological and mechanical properties of the produced film. The film exhibited a high transmittance (above 80%) in the 400-1000 nm region. The dispersion of the refractive index was discussed in terms of the single oscillator model. The optical band gap value derived from the Wemple-DiDomenico dispersion relationship was 5.7 eV. It was observed that the results of the optical investigations agreed well with Al2O3 thin films. XRD characterization showed that the film contained Al and Al2O3 phases. The FESEM analysis revealed that the film morphology had a dense characteristic. 2D and 3D AFM micrographs indicated a smooth surface with a low value of average roughness. When compared to the mechanical properties of Al2O3 thin films, it was observed that the hardness and Young's modulus reduced due to presence of ductile Al particles.
AtıfScopus9WoS8OpenAlex11İncele - MakaleAçık Erişim2015Scopus SJRQ1Investigation on the morphology and surface free energy of the AlGaN thin film
Özen, Soner; Şenay, Volkan; Pat, Suat; Korkmaz, Şadan
The purpose of this paper is to analyze surface properties of AlGaN thin film produced using thermionic vacuum arc technique. Thermionic vacuum arc is an alternative deposition technique for GaN thin films that produces in a very short production time for GaN-based solid-state applications. XRD results showed that AlGaN thin film with cubic crystal structure on a amorphous glass was grown. Conductivity type of AlGaN thin film is determined as p-type by hot-probe method which is a very simple method. The surface morphology was analyzed and discussed using field emission scanning electron microscopy (FESEM) and atomic force microscopy. The contact angles in four different testing liquid and surface free energy of the AlGaN thin film were investigated by optical tensiometer.
AtıfScopus27WoS27OpenAlex28İncele - MakaleYalnız künye2015Scopus SJRQ3Some physical properties of the SiGe thin film coatings by thermionic vacuum arc (TVA)
Özen, Soner; Pat, Suat; Şenay, Volkan; Korkmaz, Şadan; Geçici, Birol
SiGe thin films were deposited on glass and PET substrate by the thermionic vacuum arc (TVA) method for the first time. TVA is an anodic plasma generator which works in high vacuum conditions. Highly pure and quality films can be deposited on different substrates by means of this method. In order to characterize the produced films, X-ray diffraction, field emission scanning electron microscope (FESEM), atomic force microscope (AFM), energy dispersive X-ray spectrometer (EDX), optical tensiometer, UV-Vis spectrophotometer and spectroscopic ellipsometer (SE) devices were used. The obtained XRD peaks at 47° and 75° are described to the reflections of (220) and (331) planes of Ge or Si. According to the measurement results, substrates materials are affect the surface and optical properties of the deposited SiGe layers. SiGe coated samples with low optical band gaps exhibit low transparency and high absorption. The structures are homogenous and less rough.
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