Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Dertli, Enes(24)
- Cuce, Erdem(18)
- İspirli, Hümeyra(14)
- Cuce, Pinar Mert(13)
- Alım, Bünyamin(12)
- Mercan, Emin(12)
- Sert, Durmuş(12)
- Şenay, Volkan(12)
- Tozlu, Alperen(11)
- Artar, Musa(10)
- Korkmaz, Şadan(10)
- Pat, Suat(10)
- Yilmaz, Mustafa Tahsin(10)
- Özen, Soner(10)
- Gökçe, H.S.(9)
- Sagdic, Osman(9)
- Şakar, Erdem(9)
- Bayram, Ozkan(8)
- Demirtas, M.(8)
- Purcek, G.(8)
- Ergün, Mustafa(7)
- Yanar, H.(7)
- Demir, Lütfü(6)
- Taylan, Osman(6)
- Abdioglu, M.(5)
- Abdioglu, Murat(5)
- Alim, Bünyamin(5)
- Carbas, Serdar(5)
- Guclu, Tamer(5)
- Gökçe, H. Süleyman(5)
- Sayyed, M.I.(5)
- Han, İbrahim(4)
- Ozturk, K.(4)
- Zhang, Z.F.(4)
- Zhang, Z.J.(4)
- Özahi, Emrah(4)
- Şahin, Engin(4)
- Abusoglu, Aysegul(3)
- Andiç-Çakır, Özge(3)
- Baltakesmez, Ali(3)
Yayınlar
- MakaleYalnız künye2023Scopus SJRQ1Full-scale structural evaluations of İskenderpaşa minaret
Aymelek, Abdullah; Yanik, Yusuf; Demirtaş, Betül; Yildirim, Ömer; Çalik, İsmet; Türker, Temel
Nowadays, innovative methods have been used for observing and structural evaluating of historical structures. In this paper, it is presented the full-scale structural assessments of a minaret after a Finite Element model calibrating according to vibration test results. Also, the structural behaviours under earthquake and wind loads were identified by considering the environmental effects on the selected masonry minaret of İskenderpaşa Mosque. First of all, modal analysis was executed on the three-dimensional Finite Element model created according to field survey in ANSYS Workbench. In-situ vibration tests were implemented at different intervals by using developed vibration measurement system. The experimental modal parameters were attained from collected signals. The experimental results were used as reference values in model calibration of this minaret to reflect the existing structural behaviour. Model calibration process was carried out on the initial model both by changing of material properties of masonry wall and by taking into account the interactions with mosque walls and ground. Full-scale structural evaluation was carried out under earthquake and wind loads on both the initial and the calibrated models in the weak direction of this minaret. The top displacements, drift ratios, principal stress values and their distributions were determined. It was shown that the analyses on the calibrated model produce more realistic structural behaviour.
AtıfScopus21WoS20OpenAlex22
İncele - MakaleYalnız künye2023Scopus SJRQ1Brain MRI high resolution image creation and segmentation with the new GAN method
Altun Güven, Sara; Talu, Muhammed Fatih
Brain magnetic resonance imaging segmentation is a recent and still popular research area. Good and accurate segmentation results play an important role in the diagnosis of cancer or other brain diseases. In this article, a novel Generative Adversarial Network architecture is proposed for brain magnetic resonance imaging segmentation. The proposed method is called SSimDCL (Supervised SimDCL). Four studies were conducted in this article. In the first study, the SSimDCL method on the two-dimensional brain magnetic resonance imaging dataset was compared with the current state-of-art architectures CycleGAN, CUT, FastCUT, DCLGAN, and SimDCL. In the second study, the dataset resolution was improved. In the third study, being measured the efficiency of the newly created dataset. And the SSimDCL is trained for both the dataset with increased resolution and the normal dataset, and the results are obtained. In the fourth study, the results of the SSimDCL and the VolBrain brain magnetic resonance imaging segmentation results, which are widely used today, are included. When VolBrain segmentation and SSimDCL segmentation are compared. The results were compared both visually and metrically. Fréchet Inception Distance (FID), Kernel Inception Distance (KID), Peak Signal to Noise Ratio (PSNR) and Learned Perceptual Image Patch Similarity (LPIPS) were used as measurement metrics. The Jaccard and Dice similarity metrics were also used in the analysis. It was observed that the SSimDCL give satisfactory results in all four studies. This method can be used as an automatic brain MRI image segmentation system.
AtıfScopus42WoS31OpenAlex42İncele - MakaleYayıncıda açık erişim2023Scopus SJRQ1Impact of high-pressure homogenisation of milk on physicochemical, microbiological, and textural characteristics of sheep milk yoghurt
Sert, Durmuş; Mercan, Emin; Tanrıkulu, Mehmet
Yoghurt samples were produced from sheep milk that was high-pressure homogenisation (HPH) treated at 0 (control), 30, 50, 70 and 100 MPa. Depending on the acidification kinetic parameters, HPH treatment increased the acidification rate and shortened the fermentation time. HPH-treated samples had lower pH, increased water holding capacity, decreased syneresis, decreased particle size and higher acetaldehyde content than the control. At 0 and 14 days of storage, the tyrosine value of HPH-treated samples was higher than the control. Although HPH resulted in higher L∗ and a∗ values, it caused lower b∗ values in yoghurt samples. Up to 30 MPa, HPH increased firmness and consistency; however, these were decreased above 50 MPa. During storage, Streptococcus thermophilus and Lactobacillus bulgaricus counts ranged from 6.12 to 8.20 log cfu g−1 and 5.70 to 8.96 log cfu g−1, respectively. Depending on the increasing pressure, HPH caused higher S. thermophilus and L. bulgaricus counts.
AtıfScopus8WoS5OpenAlex10İncele - MakaleYalnız künye2023Scopus SJRQ2Prediction of gamma ray spectrum for 22Na source by feed forward back propagation ANN model
Teke, Cagatay; Akkurt, Iskender; Arslankaya, Seher; Ekmekci, Ismail; Gunoglu, Kadir
The radiation has been used in a variety of different fields since its discovery and thus its measurement becomes vital in these industries. Different type detector may be used to measure gamma rays depends on the purposes of measurements. Gamma ray energy spectrum is an important to determine either elemental analysing of a sample or radiation shielding purposes. On the other hand, Artificial Neural Network (ANN) may be used to predict and analysing of gamma-ray spectrum. In this study, gamma ray spectrum from 22Na source detected in NaI (Tl) detector was estimated by ANN. There have been installed ten different ANN models to find the network structure that produces the best predictive value for the gamma ray spectrum NaI (Tl) Detector. Estimation study has been continued with the ANN model with be possessed of lowest error value. ANN model was created by using energy, distance and gamma-rays energy spectrum (called Io) values. In the ANN model developed using the feed forward back propagation algorithm, were used artificial neurons two in the input layer, ten in the hidden layer and one in the output layer. For the case of present work, the experimental data was used 70% for education, 20% for validation and 10% for testing. The estimated values obtained with the ANN model were compared with the experimental results and a good correlation has been found between them (R2 = 0.99).
AtıfScopus18WoS9OpenAlex27İncele - MakaleYalnız künye2023Scopus SJRQ3Modified distance optimization method for the asymmetric bioreduction conditions of phenyl(thiophen-2-yl)methanone by Weissella paramesenteroides N7
Özdemir, Akın; Şahin, Engin
Chirality plays a significant part in life since it is closely linked to carrying out the many metabolic processes that make up a living being. Chiral secondary alcohols such as diaryl-, aryl heteroaryl-, and diheteroaryl are employed in pharmaceuticals as drug intermediates. Although biocatalytic asymmetric reduction of prochiral ketones containing aromatic and heteroaromatic groups is widely known, biocatalytic reduction of heteroaromatic prochiral ketones containing sulfur heteroatoms is rarely known. Very few studies exist in the literature, including the biocatalytic reduction of phenyl(thiophen-2-yl)methanone (1). Moreover, the biocatalytic reduction of 1 with a mathematical modelling and optimization technique is unknown until now. In this study, Weissella paramesenteroides N7 biocatalyst for the asymmetric bioreduction of 1 using a novel modified distance optimization method. Optimization conditions were found as pH = 6.46, temperature = 26 °C, incubation period = 71 h, agitation speed = 200 rpm by the modified distance optimization method, and it was determined that the conversion and enantiomeric excess (ee) under these conditions could be 98.7% and 98%, respectively. Under these proposed optimization conditions, (S)-phenyl(thiophen-2-yl)methanol ((S)-2) was obtained with >99% ee, >99% conversion, and 97% yield. In addition, 11.29 g of 1 was completely converted into (S)-2 (11.07 g, 97% isolated yield) under optimized conditions. This is the first report about the fabrication of enantiopure (S)-2 in high gram scale using a biocatalyst and a novel modified distance optimization technique. In this study, the successful applicability of the new modified distance optimization method in biocatalytic asymmetric reduction reactions has been successfully demonstrated.
AtıfScopus3WoS3OpenAlex5İncele - MakaleAçık Erişim2023Scopus SJRQ1An extensive survey on radiation protection features of novel hafnium iron-borophosphate glasses: Experimental and theoretical study
Şakar, Erdem; Alım, Bünyamin; Ertap, Hüseyin; Karabulut, Mevlut
This study aimed to determine the radiation (photon and particle) attenuation abilities of Hf added iron-borophosphate glasses considered as a candidate host matrix for Pu containing nuclear waste. Experimental absorption parameters were measured using 133Ba radionuclide for photon radiation, and the same parameters were theoretically calculated using Phy-X/PSD. The obtained data were evaluated comparatively for all glasses depending on the Hf and B contents. It has been determined that all of the glasses examined have photon absorption ability at a level that can be a shielding material for nuclear applications. In addition, the interaction cross-sections with particle radiations were computed using SRIM and ESTAR software. When the data obtained are evaluated thoroughly, it can be said that investigated glasses can be used as shielding in areas that require protection from both photon and particle radiation, in addition to being a candidate material for the vitrification of nuclear wastes containing Pu.
AtıfScopus5WoS6OpenAlex8İncele - MakaleAçık Erişim2023Scopus SJRQ1Optimizing the seismic resilience performance of steel truss bridges by maximum energy dissipation via friction dampers
Artar, Musa; Carbas, Serdar
The primary aim of this study is to propose an innovative design methodology for optimizing the seismic resilience performance of steel truss bridges by dissipating the maximum input seismic energy. Maximum seismic energy dissipation is carried out by means of Pall friction dampers (PFDs), popularly categorized among passive energy-damping devices. PFDs distribute input seismic energy with a slip motion along with friction during an earthquake. For that, it is important to determine the optimal slip load value for the PFDs to start working before the structural elements reach the yield point. To determine the optimal slip load values of the PFDs under earthquake effects, the maximum seismic energy distribution is assured by nature-inspired Squirrel Search (SS) and Water Strider (WS) metaheuristic algorithms for steel truss bridges equipped with PFDs. Finally, steel truss bridges on which PFDs with optimal slip load values have been implemented are optimally designed to achieve the minimal structural weight while satisfying ASD-AISC Code of Practice requirements. In order to demonstrate the validity of the proposed design methodology, two design examples of 113-member and 465-member steel truss bridges steel are presented. The optimal slip loads attained with the SS and WS algorithms by conducting the proposed design methodology are 2.45% and 3.75% of the structural weight for the first design example and 2.64% and 2.63% of the structural weight for the second design example, respectively, which are much lower than those considered in practical applications. Moreover, the numerical results show that by 93.5% and 99.48% maximum distribution rates of input seismic energy are accomplished in the bridges. The results indicate that the proposed design methodology exhibit superior performance in optimizing the seismic resilience performance of steel truss bridges by maximum energy dissipation via friction dampers.
AtıfScopus8WoS4OpenAlex5İncele - MakaleAçık Erişim2023Scopus SJRQ1A novel ignition timing strategy to regulate the energy balance during the warm up phase of an SI engine
Koksal, Hüseyin; Ceviz, Mehmet Akif; Yakut, Kenan; Kaltakkiran, Galip; Özakin, Ahmet Numan
The warm up characteristics of an engine have a significant impact on engine performance and exhaust emissions. In SI engines, the light-off performance of the catalytic converter is also important. One of the methods used to shorten the light off time of the catalytic converter is to retard the ignition time. When the ignition time is retarded, the temperature of the exhaust gases increases. However, in this case, the warm up performance of the engine itself may be adversely affected. In this study, firstly, the effects of ignition timing on the energy balance during the warm up period in an SI test engine were revealed. Then, a novel ignition timing strategy was proposed in order to increase the temperature of the exhaust gases, and not to reduce the engine performance. The novel ignition timing strategy working on the principle of sequentially advanced and retarded ignition at certain intervals during the warm up period provides several advantages. When the novel ignition strategy is applied, the energy loss through the exhaust gas was increased up to 7.2% for several operating conditions, while the reduction in engine performance is eliminated. Moreover, 20% reduction in NO emission has been achieved.
AtıfScopus8WoS8OpenAlex7İncele - MakaleAçık Erişim2023Scopus SJRQ2Determination of the molecular structure and spectroscopic properties of capsaicin
Çınar, Mehmet; Alım, Bünyamin; Alım, Zuhal; Şakar, Erdem
In this study, the ground state molecular structure and spectroscopic features of cis- and trans-forms of capsaicin were investigated using DFT (B3LYP) invoking 6–311++G(d,p) basis set. The optimized geometry of capsaicin was determined for the isolated molecule in a vacuum, and then the vibrational spectra –IR and Raman-were obtained, and the assignments of fundamental vibrational modes were done. By applying the GIAO method, proton and carbon chemical shifts were computed for the gas and solvated phases. Besides using the TD-DFT, the Hirshfeld surface and Molecular Electrostatic Potential surfaces were obtained and evaluated to understand the electronic properties. The Total and partial density of state (TDOS and PDOS) spectra were also examined. All obtained computational results were compared with the previously reported experimental data. A high accuracy was obtained for the ground state geometrical structure, and thus, the vibrational frequencies especially lie on the finger print region are predicted also with a high correlation. Similarly, the optimization of chemical shift values calculated by considering solvent effects with experimental data were found as high R2 values of 0.9953 and 0.9455 for C and H atoms, respectively. This comparison shows that the DFT method precisely predicts capsaicin's molecular and spectroscopic characteristics.
AtıfScopus16WoS16OpenAlex15İncele - MakaleYalnız künye2023Scopus SJRQ1Optimum weight design of steel truss roof systems considering corrosion effect
Yaren Aydoğdu, Afranur; Artar, Musa; Ergün, Mustafa
In this paper, the ideal weight for steel truss roof systems is determined while corrosion is considered. Because one of the most crucial problems that steel truss roof systems may experience during their service life is the effect of corrosion. If a corroded structure is designed without considering this effect during the design phase, significant damages and even collapses may occur before it reaches its service life. For this reason, the aim of this study is to make weight optimizations by considering the corrosion effect of steel truss roof systems. Thus, it has been revealed how corrosion that may develop on the truss members' surfaces affects the structure's overall optimum weight. Swarm intelligence-based algorithm approaches, Ant Colony Optimization (ACO), and Butterfly Optimization Algorithm (BOA) are used for this purpose to determine the optimal weight design of five different steel truss roof systems that were previously researched. The main program, which includes structural analysis (FEA) and optimization algorithms, is coded in the MATLAB programming language. The compression and tension bars selected as the limiting functions of the optimization problems are obtained from the stress, displacement, and slenderness conditions specified in the American Institute of Steel Construction-Allowable Strength Design (AISC-ASD, 1989) standard. It is seen that the optimum weight results obtained from all optimization methods for each structure in the non-corrosive condition are relatively similar. This result proves the correctness of the algorithms proposed in this paper. Then, under the influence of corrosion, the optimal weight designs of the structures are carried out. When the findings for the two cases are examined, it can be seen that the optimum weight values for all structures have slightly increased. This is because larger profiles are required due to overcapacity brought on by section loss. The weight of the structure increases in lockstep with the severity of corrosion. All the results like this are presented in detail with the help of tables and graphs in the relevant sections.
AtıfScopus13WoS11OpenAlex18İncele - MakaleYalnız künye2022Scopus SJRQ1Production and characterisation of goat milk powder made from sonicated whole milk concentrates
Sert, Durmuş; Mercan, Emin
In the present study, goat milk powder (GMP) was produced from sonicated whole milk concentrates for 0–60 min. The physicochemical, functional, and microbiological properties and powder flow behaviours of the GMP samples were determined. Sonication decreased firmness and consistency values of milk concentrate with the increased treatment time. L∗ value of the sonicated GMPs was higher than that of the control. The bulk density of samples was between 0.681 and 0.736 g cm−3, increased by sonication. However, sonication resulted in lower wettability, dispersibility, and foaming capacity. The D [3,2] value of GMPs ranged from 21.9 to 31.1 μm, increased by sonication. Sonication caused reduced cohesion and caking properties of GMPs compared with the control. Also, lower compaction levels at different flow rates were determined in the sonicated samples. In general, powder flow analyses showed that sonication improved GMP flow behaviour. Sonicated samples had reduced microbial load compared with the control.
AtıfScopus12WoS8OpenAlex11İncele - MakaleAçık Erişim2022Scopus SJRQ2Precipitation-hardening stainless steels: Potential use radiation shielding materials
Alım, Bünyamin; Özpolat, Özgür Fırat; Şakar, Erdem; Han, İbrahim; Arslan, İbrahim; Singh, V.P.; Demir, Lütfü
In this study, it was focused on the research of new materials with high attenuation efficiency that can be used as radiation shielding material due to the incapability of conventional materials. In accordance with this purpose, the radiation shielding capabilities of four different precipitation-hardening stainless steels (PH-SSs), which are symbolized 15-5PH, 15-7PH, 17-4PH and 17-7PH, were determined both experimentally and theoretically in a wide range of radiation energy. For experimental measurements, two different detectors (Si(Li) and Na(Tl)) and twenty-three different photon energies (from 22.1 to 1332.5 keV) emitted from seven different radionuclides were used in narrow-beam transmission geometry. Phy-X/PSD software were used for theoretical calculations. The theoretically calculated parameters were determined both in the photon energies emitted by the radionuclides used in the experiment and in the continuous energy range of 0.015–15 MeV. Furthermore, in order to make a remarkable assessment of the integration of PH-SSs to nuclear energy applications, the all results obtained have been compared with the corresponding values of Fe-based steel concretes (steel-scrap (SS) and steel-magnetite (SM)), which are widely used as conventional shield materials in nuclear power plants. Moreover, in order to choose the best material to be used in nuclear applications among the PH-SSs, the results were evaluated comparatively in terms of both the characteristics of the materials and the magnitude of the radiation shielding parameters. Consequently, it was concluded that the material with the best radiation shielding performance among the examined PH-SSs was 15-7PH and the radiation shielding performance ranking was generally in the form of 15-7PH ≥ 15-5PH > 17-4PH > 17-7PH > SM > SS. Due to both high attenuation efficiency and superior properties for radiation shielding, it was determined that the PH-SSs can be used as new shielding materials in nuclear applications.
AtıfScopus25WoS25OpenAlex27İncele - MakaleYalnız künye2022Scopus SJRQ1Seismic behavior assessment of historical Alaeddin Bey Mosque and strengthening suggestions by CFRP fabric and steel plate
Şentürk, İdris; Ergün, Mustafa; Artar, Musa
In this study, the effects of different strengthening methods that can be applied for earthquake-damaged historical masonry structures on structural performance were investigated. For this purpose, the Historical Alaeddin Bey Mosque in the central district of Muş was modeled in three dimensions according to the macromodeling technique using the finite element method in the SAP2000 program. The earthquake performance of the structure was determined by considering the earthquake-acceleration records of Erzincan, Kocaeli, and Van, respectively. The maximum tensile and compressive stresses in all three directions on the structural elements were taken into account as the earthquake behavior parameters of the structure. According to the earthquake analysis made in the time domain, it was determined that the polygonal pulpit of the minaret was at risk of being damaged under the effect of the Erzincan earthquake, and it has been concluded that this region should be strengthened. The damaged area of the minaret was strengthened by the application of CFRP fabric and steel plate materials (together or separately) in five different ways, from inside and outside and at different distance intervals. The conclusions obtained as a result of the earthquake analyses on the reinforced models were examined, and it was explained in detail with the help of tables and graphics that method would be more effective in strengthening such damages.
AtıfScopus40WoS39OpenAlex41İncele - MakaleYalnız künye2022Scopus SJRQ2Evaluation of γ-rays and neutron shielding parameters of high dense bismo-boro-tellurite glasses: Comparative study
Şakar, E.; Özpolat, Ö.F.; Alım, B.; Alsaif, Norah A.M.; Rammah, Y.S.
The main high energy radiation-matter interaction parameters of the 30B2O3-(70-x)TeO2-xBi2O3, where x = 40, 50, 60 and 70 mol% (BTB) glasses have been studied in the wide energy range. The theoretical calculations were made for some special X and γ-ray energies emitted from Fe (55), Am (241), Cs (137) and Co (60) radioactive sources for photon energies in the range of 15 keV - 15 MeV. All evaluated radiation shielding parameters were compared with some selected concretes (Ordinary concrete (OC), Hematite-Serpenite (HS) and Basalt-Magnetide (BM)), and glasses (Te and Pb based). The BTB- glasses have higher mass attenuation coefficient (MAC) values than other glasses (Te and Pb based) and concretes (OC, HS, and BM). The half value layer (HVL) of the investigated BTB-glasses has the following trend: OC > HS > BM > Te-Glass > Pb-glass > BTB40 > BTB50 > BTB60 > BTB70. In terms of mean free path (MFP), the BTB70 coded glass has the lowest MFP values due to the highest Bi2O3 content. In terms of the Zeff values of BTB coded glasses vary between 70 and 75 at the lowest energy level. The effective atomic number (Zeff) values in this energy region were 48.974 and 63.102 for Te and Pb glasses, respectively, and 13,339, 15.520 and 15.894 for OC, HS and BM concretes. The BTB-coded glasses have lower exposure buildup factor (EBF) than all other glass and concrete up to 3 MeV photon energies. The energy absorption buildup factor (EABF) values range from 1 to 4.2 for all samples at 1 MFP and at 40 MFP values, it reaches 108 for BTB coded glasses and 1010 for Te-based glass. Results confirmed that BTB- glasses, especially BTB70 glass sample can be used in applications requiring radiation safety.
AtıfScopus17WoS16OpenAlex17İncele - MakaleYalnız künye2022Scopus SJRQ1Bioactive and technological properties of an α-D-glucan synthesized by Weissella cibaria PDER21
Yilmaz, Mustafa Tahsin; Ispirli, Humeyra; Taylan, Osman; Alamoudi, Mohammed; Dertli, Enes
A slimy-mucinous-type colony of EPS-producing Weissella cibaria PDER21 was isolated and identified. The monomer composition was glucose, showing that the EPS is a glucan type homopolysaccharide, The core structure of (1 → 6)-linked α-D-glucose units including (1 → 3)-linked α-D-glucose branches at a ratio of 93.4/6.6 was revealed by 1H and 13C NMR spectra and confirmed by FTIR analysis. The glucan showed a superior thermal stability with almost no degradation in structure up to 300 °C. XRD analysis revealed the amorphous structure while SEM analysis confirmed the layer-like morphology. The glucan had an antioxidant activity (89.5%), water-holding capacity (103.7%) and water solubility index (80.7%) values, suggesting that the glucan had a strong level of antioxidant properties; good water binding capacity and excellent solubility. The glucan PDER21 is a polysaccharide possessing a good combination of technical and functional attributes, suggesting a great deal of potential for use in the food industry.
AtıfScopus42WoS41OpenAlex40
İncele - MakaleAçık Erişim2022Scopus SJRQ1Comparison of theoretical frameworks of doctoral theses on the field of instructional technology: The Turkey-US case
Şimşek, Eda Saka; Atila, Gülşah; Aydın, Abdulkerim; Reisoğlu, İlknur; Göktaş, Yüksel
Although there are suggestions for writing the theoretical framework in the literature, studies on how all sections of research should be structured based on the theoretical framework are limited. The current research compared the structuring of doctoral theses' theoretical frameworks in the field of instructional technology produced in Turkey and the US. Two hundred doctoral theses were subjected to content analysis based on the list of criteria developed by the researchers. The data collection tool includes the criteria of formality, language, definition and association, purpose and significance, methodological procedures, and presentation and interpretation of results. Independent factorial ANOVA were used to determine whether country and method affected the data obtained from the analyzed theses. The analysis of the data showed that the US-based theses were structured in accordance with the established criteria in all aspects except for purpose and importance. Method did not affect consistency with the criteria. The results of the study are anticipated to guide graduate students, thesis advisors, and researchers preparing theses and articles.
AtıfScopus3WoS2OpenAlex4İncele - BildiriYalnız künye2022Scopus SJRQ2Ultrasonicate-assisted preparation of eumelanin-loaded nano/microparticles based on polylactide stereocomplex
Putri, Oceu Dwi; Petchsuk, Atitsa; Bayram, Sinan; Opaprakasit, Pakorn
The utilization of ultrasonication in the preparation of polymeric nano/microparticles has attracted vast attention due to its simplicity with low cost and high energy efficiency. The occurrence of acoustic cavitation generated by the ultrasonication process can enhance droplet disintegration, allowing the improved stability of emulsions. In this study, eumelanin-loaded nano/microparticles were prepared by employing polylactide stereocomplex (sc-PLA) formed by blending of poly(D-lactide-caprolactone-D-lactide), P(DLA-b-CL-b-DLA), triblock copolymer with linear poly(L-lactide), PLLA. The particles were prepared through an oil in water emulsion (O/W) technique followed by a solvent evaporation. The effect of ultrasonication on the encapsulation efficiency and physicochemical properties of the nano/microparticles was evaluated. The results showed that ultrasonication treatment could control nano/microparticles' shape, size, and size distribution, which enhanced the particle stability and the entrapment efficiency of eumelanin. Particle size distribution of ultrasound-assisted nano/microparticles was in a range of 0.38–135 μm, while those without ultrasonication had a broader distribution from 0.38–153 μm. Higher zeta potential was also observed in the ultrasound-assisted nano/microparticles, reflecting their higher suspension stability. The ultrasonication treatment led to higher eumelanin encapsulation efficiency (46.6%) with higher thermal stability and crystallinity, promoted by the formation of higher contents of the stereocomplex crystallites. The results confirm that ultrasonicate-assisted emulsification can be effectively used to fabricate the functional eumelanin-loaded nano/microparticles.
AtıfScopus5OpenAlex3İncele - MakaleAçık Erişim2022Scopus SJRQ1Techno-economic assessment of a synthetic fuel production facility by hydrogenation of CO2 captured from biogas
Tozlu, Alperen
In this study, a thermodynamic and economic analysis of a synthetic fuel production facility by utilizing the hydrogenation of CO2 captured from biogas is carried out. It is aimed to produce methanol, a synthetic fuel by hydrogenation of carbon dioxide. A PEM electrolyzer driven by grid-tie solar PV modules is used to supply the hydrogen need of methanol. The CO2 is captured from biogas produced in an actual wastewater treatment plant by a water washing unit which is a method of biogas purification. The required power which is generated by PV panels, in order to produce methanol, is found to be 2923 kW. Herein, the electricity consumption of 2875 kW, which is the main part of the total electricity generation, belongs to the PEM system. As a result of the study, the daily methanol production is found to be as 1674 kg. The electricity, hydrogen and methanol production costs are found to be $ 0.043 kWh−1, $ 3.156 kg−1, and $ 0.693 kg−1, respectively. Solar availability, methanol yield from the reactor, and PEM overpotentials are significant factors effecting the product cost. The results of the study presents feasible methanol production costs with reasonable investment requirements. Moreover, the efficiency of the cogeneration plant could be increased via enriching the biogas while emissions are reduced.
AtıfScopus34WoS32OpenAlex37İncele - MakaleAçık Erişim2022Scopus SJRQ1High optical response NiO, Pd/NiO and Pd/WO3 hydrogen sensors
Çoban, Ömer; Tekmen, Süleyman; Gür, Emre; Tüzemen, Sebahattin
In this study, NiO and WO3 oxide semiconductors were fabricated on glass substrates by RF Magnetron Sputtering technique. Structural and optical characterizations of the semiconductors were performed using XRD, SEM, and optical absorption measurements. NiO and WO3 thin films were occasionally coated with palladium. In order to investigate the optical response of these semiconductors under hydrogen gas exposure, an optical gas sensor test system was installed and programmed. In both of the coated and uncoated cases, optical absorption changes due to hydrogen gas exposure on the surface were investigated. It was observed that these changes occur between 450 and 850 nm wave lengths range. The absorption in the NiO semiconductor was reduced between these wave lengths, while the absorption was increased in the WO3 semiconductor. In the uncoated state, only NiO gave an optical response to hydrogen gas. While the palladium coated NiO (Pd/NiO) sensor had the best response and recovery times of respectively 70 s and 206 s for 2% fraction of H2 gas at 300 °C constant temperature, the Pd/WO3 sensor gave the best response time of 340 s. Palladium coating resulted in approximately 150% increase in the responses of the NiO sensors at higher H2 concentration. The lower limit of H2 sensing of the Pd/NiO sensors at 300 °C was at the H2 fraction of 0.05%, while for Pd/WO3 sensors this value was 0.025%.
AtıfScopus26WoS25OpenAlex26İncele - MakaleYalnız künye2022Scopus SJRQ1Investigation of antibacterial, antifungal, antibiofilm, antioxidant and anticancer properties of methanol extracts of Salvia marashica İlçim, Celep & Doğan and Salvia caespitosa Montbret & Aucher ex Benth plants with medicinal importance
Bostanci, Maside Temiz; Bulbul, Ali Savas; Celik, Ibrahim Seyfettin; Kocabas, Yusuf Ziya; Burhan, Hakan; Bayat, Ramazan; Sen, Fatih; Zakariae, Nilofar; Esmaeili, Roghayeh; Jafari, Hedayat
In this study, Antimicrobial, Antifungal and Antibiofilm activity tests on 16 bacteria and 2 fungi of Salvia marashica İlçim, Celep & Doğan and Salvia caespitosa Montbret & Aucher ex Benth species were performed by Agar Well Diffusion and Microdilution methods. Salvia species showed sensitivity with a zone diameter of 12–16 mm. Concentrations of 0.5 mg/ml to 16 mg/ml by the dilution method were used to determine the Minimum inhibited concentration (MIC) and Minimum bactericidal concentration (MBK). The MIC values of the plants are mostly 0.5 mg/ml - 4 mg/ml and MBC values are between 0.5 mg/ml - 8 mg/ml. Antifungal activity findings are remarkable on the species and it has been observed to have very high effects especially on Candida parapsilosis. When the antioxidant research findings are examined; It was observed that Salvia marashica and Salvia caespitosa plants have approximately 75% antioxidant activity at 1 mg/ml, and findings mostly directly proportional between concentrations and antioxidant activity capacity were recorded. MCF-7 and HUVEC cell lines were used to investigate anticancer activity properties. In line with the findings, while the IC50 value of Salvia marashica on the MCF-7 Cell line was 0.125 mg/ml, it was 1.65 mg/ml in the HUVEC cell line, while the IC50 value of Salvia caespitosa on the MCF-7 Cell line was 0.115 mg/ml in the HUVEC Cell line. It was found to be 9.87 mg/ml. It has been proven that both Salvia species have a cytotoxic effect on the MCF-7 Cell line.
AtıfScopus21WoS16OpenAlex23İncele