Yayınlar
Koleksiyondaki öğeler
- BildiriAçık Erişim2026Scopus SJRQ4Investigation of Surface Leakage Currents of High Voltage Insulators Under Different Pollution Conditions at Power Frequency AC Voltage
Külekçioğlu, Abdülcelil; Çetin, Muhammed Sefa; Gülan, Harun; Özdemir, Mahmut Temel; Gençoğlu, Muhsin Tunay; Cebeci, Mehmet
In this paper, the electrical behavior of high voltage insulators under different pollution conditions has been investigated experimentally at power frequency (50 Hz) alternating voltage. The main objective of the study is to reveal the effect of pollution layers on the surface leakage currents and flashover voltages of insulators. For this purpose, a climatic chamber with controllable temperature and humidity conditions, together with a 200 kV high voltage test system, was employed. Three types of insulators (standard porcelain, fog-type porcelain, and silicone composite) were tested, and artificial pollution layers of varying densities were applied to their surfaces in accordance with standard procedures. During the experiments, the surface leakage currents were recorded, and flashover voltages were determined by gradually increasing the applied voltage. The obtained data enable comparative analyses for different pollution levels and insulator types. The originality of this study lies in providing a comprehensive dataset through numerous experiments under controlled laboratory conditions, thereby addressing gaps in the existing literature. This dataset establishes a solid foundation for the modeling of insulators electrical behavior and for the development of new approaches in future research.
- MakaleAçık Erişim2025Scopus SJRQ1Self-Compassion Around the World: Measurement Invariance of the Short Form of the Self-Compassion Scale (SCS-SF) Across 65 Nations, 40 Languages, Gender Identities, and Age Groups
Swami, Viren; Tran, Ulrich S.; Voracek, Martin; Aavik, Toivo; Ranjbar, Hamed Abdollahpour; Adebayo, Sulaiman Olanrewaju; Afhami, Reza; Ahmed, Oli; Aimé, Annie; Akel, Marwan
Objectives: The 12-item Self-Compassion Scale–Short Form (SCS–SF) is a widely used instrument for the assessment of self-compassion. To date, there have been few examinations of this instrument’s psychometric properties, particularly across nations and languages. Therefore, we used data from the Body Image in Nature Survey (BINS) to assess measurement invariance of the SCS–SF across nations, languages, gender identities, and age groups. Methods: Participants (N = 56,968) from 65 nations completed the SCS–SF in 40 languages. Using these data, we tested various hypothesised models of the SCS–SF in the total sample and, using multi-group confirmatory factor analysis, tested for invariance of the optimal model across national groups, languages, gender identities, and age groups. Results: In the total dataset, we found that an 11-item, 2-factor model (i.e., SCS-11) provided best fit to the data, with the two factors tapping distinct constructs of compassionate and uncompassionate self-responding. The SCS-11 was found to be partially scalar invariant across national groups and languages, and fully scalar invariant across gender identities and age groups. There was wide variation in latent means for the two factors, particularly across national groups and languages. Further analyses showed negligible associations between the two factors and sociodemographic variables, including marital status, financial security, and urbanicity. Conclusions: Our results suggest that it may be possible to derive a stable 2-factor model of the SCS–SF for use in cross-cultural research, but also highlight the likelihood of cross-national and cross-linguistic variations in the way that self-compassion is understood.
AtıfScopus21OpenAlex23
İncele - MakaleAçık Erişim2026Scopus SJRQ3An Artificial Neural Network Modeling of Solar Drying of Mint: Energy, Exergy, and Drying Kinetics
Gülçimen, Fevzi; Karakaya, Hakan; Durmuş, Aydın
Abstract: Solar drying is an environmentally friendly method for preserving agricultural products; however, limited studies have jointly examined energy–exergy performance and data-driven prediction methods under varying airflow conditions, which restricts performance optimization. This study aims to investigate the effects of inlet airflow rate on energy utilization ratio, energy generation, exergy loss, exergy efficiency, and drying kinetics of mint leaves, and to evaluate the predictive capability of artificial neural network modeling. Thin-layer drying experiments were conducted in a forced convective solar dryer equipped with a newly designed solar air collector at different air mass flow rates. Energy and exergy analyses were conducted using experimental thermodynamic data, and energy utilization and exergy loss were modeled with a feed-forward back-propagation artificial neural network. The energy utilization ratio ranged from 7.45 to 87.1% and increased with decreasing airflow rate. The average exergy losses for air mass flow rates of 0.012, 0.026, and 0.033 kg s–1 were 16.2, 8.2, and 6.88 W, respectively. Both experimental and artificial neural network results showed that increasing airflow rate reduced energy utilization ratio and exergy loss. The artificial neural network predictions exhibited very close agreement with experimental data. The results show that artificial neural networks can accurately predict energy utilization ratio and exergy loss in a forced convective solar dryer. Airflow rate is a key parameter for thermodynamic performance, and the integrated experimental–ANN approach offers a robust tool for optimizing and designing solar drying systems.
AtıfOpenAlex1İncele - MakaleAçık Erişim2025Scopus SJRQ1New comparative approach to multi-level thresholding: chaotically initialized adaptive meta-heuristic optimization methods
Serbet, Fatmanur; Kaya, Turgay
One method aimed at enhancing the performance of meta-heuristic optimization techniques is the incorporation of chaotic systems. Instead of irregular distributions in the search space, chaotic distributions are employed in the initial population of optimization algorithms to improve the efficiency of the search process. This approach enables search agents distributed in a chaotic manner to effectively explore the search space. The initial populations of both the well-established PSO algorithm and the enhanced WSO algorithm, which incorporates advanced search techniques, are distributed in the search space according to the characteristics of Logistic, Chebyshev, Circle, Sine, and Piecewise chaotic maps in this study. The original PSO and WSO algorithms, as well as the resulting chaotically initialized PSO and chaotically initialized WSO algorithms, were tested using 23 benchmark functions. Subsequently, the Otsu method was integrated into the tested optimization algorithms to obtain multi-level thresholding values. These algorithms were applied to five different test images with a manually determined number of thresholds. The results obtained were presented in the study and evaluated using statistical tests.
AtıfScopus13OpenAlex12İncele - MakaleYalnız künye2025Scopus SJRQ2Influence of putrescine treatment on quality and biochemical characteristics of hawthorn fruit during cold storage
Kucuker, Emine; Aglar, Erdal; Ogurlu, Ferhat; Ozcengiz, Ceyda Kizgin; Sumbul, Ahmet
Post-harvest quality and product losses are significant for hawthorn fruits, which have a short shelf life and limited marketing period. This study examined the effects of putrescine applications to maintain the physical quality and biochemical contents of hawthorn fruits and extend their shelf life during cold storage. Hawthorn fruits were treated with different doses of putrescine (0.5 mM, 1 mM, and 2 mM) and stored for 30 days. The effects of putrescine applications on weight loss, decay rate, fruit firmness, soluble solids content (SSC), titratable acidity (TA), total phenolic content, total antioxidant content, individual phenolic compounds, and organic acid properties were evaluated on the 10th, 20th, and 30th days of storage. At the end of the cold storage, the lowest weight loss and decay rate and the highest fruit firmness were observed in the 1 mM putrescine application. In general, putrescine applications maintained total phenolic content, with the increase in total antioxidant content continuing until the 20th day. The highest increase in total phenolic and total antioxidant content was observed with the 1 mM putrescine application. Succinic acid, a decreasing phenolic compound, was identified as the primary acid in hawthorn fruits throughout storage. The storage period and putrescine application dose caused increases and decreases in phenolic compounds. Gallic acid was determined as the highest phenolic compound in hawthorn fruit. The 1 mM putrescine application was found to be the most effective application for organic acids and phenolic compounds. Putrescine, one of the main polyamines, was shown to be an effective method for maintaining the quality and shelf life of hawthorn fruit. Additionally, this study is expected to serve as a foundation for future similar studies.
AtıfScopus4WoS4OpenAlex3İncele - MakaleYalnız künye2026Scopus SJRQ2Lithium Recovery from Boron Processing Wastes via Mechanical Activation-Assisted Water Leaching: Application of Planetary Milling
Boylu, F.; Obuz Teker, Gülsen; Ersever Angur, Gafure; Ozdemir, O.; Çelik, M.S.
In this study, a more sustainable, cost-effective, and environmentally friendly approach for selective lithium extraction via water leach assisted by planetary mill mechanical activation was applied on clayey wastes of the Kırka Boron Plant. A detailed systematic study on wastes was performed to optimize both mechanical activation and leaching conditions and to characterize the active powders by XRD, FTIR and EDS/EDX. The results show that lithium can be recovered at relatively low leach temperatures of 50–60°C and short leach times of 3–5 min, achieving leach recoveries of 44.71 (without salt addition) and 57.71% (with 20% salt addition, w/w) without the need for pre-concentration of the waste. Despite relatively low lithium recoveries, water leaching of activated powder produced remarkably low concentrations of co-leached ionic impurities less than 10 ppm Mg, 20 ppm Ca, and 250 ppm K, compared to significantly higher concentrations observed during 1 M acid leaching (9422 ppm Mg, 564.5 Ca, and 72.5 ppm K, upon 1 M acid leaching, respectively). The presence of Mg ions, in particular, is known to be highly detrimental competing ion in metal recovery processes. Therefore, the proposed method offers both economic and environmental advantages by enabling higher purity lithium recovery under much milder conditions.
AtıfScopus1OpenAlex1İncele - MakaleAçık Erişim2026Scopus SJRQ1Influence of apple pomace and asparaginase on acrylamide levels in cookies and behavior during simulated gastric digestion: risk assessment perspectives
Sevim, Sumeyra; Macit, Arife; Farıa, Miguel A.; Viegas, Olga; Cunha, Sara C.; Kizil, Mevlude; Ferreira, Isabel M.P.L.V.O.
Cookies are widely consumed baked products; however, their contribution to dietary acrylamide (ACR) intake raises increasing health concerns. This study investigated the effects of apple pomace addition and asparaginase treatment on ACR levels in cookies, the fate of ACR during simulated gastric digestion using the INFOGEST semi-dynamic model, and the associated health risks of ACR exposure from cookie consumption. Risk assessment was conducted for adults (18–65 years) and children (3–10 years) using Monte Carlo simulation. Three formulations were evaluated: a control cookie, a cookie in which wheat flour was partially replaced with apple pomace, and a cookie containing asparaginase. Cookies formulated with apple pomace contained significantly lower ACR levels than the control (132 ± 8 μg/kg vs. 215 ± 11 μg/kg; p < 0.05), although the reduction was less pronounced than in cookies containing asparaginase (65 ± 14 μg/kg). During gastric digestion, ACR exhibited formulation-dependent release kinetics. Nevertheless, the total ACR released at the end of digestion was similar for control and pomace cookies, likely due to additional ACR formation in the stomach, despite differences in release patterns throughout digestion. Margin of Exposure (MOE) values for children remained well below 10,000, indicating a potential carcinogenic risk, although reductions of up to 59% were observed for control and pomace cookies after digestion. Target Hazard Quotient (THQ) values showed a slight increase after digestion in both age groups but remained below 1, suggesting no concern for chronic toxicity. Control cookies indicated a potential carcinogenic risk for children (ILCR = 1.56 × 10−4), whereas pomace and asparaginase formulations reduced this risk (ILCR = 9.59 × 10−5 and 4.72 × 10−5, respectively). However, simulated gastric digestion increased ILCR values for both control and pomace cookies (2.24 × 10−4 and 2.33 × 10−4, respectively). These findings indicate that dietary exposure to ACR cannot be assessed solely based on its concentration in food, and that digestive kinetics should be incorporated into health risk assessment.
- MakaleYalnız künye2026Scopus SJRQ1Computational fluid dynamics analysis of battery pack with cooling channel integrated with innovative thermoelectric cooling stations
Yardımcı, Uğurcan; Tuğan, Volkan
In this study, a novel liquid cooled battery thermal management system integrated with a thermoelectric assisted cooling channel has been designed. To prevent battery cells from operating at high temperatures and to ensure a uniform temperature distribution among the cells, multiple thermoelectric stations were placed at various positions along the cooling channel. The performance of four different models created with various temperature combinations, as well as a conventional model without thermoelectrics, was investigated through Computational Fluid Dynamics simulations. In the analyses, five different thermoelectric temperatures (293.15–298.15 K), two different mass flow rates (0.0013 and 0.0018 kg/s), and two different initial temperatures (298.15 and 303.15 K) were examined. The results demonstrated a significant improvement in the performance of the battery thermal management system with the use of the thermoelectric assisted cooling channel. It was determined that lowering the initial temperature from 303.15 K to 298.15 K and increasing the mass flow rate from 0.0013 kg/s to 0.0018 kg/s resulted in better cooling performance and more uniform distribution for the thermoelectric assisted system. Under the conditions of a 0.0013 kg/s mass flow rate and an initial temperature of 303.15 K, the highest reduction in maximum battery temperature, compared to the non-thermoelectric design, was achieved in Model B with 9.207 K. Under the same conditions, the most significant reduction in maximum temperature difference was observed in Model D with 4.758 K. Furthermore, the Root Mean Square Spread analysis results revealed that Model B provided the best performance in terms of temperature distribution.
AtıfScopus7WoS7OpenAlex10İncele - MakaleAçık Erişim2026Scopus SJRQ1Structural and radiation shielding properties of high-entropy rare-earth oxide-doped borosilicate glass
Güler, Ömer; Yılmaz, Demet; Kanca, Muhammed Sait; Kök, Mediha; Taşgın, Yahya
In this study, the incorporation of a high-entropy rare-earth oxide, (GdLaEuPrDyY)2O3 (RE-HEO), into a borosilicate glass matrix was investigated with the aim of improving radiation shielding performance while preserving the structural integrity of the glass. The RE-HEO was first synthesized by high-energy mechanical alloying and then introduced into the glass system at concentrations ranging from 0 to 8 wt% using a conventional melt-quenching process. The structural and microstructural properties of the prepared samples were examined using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy combined with energy-dispersive spectroscopy (SEM–EDS). The analyses confirmed that the amorphous nature of the borosilicate glass was maintained and that the rare-earth elements were homogeneously distributed within the matrix. The radiation shielding performance was evaluated experimentally using Am-241, Ba-133, and Ra-226 gamma sources, and supported by theoretical calculations of key parameters including mass attenuation coefficient (MAC), half-value layer (HVL), mean free path (MFP), effective atomic number (Zeff), exposure buildup factor (EBF), and fast neutron removal cross-section (ΣR). The results showed that increasing RE-HEO content leads to a noticeable improvement in gamma-ray attenuation. In particular, the sample containing 8 wt% RE-HEO exhibited a MAC value of 0.131 cm2/g and an HVL of 2.03 cm at 356 keV, indicating shielding performance comparable to that of conventional lead-containing glasses. In addition, irradiation tests performed using a Co-60 gamma source revealed that the amorphous structure remains stable after exposure. Overall, the findings suggest that RE-HEO-doped borosilicate glass can be considered a promising lead-free alternative for radiation shielding applications.
AtıfScopus1WoS1OpenAlex1İncele - MakaleAçık Erişim2026Scopus SJRQ2Radiation shielding performance of CeO2-reinforced ternary nanocomposites based on biodegradable polymers and waste-derived polystyrene
Pekdemir, Mustafa Ersin; Yilmaz, Demet; Selçuk Pekdemir, Sibel; Gülhan, Aleyna; Yalçin Kuzu, Serpil; Altun, Sedanur; Taşgin, Yahya
The development of sustainable polymer-based materials for radiation shielding has attracted increasing interest, particularly for lightweight and flexible applications. In this study, ternary nanocomposites based on poly (hydroxyalkanoate) (PHA), poly (ε-caprolactone) (PCL), and polystyrene (PS) were prepared and reinforced with cerium oxide (CeO2) nanoparticles (5–15 wt%) to enhance radiation shielding performance. Structural characterization confirmed the preservation of polymer chemical structures and the successful incorporation of crystalline CeO2, while SEM observations revealed a relatively homogeneous nanoparticle dispersion within the ternary matrix, particularly at intermediate filler loadings. Thermal analysis demonstrated enhanced thermal stability with increasing CeO2 content, as evidenced by an increase in residual mass from 0.42% for the neat blend to 11.21% for the nanocomposite containing 15 wt% CeO2, along with a shift of degradation onset temperatures toward higher values. Photon shielding performance was experimentally evaluated in the energy range of 13.37–59.54 keV. The incorporation of 15 wt% CeO2 increased the mass attenuation coefficient (MAC) from 1.277 to 12.366 cm2 g−1 at 13.37 keV, corresponding to an approximately ninefold enhancement, while significantly reducing the half-value layer (HVL) and mean free path (MFP). Neutron shielding analysis showed a slight decrease in thermal neutron attenuation due to hydrogen dilution within the polymer matrix, whereas fast neutron attenuation and neutron removal cross sections exhibited only minor variations; the fast neutron removal cross section increased modestly from 0.1014 to 0.1047 cm−1 with 15 wt% CeO2 addition. Overall, the results highlight clear structure–property–performance relationships in CeO2-reinforced PHA/PCL/PS nanocomposites, demonstrating their potential as lightweight radiation shielding materials for low energy protection with improved thermal stability and shielding efficiency.
AtıfScopus2OpenAlex1
İncele - MakaleYalnız künye2026Scopus SJRQ2Comprehensive Characterization of Nano-Eu2O3 Reinforced Borotellurite Glasses: Synthesis, Physical, Structural, and Gamma and Neutron Attenuation Properties
Durmus, Hasan; Kilic, Gökhan; Ilik, E.; Kavaz, Erkan; Güler, Ömer; Birdoğan, Selcuk; Almisned, Ghada; Tekin, Hüseyin Ozan
This study presents a systematic investigation of lithium borotellurite glasses reinforced with nano-Eu2O3, with the aim to enhance the structural stability and radiation shielding performance. Glasses were synthesized with Eu2O3 concentrations from 0 to 10 mol % and characterized through density, X-ray diffraction, and transmission electron microscopy. The results showed that the density increased steadily from 4.030 to 4.734 g/cm3 with the Eu addition, while the molar volume also expanded, indicating that the incorporation of larger Eu3+ ions induced network expansion alongside densification. The X-ray diffraction patterns showed amorphous structures for all the compositions except Eu(n)2, which exhibited local crystallinity, later suppressed at higher Eu levels. The transmission electron microscopy pictures and energy dispersive spectroscopy mapping showed homogeneous nanoparticle distribution without clustering. Gamma-ray attenuation studies demonstrated clear improvements with Eu doping: the linear attenuation coefficient increased from 8.33 cm−1 (Eu(n)0) to 12.42 cm−1 (Eu(n)10) at 81 keV, while the half-value layer values decreased, confirming superior low-energy absorption. Experimental neutron studies revealed ΣR values comparable to standard neutron moderators, with Eu(n)10 showing a favorable balance of gamma and neutron shielding. Limitations include the restricted photon energy window and single neutron source. Future work should extend testing to higher energies, thermal/epithermal neutron ranges, and mechanical and durability assessments. Overall, nano-Eu2O3 reinforcement provides a promising pathway toward multifunctional transparent shielding glasses.
- MakaleAçık Erişim2026Scopus SJRQ1Investigation of the structural, thermal and radiation shielding properties of (Er0.2Yb0.2Sm0.2La0.2Eu0.2)2Zr2O7 high entropy oxide reinforced tin matrix composite
Güler, Ömer; Yılmaz, Demet; Kanca, M. Sait; Kök, Mediha; Güler, Seval Hale; Taşgın, Yahya
This study investigates the structural, thermal, and radiation shielding properties of (Er0.2Yb0.2Sm0.2La0.2Eu0.2)2Zr2O7 high entropy oxide (HEO) reinforced tin (Sn) matrix composites. In the first stage of the study, HEO powders were synthesized by grinding at 350 rpm for 30 h using a solid-state method with mechanical alloying assistance, and then calcining at 1100 °C for 8 h. In the second stage, composites were produced by mixing HEO-reinforced Sn matrix materials containing 1%, 5%, and 10% reinforcement, pelleting them under 200 MPa pressure, and then sintering them at 300 °C for 3 h. In the first stage of the study, (Er0.2Yb0.2Sm0.2La0.2Eu0.2)2Zr2O7 HEO powders were synthesized using a mechanical alloying-assisted solid-state route. In the second stage, HEO-reinforced Sn matrix composites containing 1 wt%, 5 wt%, and 10 wt% reinforcement were produced. The phase formation and crystallographic structure of the synthesized powders and composites were characterized using X-ray diffraction. Thermal behavior and phase stability were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The thermal analysis results revealed dehydration and structural stabilization processes at intermediate temperatures, while crystallization of the HEO phase was observed at elevated temperatures. In addition, oxidation behavior of the Sn matrix composites was evaluated, showing that the presence of HEO particles significantly suppresses mass gain during high-temperature oxidation, indicating improved thermal stability. Finally, the radiation shielding performance of the samples was experimentally evaluated within the photon energy range of 59.54–609.2 keV using Am-241, Ba-133, and Ra-226 radioactive sources together with a Ultra-Low Energy Germanium (ULEGe) detector. The results demonstrate that the incorporation of HEO particles leads to minor, energy-dependent variations in the radiation attenuation capability of the tin matrix, influenced by the presence of high atomic number rare-earth elements and modified microstructural characteristics. The gamma radiation protection coefficient (RPC) values indicate strong attenuation in the low photon energy region, decreasing to approximately 16–19% at 609.3 keV. Moreover, the measured neutron equivalent dose rates increase from 0.054 µSv/h for pure Sn to 0.285 µSv/h for the Sn–10%HEO composite, indicating that HEO incorporation modifies the neutron interaction behavior of the Sn matrix composites.
- MakaleAçık Erişim2026Scopus SJRQ2Data-Driven Prediction of Climate Variables in Agricultural Cities of India With Hybrid GA-TCN-LSTM Model
Utku, Anil
Accurate prediction of climate variables is important in reducing the effects of natural disasters and taking preventive measures for agriculture and food security, energy sector, public health, and water resources management. For agricultural production, it is essential for producers to determine strategies for their agricultural activities and to increase agricultural productivity. Issues such as determining planting and harvest times, determining pesticides to be used against agricultural pests, selecting products to be planted, irrigation, and sustainable agriculture are directly related to climate variables. In this study, a GA-TCN-LSTM hybrid prediction model was created to determine climate variables such as relative humidity, temperature, wind speed, and dew point in Bhopal, Indore, Kanpur, Ludhiana, and Patna, which are among the prominent cities of India in terms of agricultural production. The hyper-parameters of the developed model using the temporal convolutional networks (TCN) and long short-term memory (LSTM) were optimized with the genetic algorithm (GA), and the GA-TCN-LSTM hybrid model was created. GA-TCN-LSTM was extensively compared with the base TCN-LSTM, convolutional neural network (CNN), LSTM, TCN, and CNN-LSTM. The compared models were tested using approximately 15 years of hourly, up-to-date, and real-time data of the cities. Experiments showed that GA-TCN-LSTM outperformed the compared models and had above 0.9 R-Squared (R2) for the majority of cities and climate variables.
AtıfScopus2WoS1OpenAlex2İncele - MakaleAçık Erişim2026Scopus SJRQ2Production and Thermal–Structural Characterization of Nano-Oxide-Doped Paraffin-Based Phase Change Composite Materials for Thermal Storage Applications
Yücel, Halit Lutfi; Özdemir, Osman; Kahraman, Gökhan
Paraffin-based composite phase change materials (PCMs) have been synthesized for thermal energy storage applications to enhance thermal conductivity and stability while maintaining latent heat storage capacity. In this study, RT42 paraffin was modified with inorganic nano-oxides (Al2O3, CuO, SiO2, and ZnO) in the presence of sodium dodecyl sulfate (SDS) as a surfactant. The incorporation of SDS improved nanoparticle dispersion and reduced agglomeration, resulting in enhanced phase-change behavior and improved structural homogeneity. Differential scanning calorimetry (DSC) analysis revealed slight variations in melting and crystallization temperatures, while the ZnO-doped composite retained up to 92% of the latent heat storage capacity of pure RT42. Among all the investigated composites, the Al2O3-doped sample exhibited the highest thermal conductivity and specific heat capacity. Thermogravimetric analysis (TGA) indicated an increase of approximately 15–20°C in the decomposition temperature, demonstrating enhanced thermal stability. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses confirmed the preservation of the crystalline structure and improved microstructural uniformity. The developed SDS-assisted nano-oxide/RT42 composites exhibit significant potential for passive thermal regulation in renewable energy and building applications.
AtıfScopus1WoS1OpenAlex1İncele - MakaleAçık Erişim2025Scopus SJRQ2In vitro and in silico analyses of cytoprotective, antigenotoxic and antimutagenic potential of Phlomis pungens var. hirta extracts against oxidative damage
Wild Korkmaz, Franziska Johanna; Dogan, Serap; Yilmaz Kardas, Begumhan; Diken, Mehmet Emin; Karasakal, Ömer Faruk; Acar, Mikail
Phlomis pungens var. hirta Velen has been used by local people for food and to treat diseases but there are limited number of investigations in literature about this plant and cyto/genotoxicity analyses have not been done before. Hence, this study aimed to find out cell-protective activity and DNA damage prevention ability of P. pungens var. hirta by MTS, micronucleus, 8-OHdG and somatic mutation recombination tests (SMART). In addition, liquid chromatography, antioxidant/antibacterial activity analyses and in silico biological activity profiling were performed. The healthy lymphocyte cell growth was supported by the plant extracts and none of the extracts was genotoxic. 8-OHdG test showed that methanolic and ethanolic extracts of the plant were able to decrease the oxidative DNA damage. According to the SMART results, extracts could suppress the genotoxic effects of an important environmental pollutant, H2O2. Rutin hydrate and quercetin were found in highest concentrations and the extracts could be characterized as antioxidant/antibacterial. In silico analysis also showed that the major compounds of this plant can be considered as chemoprotective. This is the first study that assessed the cell protective activity and DNA damage prevention capacity of P. pungens var. hirta, which should be regarded as a potential source for nutritional supplements and therapeutic products.
AtıfOpenAlex1İncele - MakaleAçık Erişim2025Scopus SJRQ2Tungsten carbide-based shape memory biopolymer nanocomposites as a promising new gamma radiation shielding material
Pekdemir, Mustafa Ersin; Yılmaz, Demet; Selçuk Pekdemir, Sibel; Taşgın, Yahya; Ekmen, Busenur
In this study, structural, thermal and radiation shielding properties of Polylactic acid (PLA)/polyhydroxyalkanoates (PHAs)/Tungsten Carbide (WC) nanocomposite films were investigated. PHA/PLA/WC composite films were prepared by using different amounts of WC (5%, 10%, 18%, 28%). Characterization of the composite films was carried out by Attenuated Total Reflection Infrared Spectroscopy (ATR-IR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The linear and mass attenuation coefficients (LAC and MAC), mean free path (MFP), Half-Value Layer (HVL), Tenth Value Layer (TVL), effective atomic numbers (Zeff), and effective electron densities (Nel) of the synthesized composite films were experimentally measured from 53.16 to 383.85 keV. Also, the neutron equivalent dose rates for the prepared film samples were determined. Exposure buildup factor (EBF) and fast neutron removal cross section (ΣR) were theoretically calculated. The particle shielding characteristics of the composite films were evaluated. The MFP values at 356.01 keV are 8.211 cm, 7.772 cm, 7.360 cm, 6.710 cm and 5.942 cm for PLA/PHA, PLA/PHA/5%WC, PLA/PHA/10%WC, PLA/PHA/18%WC and PLA/PHA/28%WC, respectively. It was observed that an increase in WC content enhances the gamma shielding abilities in PHA/PLA films. The results revealed that PHA/PLA/WC composite materials can be used as protective coating materials.
AtıfScopus5WoS5OpenAlex6İncele - Kitap BölümüYalnız künye2025Transparency and Reverse Transparency: Understanding Digital Leadership in Light of Agency Theory
Sezgin, Eray Ekin
We live in a digital world where most of our work and life experiences are based on information technologies and the internet. Developments in information technologies affect not only business life but also our social and community lives. Leading in the digital age is much more difficult and complex than leading in a world with no opportunities and no technology. Transparency is critical to digital leadership. The increase in the volume of data with developing technologies leads to increased transparency in organizations and has a significant impact on leadership. However, this also brings challenges. On the one hand, transparency facilitates employee empowerment, but on the other hand, it raises concerns about employee oversight and confidentiality. Moreover, transparency has traditionally been a one-sided construct where control is given to managers, leading to a panoptic scenario. To overcome these concerns and challenges, it is imperative to design new forms of control. In this regard, the contemporary workforce demands reverse transparency in the context of agency theory. Although the concepts of (reverse) transparency, leadership and digitalization are interrelated, there is a research gap on the relationship between the three. By analyzing the theoretical concept through the lens of control and outlining a conceptual implementation process, this study is of an explanatory theoretical nature. The study sheds light on the understanding of the problems related to transparency and reverse transparency in the contemporary workforce and contributes further to the theoretical discourse.
- MakaleYalnız künye2017Scopus SJRQ1Ohmic heating assisted vacuum evaporation of pomegranate juice: Electrical conductivity changes
Icier, Filiz; Yildiz, Hasan; Sabanci, Serdal; Cevik, Mutlu; Cokgezme, Omer Faruk
A novel electrical heating method, named as ohmic heating, was successfully integrated to vacuum evaporation system, and pomegranate juice was concentrated until its total soluble dry matter content reached to 40% by applying three different voltage gradients (7.5, 10, and 12.5 V/cm) at 180 mm Hg absolute pressure in this system. Total evaporation times were determined as 152, 78, and 53 min at the voltage gradients of 7.5, 10, and 12.5 V/cm, respectively. The concentration time of pomegranate juice was shortened about 56% by ohmic heating relative to conventional evaporation. The electrical conductivity values were increased up to reach 25% TSDM for 7.5 V/cm and at 35% TSDM for 10 V/cm, then showed a decreasing pattern. However, it was constant (0.55 ± 0.01 S/m) during evaporation process at 12.5 V/cm. It is recommended that the ohmic heating method could be successfully integrated to vacuum evaporation process to shorten the processing time significantly. Industrial relevance Ohmic heating has been utilized as alternative method for the purpose of heating, pasteurization, cooking etc., and relatively better products can be obtained by ohmic heating. Nowadays, energy efficient systems are needed in concentrated juice production. The integration of ohmic heating to the conventional vacuum systems could serve the production high quality juice concentrates with efficient use of energy. In present study, ohmic heating assisted vacuum evaporation of pomegranate juice was conducted, successfully. This method decreased the total process time for juice concentration, which is critically important for industrial scale productions. This novel method can be implemented to the fruit juice production lines by taking into account of design characteristics of ohmic systems such as electrical conductivity changes depending on both temperature and total soluble solids concentration. The effects of main process parameter, named as voltage gradient, on electrical conductivity changes during electrical heating assisted evaporation process has been also reported in the present study.
AtıfScopus93OpenAlex97İncele - BildiriYalnız künye2017A heuristic algorithm for assembly line balancing with stochastic sequence-dependent setup times
Çil, Zeynel Abidin; Mete, Süleyman; Özceylan, Eren; Diri Kenger, Zülal; Çil, Hande
Having analyzed studies on the assembly line balancing problem considering setup times, a few papers are observed. However, researches show that setup time plays an important role in total production time. Besides, in these studies, the setup times are assumed to be deterministic. Considering setup times to be deterministic decreases proximity of problem to real life application. Because the operation and setup times may vary in real applications due to human factors, machine breakdowns, lack of equipment and environmental factors. Therefore, in this study, assembly line balancing problem is investigated considering the sequence-dependent stochastic setup times. A heuristic approach based on COMSOAL is presented for the problem and it is seen that algorithm is effective for the problem.
AtıfScopus2İncele - MakaleAçık Erişim2017Scopus SJRQ3Fault location determination for transmission lines with different series-compensation levels using transient frequencies
Akmaz, Duzgun; Mamiş, Mehmet Salih; Arkan, Muslum; Tagluk, Mehmet Emin
In this paper, based on the theory of traveling waves, the fault distances on long transmission lines with various series-compensation levels are determined using transient current and voltage frequencies. Transmission lines with series compensation are modeled using Alternative Transients Program software with frequency-dependent effects on the line included in the simulation. The transient current and voltage signals are obtained from the model. A fast Fourier transform is used for frequency-domain conversion and fault location is estimated from the frequencies of fault-generated harmonics in the transient spectrum. The algorithm is implemented in MATLAB. To investigate the effect of compensation on accuracy, the results are obtained for different series-compensation levels. The undesirable source-inductance effect is removed and estimation accuracy is further improved using a waveform-relaxation method. The method is found to be successful in determining fault location on series-compensated transmission lines. The effects of the compensation level, fault resistance, and phase angle are investigated.
AtıfScopus6WoS6OpenAlex7İncele
