Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Gul, Muhammet(85)
- Serdar, Osman(72)
- Güler, Ömer(68)
- Akkurt, Nevzat(61)
- Baskonus, Haci Mehmet(54)
- Alataş, Mevlüt(53)
- Paksoy, Mehmet Yavuz(53)
- Yucesan, Melih(53)
- Bulut, Hasan(51)
- Tekin, H.O.(51)
- ALMisned, Ghada(48)
- Yildirim, Numan(48)
- Benzer, Fulya(47)
- Kocabaş, Mehmet(45)
- Yildirim, Nuran Cikcikoglu(44)
- Kutlu, Banu(41)
- Ince, Muharrem(39)
- Zengin, Gokhan(39)
- Batan, Nevzat(37)
- Utku, Anıl(35)
- Celik, Erkan(33)
- Topal, Murat(32)
- Ezer, Tülay(31)
- Tanyol, Mehtap(31)
- Can, Erkan(30)
- Sulaiman, Tukur Abdulkadir(29)
- Aslan, Naim(28)
- Özkul, İskender(28)
- Aslan, Alper(27)
- Cakilcioglu, Ugur(27)
- Erguven, Gokhan Onder(27)
- Kutluyer, Filiz(27)
- Kök, Mediha(27)
- Ates, Mehmet(26)
- Erten, Fusun(26)
- Kahraman, Gökhan(26)
- Onat, Onur(26)
- Dal, Nursel Alp(25)
- Danabas, Durali(25)
- Say, Yakup(25)
Yayınlar
- MakaleAçık Erişim2024Scopus SJRQ1Application of electrocoagulation process for the disposal of COD, NH3-N and turbidity from the intermediate sanitary landfill leachate
Ogedey, Aysenur; Oguz, Ensar
This study aims to determine the COD, NH3-N and turbidity disposal efficiencies from leachate in the Bingöl landfill and highlight the electrocoagulation (EC) process’s performance in removing these pollutants. After establishing that landfill leachate was intermediate aged, its characteristics were identified using physical, chemical and elemental analyses. Six parallel-connected electrode plates with stainless steel as the cathode and aluminium as the anode were used to construct an electrocoagulation cell. After a 40-min treatment interval, the optimal disposal efficiencies for COD and turbidity from the leachate were determined to be 87% and 62%, respectively, at pH 5. Following a 40-min reaction, BOD5 concentration and BOD5/COD ratio were determined to be 85.75 mg O2/L and 0.64, respectively, at pH 5. At a NaCl concentration of 10 mM, the optimum disposal efficiency for NH3-N was determined to be 33%. The reaction kinetics matched pseudo-first-order (PFO) kinetics due to high correlation coefficients (R2 = 0.93–0.99) in removing COD, NH3-N and turbidity under different experimental conditions. The optimal reaction rate constants were determined as 2.93 × 10−2 min−1, 1.92 × 10−2 min−1 and 7.3 × 10−3 min−1 for the disposal of COD, NH3-N and turbidity, respectively. Energy consumption, unit energy consumption and total consumption cost rose in the EC process when the current density was augmented from 15 to 25 mA/cm2.
AtıfScopus14WoS11OpenAlex12
İncele - MakaleYalnız künye2024Scopus SJRQ1An experimental investigation of the flow control of a circular cylinder in near wake with parallel plates at Re = 7500
Durhasan, Tahir; Ekinci, Fırat; Firat, Erhan; Akilli, Huseyin
The vortex street suppression in the near wake region of the cylinder with parallel plates was investigated using particle image velocimetry (PIV) at Reynolds number of Re = 7500. The rigid plates are designed as flat, parallel with the free-stream direction, and located on both sides of the cylinder. Two different plate lengths (0.5D and 1D based on the cylinder diameter, D) were examined at gap ratios of g/D = 0.1, 0.3, 0.5, 0.7, and 0.9, respectively. Proper Orthogonal Decomposition (POD) analyses were also employed to reveal vortex mechanism in the near wake region. The gap ratio significantly influences the interaction of the vortices. At low gap ratios, the plates directly affect the development of shear layers on both side of the cylinder. The shear layers elongate downstream with a reduction of the vortex shedding frequency. Moreover, Reynolds shear stress, vortex shedding instabilities and vortex street are suppressed in the near wake region with the help of using parallel plates. On the other hand, vortex shedding reinforces instabilities at higher gap ratios. Besides, the most effective gap ratio is different for each the plate lengths to suppress instabilities.
AtıfScopus9WoS8OpenAlex9İncele - MakaleAçık Erişim2024Scopus SJRQ3Evaluation of the Effect of Temperature on the Toxicity of Lambda-Cyhalothrin in Dreissena Polymorpha Using some Biochemical Biomarkers; [Vrednotenje vpliva temperature na toksičnost Lambda-cihalotrina v modelnem organizmu Dreissena Polymorpha z uporabo biokemijskih označevalcev]
Yildirim, Nuran Cikcikoglu; Serdar, Osman; Ketenalp, Zozan
Due to increasing climate change, it has become important to determine whether the dose-response relationship of organisms to some substances is affected by temperature. For this reason, in this study, it was aimed to reveal the effect of the temperature variable on the toxic response using the Dreissena polymorpha model organism and some of its biomarkers. For this purpose, acetylcholinesterase (AChE), catalase (CAT), superoxide dismutase (SOD), glutathione (GSH) and malondialdehyde (MDA) levels in Dreissena polymorpha exposed to subletal concentrations of λ-cyhalothrin at different temperatures were measured using commercial ELISA kits. According to the results obtained, there was a statistically significant increase in MDA levels in the groups exposed to λ-cyhalothrin, while a decrease in GSH levels was found. AChE levels were inhibited especially in the groups exposed high concentrartion of λcyhalothrin. It was also found that the inhibition levels increased depending on the application times. While SOD enzyme activity decreased, CAT enzyme activity increased depending on the exposure concentration. It has been observed that different temperature have different effects on the toxicity of λ-cyhalothrin. It was observed that λ-cyhalothrin caused oxidative stress and neurotoxicity, and the toxicity of λ-cyhalothrin changed depending on the temperature.
- MakaleYalnız künye2024Scopus SJRQ3Functionalized and Ag-Loaded Nano-Delivery System for Doxorubicin: Loading, Controlled Release and Kinetic Studies
Aydogdu, Burcu; Kaplan Ince, Olcay; Ince, Muharrem; Unal, Ilkay
Multi-walled carbon nanotubes (fMWCNTs) that functionalized and loaded Ag nanoparticles (AgNPs) were investigated to adsorp doxorubicin hydrochloride (DXR). DXR release behavior efficiency was determined using kinetic studies. DXR agent was treated into fMWCNTs@AgNPs material with different drug loading rates. The material was successfully established and characterized using transmission electron microscopy, and fourier transform–infrared spectroscopy. Thermogravimetric analysis was performed to elucidate the effect of temperature on mass loss and X-ray diffraction analysis was systematically assessed the crystalline state of DXR. Various kinetic models including Higuchi, Baker Hixson-Crowell, and power-law were applied. It was revealed that DXR has more binding affinity to the fMWCNTs@AgNPs material system surface as a nanocarrier at pH 7.4 and showed more release at pH 5.0. Functionalized material confirmed its efficiency as pH-based drug delivery system. Used material can be utilized as promising nanocarriers, and findings will contribute to the rational design of novel delivery tools for drugs.
- MakaleYalnız künye2024Scopus SJRQ2Uncovering chemical profiles, biological potentials, and protection effect against ECM destruction in H2O2-treated HDF cells of the extracts of Stachys tundjeliensis
Kurt-Celep, Inci; Zheleva-Dimitrova, Dimitrina; Sinan, Kouadio Ibrahime; Uba, Abdullahi Ibrahim; Nilofar; Mahomoodally, Mohamad Fawzi; Aumeeruddy, Muhammad Zakariyyah; Cakilcioglu, Ugur; Dall'Acqua, Stefano; Zengin, Gokhan
The genus Stachys L., one of the largest genera of the Lamiaceae family, is highly represented in Turkey. This study was conducted to determine the bio-pharmaceutical potential and phenolic contents of six different extracts from aerial parts of Stachys tundjeliensis. The obtained results showed that the ethanol extract exhibited the highest antioxidant activity in the antioxidant assays. Meanwhile, the ethanol extract displayed strong inhibitory activity against α-tyrosinase, the dichloromethane extract exhibited potent inhibition against butyrylcholinesterase, and the n-hexane extract against α-amylase. Based on ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry analysis, more than 90 secondary metabolites, including hydroxybenzoic acid, hydroxycinnamic acid, and their glycosides, acylquinic acids, phenylethanoid glycosides, and various flavonoids were identified or tentatively annotated in the studied S. tundjeliensis extracts. It was observed that the application of S. tundjeliensis eliminated H2O2-induced oxidative stress. It was determined that protein levels of phospho-nuclear factor kappa B (NF-κB), receptor for advanced glycation endproducts, and activator protein-1, which are activated in the nucleus, decreased, and the synthesis of matrix metalloproteinase (MMP)-2 and MMP-9 also decreased to basal levels. Overall, these findings suggest that S. tundjeliensis contains diverse bioactive compounds for the development of nutraceuticals or functional foods with potent biological properties.
AtıfScopus12OpenAlex12İncele - MakaleYalnız künye2024Scopus SJRQ1Parental mediation in Turkey: The use of mobile devices in early childhood
Aslan, Alper; Turgut, Yigit Emrah
This study aims to investigate the use of mobile devices including smartphones and tablets in terms of mediation types of parents who have young children. In this case study, which is one of the qualitative research methods, criterion sampling was adopted for the selection of the study group. The fact that parents of 4–7-year-old children who use mobile devices is determined as the principal criterion. Twelve children aged 4–7 and their parents participated in the study. Data were collected through child observations and parent interviews. The results indicated that children with the mediation of parental supervision had fewer problematic behaviors in the use of media and faced fewer online risks. Besides, children whose parents have general restrictive mediation were the most likely to exhibit problematic media use behaviors. Children whose parents have active mediation were also the most likely to face Internet risks. It was observed that children frequently played games and watched videos on mobile devices. Most parents considered their children’s use of mobile devices as risky and harmful, while it was considered as useful only by co-using parents. It was found that children’s use of mobile devices causes physical, psychological, communicational, and cognitive issues while improving their academic abilities, interests, and cognitive structures. Nevertheless, it was discovered that parents used mobile devices to convince their children to go through their daily routines such as eating, bathing, and sleeping or calm them down in the workplace or social environments.
AtıfScopus9WoS8OpenAlex13İncele - MakaleYalnız künye2024Scopus SJRQ1Sharma–Mittal holographic dark energy and scalar field in Bianchi type-I cosmology
Korunur, Sibel
In this work, we studied Sharma–Mittal holographic dark energy model by considering Bianchi type-I cosmology. For this purpose we analyzed equation of state parameter using IR cutoff scale. Also it is reconstructed correspondence between Sharma–Mittal holographic dark energy and tachyon and quintessence scalar fields. Finally, we created plots for the time-evolution of the equation of state, kinetic energy, and scalar potential.
AtıfScopus3WoS4OpenAlex4İncele - MakaleYalnız künye2024Scopus SJRQ2Optimizing the thermoelectric performance of Bi-Sb-Te thin films through compositional engineering
Yüzüak, Gizem Durak; Çetin, Mehmet; Yüzüak, Ercüment
The objective of the present investigation was to systematically investigate the structural and thermoelectric (TE) properties of BixSb2-xTe3 thin films with varying content of Bi. We investigated the impact of different atomic percentages of Bi (4, 6, 8 at. %) on the properties of carrier transport and TE performance. In general, the Seebeck coefficient remained consistent across the thin films. For the 8 at. % Bi thin film, the Seebeck coefficient and electrical conductivity were measured at 230 μV/K and 730 S/cm, respectively, at room temperature. These values were more than 20 times greater than the electrical conductivity observed in the thin films with compositions of 6 and 4 at. % Bi. As a result, the Bi-Sb-Te compound exhibited a TE power factor (PF) of 38x10−4 W/mK2 at 40 °C, surpassing the PFs observed in previous compositions. The analysis of surface microstructure, combined with atomic force microscopy and Kelvin probe microscopy images, revealed that the transport of carriers in films with high Bi content was impeded by the size of particles and scattering sites. On the other hand, an augmentation in Bi content promoted the transfer of charge through crystalline regions, hence improving the mobility of carriers and the total electrical conductivity. The aforementioned results emphasize the significant influence of Bi content on the electrical properties of semiconductors and demonstrate the effectiveness of compositional engineering based on Bi content in the development of TE materials with superior performance. The present study investigates the influence of Bi content on the electrical properties of Bi-Sb-Te thin films, demonstrating that compositional adjustments based on Bi content can impact the performance of TE materials. These findings contribute to the understanding of material optimization in the field of TE.
AtıfScopus4WoS5OpenAlex5İncele - MakaleAçık Erişim2024Scopus SJRQ1Integrating chemical analysis with in vitro, in silico, and network pharmacology to discover potential functional compounds from Marrubium astracanicum subsp. macrodon
Avşar, Ömer Kaan; Kasbolat, Sevgi; Ak, Gunes; Nilofar; Caprioli, Giovanni; Santanatoglia, Agnese; Uysal, Ahmet; Uba, Abdullahi Ibrahim; Ponniya, Sathish Kumar M.; Paksoy, Mehmet Yavuz
The members of the genus Marrubium are of great interest because they contain biologically active compounds. With in this mind, we aimed to examine the chemical profiles and biological activities (antioxidant, enzyme inhibition and antimicrobial effects) of different extracts of Marrubium astracanicum subsp. macrodon. Extractions of the plants were carried out with the solvent n-hexane, acetone, acetone/water (70 %), and water. The antioxidant activity of these extracts was evaluated through six different assays, namely 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), cupric reducing antioxidant capacity (CUPRAC), ferric reducing antioxidant power (FRAP), metal chelating ability (MCA), and phosphomolybdenum (PBD). Additionally, the inhibitory effects of these solvents on five enzymes acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase, amylase, and glucosidase were investigated. The study detected 38 compounds in a plant, with the highest content in acetone and acetone/water extracts. The acetone/water extract demonstrated the highest antioxidant activity aligning with its superior total phenolic (51.9 mg gallic acid equivalent (GAE)/g) and flavonoid (31.0 mg rutin equivalent (RE)/g) content, highlighting a direct correlation between bioactive compound concentration and antioxidant potential across various assays. Regarding the enzyme inhibition activity, the acetone/water extract of this plant exhibited significant AChE inhibition measuring 2.5 mg galantamine equivalent (GALAE)/g and anti-glucosidase activity measuring 1.2 mmol acarbose equivalent (ACAE)/g. In antimicrobial evaluation, the acetone extract exhibited good antimicrobial activity against B. cereus at 0.2 mg/ml dose. In molecular docking analysis, delphinidin 3,5 diglucoside showed a good interaction with the active site of AChE active. Through the application of network pharmacology, an in-depth exploration was conducted to unravel the potential of compounds from M. astracanicum against Alzheimer's disease. The study specifically focused on identifying key targets within the Alzheimer's disease pathway, pinpointing crucial proteins such as Glycogen synthase kinase-3 (GSK3), Prostaglandin-endoperoxide synthase 2 (PTGS2), and Alzheimer's-associated amyloid precursor protein (APP). In summary, the plant can serve as a valuable ingredient in the production of functional products within the pharmaceutical, nutraceutical, and cosmeceutical applications.
AtıfScopus4OpenAlex4İncele - MakaleAçık Erişim2024Scopus SJRQ2Cytotoxic, antioxidant, and enzyme inhibitory activities of Centaurea stapfiana extracts and their HPLC-ESI-QTOF-MS profiles: Insights into an unexplored Centaurea species
Zengin, Gokhan; Fernández-Ochoa, Álvaro; de la Luz Cádiz-Gurrea, María; Jiménez, Francisco-Javier Leyva; Uba, Abdullahi Ibrahim; Ak, Gunes; Soomro, Sanam Iram; Balos, Maruf; Cakilcioglu, Ugur; Rodrigues, Maria João
The members of the genus Centaurea have a great interest in pharmaceutical and nutraceutical fields due to their biological potential. Based on this information, we aimed to evaluate the biological properties (antioxidant, enzyme inhibition and cytotoxicity) and chemical profile of the extract of Centaurea stapfiana, an unstudied species. The highest total phenolic content was found in the ethanol/water extract with 32.17 mg GAE/g. A total of 102 of them were identified by HPLC-ESI-QTOF-MS analysis. These compounds were mainly hydroxybenzoic acid and hydroxycinnamic acid as well as flavonoids. In the antioxidant tests, the ethanol/water extract had the best free radical scavenging and reducing ability. However, in the enzyme inhibition test, the ethanol extract was the most active. The extracts were also tested on two tumour cell lines (RAW 264.7 and HepG2) and one non-tumour cell line (S17). The ethanol extract showed the promising effect on HepG2 (cell viability: 28.6 % at 50 g/ml). Furthermore, we examined the interactions between the compounds and enzymatic and cellular targets. A good interaction was found between quercetin-3-xylosyl-(1- > 6)-glucoside and iNOS. In summary, our results suggest that C. stapfiana can be considered as a versatile raw material for the development of health-promoting applications in the pharmaceutical and cosmeceutical fields.
AtıfScopus13OpenAlex14İncele - MakaleAçık Erişim2024Scopus SJRQ2The Behavior of Ceramic Fiber Geopolymer Concrete under the Effect of High Temperature
Dalğıç, Aras; Yılmazer Polat, Berivan
Geopolymer concrete (GC), also known as green concrete, contains slag, silica fume, and fly ash as binders. The absence of cement in concrete is critical to protect the world from the environmental impacts of cement production. In addition, exposure to high temperatures is a critical parameter that causes loss of strength in concrete. In this study, Geopolymer concrete samples were prepared with 10 different samples containing different proportions of slag, silica fume, and porous ash and subjected to various physical, mechanical, and optical tests. The sample (GS90) with optimum workability and compressive strength, which also showed high performance in water absorption, freeze-thaw, and UPV tests, was used in high-temperature tests. Portland cement concrete (PCC) was used as a control sample. This study investigated the effect of high temperatures on the physical and mechanical properties of fiber-free GCs containing 2%, 5%, and 10% by volume of ceramic fibers. Therefore, fiber-reinforced, fiber-free, and PCC specimens were subjected to high-temperature tests at 100, 300, 600, and 900 °C. As a result of the observation of crack growth, color changes, and compressive strength parameters in the samples subjected to high-temperature tests, the thermal resistance of the 10% ceramic fiber geopolymer concrete sample was 2.5% higher than other samples. There is no study in the literature that examines the behavior of ceramic fiber-reinforced geopolymer concrete at high temperatures. This research revealed an important finding by proving that ceramic fiber reinforcement increases the compressive strength of geopolymer concretes at a remarkable rate after high-temperature impact.
AtıfScopus8WoS10OpenAlex8İncele - MakaleAçık Erişim2024Scopus SJRQ4Erythropoietin and Hypericum perforatum ameliorate Gentamicin–induced nephrotoxicity in rats; [La eritropoyetina y el Hypericum perforatum mejoran la nefrotoxicidad inducida por gentamicina en ratas]
Ak, Tuba Parlak; Sağıroğlu, Meltem; Korkmaz, Gizem Elif; Yaman, Mine
Gentamicin (GM), which causes nephrotoxicity, is an aminoglycoside antibiotic commonly prescribed to treat of gram–negative infections. Erythropoietin (EPO), which has several biological functions including neuroprotection, wound healing and nephroprotection, is a glycoprotein hormone that controls erythropoiesis. Hypericum perforatum (HP) is a medicinal herb with antibacterial and nephroprotective effects. The aim of this study is to demonstrate the efficacy of EPO and HP in GM nephrotoxicity using combined biochemical, histopathological and immunohistochemical evaluations together. A total of 36 male Spraque–Dawley rats were divided into as control, GM (100 mg·kg-1 day), GM+EPO, GM+HP, EPO (1000 IU·kg-1 three consecutive days apart) and HP (200 mg·kg-1 day) groups (n=6) and the experiment lasted for 9 days. GM–induced increased relative kidney weight and increased serum urea nitrogen (BUN), creatinine and urea levels were reduced by EPO and HP. EPO and HP reduced the level of malondialdehyde (MDA), which increased with GM application, and increased the activities of reduced glutathione (GSH), glutathione peroxidase (GSH–Px), and catalase (CAT). GM nephrotoxicity resulted in tubular degeneration, vacuolization and hyaline deposits, glomerular degeneration and interstitial mononuclear cell infiltration. EPO and HP attenuated these histopathological changes. Also, EPO and HP also reduced caspase–3 immunoreactivities, which increased with GM application. It was shown that EPO and HP have attenuating effects on GM–induced kidney injury, and especially the intense antioxidant content of HP has a regulatory effect on the negative consequences of oxidative stress.
- MakaleAçık Erişim2024Scopus SJRQ2Combining chemical profiles and biological abilities of different extracts from Tanacetum nitens (Boiss. & Noë) Grierson using network pharmacology
Dall'Acqua, Stefano; Yagi, Sakina; Sut, Stefania; Uba, Abdullahi Ibrahim; Ponniya, Sathish Kumar M.; Koyuncu, Ismail; Toprak, Kenan; Balos, Mehmet Maruf; Kaplan, Alevcan; Çakılcıoğlu, Uğur
Tanacetum nitens (Boiss. & Noë) Grierson is an aromatic perennial herb used in Turkish traditional medicine to treat headache, fever, and skin diseases. This study aimed to investigate the chemical composition, antioxidant, enzyme inhibition, and cytotoxic properties of T. nitens aerial parts. Organic solvent extracts were prepared by sequential maceration in hexane, dichloromethane, ethyl acetate, and methanol while aqueous extracts were obtained by maceration or infusion. Nuclear magnetic resonance (NMR) and LC-DAD-MS analysis allowed the identification and quantification of different phytoconstituents including parthenolide, tanacetol B, tatridin B, quinic acid derivatives, β-sitosterol, and glycoside derivatives of quercetin and luteolin. The type and amount of these phytochemicals recovered by each solvent were variable and significant enough to impact the biological activities of the plant. Methanolic and aqueous extracts displayed the highest scavenging and ions-reducing properties while the dichloromethane and ethyl acetate extracts exerted the best total antioxidant activity and metal chelating power. Results of enzyme inhibition activity showed that the hexane, ethyl acetate, and dichloromethane extracts had comparable anti-acetylcholinesterase activity and the latter extract revealed the highest anti-butyrylcholinesterase activity. The best α-amylase and α-glucosidase inhibition activities were obtained from the hexane extract. The dichloromethane and ethyl acetate extracts exhibited the highest cytotoxic effect against the prostate carcinoma DU-145 cells. In conclusion, these findings indicated that T. nitens can be a promising source of biomolecules with potential therapeutic applications.
AtıfScopus7OpenAlex7İncele - MakaleAçık Erişim2024Scopus SJRQ1A new chaotic system and its practical applications in substitution box and random number generator
Artuğer, Fırat; Özkaynak, Fatih
One of the successful practical applications of chaos theory and nonlinear dynamics is chaos-based cryptology studies. In this study, a new chaotic system is proposed. The proposed chaotic system generator model has a simple algorithmic structure. In addition to, generated chaotic systems have rich dynamics. It has been examined whether this system has potential advantages, especially for information security applications. As a result of the analysis and experimental studies, it is seen that the study makes many contributions to the literature. The simple mathematical generator structure has the potential to reduce computational complexity, which is an important problem for cryptology applications. One of the most comprehensive studies has been realized for chaos-based substitution box designs. 70,000 different substitution box structures have been generated. It has been known that the highest nonlinearity value that can be achieved for designs that transform chaotic system outputs into substitution box structures is 106.75 today. It has been shown that this value may be higher. The new highest nonlinearity value is calculated as 107. Side channel analysis has been examined for substitution box structures with the highest nonlinearity value among the substitution boxes generated in the study. Analysis results show that the proposed new substitution box structures may have an advantage for application-oriented attacks. Among the generated substitution box structures, 289 substitution box structures with a nonlinearity value of 106 and above are presented as a public dataset for researchers to use. In addition, 3 different random sequences with a length of 1 million-bit were produced with the proposed map, and the NIST SP 800–22 test was applied. Test results for all datasets were successful. In this way, the proposed map can also be used as a random number generator.
AtıfScopus13İncele - MakaleAçık Erişim2024Scopus SJRQ4Comparative And Dynamic Analysis of Türkiye's Competitiveness in Unmanned Aerial Vehicles; [İnsansız Hava Araçlarında Türkiye’nin Rekabet Gücünün Karşılaştırmalı ve Dinamik Analizi]
Aydin, Üzeyir; Ateş, Erdem; Öztürk, Hasan
The study aims to determine the competitiveness of Türkiye’s UAV exports in a dynamic framework. The analysis used data from the first 20 countries with the largest share in the production and trade of products designated as UAVs by the Harmonic System six-digit and by the European Commission for 2012-2021. Within the scope of the study, it is determined that some countries have high competitiveness in 4 product groups examined with five different foreign trade indexes. It is concluded that Türkiye has strategic and dynamic superiority in two of the four product groups.
AtıfOpenAlex2TR Dizin1
İncele - MakaleYalnız künye2024Scopus SJRQ2CeO2/SWCNT nanocomposite coating: A novel approach for corrosion application
Doğan, Fatih
The coatings were prepared by blending different concentrations of SWCNTs and CeO2 particles with an epoxy resin by hydrothermal method, which was then applied to the substrate through the doctor blade technique. The mixtures were transferred into a 1-L capacity autoclave with a teflon-lined flange type and subjected to hydrothermal treatment at 100°C for 3 h. The surface coatings were applied using a doctor blade. Subsequently, the coated materials were placed in an oven and dried for 12 h at 50°C under vacuum conditions. The samples' structural analysis was examined through x-ray diffraction (XRD). XRD analysis verified the CeO2/SWCNT composite coating, and Fourier transform infrared spectroscopy (FTIR) was utilized to assess the presence of functional groups. Thermodynamic properties and thermal stability of composite coatings that were modified with SWCNTs and CeO2 particles were studied by thermogravimetric analysis (TGA). The impact of the CeO2/SWCNT composite on the anticorrosion capabilities of the epoxy coating was examined through electrochemical impedance spectroscopy (EIS), Nyquist curve, and Tafel slope characterization. Corrosion tests were conducted on the CeO2/SWCNT composite coatings in a 3.5 wt% sodium chloride (NaCl) solution at 25°C to improve corrosion resistance. The concentration of 0.4 wt% CeO2 was found to be optimal for achieving effective corrosion resistance. The composite coating CNT0.6-C0.4 exhibited significantly higher Ecorr (−426 V) and lower Icorr (2.96 × 10−6 A cm−2) values compared to samples from the CNT0, CNT0.2, and CNT0.6 groups. The paper presents a viable solution with CeO2/SWCNT composite coating for the engineering application of corrosive-inhibiting coatings.
AtıfScopus1WoS1İncele - MakaleAçık Erişim2024Scopus SJRQ1Spread patterns of COVID-19 in European countries: hybrid deep learning model for prediction and transmission analysis
Utku, Anıl; Akcayol, M. Ali
The COVID-19 pandemic has profoundly impacted healthcare systems and economies worldwide, leading to the implementation of travel restrictions and social measures. Efforts such as vaccination campaigns, testing, and surveillance have played a crucial role in containing the spread of the virus and safeguarding public health. There needs to be more research exploring the transmission dynamics of COVID-19, particularly within European nations. Therefore, the primary objective of this research was to examine the spread patterns of COVID-19 across various European countries. Doing so makes it possible to implement preventive measures, allocate resources, and optimize treatment strategies based on projected case and mortality rates. For this purpose, a hybrid prediction model combining CNN and LSTM models was developed. The performance of this hybrid model was compared against several other models, including CNN, k-NN, LR, LSTM, MLP, RF, SVM, and XGBoost. The empirical findings revealed that the CNN-LSTM hybrid model exhibited superior performance compared to alternative models in effectively predicting the transmission of COVID-19 within European nations. Furthermore, examining the peak of case and death dates provided insights into the dynamics of COVID-19 transmission among European countries. Chord diagrams were drawn to analyze the inter-country transmission patterns of COVID-19 over 5-day and 14-day intervals.
AtıfScopus6WoS3OpenAlex7İncele - MakaleYalnız künye2024Scopus SJRQ3Using the Particle Swarm Optimization (PSO) Algorithm for Baseflow Separation and Determining the Trends for the Yesilirmak River (North Turkey)
Acar, R.; Saplioglu, K.
Estimation of baseflow is a complex hydrographic task. Baseflow techniques and coefficients vary from basin to basin, stream to stream, and year to year. In this study, meta-heuristic optimization is used to automatically identify baseflow. The Particle Swarm Optimization (PSO), a meta-heuristic optimization approach, is chosen. The constraint and cost functions were determined using the PSO algorithm, Lyne and Hollick techniques, and a computer application. Over the period 1980–2015, the data were collected at the Kale station in the Yesilirmak River basin to validate the study model. The results show that the hydrographs and baseflow dividing line were separated effectively. It has also been revealed that the PSO has a high speed as well as a high level of precision. In the research, in addition to the baseflow separation, the hydrograph, baseflow, and ratio of the baseflow to the streamflow at the station No. 1402 were assessed using the Mann–Kendall test and Innovative Trend Test (ITA), and as a result, their trends have been found. By the use of both of these methods, it has been shown that all parameters have an unfavorable trend. In addition, the research came to some other significant conclusions, such as the fact that the baseflow declines in tandem with the flow values and that the baseflow rates are low in years with high peak values of the hydrograph.
AtıfScopus4WoS5OpenAlex6İncele - MakaleYalnız künye2024Scopus SJRQ2Dynamic Analysis and Metallographic Examination of Linings with Different Composite Contents used in the Brakes of a Hydraulic Turbine
Işık, Erdem; Kahraman, Gökhan
The main aim of this study was to find ways to increase the performance and life of generator brake linings, which can lead to cost reduction and adequate downtime periods for hydroelectric power plants. First, the dynamic analysis of the linings used in hydraulic turbines was realized and their reactions were examined under different operating conditions. Second, two types of brake linings with different composite components produced in the market were examined metallographically and tested to determine both the stopping performance and durability time of the turbine-generator unit for a sufficient period of time in the vertical 150-megawatt Francis turbine with approximately 500 tons of rotary weight. As a result of these experiments, the lining with the boron component led to much better results than the other brake linings. It has been determined that the boron-containing lining makes 100 stops more than the other lining and stops 20 s earlier in one stop. Therefore, the use of a composite lining with boron content in the braking systems of hydroelectric power plants significantly reduces maintenance incidents and operation costs as it prolongs brake replacement periods in these plants. Graphical Abstract: (Figure presented.)
AtıfScopus1WoS1OpenAlex1İncele - MakaleYalnız künye2024Scopus SJRQ1An innovative approach in oat milk production: Ohmic heating
Ak, Ferit; Karakavuk, Emrah; Goksu, Ali; Sabancı, Serdal
This study aimed to produce oat-milk by using the ohmic heating (OH) system and to compare some quality properties of this milk with the milk produced by conventional methods. The solution containing oats was heated from 20 °C to 75 °C using 3 different voltage-gradients, and then oat-milk was obtained by applying a series of processes. It has been determined that as the voltage gradient increased during heating in oat milk production, the processing time shortens, and this time was 482 seconds in the conventional heating process. The effective electrical conductivity values increased as the temperature increased in the OH process during the production of oat-milk and these values vary between 0.13 and 0.41 S/m. Also, some quality characteristics of oat milk such as color and total phenolic content were better preserved in milk obtained by the OH process than conventional heating process. In addition, oat milk obtained by OH process had higher apparent viscosity at all temperatures.
AtıfScopus8WoS6OpenAlex8İncele