Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Gul, Muhammet(86)
- Güler, Ömer(69)
- Akkurt, Nevzat(68)
- Baskonus, Haci Mehmet(53)
- Tekin, H.O.(52)
- Bulut, Hasan(50)
- ALMisned, Ghada(49)
- Serdar, Osman(43)
- Yucesan, Melih(43)
- Paksoy, Mehmet Yavuz(42)
- Yildirim, Numan(41)
- Zengin, Gokhan(40)
- Yildirim, Nuran Cikcikoglu(39)
- Ince, Muharrem(37)
- Kocabaş, Mehmet(37)
- Celik, Erkan(35)
- Benzer, Fulya(33)
- Sulaiman, Tukur Abdulkadir(29)
- Aslan, Naim(27)
- Can, Erkan(27)
- Kutlu, Banu(27)
- Kök, Mediha(27)
- Tanyol, Mehtap(27)
- Danabas, Durali(26)
- Kutluyer, Filiz(26)
- Özkul, İskender(26)
- Ates, Mehmet(25)
- Yildirim, Ozal(25)
- Onat, Onur(23)
- Topal, Murat(23)
- Demir, Veysel(22)
- Erten, Fusun(22)
- Guler, Omer(22)
- Say, Yakup(22)
- Yaman, Mehmet(22)
- Alataş, Mevlüt(21)
- Güler, Seval Hale(21)
- Çimen, Okay(21)
- Baykal, Duygu Sen(20)
- Mete, Suleyman(20)
Yayınlar
- MakaleYalnız künye2024Scopus SJRQ2Stress–strength reliability for electricity systems based on the Bernstein copula approximation
Susam, Selim Orhun; Hudaverdi, Burcu
Electricity is a critical resource for modern society, and its availability is essential for various aspects of daily life, from powering homes to supporting industrial processes and infrastructure. Ensuring a reliable supply of electricity is vital for economic stability and the well-being of a population. As the world moves toward more sustainable and renewable energy sources, understanding the reliability of these sources compared to traditional fossil fuels is crucial. In this study, we develop a methodology that enables the measurement of stress–strength reliability when electricity consumption is considered as the strength variable, positioned between electricity generation from renewable energy sources and fossil fuels as stress variables. We achieve this using the copula-based reliability with Bernstein copula approximation. The methodology is applied to the U.S. monthly electricity data. The result shows that the current rates of electricity output from fossil fuels and renewables will not be sufficient to meet the demand for electricity.
AtıfScopus2WoS3OpenAlex3
İncele - MakaleYalnız künye2024Scopus SJRQ2Some nanotoxicity effects of copper (60-80 nm) and copper oxide (40 nm) nanoparticles on Artemia salina
Cimen, Isıl Canan Cicek; Danabas, Durali; Ates, Mehmet
In this study, nanotoxicity tests were made by exposure of Artemia salina to copper (Cu 60-80 nm) and copper oxide (CuO 40 nm) nanoparticles (NPs) at different concentrations (0.2, 1, 5, 10, 25, and 50 mg/L). The LC50 value of Cu (60-80 nm) NPs on the A. salina individuals at the beginning (0), 24th, 48th and 72nd hours and elimination period was 52.37 mg/L while the LC50 value of CuO (40 nm) NPs was 55.39 mg/L. The results of UV-Vis absorbance values showed that all statistical data revealed that maximum effect was observed between 24-30 hours and 25 ppm absorbance concentration was more effective. The multiple R, correlation coefficient (R2) and adjusted R2 values of Cu NP for the suitable Quadratic model were, respectively; 92.96 %, 86.42 % and 76.71 % while they are 98.31 %, 96.64 % and 94.25 % for CuO NP. Also, the data, was indicated effect size significantly changed based on the type and size of NP. Considering the microscope results, it was clearly noticed that A. salina organisms took the NPs in to their body. The accumulation in the gut of A. salina was observed and the images were taken with phase contrast microscope for both of NPs. The highest decrease for survival rates of A. salina individuals exposed to Cu NP was observed in the 10 ppm concentration (43.47 %) and in the 5 ppm concentration (46.20 %) for CuO NP. The results revealed that Cu and CuO NPS showed different toxic effects and that Cu NPs were more toxic than CuO.
AtıfScopus2WoS2İncele - MakaleYalnız künye2024Scopus SJRQ2Production of high entropy (FeNiMnCrV)3O4 oxide by mechanical alloying process and electrochemical performance analysis for Li-ion cells
Dogan, Ebru; Altin, Serdar; Guler, Seval Hale; Guler, Omer; Altin, Emine
In this study, a high entropy oxide material was fabricated from its alloy using mechanical alloying technique in the form of (FeNiMnCrV)3O4 with a symmetry of Fd-3m, and their structural properties were investigated by XRD, SEM-EDS dot mapping, and XPS analyses. The EDS analysis results of oxide and alloy show that Fe, Ni, Mn, Cr, and V have similar ratios for both samples. The elemental ratios were also measured by ICP-MS and the results support the EDS and XPS data. The alloy and oxide powders were used for the production of the anode materials for the half-cell configuration of the battery. The CV analysis of both cells showed that they have similar characteristic redox reactions and the main difference between the two electrodes is the current density values in the peaks. The initial capacity value of the (FeNiMnCrV)3O4 for 10 mA/g was found as 1070 mAh/g for the first cycle which is promising results as an anode material for Li-ion cells.
AtıfScopus3WoS3OpenAlex3İncele - MakaleYayıncıda açık erişim2024Scopus SJRQ2Mechanical and electrical faults detection in induction motor across multiple sensors with CNN-LSTM deep learning model
Ertargin, Merve; Yildirim, Ozal; Orhan, Ahmet
The utilization of monitoring sensors in machinery has led to the mainstream adoption of fault detection and diagnosis in time series data across various industrial applications. Deep learning techniques, specifically in constructing fault diagnosis models by extracting insights from historical equipment fault data, are receiving widespread attention as crucial tools in ensuring the safety and reliability of motor systems. In this study, a CNN-LSTM-based deep learning model is proposed for the detection of electric motor faults. Three distinct sets of accelerometer sensor data are provided as input to the model, enabling a comprehensive evaluation of its performance across various sensor configurations. The model demonstrated a remarkable capacity for generalization, achieving impressive accuracy rates of 99.96% for Accelerometer-1, 98.88% for Accelerometer-2, and 99.37% for Accelerometer-3. This underscores the robustness and adaptability of the proposed CNN-LSTM model in effectively detecting electric motor faults regardless of the specific accelerometer sensor employed.
AtıfScopus47OpenAlex38İncele - MakaleAçık Erişim2024Scopus SJRQ3The effects of biosynthesized silver nanoparticle on oxidative stress parameters in model organism Artemia salina (Linnaeus, 1758)
Ünal, İlkay; Ertürk Gürkan, Selin
Evaluation of the effects of nanomaterials in various habitats and living groups is increasing with in vitro and in vivo studies. This study aims to describe a biological procedure to synthesize silver nanoparticles using an extract of Marrubium astracanicum and to determine the aquatic environment’s oxidative stress on Artemia salina. Silver nanoparticle formation was visually observed with color change. Its structural properties, such as size, shape, morphology, and stability, were characterized by UV-Vis spectrophotometer, TEM, SEM, XRD, and DLS analyses. TEM image showed that the synthesized AgNPs have a size of between 20 and 50 nm. The effects of biosynthesized silver nanoparticles at different concentrations (control,0.2, 1, 5, 10, 25, and 50 mg/mL) and exposure times (24, 48 and 72 h) on total glutathione (GSH) and lipid peroxidation levels (MDA) were investigated on the Artemia salina organism, which is one of the most common saltwater organisms frequently used in ecotoxicity tests.
AtıfScopus4WoS2OpenAlex3İncele - MakaleAçık Erişim2024Scopus SJRQ1Late pleistocene glacial history of Mount Karadağ, SW Türkiye
Bayrakdar, Cihan; Çılğın, Zeynel; Sarış, Faize; Yeşilyurt, Serdar; Keserci, Ferhat; Büyükdeniz, Yusuf; Halis, Onur; Vockenhuber, Christof; Ivy-Ochs, Susan; Akçar, Naki
Glacial landforms in the southwestern part of the Anatolian Peninsula are found at lower elevations than the rest, suggesting that glaciers were present during the Late Pleistocene. Karadağ, located west of the Western Taurus Mountains, provides evidence of the climatic conditions that facilitated this extensive glaciation. It is characterized by numerous peaks exceeding 2300 m above sea level (asl), with the highest peak reaching 2418 m, making it the region's largest glaciation area. This high mountain mass is composed mainly of limestone and dolomite. This study focuses on the glacial landforms in Karadağ to reconstruct the Late Pleistocene glacial chronology and palaeoclimate of the Western Taurus Mountains. We employed detailed UAV photogrammetry, extensive fieldwork and mapping, surface exposure dating with cosmogenic 36Cl, meteorological measurements, palaeoglacier reconstruction, and palaeo-equilibrium line altitude (pELA) calculations. Karadağ, a topographic barrier to humid air masses from the Mediterranean Sea, ranks as the second wettest area in the Western Taurus Mountains. At a meteorological station we installed in Karadağ, an annual precipitation of 1700 mm or more was recorded, highlighting its significant precipitation. In Karadağ, we have identified two glacial valleys with a maximum length of 4.5 km and six cirques. The glaciers reached their maximum extent around 22.4 ± 2.8 ka during the Last Glacial Maximum (LGM), facilitated by the lowering of the pELA to 2090 m. During the LGM, the glaciers covered an area of approximately 3.5 km2 and reached a maximum thickness of about 140 m. Sample TRKR 10 at 2015 m probably belongs to the LGM period. Although a single sample does not conclude definitive conclusions, the presence of the moraine at its highest position indicates the maximum thickness of the glacier. Following the LGM, two more significant glacier advances occurred during the Lateglacial (15.5 ± 2.7 ka) and the Younger Dryas (12.4 ± 1.1 ka). During the late Pleistocene glaciations, and especially during the LGM, Karadağ probably received more precipitation than today, leading to the formation of glaciers at relatively lower elevations than on the Anatolian Peninsula.
AtıfScopus4OpenAlex10İncele - MakaleYayıncıda açık erişim2024Scopus SJRQ2Controlling of electro-optical properties of cobalt phthalocyanine formed single chain polymer: Sudan III and nanographene based its composites
Demirelli, Kadir; Barım, Esra; Tuncer, Hülya; Dere, Ayşegül; Canbay, Canan Aksu; Karaduman, Oktay; Al-Sehemi, Abdullah G.; Al-Ghamdif, Ahmed A.; Yakuphanoğlu, Fahretttin
The synthesis of poly[4-(4-vinylbenzyl)oxy)phthalonitrile-co-styrene] [P(VBOPN5 %-co-St)] was carried out by free radical polymerisation at 60 °C. The successful formation of a green coloured single-chain polymer molecule with the formation of cobalt phthalocyanine (SCP-CoPc) was performed at 140–150 °C in the presence of dilute cyclohexanol. The characterization of SCP-CoPc was confirmed by FT-IR and UV/vis spectroscopic techniques. The absorption filtration process of the SCP-CoPc polymer/Sudan III composite was investigated. The introduction of Sudan III into the SCP-CoPc polymer matric strongly affected the optical transmission spectrum of the composite films. The optical transmission measurements of the SCP-CoPc/Sudan III thin film show a high absorption in the visible region (400–800 nm). In the SCP-CoPc/Sudan III composites, the optical band gaps (Eg1 and Eg2) of each of its components has changed significantly. The Eg1 and Eg2 were found to be between 1.90 and 2.83 eV, respectively. Depending on the sudan III content, a wide range from 600 nm to 730 nm indicates complete absorption filtration. The dc electrical conductivity and dielectric behavior of the SCP-CoPc/Nanografene (NG) 6 wt% nanocomposite increased with increasing temperature. From the dc conductivity plot, the Ea values of I. and II. regions were found to be 0.75 eV and 0.27 eV, respectively and it was found that the calculated activation energy obeyed the Arrhenius relationship. The refractive index and the optical permittivity of SCP-CoPc/NG 6 wt% have been estimated.
AtıfScopus2OpenAlex3İncele - MakaleAçık Erişim2024Scopus SJRQ1A new hybrid mobile CNN approach for crosswalk recognition in autonomous vehicles
Doğan, Gürkan; Ergen, Burhan
While automobile transportation is increasing worldwide, it also negatively affects the safety of road users. Along with the neglect of traffic rules, pedestrians account for 22% of all highway traffic deaths. Millions of pedestrians suffer non-fatal injuries from these accidents. Most of these injuries and deaths occur at crosswalks, where the highway and pedestrians intersect. In this study, deep learning-based a new hybrid mobile CNN approaches are proposed to reduce injuries and deaths by automatically recognizing of crosswalks in autonomous vehicles. The first of these proposed approaches is the HMCNet approach, which is a hybrid model in which the MobileNetv3 and MNasNet CNN models are used together. This model achieves approximately 2% more accuracy than the peak performance of the lean used MobileNetv3 and MNasNet models. Another proposed approach is the FHMCNet approach, which increases the success of the HMCNet approach. In the FHMCNet approach, LSVC feature selection method and SVM classification method are used in addition to HMCNet. This approach increased the classification success of HMCNet by more than approximately 2%. Finally, the proposed FHMCNet offered approximately 3% more classification accuracy than state-of-the-art methods in the literature.
AtıfScopus10WoS7OpenAlex8İncele - MakaleAçık Erişim2024Scopus SJRQ3Effect of Insect Feed on Fish Growth: A Review
Chatha, Ahmad Manan Mustafa; Naz, Saima; Danabas, Durali; Gopal, N.; Central Institute of Fisheries Technology (CIFT), Matsyapuri P.O., Cochin, Kerala; Williams, M.J.; 17 Agnew Street, Aspley, QLD; Porter, M.; Kusakabe, K.; Asian Institute of Technology, School of Environment, Resources and Development, P.O. Box 4, Klong Luang, Pathumthani
The demand for sustainable and efficient protein sources in aquaculture has led to an increasing interest in exploring alternative feeds for fish. In recent years, insects have emerged as a promising option due to their nutritional value, economic viability, and potential to alleviate the environmental impact of traditional fish meals. This review critically examines the existing literature on the effect of insect feed on fish growth. Through a comprehensive analysis of relevant studies, we evaluate the performance of fish fed with insect-based diets compared to those fed with conventional feeds. The review encompasses various insect species, feed formulations, and fish species, providing insights into the factors influencing growth outcomes. Our findings highlight the potential benefits and challenges of incorporating insect-based feeds in fish farming practices, with implications for sustainable aquaculture and food security. By synthesizing current knowledge, this review aims to guide future research and decision-making processes for optimizing fish nutrition and production while promoting ecological sustainability.
AtıfScopus7OpenAlex5İncele - MakaleYalnız künye2024Scopus SJRQ1Modeling of Optimal Power Generation in Small Hydropower Plants
Kahraman, Gokhan
Small hydropower plants (SHPs) have gained international attention as a reliable and versatile renewable energy source. Unfortunately, this energy source is not used efficiently. This is because these systems utilize headwaters with lower water capacity called forebays instead of large water reservoirs like dams. Since this hinders the control of electricity generation, the headwater is either wasted before it can be converted into electricity or it is exhausted very quickly and electricity generation stops after a short time. The aim of this study is to prevent the loss of electricity generation through the efficient use of SHP headwater. For this purpose, a mathematical model was created based on two SHPs operating in tandem. The mathematical model obtained was analyzed, and forebay water level simulation graphs for electricity generation at water flowrates of 2000, 4000, 6000, and 8000 kg/h were obtained. With the help of the obtained graphs, critical wicket gate openings for maximum electricity generation at flowrates of 2000, 4000, 6000, and 8000 kg/h were calculated. The results of this study are applicable to all SHPs. These results are also promising in terms of optimizing the use of a renewable energy source.
AtıfScopus7WoS6OpenAlex6İncele - MakaleAçık Erişim2024Scopus SJRQ1Characteristics of Hozat apricot seed oil as a new source of oilseed
Aydin, Çağlar Mert
There has been an increase in apricot consumption due to its high bioactive and fiber content. However, the seed, inside part of the fruit, is considered as a food waste. In this study, potential usage of apricot seeds (bitter and sweet), that were cultivated in Hozat region- Tunceli, as an alternative oil source was evaluated. No comprehensive research has been undertaken to assess the seeds as an oil source before. In assessing its suitability for consumption, proximate composition of seed and physicochemical properties of the seeds’ oil had been determined. The proximate composition included the content of protein, ash, moisture, oil and the acidity as pH, in addition; iodine value, refractive index, nutritional quality, total phenolic content, antioxidant content, fatty acid composition and rheological properties of the oil were determined. Also, the effect of variety on them was examined. Overall, oil content was found to be the major component of the seed, thus the seed is good enough to be used as an oil source. Five different fatty acids were identified in the oil, that produced from the seed. These were palmitic, heptadecanoic, oleic, linoleic and linolenic acid. The oil had a refractive index between 1.4617 and 1.4628, iodine value between 100.47 and 102.11 gms, total phenolic content between 0.83 and 1.29 mg GAE g−1 oil, antioxidant activity between 11.21 and 11.60 mg TE g−1 oil for DPPH assay and 7.92–8.20 mg TE g−1 oil for ABTS assay, and apparent viscosity of 0.04 Pa.s. Moreover, viscous flow tests showed that the oil has a Newtonian flow behavior, and the nutritional indexes, that include unsaturated, atherogenicity, thrombogenicity and hypocholesterolemic/ hypercholesterolemic ratio, indicated that the oil is good enough for consumption as an oil source. The variety was found to have a significant effect on total phenolic content, antioxidant activity and refractive index of the oil, that was produced from apricot seed.
AtıfScopus4WoS4OpenAlex4İncele - MakaleYalnız künye2024Scopus SJRQ2Seasonal Monitoring of Heavy Metal Pollution in Water and Zebra Mussels Dreissena polymorpha as a Potential Bioindicator Species from Lake Habitat
Kutluyer Kocabaş, Filiz; Başaran, Ertuğrul; Kocabaş, Mehmet
In aquatic ecosystem, metal pollution is an important environmental hazard. Mussels as a bioindicator species are often used for assessment the presence of potentially toxic metals. Hence, the present study aimed to assess the effect of seasonal variations on some heavy metals (Cd, Cr, Pb, As, Zn and Cu) accumulation in water and Dreissena polymorpha from lake habitat. Our result indicated that Zn accumulated at a very high level in the zebra mussels while As accumulated at a high level in water samples. Seasonal variations significantly affected Cu concentration in the water samples (P < 0.05) while Cr concentration in the mussel samples was significantly affected by seasonal variations (P < 0.05). According to the water analysis, mean concentrations of metals are below the maximum limits established by the World Health Organization and USEPA, except As. Overall, our data emphasize anthropogenic pollution in the Turkish aquatic environment and confirm the use of D. polymorpha as a prospective biomonitor for metal polluted sites’.
AtıfScopus3WoS2OpenAlex4
İncele - DüzeltmeYalnız künye2024Scopus SJRQ1Retraction notice to “Cooling of non-sloped, positively sloped, and negatively sloped arrangements of Li-ion batteries with a phase change material connected to a solar system” [J. Energy Storage 52 Part B (2022) 104808] (Journal of Energy Storage (2022) 52(PB), (S2352152X22008179), (10.1016/j.est.2022.104808))
Akkurt, Nevzat; Aghakhani, S.; Mahmoud, Mustafa Z.; Abdelrahman, Anas
This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/policies/article-withdrawal). Please note that an Expression of Concern has previously been published to alert readers to an ongoing investigation into this paper. This retraction supersedes the Expression of Concern. This article has been retracted at the request of the editor. In investigating concerns brought up regarding the article, the editor reached out to the authors for an explanation. Furthermore, the editor discovered suspicious changes in authorship between the original submission and the revised version of this paper. In summary, the author names Nevzat Akkurt (new first author), Mustafa Z. Mahmoud and Anas Abdelrahman were added to the revised paper without explanation and without the exceptional approval by the editor, which is contrary to the journal policy on changes to authorship. The authors failed to provide a satisfactory explanation to the above points. The editor therefore feels that the findings of the manuscript cannot be relied upon and that the article needs to be retracted.
- MakaleYalnız künye2024Scopus SJRQ2Process optimization and modeling of Pb(II) ions adsorption on a new and reusable biocomposite material using experimental design approach
Ince, Muharrem; Kaplan Ince, Olcay; Alp Kavlo, Hevidar
This research paper aimed to establish the optimal conditions for lead (Pb(II)) ions from industrial wastewater (IW) using response surface methodology and central composite design (CCD) approach. A fixed-bed column study was designed by using a novel and reusable biocomposite material, Amanita vaginata (A. vaginata) immobilized on Amberlite XAD-4 resin (A&XAD-4@AV), to find out biosorption behavior of Pb(II) ions. Various experimental variables such as optimum pH value, biocomposite material amount, flow rate, and Pb(II) ions initial concentration were investigated, which significantly affected the Pb(II) ions removal efficiency. The maximum Pb(II) removal efficiency of A&XAD-4@AV biocomposite material was determined as 11.2 mg g−1 under optimum conditions. The reusability of A&XAD-4@AV biocomposite material was found to be suitable. For checking model adequacy, a regression model was derived using CCD to predict the responses and analysis of variance (ANOVA) and lack of fit test was performed. It was observed that the quadratic model, which was controlled and proposed, originated from experimental design data. The ANOVA showed a high coefficient of determination (R2 = 0.9896, R2Adj = 0.9800, R2Pred = 0.9633). Finally, developed and optimized method was applied effectively to wastewater for determining Pb(II) ions levels. The current study indicated that the prepared A&XAD-4@AV is an efficient material to remove of Pb(II) ions from IW.
AtıfScopus1WoS1OpenAlex1İncele - MakaleYayıncıda açık erişim2024Scopus SJRQ2Selenium Inhibitor Coating on NiTi Shape Memory Alloys by Using Thermal Evaporation System
Kök, Mediha; Kanca, Muhammed Sait; Say, Yakup; Saydam, Sinan; Dağdelen, Fethi; Qader, Ibrahim Nazem
NiTi-based memory alloys are often used as intracorporeal implant materials because of their superelasticity and shape memory properties. However, over time, the release of nickel from the NiTi alloy into the body becomes unfavorable; therefore, studies should be conducted to reduce the negative impact of nickel leakage. In this study, the biocompatible selenium element was used to coat NiTi alloys with different thicknesses. The coating process was performed using the thermal evaporation technique. Scanning electron microscopy-Energy Dispersive X-ray Analysis measurements revealed that the surfaces of the samples were well covered. Also, the atomic force microscope device determined the surface roughness of the alloys. The roughness of the surface increased after the coating process. The Tafel test was accomplished to determine the biocompatibility of the coated and uncoated alloys in an artificial body fluid. The corrosion test reveals that Se-coated NiTi alloys have high corrosion resistance.
- MakaleAçık Erişim2024Scopus SJRQ2Zr and V-doped effect on Martensitic transformations and magnetic properties of NiMnIn shape memory alloy
Taşgın, Yahya; Kanca, M. Sait; Kök, Mediha; Öner, Ecem Özen; Güler, Ömer
In this study, the elements vanadium (V) and zirconium (Zr) were doped separately as a fourth element to the ternary NiMnIn Heusler magnetic shape memory alloy and the alloys were produced as ingots by arc-melting method. The shape memory properties, microstructures, magnetic and microstructural changes of these new alloys were investigated in detail. The vanadium (V) and zirconium (Zr) elements doped into the alloy caused a decrease in the transformation temperature values of the alloy, but did not cause a significant change in its magnetic properties. The master sample, which has low hysteresis, undergoes a phase transition from the martensite phase to the austenite phase due to an increase in the nucleation of austenite phases at the twinning boundaries. Here, the vanadium and zirconium doping of the alloy caused an increase in the strength and ductility values of the alloy and this caused the formation of the second phase. Due to the increase of this phase formation in the alloy, it can be said that there is a slight decrease in the shape retention of the alloy.
AtıfScopus3WoS3OpenAlex3İncele - MakaleYalnız künye2024Scopus SJRQ1Aerodynamic drag improvements on a circular cylinder using passive Venturi actuators
Firat, Erhan; Seyhan, Mehmet; Ozkan, Gokturk M.
Scale-adaptive simulations (SAS) of three-dimensional flow around a circular cylinder fitted with a passive version of a novel flow control method (passive Venturi actuator, PVA) are performed at a diameter-based Reynolds number of Re = 28 000. The PVA consists of one or more narrow slits located at the top and/or bottom sides of the cylinder that connected to the throat of the axial Venturi slit in this cylinder. The main purpose of the study is to investigate the influence of divergence angle and narrow slit location relative to the axial Venturi slit on the aerodynamic performance of the cylinder. To this end, four models were designed with various PVAs. Additional models, a plain cylinder (unmodified model) and a cylinder fitted with an axial Venturi slit (model without a narrow slit), were also used for quantitative comparison. SAS predicts that an additional 5% reduction in the time-averaged drag coefficient, ⟨ C D ⟩ , was observed when two narrow slits located on the surface at an angle of ±80° from the front stagnation line were fitted to the cylinder with an axial Venturi slit. Reducing the divergence angle of the PVA leads to improvements in ⟨ C D ⟩ and root mean square of fluctuating force coefficients, C D − rms and C L − rms . It is found that a cylinder with a PVA that has two narrow slits and a divergence angle of 6° can produce a 28.6% reduction in ⟨ C D ⟩ , a 58.5% reduction in C D − rms , and an 81.2% reduction in C L − rms , when compared to the plain cylinder.
AtıfScopus4OpenAlex4İncele - MakaleAçık Erişim2024Scopus SJRQ2Mattiastrum pulumurense (Cynoglossinae, Boraginaceae), a new endemic species from Türkiye
Doğru Koca, Aslı; Gökmen, Mustafa; Yilmaz, Gülderen; Paksoy, Mehmet Yavuz
A new species, Mattiastrum pulumurense, has been described from Tunceli in eastern Türkiye. It is generally distinguished from other species (except M. racemosum var. scabridum) by a sparsely hairy or glabrescent above-ground part. It is most similar morphologically to M. longipes, M. calycinum, and Paracaryum hedgei (P. hedgei is potentially a member of the genus Mattiastrum). However, it differs from M. longipes and M. calycinum by its 3–3.5-mm-long and linear lanceolate scales, 2.5–4.5-mm-long anthers, and 10–15-mm-long styles; it differs from Paracaryum hedgei by its 3–3.5-mm-long scales, 2.5–4.5-mm-long anthers. In addition, this new species differs from M. racemosum var. scabridum by having 3–3.5-mm-long scales and no scale appendages. A description of the new species, an illustration, a comparative Table of morphological characters, detailed photographs, and a distribution map of the new species together with adjacent species were provided. In addition, the evolutionary relationships of these species were calculated using both Bayesian inference and maximum likelihood analyses based on the ribosomal internal transcribed spacer (ITS1-5.8S-ITS2) and combined chloroplast data set (rps16 and trnL genes, trnL-trnF intergenic spacer). According to the phylogeny-based combined chloroplast data set, both populations of Mattiastrum pulumurense generate a monophyletic clade and are closely related to M. longipes, P. hedgei, and M. calycinum. According to ITS-based phylogeny, Mattiastrum pulumurense is closely related to Rindera tetraspis, which is seen in the paraphyletic and nested genera Mattiastrum-Paracaryum-Rindera.
AtıfScopus1
İncele - MakaleYalnız künye2024Scopus SJRQ2Factors Affecting the Setting Times of Pumice Based Alkali-Activated Hybrid Cements
Balun, Bilal; Karataş, Mehmet
The environmental impacts of ordinary Portland cement (OPC) production have led researchers to produce alternative binders. Binders with aluminosilicate structure, such as pumice, can be used to produce one of these alternatives, alkali-activated cements. In addition, alkali-activated hybrid cements have become a type of material that combines the positive aspects of geopolymers and Portland cement. Especially in the activation of low CaO containing materials such as pumice with alkalis, the use of a small amount of OPC ensures that the alkali-activated materials can both be produced under ambient conditions and improves its strength properties. In this study, setting times of pumiced based alkali-activated hybrid cements were evaluated based on OPC amount (0%, 5%, 10%, 15% and 20%), alkaline solution/binder ratio (0.47, 0.50 and 0.53) and sodium silicate/potassium hydroxide (1, 2 and 3) ratio. In experiments carried out under ambient conditions, the silica module (2.0) of the sodium silicate solution was kept constant. As a result of the experimental studies, the increase in the OPC amount and the sodium silicate ratio shortened the setting times of the pumiced based alkali-activated hybrid materials while the alkali solution/binder ratio increased the setting times. It was determined that the factor most affects the setting times was the OPC amount. The setting time of the OPC-free pumice-based alkali-activated binders without OPC takes more than one day. As a result, increasing the amount of OPC up to 20% significantly reduced the setting times. A decreasing trend was observed in compressive strengths with increasing setting times.
AtıfScopus5WoS4OpenAlex5İncele - MakaleYalnız künye2024Scopus SJRQ3Development of a novel rare earth element doped chitosan-graft-poly(hydroxyethyl methacrylate) composite for biomedical applications: synthesis, characterization, drug delivery, and antibacterial properties
Gürler, N.; Torǧut, G.; Yazdıç, F.C.; Karaman, A.; Karaaslan Ayhan, N.
The films of chitosan-graft-poly(hydroxyethyl methacrylate) polymer (Ch—g-poly(HEMA)) doped with the rare earth element (REE) lanthanum (La content of 0, 0.2, 0.4, and 0.8 wt.%) were fabricated. The films were characterized by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS), thermogravimetric analysis (TGA), and powder X-ray diffraction (XRD) analysis. The films obtained were loaded with a model drug tetracycline by freezing/thawing method. The cumulative drug release properties of tetracycline were investigated. The release of tetracycline from the polymer matrix was carried out in phosphate-buffered saline (PBS) buffer (pH 7.4) at 37 °C. It was found that the REE-doped composite films had a retarding effect on tetracycline drug release compared to that of the undoped film. All tested composites regardless of the REE dopant content were found to be active against three Gram-positive and three Gram-negative bacterial strains used to assess the antimicrobial properties of the polymer composites. These findings demonstrated that lanthanum and tetracycline have a high affinity for the Ch—g-poly(HEMA) polymer and suggested a synergistic effect in the polymer—lanthanum—tetracycline system. The La3+-doped Ch—g-poly(HEMA) composite film can be used as drug carrier system in the biomedical field.
AtıfScopus4WoS4OpenAlex3İncele