Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Güler, Ömer(32)
- Akkurt, Nevzat(27)
- Tekin, H.O.(27)
- ALMisned, Ghada(24)
- Gul, Muhammet(20)
- Yucesan, Melih(14)
- Xu, Qian(12)
- Baykal, Duygu Sen(11)
- Güler, Seval Hale(11)
- Taşgın, Yahya(10)
- Kavaz, E.(9)
- Kilic, G.(8)
- Zengin, Gokhan(8)
- Durmus, Hasan(7)
- Guler, Omer(7)
- Xiong, Yaxuan(7)
- Yılmaz, Demet(7)
- Özkul, İskender(7)
- Yayla, Nihal(6)
- Zhang, Hui(6)
- Alkarrani, Hessa(5)
- Baloglu, Ulas Baran(5)
- Celik, Erkan(5)
- Du, Yanping(5)
- Ilik, E.(5)
- Kanca, M. Sait(5)
- Kök, Mediha(5)
- Mahomoodally, Mohamad Fawzi(5)
- Ortiz-Barrios, Miguel(5)
- Qiang, Yujie(5)
- Yang, Gang(5)
- Zakaly, Hesham M.H.(5)
- Aghakhani, S.(4)
- Basgoz, Oykum(4)
- Birdogan, Selcuk(4)
- Caprioli, Giovanni(4)
- Etli, Serkan(4)
- Guler, Seval Hale(4)
- Kahraman, Gökhan(4)
- Liu, Lin(4)
Yayınlar
- MakaleYalnız künye2023Scopus SJRQ1Heat loss optimization and economic evaluation of a new fourth generation district heating triple pipe system
Chen, Xingli; Ren, Ling; Zheng, Qiang; Yang, Gang; Akkurt, Nevzat; Liu, Lin; Liu, Zhiwei; Qiang, Yujie; Yang, Huachao; Xu, Qian
In response to the heat loss caused by the temperature difference between the heating pipes and external environment during the pipe transportation, heat contradiction between the total heat loss of the piping system and heat transfer between tubes, as well as economic balance between the cost of heat loss and cost of material loss. Based on TOTS (Two-supply/One-return, triple pipe structure) heat loss theory of the fourth-generation district heating system, this paper optimizes structure of pipes by setting dimensionless characteristic parameters θ and β. Finally, a mathematical model is proposed to calculate economic efficiency of pipeline network by considering the cost of initial construction material loss and operation heat loss of the pipe. Results show that, from energy perspective, comprehensive heat as system energy consumption evaluation index is positively correlated with θ, decreases first and then increases as β increases. Total heat loss of system dominates comprehensive heat. Lowest comprehensive heat of system is 18.12 w/m for θ of 0.1945 and β of 0.0739. From economic perspective, total system loss cost as system economic evaluation index is positively correlated with both θ and β. Total system heat loss cost dominates total system loss cost. Lowest total system loss cost is $29.39/m for θ of 0.1945 and β of 0.0509.
AtıfScopus16OpenAlex20
İncele - MakaleYalnız künye2023Scopus SJRQ1Latent heat thermal energy storage in a shell-tube design: Impact of metal foam inserts in the heat transfer fluid side
Ghalambaz, Mehdi; Sheremet, Mikhail; Raizah, Zehba; Akkurt, Nevzat; Ghalambaz, Mohammad
The improvement of heat transfer in latent heat thermal energy storage (LHTES) system is a crucial task. In the current study, the impact of diverse metal foam (MF) layer arrangements on heat transfer fluid (HTF) within a shell-tube LHTES is explored. Six distinct cases (A-F) with varied MF coverage percentages and layer dimensions were assessed. The local thermal non-equilibrium model was utilized to take into account the PCM and MF temperatures. The finite element method was used for solving the partial differential equations. The impact of MF configurations and inlet pressures (250 Pa, 500 Pa, and 750 Pa) on the thermal energy storage/release was addressed. Cases A-C, featuring a 50 % MF concentration, exhibit shorter melting times than Cases D–F, with decreasing MF concentrations. A higher MF concentration improves the melting process due to increased thermal conductivity and lower thermal resistance on the HTF side. Cases D–F, with a centralized MF layer and decreasing concentrations from 25 % to 6.25 %, display progressively shorter melting times, suggesting that a lower MF concentration leads to more efficient melting. Solidification times also decrease with increasing inlet pressures across all cases. Reynolds numbers, influenced by average HTF tube outlet velocity, vary substantially across cases and inlet pressure differences. Cases A-C demonstrate similar Reynolds numbers for each inlet pressure difference, while Cases D–F show a more pronounced increase in Reynolds numbers as the MF layer is reduced and flow resistance drops. Cases A (50 % MF layer) and F (6.5 % MF layer) provide the quickest charging and discharging times due to their unique combination of MF layer properties and inlet pressures. The study highlights the need to consider MF layer composition and inlet pressure when designing optimal LHTES systems for efficient energy storage/release.
AtıfScopus11WoS10OpenAlex11İncele - MakaleYalnız künye2023Scopus SJRQ1An integrated hybrid MCDM approach to evaluate countries’ COVID-19 risks
Mete, Suleyman; Yucesan, Melih; Gul, Muhammet; Ozceylan, Eren
To enable planning and early reaction efforts, it is important to identify the nations most at risk from COVID-19's health and humanitarian effects, which could exceed present national response capabilities. INFORM COVID-19 Risk Index developed by European Commission is one of the initiatives to meet the aforementioned need. However, the Index has 40 conflicting and comprehensive indicators (e.g., health system capacity, hygiene, vulnerability) and different countries that lead to a need for multicriteria decision-making (MCDM) approaches. This paper offers an integrated MCDM approach with two phases to re-assess the countries' COVID-19 risks based on INFORM COVID-19 Risk Index. In the first phase, the 40 indicators are prioritized using the Entropy-based multi-choice best-worst method (MC-BWM) to provide multiple viewpoints for the preferences values. In the second phase, 29 countries from different geographical regions are ranked using the COPRAS (Complex Proportional Assessment) method. Applying these three methods together on the COVID-19 risk assessment of countries is the most significant novelty for the relevant literature. The proposed approach has undergone a thorough comparative evaluation with the released INFORM COVID-19 Risk Index, and recommendations are provided based on different scenario analyses.
AtıfScopus21WoS16OpenAlex18İncele - MakaleAçık Erişim2023Scopus SJRQ1Detailed investigation of zinc coating behaviours in various deep eutectic solvents
Cihangir, Salih; Ryder, Karl S.; Unal, Asuman
Determining the optimum conditions of a metal coating is significant for its possible applications in many fields. The present work described the electrodynamic process of zinc coating from six different deep eutectic solvents (DESs), especially type-III DES systems prepared with a quaternary ammonium salt and hydrogen bond type. Non-reversible processes without oxidation were found in DES systems prepared with choline chloride and zinc nitrate salts, and also, propylene glycol and zinc nitrate salts, termed as type-II and type-IV, respectively. The most attracted type-III DES prepared by a mixture of 1 molar choline chloride and 2 molar ethylene glycols, commercially known as Ethaline (E200), were examined for its electronucleation and possible reactions for zinc electrodeposition. For the first time, the Pt working electrode was investigated under high-resolution optical microscopy to visualize the in-situ morphology change during oxidation and reduction in E200. Furthermore, the morphological change during the anodic dissolution of zinc was also investigated in situ under a high-resolution microscope. It was found that insoluble species forming during anodic dissolution blocks the surface. Bulk electrolysis was performed in these solvents to investigate the formed zinc nucleates' morphological differences. XRD analysis was performed to differentiate the crystal planes of each deposition obtained from six DESs. It was found that the type-II and type-IV DESs consisting of zinc nitrates revealed zinc hydroxy nitrate dominated zinc deposition, which can be helpful in various applications.
AtıfScopus14WoS11OpenAlex15İncele - MakaleAçık Erişim2023Scopus SJRQ1Case study of thermal and solutal aspects on non-Newtonian Prandtl hybrid nanofluid flowing via stretchable sheet: Multiple slip solution
Shamshuddin, MD.; Raizah, Zehba; Akkurt, Nevzat; Patil, Vishwambhar S.; Eldin, Sayed M.
The effect of multiple slip boundary conditions is one more important physical parameter on the flow investigation and have been studied in this analysis. Further, the effect of Ohmic heating and varying chemical reaction on non-Newtonian Prandtl hybrid nanofluid with water based nanofluids to an extending of leading edge was also investigated to this current analysis. An inclined magnetic field is introduced to fluid flow to regulate the fluid stream. Hybrid nanomaterial is synthesized by the dispersion of Cu and Cofe2O4 nanoparticles in Prandtl fluid. All chemical science specifications of nanofluid are measured as constant. Due to the nanofluid particles motion, the fluid concentration is inspected underneath chemical implications. A mathematical model is developed by assuming the flow as incompressible and purely cartesian coordinate system and appropriate non-dimensional variables are introduced for problem simplifications and dimensional analysis. The scheme for semi analytical study named Homotopy Analysis Method (HAM) is implied to get solutions to the equations. The procedure is then displayed pictorially where fluid velocity, temperature and concertation against various pertinent parameters are examined. It was found that, the Concentration field profiles have been shown to deteriorate because molecule diffusivity reduces as the chemical reaction parameter rises in both cases. In order to maintain thermal balance management in tiny heat density equipment and gadgets, current research may also be helpful in enhancing the thermal efficiency of heat exchangers.
AtıfScopus41WoS38OpenAlex44İncele - MakaleYalnız künye2022Scopus SJRQ1Numerical evaluation of the coupled/uncoupled effectiveness of a fluid-solid-thermal multi-field model for a long-distance energy transmission pipeline
Wang, Kang; Xie, Kai; Zhang, Hui; Qiang, Yujie; Du, Yanping; Xiong, Yaxuan; Zou, Zhenwei; Zhang, Mingbao; Zhong, Liqiong; Akkurt, Nevzat
As the main component of energy transmission, long-distance energy transmission pipeline (LETP), whose safety problem is becoming more and more prominent with the development of the oil and gas transportation industry, is susceptible to the traffic loading, temperature loading, pressure loading and other loadings. In this paper, the mechanical characteristics of LETP under the interaction of temperature loading and pressure loading are investigated. Based on the theory of multi-field coupling, the mathematical model of fluid-solid-thermal coupling of fluid-filled pipelines under the combined effect of temperature and pressure loadings is established and verified. Meanwhile, an equivalent model is proposed to accurately calculate the stress of any pipeline segment in LETP. The results show that the coupling of temperature loading and the pressure loading is significantly affected by the end-side constraints of the pipelines. For strong end-side constraint, the coupling effect of temperature and pressure loadings has a significant effect on the calculated equivalent stress. The difference between the stress solution under coupling effect and decoupling effect is above 30 MPa. However, for weak end-side constraints, the error is within 10 MPa. The equivalent stress can be approximated by the decoupling solution instead of the coupling solution.
AtıfScopus15OpenAlex15İncele - MakaleAçık Erişim2022Scopus SJRQ1Evaluation of the mechanical properties and durability of self-compacting alkali-activated mortar made from boron waste and granulated blast furnace slag
Yön, Merve Şahin; Karataş, Mehmet
The production of high-strength alkali-activated mortar and concrete by using waste materials instead of cement in order to reduce the amount of carbon dioxide released to nature in cement production is an important study that attracts the attention of researchers. In this study, self-compacting alkali-activated mortar samples were produced using boron waste (BW) and granulated blast furnace slag (GBFS). Prismatic samples of 40 × 40 × 160 mm and cubes of 50 × 50 × 50 mm were produced, in which 0%, 5%, 10%, 15%, 20%, 25% of BW were used. To achieve self-compacting alkali-activated mortar (SCAAM) slump-flow test method was conducted by per The European Federation of Specialist Construction Chemicals and Concrete Systems (EFNARC) guidelines. The samples prepared using Na2SiO3 (NS)/NaOH (NH) = 3.0 were exposed to oven curing at 60 °C and 100 °C for 3 days. The flexural and compressive strength (CS) values of 3, 28 and 90 days were obtained for the samples whose curing period was completed. According to the mechanical strength results, influence of capillary water absorption, porosity, water absorption and density and freeze-thaw from durability tests were carried out. After experimental tests, Scanning Electron Microscope (SEM) and Energy-dispersive X-ray Spectroscopy (EDS) images were utilized to determine microstructures of the samples. As a result of the study, it was determined that the highest strengths were obtained at the curing temperature of 60 °C. Also, it was seen that mechanical strengths and durability decreased with the increase in the BW ratio in the mixtures.
AtıfScopus31WoS28OpenAlex33İncele - MakaleYalnız künye2022Scopus SJRQ1A novel prediction model for durability properties of concrete modified with steel fiber and Silica Fume by using Hybridized GRELM
Cemalgil, Selim; Gül, Enes; Onat, Onur; Yılmaz Aruntaş, Hüseyin
The service life performance of conventional and modified concrete subjected to harsh climatic condition environment is directly related to durability properties of concrete like abrasion, freezing and thawing cycles. These properties are critical issues that should be predicted before performing experimental test. On this basis, the basic purpose of this paper is to predict the abrasion loss, freezing and thawing properties of concrete modified with silica fume (SF) and steel fiber (SFb) by using mix design and additional properties. From this point of view, a conducted experimental study was selected as a case study. In the control concrete (CC) mixtures, Portland cement, crushed stone aggregate, and superplasticizer (SP) were used in the selected experimental study. SP in concrete mixtures was used in the amounts of 1.0%, 1.5%, and 2.0% by weight of cement, and so modified concrete was produced with and without SFb according to the target strength of C25. Furthermore, SF and SFb were used in different amounts to modify the concrete. The SF was replaced with cement in the amounts of 7.5%, 10.0%, and 15.0%. In total, 16 different mix designs were prepared with different SP and SF ratios. In addition, SFb was added to all mixtures of designed concrete at a constant amount of 65 kg/m3. Additionally, a 16-mix design was prepared with SFb. Cumulatively, 32 different mix designs were prepared for the experimental study. Tests on the fresh, hardened, and life-cycle performance properties of the concrete were conducted. As for the metaheuristic part of this study, on the basis of the available experimental data, life-cycle performance parameters of the concrete modified with SF and SFb are predicted by using single and hybrid generalized extreme learning machine methods. Eight different data sets were generated with gradually extended input data. Two different outputs were considered: abrasion resistance (AL) and freezing/thawing (FT). Particle Swarm Optimization (PSO) and Grey Wolf Optimization (GWO) algorithms were used to produce binary and ternary hybrid methods. Four different models were proposed as listed: single use of Generalized Extreme Learning Machine (GRELM), binary use of GRELM-PSO, and GRELM-GWO. Finally, PSO and GWO were hybridized and integrated into GRELM. Two quality indicators, namely Root Mean Square Error (RMSE) and correlation of determination (R2), were considered to see the performance of the prediction. The results showed that the proposed ternary prediction model composed of GRELM-PSO-GWO provided more accurate results in all sets from 74% to 91% by extending input parameters, even if complicated parameters are inserted in as an input to the data set.
AtıfScopus28WoS22OpenAlex25İncele - MakaleAçık Erişim2022Scopus SJRQ2Effects of silver/selenium/chitosan doped hydroxyapatite coatings on REX-734 alloy: Morphology, antibacterial activity, and cell viability
Aksakal, B.; Say, Y.; Sinirlioglu, Z.A.
The goal of this study was to improve the antibacterial activity and cell viability of the Rex-734 alloy in biomedical applications. Various biocomposite coatings, such as single-layer hydroxyapatite (HAp), HAp/silver(Ag), and HAp/selenium(Se)/chitosan(Chit), were applied to Rex-734 alloy at various film thicknesses. The surface coatings were characterized by scanning electron microscopy, SEM, EDX, XRD and coating thickness and hardness of surface coatings were measured. The in vitro antibacterial activities of the coated and uncoated substrates were tested against Esherichia coli JM 103 and Staphylococcus aureus ATCC29293. In vitro cell–material interactions using Saos-2 osteoblast cells were characterized by the 3-(4,5-dimethylthiazol2-yl)− 2,5-diphenyltetrazolium bromide (MTT) assay for cell viability. The post-coating sintering parameters were shown to have a significant effect on the surface morphology. When compared to single HAp and HAp/Ag coatings, Se and Chit additions to HAp powders revealed good crack-free coating surfaces. Crack-free coating morphologies were achieved with a sintering speed of 3 °C/min. While single-HA coatings had an antimicrobial efficiency of 83% against E. coli, this value increased to 94% with Ag additive and to 85% with Se additive. Similarly, Ag and Se additives improved HAp's antimicrobial efficiency against Staphylococcus aureus. Cell viability decreased in the HAp/Ag coating at 86.5% and 90.93%, but increased significantly (p < 0.05) in the HA/Se-Chit coating at 137,43% and 158.23% at the end of the first and seventh days of incubation, respectively. The addition of Ag/Se/Chit to HAp increased the viability of the Rex-734 cells. Furthermore, it was revealed that the HAp-doped Se/Chit duplex biocomposite coating groups increased bone cell viability at much higher rates than the single-layer HAp coatings.
AtıfScopus12WoS8OpenAlex8İncele - MakaleAçık Erişim2022Scopus SJRQ1A fuzzy hybrid decision-making framework for increasing the hospital disaster preparedness: The colombian case
Ortiz-Barrios, Miguel; Gul, Muhammet; Yucesan, Melih; Alfaro-Sarmiento, Isaac; Navarro-Jiménez, Eduardo; Jiménez-Delgado, Genett
The recent increase in the number of disasters over the world has once again brought to the agenda the question of preparedness of the hospitals, which are the most necessary units of healthcare pillar to resist these disasters. The COVID-19 epidemic disease, which has affected the whole world, has caused a large number of people to die in some countries simply because of the inadequate and incomplete planning and lack of readiness of hospitals. For this reason, determining the disaster preparedness level of hospitals is an important issue that needs to be studied and it is important in terms of disaster damage reduction. In this study, a fuzzy hybrid decision-making framework is proposed to assess hospital disaster preparedness. The framework covers three important decision-making methods. For the first phase, Intuitionistic Fuzzy Analytic Hierarchy Process (IF-AHP) is used to assign relative weights for several disaster preparedness criteria considering uncertainty. Secondly, Intuitionistic Fuzzy Decision Making Trial and Evaluation Laboratory (IF-DEMATEL) is applied to identify interrelations among these criteria and feedback. Finally, via the VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) method, priorities of hospitals regarding disaster readiness are obtained. A case study involving the participation of 10 Colombian tertiary hospitals is carried out to show the applicability of this fuzzy hybrid approach.
AtıfScopus27WoS24OpenAlex34
İncele - MakaleAçık Erişim2022Scopus SJRQ1An interval type-2 fuzzy enhanced best–worst method for the evaluation of ship diesel generator failures
Yucesan, Melih; Başhan, Veysi; Demirel, Hakan; Gul, Muhammet
The environmental destruction in our century necessitates the implementation of more safety-based rules and the strict implementation of failure analysis, especially in the maritime sector. The generator system, considered the ship's powerhouse, is expected to be ready and well-maintained for efficient and safe operations. This study proposes a new methodology to analyze ship generator failures. This method includes a version of the best-worst multi-criteria decision-making method enriched with interval type-2 fuzzy logic (IT2FE-BWM). Enrichment with interval type-2 fuzzy numbers shows that a parameter about how much the decision-maker trusts the pairwise comparisons are added to the model. Thus, a more sensitive methodology has been proposed for the confidence of the maritime sector evaluators. A solid decision mechanism has been developed to prioritize generator failures. In addition, a comparison study with some other BWM derivatives and a creative sensitivity analysis were added to this study and its robustness was tested.
AtıfScopus25OpenAlex24İncele - MakaleYalnız künye2022Scopus SJRQ1Heat and mass transfer mechanism and control strategy of clean low carbon combustion technology in the novel-type coke oven flue with MILD combustion
Xu, Qian; Shen, Meng; Xie, Kai; Zhang, Hui; Akkurt, Nevzat; Wang, Jiulong; Xiong, Yaxuan; Shi, Kejian; Chen, Xingli; Lv, Qian
In the field of emission reduction, considering the limitations of single clean combustion technology and joint control of carbon emission, the application of Technology of Mixed-Gas (TMG), Technology of Low-calorific Value Gas (TLVG) and Technology of Low Oxygen Combustion (TLOC) in the Novel-type Coke Oven Flue with MILD Combustion (MILD-NCOF) was realized. By adjusting the ratio of coke oven gas to blast furnace gas (α), the ratio of flue gas to gas (β) and the ratio of flue gas to air (γ), the heat and mass transfer mechanism of combustion process in MILD-NCOF was researched, the dual emission control system and the regulation strategy of pollutant and carbon emissions were established. The results showed that with the increase of α, β and γ, the fluidity of gas and the reaction rate of combustible components in the fire path were improved, the heat and mass transfer was enhanced, and the effect of dual emission reduction of pollutants and carbon emissions was improved. When the mixing ratio α was 0.6, Tave was reached at 1594.93 K. The NOx concentration at the outlet was 116.34 mg/m3, and the sum of the molar concentrations of CO and CO2 at the outlet was reduced to 1.440 × 10−1. When the mixing ratio β was 2.4, Tave was reached at 1518.73 K, the NOx concentration at the outlet was 128.42 mg/m3, and the sum of the molar concentrations of CO and CO2 at the outlet was 1.127 × 10−1. When the mixing ratio γ was 0.6, Tave was reached at 1627.28 K, the NOx concentration at the outlet was 142.73 mg/m3, and the sum of the molar concentrations of CO and CO2 was reduced to 1.128 × 10−1, which could meet the dual standards of clean production and low-carbon environmental protection of MILD-NCOF.
AtıfScopus30OpenAlex36İncele - MakaleYalnız künye2022Scopus SJRQ1Heat transfer performance by forced convection of microencapsulated phase change material-latent functional thermal fluid flowing in a mini-channels heat sink
Xu, Qian; Zhu, Lidong; Yan, Xinyu; Yang, Jingbin; Wang, Zhaoxiao; Liu, DingHai; Yang, Gang; Chen, Xingli; Akkurt, Nevzat; Liu, Lin
Conventional single-phase coolants have not been able to meet the high cooling requirements of electronic devices. Microencapsulated phase change material-latent functional thermal fluid (MPCM-LFTF), a solid–liquid two-phase cooling medium, has the dual advantages of active liquid cooling and passive phase change material cooling. However, it also increases the power consumption in the mini-channels, and the cooling efficiency of MPCM-LFTF in practical applications needs to be further studied. A new MPCM-LFTF was prepared by paraffin melamine resin MPCM and base fluid (absolute ethanol and deionized water) in this work. The heat transfer performance and hydrodynamic properties were investigated using the dimensionless wall temperature and friction factor, respectively. The efficiency factor was introduced to evaluate the cooling efficiency of MPCM-LFTF in mini-channels. The experimental results showed that the addition of MPCM increased the viscosity of MPCM-LFTF, which increased the friction factor. MPCM-LFTF with a mass fraction of 15 % had the best effect of temperature control and reduced the dimensionless wall temperature by 40.5 %. However, considering the characteristics of flow resistance and improved heat transfer, MPCM-LFTF with a mass fraction of 10 % had the highest cooling efficiency and the efficiency factor was 57.0 % higher than that of the base fluid.
AtıfScopus35OpenAlex36İncele - MakaleYalnız künye2022Scopus SJRQ2Microstructure and corrosion investigation of FeCoCrNiMo0,5(MnAl)0,3 high entropy alloy produced by 316 L stainless steel scrap
Cihangir, Salih; Say, Yakup; Ozkul, İskender; Guler, Omer; Guler, Seval Hale
FeCrCoNiMo0,5(MnAl)0.3 high-entropy alloy (HEA) was manufactured via arc melting process by adding the related metal powders into scrap of 316 L stainless steel for corrosion resistance tests under salt and acid conditions. Cyclic potentiodynamic polarization experiments performed under acidic conditions revealed pre-passivation due to abundance of network modifying metals in HEA composition which was further analyzed by electrochemical impedance spectroscopy. Elemental resolved analysis of leftover solutions was used to compare metal ions released during corrosion. X-ray diffraction analysis indicated the phase change in heat treated HEA samples. Non-heat treated HEA samples can be compared with stainless steel under moderate corrosion conditions and had better hardness results.
AtıfScopus20WoS17OpenAlex19İncele - MakaleAçık Erişim2022Scopus SJRQ1Newly synthesized NiCoFeCrW High-Entropy Alloys (HEAs): Multiple impacts of B4C additive on structural, mechanical, and nuclear shielding properties
Gul, Ali Oktay; Kavaz, Esra; Basgoz, Oykum; Guler, Omer; ALMisned, Ghada; Bahceci, Ersin; Albayrak, M. Gokhan; Tekin, H.O.
High-Entropy Alloys (HEAs) are regarded as potential structural materials for fusion and next-generation fission reactors, which will be required to fulfil growing nuclear energy demands. In this study, a HEA-composite was synthesized by adding B4C to an HEA containing Ni. The microstructure of the obtained HEA-composite was examined and the changes in its mechanical properties were revealed. Additionally, the nuclear radiation shielding properties of the Ni-containing HEA, and the HEA-composite are investigated using experimental and theoretical methods. Our initial findings showed that with the addition of 2.5% B4C to the alloy, the hardness increased more than two times. The addition of B4C to the HEA matrix resulted in a more than 90% and a nearly twofold increase in compressive strength. The shielding qualities of gamma-ray and neutron radiation were investigated using experimental and theoretical approaches. Our findings demonstrated that increasing the B4C reinforcement considerably enhanced the composite material's neutron attenuation capabilities. On the other hand, no significant change in the gamma-ray shielding characteristics of HEA and HEA-composite samples was observed. The gamma-ray shielding characteristics of HEA and HEA-composite samples were compared to those of other alloy shields and commercial products. Our findings indicate that both HEA and HEA-composite samples exhibit superior gamma-ray shielding characteristics when compared to the control samples. It can be concluded that increasing B4C reinforcement may be a multifunctional tool in terms of improving the mechanical properties as well as neutron attenuation properties for advanced applications in nuclear radiation facilities and next-generation fission reactors. Additionally, due to their promising material features and higher gamma-ray shielding capabilities compared to other kinds of alloys and commercial shields, HEAs may be beneficial materials.
AtıfScopus33OpenAlex31İncele - MakaleYalnız künye2022Scopus SJRQ1Numerical evaluation of convective heat transfer properties of two-dimensional rotating PCM melt in the unilaterally heated rectangular container
Liu, Dinghai; Xie, Kai; Zhang, Hui; Qiang, Yujie; Yang, Di; Wang, Zhaoxiao; Zhu, Lidong; Akkurt, Nevzat; Du, Yanping; Shen, Meng
This paper carried out numerical investigations on the flow and heat transfer characteristics of a phase change with two-dimensional rotation of the three-dimensional paraffin (RT -27)-filled rectangular encapsulated container (PCM-REC) in space. A three-dimensional transient numerical heat transfer model was established and the enthalpy method was used to simulate the solid-liquid phase transition process and the flow evolution at the PCM interface. In this paper, the solid-liquid interface distribution, temperature distribution and melting time of PCM in PCM-REC heated at a constant temperature on one side were compared when rotated at different angles (0°, arctan (0.4), 2arctan (0.4) and 90°) along the heating direction and vertical heating direction. Results demonstrated that the peak value of maximum natural convection velocity increased from 0.0072 m/s to 0.0184 m/s with increasing radial height when PCM-REC was rotated in vertical heating direction. When PCM-REC was rotated in two dimensions by the same angle, the melting time was fastest when γ was an obtuse angle, and with the increase of the obtuse angle, the melting time shortened from 17 min to 6 min; when γ was an acute angle, the melting time was slowest, and with the decrease of the acute angle, the melting time lengthened from 49 min to 288 min.
AtıfScopus35OpenAlex40İncele - MakaleYayıncıda açık erişim2022Scopus SJRQ2A biomechanical study: Comparison of three different implant options in high Tibial osteotomy
Key, Sefa; Demir, Sukru; Aydın, Oğuz; Say, Yakup; Erten, Mehmet
Background: Many implant options could be preferable for fixation after osteotomy in varus knee medial compartment arthrosis. Due to usage characteristics, it is important to compare the biomechanical properties of them. For this purpose, we aimed to examine three different implant types biomechanically in our study. Methods: Ovine tibiae undergoing medial open-wedge high tibial osteotomy were fixed in vitro with three different implants using an angular wedge plate, a metal block plate and an external fixator system. The fixed ovine tibiae were subjected to axial tensile, axial loading and three-point bending tests in a test machine. All biomechanical tests were repeated five times, the maximum and minimum values were ignored, and the average values of the remaining three test results were taken into account. The test results were interpreted after converted into force-elongation curves in Trapezium-X software. Findings: Biomechanical test results revealed some differences between implant types. While the metal block plate had the highest axial tensile strength value, it was the fixation group showing the lowest strength in axial load tests. The used fixator system was the highest strength in axial load tests and the lowest strength in axial tensile tests. Interpretation: Considering the clinically significant forces related to the biomechanical stability of the three different implants used for high tibial osteotomy, the fixator system would appear to be slightly superior, although it should be noted that torsional forces, as well as parameters that could change in living tissue, might affect the results.
- MakaleAçık Erişim2022Scopus SJRQ2Synergistic effect of boron nitride and graphene nanosheets on behavioural attitudes of polyester matrix: Synthesis, experimental and Monte Carlo simulation studies
Başgöz, Öyküm; Güler, Seval Hale; Güler, Ömer; Canbay, Canan A.; Zakaly, Hesham M.H.; Issa, Shams A.M.; ALMisned, Ghada; Tekin, H.O.
We report the synergistic effects of boron nitride and graphene nanosheets on physical, structural, and nuclear radiation attenuation properties of polyester matrix-incorporated nanocomposites. Some critical material properties are thoroughly evaluated for several types of synthesized samples. Polyester is employed to strengthen graphene and boron nitride nanolayers, and their characteristics are investigated in detail. Additionally, we report the gamma-ray and fast neutron attenuation characteristics of synthesized nanocomposites to get a better understanding of the reinforcing effect as a function of material type and weight percentage. Thermal analysis findings indicate that adding graphene lowers the decomposition temperature but co-adding graphene and BNNS enhances thermal decomposition in comparison to graphene itself. Tensile tests showed that the inclusion of both GRP and GRP/BNNS strengthens the material. Among the polyester composite samples analyzed, the G3 sample with the most GNP reinforcement had the lowest HVL values throughout the broadest range of energy levels investigated. The recent findings may be beneficial to the scientific community in terms of incorporating these reinforcing types and ratios into polyester materials for a variety of applications, including industrial and research purposes.
AtıfScopus22OpenAlex19İncele - MakaleAçık Erişim2022Scopus SJRQ1Synthesis and structural, electrical, optical, and gamma-ray attenuation properties of ZnO-multi-walled carbon nanotubes (MWCNT) composite separately incorporated with CdO, TiO2, and Fe2O3
Basgoz, Oykum; Guler, Omer; Evin, Ertan; Yavuz, Cagdas; ALMisned, Ghada; Issa, Shams A.M.; Zakaly, Hesham M.H.; Tekin, H.O.
In this study, Fe2O3, TiO2, and CdO semiconductor metal oxides were separately incorporated into the ZnO-MWCNT composite at different weight percentages. Accordingly, several experimental analyses on electrical, optical, and radiation shielding characteristics of coupled semiconductor metal oxides nanocomposites were performed to determine their monotonic impact on the investigated material properties. Moreover, gamma-ray shielding properties of these novel materials were determined using MCNPX general-purpose Monte Carlo code. At 5% oxide addition, the maximum electrical conductivity was found in all groups for all temperatures. Moreover, 5% oxide reinforcement resulted in the maximum reflection characteristics in all groups. Among the CdO doped materials, the CZnOCd5 sample exhibits the highest electrical conductivity behaviour at room and high temperatures. The Eg value calculated for the CZnOCd5 sample was 3.284 eV. The CZnOCd2.5 and CZnOCd5 samples had the greatest Eg values when compared to the pure sample and the samples from other groups. The CZnOCd5 sample has the highest reflectance value in the CZnOCd group's reflectance graph. On the other hand, the maximum gamma-ray attenuation properties were reported for CZnOCd5 sample. Among the analysed samples, the CZnOCd5 sample's characteristics provide a preliminary motivation for a more comprehensive analysis of this material and assessment of potential radiation protection applications.
AtıfScopus29OpenAlex28İncele - Derleme MakaleYalnız künye2022Scopus SJRQ1Floating solar stills and floating solar-driven membranes: Recent advances and overview of designs, performance and modern combinations
Rashid, Farhan Lafta; Al-Obaidi, Mudhar A.; Hussein, Ahmed Kadhim; Akkurt, Nevzat; Ali, Bagh; Younis, Obai
For life to exist on earth, there must be water. Freshwater resources are in short supply due to industrialization and the world's rapid population expansion. Growing water shortage argues that using passive solar stills is the best and most practical solution in the world's arid and semi-arid regions. For applications in distant or rural coastal areas, floating solar stills are an appropriate technique. To provide accessibility to a wider population, the gadget should be constructed using inexpensive materials that are easily accessible nearby. However, the low-cost materials typically do not have the optimum physical characteristics, which reduces the overall performance of solar stills. This study intends to deliver a comprehensive review that summarizes recent research developments and gives a rundown of experimental, numerical, and experimental and numerical studies on floating solar stills and floating solar-driven membranes. This article also looks at a few more setups, researched parameters, and result-finding issues. Research on floating solar is currently ongoing, and recommendations for further research projects have been made in light of the study's findings.
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