Munzur ÜniversitesiMunzur ÜniversitesiAçık Erişim Arşivi · RDL Open

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  • MakaleYalnız künye2024Scopus SJRQ2
    Evaluation of effect of boric acid on thermoplastic starch: Morphological, mechanical, barrier, and optical properties

    Yoğurtçu, Hakan; Gürler, Nedim

    In this study, starch was modified with different amounts of boric acid, and the degree of substitution of the synthesized compounds at different temperatures and times was determined by Fourier transform infrared (FTIR) and titration methods. The degrees of substitution in both methods showed similar tendency. Optimum conditions were determined, and thermoplastic starch (TPS) and boric acid (B) films were prepared by casting method using glycerol as plasticizer. The morphological properties of the films were studied by scanning electron microscope-energy dispersive spectrometry (SEM-EDS). According to the FTIR results, it was observed that the B-O and B-O-C stretching vibrations increased when the amount of boric acid increased. The tensile strength, water barrier (swelling capacity, solubility, and water vapor permeability), and optical properties of samples were investigated. The swelling capacity, solubility, and water vapor permeability of the films decreased with the addition of 0.5% boric acid to the starch, but the highest tensile strength was achieved. The tensile strength for TPSB0.5% increased compared to control group TPS. In addition, the film showed the highest transparency. Thermoplastic film containing 0.5% boric acid can be used as a packaging material due to its improved mechanical and water barrier. Highlights: The thermoplastic starch and boric acid composite were successfully produced. The presence of boric acid was confirmed by energy dispersive spectrometry (EDS). The degree of substitution was determined by two different methods. Transparency increased with the addition of boric acid. Tensile strength improved with boric acid content.

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  • MakaleAçık Erişim2024Scopus SJRQ2
    Hysteresis gap-shrinking and structural effects of minor Al and Ti modifications on binary CuAl-based high-temperature shape memory alloys

    Karaduman, Oktay; Özkul, İskender; Aksu Canbay, Canan

    Cu-based shape memory alloys (SMAs), except for exhibiting shape recovery, superelasticity, and high damping, are desirable because these smart materials have higher electrical and thermal conductivity and much lower prices than NiTi SMAs. However, they also have some downsides in mechanical strength and brittleness (mostly stemming from their coarse grain structure) and thermal instability. Therefore, adding some grain refining elements to these SMAs to improve their shape memory effect (SME), and thermal, structural, and mechanical properties is a widespread and simple way that significantly affects their martensitic phase transitions, structure, and mechanical properties. One of these grain-refining elements is titanium. Its thermal conductivity is lower than those of Cu and Al elements and has a low solubility in Cu-matrix. Besides the effects of small Al variations, the use of minor amounts of titanium in binary CuAl-base alloys can show impressive effects on all characteristics of these shape memory alloys, such as shape memory effect properties, martensitic transformation kinetics parameters, and microstructural features. In this research work, CuAlTi ternary high-temperature shape memory alloys (HTSMAs) with new compositions were produced by the arc melting method without a complicating use of Mn or Ni components in usual ternary CuAlMn and CuAlNi shape memory alloys. Thermal analyses of the prepared samples of the alloys were investigated by using differential scanning calorimetry (DSC) and differential thermal analysis (DTA) measurements. In contrast, x-ray diffraction (XRD) test results and optical micrographs were used for analyzing the structure of the alloy samples. The effect of different amounts of low soluble and grain refining Ti element on the binary CuAl alloy system was investigated.

    AtıfScopus2WoS2OpenAlex2
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  • MakaleYalnız künye2024Scopus SJRQ2
    A fuzzy Bayesian network risk assessment model for analyzing the causes of slow-down processes in two-stroke ship main engines

    Başhan, Veysi; Yucesan, Melih; Gul, Muhammet; Demirel, Hakan

    This paper presents a risk assessment approach for analyzing the causes of malfunction-related main engine slowdowns. A fuzzy Bayesian Network-based methodology is used to assess the factors contributing to the engine’s slow-down processes. The model addresses the complexity and uncertainty inherent in maritime operations with fuzzy sets where numerous interrelated factors can affect engine performance, and the Bayesian network to capture probabilistic dependencies. It considers various potential causes of the slow-down of ship engines that the manufacturer provides. Results demonstrate the model's ability to identify the influential factors leading to engine slow-down events and quantify the overall risk. Integrating fuzzy logic and Bayesian Networks comprehensively assesses relevant risk factors. It enables maritime stakeholders to manage engine performance and improves operational safety proactively. Findings can inform decision-makers, enabling the implementation of targeted maintenance strategies, fuel quality control measures, and crew training programs in the maritime industry.

    • SDG 9 · Sanayi, Yenilikçilik ve Altyapı
    AtıfScopus19WoS17OpenAlex18
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  • MakaleYalnız künye2024Scopus SJRQ3
    Simultaneous features of ternary hybrid nanoparticles on thermal radiative flow configured by Darcy–Forchheimer porous surface

    Nasir, Saleem; Sirisubtawee, Sekson; Akkurt, Nevzat; Ali, Ishtiaq; Gul, Taza; Juntharee, Pongpol

    Due to its remarkable thermodynamic development in various engineering sciences, the dispersion of nanostructures in classical base liquids is receiving greater attention from researchers and scientists. In light of the aforementioned inspirations, the suggested research is associated with using a water-based ternary-hybrid nanofluid that contains three unique nanostructures, silicon dioxide, titanium dioxide and aluminum oxide to optimize the heating process in science and engineering. In this situation, the influence of a chemically reactive magneto-hydrodynamics (MHD) Darcy–Forchheimer ternary hybrid composites transport involving nonlinear radiation across an exponentially permeable stretched surface is highlighted with the model's physical initial and boundary constraints. The simulation of the heat expression also includes the impacts of nonlinear thermal radiations, energy supply, energy dissipation and magnetic force. Furthermore, the interpretation of Buongiorno's theory involves spontaneous and thermophoresis diffusions. Entropy analysis is explained using the second law of thermodynamics. We converted the model framework for fluid movement, energy and mass transfer (together with ternary hybrid nanofluid characteristics) into self-similar nondimensional differential equations, that were then further analytically evaluated by using the homotopy asymptotic method (HAM) technique via Mathematica software. The acquired results are illustrated numerically and graphically to study the behavior of fluid flow, heat, concentration distribution, drag force, rate of heat and mass transfer for various emergent components to gain scientific comprehension. With the growing values of magnetic, porosity and Forchheimer number, the nature of the velocity profile goes down.

    AtıfScopus10OpenAlex11
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  • MakaleYalnız künye2024Scopus SJRQ1
    Synthesis, characterization and application of cross-linked functional terpolymer through epoxy group as sorbent for extraction of cadmium from waters and foods: Multivariate optimization

    Yılmaz, Ersen; Boztuğ, Ali; Ul Haq, Hameed; Boczkaj, Grzegorz; Altunay, Nail

    The purpose of this study was to develop a selective sorbent for cadmium ions (Cd(II)) enrichment in orbital shaker assisted solid phase microextraction (OS-SPME) from different aqueous and food samples. A maleic anhydride-styrene-glycidyl methacrylate (MA-St-GMA) terpolymer was synthesized and characterized in detail. Experimental variables of sample preparation step were optimized using a central composite design (CCD). The final determination step was performed using flame atomic absorption spectroscopy (FAAS). The MA-St-GMA sorbent exhibited a high adsorption capacity (195.9 mg g−1) for the Cd(II) ion. The developed method under optimal conditions provides satisfactory performance and a significant improvement compared to other protocols available in the literature. The linear range and detection limit of the method is 0.1–130 ng mL−1 and 0.03 ng mL−1, respectively. The robustness, intraday/interday precision, selectivity, and accuracy of the method were investigated. To further validate the method, a dedicated series of analysis was performed using certified reference materials (CRMs). This part of the study confirmed the applicability of the method for routine analysis. The OS-SPME-FAAS method was validated using water and food samples. Relative standard deviations and recovery for real-world samples were in ranges 1.7–2.2 % and 95.5–98.5 %, respectively. As a result, the MA-St-GMA sorbent showed that it could quantitatively extract Cd(II) ions from aqueous solution.

    • SDG 6 · Temiz Su ve Sanitasyon
    AtıfScopus9WoS8OpenAlex9
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  • MakaleYalnız künye2024Scopus SJRQ3
    Assessing the Chemical Composition, Antioxidant and enzyme Inhibitory Effects of Pentapleura subulifera and Cyclotrichium glabrescens Extracts

    Nilofar, Nilofar; Zengin, Gokhan; Acar, Mikail; Bouyayha, Abdelhakim; Youssra, Aalilou; Eldahshan, Omayma; Fayez, Shaimaa; Fahmy, Nouran

    The Lamiaceae family, encompassing diverse plant species, holds significant value in food, medicine, and cosmetics. Within this family, Pentapleura subulifera and Cyclotrichium glabrescens, relatively unexplored species, were investigated for their chemical composition, antioxidant capacity, and enzyme-inhibiting effects. The chemical composition of hexane, methanolic, and aqueous extracts from P. subulifera and C. glabrescens were analyzed using LC-ESI-MS/MS and the non-polar hexane fraction was investigated via GC-MS. The antioxidant potential of the extracts was determined through radical scavenging, reducing power and metal chelating assays. Additionally, inhibitory activity against six enzymes – acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase, amylase, and glucosidase – was examined. The aqueous extract of P. subulifera and the methanolic extract of C. glabrescens exhibited elevated phenolic content at 129.47 mg gallic acid equivalent (GAE)/g and 55.97 mg GAE/g, respectively. Chemical profiling of the constituents of the two plant species resulted in the identification of a total of twenty compounds. The majority of which belonged to flavonoids and quinic acid derivatives, primarily concentrated in the methanol and aqueous extracts. Among all antioxidant assays, the aqueous extracts of P. subulifera demonstrated superior antioxidant activity, with the highest recorded activity of 404.93 mg trolox equivalent (TE)/g in the cupric reducing antioxidant capacity (CUPRAC) test. Meanwhile, the hexane extract of C. glabrescens exhibited the highest AChE inhibitory activity at 2.71 mg galanthamine equivalent (GALAE)/g, followed by the methanol extract of P. subulifera at 2.41 mg GALAE/g. These findings unequivocally establish the notable antioxidant and enzyme inhibitory activity of P. subulifera and C. glabrescens extracts, underscoring their potential as a source of valuable natural antioxidants.

    AtıfScopus15OpenAlex14
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  • MakaleAçık Erişim2024Scopus SJRQ4
    Oxidative and physiological effects of carvedilol, a beta–blocker, in Daphnia magna; [Efectos oxidativos fisiológicos del carvedilol, un betabloqueante, en Daphnia magna]

    Seker, Engin

    Carvedilol is a beta–blocker. Beta–blockers affect the heart and circulation. carvedilol is used to treat heart failure and hypertension. Although this substance has effects in humans and some animals, its effect on the physiological and antioxidant status of daphnids is unknown. The aim of this study was to determine the effect of carvedilol doses (0, 0.125, 0.45 and 0.90 mg·L-1) on physiological activities (heart rate, postabdominal paw activity and thoracic limb movements) and oxidative stress. In Daphnia magna; malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), total glutathione (GSH) and glutathione S transferase (GST) markers were examined. The activity of physiological parameters in D. magna exposed to all carvedilol concentrations was found to be lower than in the control group, and the differences were statistically significant (P<0.01). Application of carvedilol to D. magna resulted in lower GSH content in all groups throughout the experimental period. MDA, SOD, CAT and GST activity were improved. These findings indicate that carvedilol causes physiological and biochemical changes in D. magna. Daphnia species have great potential to provide valuable insights into the mechanisms of human medicine. More comprehensive research is needed on this subject.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    ScopusWeb of Scienceİncele
  • MakaleAçık Erişim2024Scopus SJRQ2
    RECONSTRUCTION OF POTENTIAL OF DISCONTINUOUS STURM — LIOUVILLE OPERATOR FROM SPECTRAL DATA

    Akcay, O.

    We deal with the inverse spectral problem of the discontinuous Sturm — Liouville operator. The aim is we to determine the potential q(x) and the boundary constant ℎ by a given spectral data. We provide the algorithm for reconstructing the potential q(x) from the spectral data.

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  • MakaleYalnız künye2024Scopus SJRQ2
    Insight into novel inhibitors from Sterculia urens against Cholera via pharmacoinformatics and molecular dynamics simulation approaches

    Rahman, M. Oliur; Ahmed, Sheikh Sunzid; Alqahtani, Ali S.; Cakilcioğlu, Uğur; Akbar, Mohammad Ahsanul

    The underdeveloped countries with large populations are facing a grave global threat in the form of cholera. Vibrio cholerae, the etiologic agent of Cholera has drawn attention recently due to antimicrobial resistance and resulting outbreaks that necessitates establishment of novel medications to counteract virulence and viability of the pathogen. Sterculia urens Roxb. (Malvaceae) is an ethnomedicinally important tree, which harbors a good number of bioactive phytocompounds. In the present study, 53 phytocompounds of S. urens were screened against the promising target ToxT of V. cholerae employing structure-based drug design approach that revealed three lead compounds, viz., 4,4,5,8-Tetramethylchroman-2-ol (−8.2 kcal/mol), Beta-Bisabolol (−8.2 kcal/mol) and Ledol (−8.7 kcal/mol) with satisfactory ADMET properties. Molecular dynamics simulation for 150 ns unveiled notable compactness and structural stability for the lead compounds considering RMSD, RMSF, Rg, MolSA, PSA and protein-ligand contacts parameters. Molecular mechanics-based MM/GBSA binding energy calculation revealed Beta-Bisabolol (−66.74 kcal/mol) to have better scores than 4,4,5,8-Tetramethylchroman-2-ol (−47.42 kcal/mol) and Ledol (−65.79 kcal/mol). Enzymes were mostly found as drug target class, and Nabilone was found as a structurally similar analog for 4,4,5,8-Tetramethylchroman-2-ol. These discoveries could aid in revealing new antibacterial medications targeting ToxT to combat Cholera. Communicated by Ramaswamy H. Sarma.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    AtıfScopus8OpenAlex8
    ScopusWeb of SciencePubMedİncele
  • MakaleYalnız künye2024Scopus SJRQ2
    Effects of mutation in myostatin exon 3 on growth and carcass characteristics of Savak Akkaraman sheep

    Kar, Bulent; Bahar, O.Z.; Yazdic, Ferit Can; Karaman, Altug

    The myostatin gene (MSTN) is one of the main regulatory genes involved in muscle growth and development in many animals. This study aims to determine the variations in the exon 3 region associated with MSTN expression in Savak Akkaraman sheep and analyze their relationship with growth characteristics. Molecular analyses (RLFP, Real-Time PCR and DNA sequencing) were performed using DNA and RNA isolations from 70 different sheep blood and meat samples. As a result of the study, exon 3 region analysis was performed using NgomIV, AluI, DraI, HaeIII and MspI restriction endonucleases to determine the genetic diversity in Savak Akkaraman sheep breed. Two genotypes (MM and Mm) were detected for MSTN/MspI and a monomorphic mm genotype indicating the conserved exon 3 region for MSTN/HaeIII. Additionally, four new Single Nucleotide Polymorphisms (SNPs) were detected at different positions (164th, 204th, 347th, and 441th) in the working exon region. Two of these SNPs (204th T→G: isoleucine→ methionine and 347th C→A-G: proline→glutamine-arginine) caused amino acid changes. In expression studies, it was determined that MSTN gene expression was higher in female sheep than in male sheep (p<0.05). The MM genotype (MSTN/MspI) was significantly associated with increased weight gain and MSTN expression, while TT genotype at SNP 204 and GG genotype at SNP 347 was found to be associated with meat yield and growth traits (p<0.05). As a result, the genetic differences and functional effects of the new genotypes determined in this study may shed light on breeding strategies aiming to increase meat production.

    • SDG 2 · Açlığa Son
    AtıfScopus3WoS3OpenAlex4
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  • MakaleAçık Erişim2024Scopus SJRQ2
    Seismic Resistance and Performance Evaluation of Masonry Dwellings After the February 6, 2023, Kahramanmaraş Earthquake Sequence in Türkiye

    Onat, Onur; Yön, Burak; Uslu, Ali; Öncü, Mehmet Emin; Varolgüneş, Sadlk; Karaşin, I.B.; Gör, Mesut

    On February 6, 2023, two catastrophic earthquakes occurred on the East Anatolian Fault. The earthquakes had magnitudes of Mw = 7.7 and 7.6 and struck Kahramanmaraş-Pazarclk and Kahramanmaraş-Elbistan, respectively. The Kahramanmaraş-Pazarclk earthquake was triggered at 04:17 local time on the Dead Sea Fault (a branch of the East Anatolian Fault). The last earthquake on the addressed fault occurred about 500 years ago. The recorded peak ground acceleration (PGA) at the Pazarclk station reached 2.05g. In addition, the Pazarclk earthquake triggered two independent earthquakes, the Nurdaǧl and Islahiye earthquakes, which occurred 10 min later than the Pazarclk earthquake. However, the last earthquake, with its epicenter in Kahramanmaraş-Elbistan, struck at 13:24 local time. The recorded PGA for the Elbistan earthquake is 0.68g. This study aims to present the fault rupture mechanism of the February 6, 2023, Kahramanmaraş earthquakes, earthquake characteristics, and to evaluate the performance of masonry dwellings during the Kahramanmaraş earthquake doublet, which affected 10 provinces and numerous towns and villages. This paper also aims to illustrate the damage and failure mechanisms of the masonry dwellings, despite unexpectedly high accelerations that exceeded the design spectrum in the field, specifically in Kahramanmaraş, Gaziantep, Hatay, and Malatya, according to the current earthquake code in use.

    • SDG 11 · Sürdürülebilir Şehirler ve Topluluklar
    AtıfScopus16OpenAlex22
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  • MakaleAçık Erişim2024Scopus SJRQ2
    Titanium alloys: A closer-look at mechanical, gamma-ray, neutron, and transmission properties of different grade alloys through MCNPcode application

    ALMisned, Ghada; Guler, Omer; Sen Baykal, Duygu; Kilic, G.; Tekin, H.O.

    Titanium alloys play a vital role in optimizing the effectiveness and security of nuclear reactors, strengthening structural durability, and facilitating the effective handling of nuclear waste. The aim of this study is to investigate the gamma-ray, neutron, and transmission properties of four common titanium alloys through the examination of the deposited energy amount in the liquid sodium coolant material, in relation to the mechanical properties of these alloys. MCNP (version 6.3) is utilized for designing the titanium pipes. Next, the pipes were re-designed considering the elemental mass fractions and densities of the investigated titanium alloys. Grade 26 sample is reported with the highest values of mass attenuation coefficients and the lowest HVL values among those investigated alloys. Grade 26 is reported to have the lowest TF value, whereas Grade 12 demonstrated the highest TF value. The highest Effective Removal Cross Section (ΣR, 1/cm) value against fast neutrons is reported for Grade 26. The utilization of Grade 26 sample as pipe material resulted in the lowest deposited energy amount (MeV/g) and subsequent lowest contamination in the coolant material. Out of the alloys that were chosen for analysis, it has been determined that Grade 26 exhibits the highest level of strength. It can be concluded that the Grade 26 alloy exhibits desirable characteristics for applications in nuclear technologies that require superior gamma-ray and neutron absorption properties, as well as exceptional mechanical properties. Nevertheless, it is essential to emphasize the importance for ongoing studies to enhance the existing material properties of Grade 26, with the aim of achieving improved safety and efficacy in nuclear applications.

    AtıfScopus11OpenAlex11
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  • MakaleYalnız künye2024Scopus SJRQ1
    Assessment of short and long-term pozzolanic activity of natural pozzolans using machine learning approaches

    Khatti, Jitendra; Polat, Berivan Yılmazer

    This investigation introduces the optimal performance models for predicting the compressive strength (CS) and pozzolanic activity index (PAI) by comparing the machine learning models. The machine learning models, i.e., multilinear regression (MLR), support vector machine (SVM), gaussian process regression (GPR), decision tree (DT), random forest (RF), and gene expression programming (GEP) have been trained (TRN) and tested (TST) by 28 and 7 data points. For the first time, the SiO2, Al2O3, Fe2O3, SiO2 +Al2O3 +Fe2O3, reactive SiO2, Blaine specific surface area, and specific gravity have been used as input variables to compute the CS, and 28 days PAI (28PAI), and 90 days PAI (90PAI) of the natural pozzolans. The multicollinearity analysis showed the SiO2, Al2O3, Fe2O3, SiO2 +Al2O3 +Fe2O3, reactive SiO2, and specific gravity have problematic multicollinearity (variance inflation factor – VIF > 10). Therefore, the root mean square error (RMSE), mean absolute error (MAE), correlation coefficient (R), performance index (PI), and variance accounted for (VAF) metrics have been implemented to evaluate the model's performance and multicollinearity impact. From the comparison of models, it has been recorded that model GPR outperformed the MLR, SVM, DT, RF, and GEP models in predicting CS (PI = 1.29, VAF = 71.31, R = 0.8473, MAE = 0.9390 MPa), 28PAI (PI = 1.87, VAF = 94.88, R = 0.9744, MAE = 0.7295 %), and 90PAI (PI = 1.72, VAF = 88.11, R = 0.9393, MAE = 1.2444 %) in the TST phase, close to ideal values. The score, generalizability. Wilcoxon test, uncertainty analysis, Anderson-daring test, and accuracy metrics have confirmed the superiority of GPR models in predicting CS, 28PAI, and 90PAI of natural pozzolans.

    • SDG 9 · Sanayi, Yenilikçilik ve Altyapı
    AtıfScopus28WoS25OpenAlex28
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  • MakaleYalnız künye2024Scopus SJRQ2
    On β-titanium alloys: tailoring gamma-ray, and neutron transmission properties for nuclear and biomedical applications

    Almisned, Ghada; Baykal, Duygu Sen; Alkarrani, Hessa; Güler, Ömer; Kilic, Gokhan; Mesbahi, Asghar; Tekin, Huseyin Ozan

    This study explores the gamma-ray and neutron transmission properties of β-Titanium alloys pivotal for their performance in nuclear and biomedical applications. Utilizing the Monte Carlo N-Particle (MCNP 6.3) simulations, we analyzed a spectrum of Ti-based alloys modified with elements like molybdenum (Mo), zirconium (Zr), niobium (Nb), and hafnium (Hf) to determine their radiation attenuation properties. Key parameters such as mass and linear attenuation coefficients, half-value layers, exposure buildup factors, and fast neutron effective removal cross-section values were computed, revealing significant enhancements in attenuation with the addition of high-Z elements. Specifically, alloys like Ti50Hf50 and (TiZr)40Cu60 exhibited superior photon and fast neutron attenuation due to their high-Z constituents. For instance, Ti50Hf50 showed a mass attenuation coefficient of 0.217 cm2/g and a half-value layer of 2.97-cm at 0.1 MeV photon energy, while (TiZr)40Cu60 demonstrated similar performance with a mass attenuation coefficient of 0.198 cm2/g and a half-value layer of 3.26-cm. These alloys also exhibited effective neutron removal cross-section values of 0.115 cm-1 and 0.130 cm-1, respectively. Alloys with lower-Z elements showed less attenuation, which may be beneficial in scenarios requiring reduced radiographic contrast in biomedical applications. The MCNP outcomes were in strong agreement with standard data, affirming the accuracy of computational methods in predicting material behavior. In conclusion, tailored alloy development is crucial for improving radiation shielding and diagnostic visualization, with broader implications for patient safety and treatment efficacy.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    AtıfScopus3OpenAlex3
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  • MakaleYalnız künye2024Scopus SJRQ2
    Recycling Ti1.0Nb0.3Ta0.07Zr0.05 Conventional Alloys: Production of Non-equimolar TiZrCrNb0.3Ta0.07 Medium Entropy Alloys with the Addition of Cr for Improved In Vitro Corrosion Resistance

    Guler, Omer; Say, Yakup; Dikici, Burak; Ozkul, Iskender; Niinomi, Mitsuo

    A non-equimolar TiZrCrNb0.3Ta0.07 medium entropy alloy (MEA) was successfully designed as theoretical and produced by arc-melting method from Ti1.0Nb0.3Ta0.07Zr0.05 (TNTZ) scraps for possible usage in biomedical applications in this study. The main aim of this study is to find an alternative way to recycle with a reduced carbon footprint the available TNTZ conventional alloy and convert it to a value-added product during this recycling such as medium entropy alloys (MEAs) via using less energy. To examine the microstructural changes induced by the annealing process, scanning electron microscopy was employed. The chemical composition of the HEAs was assessed using energy-dispersive spectroscopy and x-ray photoelectron spectroscopy. Additionally, x-ray diffraction analysis was used to determine the crystallographic structure and phase composition of HEAs. Furthermore, in order to evaluate the electrochemical corrosion performance of the alloys, comprehensive in vitro corrosion tests were conducted in a simulated body fluid solution, specifically Hanks's Balanced Salt Solution. Some elemental segregation has been observed after the annealing process. A big migration of Zr and Cr elements was observed in the samples from the interdendritic region to the dendritic area during the annealing process. This segregation resulted in approximately 1.4 times increase in the hardness of the MEA. The electrochemical corrosion results showed that the in vitro resistance of the MEAs was higher than that of its conventional scraps.

    • SDG 12 · Sorumlu Üretim ve Tüketim
    AtıfScopus5OpenAlex5
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  • MakaleYalnız künye2024Scopus SJRQ3
    Powder coating waste filler in high-density polyethylene – Variations in morphology, mechanical and thermal performance; [Variationen in Morphologie, mechanischer und thermischer Leistung von Pulverlackrecyclaten als Füllstoff in Polyethylen mit hoher Dichte]

    Kısmet, Y.

    In the present study, electrostatic powder coating waste was recycled and employed to reinforce high-density polyethylene. The hydrolysis method was preferred to modify the powder coating waste of various systems, and they were mixed with high-density polyethylene at various weight ratios. The mixtures were prepared in a mechanical mixer and then in an extruder to obtain a homogeneous mixture. This homogeneous structure was pressed into molds with a plastic injection device to obtain standard tensile samples. Mechanical and thermal tests were conducted on the samples. It was determined that the tensile stress of the sample decreased with the increase in filler content. The changes in sample tensile strength were investigated after the samples were aged. Three-point bending strength of the samples was also investigated and it was observed that they became more resistant to vertical loads as the filler content increased. The Izod impact strength of the samples differed based on the filler type and weight ratio. Furthermore, mass loss in the produced mixtures was determined with thermogravimetric analysis. The matrix and filler bonding mechanisms were observed under an electron microscope.

    • SDG 9 · Sanayi, Yenilikçilik ve Altyapı
    • SDG 12 · Sorumlu Üretim ve Tüketim
    AtıfScopus1WoS1OpenAlex1
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  • MakaleYalnız künye2024Scopus SJRQ1
    Radiation shielding properties of composites of TiZrNbHfTa refractory high entropy alloy reinforced with TiZrNbHfTaOx high-entropy oxide

    Güler, Ömer; Yılmaz, Demet; Kanca, M. Sait; Edalati, Kaveh; Taşgın, Yahya

    Radiation shielding materials play a critical role in advancing the next generation of nuclear reactors. Among these, high-entropy materials with refractory properties emerge as a new category for radiation shielding applications. This study introduces TiZrNbHfTa-TiZrNbHfTaOx composites tailored for such purposes. Initially, a TiZrNbHfTa refractory high-entropy alloy (RHEA) is synthesized via mechanical alloying, followed by the oxidation of the alloy to obtain its refractory high-entropy oxide (RHEO), TiZrNbHfTaOx. Composites are then prepared by blending 5%, 10%, and 20% weight fractions of RHEO with RHEA using mechanical alloying. Comparative analysis of shielding properties reveals a decrease in mass attenuation coefficient and effective atomic number with increasing RHEO content. While RHEA exhibits superior shielding performance against gamma photons and neutrons, the composite containing 20% RHEO emerges as the optimal shield against alpha and proton irradiations. The equivalent neutron dose rate and removal cross-section values are obtained 49.8% and 0.142 for the composite with 20% RHEO, respectively. These findings, supported by computational simulations in this study, contribute valuable insights for the advancement of novel shielding materials crucial for future nuclear reactor technologies.

    AtıfScopus24WoS22OpenAlex24
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  • MakaleAçık Erişim2024Scopus SJRQ1
    Novel formulations ameliorate osteoarthritis in rats by inhibiting inflammation and oxidative stress

    Erten, Fusun; Ozdemir, Oguzhan; Tokmak, Muhammed; Durmus, Ali Said; Ozercan, Ibrahim Hanifi; Morde, Abhijeet; Padigaru, Muralidhara; Sahin, Kazim

    The study tested new oral plant-based formulations (F) on rats with monosodium iodoacetate (MIA)-induced osteoarthritis, measuring inflammation, antioxidant levels, paw size, stride, and analyzing knee joint images. Fifty-six female Sprague Dawley rats were allocated into 8 groups: (1) Control, (2) MIA (OA induced with MIA), (3) MIA + F1 [curcuminoids+gingerols+acetyl-11-keto-β boswellic acid (AKBA)], (4) MIA + F2 (curcuminoids+Withania glycosides+AKBA), (5) MIA + F3 (curcuminoids+total withanolides+AKBA), (6) MIA + F4 (curcuminoids, AKBA), (7) MIA + UCII (type II collagen), and (8) MIA + GCHON (Glucosamine Chondroitin). Treatments F1 to F4 reduced right joint diameter and improved stride length and paw area in OA rats. Despite improvements with treatments F1 to F4, there was no significant difference between these groups (p >.05). In OA animals, F1 to F4 treatments decreased MDA levels and increased antioxidant enzymes activities (p <.001). This was done by reducing levels of inflammatory markers and enzymes like IL-1β, IL-6, MMP-8, TNF-α, CRP, COMP, and LOX-5, while increasing the anti-inflammatory cytokine IL-10. In conclusion, these plant-based treatments significantly reduced osteoarthritis severity, slowed disease progression by reducing inflammation, and protected joints from damage, showing a protective effect in rats with induced osteoarthritis, likely due to their anti-inflammatory and antioxidant properties.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    AtıfScopus14WoS11OpenAlex10
    ScopusWeb of SciencePubMedİncele
  • MakaleYalnız künye2024Scopus SJRQ2
    A risk assessment model with dependent failure modes for the manufacturing and design processes of medical equipment

    Lo, Huai-Wei; Gul, Muhammet; Yucesan, Melih; Liaw, Ching-Fang

    The reliability of medical equipment is paramount for surgical success. Manufacturers are continuously exploring risk assessment and improvement strategies to prevent equipment malfunctions during surgery. Failure mode and effects analysis (FMEA) can primarily be divided into two types: DFMEA (Design FMEA) and PFMEA (Process FMEA). Traditional FMEA serves as a practical tool for identifying and prioritizing key failure modes (FMs). However, past FMEA research has overlooked the interdependencies among FMs, treating them as independent entities, which does not align with real-world operations. This paper introduces a groundbreaking risk dependency assessment model aimed at addressing the influential relationships among FMs. The modified technique for defining the influential relationship of failure modes (modified TEDIR-FMs) is developed to compute the relative risk scores of different FMs accurately. At its core, this paper integrates concepts from multiple criteria decision-making (MCDM) techniques into FMEA, with a particular focus on the interdependencies of failure modes in the manufacturing and design manufacturing processes of medical equipment. The model’s application is demonstrated through a case study on a medical device for hernia surgery. The introduction of modified TEDIR-FMs not only enhances the accuracy of risk assessments but also offers a fresh perspective on risk management within the design and manufacturing processes. The research results indicate that the three failure modes with the highest risk are “adhesive does not deploy or only partially deploys from the dispenser,” “the mesh does not adhere to the adhesive,” and “the adhesive drips from the tip.” In the manufacturing and design processes of this device, greater attention should be given to improving the adhesive components.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    AtıfScopus5WoS4OpenAlex2
    ScopusWeb of Scienceİncele
  • MakaleYalnız künye2024Scopus SJRQ1
    A comprehensive risk assessment framework for mooring risks at hydrocarbon berths using fuzzy rule-based Bayesian network and multi-attribute decision-making

    Demirel, Hakan; Başhan, Veysi; Yucesan, Melih; Gul, Muhammet

    Mooring operations -especially at hydrocarbon berths- are critical components of the marine and offshore industry. They usually involve securing the berths of ships carrying valuable cargo and ensuring the safety of personnel, assets, and the environment. For this purpose, a comprehensive risk assessment framework for mooring operations at hydrocarbon berths is proposed in this study. This framework helps evaluate risks using a rule-based Bayesian network. In the assessment of mooring risks, four risk parameters of severity, occurrence, detection, and maintenance are considered to construct the BN structure of each mooring risk. These parameters are weighted with the aid of the fuzzy Best Worst Method. Hereafter, a fuzzy rule-based system is constructed by incorporating BN to determine a risk priority score. The framework also develops mitigation strategies to maintain effective risk management for safe and secure maritime transportation. Sensitivity analyzes and comparison studies were conducted to test the validity of the proposed comprehensive risk management framework. The study reveals that the most critical risk is associated with Technical Failures (Q1) in the cluster pertaining to the automation of Quick Release Hooks. This risk stems from technical malfunctions in automation systems, encompassing sensors and control mechanisms, potentially resulting in the unintended release of mooring lines. The second highest priority risk is linked to Human Error (M1) in the mooring risks cluster, attributed to human errors such as inadequate training, miscommunication, and procedural mistakes during mooring operations, posing risks of accidents and damage to ships and infrastructure. Conversely, the least significant risk, Redundancy (Q5), focuses on redundancy. This risk is associated with automation and underscores the importance of implementing redundancy mechanisms to ensure the safe continuation of mooring operations in the face of system failures. In conclusion, the proposed comprehensive risk assessment framework offers a systematic approach to evaluate and prioritize mooring risks at hydrocarbon berths. The study’s findings emphasize the critical importance of addressing technical malfunctions in the automation of Quick Release Hooks and human errors during mooring operations. By identifying the most significant risks and developing mitigation strategies, this framework contributes to enhancing the safety and security of maritime transportation, particularly in the context of hydrocarbon berths.

    • SDG 9 · Sanayi, Yenilikçilik ve Altyapı
    AtıfScopus11WoS11OpenAlex13
    ScopusWeb of Scienceİncele