Sürdürülebilir Kalkınma Amaçları

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• MakaleAçık Erişim2026/r/munzur/6113
  Effect of Temperature on the Fracture Characteristics of Hot Mix Asphalt Mixtures Using the Semi-Circular Bend (SCB) Test

  Ince, Ragip; Furtana, Beyza; Yılmaz, Mehmet

  This study investigates the temperature-dependent fracture behavior of hot mix asphalt using the Semi-Circular Bend (SCB) test and nonlinear fracture mechanics principles. SCB specimens prepared from gyratory-compacted mixtures were notched at three depths and tested at four different temperatures (23 °C, 0 °C, -11 °C, and -22 °C). The Two-Parameter Model (TPM), the compliance approach, and the J-integral method were employed to determine nonlinear fracture parameters, including fracture toughness, effective crack length, elastic modulus, and critical crack tip opening displacement (CTODc). Load CMOD curves were analyzed to determine elastic modulus from initial compliance values, while nonlinear fracture toughness was calculated based on equivalent crack length at peak load. Results showed that temperature is the most dominant variable influencing fracture behavior, explaining more than 75% of the observed variation. As the temperature decreased, the elastic modulus and fracture toughness significantly increased, indicating stiff and brittle behavior, whereas higher temperatures led to increased CTODc and more ductile fracture characteristics. The findings demonstrate that nonlinear fracture mechanics and TPM provide reliable and physically meaningful fracture characterization for asphalt mixtures. The outcomes highlight the importance of temperature in pavement fracture performance and confirm that nonlinear fracture approaches are useful tools for performance-based asphalt pavement design, particularly in cold climate regions susceptible to thermal cracking.

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• MakaleAçık Erişim2025/r/munzur/6015
  Advances in Materials Innovations in Half Metallic Heusler Alloys for Structural Magnetic and Energy Spintronic Technologies

  Özkul, İskender; Kalay, Ece; Guler, Omer; Aksu Canbay, Canan

  Half-metallic Heusler alloys are promising materials for spintronic and thermoelectric applications. These alloys exhibit metallic conductivity in one spin direction while acting as insulators in the opposite spin direction, enabling nearly 100% spin polarization. This property is crucial for spintronic devices such as magnetic tunnel junctions (MTJs), magnetic random-access memories, and spin-based transistors. This study investigates the electronic, magnetic, and structural properties of Heusler alloys, focusing on their synthesis methods, atomic ordering, and modelling via density functional theory (DFT). DFT-based calculations serve as a key tool for predicting band structures, spin polarization, and magnetic properties. Additionally, the effects of disorder, strain, and compositional changes on material properties are analysed to explore performance optimization strategies. The potential applications of Heusler alloys in spintronic memory devices, thermoelectric energy conversion, and quantum technologies are also discussed. This work is presented as a review article and systematically compiles and interprets findings from the existing literature to provide a broad understanding of the topic. By integrating theoretical and experimental approaches, this study provides a comprehensive overview of the role of these materials in advanced technological applications.

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• MakaleAçık Erişim2024/r/munzur/6303
  Effect of Dietary Zinc on the Antioxidant Parameters of Juvenile Common Carp (Cyprinus carpio)

  Aksu, Önder; Harlıoğ, Muzaffer Mustafa; Mustafa, Shokri; Batool, Zahra

  Zinc (Zn) is an essential micro mineral needed for the proper growth and immune function of fish. This investigation was designed to examine the antioxidant role of a fortified diet with different Zn levels in the muscle and liver tissues of carp fry. A four-iso-nitrogen (35% crude protein) practical diet was produced that included graded levels of dietary zinc sulphate as a nutritional zinc resource in the fundamental diet supplemented with increased zinc levels (T1, control, 85 mg Zn kg-1, T2 105 mg Zn kg-1, T3, 125 mg Zn kg-1 and T4, 145 mg Zn kg-1). Even though the SOD and CAT analysis results did not show a linear increase in the increasing Zn ratio in the diets, higher values were obtained compared to the control groups. SOD highest values in T3 for the liver (0.713 ± 0.220 U/ml) and T1 for muscle (0.751 ± 0.144 U/ml), CAT values were highest in T2 for the liver (0.849 ± 0.115 nmol/dk/m) and T2 for muscle (1.059 ± 0.148 nmol/dk/m) was obtained. MDA values were completely higher for the muscle than for the control group, and for the liver, a lower value was obtained in the T2 trial group than in the control group (1.671 ± 0.230 µM). The results of the study showed that Zn contributed significantly to the nutrition of carp fish. It can be concluded that the findings of SOD and CAT analysis endorse the positive contributions of using 105 mg Zn in the diets to promote the antioxidant defense of juvenile carp fish.

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• MakaleAçık Erişim2024/r/munzur/6302
  Blum Blum Shub Tabanlı Yeni Bir Kriptografik Anahtar Planlama Algoritması

  Artuger, Firat; Karakuş, Songül

  Blum Blum Shub (BBS) algoritması bilinen güçlü sözde rastgele sayı üreteçlerinden bir tanesidir. Bu algoritma anahtar üretiminde kullanılabilir. BBS temelde iki büyük asal sayının çarpımına ve bir tohum değerine dayanmaktadır. Bu değerlerin seçilmesi oldukça kritik bir konudur. Bu çalışmada bu problemin üstesinden gelmek için yeni bir yaklaşım önerilmiştir. Önerilen yaklaşımda öncelikle asal sayı havuzu oluşturulmaktadır. Bu noktada kullanıcı bir başlangıç ve bitiş değeri belirlemektedir. Belirlenen bu aralıktaki asal sayılar üretilerek bir diziye kaydedilir. Daha sonra bu asal sayı havuzundan kaotik haritalar ile rastgele iki asal sayı seçilir. Seçilen bu asal sayıların dizideki konumları kaydedilir. Tohum değeri ise bu iki asal sayının konumları toplamı olarak ele alınmıştır. Yani seçilecek olan parametreler o an kullanıcının gireceği aralıklarda rastgele bir şekilde seçilecektir. Bu çalışmada bu şekilde rastgele iki bit dizisi elde edilmiştir. Bu diziler 1 milyon bit uzunluğundadır. Elde edilen bu dizilere NIST SP 800-22 testleri uygulanmış olup diziler tüm testleri başarı ile tamamlamıştır.

  AtıfOpenAlex2

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• MakaleAçık Erişim2024/r/munzur/6301
  Automatic Classification of Defective Photovoltaic Module Cells Based on a Novel CNN-PCA-SVM Deep Hybrid Model in Electroluminescence Images

  Imak, Andac

  In today’s world, the rapid development of photovoltaic (PV) power plants has facilitated sustainable energy production. Maintenance and defect detection play crucial roles in ensuring the continuity of energy production. The manual inspection of electroluminescence (EL) images of PV modules requires significant human power and time investment. This study presents a method for the automatic fault detection of PV cells in EL images using hybrid deep features optimized with a principal component analysis (PCA) feature selection algorithm. A lightweight and high-performance model that combines the strengths of convolutional neural network (CNN) architectures was proposed. First, data augmentation techniques were employed owing to the imbalance between the defective and functional classes in the dataset containing EL images. In experimental studies conducted by integrating the PCA algorithm into MobileNetV2, DenseNet201, and InceptionV3 CNN models, accuracy, precision, recall, and F1-score values of 92.19%, 92%, 90%, and 91%, respectively, were achieved. When the results were analyzed, it was observed that the proposed method was effective in detecting faults in PV panel cells.

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  AtıfOpenAlex8·TR Dizin2

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• MakaleAçık Erişim2024/r/munzur/6300
  Effect of Ferro-Alloys on the Properties of High Entropy Alloy with FeCoNiMnMoV Composition Produced by Arc-Melting Method

  Güler, Seval Hale

  In this study, high entropy FeCoNiMnMoV and FeCoNiMn (Ferro Mo-Ferro-V) alloys were produced by arc melting method. After the arc melting process, the samples were annealed at 1000ᵒC under argon atmosphere for 15 hours physical and thermodynamic calculations were performed to determine the properties of the alloy. In the study, both alloys were characterized. For characterization, XRD, SEM, EDS and Micro hardness were taken from the samples. The aim of my study is to examine the effect of using low-priced starting materials on the microstructure of HEA. For this purpose, ferro-alloys were added to the alloy. As a result, similar properties were obtained for the microstructure of both alloys. However, it has been determined that the hardness of samples containing ferro-alloys decreases more due to their chemical composition, especially after heat treatment.

  AtıfOpenAlex3

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• MakaleAçık Erişim2023/r/munzur/6374
  The Effects of Hydroxyapatite on the Corrosion Behaviour of AZ Series Mg Alloys

  Say, Yakup

  Metallic biomaterials are widely used in the orthopedic and dental applications owing to their advanced biocompatibility and sophisticated mechanical properties. Many studies are carried out to develop new alloys with high specific strength, high corrosion resistance and high biocompatibility as an alternative to present metallic biomaterials. Mg alloys are potential alloys as a biomaterial, especially because they have low density and high biocompatibility. However, especially the corrosion properties of Mg alloys need to be improved. In this study, the surfaces of AZ31, AZ61 and AZ91 alloys, which are promising as biomaterials, were coated with hydroxyapatite with high biocompatibility, and the effects of the bioceramics coatings on corrosion resistance were comprehensively investigated. Crack-free and porous surface morphologies were obtained in all bioceramic coatings and the presence of the coatings on the surfaces was supported by EDS analysis. As a result of the corrosion tests performed in SBF, it was determined that the AZ91 alloy had the highest corrosion resistance among the uncoated samples. The hydroxyapatite bioceramic coatings also improved the corrosion properties of all samples. However, among all samples, the highest corrosion resistance was obtained in the hydroxyapatite coated AZ91 alloy.

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  AtıfOpenAlex2

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• MakaleAçık Erişim2023/r/munzur/6373
  Novel Quaternary CuAlZnMg High Temperature Shape Memory Alloy (HTSMA) Fabricated by Minor Batch of Zn and Mg Additions

  Özkul, İskender; Boyrazli, Mustafa; Aksu Canbay, Canan; Başbağ, Güneş; Karaduman, Oktay

  Shape memory alloys (SMAs) constitute the second largest commercial smart material class after piezoelectric materials. Different SMA alloy systems or SMAs with miscellaneous functionalities and characteristic properties have been designed for using in different applications until today. High temperature shape memory alloys (HTSMAs) are also widely desired to be used in various smart materials applications. HTSMAs with different functional and characteristic properties are muchly demanded for different tasks to be done by these alloys or devices designed by these alloys. A common and practical way to fabricate SMAs or HTSMAs with different shape memory effect (SME) and other properties is to fabricate them with different alloying compositions and add different additive elements. In this work, a quaternary CuAlZnMg HTSMA with an unprecedented composition consisting minor amount of zinc and magnesium additives was produced by arc melting method. As a result of applying post-homogenization in high β–phase temperature region and immediate quenching, the microstructural mechanism of a SME property was formed in the produced alloy. After then, to examine SME characteristics of the CuAlZnMg alloy some differential thermal analysis (DTA), microstructural (XRD) and magnetization (VSM) characterization tests were carried out. The DTA results showed that the alloy is a HTSMA exhibiting reverse martensitic transformations at temperature range between 167 °C and 489 °C. The XRD pattern obtained at room temperature revealed the martensite phases formed in the alloy, which phases are the base mechanism of the reversible martensitic transformation (the SME property) of the alloy. The VSM test showed that the alloy exhibit a diamagnetic property with a weak ferromagnetic coercivity contribution.

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• MakaleAçık Erişim2022/r/munzur/6510
  Determination Some Physical Properties of Ground NiMnCoSn Magnetic Shape Memory Alloy Powders

  Say, Yakup; Kanca, M. Sait; Ozan, Ecem

  In this study, NiMnCoSn alloy was produced in the arc melting furnace and then grounded into small powder particles. After this procedure, particles of alloys were pelletized and heat treatment was applied to pellet alloys for 3 different temperatures (500 oC,700 oC and 900 oC). Differential scanning calorimetry (DSC), X-ray diffraction (XRD) and physical property measuring system (PMMS) were used for determining physical properties of samples. The biggest feature of NiMn-based shape memory alloys is that they are magnetically based. The feature that distinguishes magnetic shape memory alloys from traditional ones is that the shape memory effect is magnetic. For this reason, studies of NiMn-based alloys are becoming very popular. It was observed that, grounding procedure is effected all physical properties of NiMnSnCo shape memory alloys, seriously.

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• MakaleAçık Erişim2022/r/munzur/6496
  Investigation of an Outer Rotor In-Wheel Switched Reluctance Motor for Electric Vehicles by Finite Element Method

  Omaç, Zeki

  The demand of fossil fuel vehicles has decreased due to carbon emissions. Recently, electric vehicles (EV) with electric motor propulsion have gotten attention due to their zero carbon emissions and high efficiency. In this study, an outer rotor in wheel switched reluctance motor (IWSRM) with 18 poles on the stator and 24 poles on the rotor, designed for the propulsion of electric vehicles, is investigated in two-dimensional Finite Element Method (FEM). The magnetic field distributions of IWSRM for different rotor positions at nominal current are obtained. Then, the torque and phase inductance are calculated. As a result, the designed IWRSM provided low torque.

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  AtıfOpenAlex1·TR Dizin1

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