Sakarya University of Applied Sciences AXSIS
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Characterization and kinetics modelling for the titanium silicide layer formed on the Ti6Al4V alloy by pack siliconizing
No full textThe present study reports on silicide coating on Ti6Al4 V alloy by pack siliconizing technique. This siliconizing surface process was carried out in medium consisting of mixture of silicon, alumina, and ammonium chloride at 1000, 1100, and 1200 °C for 2, 4, 6, and 10 h in an argon atmosphere. The presences of outer TiSi2 and the inner TiSi and Ti5Si3 silicide compounds were verified by X-ray anlaysis technique and scanning electron microscope (SEM) equipped with an energy dispersive spectroscope. Depending on process time and temperature, the layer thickness of silicides formed on the surface of substrate materials changes between 9 and 47 μm leading to a diffusion controlled process. The hardness of silicides compounds measured by means of Vickers indenter ranged from 940 to 1647 HV. For silicon diffusion in the silicide compounds an activation energy of 216.27 kJ mol-1 was determined using the integral method. TG-DTA results revealed that silicide coating is stable up to 850 °C. © 2025 Elsevier B.V
Fabrication and characterization of geopolymer-Y2O3 composites: Microstructure, charged particles and neutron shielding properties
No full textRadiation shielding is one major and most effective radiation control measures that is adopted in all radiation facilities. Concrete is a traditional shielding material whose applications has remained popular even in modern nuclear radiation control. The nature of additive(s) is important in modifying the shielding efficacy of geopolymer paste and by extension concrete samples. This research, focuses on the influence of yttria (Y2O3) on the physical, mechanical, and (electrons (e-), protons (p+), alpha particles (α), heavy carbon (C) ions, and fast neutrons) radiation shielding properties of geopolymer (GEO) made from metakaolin. Three batches of the GEO-Y2O3 composite were prepared containing 0, 10%, and 20%, by weight of Y2O3. The densities of the samples were calculated as 2.28, 2.52 and 2.37 g/cm3, while the estimated hardness values were 603, 664 and 649 HV for GEO, GEO-10Y and GEO-20Y samples, respectively. The characteristics cristobalite and mullite peaks of SiO2 observed in the spectrum of GEO was conserved in the Y2O3-doped GEO samples. Comparatively, the stopping powers of e−, p+, α, and C in the GEO-xY follow the order: GEO > GEO-10Y > GEO-20Y At 15 MeV, the value of the projected range in GEO, GEO-10Y, and GEO-20Y is 1410 μm, 1470 μm, and 1610 μm for p+; 128.62 μm, 140.33 μm, and 154.55 μm for α and 13.83 μm, 15.27 μm, and 16.86 μm for C, respectively. The value of ΣR for GEO, GEO-10Y, and GEO-20Y is 0.07495 cm−1, 0.06522 cm−1, and 0.05880 cm−1, respectively. An optimum concentration of 10 wt% of Y2O3 improved the density and hardness of the geopolymer, why the effect of yttria on the shielding behavior of the geopolymer varies with radiation quality. Yttria-doped geopolymer can be used to produce effective particle or fast neutron shielding mortar or concrete. © 2024 Elsevier Lt
Designing green synthesis of silver nanoparticles from Citrus reticulata onto g-C3N4/TiO2 for antibacterial and photocatalytic activities
No full textPreparation of nanoparticles from fruit and plant extracts has been extensively investigated recently due to its environmental friendliness, cost-effectiveness, and minimal use of toxic chemicals for synthesis. This work presents a green method to prepare ternary Ag/g-C3N4/TiO2 nanocomposite via Citrus reticulata extract as a reducing agent. The Ag/g-C3N4/TiO2 composite showed remarkably improved photocatalytic activity for degradation of Rhodamine B compared with TiO2, g-C3N4, and g-C3N4/TiO2 photocatalysts, calculating the degradation rate of Rhodamine B as 91.3% for 120 min under visible illumination. In addition, the antibacterial activities of the prepared samples were examined against six different bacteria, and as a result, it was determined that the Ag/g-C3N4/TiO2 nanocomposite showed strong activity on Escherichia coli (gram negative) and Staphylococcus aureus (gram positive). It is anticipated that the ternary nanocomposite (Ag/g-C3N4/TiO2) developed in this study will be used in many areas due to its antibacterial and photocatalytic properties and will contribute to the easy photocatalytic degradation of organic pollutants and the elimination of pollution. © 2025 Elsevier Lt
Unveiling genetic defense mechanisms: expression analysis of hym, AmNrx1, and CYP9Q3 genes in Varroa-resistant anatolian honey bees
No full textThe Varroa destructor represents a significant threat to honey bees, leading to substantial yield losses and declines in colony health. Defense behaviors, including grooming (auto and allogrooming), serve as crucial mechanisms against Varroa infestations, yet the genetic basis of these behaviors remains elusive. This study examines the expression levels of hymenoptaecin (hym), neurexin-1 (AmNrx1), and CYP9Q3, potentially associated with defense behavior, in colonies of the Muğla honey bee ecotype (Apis mellifera anatoliaca) subjected to a Varroa selection program. Worker bees from 23 control groups and 23 colonies under selection were evaluated by using qPCR analysis. Results reveal a significant upregulation of hym, AmNrx1, and CYP9Q3 genes in the selected group, with fold changes of 2.9, 2.95, and 3.26 respectively compared to controls (p < 0.01). This suggests that selection against Varroa induces alterations in gene expression linked to Varroa exposure behaviors. These findings advocate for the potential use of hym, AmNrx1, and CYP9Q3 genes in preselection for future Varroa-resistant programs in honey bees. Supported by previous studies, these genes may facilitate the establishment of populations with enhanced defense behaviors, such as autogrooming and allogrooming. © The Author(s), under exclusive licence to Springer Nature B.V. 2024
Effect of using ethyl acetate as second fuel in dual fuel diesel engine on engine performance and exhaust emissions; [Çift yakıtlı dizel motorunda ikinci yakıt olarak etil asetat kullanımının motor performansı ve egzoz emisyonları üzerindeki etkisi]
No full textPurpose: This study aims to evaluate the effects of using ethyl acetate as a secondary fuel in a dual-fuel diesel engine on engine performance and exhaust emissions. By examining parameters such as torque, specific fuel consumption, total energy consumption, exhaust temperature, and various emissions (CO, HC, NOx, etc.), the research seeks to determine the potential benefits of ethyl acetate in enhancing combustion efficiency and reducing harmful emissions in diesel engines. Theory and Methods: The study explores the impact of ethyl acetate as a secondary fuel in a dual-fuel diesel engine using experimental methods. The engine was tested at a constant speed of 1800 rpm under varying loads with different ethyl acetate injection durations (1ms, 2ms, and 3ms). Results: Using ethyl acetate as a secondary fuel in a dual-fuel diesel engine significantly affects engine performance and emissions. At full load, ethyl acetate injection resulted in a 72.45% reduction in smoke emissions, a 51.64% decrease in CO emissions, a 1.28% decrease in BSFC, and an increase in combustion efficiency. The findings indicate that ethyl acetate can enhance combustion efficiency and reduce harmful emissions when used alongside diesel fuel, particularly at higher loads (Figure A). Conclusion: Incorporating ethyl acetate as a secondary fuel in dual-fuel diesel engines can significantly enhance combustion efficiency and reduce emissions. The study demonstrates that ethyl acetate injection leads to lower smoke, CO, and HC emissions, as well as reduced BSFC, making it a promising option for cleaner and more efficient diesel engine operation. © 2025 Gazi Universitesi. All rights reserved
Perrin Numbers That Are Concatenations of a Perrin Number and a Padovan Number in Base b
No full textLet (Formula presented.) be a Padovan sequence and (Formula presented.) be a Perrin sequence. Let n, m, b, and k be non-negative integers, where (Formula presented.). In this paper, we are devoted to delving into the equations (Formula presented.) and (Formula presented.), where d is the number of digits of (Formula presented.) or (Formula presented.) in base b. We show that the sets of solutions are (Formula presented.) (Formula presented.) for the first equation and (Formula presented.) for the second equation. Our approach employs advanced techniques in Diophantine analysis, including linear forms in logarithms, continued fractions, and the properties of Padovan and Perrin sequences in base b. We investigate both the deep structural symmetries and the complex structures that connect recurrence relations and logarithmic forms within Diophantine equations involving special number sequences. © 2025 by the author
Evaluation of the structural and radiation transmission parameters of recycled borosilicate waste glass system: An effective material for nuclear shielding
No full textIn the present study, the influence of B2O3 on the mechanical, physical, and radiation-response characteristics of waste borosilicate glass (BSG) is investigated. Four batches of the glass composite containing 0, 40, 50, and 60 wt % of B2O3 each were prepared and labelled as BB0, BB40, BB50, and BB60, respectively, using the popular melt- quench method. Through a series of experimental processes, the glasses' density, hardness, and fracture toughness were measured. The mass attenuation coefficients (MACs), neutron removal cross-sections, and stopping powers of ions in the glasses were estimated using a mixture of Monte Carlo simulations and established theoretical models. By adding boron oxide to the WBSG (BB), a 39.50 % and 38.65 % increase in the density of the glass were observed for BB50 and BB60, respectively. About 9 % improvement was achieved in the hardness of the WBSG reinforced with B2O3. The MAC values were between the ranges of 0.0204-5.4610 cm2/g, 0.193-3.8959 cm2/g, 0.0189-3.4421 cm2/g, and 0.0186-3.0347 cm2/g for BB, BB40, BB50, and BB60, respectively, for gamma photons having energies within 0.015-15 MeV range. Also, the half-value layers for the same gamma photons energy range fell within the ranges of 0.053-14.19, 0.064-12.747, 0.061-10.98, and 0.07-11.226 cm for BB, BB40, BB50, and BB60, respectively. The increase in the boron oxide content in WBSG reduced the effective atomic number of the glass. The present glasses offer cheap and effective alternatives as gamma radiation protection barriers to some recently developed and commercial shielding glasses. The investigated glasses are recommended as cheap, strong, and effective attenuators for gamma, fast neutron, and light and heavy ion radiation
Synthesis, microstructure and radiation protection properties of B2O3–ZnO–K2CO3–PbO ceramic glass system: experimental and theoretical assessment
No full textCeramic glass is a versatile solid-state material engineered to blend the transparency of glass and the thermal stability of ceramics. This fusion has applications in various technological fields with major considerations like radiation protection, durability, heat resistance, and transparency. İn this study, three different B2O3 ceramic glasses comprising varying amounts of ZnO–K2CO3–PbO (BP ceramic glass) were produced, characterized and scanned with electron microscopy. Energy dispersive spectroscopy (EDS) was deployed to find the elemental composition of prepared samples. The radiation protection parameters such as Mass attenuation coefficient (MAC), Linear attenuation coefficient (LAC), Mean free path (MFP), Effective electron density (Neff), Tenth value layer (TVL), Half Value layer (HVL), Effective atomic number (Zeff), Exposure buildup factor (EBF), Equivalent atomic number (Zeq) and Energy absorption build-up factor (EABF) of B2O3–ZnO–K2CO3–PbO (BP) glass–ceramic systems were investigated by using Phy-X/PSD software. The result shows that the micropores increase with an increase in PbO. The density of BP1, BP2, and BP3 were 2.57, 2.36, and 2.19, respectively. The MAC of BP ceramic glass varies as BP1 > BP2 > BP3, implying that BP1 with higher density and greater PbO content is more efficient in radiation protection mostly at lower photon energy. The findings of this research present credible insights applicable to high-performance ceramic glass design for radiation protection in radiotherapy, nuclear power plants, radioactive waste confinement and other related applications. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2025
The effect of surface roughness and carburized depth on wear resistance in 16MnCr5 case hardening steel
No full textPurpose - Today, wear and tear is a metaphor whose cost cannot be ignored by real sector. For this reason, many sectoral and academic studies are carried out to minimize the wear effect. This study aims to create a perspective against wear problems for the automotive industry as well. Design/methodology/approach - The 16MnC5 material, which is used as the U-joint material in the powertrain of the automotive industry, was subjected to heat treatment such as normalization and carburization at certain temperatures and duration. By subjecting the resulting carbide thickness to the abrasion process, the maximum effective heat treatment parameters against wear were determined. Findings - It has been determined that the ideal cementation condition for 16MnCr5 steel to be used in the wear system is carburized samples at 900 degrees C for 3.5 h with a hardness depth of 1.04 mm. Originality/value - The variation in which the surface hardness thickness and surface roughness obtained by different heat treatment variations of the U-joint part, which is one of the cardan shaft components that provide power transmission of heavy commercial vehicles, show the best wear resistance, were investigated. As a result of this study, the study is to prevent the waste of limited materials in the world and to reduce the repair and maintenance costs of commercial vehicles
Can artificial intelligence understand our emotions? Deep learning applications with face recognition
No full textObjective: The aim of this study is to evaluate the ability to detect emotions from human facial expressions via facial recognition technologies and analyze the effectiveness of deep learning models in this process. Method: This research was conducted between 01.04 and 01.07.2024. The data of the study were taken from the open access site https://www.kaggle.com/datasets/msambare/fer2013 (Kaggle, 2024). Python 3.8 is used in this study. The FER-2013 (Facial Expression Recognition 2013) dataset is a comprehensive collection of facial images labeled with various emotions. The dataset contains 35,887 grayscale facial images. Each image has a size of 48 × 48 pixels. The dataset consists of images belonging to 7 emotion categories: anger, disgust, fear, happy, sad, confused, and neutral. Results: In our experiments on the FER2013 dataset, we evaluated the performance of three different models: MobileNetV3-L, EfficientNetV2-L, and our proposed EfficientMobileNet. The evaluation criteria were based on sensitivity, specificity, accuracy, and F1 scores to assess the effectiveness of each model comprehensively. The EfficientMobileNet model outperformed MobileNetV3-L and EfficientNetV2-L in all measured performance metrics. EfficientMobileNet was the most successful model for predicting emotions, with an accuracy of 77.6%. Conclusion: The impressive results obtained by EfficientMobileNet on the Fer2013 dataset show potential for wider application, especially in image classification tasks involving low-quality or small-scale images. This performance supports the idea of the potential for further improvements in neural network architecture and model efficiency and accuracy. Future work should focus on optimizing the model for more challenging datasets, studying the impact of different architectural adjustments, and investigating the scalability of EfficientMobileNet across various domains and applications. © The Author(s) 2025