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Öğe Energy management in microgrids using model-free deep reinforcement learning approach(Institute of Electrical and Electronics Engineers (IEEE), 10-01-2025) Talab, Odia A.; Avci, IsaElectric power systems are undergoing rapid modernization driven by advancements in smart-grid technologies, and microgrids (MGs) play a crucial role in integrating renewable energy sources (RESs), such as wind and solar energy, into existing grids. MGs offer a flexible and efficient framework for accommodating dispersed energy resources. However, the intermittent nature of renewable sources, coupled with the rising demand for Electric Vehicles (EVs) and fast charging stations (FCSs), poses significant challenges to the stability and efficiency of microgrid (MG) operations. These challenges stem from the uncertainties in both energy generation and fluctuating demand patterns, making efficient energy management in MG a complex task. This study introduces a novel model-free strategy for real-time energy management in MG aimed at addressing uncertainties without the need for traditional uncertainty modeling techniques. Unlike conventional methods, the proposed approach enhances MG performance by minimizing power losses and operational costs. The problem is formulated as a Markov Decision Process (MDP) with well-defined objectives. To optimize decision-making, an actor-critic-based Deep Deterministic Policy Gradient (DDPG) algorithm is developed, leveraging reinforcement learning (RL) to adapt dynamically to changing system conditions. Comprehensive numerical simulations demonstrated the effectiveness of the proposed strategy. The results show a total cost of 51.8770 €ct/kWh, representing a reduction of 3.19% compared to the Dueling Deep Q Network (Dueling DQN) and 4% compared to the Deep Q Network (DQN). This highlights the robustness and scalability of the proposed model-free approach for modern MG energy management.Öğe Evaluation of antibacterial and biocompatibility of radiopaque bioactive glass-based endodontic cements(Elsevier, 2025-01-06) Saud, A. Najah; Koç, Erkan; Özdemir, Olcay; Cetin Y.; Yildizhan Y.This study evaluated the antibacterial properties, hemocompatibility, cytotoxicity, and genotoxicity of bioactive glass ceramic-based endodontic cement formulated with various radiopaque active ingredients with varying concentrations (0, 15, and 20 wt%). Antibacterial activity against E. faecalis was assessed using colony-forming unit (CFU) assays. The results showed significant antimicrobial activity of the bioactive glass-based cement, which was enhanced by adding radiopaque active ingredients. Lanthanum oxide exhibited the highest antibacterial activity at a concentration of 20 %, reducing the CFU count from 6,000,000 (control) to 1,190,000. Bismuth oxide and samarium oxide also showed dose-dependent improvements in antibacterial properties. Hemocompatibility analysis revealed that all cement samples, including those containing radiopaque agents, remained nonhemolytic after 1-h- and 24-h incubation, indicating excellent compatibility with human blood. Cell viability testing with the L929 cell line showed that the cement samples achieved the required cell viability threshold of 70 % according to ISO 10993–5:2009 over 1, 3, and 7 days of exposure. Genotoxicity assessment using comet assay revealed no detectable DNA damage in the cement samples compared to the negative control. These comprehensive results confirm the biocompatibility and strong antibacterial properties of the bioactive glass ceramic-based endodontic cement samples containing various radiopacity agents.Öğe Blockchain for cybersecurity: architectures and challenges(CRC Press, 2024-01-01) Avci, Isa; Koca, MuratBlockchain technology is a sophisticated database technique that facilitates the transparent exchange of information among a network of businesses. The blockchain database is designed to store data by organizing it into blocks that are interconnected in a chain-like structure. A blockchain may be defined as a cryptographic and digitally recorded register or list that securely stores data. In the context of blockchain technology, data is kept in a series of interconnected blocks arranged sequentially, like a chain. Each block has a timestamp identifying the moment of recording, along with the data that is to be registered in the registry. The data is documented in a manner that ensures accessibility and verifiability for all individuals, with the ability for anyone to get a duplicate of the register. The use of blockchain technology guarantees the transparent and safe storage of documents, eliminating the need for a centralized authority. This report provides a comprehensive analysis of the blockchain architecture. This study focuses on the analysis of the security mechanisms used in the blockchain system, with particular emphasis on the comparative evaluation of the four primary blockchain designs. The study focused on the analysis of blockchain applications concerning their implications for cybersecurity and then identified and evaluated their advantages and constraints. Furthermore, a comprehensive analysis has been conducted on the primary cybersecurity dangers that may arise inside these apps.Öğe Search for Aflatoxin M1 in Raw Milk and Butter Samples(ABADER (Adıyaman Bilimsel Araştırmalar Derneği), 2024-12-15) Hizo, Mohammed Nooruldeen Saeed; Solmaz, Hasan; Uçkun, MiraçIn this study, the presence of aflatoxin M1 (AFM1) in raw milk of cows, sheep, goats, buffalo, and cow butter offered for consumption in some settlements in Turkey and Iraq in the Spring of 2022 was investigated and, taking into account legal regulations, it was determined whether it poses a danger to human health. Toxin contents in milk were compared between these sampling points. In the study, 50 raw cow milk, 60 raw sheep milk, 30 raw goat milk, 30 raw buffalo milk, and 40 butter samples were collected and AFM1 presence was analyzed by ELISA method. It was observed that the AFM1 level in the dark and goat milk samples collected from Ankara was statistically significantly higher than those collected from Mosul but did not exceed the European Union and Turkish Food Codex (TFC) limits (50 ng/kg). AFM1 levels in buffalo milk and cow butter sampled from Mosul were observed to be statistically significantly higher than those sampled in Kayseri and Ankara, respectively, and exceeded the TFC limits. It was determined that the AFM1 level of cow milk samples from Ankara and Mosul exceeded the TFC limit. As a result, since the presence of AFM1 detected in buffalo milk, cow milk, and cow butter samples collected from Mosul and cow milk samples collected from Ankara is important for public health, agricultural products used as feed in these regions should be selected correctly, stored under appropriate conditions, routinely analyzed for aflatoxin, and strictly inspected. Furthermore, the organization of training programs on good agricultural practices aimed at educating livestock breeders and milk and dairy product producers and raising producer and consumer awareness are believed to safeguard public healthçÖğe Frenkel effect in thin film semiconductor-polymer based composites(International Organization on 'Technical and Physical Problems of Engineering, 2024-12-01) Ahadzade, Shafaq Mirbaba; Hashimov, Arif Mamed; Nurubeyli, Tarana Kamil; Mammadova, Gulshan Nuraddin; Asgarov, Khangardash AdigozelIn the article, the influence of the Frenkel effect, in other words, the electrical conductivity of nonlinear resistances, on the shape of the potential barrier formed between two semiconductor crystallites in semiconductorpolymer composite varistors was studied. Also, the value of the Frenkel coefficient and the shape of the potential barrier were determined. In Si-polymer-based composites, the value of electrical conductivity was calculated, and graphs of the dependence of the electrical conductivity on the intensity of the electric field were constructed. It is known from the parameters established in the PooleFrenkel coordinate that the dependence corresponds to the Poole-Frenkel theory of thermofield ionization. Also, using this dependence, the value of the Frenkel coefficient was found. Conductivity mechanisms in Si-polymer based composites have been studied. Based on the results obtained, the features of heat transport in the studied samples are explained within the framework of the following models: Schottky emission in the high temperature region, tunnel field emission in large gaps and the mechanism of heat transfer from traps at low temperatures. In this case, different mechanisms of heat transfer change in different temperature ranges and at different values of electrical work. Knowing the shape of the potential barrier in composites, it is possible to determine the spatial distribution of charges near dopant centers or traps. Taking this into account, the forms of potential fences, which allow us to evaluate the parameters of the catchment centers (traps) of cargo carriers, have been determined. It is known that the increase in the percentage of the dispersant leads to a decrease in the height of the potential barrier.Öğe Optimization planning techniques with meta-heuristic algorithms in IoT: performance and QoS evaluation(Sakarya University, 2024-08-31) Koca, Murat; Avcı, İsaBig data analysis used by Internet of Things (IoT) objects is one of the most difficult issues to deal with today due to the data increase rate. Container technology is one of the many technologies available to address this problem. Because of its adaptability, portability, and scalability, it is particularly useful in IoT micro-services. The most promising lightweight virtualization method for providing cloud services has emerged owing to the variety of workloads and cloud resources. The scheduler component is critical in cloud container services for optimizing performance and lowering costs. Even though containers have gained enormous traction in cloud computing, very few thorough publications address container scheduling strategies. This work organizes its most innovative contribution around optimization scheduling techniques, which are based on three metaheuristic algorithms. These algorithms include the particle swarm algorithm, the genetic algorithm, and the ant colony algorithm. We examine the main advantages, drawbacks, and significant difficulties of the existing approaches based on performance indicators. In addition, we made a fair comparison of the employed algorithms by evaluating their performance through Quality of Service (QoS) while each algorithm proposed a contribution. Finally, it reveals a plethora of potential future research areas for maximizing the use of emergent container technology.Öğe Wind speed prediction by utilizing geographic information system and machine learning approach: A case study of Karabük province in Türkiye(Taylor & Francis, 2024-12-22) Gürsoy, Emrehan; Gürdal, Mehmet; Gedik, EnginThis study analyzed wind speed data for years in Karabük province, Türkiye, using an Artificial Neural Network (ANN) with a Multilayer Perceptron (MLP) feed-forward network. The Bayesian Regularization algorithm was employed, a well-known training algorithm for Multi-Layer Perceptron (MLP) networks. The study investigated the relationship between wind speed and various meteorological parameters such as month, air temperature, relative humidity, and air pressure. The results obtained from the ANN model provided a reliable methodology for predicting future wind speed values in Karabük province. To evaluate the performance of the ANN model, metrics such as Mean Absolute Error (MAE), Average Relative Deviation (ARD), Mean Squared Error (MSE), and R-squared (R2) were utilized. The ANN model demonstrated its efficacy by revealing the highest average wind speeds of 2.7 m/s in Safranbolu province during August, with corresponding MAE, ARD%, MSE, and R2 performance metrics of −0.029, −0.380%, 0.0028, and 0.999, respectively. The maximum measured and predicted Mean Wind Speed (MWS) values were identified in different months across various locations, specifically in August for Eflani, July for both Eskipazar and Karabük CC and September for Safranbolu. Notably, the highest recorded MWS was observed at 42.8 m/s in Eskipazar during July, while the lowest MWS was recorded at 16.4 m/s in Eskipazar in October. Besides, by employing Geographic Information System (GIS) analysis, the average wind speeds were ranked for different districts, with Safranbolu, Eflani, Eskipazar, and Karabük CC having the highest to lowest wind speeds, respectively.Öğe SEF: A smart and energy-aware forwarding strategy for NDN-based internet of healthcare(Tech Science Press, 2024) Askar, Naeem Ali; Habbal, Adib; Hamouda, Hassen; Alnajim, Abdullah Mohammad; Khan, SherozNamed Data Networking (NDN) has emerged as a promising communication paradigm, emphasizing content-centric access rather than location-based access. This model offers several advantages for Internet of Healthcare Things (IoHT) environments, including efficient content distribution, built-in security, and natural support for mobility and scalability. However, existing NDN-based IoHT systems face inefficiencies in their forwarding strategy, where identical Interest packets are forwarded across multiple nodes, causing broadcast storms, increased collisions, higher energy consumption, and delays. These issues negatively impact healthcare system performance, particularly for individuals with disabilities and chronic diseases requiring continuous monitoring. To address these challenges, we propose a Smart and Energy-Aware Forwarding (SEF) strategy based on reinforcement learning for NDN-based IoHT. The SEF strategy leverages the geographical distance and energy levels of neighboring nodes, enabling devices to make more informed forwarding decisions and optimize next-hop selection. This approach reduces broadcast storms, optimizes overall energy consumption, and extends network lifetime. The system model, which targets smart hospitals and monitoring systems for individuals with disabilities, was examined in relation to the proposed strategy. The SEF strategy was then implemented in the NS-3 simulation environment to assess its performance in healthcare scenarios. Results demonstrated that SEF significantly enhanced NDN-based IoHT performance. Specifically, it reduced energy consumption by up to 27.11%, 82.23%, and 84.44%, decreased retrieval time by 20.23%, 48.12%, and 51.65%, and achieved satisfaction rates that were approximately 0.69 higher than those of other strategies, even in more densely populated areas. This forwarding strategy is anticipated to substantially improve the quality and efficiency of NDN-based IoHT systems. CopyrightÖğe Sentiment analysis comparisons across selected ml models: application on Malaysia online banking twitter data(Elsevier, 2024) Fadhil, Intan Sorfina Mohd; Yusof, Mohammad Hafiz Mohd; Khalid, Ilyani Abd; Teoh, Sian Hoon; Almohammedi, Akram A.Sentiment analysis study predominantly revolves around classification tasks by Machine Learning. None of these studies had demonstrated the comparative analysis between different type of ML models accuracy level. On the other hand, the banking industry is rapidly embracing digitalization and security-related matters like trust and privacy remain critical factors in influencing customer's acceptance and usage towards those services. Hence, sentiment analysis serves as a powerful tool for banks to gauge customer satisfactory level towards these security services. However, this process is done previously without optimizing the selection of ML models accuracy level. Furthermore, the results are often invisible and kept in manual book. Hence the ultimate goal of this study is to comparatively measure the accuracy performance of different type of ML sentiment analysis accuracy against the Malaysia online banking security services Twitter data (a.k.a X). Subsequently, the report will be visualized through web application. It is done in six-fold methodology namely data collection, data pre-processing and data wrangling, data analysis, model training and finally model testing and evaluations. The result shows Decision tree has achieved the highest accuracy of 76%.Öğe An enhanced approach to red mud (RM) sustainable management and utilization for marl stabilization considering the dynamic response and durability analysis(Elsevier, 2025-07) Vakili, Amir Hossein; Salimi, Mahdi; Keskin, İnan; Onur, Mehmet İnanç; Tabaroei, Abdollah; Dadgar, MohammadhosseinMarl soil, known for its high calcite content, presents significant challenges in construction projects due to its low strength and poor durability, especially under varying moisture conditions. In wet environments, marl often exhibits rapid disintegration, compromising stability and limiting its use in geotechnical applications. On the other hand, the worldwide disposal of red mud (RM) waste, an industrial by-product of alumina processing, has resulted in significant environmental concerns and substantial financial burdens. This study investigates the potential of RM for enhancing the mechanical, dynamic, and durability characteristics of marl soil under both dry and wet conditions. The experiments included the unconfined compressive strength test (UCS), Brazilian tensile strength test (BTS), bender element test (BET), long-time soaking test, as well as a set of microstructural analyses. The findings indicated that the UCS of the samples containing 30 % RM increased by 3.6 and 6.83 times after curing periods of 7 and 28, respectively, reaching an acceptable strength level even under wet conditions. Furthermore, RM was found capable of postponing the development of cracks and sustaining the integrity of the sample over the long term. RM treatment also improved the dynamic properties, increasing shear wave velocity by 127.9 % and reclassifying the soil from Class F (very weak) to Class D (very stiff) under seismic loading criteria. However, RM introduced brittle behavior to the treated samples, resulting in reduced axial strain and a 60–70 % drop in strength under wet conditions. Future research should focus on addressing these limitations by incorporating additional stabilizing agents. This study highlights the potential of RM for sustainable soil stabilization, offering an effective approach to managing industrial waste while enhancing marl's performance in geotechnical applications.Öğe A comprehensive review on sustainability in EDM process of additive manufactured materials(Elsevier, 2025-03) Şentürk, Erhan; Alparslan, Cem; Bayraktar, Şenol; Korkmaz, Mehmet Erdi; Günay, MustafaSustainability aims to leave a better world to future generations where they can be self-sufficient in every field and by producing without endangering the present and the future. Sustainability, which is a very broad concept, is generally evaluated under three main headings that are not independent of each other; environmental protection, social development and economic growth. Considering these concepts, each of the production stages, from raw material to the final product, is important for dealing with the ever-increasing needs. With sustainable production, the use of raw materials, waste generation resulting from production, energy consumption and the formation of hazardous chemicals during production can be reduced. Thus, environmentally friendly and economical production can be achieved. Rapidly advancing and developing production technologies bring innovative solutions in sustainable production for various applications. Today, developing technology to overcome the constraints in production methods and increase production quality, Additive manufacturing (AM) and electrical discharge machining (EDM) methods come to the fore in strategic industrial production areas for example aerospace, defense, automotive and health. Through the utilization of AM, sustainable and next-generation intelligent production can be realized by overcoming conventional manufacturing constraints, including material wastage, challenges in fabricating intricate geometries, and dependency on specialized tooling. A wide variety of materials such as Al-based alloys, stainless steel, Inconel and Ti6Al4V alloys are widely used in metal AM. Although AM components are produced in a near-net shape, subsequent post-production treatments are still necessary to meet the stringent requirements of critical industrial applications. EDM, a non-contact machining process that will minimally affect workpiece performance and reduce material waste, enables the processing of parts produced with AM. The ability to easily process electrically conductive materials that are difficult to process with traditional machining has expanded the usage area of this method. However, the EDM process of these materials raises concerns about sustainability due to factors such as energy consumption and environmental impact. AM and EDM find use in the production and processing of important materials used in the industrial field, but the development of EDM processes applied to AM materials for sustainable production continues. In this review research, it is aimed to comparatively reveal the sustainability characteristics of Al and nickel-based (Ni) alloys, stainless steels and Ti alloy in the AM process. The literature review indicates substantial progress in enhancing the energy efficiency of EDM operations, especially via the creation of environmentally sustainable dielectric fluids and energy-optimized milling techniques. These developments illustrate viable methods for diminishing the environmental impact of EDM, exactly corresponding with the aim of the study.Öğe The role of stair-rod dislocations on the twinning and martensitic transformation in single crystalline NiCoCr(Acta Materialia, 2025-03-15) Picak, SezerHigh- and medium-entropy alloys are a sub-class of multi-principal element alloys with an exceptional combination of strength and toughness arising from twinning– and transformation–induced plasticity. The underlying mechanisms responsible for the nucleation of deformation twinning and ɛ-martensite transformation in multi-principal element alloys still remains under intense debate. In this work, high-resolution transmission-electron microscopy was used to reveal the complex dislocation reactions behind deformation twinning and ɛ-martensite in a model NiCoCr. The existence of stair-rod and Shockley partials under uniaxial loading was demonstrated. The stair-rods dislocations with multiple Lomer-Cottrell locks play a crucial role in the formation of deformation twinning and ɛ-martensite. Lomer-Cottrell locks significantly contribute to work hardening behavior by acting as both dislocation barriers and sources. The results herein offer clarity regarding the strengthening mechanisms in multi-principal element alloys.Öğe Role of different type nanoparticles on exergy, thermoeconomic, exergoeconomic, environmental, and enviroeconomic indicators in a CI engine fueled with rapeseed oil biodiesel(Elsevier, 2025-03-15) Gülcan, Halil Erdi; Bayindirli, Cihan; Erol, Derviş; Çelik, MehmetThis present study conducts energy, exergy, thermoeconomic, exergoeconomic, environmental, and enviroeconomic analyses for a CI engine fuelled with rapeseed oil biodiesel that includes varying proportions of TiO2, Ag2O, and CeO2 nanoparticles. Experiments are performed on four different engine torques (between 10 Nm and 40 Nm engine torque ranges) and 1800 1/min shaft speed. The addition of nanoparticles to 100 % rapeseed oil biodiesel (R100) fuel positively impacts energy, exergy, thermoeconomic, and exergoeconomic results. Among all the test fuels, the best energy, exergy, thermoeconomic, and exergoeconomic performance results are obtained with the R + Ti75 fuel containing 75 ppm TiO2, followed by the R + Ce75 and R + Ti50 fuels. The R + Ti75 and R + Ce75 fuels reduce exergy destruction by an average of 7 % and 5.5 % respectively compared to the R100 fuel, while increasing exergy efficiency by an average of 5 % and 4 %. Additionally, the maximum reduction in capital cost (reduction in thermoeconomic impact) is achieved with the R + Ti75 fuel, with an average reduction of approximately 12 %. On the other hand, the lowest environmental impact is obtained with the R100 fuel, while the highest environmental impact is observed with the R + Ti75 and R + Ce75 fuels. In conclusion, the most efficient blends in terms of energy, exergy, thermoeconomic, and exergoeconomic aspects are the R + Ti75 and R + Ce75 fuels.Öğe On fractal cubic network graphs(Elsevier, 2025-03) Altintas Tankul, Ayse Nur; Selcuk, Burhan; Turan, Muhammed KamilThe fractal cubic network graphs (FCNG), previously studied by Karci and Selcuk (2015), are reviewed in this paper. First, general information about FCNG is provided, and new topological properties of FCNG are presented. Simulations of the topological properties of FCNG, hypercube, and 2D square meshes have been performed, and the results are introduced. Secondly, a strategy for the routing problem for FCNG is presented. A new strategy for the routing path of FCNG is presented and explained with an example, and a recursive algorithm using this strategy is presented. Thirdly, a strategy for the shortest path problem for FCNG with a similar routing strategy is also presented, and a recursive algorithm for this strategy is given. An algorithm for mapping network nodes on a 2D plane and an algorithm for computing the minimum distance connection point between fractals used to construct the shortest path are also provided. These algorithms are illustrated with an example. The running times of the algorithms are also calculated.Öğe Mushrooms for mushrooms: a bio-based approach to active food packaging(Springer Nature, 2024-11-28) Karanfіl, Mustafa; Doğan, Nurcan; Akgul, Yasin; Doğan, Cemhan; Ahmed, Salih BirhanuIn this study, carbon dots (CDs) were synthesized from Pleurotus ostreatus liquid culture and incorporated into polyvinyl alcohol (PVA) and chitosan (Chi) nanofibers, fabricated via the electroblowing technique to create an active packaging material. TEM analysis confirmed that the synthesized CDs possessed uniform size and morphology, while UV-Vis spectroscopy validated their optical properties. SEM imaging revealed that the electroblown nanofibers had a smooth surface morphology and uniform distribution of CDs within the PVA-Chi matrix. The nanofibers also exhibited enhanced thermal stability, as determined by thermogravimetric analysis (TGA). The developed CD-PVA-Chi nanofiber packaging was applied to oyster mushrooms, where it significantly reduced weight loss by over 50%, inhibited microbial growth by approximately 60%, and preserved 80% of the mushrooms’ firmness over a 6-day storage period compared to control packaging. The cytotoxicity tests confirmed that the packaging material was non-toxic, making it safe for food contact applications. This study demonstrates that the CD-PVA-Chi nanofiber packaging is a promising, eco-friendly alternative to conventional packaging materials, with potential for extending the shelf life of perishable foods through its bioactive properties and scalability for industrial production.Öğe A multi-criteria optimization for a radial heat sink with semicircular fins based on the design of experiments approach(Elsevier BV, 2025-02) Hussein, Yousif Hashim; Tahseen, Ahmad Tahseen; Akroot, Abdulrazzak; Mithu, M.A.H.; Abdulateef, Ammar M.Radial fins play a crucial role in enhancing energy efficiency and supporting sustainable industrial practices by optimizing heat transfer, aligning with the Sustainable Development Goals (SDGs). Addressing the need for high-efficiency systems to reduce greenhouse gas emissions, this study highlights the importance of optimizing factors in a General Factorial Design (GFD). Factors were coded and scaled within the range of +1 to −1, accounting for variations in the units of independent variables. This study utilized the Nusselt number and thermal resistance, along with an effective regression analysis, to develop a novel predictive model. Key performance indicators included R2, adjusted R2, predicted R2, coefficient of variation (CV), and parameter separation from the best-fit results. The proposed model demonstrated remarkable accuracy in predicting the Nusselt number, with values of R2, predicted R2, adjusted R2, and CV at 98.15 %, 97.08 %, 94.87 %, and 2.44 %, respectively. For thermal resistance, the corresponding values were 97.91 % for predicted R2, 96.70 % for adjusted R2, 94.21 % for CV, and 3.33 % for parameter separation. Therefore, it is evident that the proposed model is highly accurate in predicting semicircular radial heat sink performance, offering a robust tool for future heat sink designs and sustainable thermal management systems.Öğe The Effect of Soil and Foliar Nitrogen Applications On Cd Toxicity of Durum Wheat (Triticum turgidum L.) Grown in Low and High Cadmium Contaminated Soils(Springer Science and Business Media LLC, 2024-12-18) Ete Aydemir, Özlem; Kocaman, Ayhan; Korkmaz, Kürşat; Özkutlu, FarukA pot experiment was conducted in the greenhouse condition to investigate Cd tolerance of wheat in cadmium containing soils (0.5 and 5.0 mg Cd kg−1), taking into account the effect of N fertilization. The study investigates the effect of N application and foliar application of urea on cadmium uptake and accumulation in durum wheat and evaluates its effects on physicochemical properties. The results of this study showed a very significant positive correlation between increasing plant Cd concentration and increasing N supply. That an adequate amount of CaNO3− fertilizer in the soil together with foliar application of urea statistically increased plant biomass of durum wheat and in parallel increased Cd accumulation. In terms of plant biomass, the increase in very low nitrogen (50 mg N kg-1) application (S1) to the (0.5 mg Cd kg−1) contaminated soil application was 187.70%, and 259.09% for Sufficient nitrogen (200 mg N kg−1) application (S2) to the (0.5 mg Cd kg−1) contaminated soil, when compared to the No nitrogen application (SC) to the soil (Control) application. Upon foliar urea application, increases were recorded as 90.78% for Foliar application with urea only, no nitrogen applied (FC) to soil, 216.57% for Foliar urea with very low nitrogen application (F1) to the soil (50 mg N kg−1), and 298.01% for Foliar urea with sufficient nitrogen application (F2) to the soil (200 mg N kg−1) compared to SC. Similarly, Cd concentration in durum wheat increased with higher nitrogen application, with increases observed as 16.93% for S1, 42.28% for S2, 26.14% for FC, 34.65% for F1, and 58.11% for F2 compared to SC. Consequently, it was also the foliar application of urea together with the supply of nitrate that increased the bioavailability of Cd and decreased its toxic effect. The amount of N fertilizer not only promotes plant growth and increases plant biomass, but also increases the accumulation of Cd in the shoot.Öğe Effectuality of frequency dependent dielectric characterization of (N:DLC) film deposition between the metal-semiconductor interface(Elsevier BV, 2025-02) Urgun, N.; Tan, S.O.; Feizollahi, Vahid A.; Avar, B.; Altındal, Ş.Dielectric characterization of metal-interlayer-semiconductor (MIS) structures of N-doped Diamond-Like Carbon (N:DLC) film-coated interlayer is performed to assess their dielectric properties, AC electrical conductivity (σac), and polarization mechanisms. The interlayer's structural analysis is performed using Scanning Electron Microscopy (SEM) and X-ray Photo-electron Spectroscopy (XPS). The in-phase and out-of-phase parts of the complex dielectric constant (ε∗), the complex electric modulus (M∗), the values of tangent loss (tanδ), and σac are determined utilizing admittance-voltage (Y = 1/Z = G + jωC) measurements revealing that their strong sensitivity to voltage and frequency. Remarkably, a relative permittivity (ε′) of 407 at 1 kHz, 104 times higher than traditional SiO2 insulators, is observed, suggesting a significantly enhanced electron density and energy storage capacity for ultracapacitors. The double logarithmic σac vs f plot slope changes between 0.36 and 0.20 at strong accumulation. The intersection point in σac implies a lack of free electrons at higher frequencies, suggesting an electron trapping or recombination process.Öğe Optimization of performance and emission characteristics of a diesel engine fueled with MgCO3 nanoparticle doped second generation biodiesel from jojoba by using response surface methodology (RSM)(Elsevier BV, 2025-02) Savaş, Arif; Uslu, Samet; Şener, RamazanAs the availability of diesel fuel, derived from finite fossil resources, depletes and its combustion releases harmful emissions, the search for alternative fuels becomes increasingly critical. One of the most influential alternative fuels is biodiesel. In this study, the biodiesel was produced from jojoba, a second-generation plant that humans do not consume as food. Then, MgCO3 nanoparticles were added to this biodiesel, and the performance and emission experiments were carried out in a single-cylinder diesel engine. The engine was tested at six different loads (0.5, 1, 1.5, 2, 2.5, and 3 kW) and with the addition of nanoparticles (50, 100 and 150 ppm). Finally, the experimental data were optimized using Response Surface Methodology (RSM). Engine loads and fuel compositions were determined as input parameters. Carbon dioxide (CO2), nitrogen oxides (NOx), hydrocarbons (HC), carbon monoxide (CO), brake thermal efficiency (BTE), and brake specific fuel consumption (BSFC) were determined as output parameters. RSM optimization seeks to find the optimal operating point that minimizes emissions and BSFC while maximizing BTE. In the RSM results, the R2 value was calculated as a minimum of 95.95 % and a maximum of 99.42 %. The error rate in all parameters increased below 10 %. The highest error was in the HC value, which was 7.25 %. As a result of the optimization, the optimum value was reached under 74.20 ppm and 1.4 kW load. In these values, BTE, BSFC, NOx, CO2, HC, and CO values were calculated as 23.67 %, 376.27 g/kWh, 393.83 ppm, 4.28 %, 7.63 ppm, and 0.038 %, respectively.Öğe Compatibility of melamine formaldehyde- and polycarboxylate-based superplasticizers on slag/sintering ash-based geopolymer paste(Elsevier, 2025-01-10) Tekin, İlker; Pekgöz, Mahfuz; Saleh, Noora Khasro; Kiamahalleh, Mohammad Valizadeh; Gholampour, Aliakbar; Gencel, Osman; Ozbakkaloglu, TogayThe high viscosity of a geopolymer based on fresh slag/ash represents a notable drawback in terms of workability. This research delves into the potential advantages of incorporating a superplasticizer to address the low workability of geopolymers. Innovatively, geopolymer pastes were formulated using energy production system ash (EPA) and ground granulated blast furnace slag (GGBFS), alongside melamine formaldehyde and polycarboxylate-based superplasticizers (SPs). Furthermore, paste formulations incorporated maximized emission reduction of sintering (MEROS) ash (SA), a by-product of the steel industry. Flow table and marsh funnel time tests were conducted to assess the impact of 1 %, 2.5 %, and 5 % SPs and SA on fresh-state behavior of the geopolymer pastes. Comprehensive examinations of physical, mechanical, and morphological characteristics of the geopolymer pastes were undertaken under two conditions: without and with NaOH (at various NaOH concentrations). The findings indicate that, the presence of SPs has minimal impact on the workability of the pastes. However, when the NaOH is used instead of the Na2SiO3 at 10 %, inclusion of 1 % polycarboxylate-based (PCE), melamine formaldehyde-based (MF) SPs and SA results in a dramatic decrease in the marsh funnel time by 12, 8.5 and 5.3 times, respectively. While the inclusion of 1 % PCE and MF increases the 28-day compressive strength of the geopolymer paste by about 48 % and 4 %, respectively, the addition of 1 % SA causes a significant improvement in the 28-day compressive strength by about 87 % under NaOH-free condition. When 10 % NaOH is used, an increase in the SPs content from 0 % to 5 % leads to a reduction in compressive strength, while the use of 5 % SA leads to an increase in 7-, 28-, and 90-day compressive strength by approximately 33 %, 35 %, and 16 %, respectively. Microstructure analysis reveals that geopolymer gels such as calcium aluminum silicate hydrate and sodium aluminum silicate hydrate can contain sulfur derived from the admixtures. The use of SA not only improves mechanical properties but also promotes sustainable utilization of industrial by-products in construction materials.
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