WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collections

Permanent URI for this collectionhttps://hdl.handle.net/20.500.13091/2

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The 2-Adic Valuation of Shifted Padovan and Perrin Numbers and Applications
(Tubitak Scientific & Technological Research Council Turkey, 2024) Bravo, Eric; Irmak, Nurettin
We characterize the 2-adic valuation of (Pn - 1) n >= 0 , where ( P n ) n >= 0 denotes the Padovan sequence. In addition, we use this formula to find all the Cullen and Proth numbers that are Padovan numbers. We also fully describe the 2-adic order of (Rn + 1) n >= 0 , where ( R n ) n >= 0 denotes the Perrin sequence, and use it to find all Woodall and Proth numbers of the second kind which are Perrin numbers. As a consequence we find that 3 , 5 , 9 , and 65 are the only Fermat numbers in the Padovan sequence; while 3 and 7 and 2 and 5 are the only numbers of Mersenne and Th & acirc;bit ibn Kurrah in the Perrin sequence respectively.
3D Printable Mortars with Green Materials: Sustainable Solutions with Nanocellulose
(Taylor & Francis Ltd, 2025) Turk, Ayse; Turk, Furkan; Edebali, Serpil; Keskin, Ulku Sultan
This study aims to improve the fresh and hardened properties of 3D-printable mortars. For this purpose, mortar mixtures containing cellulose nanofibres (CNF) obtained from the green algae of the Cladophora sp., which is abundant in lakes and causes environmental pollution if not recycled, as well as commercially available cellulose nanocrystals (CNC) and welan gum (WG) were prepared. The results showed that CNF was the most effective additive in improving fresh-state rheology, increasing yield stress by approximately 6 times and thixotropy by 48 times compared to the reference sample. Additionally, the CNF-modified mortar could carry a load of 50 N in the fresh state. The CNC additive showed the best mechanical performance, increasing compressive strength by 12%. Cellulosic additives were also observed to reduce shrinkage. Nanocellulose additives also increased the interlayer adhesion strength. All additives used have improved the properties of 3D-printable mortars. This study successfully produced a 3D-printable concrete/mortar additive from Cladophora sp., an environmentally detrimental waste material.
A-Who: Stagnation-Based Adaptive Metaheuristic for Cloud Task Scheduling Resilient to DDoS Attacks
(MDPI, 2025) Kaplan, Fatih; Babalik, Ahmet
Task scheduling in cloud computing becomes significantly more challenging under Distributed Denial-of-Service (DDoS) attacks, as malicious workload injection disrupts resource availability and degrades Quality of Service (QoS). To address this issue, this study proposes an improved Wild Horse Optimizer (A-WHO) that incorporates a stagnation detection mechanism and a stagnation-driven adaptive leader perturbation strategy. The proposed mechanism dynamically applies a noise-guided perturbation into the stallion position only when no improvement is observed over a predefined threshold, enabling A-WHO to escape local optima without modifying the standard behavior of WHO in normal iterations. In addition, a DDoS-aware CloudSim environment is developed by generating attacker virtual machines and high-MI malicious cloudlets to emulate realistic resource exhaustion scenarios. A-WHO's performance is assessed using makespan, SLA violation rate, each of the QoS metrics, and energy consumption on normal and DDoS conditions. The experimental results indicate that A-WHO achieves the best absolute makespan and QoS metrics during an attack and competitive results under normal conditions. In comparison with the WHO, PSO, ABC, GA, SCA, and CSOA, the proposed approach demonstrates improved robustness and greater resilience to resource degradation attacks. These findings indicate that integrating stagnation-aware diversification into metaheuristic schedulers represents a promising direction for securing cloud task scheduling frameworks.
Citation - WoS: 11
Citation - Scopus: 15
Accuracy Assessment of Dems Derived From Multiple Sar Data Using the Insar Technique
(SPRINGER HEIDELBERG, 2021) Karabörk, Hakan; Makineci, Hasan Bilgehan; Orhan, Osman; Karakuş, Pınar
In this study, digital elevation models (DEMs) derived from AlosPalsar data (Japanese Space Agency-JAXA), Sentinel-1A data, and Envisat ASAR data (European Space Agency-ESA) were compared by using a global navigation satellite system (GNSS). In addition, AW3D30, SRTM, and ASTER GDEM (open-access DEMs) data were also included in the accuracy evaluation. The DEM accuracies were investigated in three different terrain types, namely a plain area, mountainous area and agricultural area, and compared at elevation values on a pixel-based. The accuracy obtained from the ALOS PALSAR satellite data was found to be more reliable for all three terrain types. The standard deviation and root mean square values were calculated and compared to each other. The results of the accuracy assessments showed that the best result for the plain area was obtained with the Sentinel-1A and SRTM data, for the mountainous area was obtained with the SRTM data and for agricultural area was obtained with the ALOS PALSAR and SRTM data.
Citation - WoS: 1
Citation - Scopus: 1
An Accurate and Novel Numerical Simulation With Convergence Analysis for Nonlinear Partial Differential Equations of Burgers-Fisher Type Arising in Applied Sciences
(Walter De Gruyter Gmbh, 2022) Kürkçü, Ömür Kuvanc; Sezer, Mehmet
In this study, the second-order nonlinear partial differential equations of Burgers-Fisher type are considered under a unique formulation by introducing a novel highly accurate numerical method based on the Norlund rational polynomial and matrix-collocation computational system. The method aims to obtain a sustainable approach since it contains the rational structure of the Norlund polynomial. A unique computer program module, which involves very few routines, is constructed to discuss the precision and efficiency of the method and these few steps are described via an algorithm. A residual function is employed in both the error and convergence analyses with mean value theorem for double integrals. The considered equations in the numerical tests stand for model phenomena arising widely in applied sciences. Graphical and numerical comparisons provide a clear observation about the consistency of the method. All results prove that the method is highly accurate, eligible, and provides the ultimate operation for aforementioned problems.
Citation - WoS: 12
Citation - Scopus: 17
Acoustic-Driven Airflow Flame Extinguishing System Design and Analysis of Capabilities of Low Frequency in Different Fuels
(Springer, 2022) Taşpınar, Yavuz Selim; Köklü, Murat; Altın, Mustafa
Traditional fire extinguishing methods can harm people and nature. For this purpose, in this study, no harmful acoustic-driven airflow fire extinguishing system was developed and experiments were carried out to extinguish gasoline, kerosene, thinner (synthetic thinner) liquid fuels and liquid petroleum gas (LPG) flames. 17,442 extinguishing experiments were conducted in 5 different flame sizes, 54 different frequencies and 10 cm to 190 cm distance range. The data obtained were analyzed using the polynomial regression method. For liquid fuels, the frequencies of 10 Hz to 50 Hz at a distance of 10 cm to 100 cm, 10 Hz to 32 Hz at a distance of 100 cm to 150 cm, and 10 Hz to 28 Hz at a distance of 150 cm to 180 cm are effective extinguishing ranges. LPG fuel, 10 Hz to 45 Hz at a distance of 10 cm to 140 cm, frequencies of 15 Hz to 30 Hz at a distance of 140 cm to 180 cm are effective extinguishing ranges. In addition, caused by the compression of the woofers membrane inside the collimator and the injected airflow at frequency of 30 Hz reduced the 12 cm diameter metal plate from 86.2 degrees C to 18.8 degrees C in 5 min, and the metal plate left to cool down from 80 degrees C to 21.7 degrees C in 10 min at a distance of 100 cm. The average Mean Square Error value obtained as a result of polynomial regression analysis is 0.9544, and the Root Mean Square Error value is 1.2020.
Adaptation and Validation of the Post-Pandemic Health Promotion Behavior of Young Adults in the Digital Age (ps-Sgd) Scale in the Turkish Population
(MDPI, 2024) Koç, Mustafa Can; Yıldırım, Elif; Özdurak Singin, Rabia Hürrem; Talaghir, Laurentiu-Gabriel; Iconomescu, Teodora Mihaela; Karakaş, Neşe
Background: Young adulthood is a critical developmental period in which individuals establish life-long health behaviors and take responsibility for their own health care. Health promotion strategies tailored to young adults, leveraging digital tools, and addressing challenges exacerbated by events like the COVID-19 pandemic are needed. The aim of this study was to adapt the post-pandemic health promotion behavior of young adults in the digital age (PS-SGD) scale to the Turkish population in order to assess and compare the health behavior of young adults after the pandemic. Methods: A total of 312 participants, aged between 19 and 29 years, were included in the study via non-probabilistic criterion sampling, while the Turkish adaptation process started with translation and back translation methods performed with three language and two health science experts. For statistical analysis, EFA and CFA were conducted to evaluate internal consistency and structural validity. Confirmatory factor analysis was utilized to confirm the structure of the six sub-dimensions. Additionally, measurement invariance was examined regarding participants' gender to determine if the scale accurately captured similar traits across diverse groups. The relationship between the test-retest data was tested by Pearson correlation to measure consistency and its invariance over time. Results: The gender distribution of the sample was found to be 61.3% female and 38.7% male. According to the results of EFA, items 8 and 18 were removed from the Turkish-adapted version. As a result of the reliability analysis conducted with the Turkish version of the scale, the Cronbach alpha coefficient was obtained as 0.851 for the post-pandemic health promotion behavior. Additionally, the scale was rated as reliable with the following Cronbach alpha values: 0.79 for the personal hygiene, 0.78 for dietary habits, 0.72 for using mobile devices, 0.70 for emotional health, 0.68 for health care and physical activity, and 0.51 for social health sub-dimensions. To examine the six sub-dimension factor structures of the scale, fit indices were calculated as chi 2/df (1.722), GFI (0.894), IFI (0.908), TLI (0.892), CFI (0.907), RMSEA (0.048), and SRMR (0.057) and were within acceptable limits. Findings of the multi-group confirmatory factor analysis for measurement invariance were less than or equal to 0.01 for the triangle CFI and triangle RMSEA values across all indices. Consequently, it was observed that the item-factor structure, factor loadings, variances, covariances, and error variances of the scale were equivalent for both male and female young adults, while test-retest results showed a high positive correlation. Conclusions: The Turkish version of the post-pandemic health promotion behavior scale of young adults in the digital age scale, consisting of 25 items and six subscales, was proven to be a valid and reliable tool to measure health promotion behavior in young adults aged 19-29 years.
Citation - WoS: 24
Citation - Scopus: 40
An Adaptive Method for Traffic Signal Control Based on Fuzzy Logic With Webster and Modified Webster Formula Using Sumo Traffic Simulator
(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2021) Ali, Muzamil Eltejani Mohammed; Durdu, Akif; Çeltek, Seyit Alperen; Yılmaz, Alper
In the past, the Webster optimal cycle time formula was limited to calculate the optimal cycle from historical data for fixed-time traffic signal control. This paper focuses on the design of an adaptive traffic signal control based on fuzzy logic with Webster and modified Webster's formula. These formulas are used to calculate the optimal cycle time depending on the current traffic situation which applying in the next cycle. The alternation of the traffic condition between two successive cycles is monitored and handled through the fuzzy logic system to compensate the fluctuation. The obtained optimal cycle time is used to determine adaptively the effective phase green times i.e. is used to determine adaptively the maximum allowable extension limit of the green phase in the next cycle. The SUMO traffic simulator is used to compare the results of the proposed adaptive control methods with fuzzy logic-based traffic control, and fixed-time Webster and modified Webster-based traffic control methods. The proposed methods are tested on an isolated intersection. In this study, real field-collected data obtained from three, four, and five approaches intersections in Kilis/Turkey are used to test the performance of the proposed methods. In addition, to examine the efficiency of the proposed techniques at heavy demands, the arbitrary demands are generated by SUMO for a four approaches intersection. The obtained simulation results indicate that the proposed methods overperform the fixed time and fuzzy logic-based traffic control methods in terms of average vehicular delay, speed, and travel time.
Citation - WoS: 5
Citation - Scopus: 6
Adrenal Tumor Characterization on Magnetic Resonance Images
(WILEY, 2020) Barstuğan, Mücahid; Ceylan, Rahime; Asoğlu, Semih; Cebeci, Hakan; Koplay, Mustafa
Adrenal tumors occur on adrenal glands and are generally detected on abdominal area scans. Adrenal tumors, which are incidentally detected, release vital hormones. These types of tumors that can be malignant affect body metabolism. Both of benign and malign adrenal tumors can have a similar size, intensity, and shape, this situation may lead to wrong decision during diagnosis and characterization of tumors. Thus, biopsy is done to confirm diagnosis of tumor types. In this study, adrenal tumor characterization is handled by using magnetic resonance images. In this way, it is wanted that patient can be disentangled from one or more imaging modalities (some of them can includes X-ray) and biopsy. An adrenal tumor image set, which includes five types of adrenal tumors and has 112 benign tumors and 10 malign tumors, was used in this study. Two data sets were created from the adrenal tumor image set by manually/semiautomatically segmented adrenal tumors and feature sets of these data sets are constituted by different methods. Two-dimensional gray-level co-occurrence matrix (2D-GLCM), gray-level run-length matrix (GLRLM), and two-dimensional discrete wavelet transform (2D-DWT) methods were analyzed to reveal the most effective features on adrenal tumor characterization. Feature sets were classified in two ways: benign/malign (binary classification) and type characterization (multiclass classification). Support vector machine and artificial neural network classified feature sets. The best performance on benign/malign classification was obtained by the 2D-GLCM feature set. The best results were assessed with sensitivity, specificity, accuracy, precision, and F-score metrics and they were 99.17%, 90%, 98.4%, 99.17%, and 99.13%, respectively. The highest classification performance on type characterization was obtained by the 2D-DWT feature set as 59.62%, 96.17%, 93.19%, 54.69%, and 54.94% for sensitivity, specificity, accuracy, precision, and F-score metrics, respectively.
Citation - WoS: 18
Citation - Scopus: 24
Adsorption of Cr(vi) Onto Cross-Linked Chitosan-Almond Shell Biochars: Equilibrium, Kinetic, and Thermodynamic Studies
(SPRINGER INTERNATIONAL PUBLISHING AG, 2021) Altun, Türkan; Ecevit, Hüseyin; Kar, Yakup; Çiftçi, Birsen
In this study, to remove Cr(VI) from the solution environment by adsorption, the almond shell was pyrolyzed at 400 and 500 degrees C and turned into biochar (ASC400 and ASC500) and composite adsorbents were obtained by coating these biochars with chitosan (Ch-ASC400 and Ch-ASC500). The resulting biochars and composite adsorbents were characterized using Fourier transform infrared (FTIR) spectroscopy; Brunauer, Emmett, and Teller (BET) surface area; scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX); and the point of zero charge pH (pH(pzc)) analyses. The parameters affecting the adsorption were examined with batch adsorption experiments and the optimum parameters for the efficient adsorption of Cr(VI) in 55 mg L-1 solution were determined as follows; adsorbent dosages: 5 g L-1 for biochars, 1.5 g L-1 for composite adsorbents, contact time: 120 min, pH: 1.5. It was seen that the temperature did not affect the adsorption much. Under optimum conditions, Cr(VI) adsorption capacities of ASC400, ASC500, Ch-ASC400, and Ch-ASC500 adsorbents are 11.33, 11.58, 37.48, and 36.65 mg g(-1), respectively, and their adsorption percentages are 95.2%, 97.5%, 94.3%, and 94.0%, respectively. Adsorption data were applied to Langmuir, Freundlich, Scatchard, Dubinin-Radushkevic, and Temkin isotherms and pseudo-first-order kinetic model, pseudo-second-order kinetic model, intra-particle diffusion model, and film diffusion model. The adsorption data fitted well to the Langmuir isotherm and pseudo-second-order kinetic models. From these results, it was determined that chemical adsorption is the dominant mechanism. Also, both intra-particle diffusion and film diffusion is effective in the adsorption rate. For all adsorbents, the Langmuir isotherm proved to be the most appropriate model for adsorption. The maximum monolayer adsorption capacities calculated from this model are 24.15 mg g(-1), 27.38 mg g(-1), 54.95 mg g(-1), and 87.86 mg g(-1) for ASC400, ASC500, Ch-ASC400, and Ch-ASC500, respectively. The enthalpy change, entropy change, and free energy changes during the adsorption process were calculated and the adsorption was also examined thermodynamically. As a result, adsorption occurs spontaneously for all adsorbents.
Citation - WoS: 42
Citation - Scopus: 49
Adsorption of Malachite Green and Methyl Violet 2b by Halloysite Nanotube: Batch Adsorption Experiments and Box-Behnken Experimental Design
(Elsevier Ltd, 2022) Altun, Türkan; Ecevit, Hüseyin
Dyes constitute a significant part of the pollutants in industrial wastewater. In this study, halloysite nanotube (HNT) was used for adsorption of malachite green and methyl violet 2B dyes from the solution. Using batch adsorption experiments and response surface method, parameters affecting adsorption have been optimized. As a consequence of the batch experiments, after 60 min, the adsorption equilibrium state was achieved at 3 g L?1 HNT dosage, 125 mg L?1 dye concentration and natural solution pH. Temperature did not significantly affect the adsorption. The adsorption equilibrium data can be said to have fitted the Langmuir, Freundlich, Dubinin-Radushkevich and Temkin isotherms well for the both dyes. The Langmuir maximum monolayer malachite green and methyl violet 2B adsorption capacities (As) of HNT are 74.95 mg g?1 and 67.87 mg g?1, respectively. Adsorption processes are more consistent with the pseudo-second-order kinetic model. In addition, both intra-particle diffusion and film diffusion are effective as rate-determining steps in adsorption. Thermodynamic calculations showed that the adsorption is exothermic and spontaneous. The regeneration of HNT after adsorption was confirmed in five cycles. By using the Box-Behnken response surface method, the parameters affecting the adsorption process were modeled, the effects of these parameters on the adsorption efficiency were expressed mathematically and the optimum operating parameters were determined. © 2022
Citation - WoS: 30
Citation - Scopus: 32
Adsorptive Removal of Malachite Green Dye From Aqueous Solution by Ion Exchange Resins
(Springer Science and Business Media Deutschland GmbH, 2023) Yanardağ, D.; Edebali, S.
The adsorption of malachite green dye by commercially available synthetic polymers Diaion CR-11 and Amberlite IRC-748 resins has been studied. The effect of the initial dye concentrations, adsorbent dosage, contact time, pH, and temperature were examined. The dye adsorption mechanism for both resins was investigated using Langmuir, Freundlich, Scatchard, and Dubinin-Radushkevich (D-R) isotherm models. Also, experimental data were applied to the pseudo-first-order and pseudo-second-order kinetic models. The Langmuir isotherm and pseudo-second-order kinetic model best fit to the equilibrium data showed maximum adsorption capacities of 102.1 mg/g and 480.6 mg/g for Diaion CR-11 and Amberlite IRC-748, respectively. Thermodynamic studies show that the adsorption of malachite green dye increases with temperature and indicates that the adsorption process of both resins is endothermic. The negative value of change in Gibbs free energy shows spontaneous adsorption of malachite green on both resins. The polymer resins are characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscope (SEM). © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
Advances in UAV Operations for Valley-Type Mapping with Different Duration Period PPP-AR Methods in GCP
(MDPI, 2025) Bilgen, Burhaneddin; Makineci, Hasan Bilgehan; Bulbul, Sercan
This study evaluates the performance of the Precise Point Positioning with Ambiguity Resolution (PPP-AR) method under varying durations and software platforms in determining the optimal placement of Ground Control Points (GCPs) for use in photogrammetric products generated by Unmanned Aerial Vehicles (UAVs) over valley-type rugged terrain. In the field experiment, six GCPs and twenty checkpoints were established, and GNSS measurements with 5-s intervals were collected for 2 h at the GCPs. The collected GNSS data were segmented into 3-min and 10-min intervals, and PPP-AR-based solutions were generated for the complete datasets as well as for the 3- and 10-min subsets. The software tools used for PPP-AR processing included CSRS-PPP, Pride PPP-AR, PPP Arisen, and raPPPid. Eleven photogrammetric models were constructed using the coordinates obtained, and their accuracies were assessed using the checkpoints. The results indicate that, in terms of horizontal accuracy, the best performance was achieved using CSRS-PPP and Pride PPP-AR with 10-min observation durations. The static GNSS method yielded the most precise results for vertical accuracy, while among PPP-AR solutions the 10-min CSRS-PPP application demonstrated superior performance. Additionally, models were generated using only three GCPs placed according to different strategies, revealing that satisfactory levels of accuracy can be achieved when GCPs are strategically positioned. This study demonstrates that the PPP-AR method can be reliably utilized for high-accuracy GCP acquisition within short durations, even in challenging terrain conditions.
Citation - WoS: 1
Citation - Scopus: 1
Advancing Perovskite Solar Cells: Inorganic CCTS Hole-Transporting Material for Enhanced Efficiency and Stability
(Elsevier, 2025) Sari, Fahriye; Ozel, Sultan Suleyman; Sarilmaz, Adem; Ozel, Faruk; Kus, Mahmut; Ersoz, Mustafa
One of the most effective methods for generating renewable energy is the efficient conversion of photons into electrical energy using environmentally sustainable materials. In recent years, the integration of chalcogenide materials, which exhibit graphene-like semiconducting properties and high charge carrier mobility, into perovskite solar cells (PSCs) has garnered significant attention for enhancing the performance, stability, and ecofriendly nature of these devices. In this study, Cu2CoSnS4 (CCTS) nanocrystals were synthesized and utilized as a fully inorganic hole transport layer (HTL) in inverted PSCs. Devices incorporating 6 vol% CCTS achieved a power conversion efficiency (PCE) of 10.07 %, and retained 93 % of their initial efficiency after 720 h under inert storage conditions, without encapsulation. This demonstrates a notable improvement in stability compared to conventional PEDOT: PSS-based devices. The optimized CCTS HTL provided better energy level alignment, reduced moisture ingress, and enhanced charge transport. These findings indicate that CCTS is a promising inorganic HTL candidate for efficient and stable PSCs.
Citation - WoS: 25
Citation - Scopus: 29
Aerogels as Promising Materials for Antibacterial Applications: a Mini-Review
(ROYAL SOC CHEMISTRY, 2021) Kaya Güzel, Gülcihan; Aznar, Elena; Deveci, Hüseyin; Martinez-Manez, Ramon
The increasing cases of bacterial infections originating from resistant bacteria are a serious problem globally and many approaches have been developed for different purposes to treat bacterial infections. Aerogels are a novel class of smart porous materials composed of three-dimensional networks. Recently, aerogels with the advantages of ultra-low density, high porosity, tunable particle and pore sizes, and biocompatibility have been regarded as promising carriers for the design of delivery systems. Recently, aerogels have also been provided with antibacterial activity through loading of antibacterial agents, incorporation of metal/metal oxides and via surface functionalization and coating with various functional groups. In this mini-review, the synthesis of aerogels from both conventional and low-cost precursors is reported and examples of aerogels displaying antibacterial properties are summarized. As a result, it is clear that the encouraging antibacterial performance of aerogels promotes their use in many antibacterial applications, especially in the food industry, pharmaceutics and medicine.
Citation - WoS: 5
Citation - Scopus: 7
Alternative Approach for Safe Disposal of Dry Olive Pomace: Pyrolysis With/Without Physical Preprocessing
(SPRINGER, 2020) Dinç, Gamze; Yel, Esra
The aim of this study is to present an alternative approach for disposal by using pyrolysis for dry olive pomace (which is the leftover portion of raw olive pomace), which constitutes a problem in olive oil production facilities. In this context, dry olive pomace was pyrolyzed at 600 degrees C and two different pyrolysis durations: 5 degrees C/min heating rate without retention (total pyrolysis duration is 80 min) and 1 degrees C/min heating rate with 30-min retention after reaching target pyrolysis temperature (total pyrolysis duration is 550 min). Afterward, the effects of the dry olive pomace mixed with the olive mill wastewater and the pomace particle size during the pyrolysis process were evaluated in terms of pyrolysis product yields, inorganic contents of chars and organic fractions of bio-oil. While mixing of pomace within the wastewater resulted in an increase in the pyrolysis liquid, the effects of pomace particle size on pyrolysis product yields changed based on the pyrolysis conditions. A decrease in the particle size from 2 to 0.85 mm resulted in an increase in gas by 37.3% and a decrease in liquid by 37% at the pyrolysis process of 80 min. Furthermore, the decrease in the pomace size in grinding preprocess enhanced pyrolysis liquid quality in terms of a decrease in oxygenated compounds by 5-13% and an increase in aliphatic compounds by 7-20% at both pyrolysis durations. Consequently, dry olive pomace pyrolysis can be stated as one of the effective alternatives for safe disposal by converting waste into useful end products. Graphic abstract
Citation - WoS: 2
Citation - Scopus: 3
Alternative Green Application Areas for Olive Pomace Catalytic Pyrolysis Biochar Obtained Via Marble Sludge Catalyst
(Springer, 2024) Göktepeli, Gamze; Özgan, Afra; Önen, Vildan; Ahmetli, Gülnare; Kalem, Merve; Yel, Esra
Evaluating industrial wastes in the system with minimum preprocessing and generation economically valuable products from them have critical importance. In this regard, especially cheap, wieldy, and readily available catalysts have been researched to increase variety of useful products in pyrolysis systems, to reduce process time, and to increase quality and diversity of products. Therefore, in this study, marble sludge (named K1) was evaluated as catalyst at different dosages (10%, 20%, 30%, 50%) and pyrolysis temperatures (300, 500, 700 degrees C) in olive pomace (OP) pyrolysis and; the potential green applications of produced new biochars at new usage areas with different purposes based on characteristics were investigated. ANOVA test results showed that temperature and catalysts ratio had significant effect on pyrolysis product yields since significance value for K1 and temperature was lower than 0.05 for pyrolysis products. OP-K1 biochars had alkaline properties and high earth metal quantities. Moreover, increment in K1 ratio and temperature resulted in decrement of the biochar surface acidity. Therefore, it can be indicated that these biochars can have a potential usage for anaerobic digestion processes, lithium-ion batteries, and direct carbon solid oxide fuel cell (DC-SOFC) but further electrochemical property test should be performed. Moreover, produced biochars can be alternative fuels in some processes instead of coal since they have low S content and high heat values. Consequently, it is foreseen that produced biochars will have an important place in the development of potential usage areas with a new and environmentally friendly approach in different areas apart from the conventional uses of catalytic pyrolysis chars.
Citation - WoS: 9
Citation - Scopus: 10
Alternative System Design for High Temperature Solid Particle Erosion Wear Problem
(SPRINGER/PLENUM PUBLISHERS, 2021) Demirci, Musa; Bağcı, Mehmet
In order to simulate the wear behavior of materials subjected to solid particle erosion due to high temperature as well as velocity effect in operating conditions such as power plants and jet engines, ASTM G76 standard is not sufficient and test rig compliant with ASTM G211-14 standard must be put forward. In this context, a test rig, alternative to existing systems where solid particle erosion wear experiments can be performed in compliance with high temperature (similar to 700 degrees C) and particle impact velocity (similar to 150 m/s) conditions, has been designed and produced. In order to ensure the widespread use of this test rig, a resistance wire system was used to reach high temperatures of the heating system by achieving a different design solution. In the setup of this design, the perfect gas equation, heating power and ohm laws are also used. In addition, the designs of specimen fixture and particle feeding system, which are the determining parameters in erosion wear tests, have been updated. With the produced test rig; solid particle erosion experiments were carried out using Inconel 718 test specimens at 600 degrees C temperature, similar to 97 m/s erosive particle impact velocity and three different erosive particle impact angles (30 degrees, 60 degrees and 90 degrees). In the experiments, especially the change of temperature over time was confirmed by the data obtained from both the test rig and the specimens. Graphic
Citation - WoS: 3
Citation - Scopus: 6
Analysis of Machine Learning Classification Approaches for Predicting Students' Programming Aptitude
(MDPI, 2023) Çetinkaya, Ali; Baykan, Ömer Kaan; Kırgız, Havva
With the increasing prevalence and significance of computer programming, a crucial challenge that lies ahead of teachers and parents is to identify students adept at computer programming and direct them to relevant programming fields. As most studies on students' coding abilities focus on elementary, high school, and university students in developed countries, we aimed to determine the coding abilities of middle school students in Turkey. We first administered a three-part spatial test to 600 secondary school students, of whom 400 completed the survey and the 20-level Classic Maze course on Code.org. We then employed four machine learning (ML) algorithms, namely, support vector machine (SVM), decision tree, k-nearest neighbor, and quadratic discriminant to classify the coding abilities of these students using spatial test and Code.org platform data. SVM yielded the most accurate results and can thus be considered a suitable ML technique to determine the coding abilities of participants. This article promotes quality education and coding skills for workforce development and sustainable industrialization, aligned with the United Nations Sustainable Development Goals.
Citation - WoS: 9
Citation - Scopus: 10
An Analysis of Terrestrial Water Storage Changes of a Karstic, Endorheic Basin in Central Anatolia, Turkey
(Elsevier B.V., 2023) Köycegiz, C.; Sen, O.L.; Buyukyildiz, M.
Water budget components of endorheic basins of semi-arid and karstic characters are difficult to assess. In this study, we attempt to estimate the water budget components of the Konya Endorheic Basin (KEB), which is a semi-arid, karstic basin in central Anatolia, using The Gravity Recovery and Climate Experiment mission (GRACE) observations and Global Land Data Assimilation System (GLDAS) data over the period 2002-2019. We also investigate the trends and sub-trends in the time series of the hydrometeorological parameters. The results indicate that the available water potential in the basin has a decreasing trend over the study period. Precipitation and evapotranspiration show increasing trends in the basin, however, the other hydrometeorological parameters demonstrate decreasing trends. Both Terrestrial Water Storage Anomaly (TWSA) and groundwater level decrease significantly (20.21 mm/yr and 122.34 mm/yr, respectively). The dry 2008 and subsequent wet year created a hydrological breaking point in the time series. The weights of soil moisture and groundwater storages are relatively large amongst the TWSA components (49.61% and 33.12%, respectively). The surface water storage anomaly comes at the third place with a 14% weight. It is assessed that the groundwater storage system responds to precipitation with a delay of 6 months. Limestone zones respond more sharply to groundwater depletion than alluvial zones. It should be noted that the GRACE and GLDAS data could be used together to successfully estimate the water budget components for sustainable management of the limited water resources of the basin. © 2023

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