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Yayın Modifying the refuse chute design to prevent infection spread: Engineering analysis and optimization(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Tanrıver, Kürşat; Ay, MustafaConsidering the presence of airborne viruses, there is a need for renovation in refuse chutes, regarded as the first step in recycling household waste in buildings. This study aimed to revise the design of existing refuse chutes in light of the challenging experiences in waste management and public health during the coronavirus pandemic. This research primarily focused on the risks posed by various types of coronaviruses, such as the novel coronavirus (COVID-19) and acute respiratory syndrome (SARS and SARS-CoV), on stainless steel surfaces, with evidence of their survival under certain conditions. Refuse chutes are manufactured from stainless steel to resist the corrosive effects of waste. In examining the existing studies, it was observed that Casanova et al. and Chowdhury et al. found that the survival time of coronaviruses on stainless steel surfaces decreases as the temperature increases. Based on these studies, mechanical revisions have been made to the sanitation system of the refuse chute, thus increasing the washing water temperature. Additionally, through mechanical improvements, an automatic solution spray entry is provided before the intake doors are opened. Furthermore, to understand airflow and clarify flow parameters related to airborne infection transmission on residential floors in buildings equipped with refuse chutes, a computational fluid dynamics (CFD) analysis was conducted using a sample three-story refuse chute system. Based on the simulation results, a fan motor was integrated into the system to prevent pathogens from affecting users on other floors through airflow. Thus, airborne pathogens were periodically expelled into the atmosphere via a fan shortly before the intake doors were opened, supported by a PLC unit. Additionally, the intake doors were electronically interlocked, ensuring that all other intake doors remained locked while any single door was in use, thereby ensuring user safety. In a sample refuse chute, numerical calculations were performed to evaluate parameters such as the static suitability of the chute body thickness, static compliance of the chute support dimensions, chute diameter, chute thickness, fan airflow rate, ventilation duct diameter, minimum rock wool thickness for human contact safety, and the required number of spare containers. Additionally, a MATLAB code was developed to facilitate these numerical calculations, with values optimized using the Fmincon function. This allowed for the easy calculation of outputs for the new refuse chute systems and enabled the conversion of existing systems, evaluating compatibility with the new design for cost-effective upgrades. This refuse chute design aims to serve as a resource for readers in case of infection risks and contribute to the literature. The new refuse chute design supports the global circular economy (CE) model by enabling waste disinfection under pandemic conditions and ensuring cleaner source separation and collection for recycling. Due to its adaptability to different pandemic conditions including pathogens beyond coronavirus and potential new virus strains, the designed system is intended to contribute to the global health framework. In addition to the health measures described, this study calls for future research on how evolving global health conditions might impact refuse chute design.Yayın Comparison of classical and heuristic methods for solving engineering design problems(2024) Tanrıver, Kürşat; Ay, MustafaThis paper presents an innovative application of the Ant Colony Optimization (ACO) algorithm to optimize engineering problems, specifically on welded beams and pressure vessels. A simulation study was conducted to evaluate the performance of the new ACO algorithm, comparing it with classical optimization techniques and other heuristic algorithms previously discussed in the literature. The algorithm was executed 20 times to obtain the most efficient results. The best performance outcome in the welded beam simulation was 1.7288, achieved after 540 iterations using 1000 ants, with a computation time of 6.27 seconds. Similarly, the best performance result in the pressure vessel simulation was 5947.1735, obtained after 735 iterations using 1000 ants and completed in 6.97 seconds. Compared to similar results reported in the literature, the new ACO algorithm demonstrated superior performance, offering an outstanding solution. Additionally, users can utilize this new ACO algorithm to quickly acquire information about welded beam design and prefabrication through simulation.Yayın A deep feature driven expert system to estimate the postmortem interval from corneal opacity development(Wiley, 2024) Cantürk, İsmail; Özyılmaz, LalePostmortem interval (PMI) estimation remains an unresolved challenge in forensic science, necessitating practical, reliable andmore accurate tools. This study aimed to develop a quantitative PMI estimation tool that effectively meets these needs. Focusingon the postmortem opacity development of the eye as a key marker for determining time since death, we propose an artificialintelligence-based clinical PMI prediction system utilising computer vision, deep learning and machine learning methods. TheAlexNet algorithm was utilised to extract deep features from the postmortem eye images. Extracted features were then processedby machine learning algorithms. For feature selection, Lasso and Relief techniques were employed, while SVM and KNN wereapplied for classifications. The results were validated using the leave- one-subject-out method. The system was tested across dif-ferent postmortem ranges, providing multi-label predictions. The performance was evaluated using various metrics. The deepfeatures exhibited effective performance in grading postmortem opacity development, achieving state-of-the-art results. Theaccuracy scores were 0.96 and 0.97 for 3-h intervals (i.e., 5-class) and 5-h intervals (i.e., 3-class) experiments, respectively. Theexperimental results indicate that the proposed system represents a promising tool for PMI estimation.Yayın Optimization of properties of iron oxide nanoparticles synthized by solgel method(ISRES Publishing, 2024) Sadullahoğlu, GültenIn this study, the effects of pH value and capping agent on the morphology, pore structure and size of iron oxide nanoparticles were investigated systematically to obtain optimum properties. Iron oxide nanoparticles were synthized by sol-gel method. Polyvinyl alcohol (PVA) was used as capping agent by adding to the solution at 70 °C. After the drying process the powders were heat treated at 250 °C for 2 h under air atmosphere. Particle size of each sample was determined by using ZetaSizer instrument. X-ray diffraction (XRD) technique was employed for structural properties of iron oxide nanoparticles, FE-SEM (Field Emmision Scanning Electron Microscopy) was used to analyze the morphology of the powders. Magnetic properties of the nanoparticles were measured by VSM (Vibrating Sample Magnetometer) under air atmosphere at room temperature. Spesific surface area, porosity and pore size distribution of iron oxide nanoparticles were calculated by Brunauer-Emmett-Teller (BET) instrument. The results indicated that formation of the γ-Fe2O3 is sensitive to either the pH value of the solution or the capping agent, for the uncoated samples when pH value of the solution is adjusted to 2.5, α-Fe2O3 phase was detected as a single phase. When the solution was neutralized, γ-Fe2O3 was formed as the major phase in the microstructure, γ-Fe2O3 phase was formed as the major phase in the PVA coated samples leading to highest value of 50.33 emu/g measured in the sample of PVA8.5. For the PVA coated samples, specific surface area is in the range of 15.73 – 20.81 m2/g, the intervals of pore volume and average pore width are increased to 0.099 – 0.121 cm3/g and 23.19 – 23.07 nm respectively.Yayın Comparison of different machining strategies and their effects on CNC vertical machining center(2024) Öztürk, Ömer Faruk; Tanrıver, Kürşat; Ay, MustafaIn today's world, interest in the aviation sector and developments within it continue to grow at an accelerated pace. With this increase, the demand for the production of components for unmanned aerial vehicles, passenger airplanes, or jet aircraft has risen correspondingly. However, due to the complex structure of aviation parts, the strategy employed during their processing is of significant importance. The distortion issue encountered in the machining of aviation parts, particularly in thin-walled components, leads to unwanted dimensional changes and significantly complicates the production of these parts. This study aims to investigate the effects of different machining techniques on the widely used Al 7075 T7351 aluminum alloy in the aviation sector and to contribute the experimental results to both readers and the literature. In the experiments, samples of Al 7075 T7351 aluminum alloy with thicknesses of 1.00 mm, 1.20 mm, and 1.50 mm were processed using various machining strategies. According to the experimental results, the effect of tool strategy on thickness was observed to vary between a minimum of 0.67% and a maximum of 7.78%. Taking the average of the minimum and maximum values of the three samples, the average effect of the tool path strategy on surface roughness was found to be 55.46%, and its effect on parallelism varied between 37.50% and 112.50%. Furthermore, it is believed that the methods presented in this study will contribute to solving similar problems in other industries, in addition to the aviation sector, in areas such as material selection, determination of processing parameters, and compliance of three-dimensional coordinate measurements (CMM) with standards.Yayın Efficient path planning for drilling processes: The hybrid approach of a genetic algorithm and ant colony optimisation(University of Zagreb, 2024) Tanrıver, Kürşat; Ay, MustafaEfficiency in machining time during drilling is affected by various factors, with one key element being the machining path. Solving the machining path closely resembles the Travelling Salesman Problem (TSP). In this article, drilling on a sample model is simulated using a hybrid algorithm that is developed based on TSP. This hybrid algorithm (GACO) is created by combining the strengths of the Genetic Algorithm (GA) and Ant Colony Optimisation (ACO). Codes written to verify the stability of the algorithms were executed 10 times, and results were recorded indicating the shortest path and machining sequence. Accordingly, the performance of the hybrid GACO algorithm was observed to be 3.16% better than the ACO algorithm in terms of both total path length and total machining time. In terms of computation time, the ACO algorithm lagged behind the GACO algorithm by 6.46%. Furthermore, the hybrid GACO algorithm demonstrated enhanced performance in both total path length and total machining time when compared with the literature. This study aims to contribute to the industry, professionals, and practitioners in this field by providing cost and time savings.Yayın Yılansı robotun tasarımı, statik, dinamik ve modal analizi(Duvar Yayınları, 2023) Coşkun, Yusuf; Aydın, Muhammet; Akdemir, BayramTeknolojinin ilerlemesiyle robotların hayatımıza girmesi ciddi bir şekilde hızlanmıştır. Neredeyse her alanda bu insan yapımı akıllı makinelerden istifade ediyoruz. Arama kurtarma çalışmalarından sanayiye kadar her alanda kullandığımız bu robotlar üzerinde, çalışabilecekleri ortamların zorlu şartlarına fiziki olarak nasıl tepki vereceklerini öğrenmek için gerçek imalattan önce belli analizlerin yapılması önem arz etmektedir. Bu çalışmada yılansı bir robot üzerine çalışılmış, yılansı robotun tasarımı gerçekleştirilmiş ve yılansı robot üretilmeden önce belli analizlere tabi tutulmuştur. Yılansı robot 7 adet eklemden oluşup her eklemi hareketlidir. Sistem tasarımı SolidWorks paket programında gerçekleştirilip sistemin montajı yapılmıştır. Oluşturulan tasarımın fiziksel özellikleri ve parametreleri kullanılarak Matlab ortamında, DenavitHertenberg parametrelerinden yararlanılarak yılansı robotun ileri kinematik sonuçları bulunmuştur. Daha sonra Ansys paket programında üç adet analize tabi tutulmuştur. Bu analizler statik analiz, doğal frekans analizi ve rijit dinamik analizidir. Dar ve pürüzlü yollarda, arama kurtarmada, araştırmalarda kullanılan bu robotların sınır şartları belirlenerek hareketlerinin analiz edilmesi amaçlanmıştır. Bunun sonucunda gerekli parametrelerle analiz gerçekleşmiş ve maksimum çalışma şartları belirlenmiştir.Yayın Two-phase numerical modelling of a wet exhaust system in a catamaran motor yacht diesel engine(2021) Cambaz, Alihan; Görgülü, Yasin Furkan; Arat, HalitIn this study, multiphase temperature distributions and volume fractions through a wet exhaust system were investigated as 3D by using a comprehensive numerical model in a yacht diesel engine. For this purpose, the Volume of Fluid multiphase model was selected as the numerical model. Fuel exhausts are generally located underwater to ensure a modern yacht appearance and minimize exhaust noise. A scoop is positioned above the catamaran yacht exhaust to control water pressure, exhaust gases, and cooling water flow distribution. Besides, two types of fluids have been used, one of which is the hot exhaust gas the other is the cooling water used in the nozzle. The design has been created using Ansys SpaceClaim, and the cooling water is sprayed from the 60° tip of the nozzle. Moreover, the mesh used in the simulation has 1,405,113 elements, 523,125 nodes, and the average mesh skewness is 0.46, the average orthogonal quality of the mesh is 0.64. The Realizable k-ε turbulence model has been used in the simulations. According to the results, the flow fully develops after 1.5 seconds, and the water nozzle sprays the water along the tube cools the exhaust gases. Also, the stagnation points occurring at the elbow fitting of the tube are striking when the velocity contours and velocity vectors are examined.Yayın Thermal analysis of a marine lng tank(UBAK Publications, 2021) Cambaz, Alihan; Görgülü, Yasin Furkan; Arat, HalitThe utilisation of natural gas as a source of energy is gaining popularity. Every year, new reserves are discovered, and there is now considerably more gas being discovered than is being consumed globally. Moreover, new sources are discovered about four times as much gas as it is consumed for every year. However, much of the world's gas reserves are spread out far from major consumption centres. As a result, gas transportation and storage are required. Liquifying the gas at cryogenic temperatures reduces its volume by more than 600 times, making storage and transportation much easier. In this study, thermal analyses were made on the LNG tank on a marine ship (TSR 18009) named “SELVÅG SENIOR” being constructed by SU Ship Design A.Ş. The analyses have been performed as transient-state and the results are projected for 5-day and 10-day time intervals.
