Mühendislik ve Mimarlık Fakültesi
https://hdl.handle.net/20.500.12294/414
Faculty of Engineering and Architecture
2024-03-29T14:42:33Z
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Advanced Bioresin Formulation for 3D-Printed Bone Scaffolds
https://hdl.handle.net/20.500.12294/4075
Advanced Bioresin Formulation for 3D-Printed Bone Scaffolds
Sakarya, Deniz; Zorlu, Tolga; Yucel, Sevil; Sahin, Yesim Muge; Ozarslan, Ali Can
In bone tissue engineering, scaffold attributes such as pore dimensions and mechanical strength are crucial. This study synthesized polycaprolactone dimethacrylate (PCLDMA) from polycaprolactone (PCL), incorporating epichlorohydrin (Epi-PCL) and methacryloyl chloride (Meth-Cl). PCLDMA was blended with polylactic acid (p-PLA) to 3D-print bone scaffolds using stereolithography (SLA). Analytical techniques included nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and compression testing. Degradation kinetics and cell viability were investigated using human osteoblast (HOB) cells. Findings revealed PCLDMA/p-PLA composite scaffold superiority over the original polymers. Notably, PCLDMA-60 (60% PCLDMA, 40% p-PLA) displayed optimal properties. Compressive strength varied from 0.019 to 16.185 MPa, porosity from 2% to 50%, and degradation rates from 0% to 0.4% over three days. Cell viability assays affirmed biocompatibility across various PCLDMA ratios. In conclusion, PCLDMA/p-PLA composite scaffolds, particularly PCLDMA-60, show great potential in bone tissue engineering. © 2024 by the authors.
2024-01-01T00:00:00Z
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The effect of errors in structural system design on the structure damaged in 2023 Turkey earthquakes
https://hdl.handle.net/20.500.12294/4071
The effect of errors in structural system design on the structure damaged in 2023 Turkey earthquakes
Peker, Onder; Altan, Mehmet Fatih
On 6 February 2023, two large earthquakes of Mw 7.7 and 7.6 occurred in the Pazarcik and Elbistan districts of Kahramanmaras province in Turkey, causing extensive structural damage, collapsed buildings and casualties. This study examines a damaged building and presents the relevant repair and strengthening procedures. The importance of design flaws in the structural system, particularly when subjected to horizontal and vertical ground motions, on the performance of the structure is highlighted in this case study. The effects of the interrupted frames and components with unsuitable cross-sectional properties for load transfer within the structure were comprehensively assessed using 3D modelling and on-site investigations. Following repair and strengthening works to improve load transfer, the analysis carried out on the model showed a reduction in LS of approximately 33 % for beams and 45 % for columns. © 2023 Elsevier Ltd
2024-01-01T00:00:00Z
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AutoFusion of feature pruning for decision making in operations research
https://hdl.handle.net/20.500.12294/4066
AutoFusion of feature pruning for decision making in operations research
Atas, Pinar Karadayi; Akyuz, Sureyya Ozogur
Recently, the fusion of algorithms in machine learning studies has taken a lot of attention, emphasizing the power of communal decision-making over-relying on a single decision-maker. One of the crucial questions in the aggregation of algorithms is which and how many models should be combined to achieve both the best accuracy and low complexity. It is already known in machine learning that as the complexity of the model increases too much, prediction accuracy decreases. There is a trade-off between these two features. In order to answer such questions, the diversity notion gets involved in overall consensus models. It is also shown that diversity alone does not determine the best ensemble (fusion), so accuracy and diversity together have been taken into account recently in such problems. We took into account those two notions simultaneously so that the number of algorithms and which algorithms should be in the ensemble is answered while solving the feature selection problems. The proposed method in this work is unique in that it includes an optimization model in the pruning phase, which finds the cardinality of the ensemble optimally. Using this optimization model, the size of the ensemble is found directly from the optimization model, instead of considered as a hyper-parameter. Our study shows a significant improvement in accuracy that achieves 0.702 on average among 8 datasets when compared to an unpruned case of 0.625. These results highlight the efficiency of our method both in model accuracy and in obtaining an optimal model complexity. We have validated our algorithm on different domains of data sets which shows better prediction accuracy values than existing ensemble-based feature selection methods. © 2024, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.
2024-01-01T00:00:00Z
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Calculation of phase diagram and the thermodynamic quantities by the Landau mean field model close to the solid - liquid and solid - solid transitions in n-paraffins
https://hdl.handle.net/20.500.12294/4062
Calculation of phase diagram and the thermodynamic quantities by the Landau mean field model close to the solid - liquid and solid - solid transitions in n-paraffins
Yurtseven, Hamit; Tari, Ozlem
We calculate the phase diagrams and predict the temperature dependence of the thermodynamic quantities at high pressures for the solid - liquid and solid - solid transitions in n-paraffins. This calculation is performed by fitting the phase line equations as obtainedfrom the Landau model to the experimental data from the literature. On thebasis of the Landau model, phase diagram of the solid - solid transition ispredicted at 0.1 MPa for the binary mixtures of n-tridecane + (n-hexane and cyclohexane).For the calculation of the heat capacity the extended mean field is employedfor the n-paraffins studied here. We find that our calculated phase diagrams explain the observed behaviour of the liquid - solid transitions at high pressures in those binary mixtures. Our phase diagrams predicted at 0.1 MPa and our predictions for the thermodynamic quantities can be compared with the experiments for those binary mixtures.
2024-01-01T00:00:00Z