Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collections
Permanent URI for this collectionhttps://hdl.handle.net/20.500.13091/3
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Article Thermo-Mechanical Characterization of GFRP Molded Grating Composites Exposed to Elevated Temperatures(MDPI, 2026) Özkılıç, Yasin Onuralp; Özgün, Muhammed İhsan; Madenci, Emrah; Aksoylu, CeyhunThis study comprehensively investigates the thermal and mechanical degradation behavior of molded glass-fiber-reinforced plastic (GFRP) grating composites subjected to temperatures ranging from 80 °C to 320 °C. Three types of industrially produced GFRP gratings—open-type (OG), thin closed-skin (CG), and thick closed-skin (TCG)—were evaluated using mechanical, microstructural, chemical, and crystallographic analyses. Three-point bending tests revealed that TCG-type specimens exhibited superior thermal resistance, experiencing only a 43.9% loss in strength at 320 °C, whereas OG-type specimens showed significant resin degradation, fiber–matrix decomposition, and microcrack formation at temperatures above 200 °C. Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) analyses revealed significant resin degradation, fiber–matrix decomposition, and microcrack formation. Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) confirmed substantial mass loss and structural disintegration at temperatures above 200 °C. Dynamic Mechanical Analysis (DMA) results revealed that the glass transition temperature (Tg) occurred at approximately 115–120 °C. The second-order regression model developed to estimate flexural strength under increasing temperature provided high accuracy (R2 > 0.99) for all grating types. It should be noted that this investigation focuses on the short-term thermo-mechanical response under fundamental flexural loading to provide an accurate baseline for preliminary engineering design. The findings emphasize that the effect of temperature should be considered a critical parameter in the structural design of GFRP systems, especially in industrial environments with temperatures above 120 °C. Accordingly, tables for material selection and load-carrying capacity should be recalibrated to account for short-term temperature effects.Article Sustainability Assessment: Environmental Impacts and Economic Performance of Bio-Based and Mineral-Based Cutting Fluids(Wiley, 2026) Oksuz, Secil Tutar; Tutar Oksuz, Secil; Divarci, Aybala BetulAbstract Machining is an important manufacturing process that can cause significant environmental impacts, particularly in terms of energy consumption, waste generation, and emissions. This study evaluates the environmental performance of two types of cutting fluids, bio‐based and mineral‐based, using a comprehensive life cycle assessment (LCA). A comparative analysis is conducted to quantify emissions associated with each fluid, assess their contributions to selected environmental impact categories, and examine the related economic aspects. The aim of this study is to evaluate the potential environmental benefits and drawbacks of replacing conventional mineral‐based cutting fluids with bio‐based alternatives in machining processes. The results indicate that bio‐based oil exhibits higher environmental impacts than mineral‐based oil across most impact categories, particularly global warming potential (GWP), acidification potential (AP), and smog creation potential (SCP), which can be explained by sectoral contributions identified using the Economic Input–Output Life Cycle Assessment (EIO‐LCA) approach. External normalization using US normalization factors shows that human health non‐cancer potential (HHNCP) and human health cancer potential (HHCP) are the most significant relative impact categories for both fluids. In economic terms, mineral‐based cutting fluid shows higher economic output (2.05 million USD) than bio‐based cutting fluid (1.63 million USD), mainly due to the capital‐intensive nature of petroleum refining and extraction sectors and their extensive inter‐industry linkages.Article Selection of Low Environmental Risk Processes in Plastic Waste Recovery by Comparative Life Cycle Assessment(Wiley, 2026) Kalem, Merve; Göktepeli, GamzeAbstract This study investigates the environmental impact of different valorization methods for solid and liquid products obtained from thermochemical recycling of high‐density polyethylene (HDPE) plastic waste and the mechanical recycling of these wastes. In this context, the mechanical recycling of HDPE plastic waste to produce granular raw materials (MechRecyc) and the chemical recycling of HDPE plastic waste to produce epoxy composite materials from pyrolysis chars (Pyro‐Epoxy) were discussed. Comparative life cycle analyses were conducted using SimaPro software, considering midpoint and endpoint categories for all three processes. MechRecyc performed best in terms of impact categories describing global warming, human toxicity and ecotoxicity, and fossil resource depletion. Pyro‐Fuel had the most positive impact in terms of pollutant discharges and clean water consumption. Considering all environmental impact categories, mechanical recycling had the most positive environmental impact, while both pyrolysis‐based recycling methods were found to have very similar impacts.Article Search for the Pair Production of Long-Lived Supersymmetric Partners of the Tau Lepton in Proton-Proton Collisions at S=13 TeV(Springer Science and Business Media Deutschland GmbH, 2026) Sosnov, D.; Макаренко, В.; Hayrapetyan, A.; Bergaür, T.; Benato, L.; Makarenko, V.; Tumasyan, A.; Adam, W.; Malbouisson, H. BrandaoA bstract Gauge-mediated supersymmetry-breaking models provide a strong motivation to search for a supersymmetric partner of the tau lepton (stau) with a macroscopic lifetime. Long-lived stau decays produce tau leptons that are displaced from the primary proton-proton interaction vertex, leading to an unconventional signature. This paper presents a search for the direct production of long-lived staus decaying within the CMS tracker volume in proton-proton collisions at $$ \sqrt{s}=13 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> <mml:mo>=</mml:mo> <mml:mn>13</mml:mn> </mml:math> TeV, performed for the first time with an identification algorithm based on a graph neural network dedicated to displaced tau leptons. The data sample, corresponding to an integrated luminosity of 138 fb − 1 , was recorded with the CMS experiment at the CERN LHC between 2016 and 2018. This search excludes, at 95% confidence level, stau masses, $$ {m}_{\overset{\sim }{\uptau}} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>m</mml:mi> <mml:mover> <mml:mi>τ</mml:mi> <mml:mo>~</mml:mo> </mml:mover> </mml:msub> </mml:math> , in the 126–260 (90–425) GeV range for a proper decay length of 50 mm in the maximally mixed (mass-degenerate) scenario, while for $$ {m}_{\overset{\sim }{\uptau}}=200 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>m</mml:mi> <mml:mover> <mml:mi>τ</mml:mi> <mml:mo>~</mml:mo> </mml:mover> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>200</mml:mn> </mml:math> GeV, stau proper decay lengths are excluded in the range 21–94 (6–333) mm. These results improve the exclusion limits compared to previous searches, and extend the parameter space explored in the context of supersymmetry.Article Search for Single Production of a Vector-like T Quark Decaying to a Top Quark and a Neutral Scalar Boson in the Lepton+jets Final State in Proton-Proton Collisions at $$ \sqrt{s}=13 $$ TeV(Springer Science and Business Media Deutschland GmbH, 2026) Sosnov, D.; Hayrapetyan, Aram; Andrejkovic, Janik Walter; Benato, L.; Makarenko, Vladimir; Tumasyan, A.; Adam, Wolfgang; Malbouisson, H. BrandaoA bstract A search for single production of a vector-like T quark with charge 2 e /3, decaying to a top quark and a neutral scalar boson is presented. The boson can be a standard model Higgs boson (H) or a new scalar boson (ϕ). In the first case, a branching fraction of 25% is assumed for the decay T → tH, while in the second case the T quark is assumed to decay exclusively to tϕ. The top quark is identified via its lepton+jets decay, and the neutral boson via its decay into a bottom quark-antiquark pair. Final states with Lorentz-boosted topologies are considered and machine-learning techniques are exploited for optimal event classification. The analysis uses data collected by the CMS experiment in proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb − 1 recorded at the CERN LHC in 2016–2018. Upper limits at 95% confidence level are set on the product of cross section and branching fraction for a T quark in a narrow-width approximation. They vary between 14.7 and 0.1 fb, for T quark masses in the range 1.3–3.0 TeV and ϕ boson masses in the range 25–250 GeV. These are the first exclusion limits set on the production of a single T quark decaying into a top quark and a new neutral scalar boson. For the decay channel into a top quark and a standard model Higgs boson, the results provide the best limits on production cross sections to date, for T quark masses above 2 TeV.Article Search for a New Neutral Gauge Boson Produced in Association with One or Two b Jets and Decaying into a Pair of Muons in Proton-Proton Collisions at √s=13 TeV(Springer, 2026) Hayrapetyan, A.; Andrejkovic, J. W.; Chinellato, J.; Chekhovsky, V.; Makarenko, V.; Zhokin, A.; Tumasyan, A.; Adam, W.A bstract A search for a new neutral gauge boson, Z ′ , produced in association with one or two jets, including at least one b jet, and decaying into a pair of muons is presented. The analysis uses proton-proton collision data collected with the CMS detector at $$ \sqrt{s}=13 $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msqrt> <mml:mi>s</mml:mi> </mml:msqrt> <mml:mo>=</mml:mo> <mml:mn>13</mml:mn> </mml:math> TeV, corresponding to an integrated luminosity of 138 fb − 1 . No significant deviation from background expectations is observed. Upper limits at 95% confidence level on the product of cross section, branching fraction to dimuons, acceptance, and efficiency, from 0.2 to 2 fb, are set for Z ′ boson masses between 125 and 350 GeV. Process-dependent products of acceptance and efficiency, and model-independent limits on the signal yield are provided. These are the only results to date in the 125–200 GeV mass range and the most stringent for b quark fusion production modes in the 200–350 GeV range, complementing inclusive Z ′ boson searches.Article Rock Identification with Convolutional Neural Networks: A Case Study(Czech Academy of Sciences, 2026) Karakaya, Emre; Kocer, Hasan Erdinc; Ucar, KursadArticle Performance of RIS-Aided OFDM-IM under κ-μ Fading Channels and Transceiver Hardware Impairments(Institute of Electrical and Electronics Engineers Inc., 2026) Canbilen, Ayşe Elif; Ceniklioglu, Busra; Develı, İbrahimArticle Mechanical Reliability of Scrap-Derived Al7075-Type Alloys(Springer INT Publ AG, 2026) Colak, Berat; Uludag, Muhammet; Kaya, Ozkan; Dispinar, Derya; Kocabas, MustafaRecycling of high-strength aluminum alloys has gained increasing importance due to sustainability and resource efficiency requirements. During recycling, the presence of melt-related defects may significantly affect the final product quality. In this study, the mechanical reliability of scrap-derived Al7075-type alloys was systematically investigated by correlating defect populations with mechanical performance. Scrap-derived alloys produced from Al6063 and Zamak-5 feedstocks were compared with a primary-cast alloy and a commercial wrought Al7075-T651 reference material. Mechanical behavior was evaluated using hardness, tensile strength, elongation, and impact toughness measurements through Weibull statistical analysis tools. The results reveal that mechanical reliability is strongly influenced by defect populations introduced during melt processing. While hardness showed limited sensitivity to defects, tensile strength, elongation, and impact toughness exhibited significant statistical scatter depending on melt quality. Alloys associated with lower bifilm index values generally demonstrated higher B10 reliability and larger Weibull modulus values. Fractographic observations confirmed the presence of oxide-film and bifilm-related fracture features. The findings demonstrate that recycled feedstocks can be used to produce reliable Al7075-type alloys when melt cleanliness and defect populations are properly controlled.Article Mechanical and Microstructural Properties of User-Friendly One-Part Alkali-Activated Mortars via Low-Grade Calcined Clay(Springer, 2026) Mechtcherine, Viktor; Öztürk, Oğuzhan; Liebscher, Marco; Zhao, Jitong; Köberle, Thomas; Signorini, CesareAbstract Alkali-activated materials (AAMs) have emerged as a promising alternative to traditional cement-based binders. However, their adoption is restricted by non-user-friendly production processes, the need for curing at elevated temperatures when higher amounts of aluminosilicate sources are used and the limited availability or regional dependency of precursors and activators. This study focuses on the development of one-part AAMs made with low-kaolinitic calcined clays as the main precursor (between 63–100%wt.) cured at ambient temperature. A comprehensive assessment of reaction kinetics, rheology and mechanical/microstructural properties was conducted. Results demonstrate promising fresh and hardened properties with an optimal AAM formulation including 81% of calcined clay achieving a flow diameter of 17 cm, initial/final setting times ranging from 50 to 116 minutes and 28-day compressive strength of approximately 40 MPa. Low-volume slag governs hydration kinetics and microstructure by supplying calcium-rich species and nucleation sites that activate ambient-temperature reactions and promote hybrid gel formation. It modulates setting time and refine porosity toward meso scales. Alongside an optimized solid-silicate regime, this slag-limited formulation optimizes ambient-cured fresh and hardened properties yielding a site-ready binder for multi-purpose applications. The study represents an attractive opportunity for a broader use of low-grade calcined clays as a practical and sustainable alternative to Portland-cement-based binders.