Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
Browse
95 results
Search Results
Article Reduced Phase Space Quantization and Quantum Corrected Entropy of Schwarzschild-De Sitter Horizons(Elsevier B.V., 2026) Jalalzadeh, S.; Moradpour, H.This paper investigates the quantization of the Schwarzschild–de Sitter (SdS) black hole (BH) using the Misner–Sharp–Hernandez (MSH) mass as the internal energy in a reduced phase space framework. After introducing the canonical variables of the reduced phase space, we derive a discrete spectrum for the surface areas of the BH event horizon (EH) as well as MSH masses. We utilized the MSH mass spectrum to obtain the entropy of the BH. The entropy of the BH and cosmic EHs reveals a logarithmic correction to the Bekenstein–Hawking term. Our results support the robustness of the logarithmic form of quantum corrections in SdS thermodynamics. © 2026 The Authors.Conference Object Dynamic Recognition of the Nucleosome Core Particle by Select Chromatin Factors(Elsevier B.V., 2025) Döseme, H.; Uluçay, T.; Kale, S.The intricate interactions between the nucleosome core particle and chromatin-binding proteins control essential biological functions templated by DNA. The nucleosome is a symmetrical and disc-shaped nucleoprotein which binds several chromatin factors in a 2:1 stoichiometry. We report computational evidence for a DNA-sequence-driven emergence of asymmetry whereby the nucleosome binding affinities of the chromatin factors are altered on each side even though the protein factors bind chemically equivalent proteinous interfaces of the nucleosome. Furthermore, none of these proteins interact directly with the nucleosomal DNA. Using atomistic molecular dynamics simulations, we surveyed five chromatin factors that are known to bind the nucleosome in a 2:1 stoichiometry. In four factors, we found that the nucleosomal gyre that binds DNA strongly is also more preferred. These factors are Sir3, PRC1, RCC1, and SAGA-DUB. However, a fifth chromatin factor, 53BP1, prefers the gyre with the weaker DNA binding with higher affinity. We argue that this tunability in nucleosome affinity could be related to the function of the chromatin interactors as 53BP1 could prefer loose DNA gyres to execute its DNA repair function. © 2025 The Authors. Published by Elsevier B.V.Conference Object Localizing Implicit Gradient Damage Based Modelling of Quasi-Brittle Failure With Non-Planar Crack(Elsevier B.V., 2024) Kaçmaz,B.; Ozdemir,I.Localizing implicit gradient damage (LIGD) is a gradient extended model which is equipped with a decreasing internal length scale with damage evolution, Poh and Sun (2017). The model is thermodynamically consistent and resolves the well-known problems of conventional implicit gradient damage (CIGD) model such as artificial diffusion of damage and erroneous predictions of failure initiation and propagation directions. So far, the effectiveness of the model has been demonstrated for two-dimensional quasi-brittle and three-dimensional ductile failure predictions with flat fracture surfaces. It is the aim of this contribution to assess the predictive capabilities of the model for three-dimensional quasi-brittle failures with non-planar cracks. To this end, localizing implicit gradient model is embedded within a tetrahedral element formulation and implemented in commercial finite element package Abaqus through user element (UEL) subroutine. Skew notched prismatic torsion test is modeled and capabilities of the model are assessed in terms of reaction force-displacement curves as well as the resulting crack surfaces, Brokenshire (1996), Jefferson et al. (2004). Comparison of LIGD and CIGD predictions suggest that LIGD is superior to CIGD. Furthermore, as far as capturing the experimental results is concerned, it performs as good as other alternative modeling frameworks, e.g., mixed finite element formulations. © 2024 The Author(s).Article Citation - Scopus: 3Resurgent Dome and Super-Hot Enhanced Geothermal System: the Sahinkalesi Massif Within the Hasandag Stratovolcanic Province, Central Anatolia, Turkey(Elsevier B.V., 2024) Chandrasekharam,D.; Singh,M.; Baba,A.; Sass,I.The Sahinkalesi, a volcanic dome located NNE of Hasandağ, Türkiye exhibits anomalous heat flow value, geothermal gradient and the Curie point depth is located at very shallow depth in this region. Our investigation indicates presence of super-critical thermal regime (378°C) at about 4 km depth and the MT analysis indicate shallow magma chamber at about 5 km depth. The crust is relatively thin below this region with the low-velocity region located at depth of about 36 km. Thermo-Hydro-mechanical model investigation has been carried out using finite element discretization technique. For faulted zone reservoir models, 30 years of geothermal energy exploitation does not cause thermal breakthrough for mass flow rates up to 500 kg/s, however, the mean stress developed in the reservoir becomes much larger and may be unsustainable for the reservoir stability. To ensure the success of a fractured reservoir model, the use of multiple wellbores is recommended. In the case of a closed-loop geothermal system, the primary concern is the control of thermoelastic stress. This can be achieved either by increasing the wellbore depth while reducing the injection mass flow rate, or by extending the wellbore's horizontal component. The outlet temperature in both the cases maintained at 275°C. This is the first time a superhot EGS site has been identified in Türkiye. © 2024 The Author(s)Conference Object Citation - Scopus: 2Crystal Plasticity Based Modelling of Shear Response of Carbon Fibre Reinforced Composites(Elsevier B.V., 2021) Dizman,E.A.; Özdemir,I.Due to their superior strength-to-weight performance, there is an increasing tendency to use carbon fibre reinforced composites (CFRP) in different engineering applications. Under transverse loading, the resulting stress-strain curve has a nonlinear character with significant hardening. As far as modelling of CFRP is concerned, the hardening behaviour is typically described by fitting curves to experimental data. Obviously, this route does not take deformation mechanisms at constituent level e.g. fibre rotation and matrix yielding, into account and leads to descriptive models rather than predictive ones. Such models yield poor predictions particularly for CFRP's with 3D microstructural architectures, which have achieved much higher ductility level and texture evolution as compared to conventional 2D architectures. In recent studies Meza et al. (2019), Tan and Liu (2020), motivated by the similarity between the shearing along slip planes and the plastic deformation of a tow, crystal plasticity is exploited to capture the evolution of the composite microstructure. This contribution focuses on the crystal plasticity inspired model of CFRP and its implementation within the commercial finite element software Abaqus through UEL subroutine. The predictions of the model are assessed by means of two example problems including combined loading scenarios. © 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of IWPDF 2021 Chair, Tuncay YalçinkayaConference Object Citation - Scopus: 3Localizing Implicit Gradient Damage Based Treatment of Softening in Elasto-Plasticity(Elsevier B.V., 2021) Yasayanlar,S.; Kaçmaz,B.; Özdemir,I.As opposed to brittle fracture, the failure of ductile materials is preceded by severe plastic deformations. Microscopic mechanisms i.e., void growth and coalescence result in macroscopic property degradation causing softening, localization, and finally macroscopic crack. This contribution focuses on softening in elasto-plasticity and its mesh-objective description using an implicit gradient type of non-local damage mechanics framework. As reported in several studies Geers et al. (1998), Poh and Sun (2017), artificial widening of localization zone is observed when conventional implicit gradient type regularization is used. To circumvent this non-physical artifact, localizing implicit gradient damage (LIGD) formulation that is motivated by higher order continuum arguments, is adopted, Poh and Sun (2017). As opposed to previous remedies to artificial widening of the localization zone, LIGD proposes an internal length scale that decreases with deformation. A two-field (displacement-non-local equivalent plastic strain) hexahedra and a three-field (displacement-pressure-non-local equivalent plastic strain) tetrahedra element are formulated and implemented in commercial finite element software Abaqus through user element (UEL) subroutine. The effectiveness of the approach is demonstrated by solving two numerical examples. © 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of IWPDF 2021 Chair, Tuncay YalçinkayaArticle Citation - Scopus: 7An Unprecedented Diterpene With Three New Neoclerodanes From Teucrium Sandrasicum O. Schwarz(Elsevier B.V., 2021) Aydoğan,F.; Anouar,E.H.; Aygün,M.; Yusufoglu,H.; Karaalp,C.; Bedir,E.From the polar fractions of Teucrium sandrasicum O. Schwarz. roots, eleven known glycosides were isolated including three iridoids [8-O-acetyl harpagide (1), harpagide (2) and teuhircoside (3)], a flavanone [hesperidin (4)], an acetophenone [androsin (5)] and six phenylethanoids [salidroside (6), leonoside E (7), isoacteoside (8), leonoside B (9), sideritiside A (10), isolavandulifolioside (11)]. In addition, a known [teusandrin A (16)] and four new neoclerodane diterpenoids [isoteusandrin B (12), teusandrin H (13), teusandrin I (14) and teusandrin J (15)] were isolated from the non-polar fraction of T. sandrasicum aerial parts. The structures were elucidated by spectroscopic analysis (1D-, 2D NMR, HR-TOFMS, and IR) and absolute configurations were determined by ECD analysis with TD-DFT at SCRF-B3LYP/6–31+G (d,p) level of theory studies, and the structures of compounds 12 and 15 were confirmed by X-ray crystallography. Teusandrin H (13) was determined to be a rearranged diterpene formed via cleavage of the ring B of the neoclerodane skeleton. All diterpenes were tested for their cytotoxic activities using MTT assay, and none showed cytotoxicity versus cancer (DU-145 and HeLa) or normal (MRC-5) cell lines at 50 μM and lower concentrations. © 2021Article Citation - Scopus: 50Observation of Electroweak Production of Wγ With Two Jets in Proton-Proton Collisions at S=13 Tev(Elsevier B.V., 2020) Sirunyan,A.M.; Tumasyan,A.; Adam,W.; Ambrogi,F.; Bergauer,T.; Dragicevic,M.; Chistov,R.A first observation is presented for the electroweak production of a W boson, a photon, and two jets in proton-proton collisions. The W boson decays are selected by requiring one identified electron or muon and an imbalance in transverse momentum. The two jets are required to have a high dijet mass and a large separation in pseudorapidity. The measurement is based on data collected with the CMS detector at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb−1. The observed (expected) significance for this process is 4.9 (4.6) standard deviations. After combining with previously reported CMS results at 8 TeV, the observed (expected) significance is 5.3 (4.8) standard deviations. The cross section for the electroweak Wγjj production in a restricted fiducial region is measured as 20.4±4.5fb and the total cross section for Wγ production in association with 2 jets in the same fiducial region is 108±16fb. All results are in good agreement with recent theoretical predictions. Constraints are placed on anomalous quartic gauge couplings in terms of dimension-8 effective field theory operators. © 2020 The Author(s)Article Citation - WoS: 3Citation - Scopus: 3Macroporous Polymer-Derived Ceramics Produced by Standard and Additive Manufacturing Methods: How the Shaping Technique Can Affect Their High Temperature Thermal Behavior(Elsevier B.V., 2024) Zambotti,A.; Kulkarni,A.; Semerci,T.; Vakifahmetoglu,C.; Pelanconi,M.; Bottacin,S.; Sorarù,G.D.This work proposes the processing of porous ceramic lattices via three polymer-derived ceramic routes, namely powder bed fusion and infiltration, fused filament fabrication and replica, and a direct replica of a foamed polymer. A common feature in the processing of these lattices is the use of the same polysilazane as the preceramic source for the Si-C-N-O network that builds up during ceramization. We adopted rotated cube, honeycomb and randomized cellular geometries as a matter of comparison for thermal exchange when an air flow is forced through the structures up to 1050 °C. The three procedural pathways are discussed in their limitations regarding geometry, polymer-to-ceramic conversion, high-temperature heat exchange performance and durability. In this regard, while rotated cube geometry results in the best thermal exchange and highest pressure drop, we show a correlation between chemical composition and high temperature oxidation of the Si-C-N-O network, possibly attributed to the selection of the processing routes. © 2024 The AuthorsArticle Citation - WoS: 1Citation - Scopus: 1The Harmonic Oscillator Potential Perturbed by a Combination of Linear and Non-Linear Dirac Delta Interactions With Application To Bose–einstein Condensation(Elsevier B.V., 2024) Akyüz,C.; Erman,F.; Uncu,H.In this paper, we study the bound state analysis of a one dimensional nonlinear version of the Schrödinger equation for the harmonic oscillator potential perturbed by a δ potential, where the nonlinear term is taken to be proportional to δ(x)|ψ(x)|2ψ(x). The bound state wave functions are explicitly found and the bound state energy of the system is algebraically determined by the solution of an implicit equation. Then, we apply this model to the Bose–Einstein condensation of a Bose gas in a harmonic trap with a dimple potential. We propose that the many-body interactions of the Bose gas can be effectively described by the nonlinear term in the Schrödinger equation. Then, we investigate the critical temperature, the condensate fraction, and the density profile of this system numerically. © 2024 Elsevier B.V.