İstanbul Gelişim Üniversitesi Kurumsal Açık Erişim Arşivi

DSpace@Gelişim, İstanbul Gelişim Üniversitesi tarafından doğrudan ve dolaylı olarak yayınlanan; kitap, makale, tez, bildiri, rapor, araştırma verisi gibi tüm akademik kaynakları uluslararası standartlarda dijital ortamda depolar, Üniversitenin akademik performansını izlemeye aracılık eder, kaynakları uzun süreli saklar ve telif haklarına uygun olarak Açık Erişime sunar.




 

Güncel Gönderiler

Öğe
The Effect of Anaerobic Fatigue on Proprioception in Adolescent Female Basketball Players
(Turkish Physiotherapy Association, 2025) Kılıç, Sefa; Alpay, Kübra; Atıcı, Emine; Soyal, Mehmet; İnal Gültekin, Güldal
Purpose: Muscle fatigue is known to alter the proprioceptive system, the central proprioception process, and power generation capacity. This study aims to determine the effect of anaerobic fatigue on lower-extremity proprioception in adolescent female basketball players. Methods: The study included licensed female basketball players (n=30) between the ages of 12 and 16. Their dominant lower extremities were evaluated for knee joint position-sense measurements. Active and passive knee joint position senses were measured with an isokinetic dynamometer at 30° and 60° degrees prior to, immediately after anaerobic fatigue, and finally after 10 minutes of the recovery period. The Wingate Anaerobic Strength Test was used to induce anaerobic fatigue. We documented the knee joint position sense of each participant. Results: Following a 30-second anaerobic fatigue, a significant reduction in the sense of active joint perception at 30° and 60° knee flexion was observed compared to baseline values (p> 0.017). The knee joint's proprioception at 30° and 60° flexion returned to baseline levels after a 10-minute recovery from fatigue. The passive joint perception did not show any statistical changes. Conclusion: Anaerobic fatigue reduces knee proprioception in adolescent female basketball players. Moreover, proprioceptive sensitivity can return to baseline levels with a recovery time of as little as 10 minutes.
Öğe
Lattice Boltzmann Modelling of Natural Convection Problems in a Cavity with a Different Wall Temperature
(Sakarya University, 2025) Aslan, Erman; Yalçın, Özlem
In this study, the cyclic natural convection problem in a square enclosure is modeled using the Lattice Boltzmann Method (LBM) under laminar flow conditions. Four different combinations of boundary conditions are employed to create cases. These cases are denoted as HHHC (Horizontal Hot Horizontal Cold), HHVC (Horizontal Hot Vertical Cold), VHHC (Vertical Hot Horizontal Cold), and VHVC (Vertical Hot Vertical Cold). Four Rayleigh numbers have been utilized to represent laminar flow conditions, namely 𝑅𝑅𝑅𝑅=104 , 105 , 106 , and 107 . For validation purposes, the wellvalidated finite volume method-based commercial code Ansys-Fluent is employed. In the VHVC model and at the highest Rayleigh number, the results obtained with LBM were compared to and validated against the results obtained with the finite volume method. Nusselt numbers are compared for the four cases based on Rayleigh numbers, and the case with highest heat transfer identified. Cases of HHHC and VHVC have produced the lowest and highest Nusselt number, respectively.
Öğe
Cation distribution and Electrical/Dielectric features of Ru substituted CoNiCuZn spinel ferrite nanoparticles
(Elsevier Ltd, 2025) Almessiere, Munirah A.; Shirsath, S. E.; Baykal, A.; Mihmanlı, Ahmet; Gondal, M. A.; Slimani, Yassine
In this study, Co0.25Ni0.25Cu0.25Zn0.25RuxFe2-xO4 (Rux→Co0.25Ni0.25Cu0.25Zn0.25Fe2-xO4) (x ≤ 0.1) nanospinel ferrite (NSFs) were manufactured via sol-gel combustion route, with varying Ru content x ≤ 0.1. The cubic spinel structure was confirmed for all products by XRD analysis. The cubic morphology of the products was confirmed via SEM (Scanning Electron Microscopy), HR-TEM (High Resolution Transmission Electron Microscopy) and TEM (Transmission Electron Microscopy) analyses. The chemical composition of the product has been confirmed by EDX (Energy Dispersive X-ray) analysis. The cation distribution was analyzed using the Bertaut method by comparing observed and calculated intensity ratios of selected X-ray diffraction reflections. The ionic radii of tetrahedral (Td) A-site and octahedral (Oh) B-site cations, theoretical lattice constants, and oxygen positional parameters were determined. Results indicate that Ru substitution leads to a slight expansion in the B-site ionic radius and a subtle increase in the lattice constant, while the A-site configuration remains unaffected. The oxygen positional parameter showed minimal change, indicating structural stability. Additionally, dielectric properties were examined, revealing that the dielectric constant increases with Ru content and T, following MaxwellWagner interfacial polarization. AC conductivity analysis indicated thermally activated hopping mechanisms with enhanced polaron hopping due to Ru substitution. Dielectric measurements showed that the dielectric constant increased with Ru content, reaching a maximum of 150,000 at low frequencies for x = 0.10. AC conductivity analysis demonstrated thermally activated hopping mechanisms, with conductivity values increasing from 0.3 S/m for x = 0.00–1.2 S/m for x = 0.10 at 120 ◦C. This study presents insights into the structural and electrical features of Rux→Co0.25Ni0.25Cu0.25Zn0.25Fe2-xO4 (x ≤ 0.1) NSFs, which could be valuable for magnetooptical applications.
Öğe
Energy intensive growth and the transition pathways: Insights into the role of renewable energy and open market conditions in developing countries
(Elsevier Ltd, 2025) Bekun, Festus Victor; Fumey, Michael Provide; Staniewski, Marcin W.; Sun, Lipeng; Agboola, Philips O.
This study examines the impact of economic growth, renewable energy consumption, and open market conditions on energy intensity across 34 developing countries from 1999 to 2022 using the method of moments quantile regression. By analysing how these factors influence energy intensity across different quantiles, the study provides insights into the heterogeneous nature of these relationships. The results reveal a positive and statistically significant impact of economic growth per capita on energy intensity across all quantiles, with a more substantial effect at higher energy intensity levels. However, the squared term of economic growth per capita exhibits a negative and significant influence, confirming the presence of an inverted U-shaped relationship. Renewable energy consumption reduces energy intensity significantly across all quantiles, with more potent effects at higher quantiles. This indicates that economies with higher energy intensity benefit more from transitioning to renewable energy sources. Market freedom initially contributes to higher energy intensity. However, its impact diminishes at higher quantiles, suggesting that while economic liberalisation may increase energy consumption in the short run, it can promote efficiency improvements over time. These findings highlight the need for differentiated policy approaches, where economies with lower energy intensity focus on balanced growth strategies. In comparison, those with higher energy intensity prioritise aggressive renewable energy integration and efficiency-enhancing policies. The study underscores the importance of adopting tailored energy policies that consider the varying impacts of economic and policy variables across different energy intensity levels to achieve sustainable energy transitions.
Öğe
Tunned the structure and magnetic characteristics of noble metal (Pd)-doped Ba-Sr nanohexaferrites
(Elsevier B. V., 2025) Algarou, N. A.; Aldakheel, R. K.; Almessiere, M. A.; Baykal, Abdülhadi; Güngüneş, H.; Çalışkan, S.; Mihmanlı, Ahmet
In this study, various ratios of Pd-doped Ba-Sr nanohexaferrites (NHFs) were studied. All samples were produced via sol–gel combustion and were designated as Ba0.5Sr0.5Pd3xFe12-2xO19 (x ≤ 0.1) NHFs. Detailed examinations of the magnetic and structural features were conducted. X-ray diffraction (XRD) confirmed the presence of a M-type HF phase, along with a small phase of iron oxide (Fe2O3) for some doping ratios. Both the SEM and TEM (Scanning and Transmission electron microscope respectively) revealed the formation of the hexagonal platelet morphology. The hyperfine parameters were determined by using Mossbauer ¨ spectroscopy. Pd2+ ions substituted Fe3+ ions at 12k site. The crystal symmetry not influenced by substitution. Fe3+ charge state was detected all samples. Magnetic properties are investigated through hysteresis loop analysis at room temperature (RT) and 10 K. Ms (saturation magnetization), Mr (remanence), Hc (coercivity), SQR (squareness ratio), and nB (experimental magnetic moment), were evaluated as a function of Pd doping. The pristine sample exhibited hard ferrimagnetic behavior with high Hc and Mr, while Pd-doped samples demonstrated reduced magnetic properties. Particularly, intermediate Pd concentrations (x = 0.04 and 0.06) resulted in slight increases in Ms. SQR values signify multidomain and single-domain nature for Pd-doped and undoped samples, respectively. XPS’ (X-ray photoelectron spectroscopy) broad spectrum of energies verified the presence of Ba, Sr, Pd, Fe, and O in the product.