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
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.
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.
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.
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.
Istanbul Gelisim University Vocational School of Health Sciences: Monthly News Bulletin and Events (Issue: 54, June 2025)
(İstanbul Gelişim Üniversitesi / Istanbul Gelisim University, 2025) Istanbul Gelisim University Vocational School of Health Sciences
Artificial Intelligence in Operating Rooms
In today's era of rapid technological advancement, operating
rooms are undergoing significant development. Due to their
many benefits, laparoscopic surgeries, which are considered
to be minimally invasive, are being carried out more
frequently in our nation. Nevertheless, laparoscopic
procedures are currently more common than robotic surgery
devices like the Da Vinci. The major causes of this are the
high expense to hospitals and the surgeons' limited
preferences.
