DSpace Arşivi :: Ana Sayfa

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 yayınların etkisini artırmak için telif haklarına uygun olarak Açık Erişime sunar.

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Effects of Three Auditory Stimuli on Neonatal Pain During Heel Lance: A Randomized Controlled Trial
(Elsevier Ltd, 2026) Akdoğan, Bahar Nur; Mutlu, Birsen; Salihoğlu, Özgül
Background Neonatal procedural pain is frequent in intensive care settings, and effective non-pharmacological interventions are needed. Evidence comparing different auditory stimuli is limited. Objective To compare the effects of three auditory stimuli on neonatal pain during heel lance. Methods This assessor-blinded randomized controlled trial included eligible neonates born between 28 and 42 weeks of gestation who were randomly assigned to one of four groups: maternal prenatal music, white noise, heartbeat sound, or control. Results A total of 84 neonates were enrolled in the study. The enrolled neonates had a mean gestational age of 33.92 ± 3.41 weeks; 53.6% were male and 46.4% were female. During heel lance, the mean NIAPAS pain score was significantly lower in the white noise group than in the control group (8.81 ± 3.57 vs. 12.45 ± 2.45; p = 0.007). One minute after the procedure, mean pain scores were 2.48 ± 1.85 in the music group, 4.19 ± 2.53 in the heartbeat group, 3.07 ± 2.18 in the white noise group, and 7.26 ± 3.03 in the control group, with significantly lower scores in all intervention groups than in the control group (music: p < 0.001; heartbeat: p = 0.030; white noise: p = 0.011). Mean crying duration was 18.95 ± 9.11 s in the music group, 18.43 ± 11.43 s in the heartbeat group, 20.86 ± 11.49 s in the white noise group, and 27.14 ± 12.04 s in the control group. Crying duration was significantly shorter in the music (p = 0.010) and heartbeat (p = 0.025) groups than in the control group. Conclusion White noise reduced procedural pain, whereas maternal prenatal music and heartbeat sounds were effective in reducing post-procedural pain and crying. These findings suggest that simple auditory interventions may be incorporated into routine neonatal care as safe, inexpensive, and easily applicable non-pharmacological strategies for procedural pain management. Further studies are warranted to confirm these findings across different neonatal populations and clinical settings.
A Locally Validated Surrogate-Assisted Design Strategy for A Hypersonic Waverider Under Coupled Aerodynamic and Aerothermal Constraints
(Elsevier Masson s.r.l., 2026) Türkoğlu, Murat Metehan; Dönmez, Emirhan; Özkol, İbrahim
This study aims to develop and assess a physically interpretable, locally validated surrogate-assisted design strategy for a hypersonic waverider under coupled aerodynamic and aerothermal constraints. Hypersonic waverider design requires aerodynamic efficiency and preliminary aerothermal feasibility to be resolved within a coupled and physically interpretable framework. This study presents a bounded local design investigation for a hypersonic waverider at Mach 10, 30 km altitude, and α=4∘, using a physics-based evaluation chain, local design-space refinement, target-specific surrogate modeling, and post-optimization full-physics reevaluation. The local problem is defined by four geometric variables: shock angle β , width-to-length ratio W / L , leading-edge radius rle , and shaping exponent npower . The results show that β and W / L act primarily as aerodynamic performance drivers, whereas rle acts mainly as a thermal-feasibility variable with only weak influence on L / D over the examined local range. The best feasible solution is boundary-controlled rather than interior, occurring near the upper bounds of β, W / L , and npower , and near the smallest thermally admissible value of rle . Two final reference designs are retained: a peak feasible point and a recommended nominal point. The nominal design preserves nearly the same aerodynamic efficiency as the peak feasible design while increasing the thermal margin from 0.19 to 4.04 W/cm2. A local surrogate framework trained only within the trusted four-dimensional design box reproduces the optimizer-relevant structure of the problem under random hold-out, blocked hold-out, and post-opt reevaluation. Both retained reference points are shown to remain within the nominal admissible hypersonic flight corridor, while a heat-flux-bias sensitivity check indicates that the recommended nominal point has a larger screening-level thermal reserve. These results establish a physically interpretable and locally validated surrogate-assisted design strategy for hypersonic waverider development under coupled aerodynamic and aerothermal constraints.
Nanoscale Thermal Behavior and Phase Transition of Nano-Enhanced Phase Change Materials in Ribbed Channels: A Molecular Dynamics Study
(Elsevier Ltd, 2026) Li, Jialing; Gou, Xiaogui; Taner, Mahmut; Salahshour, Soheil; Emami, Nafiseh; Bayram, Mustafa
Ribbed channel geometries are widely recognized for their ability to modify flow structures and influence thermal transport. In this study, the nanoscale thermal behavior of nano-enhanced phase change materials (NePCMs) confined within a ribbed nanochannel was investigated using molecular dynamics simulations. The model consisted of a confined domain (50 × 150 × 50 Å3) with non-connected rotating ribs, and the effect of rib number (1–4) on atomic-level structural and thermal properties was systematically analyzed over a 10 ns simulation period. The results show that increasing the number of ribs altered local atomic arrangements, enhanced fluid–structure interactions, and intensified velocity fluctuations within the confined region. These effects led to measurable, statistically significant improvements in thermal transport. Specifically, heat flux increased from 5.19 ± 0.02 to 5.54 ± 0.01 W/m2 (approximately 6.7%), while thermal conductivity increased from 0.65 ± 0.01 to 0.72 ± 0.02 W/m·K (approximately 10.8%) as the rib number increased from 1 to 4. In addition, the phase transition time was slightly reduced, indicating faster energy absorption and release dynamics under enhanced mixing and interfacial interaction conditions. It should be noted that the findings provide atomistic-level insight into how internal geometric features influence heat transfer and phase transition mechanisms. These results contribute to the fundamental understanding of nanoscale transport phenomena and may inform future multiscale design strategies for advanced thermal management systems.
Investigating the Effect of Variable Electric-Field Amplitude and Frequency on the Interaction of Water/Silver Nanofluid With the SARS-Cov-2 Main Protease: A Molecular Dynamics Study
(Elsevier B.V., 2026) Alkhafaji, Ali; Zheoat, Ahmed Mohammed Attyah; Al-Dahhan, Mohammed R. Hashim; Singh, Narinderjit Singh Sawaran; Haji, Banaz Shahab; Al Garalleh, Hakim; Jastaneyah, Zuhair; Salahshour, Soheil; Taner, Mahmut
This study investigated the effect of external electric fields on the interactions between water/silver nanofluids and the SARS-CoV-2 main protease using molecular dynamics simulations. The primary objective was to evaluate how variations in electric-field strength and frequency influenced the mobility of nanofluid particles and the structural stability of viral protease at the atomic scale. Following system equilibration at physiological temperature, electric fields with amplitudes ranging from 0.1 to 0.5 V/Å and frequency parameters ranging from 0.01 to 0.04 fs⁻¹ were applied. The results demonstrate that increasing the electric-field amplitude significantly enhanced nanofluid mobility within the protease environment, as reflected by an increase in the diffusion coefficient from 75.19 to 235.25 nm²/ns and a change in the interaction energy from −312.32 to −122.80 kcal/mol. These changes indicated stronger field-induced perturbations and modified protein–nanofluid interactions. In contrast, increasing the electric-field frequency at a fixed amplitude of 0.4 V/Å decreased the diffusion coefficient from 141.19 to 68.94 nm²/ns and changed the interaction energy from −83.14 to −259.35 kcal/mol, indicating reduced atomic mobility and enhanced interaction stability. Overall, the findings reveal that higher electric-field amplitudes intensified nanofluid transport and promoted structural perturbations of SARS-CoV-2 main protease, whereas higher frequencies partially suppressed these effects. These results provide atomistic insight into the coupled influence of electric fields and nanofluids on viral protein behavior and may contribute to the development of electrically assisted nanomaterial-based antiviral technologies.
A Next-Gen Renewable Biogas-Fueled Multi-Product System; ML (ANFIS) Decision-Making and Techno-Environmental-Economic/LCA Optimization by ARO/PSO/GWO/NSGA-II Metaheuristic Algorithms
(Elsevier Ltd, 2026) Shuqi, Zhao; Limei, Yan; Khan, Mohammad Nadeem; Abd Balla, Hyder Hassan; Alanazi, Mohana; Turdialiyev, Umid; Albalawi, Hind; Fouad, Yasser; Mahariq, Ibrahim
The growing request for multi-product and sustainable energy systems has highlighted the requirement for the effective use of renewable energy sources, such as biogas, in combined power plants (CPPs). The performance and sustainability of CPPs are limited by traditional power-generation techniques, which frequently concentrate on individual outputs or disregard the integration of thermo-enviro-economic goals. This study suggests a revolutionary biogas-fueled CPP that combines open and closed air Brayton cycles with a modified Kalina cycle, serving the purpose of waste heat recovery and thermal integration, to simultaneously provide power, cool, and heat. Having modeled and analyzed the proposed trigeneration setup, backed by life cycle assessment, an Adaptive Neuro-Fuzzy Inference System was used to support system performance prediction. A multi-objective optimization (MOO) using four metaheuristic algorithms was used to obtain the optimum operating conditions, and sensitivity analysis was used to measure the effect of the design variables. The total exergy destruction for the baseline condition was 5036 kW and the total energy and exergy efficiencies were 59.86% and 36.51%, correspondingly. Economic analysis showed a 16.67-year payback period and an energy cost of 0.1796 $/kWh. While retaining high efficiency (≈38.68%), four-objective optimization decreased economic and environmental effect (TPC ≈ 68 $/GJ, COE ≈ 0.138 $/kWh, SCE ≈ 0.206 kg/kWh). The findings show the potential of the CPP as a sustainable multi-product energy solution and provide practical tips for heat recovery, turbine optimization, and biogas management in real-world scenarios.