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ArticleYalnız künye2026/r/ebyu/10635
Coupled Neutronic and Thermal-Hydraulic Analysis of Inner Moderator Radius Effects in Dual-Cooled Annular UO2 and Thorium-Based Fuels for a LW-SMR
Kabach, Ouadie; Rifai, Hanan; Uzun, Sinem; Genç, Yasin; Amsil, Hamid; El Banni, Fadi; Uzun, Bedrettin; Chakir, El Mahjoub
This study evaluated the effect of the inner moderator radius on the neutronic and thermal-hydraulic performance of dual-cooled annular UO2 and (Th-233U-235U)O2 fuels for a light water (LW) small modular reactor (SMR) derived from the AP300™ concept. The analysis combined lattice neutronic calculations and fuel channel thermal-hydraulic modeling to assess reactivity behavior, discharge burnup, cycle length, isotopic evolution, power peaking factor, pressure drop, coolant temperature rise, and departure from nucleate boiling ratio (DNBR). The results showed that the thorium-based fuel provided better fuel utilization than UO2 over the entire investigated range of inner moderator radii. Under single-batch operation, the discharge burnup of the thorium-based fuel reached 36.96 to 38.57 gigawatt-days per metric tonne (GWd/t), whereas the UO2 cases achieved 27.14 to 35.41 GWd/t. For a three-batch strategy, the thorium-based option attained 166.3 to 170.8 GWd/t and yielded longer operating cycles. It also significantly suppressed plutonium production and higher actinide accumulations, while reducing 135Xe and 149Sm poisoning. Increasing the inner moderator radius improved fertile-to-fissile conversion in both fuel systems; however, the thorium-based fuel exhibited much smaller performance degradation across the examined range. From the thermal-hydraulic standpoint, all the cases exhibited very similar behavior, with low power peaking factors, DNBRs near 2.3, and nearly unchanged pressure drop trends. Overall, the results demonstrated that thorium-based dual-cooled annular fuel is a promising option for improving fuel cycle performance while maintaining favorable thermal-hydraulic safety margins in LW SMRs.
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ArticleYalnız künye2026/r/ebyu/10593
Experimental and numerical thermo-hydraulic performance optimization of fin and tube heat exchanger using genetic algorithms
Tepe, Ahmet Ümit; Kuru, Muhammet Nasıf; Yilmaz, Harun
This study focuses on the multi-objective optimization of fin and tube heat exchangers to maximize the Thermal Performance Factor and minimize the Volume . A novel fin design is proposed and integrated onto the tube surfaces to enhance thermo-hydraulic performance. The numerical simulations were conducted using Computational Fluid Dynamics with the conjugate heat transfer method, while the optimization framework was established on modeFRONTIER using a Multi-Objective Genetic Algorithm (MOGA-II). The numerical model was validated against experimental data in this study and existing literature data. The optimization process investigated various fin parameters, (Dwing, Dring, αback,αfront and Gwing), alongside heat exchanger design parameters (ST and SL) and inlet velocity (Vinlet) including 0.3–10 m/s. A total of 1271 design points were evaluated, resulting in 998 feasible configurations and 24 distinct Pareto-optimal designs. The Pareto-optimal Design set yielded TPF values ranging from 1.09 to 1.66. The results highlight the typical trade-off between thermal performance and heat exchanger Volume . Higher TPF values generally correspond to larger volumes, with Design ID 1 achieving the maximum TPF (1.66) but also the largest volume. Conversely, designs with smaller volumes (Design IDs 22–24) exhibit lower TPF values (≈1.09–1.13). Even among designs with the same volume and inlet velocity, variations in fin geometry significantly affect thermal performance. Therefore, designs with higher TPF are preferable when thermal efficiency is the priority, while more compact designs are suitable when minimizing volume is the main goal.
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ArticleYalnız künye2026/r/ebyu/10591
Development and analysis of machine learning-based hybrid optimization framework for cutting temperature-based energy consumption estimation in turning of titanium alloys
Akdulum, Aslan; Siyambaş, Yusuf; Çakıroğlu, Ramazan; Uzun, Gültekin
This study develops a machine learning-based hybrid optimization framework to predict energy consumption from cutting temperature in turning of Ti6Al4V alloy under different cooling environments. Due to the poor thermal conductivity of titanium alloys, heat accumulation in the cutting zone increases energy consumption and reduces process efficiency. Cutting temperatures were recorded in real time using a thermal camera, and energy consumption was measured with a power analyzer. Statistical features extracted from temperature data served as inputs for energy prediction. A hybrid optimization framework was developed by integrating feature selection methods, machine learning algorithms, and hyperparameter optimizers. Among six algorithms evaluated, CatBoost combined with SHAP-based feature selection and Optuna hyperparameter optimization achieved the best performance. The proposed hybrid model (CAT+SHAP+Optuna) provides a 91% improvement in Mean Squared Error compared to the benchmark model, demonstrating high accuracy in energy consumption estimation. This approach offers significant potential for enhancing energy efficiency and promoting sustainable manufacturing in the machining of difficult-to-cut materials.
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ArticleYalnız künye2026/r/ebyu/10506
2D/2D Borophene/Ti2NbC2Tx MXene hybrids as advanced electrodes for supercapacitors
Yesilbag, Yasar Ozkan; Tuzluca Yesilbag, Fatma Nur; Huseyin, Ahmad; Salih, Ahmed Jalal Salih; Ertugrul, Mehmet
Two-dimensional (2D) hybrid electrodes combining complementary charge-storage mechanisms represent a promising approach for advanced supercapacitors. In this work, few-layer β-borophene nanosheets were synthesised via a modified Hummers' method and integrated with Ti2NbC2Tx MXene to form 2D/2D hybrid electrodes. Structural characterization confirmed successful borophene exfoliation, MXene–borophene heterostructure formation with locally ordered domains and enhanced ion accessibility. Electrochemical measurements demonstrated that hybrid electrodes significantly outperformed pristine MXene and borophene. The MX-B10 composition exhibited the highest specific capacitance, superior rate capability, and optimal charge-transfer kinetics attributed to synergistic surface-controlled capacitance from borophene and diffusion-assisted ion transport in MXene. A symmetric solid-state supercapacitor (SSSC) assembled with MX-B10 electrodes achieved 54 Wh kg−1 at ~300 W kg−1, retaining 23.2 Wh kg−1 at ~7.6 kW kg−1 with ~97% capacitance retention after extended cycling, These results highlight the potential of borophene–MXene heterostructures for high-performance energy storage applications.
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ArticleYalnız künye2026/r/ebyu/10487
Application of a heat spreader plate and metal foam for battery thermal management in different cases
Demir, Fatih
Effective temperature management is crucial to ensuring the safety, performance, and lifespan of lithium-ion batteries, especially as electric vehicles become more prevalent globally as part of sustainable transport efforts. Significant temperature increases during cycling may reduce efficiency, promote irregular aging, and raise safety concerns. This study aims to improve heat transfer for batteries operating under natural convection at reliable operating temperatures, without requiring maintenance or additional costs at high discharge rates of 7C to 10C. First, the numerical models of the lithium-ion battery and the metal foam are validated through experimental studies. After that, an innovative approach is presented that uses a heat spreader plate and heat spreader metal foam, either separately or in a hybrid, for battery thermal management. It investigates the effect of heat spreader plate thickness (0.5–2 mm), heat spreader metal foam thickness (0.5–2 mm), porosity (5–40), pore per inch (0.899–0.958), hybrid structures (1 to 8 cases), and different coolants (air, mineral oil, synthetic, and natural esters) on battery thermal management. The thermocouple measurements and infrared camera images are evaluated in the experimental study. At the same time, the battery surface temperatures, temperature homogeneity, temperature contours, and velocity vectors are discussed in the numerical model. The results show that increasing the thickness of the heat spreader plate from 0.5 to 2 mm leads to 17.5% and 16% decreases in maximum temperatures at 7C and 10C discharge rates, respectively, at 100% discharge depth. The battery temperatures depend on the varying thicknesses rather than the changing positions of the heat spreader plate and heat spreader metal foam that form the hybrid structures. On the battery surface with a heat spreader plate and with a heat spreader foam, mineral oil reduces the maximum battery surface temperature by factors of 1.6 and 1.92, respectively, compared to air. Increasing the pore per inch at a given ε reduces temperature homogeneity on the battery surface.
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ArticleAçık Erişim2026/r/ebyu/10418
Fighting against energy consumption risk by diversifying energy sources
Kuziboev, Bekhzod; Radulescu, Magdalena; Çatık, A. Nazif; Makhmudov, Samariddin; Balli, Esra; Allayarov, Sardor
Currently economic turbulence and geopolitical fluctuations are causing high prices and supply disruptions in energy markets. As a result, energy consumption risks are becoming more severe. Diversifying energy sources is one way to address these challenges. This study examines how energy source diversification influences energy consumption risk in 36 developed countries from 2000 to 2018, using Method of Moments Quantile Regression (MMQR) and Panel Threshold Regression (PTR) Models. The MMQR captures heterogeneous effects across various levels of energy consumption risk, offering insights into how diversification strategies differ in effectiveness across the risk distribution. The PTR Model identifies potential nonlinear relationships and regime-dependent effects based on economic development levels, enabling an analysis of how the diversification-risk relationship changes across different stages of economic advancement. These methods are well-suited for the non-normal distribution of variables and the potential structural breaks in the relationship between energy diversification and consumption risk. The findings align with theory, revealing that the effects of energy source diversification on energy consumption risk are negative across all quantiles, from 10 % to 90 %. Furthermore, PTR results reveal that energy source diversification reduces energy consumption risk in both the lower and upper regimes of economic development. The study's results provide valuable guidelines for policymakers.
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ArticleAçık Erişim2026/r/ebyu/10414
Model-Based Exergy and Partial Techno-Economic Screening of Hydrogen, Ammonia, E-Diesel, and Waste Cooking Oil Biodiesel Pathways for Heavy-Duty Internal Combustion Engines
Demirci, Oğuz Kürşat
Five pathways—diesel, renewable hydrogen, green ammonia, Fischer–Tropsch e-diesel, and B100 waste cooking oil fatty acid methyl ester (WCO-FAME)—were compared on a common service basis using a reduced-order engine exergy model, a partial techno-economic cost model, and 10,000 Latin hypercube simulation samples; each alternative was paired with diesel by sample index. The results were normalised to 1 kWh of net brake work (kWhb) and 1000 tonne-kilometres of freight work (1000 tkm). A carbon balance back-calculation from European Commission Vehicle Energy Consumption Calculation Tool (VECTO) monitoring data for subgroup 5-Long Haul (5-LH; a 4 × 2 tractor–semitrailer) yielded 89.31 kWhb/1000 tkm; first-order payload penalties increased this requirement to 94.79 kWhb/1000 tkm for hydrogen and 91.97 kWhb/1000 tkm for ammonia. Deterministic central-case exergy efficiencies were 43.02% for hydrogen, 39.67% for e-diesel, 39.35% for diesel, 37.56% for B100, and 33.81% for ammonia. The study-specific partial cost was expressed in 2025 EUR per 1000 tkm and included delivered fuel, maintenance, and annualised incremental vehicle capital; common fleet costs, including driver, tyre, toll, insurance, and tax costs, and externalities were excluded. Therefore, this metric was not a full freight cost or tariff. Deterministic central-case costs were EUR 25.85/1000 tkm for diesel, EUR 26.72/1000 tkm for B100, EUR 58.64/1000 tkm for hydrogen, EUR 59.84/1000 tkm for ammonia, and EUR 67.44/1000 tkm for e-diesel. Hydrogen exceeded diesel in exergy efficiency in 96.50% of the paired simulation samples; all three electrofuel pathways were costlier than diesel in every paired simulation sample, whereas B100 was cheaper than diesel in 35.62% of the paired simulation samples. Thus, hydrogen led in exergy efficiency, diesel in cost under the defined partial economic boundary, and B100 was the closest cost competitor. These are conditional model-screening results rather than a completed comparative life-cycle assessment: no quantitative life-cycle impact assessment (LCIA), environmental ranking or marginal abatement cost result is reported.
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ArticleAçık Erişim2026/r/ebyu/10404
Nonlinear effects of financial development on energy infrastructure: Insights from nonlinear panel models
Helmi, Mohamad Husam; Balli, Esra; Çatik, Abdurrahman Nazif; Kuziboev, Bekhzod; Ruzmetova, Maxbuba; Makhmudov, Samariddin
This study examines the impact of financial development on energy infrastructure needs in a sample of 85 countries over the period 2000–2023. The analysis combines linear panel estimators with advanced nonlinear methods, including Method of Moments Quantile Regression (MMQR), the Instrumental-Variable Partially Linear Functional-Coefficient model (IVPLFC), and the dose–response function. These methods allow us to examine heterogeneity, dynamic persistence, and nonlinear marginal effects. A key contribution of the study is the use of the Energy Infrastructure Needs index, which captures deficiencies across electricity generation, transmission, distribution, and storage, rather than relying on narrower traditional proxies. The results show that stronger financial development significantly reduces energy infrastructure needs. This effect is strongest at earlier stages of financial development, while diminishing marginal effects emerge as financial systems mature. The MMQR results reveal distributional differences across levels of energy infrastructure needs, while the IVPLFC and dose–response results confirm clear nonlinear effects. Overall, the findings show that financial development plays an important but uneven role in reducing energy infrastructure needs. Financially underdeveloped economies benefit most from expanding access to credit, strengthening banking intermediation, and improving liquidity, whereas more financially developed economies require complementary institutional and regulatory reforms to achieve further progress.
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ArticleYalnız künye2026/r/ebyu/10388
Adaptive radiation- and plasma-resilient power electronics for deep-space applications
Can, Erol
Space missions expose spacecraft electronics to complex space environments, including charged particle fluxes, solar wind plasma, and high-energy radiation, which can induce surface charging, electrostatic discharges (ESD), and single-event upsets (SEUs) in power conversion systems. Traditional mitigation strategies, such as radiation-hardened components and shielding, offer partial protection but incur significant mass and efficiency penalties and do not address transient plasma-induced disturbances. This study presents a physics-informed, plasma-resilient design methodology for DC–DC converters in deep-space applications. A comprehensive space-environment simulation framework is developed to model heliocentric plasma density, solar wind velocity, proton energy spectra, and surface charging, incorporating both low- and high-frequency fluctuations. Building on this, a radiation-aware, adaptive DC–DC converter topology is proposed, coupled with a model reference adaptive control (MRAC) architecture and disturbance observer, enabling real-time mitigation of plasma-induced voltage fluctuations, SEU step events, and input ripple. Simulation results demonstrate that the proposed approach maintains the output voltage close to the nominal value under the considered space-environment disturbances. The adaptive controller reduces the RMS voltage error from approximately 10.3–12.6 V in the uncontrolled system to approximately 1.86–1.91 V across the investigated operating scenarios while significantly suppressing transient deviations caused by plasma fluctuations and SEU events. Frequency-domain analysis confirms effective attenuation of low-frequency plasma-induced transients, while Lyapunov-based stability proofs ensure guaranteed closed-loop robustness. The integrated methodology enables reliable, efficient, and adaptive energy management for long-duration space missions, highlighting the importance of environment-aware hardware-control co-design for future deep-space spacecraft.
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ArticleYalnız künye2026/r/ebyu/10385
Data-driven forecasting of photovoltaic performance with explainable artificial intelligence: Experimental validation using environmental and thermal predictors
Karakoyun, Yakup; Katipoğlu, Okan Mert; Dogan, Ahmet; Canbaz, Ali
PV systems meet energy demand, but environmental and operational factors affect their performance. This study used a three-scenario ablation framework to predict PV power from baseline meteorological and operational variables to under-panel temperature and finally to the full thermal configuration, including water temperature (a newly studied variable). Scenario 1 included time, air temperature, panel angle, relative humidity, and average wind speed; Scenario 2 added under-panel temperature; and Scenario 3 added water temperature. Direct thermal predictors were evaluated separately from meteorological inputs using this design. Four sophisticated ML algorithms, Random Forest (RF), CatBoost, Support Vector Machine (SVM), and one-dimensional Convolutional Neural Network (1D CNN), were refined by Randomized Search (RS) and evaluated using metrics. According to the first group of power prediction results under the full Scenario 3 configuration, the CatBoost-RS model demonstrated superior performance with RMSE = 10.61, MAE = 8.41, AIC = 222.22, KGE = 0.957, and R2 = 0.99. For the second group, the SVM-RS model outperformed others, achieving RMSE = 8.02, MAE = 5.50, AIC = 200.36, KGE = 0.994, and R2 = 0.992. Comparative analysis showed that CatBoost-RS was the most robust predictor, while RF exhibited proficiency in managing nonlinearity in this experimental setting. One-way ANOVA, paired t -test, Wilcoxon signed-rank test, bootstrap confidence intervals, and effect size (Cohen’s d) analyses across both groups show that optimised ensemble and kernel-based models outperform the convolutional approach in predictive performance. Experimental validation and high predictive accuracy improve PV performance prediction in the proposed method.
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ArticleAçık Erişim2026/r/ebyu/10258
Revealing the effectiveness of hydropower innovations on emission level in Japan: evidence from machine-learning algorithm
Özkan, O.; Destek, M.A.; Khan, Z.; Manga, M.
This study explores how oil efficiency and hydropower innovation affect carbon emissions in Japan. In this direction, the novel multivariate quantile on quantile regression technique is applied to explore the period from 2000 to 2020. In addition, to prevent omitted variable bias, the environmental implications of industrialization, urbanization, and economic growth are also observed. The empirical findings indicate that oil efficiency, industrialization, and hydropower innovations are all lower carbon emissions. However, urbanization and economic growth harm the environmental quality. Lastly, a robustness check is performed using a kernel-based regularized least squares technique based on machine learning. The results of this investigation support the claim that oil efficiency and hydropower innovation can reduce emissions. Furthermore, it is found that the emission-reducing impact of both gets stronger as the emission level rises.
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ArticleAçık Erişim2026/r/ebyu/10242
Energy, exergy and exergoeconomic analysis of a CI engine fuelled with waste frying oil biodiesel blended with waste tyre pyrolysis oil and higher alcohols (Heptanol and Octanol): A waste-to-energy approach
Gülcan, Halil Erdi; Demirci, Oğuz Kürşat; Erol, Derviş; Tunçer, Erdal
This study evaluates a waste-to-energy diesel concept that co-valorises waste cooking oil and end-of-life tyres by formulating biodiesel–tyre pyrolysis oil blends with small additions of higher alcohols (1-heptanol and n-octanol). Five fuels (B100, B90T10, B85T10H5, B85T10O5 and B80T10H5O5) were tested in a single-cylinder diesel engine. Engine performance, emissions and combined energy–exergy–exergoeconomic indicators were used to assess thermodynamic and economic viability. The quaternary blend B80T10H5O5 achieved the highest mean energy and exergy efficiencies (26.5 % and 24.6 %) and reduced brake-specific fuel consumption by about 5 % relative to neat biodiesel, owing to improved volatility and fuel oxygenation. This benefit was accompanied by higher NOx emissions and the largest specific exergy cost (≈1430 USD GJ−1) at full load. By contrast, the binary blend B90T10 preserved biodiesel-like efficiency while lowering the specific exergy cost of shaft power by roughly 10 %, emerging as the most cost-effective option. Overall, modest shares of tyre pyrolysis oil (10 %) and long-chain alcohols (≤5 %) in waste-oil biodiesel can provide an attractive compromise between energy efficiency, emissions and exergy-based cost, supporting circular-economy-oriented diesel combustion.
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ArticleYalnız künye2026/r/ebyu/10214
Experimental assessment of fanless thermoelectric cooling using a folded aluminum plate under natural convection
Ozer, Rahim Aytug; Doğuş Tuncer, Azim; Khanlari, Ataollah; Sözen, Adnan; Kılınç, Cuma; Afshari, Faraz
This study experimentally investigates the performance of a fanless thermoelectric cooling system operating under natural convection conditions, with particular emphasis on simple and cost-effective hot-side thermal management. A commercial TEC12703 module was integrated into a miniature refrigeration system consisting of a Styrofoam enclosure, where heat rejection from the hot side was achieved using a folded aluminum plate without any auxiliary cooling components such as fans, pumps, or heat pipes. The aluminum plate was geometrically modified to enhance heat dissipation while maintaining a small footprint and to reduce thermal interaction with the refrigerator wall by increasing the effective separation distance. Experiments were conducted at six different input voltages (3, 4, 5, 6, 7 and 8 V) to evaluate the voltage-dependent cooling behavior and overall system performance under passive cooling conditions. The results demonstrate that even with a simple plate-type heat spreader, stable operation of the thermoelectric module can be maintained, although hot-side temperature rise significantly influences cooling capacity and coefficient of performance (COP) as the input voltage increases. The folded plate configuration achieved up to approximately 2–3 °C lower cold space temperatures and about 15–20% higher COP values compared to the flat plate, particularly within the optimum operating voltage range of 5–6 V. The findings highlight the critical role of hot-side heat rejection in fanless thermoelectric systems and confirm that appropriately designed folded aluminum plates can provide a viable passive thermal management solution for low-power and compact refrigeration applications where simplicity, reliability, and low energy consumption are prioritized.
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ArticleYalnız künye2026/r/ebyu/10183
The thermal-hydraulic performance evaluation of a triangular groove duct with L-shaped baffles: Multi-objective optimization and numerical analysis
Ekiciler, Recep; Demir, Fatih; Kalkan, Orhan
Enhancing heat transfer efficiency is crucial for improving performance and reducing the energy consumption of thermal equipment in various industrial sectors. The emergence of passive enhancement methods, such as corrugated grooves, has improved convective heat transfer cost-efficiently. To this end, this study addresses the thermal and hydraulic performance of the baffle duct with numerical analysis and multi-objective optimization methods. The study is innovative in that it places movable L-shaped baffles inside the duct, which have their own internal connections and a connection to the grooved channel. L-shaped baffles have the ability to move at alpha angles (α = 30°, 60°, 90°) with the upper wall of the duct and at beta angles (β = 60°, 90°, 120°, 150°) with their internal connection points, which affect the thermal and hydraulic performance of the duct. Air, water, mono (GO/water), and tetra hybrid (Al2O3-Au-Ag-TiO2/water) nanofluids are used as coolant fluids in the range of Re = 2500 to 3100. The coolant air and a baffle-less triangular grooved duct are used for comparison to evaluate the thermal and hydrodynamic performance in other cases. The results show that at Re = 2500, the baffled duct achieves a 65% higher Nu than the one without baffles. As α = 90° decreases to 30°, Nu increases by 12.85% and 12.11%, respectively. As β = 60° to 120° increases, Nu increases by 21.67%, while f increases by 59% from β = 90° to 120°. The highest performance evaluation criteria (PEC) is achieved at β = 90° and the lowest at β = 150°. The tetra hybrid nanofluid exhibits the highest Nu and f values across all Re ranges, demonstrating the most efficient cooling performance with a PEC value approximately 8% higher than that of water. Multi-objective optimization reveals that the combination of α = 30°, β = 35°, Re = 2500, and water is the most suitable design. Generally, thermal and hydraulic performance can be significantly improved by carefully selecting channel geometry and fluid properties.
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ArticleYalnız künye2026/r/ebyu/10032
A comprehensive assessment of neutronic and thermal–hydraulic behavior of some advanced accident-tolerant fuels in solid and dual-cooled annular PWR assemblies
Kabach, Ouadie; Uzun, Sinem; Genç, Yasin; Uzun, Bedrettin; Chakir, El Mahjoub; Amsil, Hamid
Accident-tolerant fuel (ATF) concepts are being evaluated to strengthen margins without sacrificing core economics. This study compares five ATF matrices, UN (with natural and enriched nitrogen), UC, UCO, U3Si2, and UAl2, implemented in 17 × 17 solid and 13 × 13 dual-cooled annular PWR lattices. Results show that the multiplication factor decreases monotonically with burnup in both geometries, which allows the use of the linear reactivity model to predict the reactor cycle length; UAl2 and UO2 provide the longest cycles. Assembly-level radial peaking remains low (≈1.05–1.09). All fuel and moderator temperature coefficients are negative, with the strongest feedback in annular UN (Natural N). Solid pins show a single outer-rim power/Pu-239 peak; annular pins split this into two milder rims and flatten the in-pin profile. Prompt (neutron-induced) power is essentially burnup-invariant by normalization, while decay heat grows with matrix density and conversion. Thermal-hydraulic results show that the annular geometry lowers coolant heating and pressure drop and raises the minimum DNBR by ∼ 55–65% relative to solid pins under identical boundary conditions.
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ArticleAçık Erişim2025/r/ebyu/19572
Mıst ülkelerinde sürdürülebilir kalkınma ve yeşil enerjinin yeşil üretime etkisi
Akçayır, Ömer; Akın, Fatih
Çalışmada, MIST (Meksika, Endonezya, Güney Kore ve Türkiye) ülkelerinde sürdürülebilir kalkınma (HDI) ve yenilenebilir (REN) enerji tüketiminin yeşil üretim (CO2) üzerindeki etkilerini araştırmak amacıyla 1990-2021 yılları verileri kullanılarak panel veri analizi yöntemleri kullanılmıştır. CIPS birim kök testinin kullanıldığı analizde tüm serilerin birinci farkta durağan oldukları belirlenmiş, LM Bootstrap eşbütünleşme yöntemiyle eşbütünleşme ilişkisi tespit edilmiştir. Modelin katsayıları Artırılmış Ortalama Grup (AMG) yöntemi ile tahmin edilmiş ve nihayetinde Dumitrescu & Hurlin (2012) panel nedensellik testi ile analiz tamamlanmıştır. Panelin genelinde ve ülke bazında istatistiksel olarak anlamlı sonuçlar ortaya çıkmış, HDI ve yenilenebilir enerji tüketimi CO2’yi azaltırken, kontrol değişken olan GDP ve yenilenemeyen enerji tüketimi CO2’yi artırmaktadır. Sürdürülebilir kalkınmanın yeşil üretim üzerindeki etkisinin yenilenebilir enerjinin etkisinden daha fazla olduğu tespit edilmiştir. Ayrıca bağımsız değişkenlerin her birinden bağımlı değişkene (CO2) doğru, doğrudan ya da diğer değişkenler aracılığıyla dolaylı olarak nedensellik ilişkisi tespit edilmiştir.
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ArticleAçık Erişim2025/r/ebyu/19537
Karbon Emisyonlarını Azaltmada Yenilenebilir Enerjinin Rolü: Çevresel Performans Endeksinde Başarılı Olan 10 Ülkeden Kanıtlar
Akın, Fatih
Günümüzde artan çevresel kaygılar ve iklim değişikliği, yenilenebilir enerji kaynaklarının önemini daha da artırmıştır. Fosil yakıtların kullanımının çevresel etkileri göz önüne alındığında, yenilenebilir enerjiye geçiş, sürdürülebilir bir gelecek için kritik bir adım olarak görülmektedir. Bu bağlamda, yenilenebilir enerji tüketiminin CO2 emisyonları üzerindeki etkilerini anlamak, çevresel politikaların şekillendirilmesi açısından büyük önem taşımaktadır. Bu çalışmanın amacı, 1990-2021 dönemi için çevresel performans endeksinde başarılı olan on ülkenin (Estonya, Lüksemburg, Almanya, Finlandiya, Büyük Britanya, İsveç, Norveç, Avusturya, İsviçre ve Danimarka) yenilenebilir enerji tüketimi (REN) ile CO2 emisyonu arasındaki ilişkiyi incelemektir. Çalışmada, Dinamik Ortak Korelasyon Etkiler (DCCE) ve Panel Vektör Hata Düzeltme Modeli (VECM) Nedensellik testi kullanılarak analizler gerçekleştirilmiştir. DCCE analiz bulguları, hem genel panelde hem de bireysel ülkelerde yenilenebilir enerji tüketimindeki artışın, CO2 emisyonlarını azaltmada önemli bir etkiye sahip olduğunu ortaya koymaktadır. Ayrıca, yapılan panel VECM nedensellik testi bulgusuna göre, yenilenebilir enerji tüketiminden CO2 emisyonuna doğru uzun dönemde nedensellik tespit edilmiştir. Bu bulgular doğrultusunda, çevresel performans endeksinde başarılı olan on ülkenin, yenilenebilir enerji kaynaklarını etkin bir şekilde kullanarak CO2 emisyonlarını azaltmada başarılı olduklarını ve bu sayede sürdürülebilir kalkınma hedeflerine katkıda bulunduklarını ortaya koymaktadır.
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ArticleAçık Erişim2025/r/ebyu/19513
Yeni sanayileşmiş ülkelerde yenilenebilir enerji ve insani gelişmenin ekonomik büyümeye katkısı
Akın, Fatih; Dinçer, Selin
Bu çalışmada 1990-2022 döneminde yeni sanayileşmiş ülkelerde (NIC) (Brezilya, Çin, Hindistan, Endonezya, Malezya, Meksika, Filipinler, Güney Afrika, Tayland, Türkiye) yenilenebilir enerji ve HDI düzeyinin ekonomik büyüme üzerindeki etkisi Artırılmış Ortalama Grup (AMG) tahmincisi ve Juodis, Karavias & Sarafidis (JKS, 2021) Granger nedensellik analizi ile incelenmiştir. LM Bootstrap Panel Eşbütünleşme testi sonuçları yenilenebilir enerji, HDI ve ekonomik büyüme değişkenleri arasında uzun dönemli bir ilişki olduğunu ortaya koymaktadır. Panel AMG tahmin sonuçları panel genelinde yenilenebilir enerji ve HDI düzeyinin ekonomik büyüme üzerinde pozitif ve anlamlı etkisi olduğunu göstermektedir. Ülkelere göre sonuçlar Çin, Hindistan, Endonezya ve Türkiye’de yenilenebilir enerjinin büyüme üzerinde anlamlı ve pozitif bir etkisi olduğunu göstermektedir. Ayrıca, Güney Afrika hariç tüm ülkelerde HDI düzeyinin büyüme üzerinde pozitif ve istatistiksel olarak anlamlı bir etkisi olduğunu göstermektedir. JKS Granger nedensellik testi sonuçları ise HDI ile ekonomik büyüme arasında ve HDI ile yenilenebilir enerji arasında çift yönlü nedensellik bulunduğunu ortaya koymaktadır. Ayrıca ekonomik büyümeden yenilenebilir enerjiye doğru tek yönlü nedensellik tespit edilmiştir. Bulgular, NIC ülkelerinde yenilenebilir enerji ve HDI değerinin ekonomik büyüme üzerinde önemli rol oynadığını vurgulamaktadır.
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ArticleAçık Erişim2025/r/ebyu/19355
The relationship between renewable energy consumption and health expenditures: The case of G-7 countries
Akın, Fatih
This study examines the impact of renewable energy consumption, economic growth, and death rates on healthcare expenditures in G-7 countries over the 1992-2023 period using panel data analysis. Preliminary analyses indicate cross-sectional dependence and heterogeneity across countries. The Fourier LM unit root test reveals that the variables are non-stationary, while the LM Bootstrap cointegration test supports a long-run relationship. Panel-wide AMG estimation results indicate that renewable energy consumption reduces healthcare expenditures, while economic growth and death rates increase healthcare expenditures. Country-based results indicate that renewable energy consumption reduces healthcare expenditures in Germany, Japan, and the United Kingdom. While economic growth increases healthcare expenditures in France, Germany, Italy, and the United Kingdom, death rates increase healthcare expenditures in France, Germany, and the United States, and decrease them in Japan. Furthermore, according to the Dumitrescu & Hurlin causality test, there is a unidirectional causality relationship running from renewable energy consumption and economic growth to healthcare expenditures. The findings show that energy and health policies should be integrated and that renewable energy investments can have positive effects on health systems.
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ArticleAçık Erişim2025/r/ebyu/19352
Effects of rectangular-shaped turbulators on heat transfer, friction factors, and entropy
Fırat, İlker
In this study, the effects of turbulators with different P ratios placed in a circular cross-section test pipe under turbulent flow conditions using water as the working fluid on heat transfer, friction factor (f), and entropy production were investigated using Ansys-Fluent 2021. The lowest Nu was calculated as 111 at Re=11825 for P=6, while the highest Nu was calculated as 219 at Re=19133 for P=1. The increase in Nu values for P = 6, 3, 2, 1.5, 1.2, and 1 compared to the plain pipe is 10.34%-11.64%; 17.39%-18.78%; 25.31%-26.56%; 34.42%-35.88%; 43.53%-44.87%; and 50.36%-51.47%, respectively. In turbulent situations, the highest entropy production rate was found to be 0.3631 W/mK at Re=11825 for P=6, while the lowest entropy production rate was found to be 0.2215 W/mK at Re=19133 for P=1. The minimum and maximum Ns reduction compared to the empty pipe was calculated as 7.13% for Re=19133 at P=6 and 46.62% for Re=11825 at P=1, respectively. In turbulent conditions, the highest Bejan number was found to be 0.9931 at Re=11825 for P=6. As a result, it was concluded that a ratio of P=1 provides maximum benefit in terms of heat transfer, while a ratio of P=6 is ideal in terms of total entropy production.
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