Zeki Yılbaşı

In this study, vehicle-related emissions in Yozgat province were quantified and their impacts on air quality were analyzed. Emission calculations were performed based on traffic density and vehicle categories using data obtained from the General Directorate of Highways, and the resulting estimates were compared with data from the National Air Quality Monitoring Network. Within the scope of the study, road transport–related emissions of CO, NOₓ, VOC, and PM in Yozgat province were calculated according to road segments and vehicle types, revealing that emission levels exhibit spatial variations depending on traffic intensity and route characteristics. The findings indicate that gasoline-powered vehicles contribute more significantly to CO and VOC emissions, whereas diesel-powered light commercial vehicles and buses are the primary sources of NOₓ and PM emissions. Consequently, promoting the use of alternative fuels and improving public transportation systems are recommended in order to reduce vehicle-related pollution.

This study evaluated diesel-hazelnut oil biodiesel-butanol triple fuel blends as a potential alternative fuel for diesel engines. Hazelnut oil was converted to biodiesel using transesterification and blended with diesel fuel and butanol at various ratios. Engine performance parameters like brake-specific fuel consumption (BSFC), brake thermal efficiency (BTE) and exhaust gas temperature (EGT) were analyzed. Emissions of NOx, smoke-opacity, HC, CO2, and CO were also measured. Fuel consumption increased slightly with butanol content due to the lower energy density. However, BTE was largely unaffected by oxygen-enhanced combustion. Exhaust gas temperature decreased for blends containing butanol due to factors like latent heat and oxygen content. CO and HC emissions were significantly reduced by up to 32% and 23%, respectively, for the highest butanol blend due to increased oxygen. NOx emissions were also reduced in comparison to diesel, with reductions up to 21%, likely due to lower combustion temperatures. Smoke opacity decreased between 13 and 69% for blends versus diesel. Overall, study demonstrated that these triple-blends can be utilized as an alternative fuel in unmodified diesel engines. The blends performed comparably to diesel efficiency while lowering most exhaust emissions. However, further testing under different operating conditions is needed to validate the long-term impacts.

The imperative to decarbonize global energy systems and enhance energy security necessitates a transition towards ecofuels, broadly classified as biofuels, waste-derived fuels, and electrofuels (e-Fuels). The primary goal of this review is to provide a holistic and comparative evaluation of these three pivotal ecofuel pillars under a unified framework, identifying their strategic niches in the energy transition by critically assessing their interconnected technical, economic, and policy challenges. It offers a comparative dissection of inherent resource constraints, spanning biomass availability, the immense scale of renewable electricity required for e-Fuels, sustainable carbon dioxide (CO₂) sourcing, and the complexities of utilizing non-biodegradable wastes, identifying that true feedstock sustainability and holistic lifecycle management are paramount, cross-cutting limitations for all pathways. This review critically highlights how the current global reliance on fossil fuels for electricity production (approx. 60%) and the upstream emissions embodied in renewable energy infrastructure challenge the climate neutrality claims of ecofuels, particularly e-Fuels, underscoring the necessity for comprehensive well-to-wheels (WtW) lifecycle assessments (LCAs) over simpler tank-to-wheels (TtW) approaches. This perspective is crucial as emerging regulations demand significant greenhouse gas (GHG) emission reductions (70–100%) compared to fossil fuels. Ultimately, this synthesis argues for a nuanced, technologically neutral deployment strategy, prioritizing specific ecofuels for hard-to-abate sectors, and underscores the urgent need for stable, long-term policies coupled with robust and transparent LCA methodologies to guide a truly sustainable energy transition.

Renewable energy and its many forms, have been the focus of major interests because of their energy potential and environmental benefits, are now emerging as subjects that need more investigation, particularly in relation to biodiesel fuel. This is due to the uncertainty surrounding oil prices and emission regulations. The study included NaOH concentration (0.6, 0.8, 1, and 1.2 wt.%), ethanol:oil molar ratio (6:1, 8:1, 10:1, and 12:1), temperature of reaction (30, 45, 60, and 75 °C), and duration of reaction (30, 45, 60, and 75 min) as significant parameters influencing the yield of ethyl ester. For the first time, to the best of our knowledge, the L16 orthogonal design matrix of the Taguchi method approach was applied in the present research to optimize the transesterification step parameters from linseed oil. ANOVA validation studies determined the relative influence of the process parameters. A maximum biodiesel yield of 95.20% was obtained under optimum reaction conditions: 1 wt% NaOH, 10:1 ethanol:oil molar ratio, 75°C reaction temperature and 60 min reaction time. The highest contribution ranking of the four variables was 48.95% with the ethanol:oil molar ratio, 22.32% with NaOH loading, 18.24% with the temperature of the reaction, and 9.59% with the duration of the reaction. The fuel properties of synthesized linseed oil ethyl ester, at the specified ideal reaction conditions, were met the range of the standard EN14214.

This study applies three different artificial intelligence algorithms (Multi-layer Perceptron (MLP), Extreme Gradient Boosting (XGBoost), and Support Vector Machine (SVM)) to estimate CO₂ emissions in Türkiye’s transportation sector. The input parameters considered are Energy consumption (ENERGY), Vehicle Kilometers (VK), POPulation (POP), Year (Y), and Gross Domestic Product Per Capita (GDP). Strong correlations are observed, with ENERGY having the highest correlation followed by VK, POP, Y, and GDP. Four scenarios are designed based on the correlation effect: scenario 1 (ENERGY/VK/POP/Y/GDP), scenario 2 (ENERGY/VK/POP/Y), scenario 3 (ENERGY/VK/POP), and scenario 4 (ENERGY/VK). Experiments compare their effects on CO₂ emissions using statistical indicators (R², RMSE, MSE, and MAE). Across all scenarios and algorithms, R² values range from 0.8969 to 0.9886, and RMSE values range from 0.0333 to 0.1007. The XGBoost algorithm performs best in scenario 4. Artificial intelligence algorithms prove successful in estimating CO₂ emissions. This study has significant implications for policymakers and stakeholders. It highlights the need to review energy investments in transportation and implement regulations, restrictions, legislation, and obligations to reduce emissions. Artificial intelligence algorithms offer the potential for developing effective strategies. Policymakers can use these insights to prioritize sustainable energy investments. In conclusion, this study provides insights into the relationship between input parameters and CO₂ emissions in the transportation sector. It emphasizes the importance of proactive measures and policies to address the sector’s environmental impact. It also contributes to the understanding of AI-assisted CO₂ emissions forecasting in the transport sector, potentially informing future policy decisions aimed at emission reduction and sustainable transport development.

This study focuses on the optimization of biodiesel synthesis using non-edible hempseed oil as the feedstock. The response surface method was used to find the best methanol: oil molar ratio, catalyst concentration, reaction temperature, and reaction duration for the transesterification process. The center composite design experimental design was used to make the design. A total of 30 cycles were conducted to adjust the four parameters at five different levels in order to optimize the biodiesel production process. It was found that the best conditions for transesterification of hempseed oil were a KOH catalyst concentration of 0.80 wt.%, a molar ratio of 7.41:1, a reaction time of 62.83 min, and a reaction temperature of 61.92 °C. Under these optimized reaction conditions, the predicted biodiesel yield was 95.57%, while the experimental yield was 95.24%. The biodiesel produced using the optimized parameters was analyzed for its properties, and the findings demonstrated that it met the requirements of EN 14214, a standard for biodiesel quality. The optimization of the biodiesel synthesis process using non-edible hempseed oil contributes to the exploration of alternative and sustainable feedstocks for biodiesel production. The values of the produced biodiesel within the standard range demonstrate its suitability for commercial applications and strengthen the potential of hemp seed oil as a suitable raw material for biodiesel production.

In this study, it was aimed to examine the influences of biodiesel–diesel-higher alcohol (1-pentanol, 1-hexanol, and 1-heptanol) blends on the performance, emission and combustion behaviors of a single-cylinder diesel engine. The tests were performed at a fixed speed of 1500 rpm and variable loads (25%, 50%, 75%, and 100%). For the tests, 80% diesel and 20% hemp seed oil biodiesel were blended and called as B20. Biodiesel fuel was produced by transesterification from hemp seed oil in the presence of methanol and potassium hydroxide for the preparation of B20 binary test fuel and other ternary fuels. Furthermore, nine ternary blend fuels [20% HSOB + 70%, 60% and 50% diesel, respectively + 10%, 20% and 30% higher alcohol (pentanol, hexanol and heptanol) respectively] were prepared. The calculations made with the experimental data revealed that the minimum brake specific energy consumption values were 12,48 MJ/kW h, 13,06 MJ/kW h, 13,27 MJ/kW h, 13,35 MJ/kW h, 13,47 MJ/kW h, and 13,59 MJ/kW h, respectively, for diesel fuel at full load, for fuels B20, B20Hx10, B20Hp10, B20Hx20 and B20Pe10, the maximum brake thermal efficiency values were obtained as 28.85%, 27.56%, 27.14%, 26.97%, 26.73% and 26.49%, respectively, for the same fuels at the same load. The increment in higher alcohol concentration in the blend delayed start of combustion and therefore the ignition delay period was prolonged. In the fuel line pressure data, changes were observed depending on the amount, viscosity and density of the fuel. Furthermore, B20Hx10 and B20Hp10 fuels gave the maximum in-cylinder pressure, heat release rate, average gas temperature and pressure rise rate values after diesel and biodiesel. The addition of biodiesel and higher alcohol to diesel fuel resulted in a decrease in NO_X, CO and unburned HC and smoke emissions and an increase in CO₂. NO_X, CO and unburned HC values of higher alcohol blended fuels at full load showed lower results, between 3.04–22.24%, 22.85–56.35% and 5.44–22.83%, respectively, compared to diesel fuel. It can be concluded that the use of hemp seed oil biodiesel and higher alcohol in the diesel engine will make a significant contribution to the reduction of NO_X emissions.

The core focus of the present investigation is regarding biodiesel production from industrial hemp seed oil applying single-stage homogenous catalyzed transesterification process obtaining high yield of methyl ester. The engine tests were carried out on a single-cylinder, four-stroke, water-cooled, unmodified diesel engine operating with hemp seed oil methyl ester as well as its blends with conventional diesel fuel. The experimental findings of the test fuels were compared with those from diesel. The results pointed out that the performance and combustion behaviors of biodiesel fuels are just about in line with those of diesel fuel propensity. The specific fuel consumption for 5% biodiesel blend (0.291 kg/kW h), 10% biodiesel blend (0.305 kg/kW h), and 20% biodiesel blend (0.312 kg/kW h) blends at full load was closer to diesel (0.275 kg/kW h). In the meantime, the thermal efficiency for biodiesel was found to be at the range of 15.98–24.97% and it was slightly lower than that of diesel (18.10–29.85%) at the working loads. On the other hand, the harmful pollutant characteristics of carbon monoxide, hydrocarbon, and smoke opacity for biodiesel and its blends were observed to be lower in comparison with diesel during the trials. However, the oxides of nitrogen emissions for biodiesel were monitored to be as 6.85–15.40 g/kW h which was remarkably higher than that of diesel (4.71–8.63 g/kW h). Besides that, the combustion behaviors of biodiesel and its blends with diesel showed much the same followed those of diesel. Namely, the duration of ignition delay of biodiesel–diesel blends was shorter than that of diesel fuel because of the higher cetane number specification of the methyl ester. The highest gas pressures inside the cylinder as well as the rates of the heat release of biodiesel including test fuels are lower in contrast to the diesel due to the shorter ignition delay. It could be concluded that the utilization of biodiesel produced from industrial hemp seed oil in the diesel engine up to 20% (by vol.) will decrease the consumption of diesel and environmental pollution, especially in developing countries.