Hasil untuk "Fuel"

G. Cahill, M. Herrera, A. Morgan et al.

A. Oasmaa, S. Czernik

L. Carrette, K. Friedrich, U. Stimming

X. Ren, P. Zelenay, Sharon C. Thomas et al.

Andrei Kulikovsky

We have developed a non-isothermal analytical model for the impedance of the cathode catalyst layer (CCL) in a PEM fuel cell. In-phase harmonic perturbations to the current density and temperature reduce the impedance and the static polarisation resistivity of the CCL due to lowering proton transport losses. A special selection of the current and temperature perturbation amplitudes allows for complete elimination of these losses.

A. Ghenciu

Mack Wesley Cleveland, Andrew Nelson, Ericmoore Jossou

UO2 doped with parts per million Cr2O3 powder is considered a potential near term accident tolerant fuel candidate. Here, the results of decades of industry and academic research into Cr-doped UO2 are analyzed and their shortcomings are critiqued. Focusing on the incorporation mechanisms of Cr into the fuel matrix, we explore a mechanistic understanding of the characteristic properties of Cr-doped UO2, notably, enhanced fission gas retention attributed to enlarged grain sizes following sintering, along with marginal improvements in the thermophysical properties. The findings of recent X-ray Adsorption Near Edge Spectroscopy studies were compared and put into conversation with historic data regarding the incorporation of Cr in UO2. On the basis of defect mechanisms, the case is made for the substitutional incorporation of Cr governing the lattice solubility but not the enhanced U diffusivity. Instead, Cr/Cr2O3 redox chemistry in a well-defined oxygen potential explains the differences in the U diffusivity and O/M ratio. The primary mechanism of doping-enhanced grain growth is found to be liquid assisted sintering due to a CrO(l) eutectic phase at the grain boundaries. The role of inhomogeneities in Cr concentration in UO2 at various length scales across the materials microstructure is highlighted and connected to promising experimental and modeling work to fill in the gaps in the current understanding of Cr-doped UO2. The review ends with an outline of future works that combine meticulous irradiation studies and high resolution experiments with next generation modeling and simulations techniques empowered by machine learning advances to accelerate the fabrication and adoption of Cr-doped UO2 light water reactors.

Gabriel Jarry, Ramon Dalmau, Philippe Very et al.

Accurate modelling of aircraft fuel-flow is crucial for both operational planning and environmental impact assessment, yet standard parametric models often neglect performance deterioration that occurs as aircraft age. This paper investigates multiple approaches to integrate engine ageing effects into fuel-flow prediction for the Airbus A320-214, using a comprehensive dataset of approximately nineteen thousand Quick Access Recorder flights from nine distinct airframes with varying years in service. We systematically evaluate classical physics-based models, empirical correction coefficients, and data-driven neural network architectures that incorporate age either as an input feature or as an explicit multiplicative bias. Results demonstrate that while baseline models consistently underestimate fuel consumption for older aircraft, the use of age-dependent correction factors and neural models substantially reduces bias and improves prediction accuracy. Nevertheless, limitations arise from the small number of airframes and the lack of detailed maintenance event records, which constrain the representativeness and generalization of age-based corrections. This study emphasizes the importance of accounting for the effects of ageing in parametric and machine learning frameworks to improve the reliability of operational and environmental assessments. The study also highlights the need for more diverse datasets that can capture the complexity of real-world engine deterioration.

K. Nevin, H. Richter, Sean F. Covalla et al.

R. Quadrelli, Sierra Peterson

M. Parikka

Murat Senzeybek, Mario Feinauer, Isheeka Dasgupta et al.

This study presents a carbon dioxide (CO₂), exhaust particulate matter (PM_2.5) and nitrogen oxide (NO_x) tailpipe emission analysis of passenger cars in nine countries, representing different world regions up to 2050 using a bottom-up calculation method. A diffusion model is used to analyze the development of different drivetrain/fuel technologies in the respective vehicle stocks of each world region. Drivetrain- and country-specific emission factors are weighted according to the modelled stock compositions. The obtained stock fleets’ average emission factors are multiplied by the transport demand in order to obtain the total passenger car emissions. Our findings reveal global passenger car CO₂, NO_x and PM_2.5 emissions decrease by approximately 45%, 63% and 54%, respectively, between 2015 and 2050. Gasoline will remain a significant energy carrier in 2050 with about a 25% stock share. However, electric vehicles will be in the lead, especially after 2040. Additionally, rising transport demand offsets emission reductions in some regions. This study aims to provide global and regional insights into future emissions trends and their driving factors.

yinuo wang, Muhammad Umair, Assilova Aizhan et al.

The persistent disparity between urban and rural incomes in China poses a critical challenge to alleviating energy poverty in rural areas. This study investigates how the income gap between urban and rural regions exacerbates rural energy poverty, focusing on the period from 2005 to 2023, utilizing data from 30 provinces. By employing a two-way fixed-effects model and asymmetry analysis, the research reveals that an increase in the urban-rural income disparity significantly intensifies rural energy poverty. Notably, at higher income quantiles, the gap's effect on energy poverty is more pronounced, while at lower quantiles, its impact is less severe. Financial development, rather than alleviating the situation, is positively associated with rural energy poverty, highlighting an unintended consequence of unequal access to financial services. The results further show that rural regions with limited financial inclusion experience a deepening of energy poverty, with financial service accessibility benefiting wealthier demographics more than the impoverished rural population. These findings imply that targeted policies promoting equitable financial access, narrowing income disparities, and integrating energy poverty reduction strategies are essential to achieving China's Rural Revitalization Strategy.

Nugraha Anggara Trisna, Ahmad Putra Zindhu Maulana, Santoso Mardi et al.

Electrical energy is one of the most important basic human needs and is used in everyday life in various activities. Over time, the need for electricity will increase due to the increase and development of both the population, the amount of in-vestment and technological developments. The use of coal as the main fuel for power plants is also running low and its existence is not renewable. One solution to deal with these problems is the utilization of renewable energy. One type of re-newable energy that is environmentally friendly in order to meet the needs of electrical energy is solar energy. The existence of solar energy which is very abundant is one solution to reducing fossil fuels, which are currently running low. In PPNS Baruna 01 Crewboat the DC power source used comes from Solar Panels with a total of two pieces and each power is 300WP. As we know solar energy is fluctuating (up and down), therefore a DC-DC converter is needed so that the resulting voltage is stable. The DC-DC converter used in this research is a buck-boost converter. This buck-boost converter is designed with a set point of 14.4V which is then used for battery charging. The components used are 22.5μH inductor, 2275μF capacitor, resistor, diode and mosfet. The simulation results of the buck-boost converter in PSIM software show that the converter is able to work in two modes with an output voltage in accordance with the set point. When buck mode the input voltage is 24V to 14.4V and when boost mode the input voltage is 12V to 14.4V. From the simulation results, the buck-boost converter can be realized on the PLTS in the PPNS Baruna 01 Crewboat.

J. Andújar, F. Segura

O. Kurmi, S. Semple, P. Simkhada et al.

Harish R. Gadey, Kacey D. McGee, Patrick D. Royer

The US Department of Energys Office of Nuclear Energy is planning for an integrated waste management approach to transport, store, and eventually dispose of spent nuclear fuel and other high-level radioactive waste as part of the Integrated Waste Management program. In support of this effort, the Stakeholder Tool for Assessing Radioactive Transportation is being developed within the IWM program. This is a web-based decision support tool that can be used to analyze geospatial data related to the transportation of SNF and HLW.

Abderrahmane Feriel, Amoros Fabian, Sammari Wael et al.

Maritime transport is one of the main drivers of a country’s economic growth. Up to 90% of world trade is carried out by sea. However, the high consumption of fossil fuels leads to significant greenhouse gas emissions and other pollutants emissions, such as the nitrogen dioxide (NOx) and the sulfur oxides (SOx). Decarbonizing maritime transport, through the transition to electrified propulsion, is a major challenge for researchers and engineers in the naval construction sector. This paper studies electric, thermal and hybrid energy/propulsion solutions for ships serving the island of Ouessant, located near Brittany’s coast in France. Using a simplified methodology based on power flows between the various components (batteries, generators, fuel cells), the most suitable type of energy is investigated according to the case study, for efficient and effective vessel use. The simulations show that the energy consumption of the fully electric solution is the best with 5.78 MWh consumed against, for example, 13.89 MWh equivalent of fuel for the classic diesel topology.

Federico Capra, Diego Abalos, Stefania Codruta Maris et al.

Abstract Digestate, a by‐product of biogas production, is widely recognized as a promising renewable nitrogen (N) source with high potential to replace synthetic fertilizers. Yet, inefficient digestate use can lead to pollutant N losses as ammonia (NH3) volatilization, nitrous oxide (N2O) emissions and nitrate (NO3−) leaching. Cover crops (CCs) may reduce some of these losses and recycle the N back into the soil after incorporation, but the effect on the N balance depends on the CC species. In a one‐year field study, we tested two application methods (i.e., surface broadcasting, BDC; and shallow injection, INJ) of the liquid fraction of separated co‐digested cattle slurry (digestate liquid fraction [DLF]), combined with different winter cover crop (CC) options (i.e., rye, white mustard or bare fallow), as starter fertilizer for maize. Later, side‐dressing with urea was required to fulfil maize N‐requirements. We tested treatment effects on yield, N‐uptake, N‐use efficiency parameters, and N‐losses in the form of N2O emissions and NO3− leaching. CC development and biomass production were strongly affected by their contrasting frost tolerance, with spring‐regrowth for rye, while mustard was winter killed. After the CCs, injection of DLF increased N2O emissions significantly compared with BDC (emission factor of 2.69% vs. 1.66%). Nitrous oxide emissions accounted for a small part (11%–13%) of the overall yield‐scaled N losses (0.46–0.97 kg N Mg grain−1). The adoption of CCs reduced fall NO3− leaching, being 51% and 64% lower for mustard and rye than under bare soil. In addition, rye reduced NO3− leaching during spring and summer after termination by promoting N immobilization, thus leading to −57% lower annual leaching losses compared with mustard. DLF application method modified N‐loss pathways, but not the cumulative yield‐scaled N losses. Overall, these insights contribute to inform an evidence‐based design of cropping systems in which nutrients are recycled more efficiently.

Walter Leal Filho, Diogo Guedes Vidal, Maria Alzira Pimenta Dinis et al.