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Hybrid energy storage systems (HESSs) play a crucial role in enhancing the performance of electric vehicles (EVs). However, existing energy management optimization strategies (EMOS) have limitations in terms of ensuring an accurate and timely power supply from HESSs to EVs, leading to increased power loss and shortened battery lifespan. To ensure an accurate and timely power supply from HESSs to EVs, this paper proposes a dual-layer multi-mode (DLMM) EMOS. This strategy comprises two layers. The upper layer is a backpropagation neural network (BPNN) model enhanced by the particle swarm optimization (PSO) algorithm. It is used for real-time HESS power demand prediction. In the lower layer, a HESS operational mode determination process is formulated, and an objective optimization function is established based on HESS power loss. Under constraints designed according to the HESS state parameters, the PSO algorithm is utilized to search for the optimal power allocation ratio of the HESS in real time. The proposed DLMM-EMOS strategy is capable of providing optimal power reference values for the batteries and ultracapacitors of the HESS. The DLMM-EMOS is tested on an electrical experimental platform using US06, NEDC, and WLTP driving cycles. Results indicate that the DLMM-EMOS effectively reduces the HESS power loss while enhancing the driving range of the battery. [ABSTRACT FROM AUTHOR]

In recent years, U3Si2 has been proposed as an alternative nuclear fuel material to uranium dioxide (UO2) because of its intrinsically high uranium density and thermal conductivity. However, the operation environment in the nuclear reactor is complex and extreme, such as in-pile neutron irradiation, and thus it is necessary to explore the radiation response behavior of U3Si2 and the physical properties of its damaged states. In the present study, first-principles calculations based on density functional theory were carried out to investigate the mechanical and electronic properties of defective U3Si2. Our results showed that the defect stability in U3Si2, except its interstitial defects, is dependent on its chemical environment. When vacancy, antisite or interstitial defects are introduced into U3Si2, its elastic modulus are decreased and its ductility is enhanced. Although the presence of defects in U3Si2 does not change its metallic nature and the electron distribution in its Fermi level, their effect on the partial chemical bonding interaction is significant. This study suggests that under a radiation environment, the created defects in U3Si2 remarkably affect its mechanical and electronic properties. [ABSTRACT FROM AUTHOR]

High entropy alloys (HEAs) are composed of multiple main metal elements and have attracted wide attention in various fields. In this study, a novel Ti0.20Zr0.20Hf0.20Nb0.40 HEA was synthesized and its hydrogenation properties were studied, including sorption thermodynamics and hydrogen absorption/desorption kinetics. The maximum hydrogen absorption capacity was 1.5 H/atom at 573 K. X-ray diffraction (XRD) analysis indicated that the crystal structure of Ti0.20Zr0.20Hf0.20Nb0.40 HEA transformed from body-centered cubic (BCC) to body-centered tetragonal (BCT) with increasing hydrogen content, and to face-centered cubic (FCC) after hydrogen absorption to saturation. As a multi-principal element alloy, the Ti0.20Zr0.20Hf0.20Nb0.40 HEA possesses unique hydrogen absorption characteristics. The hydrogen absorption platform pressure rises gradually with the increase of the hydrogen absorption amount, which is caused by multiple kinds of BCT intermediate hydrides with consecutively increasing c/a. The full hydrogen absorption of the Ti0.20Zr0.20Hf0.20Nb0.40 HEA was completed in almost 50 s, which is faster than that of the reported hydrogen storage alloys in the literature. The experimental results demonstrate that the Ti0.20Zr0.20Hf0.20Nb0.40 HEA has excellent kinetic properties, unique thermodynamic hydrogen absorption performance, as well as a low plateau pressure at room temperature. [ABSTRACT FROM AUTHOR]

In the past decades, uranium silicide (U 3 Si 2 ) as a promising accident tolerant fuel (ATF) has drawn considerable attention in the field of nuclear physics. In comparison with traditional nuclear fuel (UO 2 ), the U 3 Si 2 has higher thermal conductivity and uranium density, thereby resulting in lower centerline temperatures and better fuel economy. However, during the nuclear fission reaction, some unexpected fission products, such as Xe and Cs, are released and form the defective states. In this study, we explore the influence of Xe and Cs on the thermal conductivity of the U 3 Si 2 lattice from 200 to 1500 K using density functional theory calculations combined with Boltzmann transport equation. Our results reveal that the lattice and electronic thermal conductivities of defective U 3 Si 2 are reduced at a constant temperature, as compared with that of ideal system, thus resulting in a decrease of the total thermal conductivity. In the case of Cs occupation at U1 site, the total thermal conductivity (4.42 W mK -1 ) is decreased by ∼56% at 300 K, as compared with the value of 9.99 W mK -1 for ideal system. With U1 and Si sites being occupied by Xe, the total thermal conductivities (4.45 and 6.52 W mK -1 ) are decreased by ∼55% and 35% at 300 K, respectively. The presented results suggest that the U 3 Si 2 has potential as a promising ATF at high temperatures., (© 2023 IOP Publishing Ltd.)

In recent years, U 3 Si 2 has been proposed as an alternative nuclear fuel material to uranium dioxide (UO 2 ) because of its intrinsically high uranium density and thermal conductivity. However, the operation environment in the nuclear reactor is complex and extreme, such as in-pile neutron irradiation, and thus it is necessary to explore the radiation response behavior of U 3 Si 2 and the physical properties of its damaged states. In the present study, first-principles calculations based on density functional theory were carried out to investigate the mechanical and electronic properties of defective U 3 Si 2 . Our results showed that the defect stability in U 3 Si 2 , except its interstitial defects, is dependent on its chemical environment. When vacancy, antisite or interstitial defects are introduced into U 3 Si 2 , its elastic modulus are decreased and its ductility is enhanced. Although the presence of defects in U 3 Si 2 does not change its metallic nature and the electron distribution in its Fermi level, their effect on the partial chemical bonding interaction is significant. This study suggests that under a radiation environment, the created defects in U 3 Si 2 remarkably affect its mechanical and electronic properties.