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《Journal of the European Ceramic Society》2021,41(13):6596-6605
This work focuses on identifying the rate-determining step of oxygen transport through La0.5Sr0.5Fe0.7Ga0.3O3-δ membranes with symmetric and asymmetric architectures. The best oxygen semipermeation fluxes are 3.4 10−3 mol. m-2.s-1 and 6.3 10−3 mol. m-2.s-1 at 900 °C for the symmetric membrane and asymmetric membrane with a modified surface. The asymmetric membrane with a modified surface leads to an increase of approximately 7 times the oxygen flux compared to that obtained with the La0.5Sr0.5Fe0.7Ga0.3O3-δ dense membrane without surface modification. This work also shows that the oxygen flux is mainly governed by gaseous oxygen diffusion through the porous support of asymmetric La0.5Sr0.5Fe0.7Ga0.3O3-δ membranes. 相似文献
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El-Hokayem Antoine Falcone Yliès 《International Journal on Software Tools for Technology Transfer (STTT)》2022,24(2):159-181
International Journal on Software Tools for Technology Transfer - We use runtime verification (RV) to check various specifications in a smart apartment. The specifications can be broken down into... 相似文献
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《International Journal of Hydrogen Energy》2022,47(91):38721-38735
Proper management of the liquid water and heat produced in proton exchange membrane (PEM) fuel cells remains crucial to increase both its performance and durability. In this study, a two-phase flow and multicomponent model, called two-fluid model, is developed in the commercial COMSOL Multiphysics® software to investigate the liquid water heterogeneities in large area PEM fuel cells, considering the real flow fields in the bipolar plate. A macroscopic pseudo-3D multi-layers approach has been chosen and generalized Darcy's relation is used both in the membrane-electrode assembly (MEA) and in the channel. The model considers two-phase flow and gas convection and diffusion coupled with electrochemistry and water transport through the membrane. The numerical results are compared to one-fluid model results and liquid water measurements obtained by neutron imaging for several operating conditions. Finally, according to the good agreement between the two-fluid and experimentation results, the numerical water distribution is examined in each component of the cell, exhibiting very heterogeneous water thickness over the cell surface. 相似文献
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《International Journal of Hydrogen Energy》2022,47(5):3022-3032
In the present work, the bonding length, electronic structure, stability, and dehydrogenation properties of the Perovskite-type ZrNiH3 hydride, under different uniaxial/biaxial strains are investigated through ab-initio calculations based on the plane-wave pseudo-potential (PW-PP) approach. The findings reveal that the uniaxial/biaxial compressive and tensile strains are responsible for the structural deformation of the ZrNiH3 crystal structure, and its lattice deformation becomes more significant with decreasing or increasing the strain magnitude. Due to the strain energy contribution, the uniaxial/biaxial strain not only lowers the stability of ZrNiH3 but also decreases considerably the dehydrogenation enthalpy and decomposition temperature. Precisely, the formation enthalpy and decomposition temperature are reduced from ?67.73 kJ/mol.H2 and 521 K for non-strained ZrNiH3 up to ?33.73 kJ/mol.H2 and 259.5 K under maximal biaxial compression strain of ε = ?6%, and to ?50.99 kJ/mol.H2 and 392.23 K for the maximal biaxial tensile strain of ε = +6%. The same phenomenon has been also observed for the uniaxial strain, where the formation enthalpy and decomposition temperature are both decreased to ?39.36 kJ/mol.H2 and 302.78 K for a maximal uniaxial compressive strain of ε = - 12%, and to ?51.86 kJ/mol.H2 and 399 K under the maximal uniaxial tensile strain of ε = +12%. Moreover, the densities of states analysis suggests that the strain-induced variation in the dehydrogenation and structural properties of ZrNiH3 are strongly related to the Fermi level value of total densities of states. These ab-initio calculations demonstrate insightful novel approach into the development of Zr-based intermetallic hydrides for hydrogen storage practical applications. 相似文献
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《Journal of the European Ceramic Society》2020,40(12):4217-4223
Unlike fracture toughness, the notch fracture toughness of a ceramic is not a constant; rather, it increases with the notch-root radius ρ in a notched specimen. In this study, by analyzing the fracture measurements of eight different notched ceramics with an average grain size G of 3–40 μm, a simple model describing the relation between the notch fracture toughness and fracture toughness is proposed as a function of the relative notch-root radius ρ/G. The normal distribution is incorporated to consider the inevitable scatter in measurements where fracture mechanisms and errors are present. The results demonstrate that the model can effectively predict the quasi-brittle fracture variation trend for ceramics, including the upper and lower bounds, with 96% reliability, from a normal distribution; thus, it can address virtually all of the experimental data. We also determined that the notch fracture toughness approximates the fracture toughness if ρ ≤ G. 相似文献
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《International Journal of Hydrogen Energy》2020,45(55):30942-30956
Accurate remaining useful life (RUL) prediction of proton exchange membrane fuel cells (PEMFCs) can assess the reliability of fuel cells to determine the occurrence of failures and mitigate their operational risk. However, is it quite challenging to design a high-precision prediction method because the implicit degradation details of PEMFCs are difficult to learn well from the measurement data with high-frequency noise. Recognizing this, a novel RUL prediction method based on singular spectrum analysis (SSA) and deep Gaussian process (DGP) is proposed in this paper. The SSA-based method is firstly employed to preprocess the measurement data, which can strengthen the effective information of PEMFC degradation data at the same time remove the noise and spikes that interfere with degradation prediction. As a deep structural model, DGP has strong feature learning ability which can represent the nonlinear details of degradation data and give more accurate prediction results. At the same time, it serves as a probabilistic model that can provide the confidence interval to enhance reliability of RUL prediction. The effectiveness of the proposed method is evaluated by experimental data of the PEMFCs under steady-state conditions, and the results show that the SSA-DGP method has higher accuracy and reliability than conventional methods. 相似文献
9.
《Intermetallics》2015
The substantial heat generated in three-dimensional integrated circuits and high-power electronics has made thermal management a critical challenge for reliability in the electronics industry. Pure indium solder has been used as a thermal interface material to minimize the contact thermal resistance between a chip and its heat sink. Indium and indium-based alloys are potential lead-free solder for low-temperature applications. Heat sinks in the heat dissipation system as well as substrates of electronic joints are usually made of copper, with nickel being the most commonly used diffusion barrier on the chip side. Therefore, the Cu/In/Ni sandwich structure would be encountered in electronic devices. The soldering process for forming the Cu/In/Ni structure crucially determines the reliability of devices. In this study, Cu/In/Ni interfacial reactions at 280 °C were investigated. Intermetallic compounds were identified and the microstructural evolution was observed. A strong coupling effect between Cu and Ni was found, which caused several peculiar phenomena: (1) the formation of a Cu–In compound (the Cu11In9 phase) at the In/Ni interface; (2) the formation of two sub-layers of the Cu11In9 phase at the Cu/In interface; (3) the formation of faceted rod-like Cu11In9 grains; and (4) the formation of a half-Cu11In9, half-Ni3In7 microstructure after prolonged reactions. The mechanism of phase transformations is elucidated based on the calculated Cu–In–Ni ternary phase diagram using CALPHAD thermodynamic modeling. 相似文献
10.
Wang Tao Semenov Sergey Wang Engang Delannoy Yves Fautrelle Yves Budenkova Olga 《Metallurgical and Materials Transactions B》2019,50(6):3039-3054
Metallurgical and Materials Transactions B - Modeling of equiaxed solidification is vital for understanding the solidification process of metallic alloys. In this work, an extended literature... 相似文献