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Commercial Ni-YSZ anodes of solid oxide fuel cells (SOFCs) are susceptible to carbon deposits using hydrocarbons as fuel. Herein, we explore a simple approach of low fuel partial pressure to investigate the relevant limiting factors for ethanol-fueled SOFCs, providing the evaluation of the electrochemical performance and the carbon tolerance. As the partial pressure of ethanol fuel increases from 30% to 60%, the best cell performance gradually increases from 710.2 mW cm−2 to 856.8 mW cm−2 at 800 °C, which still lower than those of hydrogen-fueled SOFCs (1061.4 mW cm−2 at 800 °C), and the corresponding improvement in concentration polarization can be clearly observed especially in high current discharge area. The corresponding impedance spectra and electrode polarization processes of ethanol-fueled SOFCs are further studied by the equivalent circuit fitting and the distribution function of relaxation time (DRT) analysis, finding that the key improvement of the speed control steps comes from the concentration polarization process with the increase of the fuel partial pressure. Small amount of carbon deposition is observed on the Ni-YSZ anode substrate by SEM-EDS images after short-term discharging testing, and the safety utilization boundaries of ethanol-fueled SOFCs with a certain steam concentration can be predicted by the thermodynamic equilibria calculation. • Ethanol-fueled SOFCs with low fuel partial pressure are evaluated. • Low fuel partial pressure leads to the cell concentration polarization. • Electrode polarization processes are studied by the DRT analysis. • Safety utilization boundaries can be predicted by the thermodynamic equilibria calculation. [ABSTRACT FROM AUTHOR]

• Considering the spatial–temporal correlation of random matrices, a system operating state analysis method based on the single-ring theorem and correlation coefficient analysis is proposed to provide the basis for low-quality PMU data identification to determine the reasons for PMU data mutations. • Starting from singular value decomposition and reconstruction, a low-quality PMU data identification method based on the spatial–temporal correlation between original data and low-rank reconstructed data is proposed under different operating states. • The physical meanings of singular value decomposition are analyzed, and a dynamic threshold selection method is adopted for low-quality PMU data identification criteria based on the spatial–temporal correlation to improve the identification accuracy. With the high access of renewable energy, complex and changeable transmission networks, and frequent load interactions, the dynamic characteristics of low-carbon power systems have become more complex and random. The 10 ms-level dynamic measurement data of Phasor Measurement Unit are the basis for dynamic awareness, control and decision. However, the phenomenon of low-quality data usually exists in PMU measurements. Considering the spatial–temporal correlation reflected by the random matrix single-ring theorem and correlation coefficients, two system operating states and two types of low-quality PMU data are determined. Based on singular value decomposition and reconstruction, the distribution of the residuals between the original data and reconstructed data is analyzed to realize low-quality PMU data identification. To improve the identification accuracy, a dynamic threshold selection method of spatial–temporal correlation analysis is proposed for identification criteria. The feasibility and applicability of this method has been verified in the simulation data of IEEE 39 bus system and PMU measured data of the practical power grid. [ABSTRACT FROM AUTHOR]

• The data quality of field PMU measurements is analyzed, the results of which indicate the necessity of data improvement for measurement based potential applications. • A robust state estimation method is adopted to improve the data quality of field PMU measurements for ambient signal based load model parameter identification. • Two scenarios, i.e., data recovery and data correction are considered for the effectiveness verification of the state estimation method for data improvement. • Case studies with not only simulation data from power system analysis toolbox, but also the field PMU measurements from China southern power grid, demonstrate the effectiveness of the state estimation method on data improvement for ambient signal based load model parameter identification. Considering the component based modeling approach's shortage of requiring the typical load model parameters and the traditional measurement based modeling approach's inadequacy of the dependence on fault-disturbance data, the recently proposed ambient signal based load modeling approach offers an important idea to track the time-varying characteristics of power loads. However, it suffers the impacts of phasor measurement unit (PMU) measurement errors. Consequently, data improvement for ambient signal based load modeling is both important and necessary. In this paper, state estimation is adopted to make the ambient signal based method usable with field PMU measurements. To be specific, a weighted least square method is applied for state estimation to improve the data quality. On this basis, the improved data are used for load model parameter identification to evaluate the performance of the state estimation method from the perspective of data application. Case studies with both simulation data from power system analysis toolbox and field PMU measurements from China southern power grid have verified the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes the design procedures and the construction process of a glass fiber reinforced polymer (GFRP) corrugated-core sandwich bridge superstructure. This all-GFRP bridge superstructure was installed in Korea. Based on field load testing and finite element analysis, the effectiveness of the proposed system was demonstrated. The paper also discussed connection details as well as the dynamic effects on the FRP sandwich superstructure due to truck live load. Finally this paper illustrated the time, labor, and cost invested in the project and explained why bridges with FRP superstructures can be economically competitive in the future. [ABSTRACT FROM AUTHOR]

A redox-stable perovskite oxide Sm 0.5 Sr 0.5 FeO 3-δ (SSF) at reduced temperatures is investigated as a new promising electrode material for symmetric solid oxide fuel cells (SSOFCs). SSF exhibits well structural stability and catalytic activity in redox atmosphere at intermediate temperatures (≤750 °C), and the electrical conductivity exhibits a semiconductor behavior both in cathode and anode atmosphere. To enhance the electrochemical performance of SSF by adding oxygen-ion conductor Gd 0.1 Ce 0.9 O 2-δ (GDC), the electrode polarization resistances at 750 °C are reduced from 2.86 to 0.67 Ω cm2 in air and from 4.32 to 0.91 Ω cm2 in humidified H 2 , respectively. Accordingly, the cell performance of SSOFCs with SSF-GDC composite electrode is almost twice (201.74 mW cm−2 at 750 °C) of those with the single-phase one. There preliminary experimental results demonstrate SSF-based electrode materials can be new promising candidates for SSOFCs at low temperatures. [ABSTRACT FROM AUTHOR]

Highly active triple-conducting (proton-, oxygen-ion-, and electron-conducting) perovskite oxide BaCo 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3- δ need to further optimize the electrochemical performance and chemical stability in carbon dioxide and water containing atmospheres, greatly limiting its widespread use in protonic ceramics fuel cells (PCFCs). Here, Ba-site deficient Ba 0.9 Co 0.4 Fe 0.4 Zr 0.1 Y 0.1 O 3- δ (B9CFZY) was synthesized and investigated as a promising candidate concerning the chemical and structural stability, electrical conductivity and electrochemical performance. Anode-supported button cells with the prevalent BaZr 0.1 Ce 0.7 Y 0.2 O 3- δ (BZCY) as electrolyte using B9CFZY and B9CFZY-BZCY cathodes, respectively, were fabricated and then measured at 700-550 °C. The maximum power density of the cells with B9CFZY-based cathodes increase from 452 mW cm−2 to 537 mW cm−2 at 700 °C, however, the corresponding polarization loss decreases from 0.30 to 0.15 Ω cm2 by adding proton-conducting BZCY. Importantly, to better explore the reasons for the improved electrochemical performance, the distribution function of relaxation time (DRT) is used to distinguish different electrode polarization processes of both cells. The results indicate the polarization peaks (P3) of cells with composite cathode resulting from oxygen gas adsorption and dissociation can be greatly accelerated as well as the polarization peaks (P2) resulting from oxygen species diffusion to three phase boundaries or active sites in the cathode. The dramatic improvements demonstrate Ba deficient B9CFZY-BZCY material can be a very competitive cathode material for PCFCs. [ABSTRACT FROM AUTHOR]

In view of the high catalytic activity, enhanced oxygen-ion transport and good stability, the self-assembled hybrid electrocatalyst can be used for symmetrical and reversible solid oxide cells (RSOCs). Herein, a new Ni-free ceramic fuel electrode can be obtained by in situ annealing the orthorhombic perovskite Pr 0.6 Sr 0.4 FeO 3-δ (PSF) in H 2 at 850 °C for 2 h, consisting of orthorhombic perovskite matrix with nano Ruddlesden–Popper oxide (RP/O-PSF). Symmetrical RSOCs consisting of RP/O-PSF fuel electrode, La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3-δ (LSGM) electrolyte and PSF air electrode (PSF|LSGM|PSF) were fabricated and the electrochemical performance was evaluated. The maximum power density of the cell under solid oxide fuel cell (SOFC) mode is 591 mW/cm2 at 800 °C, and the current density of the cell under solid oxide electrolysis cell (SOEC) mode is -1388 mA/cm2 at 800 °C with an applied electrolysis voltage of 1.6 V. The polarization resistances of cell under SOFC mode and SOEC mode are 0.152 Ω cm2 (OCV-0.2 V) and 0.126 Ω cm2 (OCV + 0.2 V), respectively, demonstrating an excellent catalytic activity of RP/O-PSF towards the water electrolysis process compared with hydrogen oxidation reaction (HOR) owing to the accelerated transfer rate of oxygen ions. In addition, the desirable long-term stability indicates the fact that RP/O-PSF hybrid electrode is such a suitable and prospective candidate for symmetrical and reversible solid oxide cells. [ABSTRACT FROM AUTHOR]

As a promising electrocatalyst for hydrogen evolution reaction (HER), molybdenum disulfide (MoS 2) owns inadequate edge active sites and inferior conductivity which restricts its effective application. In this study, the expanded graphite matrix (EGM) cathode was fabricated by tableting worm-like expanded graphite (EG), acetylene black and poly tetra fluoroethylene (PTFE) emulsion, and MoS 2 grew on EGM via a hydrothermal synthesis process, subsequently employed for the HER process. Benefiting from the superior conductivity and sufficient exposure of edge active sites on the rough structure of EGM, MoS 2 /EGM exhibits a small overpotential of 230 mV (j = 10 mA cm−2), a low Tafel slope of 77 mV·dec−1 and a lower value of charge transfer resistance (R ct , 0.919 Ω cm2). The improvement of HER performance of MoS 2 /EGM could be due to the participation of the EGM as a highly conductive substrate. Excellent electrochemical durability of MoS 2 /EGM was attested by the cyclic voltammetry and the amperometric (i − t) measurements. This work may have the potential to develop a promising path to design advanced electrode materials for HER. • MoS 2 /EGM cathode composites were easily synthesized by a hydrothermal method. • The MoS 2 /EGM catalyst shows an excellent HER performance. • MoS 2 and EGM have a synergistic effect in HER at the full pH environments. • The superior HER property of MoS2/EGM is due to conductivity of EGM and uniform growth of MoS2. [ABSTRACT FROM AUTHOR]