Tris-bipyridine iron (II) triflate was synthesized and used as an active species to demonstrate a symmetric disproportionation redox-flow-battery chemistry that works without supporting electrolyte. Solutions of this coordination complex salt (0.1 M in acetonitrile), which the cation provides redox activity, were qualitatively characterized with cyclic voltammetry perform extended full-cell charge/discharge cycling impedance testing reactors containing porous Daramic 175 separator membrane....

Abstract Corrosion fatigue crack growth rates were obtained for an ASTM A 471 Ni-Cr-Mo-V turbine disc steel tested in a room temperature 12M NaOH solution. Tests conducted under open circuit and applied potentials. The range of potentials was −530 to −1280 mVn, which includes the passive, active peak, circuit, cathodic regimes. For tests at frequency 1 Hz, R ratio equal 0.5 sinusoidal waveform, maximum environmental effect order magnitude increase rate lowest potential. This decreased as...

Abstract Corrosion fatigue crack growth studies have been conducted on a Ni-Cr-Mo-V turbine disc steel in saturated sodium chloride and sulfate environments at 100C. The results show that rate is accelerated both the open circuit potential, compared to air environment. Crack further with application of large cathodic potential. Anodic potential has no effect relative circiut Cracking occurred transgranularly around intergranularly under severe charging conditions. amount intergranular...

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Vanadium acetylacetonate (V(acac)3) disproportionation electrochemistry promises a crossover-tolerant, high-voltage flow battery, but exhibits low efficiency and short cycle life. We show that membrane fouling, rather than parasitic side reaction, dominates early performance fade. Crossover rates through porous membranes were estimated from voltage transients with an adaptive observer while cycling flow-through reactors. For 0.1M V(acac)3 0.3M TEABF4 in acetonitrile flowed countercurrently...

Due to their unique advantages in terms of long cycle life and modular design, redox flow batteries (RFBs) are being developed load-level peak shave energy from intermittent sources such as wind sunlight. RFBs have yet meet the stringent cost requirements needed achieve broad market penetration, however. The second largest associated with state-of-the art after electrolyte itself is ion-exchange membrane, which accounts for 30% total cell [1]. Porous separators provide a pathway...

The increasing drive for enhanced electrochemical energy storage underscores the importance of understanding and predicting concentrated electrolyte transport behavior. most popular frameworks ion in electrolytes are Stefan-Maxwell Onsager frameworks. Stefan–Maxwell equations relate potential’s gradient terms flux driving forces [1]. On other hand, framework inverts this to species thermodynamic [2]. Both thermodynamically consistent, but each requires different properties which often...

Among various battery systems, redox flow batteries (RFBs) have been shown to be a particularly promising technology for large-scale stationary energy storage applications due their unique advantages in terms of long cycle life and modular design. RFBs, however, are significantly different from conventional operating principle, while many engineering aspects carried over similar systems such as fuel cells. This study explores field design, commonly overlooked practical aspect batteries,...

Abstract— A first‐generation fatigue crack growth model has been developed which realistically models the patterns of subsurface shells and detail fracture that are commonly observed in railroad rails. (These types defects further described Introduction.) The key assumptions upon is based reviewed input data on rail residual stresses wheel‐induced described. Examples predicted for fractures shown compared to actually patterns. Apparent deficiencies discussed probable avenues improvement...

Abstract— A fatigue analysis was conducted on a rail that placed in the Facility for Accelerated Service Testing (FAST) after detail fracture detected service. The initial crack produced service grown to failure under controlled FAST conditions simulating Knowledge of wheel/rail load history this made it an ideal candidate quantitative growth analysis. investigation revealed undulations surface were caused by changes direction traffic. angle facture surface, with respect running rail,...

Abstract A computerized database, EPRI Database on Environmentally Assisted Cracking (EDEAC), has been established to assemble stress-corrosion cracking and corrosion fatigue crack growth data materials of interest the nuclear power generation industry. The database is currently being used review basis for existing ASME reference curves low alloy ferritic steels reactor pressure vessels. Also, correlations between rate stress intensity factor range with corrections frequency, ratio,...

Vanadium acetylacetonate (V(acac)3) disproportionation electrochemistry promises a crossover-tolerant, high-voltage flow battery, but exhibits low efficiency and short cycle life. We show that membrane fouling, rather than parasitic side reaction, dominates early performance fade. Crossover rates through porous membranes were estimated from voltage transients with an adaptive observer while cycling flow-through reactors. For 0.1 M V(acac)3 0.3 TEABF4 in acetonitrile flowed countercurrently...

Abstract Corrosion fatigue crack growth studies have been conducted on a Ni-Cr-Mo-V turbine disc steel in saturated sodium chloride and sulphate environments at 100 C. The results show that rate is accelerated both the open circuit potential compared to air environment. Crack further with application of large cathodic potential. Anodic has no effect circuite Cracking occurred transgranularly around intergranularly under severe charging conditions. amount intergranular cracking increased...