Ideal Gas Reference for Association and Dissociation Reactions: II. Kinetic Reference Potentials and Concentration Bias in Electrolysis

The ideal gas reference for association and dissociation reactions, developed in the first part of this series, is applied to electrochemical reactions. We obtain an ideal Nernst equation that quantifies the unspecific voltage contribution arising from an imbalance between the reactant and product concentrations of an electrochemical reaction for the given conditions. Subtracting this concentration bias from the equilibrium voltage/potential, we define the "kinetic reference voltage/potential" where the reactant and product states are "aligned" within the potential energy landscape of the system. The kinetic reference voltage/potential is a fundamental descriptor for a given electrochemical reaction, providing an intrinsic reference point which is most relevant in cases where the (standard) equilibrium voltage/potential is biased by large concentration differences between the reactant and product side. This is most dramatic for the case of water electrolysis, where the gaseous H₂ and O₂ product concentrations are several orders of magnitude smaller than the liquid water reactant concentration. The respective equilibrium voltage is strongly biased by the low H₂ and O₂ concentrations, although the latter do not directly influence the forward water splitting rate. The unbiased kinetic reference voltage agrees remarkably well with the experimentally observed onset of macroscopic water splitting rates. We further extend our analysis to the kinetic reference potentials of the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and lattice oxygen evolution reaction (LOER), providing an unconventional perspective on pH-dependent overpotentials, anticipated electrocatalysis improvements, and kinetic stabilization of electrocatalyst materials.

Understanding the Crucial Significance of the Temperature and Potential Window on the Stability of Carbon Supported Pt-alloy Nanoparticles as Oxygen Reduction Reaction Electrocatalysts

The present research provides a comprehensive study of carbon-supported intermetallic Pt-alloy electrocatalysts and assesses their stability against metal dissolution in relation to the operating temperature and the potential window using two advanced electrochemical methodologies: (i) the in-house designed high-temperature disk electrode (HT-DE) methodology as well as (ii) a modification of the electrochemical flow cell coupled to an inductively coupled plasma mass spectrometer (EFC-ICP-MS), allowing for highly sensitive time- and potential-resolved measurements of metal dissolution. The findings contradict the generally accepted hypothesis that in contrast to the rate of carbon corrosion, which follows the Arrhenius law and increases exponentially with temperature, the kinetics of Pt and subsequently the less noble metal dissolution are supposed to be for the most part unaffected by temperature. On the contrary, clear evidence is presented that in addition to the importance of the voltage/potential window, the temperature is one of the most critical parameters governing the stability of Pt and thus, in the case of Pt-alloy electrocatalysts also the ability of the nanoparticles (NPs) to retain the less noble metal. Lastly, but also very importantly, results indicate that the rate of Pt redeposition significantly increases with temperature, which has been the main reason why mechanistic interpretation of the temperature-dependent kinetics related to the stability of Pt remained highly speculative until now.

DIRECT OBSERVATION OF HIGH-TEMPERATURE AREAS OF METAL MELT AT OXYGEN CONVERTER BLOWING WITH LOW VOLTAGE APPLICATION

Introduction. The process of oxygen conversion, despite the existing improvements, can be supplemented by physical methods of influence, including the unconventional method of applying low-voltage potential developed at the Iron and Steel Institute of the NAS of Ukraine.Problem Statement. The studies of the method of low-voltage potential application on 60, 160 and 250 ton converters have shown that the technology intensifies thermophysical and hydrodynamic processes in the gasslag-metal system and increases the converter process efficiency.Purpose. The purpose of this research is to study the features of the influence on the reaction zones of the low voltage potential application at four blowing options with the use of high-temperature physical model.Materials and Methods. A physical model that simulates the top, bottom and combined oxygen blowing under low-voltage potential application of different polarity on the lance has been used. An insert of a transparent quartz plate is made in one of the walls for visual observation and video recording. The top blowing is conductedwith two nozzle lance (nozzle diameter 1.7 mm with an angle of 30 ° to the lance). The bottom blowing is conducted with a bottom tuyere with a 1.5 mm diameter central nozzle. Combined blowing is realized by a combination ofthese options.Results. The visual observation of the reaction zones with different blowing options has shown that the highest temperature and the largest dimensions of the brightest parts of the bath correspond to the combined blowing, while the lowest ones are reported for the bottom blowing. While applying the low-voltage potential method it has been established that the reaction zone is longer at the positive polarity on the lance, during the period of silicon oxidation, and at the negative polarity on the lance, during the period of intense carbon oxidation. The video of gas bubbles flotation, probably CO, has shown that the bubbles are formed more intensively in thecase of negative polarity on the lance.Conclusions. The applied technique has allowed estimating the influence of low-voltage potential application on the geometric parameters of the reaction zone.

Aerial Robotics: State-based Conflict Detection and Resolution (Detect and Avoid) in High Traffic Densities and Complexities

Purpose of Review A lot of research into decentralised, state-based conflict detection and resolution, or detect and avoid algorithms has been executed. This paper explains the essential properties of state-based conflict detection and reviews the work in the context of applications for not only manned but also unmanned aerial vehicles, where this might be applied relatively soon. Recent Findings Lately, based on several reviews of a variety of published algorithms, a selection has been implemented and simulated in extremely high traffic densities for comparison. Summary The modified voltage potential has been surprisingly efficient, even compared with more complex algorithms or adaptations, as is apparent from looking at macroscopic metrics like domino effect, efficiency and safety. This indicates that to this date, it is so far the most suitable algorithm for the detect and avoid role for unmanned aerial vehicles in urban airspaces, or other areas where a high density is expected.

Stability of current density impedance imaging II

<p style='text-indent:20px;'>This paper is a continuation of the authors earlier work on stability of Current Density Impedance Imaging (CDII) [R. Lopez, A. Moradifam, Stability of Current Density Impedance Imaging, SIAM J. Math. Anal. (2020).] We show that CDII is stable with respect to errors in both measurement of the magnitude of the current density vector field in the interior and the measurement of the voltage potential on the boundary. This completes the authors study of the stability of Current Density Independence Imaging which was previously shown only by numerical simulations.</p>

Novel investigation of perovskite membrane based electrochemical nitric oxide control phenomenon

The combustion of hydrocarbon fuels within the automotive industry results in harmful and reactive incomplete combustion byproducts. Specifically, nitric oxide emissions (NO) lead to increased smog, acid rain, climate change, and respiratory inflammation within the population [Nitrogen Dioxide | American Lung Association]. Current methods for treating combustion exhaust include the catalytic converter in conjunction with nitrogen oxide traps. However, there is no active, continuous reduction method that does not require restrictions on the combustion environment (Hirata in Catal Surv Asia 18:128–133, 2014). Here, a small voltage potential oscillation across a newly designed electro-chemical catalytic membrane significantly reduces NO emissions. A ceramic membrane consisting of two dissimilar metal electrodes, sandwiching a dielectric layer, is able to achieve an NO reduction in excess of 2X that of a platinum group metal (PGM) three way catalytic converter. An analysis of the exhaust effluent from the membranes indicates N2O as a precursor to N2 and O2 formation, without the introduction of ammonia (NH3), during the reaction of NO indicating a divergence from current literature. Our results demonstrate how an oscillatory electric potential on a catalytic surface may alter anticipated reaction chemistry and interaction between the catalytic surface and fluid flow.

“Stress Control Optimization using Particle Swarm Optimization Algorithm”

Confined field upgrade, particularly in the zone near the high voltage potential and ground potential will quicken the corruption and in this way causing pre-developed disappointment of the protecting material. Other than electrical field upgrade, mechanical stresses and natural impacts additionally influence the presentation of the high voltage overhead separators. Therefore, multi-feature approaches are required to improve the HV separators execution and unwavering quality over their administration life. In the subsequent segment, the current pressure control techniques that incorporate crown ring, consolidated protection get together and end-fitting plan are checked on.