Effects of tensile stress on electrochemical characteristics and structural morphology of P110SS steels in carbon dioxide-saturated solution

A high-temperature autoclave was used to grow CO2 corrosion-product films on P110SS steel specimens while the surface of the specimens was continuously subjected to tensile stress in a four-point bending jig; the autoclaving times were 6, 18, 36, and 72 h. A scanning electron microscope was used to observe the surface topography of the corrosion-product films formed on the P110SS steels. An X-ray diffraction was used to analyze the phase compositions of the corrosion products. The electrochemical performance of the films was investigated using electrochemical impedance spectroscopy and potentiodynamic polarization curves. The results showed that tensile stress could hinder the formation of corrosion-product films; the integrity and compactness of the films worsened, but the phase compositions of the films did not change. The applied tensile stress resulted in a smaller grain size of the corrosion-product films, and the grain boundaries increased. In addition, owing to the induced tensile stress, the charge transfer resistances decreased, and the corrosion current densities increased for the P110SS steels with corrosion-product films in a 3.5 wt.% NaCl solution saturated with CO2.

DC characterization of advanced fine-filamentary MgB2 superconducting wires.

MgB2 wires with 114, 192 and 342 filaments of size 14-19 µm manufactured by HyperTech Research, Inc. have been subjected to low temperature DC measurements. R(T), I-V characteristics, critical currents and stress and strain tolerances of these wires differing by filament architecture and filament size sheathed by resistive CuNi alloys were measured and compared with the literature data. It was found that these fine-filamentary wires have high engineering current densities not reduced by twisting up to 10 mm, sufficient strain tolerances and therefore are promising for future applications where minimised AC losses are required due resistive sheaths, thin MgB2 filaments and short twist pitches.

Visualisation and quantification of flooding phenomena in gas diffusion electrodes (GDEs) used for electrochemical CO2 reduction: A combined EDX/ICP–MS approach

The most promising strategy to up-scale the electrochemical CO2 reduction reaction (ec-CO2RR) is based on the use of gas diffusion electrodes (GDEs) that allow current densities close to the range of 1 A/cm2 to be reached. At such high current densities, however, the flooding of the GDE cathode is often observed in CO2 electrolysers. Flooding hinders the access of CO2 to the catalyst, and by thus leaving space for (unwanted) hydrogen evolution, it usually leads to a decrease of the observable Faradaic efficiency of CO2 reduction products. To avoid flooding as much as possible has thus become one of the most important aims of to-date ec-CO2RR engineering, and robust analytical methods that can quantitatively assess flooding are now in demand. As flooding is very closely related to the formation of carbonate salts within the GDE structure, in this paper we use alkali (in particular, potassium) carbonates as a tracer of flooding. We present a novel analytical approach —based on the combination of cross-sectional energy-dispersive X-ray (EDX) mapping and inductively coupled plasma mass spectrometry (ICP--MS) analysis— that can not only visualise, but can also quantitatively describe the electrolysis time dependent flooding in GDEs, leading to a better understanding of electrolyser malfunctions.

Alcohols electrooxidation coupled with H2 production at high current densities promoted by a cooperative catalyst

Electrochemical alcohols oxidation offers a promising approach to produce valuable chemicals and facilitate coupled H2 production. However, the corresponding current density is very low at moderate cell potential that substantially limits the overall productivity. Here we report the electrooxidation of benzyl alcohol coupled with H2 production at high current density (540 mA cm−2 at 1.5 V vs. RHE) over a cooperative catalyst of Au nanoparticles supported on cobalt oxyhydroxide nanosheets (Au/CoOOH). The absolute current can further reach 4.8 A at 2.0 V in a more realistic two-electrode membrane-free flow electrolyzer. Experimental combined with theoretical results indicate that the benzyl alcohol can be enriched at Au/CoOOH interface and oxidized by the electrophilic oxygen species (OH*) generated on CoOOH, leading to higher activity than pure Au. Based on the finding that the catalyst can be reversibly oxidized/reduced at anodic potential/open circuit, we design an intermittent potential (IP) strategy for long-term alcohol electrooxidation that achieves high current density (>250 mA cm−2) over 24 h with promoted productivity and decreased energy consumption.

Newton’s Third Law in the Framework of Special Relativity for Charged Bodies Part 2: Preliminary Analysis of a Nano Relativistic Motor

(1) Background: In a recent paper discussing Newton’s third law in the framework of special relativity for charged bodies, it was suggested that one can construct a practical relativistic motor provided high enough charge and current densities are available. As on the macroscopic scale charge density is limited by the phenomena of dielectric breakdown, it was suggested to take advantage of the high charge densities which are available on the microscopic scale. (2) Methods: We use standard physical theories such as Maxwell electrodynamics and quantum mechanics, supplemented by tools from vector analysis and numerics. (3) Results: We show that a hydrogen atom either in the ground state or excited state will not produce a relativistic engine effect, but by breaking the symmetry or putting the electron in a wave packet state may produce relativistic motor effect. (4) Conclusions: A highly localized wave packet will produce a strong relativistic motor effect. The preliminary analysis of the current paper suggests new promising directions of research both theoretical and experimental.

Electrical Discharges in Oil-Lubricated Rolling Contacts and Their Detection Using Electrostatic Sensing Technique

The reliability of rolling element bearings has been substantially undermined by the presence of parasitic and stray currents. Electrical discharges can occur between the raceway and the rolling elements and it has been previously shown that these discharges at relatively high current density levels can result in fluting and corrugation damages. Recent publications have shown that for a bearing operating at specific mechanical conditions (load, temperature, speed, and slip), electrical discharges at low current densities (<1 mA/mm2) may substantially reduce bearing life due to the formation of white etching cracks (WECs) in bearing components, often in junction with lubricants. To date, limited studies have been conducted to understand the electrical discharges at relatively low current densities (<1 mA/mm2), partially due to the lack of robust techniques for in-situ quantification of discharges. This study, using voltage measurement and electrostatic sensors, investigates discharges in an oil-lubricated steel-steel rolling contact on a TE74 twin-roller machine under a wide range of electrical and mechanical conditions. The results show that the discharges events between the rollers are influenced by temperature, load, and speed due to changes in the lubricant film thickness and contact area, and the sensors are effective in detecting, characterizing and quantifying the discharges. Hence, these sensors can be effectively used to study the influence of discharges on WEC formation.

Analysis of electrical characteristics and electroluminescent efficiency of field induced contact-DGOLET

This research paper discusses the significance development in field-induced contact dual-gate organic light emitting transistor (FIC-DGOLET) device architecture and characteristics. The device behaviour is analyzed and observed significant value of electroluminescent efficiency. The deep investigation of FIC-DGOLET device is discussed in this paper, where impact of varying the various parameters such as thickness of organic semiconductor (OSC) materials from the range of 400 nm to 200 nm at altered value of threshold voltage by using 2D ATLAS simulator. Its theoretical calculation influence over the dynamic control of the device characteristics such as saturated drain current (I ds ), mobility (μ), threshold voltage (V th ) as well as sub threshold swing. The FIC-DGOLET is a dual-gate transistor which also emits light by the operations of two accumulated regions, that are electrons and holes which is not completely overlapped to each other. The leakage current in DG-OLET can be reduced to the extent that 70% than single gate OLET (SG-OLET). The recombination zone mechanism of FIC-DGOLET plays a vital role in its performance, where we get comparable value of electroluminescent efficiency with reported, low value of exciton quenching and current densities. The extracted parameters of DG-OLETs are like drive current of 100A, I on/off 108, threshold voltage V th of 1.3 V at V gs of –3 V and V ds of 0 to –3 V. These extracted performance parameters are very helpful in designing of flexible display applications.

A Novel Indium-Induced-Synthesis In0.17Ru0.83O2 Nanoribbon as Highly Active Electrocatalysts for Oxygen Evolution in Acidic Media at High Current Densities above 400 mA cm−2

Ruthenium dioxide-based electrocatalyst possesses the most potential in acidic oxygen evolution reaction (OER), however, most of them show low current density, low mass activity and unsatisfied stability under strong acidic...