scholarly journals The spectrum of carbon arcs in air at high current densities

1927 ◽  
Vol 117 (776) ◽  
pp. 164-182 ◽  
Keyword(s):  
Current Density ◽  
High Current Density ◽  
Short Note ◽  
Direct Vision ◽  
Ground Glass ◽  
Total Radiation ◽  
High Current ◽  
Carbon Arc ◽  
Current Densities ◽  
Made In

Although the spectrum of the ordinary carbon arc has been studied in great detail during the last 70 years, there seems to have been no similar study of the “High Current Density” arc which was introduced by Beck in 1914. Spectrophotometrical measurements have been made in connection with the development of this type of arc for searchlights, and photographs of the spectra obtained from the total radiation from the arc have been published. The only account, however, of the spectrum from individual parts of the arc appears in a short note by Bell and Bassett. They examined an image of the arc on a ground glass screen with a direct vision spectroscope and reported that in the arc stream 15 lines appeared when the current exceeded 100 amperes. They attributed 7 of these to helium and 2 to hydrogen.

scholarly journals Unexpected Genomic Features of High Current Density-Producing Geobacter sulfurreducens strain YM18

2021 ◽  
Author(s):  
Takashi Fujikawa ◽  
Yoshitoshi Ogura ◽  
Koki Ishigami ◽  
Yoshihiro Kawano ◽  
Miyuki Nagamine ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Current Density ◽  
Iron Reduction ◽  
High Current Density ◽  
Model Organism ◽  
Geobacter Sulfurreducens ◽  
Extracellular Electron Transfer ◽  
High Current ◽  
Current Production ◽  
Current Densities

Abstract Geobacter sulfurreducens produces high current densities and it has been used as a model organism for extracellular electron transfer studies. Nine G. sulfurreducens strains were isolated from biofilms formed on an anode poised at –0.2 V (vs. SHE) in a bioelectrochemical system in which river sediment was used as an inoculum. The maximum current density of an isolate, strain YM18 (9.29 A/m2), was higher than that of the strains PCA (5.72 A/m2), the type strain of G. sulfurreducens, and comparable to strain KN400 (8.38 A/m2), which is another high current producing strain of G. sulfurreducens. Genomic comparison of strains PCA, KN400, and YM18 revealed that omcB, xapD, spc, and ompJ, which are known to be important genes for iron reduction and current production in PCA, were not present in YM18. In the PCA and KN400 genomes, two and one region (s) encoding CRISPR/Cas systems were identified, respectively, but they were missing in the YM18 genome. These results indicate that there is genetic variation in the key components involved in extracellular electron transfer among G. sulfurreducens strains.

Selective Conversion of Carbon Dioxide to Formate with High Current Densities

2021 ◽  
pp. 2150001
Author(s):  
Xiulin Yang ◽  
Defei Liu ◽  
Shenghong Zhong ◽  
Xiaofeng Zhou ◽  
Kuo-Wei Huang ◽  
...  
Keyword(s):  
Current Density ◽  
Hollow Fiber ◽  
Active Sites ◽  
Large Scale ◽  
High Current Density ◽  
High Current ◽  
Faradaic Efficiency ◽  
Practical Applications ◽  
Selective Conversion ◽  
Current Densities

Selective conversion of CO2 to formate with high current densities is highly desirable but still challenging. Copper hollow fibers with interconnected pore structures were fabricated via a facile method and used as a stand-alone cathode for highly efficient electrochemical reduction of CO2 to formate. Our studies revealed that delivering the reactant CO2 gas to the inner space of the hollow fiber could build up a higher CO2 partial pressure in the pores and presumably reduce the concentration of H[Formula: see text] from the electrolyte to effectively suppress the major competing reaction, hydrogen evolution reaction (HER), from 46.9% faradaic efficiency (FE) to 15.0%. A high selectivity for CO2 reduction to formate with a maximum FE of 77.1% was achieved with a high current density of 34.7[Formula: see text]mA cm[Formula: see text], which is one of the highest FEs on Cu-based materials. Mechanistic studies suggest that the abundant active sites along with the unique crystal facets induced by the high pressure of CO2 at the pore surface in the “gas in” mode are attributed to the superior electroactivity and selectivity for the CO2 reduction to formate. The Cu hollow fiber electrodes exhibit an outstanding long-term stability at high current density, showing great potential for large-scale practical applications.

Layer-structured FeCo bihydroxide as an ultra-stable bifunctional electrocatalyst for water splitting at high current densities

2021 ◽  
Author(s):  
Chaoyang Sun ◽  
Hui Wang ◽  
Shan Ji ◽  
Xuyun Wang ◽  
Vladimir Linkov ◽  
...  
Keyword(s):  
Water Splitting ◽  
Current Density ◽  
High Stability ◽  
High Current Density ◽  
High Current ◽  
Bifunctional Electrocatalyst ◽  
Current Densities ◽  
Double Hydroxide

A layered FeCo double hydroxide bifunctional water cracking electrocatalyst with ultra-high stability at high current density was developed.

Stable high current density operation of La0.6Sr0.4Co0.2Fe0.8O3−δ oxygen electrodes

2019 ◽  
Vol 7 (22) ◽  
pp. 13531-13539 ◽  
Author(s):  
Matthew Y. Lu ◽  
Justin G. Railsback ◽  
Hongqian Wang ◽  
Qinyuan Liu ◽  
Yvonne A. Chart ◽  
...  
Keyword(s):  
High Temperatures ◽  
Current Density ◽  
High Current Density ◽  
Solid Oxide ◽  
Stable Operation ◽  
Electrochemical Cells ◽  
High Current ◽  
Oxygen Electrodes ◽  
Current Densities

Stable operation of LSCF oxygen electrodes with high current densities at high temperatures for solid oxide electrochemical cells.

Effect of Current Density on Microstructure of Mn-Cu Thin Films via Electroplating Coating Technique

2013 ◽  
Vol 829 ◽  
pp. 451-455 ◽  
Author(s):  
Maryam Haeri far ◽  
Morteza Zandrahimi
Keyword(s):  
Current Density ◽  
High Current Density ◽  
304 Stainless Steel ◽  
Crystallographic Structure ◽  
High Current ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cu Alloy ◽  
Current Densities ◽  
Amorphous Coatings

In the present study 304 stainless steel (SS) was electrochemical plated with nanocrystallineMn-Cu alloy coatings from a bath containing ammonium sulfate.The electrochemical investigation of Mn-Cu electrodeposited films was managed by potentiodynamic scans and galvanostatic experiments. The effect of current density on the microstructure, crystallographic structure, and chemical composition of the deposits were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive x-ray spectrometry (EDS), respectively.The results showed that Mn-Cu coatings obtained at low current density contain a large amount of Cu and heterogeneous microstructure, while at high current density uniform, compact, and amorphous coatings with a small amount of Cu was obtained. The results indicated that Cu co-deposition delayed the phase transformation of as-deposited ductile γ-Mn to the brittle and hard α-Mn. However, the results did not show any specific changes in grain size of the coatings with variation of current densities.

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

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Zhenhua Li ◽  
Yifan Yan ◽  
Si-Min Xu ◽  
Hua Zhou ◽  
Ming Xu ◽  
...  
Keyword(s):  
Benzyl Alcohol ◽  
Current Density ◽  
High Current Density ◽  
H2 Production ◽  
Open Circuit ◽  
High Current ◽  
Cell Potential ◽  
Current Densities ◽  
Electrode Membrane

AbstractElectrochemical 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.

Evaporative Cooling of High Current Density Mini-Lenses

1976 ◽  
Vol 34 ◽  
pp. 536-537 ◽  
Author(s):  
N. W. Parker ◽  
M. Utlaut ◽  
A. V. Crewe
Keyword(s):  
Reynolds Number ◽  
High Resolution ◽  
Water Flow ◽  
Current Density ◽  
Temperature Rise ◽  
Cooling System ◽  
High Current Density ◽  
Evaporative Cooling ◽  
High Current ◽  
Current Densities

Mulvey has described microscope lenses which are considerably smaller than conventional lenses due to the higher current densities which he can achieve by using a more efficient cooling system. There are some difficulties associated with this type of lens, however, which make it potentially difficult to use in high resolution microscopes. First of all, the velocity of water flow is necessarily high in order to provide the cooling required (0.5 Watts/cm2) , making the Reynolds number high and turbulence inevitable. Such turbulence produces vibration. Secondly, the temperature rise is high so that one cannot easily avoid increasing the temperature of the column which can lead to outgassing and subsequent specimen contamination.

High Current Density Superconducting Magnets Using Heavy Currents

1971 ◽  
Vol 49 (1) ◽  
pp. 155-156 ◽  
Author(s):  
D. L. Atherton
Keyword(s):  
Current Density ◽  
High Current Density ◽  
Superconducting Magnets ◽  
Rate Sensitivity ◽  
High Current ◽  
Inside Diameter ◽  
Charge Rate ◽  
Current Densities

This note reports on three 5 cm inside diameter superconducting magnets generating 66 kG at 1250 A, 64 kG at 1360 A, and 56 kG at 1890 A, with current densities of 27 200 A/cm2, 30 500 A/cm2, and 42 000 A/cm2, respectively. Fine filamentary conductors are used. Charge rate sensitivity is reported.

Surface Characteristics and Hydrophilicity of the as-Anodized Films Formed at High Current Density on Ti-6Al-4V in Different Electrolytes

2014 ◽  
Vol 608 ◽  
pp. 274-279 ◽  
Author(s):  
Phanawan Whangdee ◽  
Sutthima Sriprasertsuk ◽  
Viritpon Srimaneepong ◽  
Dujreutai Pongkao Kashima
Keyword(s):  
Current Density ◽  
High Current Density ◽  
High Surface ◽  
Film Surface ◽  
Surface Characteristics ◽  
Adsorbed Water ◽  
High Current ◽  
Water Contact ◽  
Galvanostatic Method ◽  
Current Densities

Hydrophilicity of the as-anodized films is an important factor for improving the osseointegration of Ti implants and bone tissues. This study investigated the surface characteristics and the hydrophilicity of the as-anodized films formed on Ti-6Al-4V. The as-anodized films on Ti-6Al-4V were prepared using galvanostatic method in 1M H3PO4 or 1M MCPM as an electrolyte with different current densities (5, 20, 80 mA/cm2) and using potentiostatic method with different voltages (5, 100 and 150 V) for 30 minute at room temperature. The as-anodized films shows a significantly lower water contact angle compared to the untreated Ti-6Al-4V. The porous oxide films were fabricated on Ti-6Al-4V. Ti 2p spectra show that the as anodized films consist of TiO2 and O 1s present hydroxide (OH-) and adsorbed water (H2O) that effect to the hydrophilicity on the as-anodized film surface. These results demonstrate that the galvanostatic method at a high current density of 20 mA/cm2 and the potentiostatic at a high voltage of 150 V in MCPM could enhance both of the high surface roughness and appropriate surface species which is leading to good hydrophilicity on the as-anodized films.

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