Wire Electrochemical Etching of Superhydrophobic 304 Stainless Steel Surfaces Based on High Local Current Density with Neutral Electrolyte

In a PEM fuel cell, local current density can vary drastically under the land and channel areas. The non-uniform current density distribution not only affects the overall performance of the fuel cell, but also leads to the local temperature and concentration differentiation on the MEA, which can cause problems such as membrane dehydration and catalyst degradations at certain locations. In order to investigate the local current performance, the objective of this work is to directly measure the local current density variations across the land and channel at the cathode in a PEM fuel cell with partially-catalyzed MEAs. First, the cathode flow plate is specially designed with a single-serpentine channel structure, and the gas diffusion electrode at cathode side is cut to fit this flow field size (5.0cm×1.3cm). Then five different partially-catalyzed MEAs with 1mm width corresponding to different locations from the middle of the gas channel to the middle of the land area are made. Fuel cells with each of the partially-catalyzed MEAs have been tested and the results provide the lateral current density distribution across the channel and the land areas. In the high cell voltage region, local current density is highest under the center of the land area and decreases toward the center of the channel area; while in the low cell voltage region local current density is highest under the middle of the channel area and decrease toward the center of the land area. Different flow rates are tested at the cathode side of the cell to study their effects on the local current density performance along the land-channel direction. And the results show that the flow rate barely has the effect on the current at the high cell voltage region, while it plays a significant role at the low voltage region due to the mass transport effect.

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Erratum: “Local current density measurement using a Rogowski probe in the Tokyo Spherical Tokamak-2” [Rev. Sci. Instrum. 85, 11D813 (2014)]

Review of Scientific Instruments ◽

10.1063/1.4898800 ◽

2014 ◽

Vol 85 (11) ◽

pp. 11F903 ◽

Cited By ~ 1

Author(s):

H. Furui ◽

Y. Nagashima ◽

Y. Takase ◽

A. Ejiri ◽

H. Kakuda ◽

...

Keyword(s):

Current Density ◽

Density Measurement ◽

Spherical Tokamak ◽

Local Current Density ◽

Local Current

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Antibacterial properties of Magainin II peptide onto 304 stainless steel surfaces: A comparison study of two dopamine modification methods

Colloids and Surfaces B Biointerfaces ◽

10.1016/j.colsurfb.2020.111198 ◽

2020 ◽

Vol 194 ◽

pp. 111198

Author(s):

Pan Cao ◽

Kewei Liu ◽

Xiaodan Liu ◽

Wei Sun ◽

Duoli Wu ◽

...

Keyword(s):

Stainless Steel ◽

Antibacterial Properties ◽

304 Stainless Steel ◽

Comparison Study ◽

Steel Surfaces ◽

Magainin Ii

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Effects of NiSO4 Concentration on the Coloring Performance and Corrosion Resistance of the Colored Film on 304 Stainless Steel

Coatings ◽

10.3390/coatings10060598 ◽

2020 ◽

Vol 10 (6) ◽

pp. 598

Author(s):

Wenwei Li ◽

Jun-e Qu ◽

Zhiyong Cao ◽

Hairen Wang

Keyword(s):

Stainless Steel ◽

Wear Resistance ◽

Corrosion Resistance ◽

Electrochemical Impedance Spectroscopy ◽

Electrochemical Impedance ◽

Negative Impact ◽

304 Stainless Steel ◽

Nacl Solution ◽

Time Curve ◽

Steel Surfaces

The colored films were successfully prepared on the 304 stainless steel surfaces in coloring solutions with different NiSO4 contents. The purpose of this study was to investigate the effects of NiSO4 in the coloring solution on the coloring performance of 304 stainless steel and corrosion resistance of the obtained colored film in NaCl solution. The coloring rate was determined from coloring potential-time curve, and the protection properties of the color films in a 3.5% NaCl solution were characterized by potentiodynamic polarization scan, electrochemical impedance spectroscopy, and wear resistance test. The results showed that adding NiSO4 could accelerate the coloring process but brought about a negative impact on the surface’s corrosion resistance.

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First current density measurements in the ring current region using simultaneous multi-spacecraft CLUSTER-FGM data

Annales Geophysicae ◽

10.5194/angeo-23-1849-2005 ◽

2005 ◽

Vol 23 (5) ◽

pp. 1849-1865 ◽

Cited By ~ 53

Author(s):

C. Vallat ◽

I. Dandouras ◽

M. Dunlop ◽

A. Balogh ◽

E. Lucek ◽

...

Keyword(s):

Magnetic Field ◽

Current Density ◽

Ring Current ◽

Magnetic Activity ◽

Activity Level ◽

Local Current Density ◽

Magnetospheric Configuration And Dynamics ◽

Local Current ◽

Current Region ◽

First Time

Abstract. The inner magnetosphere's current mapping is one of the key elements for current loop closure inside the entire magnetosphere. A method for directly computing the current is the multi-spacecraft curlometer technique, which is based on the application of Maxwell-Ampère's law. This requires the use of four-point magnetic field high resolution measurements. The FGM experiment on board the four Cluster spacecraft allows, for the first time, an instantaneous calculation of the magnetic field gradients and thus a measurement of the local current density. This technique requires, however, a careful study concerning all the factors that can affect the accuracy of the J estimate, such as the tetrahedral geometry of the four spacecraft, or the size and orientation of the current structure sampled. The first part of this paper is thus providing a detailed analysis of the method accuracy, and points out the limitations of this technique in the region of interest. The second part is an analysis of the ring current region, which reveals, for the first time, the large latitudinal extent of the ring current, for all magnetic activity levels, as well as the latitudinal evolution of the perpendicular (and parallel) components of the current along the diffuse auroral zone. Our analysis also points out the sharp transition between two distinct plasma regions, with the existence of high diamagnetic currents at the interface, as well as the filamentation of the current inside the inner plasma sheet. A statistical study over multiple perigee passes of Cluster (at about 4 RE from the Earth) reveals the azimuthal extent of the partial ring current. It also reveals that, at these distances and all along the evening sector, there isn't necessarily a strong dependence of the local current density value on the magnetic activity level. This is a direct consequence of the ring current morphology evolution, as well as the relative positioning of the spacecraft with respect to the bulk of the ring current. It also proves the existence of a substantial ring current at these distances, all over the evening and the post-midnight sector. Keywords. Magnetospheric physics (Current systems; Energetic particles, trapped; Magnetospheric configuration and dynamics)

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Nanoengineered Superhydrophobic Surfaces to Prevent Adhesion of Listeria monocytogenes for Improved Food Safety

Transactions of the ASABE ◽

10.13031/trans.13934 ◽

2020 ◽

Vol 63 (5) ◽

pp. 1401-1407

Author(s):

Bog Eum Lee ◽

Youngsang You ◽

Won Choi ◽

Eun-mi Hong ◽

Marisa M. Wall ◽

...

Keyword(s):

Stainless Steel ◽

Listeria Monocytogenes ◽

Biofilm Formation ◽

Electrochemical Etching ◽

Contact Angles ◽

Bacterial Attachment ◽

Superhydrophobic Surfaces ◽

List Type ◽

Ptfe Film ◽

Steel Surfaces

HighlightsNanoporous superhydrophobic surfaces were fabricated using electrochemical etching and Teflon coating.Adhesion of Listeria monocytogenes to the nanoengineered stainless steel surfaces was reduced.Self-cleanable food-contact surfaces prevent bacterial attachment and subsequent biofilm formation.Abstract. Bacterial attachment on solid surfaces and subsequent biofilm formation is a significant problem in the food industry. Superhydrophobic surfaces have potential to prevent bacterial adhesion by minimizing the contact area between bacterial cells and the surface. In this study, stainless steel-based superhydrophobic surfaces were fabricated by manipulating nanostructures with electrochemical etching and polytetrafluoroethylene (PTFE) film. The formation of nanostructures on stainless steel surfaces was characterized by field emission scanning electron microscopy (FESEM). The stainless steel surfaces etched at 10 V for 5 min and at 10 V for 10 min with PTFE deposition resulted in average water contact angles of 154° ±4° with pore diameters of 50 nm. In addition, adhesion of Listeria monocytogenes was decreased by up to 99% compared to the bare substrate. These findings demonstrate the potential for the development of antibacterial surfaces by combining nanoporous patterns with PTFE films. Keywords: Electrochemical etching, PTFE, Nanoengineered surface, L. monocytogenes, Superhydrophobic.

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Ladderlike carbon nanoarrays on 3D conducting skeletons enable uniform lithium nucleation for stable lithium metal anodes

Chemical Communications ◽

10.1039/c8cc02672f ◽

2018 ◽

Vol 54 (42) ◽

pp. 5330-5333 ◽

Cited By ~ 22

Author(s):

Lin Liu ◽

Ya-Xia Yin ◽

Jin-Yi Li ◽

Yu-Guo Guo ◽

Li-Jun Wan

Keyword(s):

Current Density ◽

Ion Flux ◽

Lithium Metal ◽

Local Current Density ◽

Local Current ◽

Lithium Metal Anodes ◽

Li Ion ◽

Metal Anodes ◽

Nucleation Growth

Well-arranged ladderlike carbon nanoarrays can bring about homogenous Li-ion flux and reduced local current density, thus regulating uniform Li nucleation/growth.

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