Anomalous PL Brightening Inside A Current Density Filament In n-GaAs Under A Pulsed Electric Field

2007 ◽  
Author(s):  
Kazunori Aoki ◽  
Naozumi Sakamoto ◽  
Takayuki Tanigawa
Keyword(s):  
Electric Field ◽  
Current Density ◽  
Pulsed Electric Field ◽  
A Current

scholarly journals Eradication of Saccharomyces cerevisiae by Pulsed Electric Field Treatments

2020 ◽  
Vol 8 (11) ◽  
pp. 1684
Author(s):  
Efrat Emanuel ◽  
Irina Dubrovin ◽  
Ester Hanya ◽  
Gad A. Pinhasi ◽  
Roman Pogreb ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Electric Field ◽  
Current Density ◽  
Food Industry ◽  
Treatment Cycle ◽  
Combined Treatment ◽  
Pulsed Electric Field ◽  
Recovery Processes ◽  
Membrane Resealing ◽  
Phosphate Buffered Saline

One of the promising technologies that can inactivate microorganisms without heat is pulsed electric field (PEF) treatment. The aim of this study was to examine the influence of PEF treatment (2.9 kV cm−1, 100 Hz, 5000 pulses in trains mode of 500 pulses with a pulse duration of 10 µs) on Saccharomyces cerevisiae eradication and resealing in different conditions, such as current density (which is influenced by the medium conductivity), the sort of medium (phosphate buffered saline (PBS) vs. yeast malt broth (YMB) and a combined treatment of PEF with the addition of preservatives. When the S. cerevisiae were suspended in PBS, increasing the current density from 0.02 to 3.3 A cm−2 (corresponding to a total specific energy of 22.04 to 614.59 kJ kg−1) led to an increase of S. cerevisiae eradication. At 3.3 A cm−2, a total S. cerevisiae eradication was observed. However, when the S. cerevisiae in PBS was treated with the highest current density of 3.3 A cm−2, followed by dilution in a rich YMB medium, a phenomenon of cell membrane resealing was observed by flow cytometry (FCM) and CFU analysis. The viability of S. cerevisiae was also examined when the culture was exposed to repeating PEF treatments (up to four cycles) with and without the addition of preservatives. This experiment was performed when the S. cerevisiae were suspended in YMB containing tartaric acid (pH 3.4) and ethanol to a final concentration of 10% (v/v), which mimics wine. It was shown that one PEF treatment cycle led to a reduction of 1.35 log10, compared to 2.24 log10 when four cycles were applied. However, no synergic effect was observed when the preservatives, free SO2, and sorbic acid were added. This study shows the important and necessary knowledge about yeast eradication and membrane recovery processes after PEF treatment, in particular for application in the liquid food industry.

scholarly journals Ammonia removal from fertilizer plant effluents by a coupled electrostatic shielding based electrodialysis / electrodeionization process

2013 ◽  
Vol 14 (4) ◽  
pp. 468-476
Keyword(s):  
Electric Field ◽  
Ammonium Nitrate ◽  
Current Density ◽  
Pure Water ◽  
Nitrate Solution ◽  
Ionic Current ◽  
Ammonia Removal ◽  
Fertilizer Plant ◽  
Ammonium Nitrate Solution ◽  
A Current

Electrically and ionically conducting graphite powder beds interposed between the anode and cathode inside an electrolytic setup are used as intermediate bipolar electrodes. The beds cause electric field discontinuity by eliminating the applied electric field locally within their mass and act as electrostatically shielded zones – ion and ionic current sinks and thus ion concentrating compartments, whereas the adjacent compartments become ion depleting compartments. The ion sinks were implemented in a coupled electrostatic shielding electrodialysis/electrodeionization process to remove ammonium nitrate from fertilizer plant wastewaters. The batch wise operated electrostatic shielding electrodialysis of a solution containing 1310 mg L-1 ammonium nitrate produced in 28 min at a current density of 15-30 A m-2 a concentrate ammonium nitrate solution which could be recycled to the fertilizer plant unit and a diluate containing 50 mg L-1 ammonium nitrate. The diluate was subsequently used as feed in the electrostatic shielding electrodeionization process to produce pure water of a NH4 + and NO3- ion concentration of less than 1 mg L-1 respectively with a flow rate of 5.51x10-4 dm3 s-1 and a current density of 50 A m-2.

scholarly journals Fouling Mitigation by Optimizing Flow Rate and Pulsed Electric Field during Bipolar Membrane Electroacidification of Caseinate Solution

Membranes ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 534
Author(s):  
Vladlen S. Nichka ◽  
Victor V. Nikonenko ◽  
Laurent Bazinet
Keyword(s):  
Electric Field ◽  
Flow Rate ◽  
Current Density ◽  
Pulsed Electric Field ◽  
Pause Duration ◽  
High Flow ◽  
Constant Current ◽  
Bipolar Membrane ◽  
Bipolar Membranes ◽  
Protein Fouling

The efficiency of separation processes using ion exchange membranes (IEMs), especially in the food industry, is significantly limited by the fouling phenomenon, which is the process of the attachment and growth of certain species on the surface and inside the membrane. Pulsed electric field (PEF) mode, which consists in the application of constant current density pulses during a fixed time (Ton) alternated with pause lapses (Toff), has a positive antifouling impact. The aim of this study was to investigate the combined effect of three different relatively high flow rates of feed solution (corresponding to Reynolds numbers of 187, 374 and 560) and various pulse–pause ratios of PEF current regime on protein fouling kinetics during electrodialysis with bipolar membranes (EDBM) of a model caseinate solution. Four different pulse/pause regimes (with Ton/Toff ratios equal to 10 s/10 s, 10 s/20 s, 10 s/33 s and 10 s/50 s) during electrodialysis (ED) treatment were evaluated at a current density of 5 mA/cm2. It was found that increasing the pause duration and caseinate solution flow rate had a positive impact on the minimization of protein fouling occurring on the cationic surface of the bipolar membrane (BPM) during the EDBM. Both a long pause and high flow rate contribute to a more effective decrease in the concentration of protons and caseinate anions at the BPM surface: a very good membrane performance was achieved with 50 s of pause duration of PEF and a flow rate corresponding to Re = 374. A further increase in PEF pause duration (above 50 s) or flow rate (above Re = 374) did not lead to a significant decrease in the amount of fouling.

Effect of Parameters of Pulsed Electric Field on Average Current Density through Nafion 438 Membrane in Electrodialysis Cell

2018 ◽  
Vol 54 (10) ◽  
pp. 775-781 ◽  
Author(s):  
S. V. Zyryanova ◽  
D. Yu. Butyl’skii ◽  
S. A. Mareev ◽  
N. D. Pis’menskaya ◽  
V. V. Nikonenko ◽  
...  
Keyword(s):  
Electric Field ◽  
Current Density ◽  
Pulsed Electric Field ◽  
Average Current Density ◽  
Electrodialysis Cell ◽  
Average Current

Degradation of the Acousto-Electric Current Saturation Behavior in C-Axis Fiber-Textured Polycrystalline Zinc Oxide Films

1996 ◽  
Vol 426 ◽  
Author(s):  
T. Pompe ◽  
V. Srikant ◽  
D. R. Clarke
Keyword(s):  
Zinc Oxide ◽  
Electric Field ◽  
Grain Boundaries ◽  
Electric Current ◽  
Current Density ◽  
Oxide Films ◽  
Constant Field ◽  
Zinc Oxide Films ◽  
Current Saturation ◽  
A Current

AbstractAcousto-electric current saturation has been observed in thin, polycrystalline Al-doped zinc oxide films grown on fused quartz. The films, grown by laser ablation, are c-axis textured with high angle grain boundaries between the grains. After annealing at 600°C in 0.1 mtorr oxygen, the films exhibit a current saturation at a current density of 2 105 A/cm2 and electric fields of 5 103 V/cm. However, under constant field the current density falls and the current saturation behavior is not maintained. Current saturation at the same current density can, however, be restored by increasing the electric field. Similarly, the appearance and disappearance of the current saturation behavior can be reversibly controlled by annealing in different oxygen partial pressures at 200°C. The degradation phenomena is attributed to the high acoustic flux enhancing the diffusion of oxygen along the grain boundaries where oxygen can alter the grain boundary potential barrier and hence the electric field in the grains.

scholarly journals Mathematical Modeling of the Effect of Pulsed Electric Field on the Specific Permselectivity of Ion-Exchange Membranes

Membranes ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 115
Author(s):  
Andrey Gorobchenko ◽  
Semyon Mareev ◽  
Victor Nikonenko
Keyword(s):  
Mathematical Model ◽  
Electric Field ◽  
Current Density ◽  
Mass Transfer Rate ◽  
Pulsed Electric Field ◽  
Concentration Profiles ◽  
Average Current Density ◽  
Diffusion Layers ◽  
Specific Permeability ◽  
Average Current

The application of pulsed electric field (PEF) in electrodialysis has been proven to be efficient for a number of effects: increasing mass transfer rate, mitigation of scaling and fouling, reducing water splitting. Recently, the improvement of the membrane permselectivity for specific counterions was discovered experimentally by the group of Laurent Bazinet (N. Lemay et al. J. Memb. Sci. 604, 117878 (2020)). To better understanding the effect of PEF in electrodialysis, simulations were performed using a non-stationary mathematical model based on the Nernst–Planck and Poisson equations. For the first time, it was not only the condition used when the current density is specified but also the condition when the voltage is set. A membrane and two adjacent diffusion layers are considered. It is shown that when applying the regime used by Lemay et al. (the same current density in conventional continuous current (CC) mode and during the pulses in PEF mode), there is a significant gain in specific permselectivity. It is explained by a reduction in the membrane concentration polarization in PEF mode. In the CC mode of electrodialysis, increasing current density leads to a loss in specific permselectivity: concentration profiles in the diffusion layers and membrane are formed in such a way that ion diffusion reduces the migration flux of the preferentially transferred ion and increases that of the poorly transferred ion. In PEF mode, the concentration profiles are partially restored during the pauses when the current is zero. However, if a different condition is used than the condition applied by Lemay et al., that is, when the same average current density is applied in both the PEF and CC modes, there is no gain in specific permeability. It is shown that within the framework of the applied mathematical model, the specific selectivity depends only on the average current density and does not depend on the mode of its application (CC or PEF mode).

Facet Topography and Dislocation Structure as a Possible Source for Electrical Heterogeneity in [001] TILT Bicrystals of YBa2Cu3O7-δ

1996 ◽  
Vol 54 ◽  
pp. 338-339
Author(s):  
I-Fei Tsu ◽  
D.L. Kaiser ◽  
S.E. Babcock
Keyword(s):  
Grain Boundary ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Electromagnetic Properties ◽  
Length Scale ◽  
Density Values ◽  
Current Densities ◽  
Applied Fields ◽  
A Current

A current theme in the study of the critical current density behavior of YBa2Cu3O7-δ (YBCO) grain boundaries is that their electromagnetic properties are heterogeneous on various length scales ranging from 10s of microns to ˜ 1 Å. Recently, combined electromagnetic and TEM studies on four flux-grown bicrystals have demonstrated a direct correlation between the length scale of the boundaries’ saw-tooth facet configurations and the apparent length scale of the electrical heterogeneity. In that work, enhanced critical current densities are observed at applied fields where the facet period is commensurate with the spacing of the Abrikosov flux vortices which must be pinned if higher critical current density values are recorded. To understand the microstructural origin of the flux pinning, the grain boundary topography and grain boundary dislocation (GBD) network structure of [001] tilt YBCO bicrystals were studied by TEM and HRTEM.

A highly stable CoMo2S4/Ni3S2 heterojunction electrocatalyst for efficient hydrogen evolution

2021 ◽  
Author(s):  
Minmin Wang ◽  
Mengke Zhang ◽  
Wenwu Song ◽  
Weiting Zhong ◽  
Xunyue Wang ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Current Density ◽  
A Current

A CoMo2S4/Ni3S2 heterojunction is prepared with an overpotential of only 51 mV to drive a current density of 10 mA cm−2 in 1 M KOH solution and ∼100% of the potential remains in the ∼50 h chronopotentiometric curve at 10 mA cm−2.

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