scholarly journals Behavior of Microorganisms from Wastewater Treatments in Extremely Low-Frequency Electric Field

2021 ◽  
Vol 12 (4) ◽  
pp. 5071-5080
Keyword(s):  
Wastewater Treatment ◽  
Field Strength ◽  
Electric Field ◽  
Activated Sludge ◽  
Electric Field Strength ◽  
Electric Fields ◽  
Dielectric Spectroscopy ◽  
Low Frequency ◽  
Domestic Wastewater ◽  
Extremely Low Frequency

The paper presents the research results regarding the metabolism of microorganisms from domestic wastewater treatment-activated sludge. The research approached this issue by dielectric spectroscopy measurements, chemical analyses, and specific microbiological techniques. In addition, the influence of extremely low-frequency (ELF) electric fields (1÷500 Hz) on microbial metabolism was studied. Four representative frequencies have been identified: 49.9, 99.9, 130.8, and 150.4 Hz using dielectric spectroscopy applied to the investigated samples. Also, dielectric loss and conductivity evolutions showed significant discontinuities, indicating oscillation/resonance phenomena in the investigated biomass, unlike the sterilized sludge samples (obtained either by boiling or electrically, applying a voltage that creates a 100 V/m electric field strength on the sample), which did not show discontinuities; instead, the values of tgδ and σ were approx. 5-6 times larger. Chemical and microbiological tests have shown that the metabolism, growth, and multiplication of microorganisms in activated sludge are significantly increased after exposure to 4-6 V/m electric field strength of 50 Hz. The research may continue by developing equipment and a bioelectrotechnological process to significantly increase the efficiency of wastewater treatment plants.

scholarly journals Photoluminescence of CdSe/ZnS quantum dots in nematic liquid crystals in electric fields

2018 ◽  
Vol 9 ◽  
pp. 1544-1549 ◽  
Author(s):  
Margarita A Kurochkina ◽  
Elena A Konshina ◽  
Daria Khmelevskaia
Keyword(s):  
Quantum Dots ◽  
Liquid Crystals ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Electric Fields ◽  
Dielectric Anisotropy ◽  
Vertical Position ◽  
Decay Times ◽  
Pl Intensity

We have experimentally investigated the effect of the reorientation of a nematic liquid crystal (LC) in an electric field on the photoluminescence (PL) of CdSe/ZnS semiconductor quantum dots (QDs). To the LC with positive dielectric anisotropy, 1 wt % QDs with a core diameter of 5 nm was added. We compared the change of PL intensity and decay times of QDs in LC cells with initially planar or vertically orientated molecules, i.e., in active or passive LC matrices. The PL intensity of the QDs increases four-fold in the active LC matrix and only 1.6-fold in the passive LC matrix without reorientation of the LC molecules. With increasing electric field strength, the quenching of QDs luminescence occurred in the active LC matrix, while the PL intensity did not change in the passive LC matrix. The change in the decay time with increasing electric field strength was similar to the behavior of the PL intensity. The observed buildup in the QDs luminescence can be associated with the transfer of energy from LC molecules to QDs. In a confocal microscope, we observed the increase of particle size and the redistribution of particles in the active LC matrix with the change of the electric field strength. At the same time, no significant changes occurred in the passive LC matrix. With the reorientation of LC molecules from the planar in vertical position in the LC active matrix, quenching of QD luminescence and an increase of the ion current took place simultaneously. The obtained results are interesting for controlling the PL intensity of semiconductor QDs in liquid crystals by the application of electric fields.

Das toroidale schwachionisierte Magnetoplasma I

1967 ◽  
Vol 22 (12) ◽  
pp. 1890-1903
Author(s):  
F. Karger
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Electric Fields ◽  
Transverse Electric ◽  
Refined Theory ◽  
Toroidal Plasma ◽  
Dc Discharge ◽  
Transverse Electric Fields

In a previous paper31 discrepancies between theory and experiment were found on investigating the positive column in a curved magnetic field. The approximation derived in 31 for the torus drift in a weakly ionized magnetoplasma is therefore checked here (Part I) with a refined theory which also yields the transverse electric field strength. Experimentally, both the transverse electric fields and the density profiles in the DC discharge were determined in addition to the longitudinal electric field strength.The discrepancies occurring in 31 are ascribed to the fact that the plasma concentrates at the cathode end of the magnetic field coils, this effect having a considerable influence on the form of the transverse density profile and on the stability behaviour. Part II later will show how the influence of this concentration can be eliminated and what effect in the current-carrying toroidal plasma causes a marked reduction of the charge carrier losses.

Inactivation of Microorganisms in Cloudy Ginkgo (Ginkgo biloba Linn.) Juice by Pulsed Electric Fields

2007 ◽  
Vol 13 (2) ◽  
pp. 83-90 ◽  
Author(s):  
H. Zhang ◽  
Z. Wang ◽  
R.-J. Yang ◽  
S.-Y. Xu
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Electric Fields ◽  
Treatment Time ◽  
Synergistic Effects ◽  
Pulsed Electric Fields ◽  
Bath Temperature ◽  
Microbial Inactivation ◽  
Plate Counts

Pulsed electric fields (PEF) were applied to neutral ginkgo cloudy juice to study the influence of the electric field strength, the treatment time and temperature on microbial inactivation. The results showed that microbial inactivation increased with the electric field strength, the treatment time and temperature. PEF treatment caused 3.39 and 4.44-log cycles reduction of coliforms and total plate counts, respectively, when pulse duration was 3 μs, the electric field strength 30 kV/cm, the treatment time 520 μs and the water bath temperature 15°C. Under the same conditions, the microbial shelf life of ginkgo cloudy juice was extended to 24 days at 4°C and 18 days at room temperature. A 3.7-log cycles reduction of the total yeast and mould counts was obtained by applying 390 μs of 30 kV/cm at 15°C.Yeast and mould cells were less resistant to PEF process than bacteria cells. The effect of heat generated during the PEF treatment was limited on microbial inactivation. Temperature and the induced heat by PEF had synergistic effects to microbial inactivation in cloudy ginkgo juice.

Effect of Electric Field Strength on Texture Evolution of IF Steel Sheet during Annealing

2012 ◽  
Vol 706-709 ◽  
pp. 2617-2621
Author(s):  
Chang Shu He ◽  
Xiang Zhao ◽  
Wei Ping Tong ◽  
Liang Zuo
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Electric Fields ◽  
Applied Electric Field ◽  
Steel Sheet ◽  
Texture Evolution ◽  
If Steel ◽  
X Ray Diffraction ◽  
If Steel Sheet

Specimens cut from a cold-rolled IF steel sheet of 1 mm thickness were respectively annealed at 750°C for 20min under a range of DC electric fields (1kV/cm~4kV/cm). The Effect of electric field strength on recrystallization texture of IF steel sheet was studied by mean of X-ray diffraction ODF analysis. It was found that γ-fiber textures were notably enhanced as electric field strength increased. The strength of γ-fiber textures got their peak values as the applied electric field reached to 4kV/cm. The possible reason for such phenomena was discussed in the viewpoint of interaction between the applied electric field and the orientation-dependent stored-energy in deformed metals which is known as the driving force for recrystallization during annealing.

Electrokinetic Instability Flow in Nanofilm-Coated Microfluidic Channels

2009 ◽  
Vol 60-61 ◽  
pp. 330-333
Author(s):  
Wei Chih Chen ◽  
Ting Fu Hong ◽  
Wen Bo Luo ◽  
Chang Hsien Tai ◽  
Chien Hsiung Tsai ◽  
...  
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Electric Fields ◽  
Flow Instability ◽  
Microfluidic Channels ◽  
Conductivity Ratio ◽  
Electrokinetic Instability ◽  
Two Samples ◽  
Significant Difference

This paper presented a parametric experimental study of electrokinetic instability phenomena in a cross-shaped configuration microfluidic device with varying channel depths and conductivity ratios. The flow instability is observed when applied electric field strength exceeds a certain critical value. The critical electric field strength is examined as a function of the conductivity ratio of two samples liquid, microchannel depth, and the treatment of microchannel wetted surface. It is found that the critical electric field strengths for the onset of electrokinetic instability are strongly dependent on the conductivity ratio of two samples liquid, and decrease as the channel depths increasing of microfluidic devices. In the present study, the surface inside microchannels is treated utilizing hydrophilic and hydrophobic organic-based SOG (spin-on-glass) nanofilms for glass-based microchips. The experimental results indicate that no significant difference for the critical electric fields for the onset of electrokinetic instability phenomena in both hydrophilic and hydrophobic SOG coating in the surface of microchannels. The critical electric fields for the onset of electrokinetic instability phenomena are slightly lower in both SOG coated cases in compare with that of the non-coated microchannel.

scholarly journals Weak rTMS-induced electric fields produce neural entrainment in humans

2019 ◽  
Author(s):  
Elina Zmeykina ◽  
Matthias Mittner ◽  
Walter Paulus ◽  
Zsolt Turi
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Electric Fields ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Current Standard ◽  
Conventional Dose ◽  
Novel Approach ◽  
Resting Motor Threshold ◽  
Field Strengths

Repetitive transcranial magnetic stimulation (rTMS) is a potent tool for modulating endogenous oscillations in humans. The current standard dosing method for rTMS defines the electric field strength only indirectly. A better characterization of the electric field strength induced by a given rTMS protocol is necessary in order to improve the understanding of the neural mechanisms of rTMS. In this study we used a novel approach, in which individualized prospective computational modeling of the induced electric field guided the choice of stimulation intensity. We consistently found that rhythmic rTMS protocols increased neural synchronization in the posterior alpha frequency band when measured simultaneously with scalp electroencephalography. We observed this effect already at electric field strengths of roughly half the lowest conventional dose, which is 80% of the resting motor threshold. We conclude that rTMS can induce immediate electrophysiological effects at much weaker electric field strengths than previously thought.

scholarly journals Comparative Modeling of Transcranial Magnetic and Electric Stimulation in Mouse, Monkey, and Human

2018 ◽  
Author(s):  
Ivan Alekseichuk ◽  
Kathleen Mantell ◽  
Sina Shirinpour ◽  
Alexander Opitz
Keyword(s):  
Finite Element ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Electric Fields ◽  
Mouse Brain ◽  
Electric Stimulation ◽  
Human Model ◽  
Brain Anatomy ◽  
List Type

ABSTRACTTranscranial magnetic stimulation (TMS) and transcranial electric stimulation (TES) are increasingly popular methods to noninvasively affect brain activity. However, their mechanism of action and dose-response characteristics remain under active investigation. Translational studies in animals play a pivotal role in these efforts due to a larger neuroscientific toolset enabled by invasive recordings. In order to translate knowledge gained in animal studies to humans, it is crucial to generate comparable stimulation conditions with respect to the induced electric field in the brain. Here, we conduct a finite element method (FEM) modeling study of TMS and TES electric fields in a mouse, capuchin monkey, and human model. We systematically evaluate the induced electric fields and analyze their relationship to head and brain anatomy. We find that with increasing head size, TMS-induced electric field strength first increases and then decreases according to a two-term exponential function. TES-induced electric field strength strongly decreases from smaller to larger specimen with up to 100x fold differences across species. Our results can serve as a basis to compare and match stimulation parameters across studies in animals and humans.HIGHLIGHTSTranslational research in brain stimulation should account for large differences in induced electric fields in different organismsWe simulate TMS and TES electric fields using anatomically realistic finite element models in three species: mouse, monkey, and humanTMS with a 70 mm figure-8 coil creates an approximately 2-times weaker electric field in a mouse brain than in monkey and human brains, where electric field strength is comparableTwo-electrode TES creates an approximately 100-times stronger electric field in a mouse brain and 3.5-times stronger electric field in a monkey brain than in a human brain

scholarly journals Identifying regions in prefrontal cortex related to working memory improvement: a novel meta-analytic method using electric field modeling

2021 ◽  
Author(s):  
Miles Wischnewski ◽  
Kathleen E. Mantell ◽  
Alexander Opitz
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Electric Fields ◽  
Brain Regions ◽  
Medium Effect ◽  
Analytic Method ◽  
List Type

AbstractAltering cortical activity using transcranial direct current stimulation (tDCS) has been shown to improve working memory (WM) performance. Due to large inter-experimental variability in the tDCS montage configuration and strength of induced electric fields, results have been mixed. Here, we present a novel meta-analytic method relating behavioral effect sizes to electric field strength to identify brain regions underlying largest tDCS-induced WM improvement. Simulations on 69 studies targeting left prefrontal cortex showed that tDCS electric field strength in lower dorsolateral prefrontal cortex (Brodmann area 45/47) relates most strongly to improved WM performance. This region explained 7.8% of variance, equaling a medium effect. A similar region was identified when correlating WM performance and electric field strength of right prefrontal tDCS studies (n = 18). Maximum electric field strength of five previously used tDCS configurations were outside of this location. We thus propose a new tDCS montage which maximizes the tDCS electric field strength in that brain region. Our findings can benefit future tDCS studies that aim to affect WM function.Highlights-We summarize the effect of 87 tDCS studies on working memory performance-We introduce a new meta-analytic method correlating tDCS electric fields and performance-tDCS-induced electric fields in lower DLPFC correlate significantly with improved working memory-The lower DLPFC was not maximally targeted by most tDCS montages and we provide an optimized montage

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