scholarly journals Droplets generation conducting during laser-plasma treating of metals in electric field

2021 ◽  
Vol 2064 (1) ◽  
pp. 012097
Author(s):  
A Yu Ivanov ◽  
A L Sitkevich ◽  
S V Vasil’ev
Keyword(s):  
Laser Radiation ◽  
Field Strength ◽  
Electric Field ◽  
External Electric Field ◽  
Short Circuit ◽  
Characteristic Size ◽  
Electric Breakdown ◽  
Laser Plume ◽  
Initial Stage ◽  
The Mean

Abstract Evolution of plasma plume generation on the surface of metal irradiated by laser beam with the mean radiation flux density ~ 106 W/cm2 in the external electric field with different polarity and field strength from 0 to 106 V/m was experimentally investigated. It is shown that the mean size of metal droplets carried out from the irradiated zone of target becomes materially (in several times) smaller when of the external electric field strength amplitude grow, independently to its polarity. It is essential that the mentioned differences (at the considered parameters of laser radiation) are observed only at the initial stage of the laser plume development, because after the steam-plasma cloud reaches the electrode an electric breakdown (short-circuit) occurs, and the external field in the interelectrode gap disappears. Electric breakdown leads to the spasmodic increase of electron density and temperature of plasma and to effective absorption of laser radiation by plasma torch (shielding of the target). In consequence of shielding droplets generation happens only during electric field existence. This explains decrease by several times of the characteristic size of the target substance droplets in spite of short duration of electric field existence.

scholarly journals Investigating the feasibility of cerebellar transcranial direct current stimulation to facilitate post-stroke overground gait performance in chronic stroke: a partial least-squares regression approach

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Dhaval Solanki ◽  
Zeynab Rezaee ◽  
Anirban Dutta ◽  
Uttama Lahiri
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Chronic Stroke ◽  
Least Squares Regression ◽  
Significance Level ◽  
Gait Performance ◽  
Wilcoxon Rank Sum Test ◽  
Gait Parameters ◽  
The Mean

Abstract Background Investigation of lobule-specific electric field effects of cerebellar transcranial direct current stimulation (ctDCS) on overground gait performance has not been performed, so this study aimed to investigate the feasibility of two lobule-specific bilateral ctDCS montages to facilitate overground walking in chronic stroke. Methods Ten chronic post-stroke male subjects participated in this repeated-measure single-blind crossover study, where we evaluated the single-session effects of two bilateral ctDCS montages that applied 2 mA via 3.14 cm2 disc electrodes for 15 min targeting (a) dentate nuclei (also, anterior and posterior lobes), and (b) lower-limb representations (lobules VIIb-IX). A two-sided Wilcoxon rank-sum test was performed at a 5% significance level on the percent normalized change measures in the overground gait performance. Partial least squares regression (PLSR) analysis was performed on the quantitative gait parameters as response variables to the mean lobular electric field strength as the predictors. Clinical assessments were performed with the Ten-Meter walk test (TMWT), Timed Up & Go (TUG), and the Berg Balance Scale based on minimal clinically important differences (MCID). Results The ctDCS montage specific effect was found significant using a two-sided Wilcoxon rank-sum test at a 5% significance level for 'Step Time Affected Leg' (p = 0.0257) and '%Stance Time Unaffected Leg' (p = 0.0376). The changes in the quantitative gait parameters were found to be correlated to the mean electric field strength in the lobules based on PLSR analysis (R2 statistic = 0.6574). Here, the mean electric field strength at the cerebellar lobules, Vermis VIIIb, Ipsi-lesional IX, Vermis IX, Ipsi-lesional X, had the most loading and were positively related to the 'Step Time Affected Leg' and '%Stance Time Unaffected Leg,' and negatively related to the '%Swing Time Unaffected Leg,' '%Single Support Time Affected Leg.' Clinical assessments found similar improvement in the TMWT (MCID: 0.10 m/s), TUG (MCID: 8 s), and BBS score (MCID: 12.5 points) for both the ctDCS montages. Conclusion Our feasibility study found an association between the lobular mean electric field strength and the changes in the quantitative gait parameters following a single ctDCS session in chronic stroke. Both the ctDCS montages improved the clinical outcome measures that should be investigated with a larger sample size for clinical validation. Trial registration: Being retrospectively registered.

Electrostatic Forces on Particles Floating Within the Interface Between Two Immiscible Fluids

2007 ◽  
Author(s):  
Nadine Aubry ◽  
Pushpendra Singh
Keyword(s):  
Dielectric Properties ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
External Electric Field ◽  
Capillary Force ◽  
Electrostatic Force ◽  
Immiscible Fluids ◽  
Electrostatic Forces ◽  
Dipole Interactions

The objective of this paper is to study the dependence of the electrostatic force that act on a particle within the interface between two immiscible fluids on the parameters such as the dielectric properties of the fluids and particles, the particle’s position within the interface, and the electric field strength. It is shown that the component of electrostatic force normal to the interface varies as a2, where a is the particle radius, and since in equilibrium it is balanced by the vertical capillary force, the interfacial deformation caused by the particle changes when an external electric field is applied. In addition, there are lateral electrostatic forces among the particles due to the dipole-dipole interactions which, when the distance between two particles is O(a), vary as a2, and remain significant for submicron sized particles.

scholarly journals Study into Dynamics of Structural Changes Occurring in Blood Plasma under Laser Radiation

2021 ◽  
Vol 7 (1) ◽  
pp. 010302
Author(s):  
Anna Neupokoeva ◽  
Dmitry Gavrilov ◽  
Andrey Yakutin
Keyword(s):  
Laser Radiation ◽  
Blood Plasma ◽  
Structural Changes ◽  
Characteristic Size ◽  
Human Blood Plasma ◽  
Plasma Exposure ◽  
Speckle Patterns ◽  
The Mean ◽  
The Impact ◽  
532 Nm

This paper focuses on studying the impact of laser irradiation ( = 532 nm, power 15 mW) on human blood plasma. The structural changes in plasma were controlled by the crystallographic method with the mean crystallogram segment size as a numerical evaluation. In addition, the structural changes were explored by processing the speckle patterns obtained during laser radiation passes through plasma. Exposure to laser radiation of  = 532 nm for 20 min resulted in the 30% reduced the crystallogram characteristic size with the dynamics of the structural changes coinciding with the dynamics discovered by speckle patterns processing. The crystallographic method revealed that laser induced structural changes in plasma remain for 24–36 h after exposure.

scholarly journals Investigating the Feasibility of Cerebellar Transcranial Direct Current Stimulation to facilitate Post-Stroke Overground Gait Performance in Chronic Stroke: a partial least-squares regression approach

2020 ◽  
Author(s):  
Dhaval Solanki ◽  
Zeynab Rezaee ◽  
Anirban Dutta ◽  
Uttama Lahiri
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Least Squares Regression ◽  
Significance Level ◽  
Gait Performance ◽  
Post Stroke ◽  
Wilcoxon Rank Sum Test ◽  
Gait Parameters ◽  
The Mean

Abstract Background: Cerebellar transcranial Direct Current Stimulation (ctDCS) has been shown to be promising as an adjuvant treatment to facilitate post-stroke gait rehabilitation; however, investigation of lobule-specific electric field effects on overground gait performance has not been performed. Methods: Ten chronic post-stroke male subjects participated in this repeated-measure single-blind crossover study, where we evaluated the single-session effects of two bilateral ctDCS montages that applied 2mA via 3.14cm 2 disc electrodes for 15 minutes targeting a) dentate nuclei (also, anterior and posterior lobes), and b) lower-limb representations (lobules VIIb-IX). A two-sided Wilcoxon rank-sum test was performed at 5% significance level on the percent normalized change measures in the overground gait performance. Partial least squares regression (PLSR) analysis was performed on the quantitative gait parameters as response variables to the mean lobular electric field strength as the predictors. Clinical assessments were performed with the Ten-Meter walk test (TMWT), Timed Up & Go (TUG), and the Berg Balance Scale based on minimal clinically important differences (MCID). Results: The ctDCS montage specific effect was found significant using a two-sided Wilcoxon rank-sum test at a 5% significance level for 'Step Time Affected Leg' (p=0.0257) and '%Stance Time Unaffected Leg' (p=0.0376). The changes in the quantitative gait parameters were found to be correlated to the mean electric field strength in the lobules based on PLSR analysis ( R 2 statistic = 0.6574). Here, the mean electric field strength at the cerebellar lobules, Vermis VIIIb, Ipsi-lesional IX, Vermis IX, Ipsi-lesional X, had the most loading, and were positively related to the 'Step Time Affected Leg' and '%Stance Time Unaffected Leg,' and negatively related to the '%Swing Time Unaffected Leg,' '%Single Support Time Affected Leg.' Clinical assessments found similar improvement in the TMWT (MCID: 0.10m/sec), TUG (MCID: 8sec), and BBS score (MCID: 12.5 points) for both the ctDCS montages. Conclusion: Our feasibility study found an association between the lobular mean electric field strength and the changes in the quantitative gait parameters following a single ctDCS session in chronic stroke. Both the ctDCS montages improved the clinical outcome measures that should be investigated with a larger sample size for clinical validation.

scholarly journals Investigating the Feasibility of Cerebellar Transcranial Direct Current Stimulation to facilitate Post-Stroke Overground Gait Performance in Chronic Stroke: a partial least-squares regression approach

2020 ◽  
Author(s):  
Dhaval Solanki ◽  
Zeynab Rezaee ◽  
Anirban Dutta ◽  
Uttama Lahiri
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Chronic Stroke ◽  
Least Squares Regression ◽  
Significance Level ◽  
Gait Performance ◽  
Wilcoxon Rank Sum Test ◽  
Gait Parameters ◽  
The Mean

Abstract Background: Investigation of lobule-specific electric field effects of cerebellar transcranial direct current stimulation (ctDCS) on overground gait performance has not been performed, so this study aimed to investigate the feasibility of two lobule-specific bilateral ctDCS montages to facilitate overground walking in chronic stroke. Methods: Ten chronic post-stroke male subjects participated in this repeated-measure single-blind crossover study, where we evaluated the single-session effects of two bilateral ctDCS montages that applied 2mA via 3.14cm2 disc electrodes for 15 minutes targeting a) dentate nuclei (also, anterior and posterior lobes), and b) lower-limb representations (lobules VIIb-IX). A two-sided Wilcoxon rank-sum test was performed at a 5% significance level on the percent normalized change measures in the overground gait performance. Partial least squares regression (PLSR) analysis was performed on the quantitative gait parameters as response variables to the mean lobular electric field strength as the predictors. Clinical assessments were performed with the Ten-Meter walk test (TMWT), Timed Up & Go (TUG), and the Berg Balance Scale based on minimal clinically important differences (MCID).Results: The ctDCS montage specific effect was found significant using a two-sided Wilcoxon rank-sum test at a 5% significance level for 'Step Time Affected Leg' (p=0.0257) and '%Stance Time Unaffected Leg' (p=0.0376). The changes in the quantitative gait parameters were found to be correlated to the mean electric field strength in the lobules based on PLSR analysis (R2 statistic = 0.6574). Here, the mean electric field strength at the cerebellar lobules, Vermis VIIIb, Ipsi-lesional IX, Vermis IX, Ipsi-lesional X, had the most loading and were positively related to the 'Step Time Affected Leg' and '%Stance Time Unaffected Leg,' and negatively related to the '%Swing Time Unaffected Leg,' '%Single Support Time Affected Leg.' Clinical assessments found similar improvement in the TMWT (MCID: 0.10m/sec), TUG (MCID: 8sec), and BBS score (MCID: 12.5 points) for both the ctDCS montages. Conclusion: Our feasibility study found an association between the lobular mean electric field strength and the changes in the quantitative gait parameters following a single ctDCS session in chronic stroke. Both the ctDCS montages improved the clinical outcome measures that should be investigated with a larger sample size for clinical validation.

Prädissoziation im elektrischen Feld — ein neues Phänomen in der Molekülspektroskopie

1970 ◽  
Vol 25 (3) ◽  
pp. 406-411
Author(s):  
F. J. Comes ◽  
U. Wenning
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Linear Function ◽  
External Electric Field ◽  
Excited States ◽  
Coupling Mechanism ◽  
Molecular Dissociation ◽  
Selection Rules ◽  
Molecular Fields

Molecules in certain excited states can be forced to predissociate in an external electric field. This effect will be shown to occur with H2 and D2. The molecular dissociation is made possible by an altered coupling mechanism as compared to the mechanism considered for the Kronig's selection rules. The interaction is a linear function of the field strength. It is further demonstrated that also molecular fields (van der Waal's fields) may cause the effect which is shown by the collision induced predissociation of the excited molecular states under consideration

Ultralow lattice thermal conductivity and dramatically enhanced thermoelectric properties of monolayer InSe induced by external electric field

2021 ◽  
Author(s):  
Zheng Chang ◽  
Kunpeng Yuan ◽  
Zhehao Sun ◽  
Xiaoliang Zhang ◽  
Yufei Gao ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
External Electric Field ◽  
Thermoelectric Properties ◽  
Electrostatic Interaction ◽  
Lattice Thermal Conductivity ◽  
Phonon Transport ◽  
Thermoelectric Performance

With the ability of altering the inherent interatomic electrostatic interaction, modulating external electric field strength is a promising approach to tune the phonon transport behavior and enhance thermoelectric performance of...

scholarly journals Об ускорении релятивистской частицы импульсом излучения

2019 ◽  
Vol 126 (2) ◽  
pp. 211
Author(s):  
Н.Н. Розанов
Keyword(s):  
Laser Radiation ◽  
Laser Pulse ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Laser Pulses ◽  
Pulse Time ◽  
Dominant Component ◽  
Wide Range ◽  
Mechanical Momentum

AbstractConcerning direct acceleration of charges by pulses of electromagnetic (laser) radiation with arbitrary shapes, we have found a relationship between the components of the mechanical momentum of a relativistic (but not ultrarelativistic) particle. In a wide range of conditions, the energy transferred by the radiation to a particle to be accelerated is determined by the electric area of the laser pulse, i.e., by the integral of the electric field strength over the pulse time. This indicates that it is promising to develop schemes for generation of quasi-unipolar radiation laser pulses, in which the strength of the dominant component of the electric field does not change its sign during the main pulse duration.

scholarly journals Investigating the Effects of Cerebellar Transcranial Direct Current Stimulation on Post-Stroke Overground Gait Performance: A Partial Least-Squares Regression Approach

2020 ◽  
Author(s):  
Dhaval Solanki ◽  
Zeynab Rezaee ◽  
Anirban Dutta ◽  
Uttama Lahiri
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Partial Least Squares Regression ◽  
Least Squares Regression ◽  
Significance Level ◽  
Gait Performance ◽  
Post Stroke ◽  
The Mean

Stroke often results in impaired gait, which can limit community ambulation and the quality of life. Recent works have shown the feasibility of transcranial Direct Current Stimulation (tDCS) as an adjuvant treatment to facilitate gait rehabilitation. Since the cerebellum plays an essential role in balance and movement coordination, which is crucial for independent overground ambulation, so, we investigated the effects of cerebellar tDCS (ctDCS) on the post-stroke overground gait performance in chronic stroke survivors. Fourteen chronic post-stroke male subjects were recruited based on convenience sampling at the collaborating hospitals where ten subjects finally participated in the ctDCS study. We evaluated the effects of two ctDCS montages with 2mA direct current, a) optimized configuration for dentate stimulation with 3.14cm2 disc anode at PO10h (10/5 EEG system) and 3.14cm2 disc cathode at PO9h (10/5 EEG system), and b) optimized configuration for leg lobules VII-IX stimulation with 3.14cm2 disc anode at Exx8 (electrodes defined by ROAST) and 3.14cm2 disc cathode at Exx7. We found ctDCS to be acceptable by all the exposed subjects. The ctDCS intervention had an effect on the 'Normalised Step length Affected side' (p=0.1) and 'Gait Stability Ratio' (p=0.0569), which was found using Wilcoxon signed-rank test at 10% significance level. Also, ctDCS montage specific effect was found using a two-sided Wilcoxon rank-sum test at a 5% significance level for 'Step Time Affected Leg' (p=0.0257) and '%Stance Time Unaffected Leg' (p=0.0376). Moreover, the changes in the quantitative gait parameters across both the montages were found to be correlated to the mean electric field strength in the lobules based on partial least squares regression analysis (R2 statistic = 0.6574) where the mean electric field strength at the cerebellar lobules, Vermis VIIIb, Ipsilesional IX, Vermis IX, Ipsilesional X, had the most loading. In conclusion, our feasibility study indicated the potential of a single session of ctDCS to contribute to the immediate improvement in the balance and gait performance in terms of gait-related indices and clinical gait measures.

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