scholarly journals Drift Velocity, Longitudinal and Transverse Diffusion in Hydrocarbons derived from Distributions of Single Electrons

1992 ◽  
Vol 45 (3) ◽  
pp. 351 ◽  
Author(s):  
Bernhard Schmidt ◽  
Michael Roncossek
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Drift Velocity ◽  
Simultaneous Measurement ◽  
Diffusion Coefficients ◽  
Number Density ◽  
Transverse Diffusion ◽  
Single Electrons ◽  
Time Of Flight Method

A time of flight method is described which allows the simultaneous measurement of drift velocity w and the ratios of the longitudinal and transverse diffusion coefficients to mobility (DL/JL, DT/JL) of electrons in gases. The accuracy achieved in this omnipurpose experiment is comparable with that of specialised techniques and is estimated to be �1 % for w and �5% for the D / JL measurements .. Results for methane, ethane, ethene, propane, propene and cyclopropane for values of E/N (the electric field strength divided by the number density) ranging from 0�02 to 15 Td are presented and discussed (1 Td = 10-21 Vm2 ).

scholarly journals Ion?Molecule Reactions and Mobilities of SF3+ and SF5+ Ions in SF6 Gas

1993 ◽  
Vol 46 (6) ◽  
pp. 799 ◽  
Author(s):  
ZA Talib ◽  
M Saporoschenko
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Drift Tube ◽  
Ion Source ◽  
Zero Field ◽  
Number Density ◽  
Mobility Data ◽  
Ion Molecule Reactions ◽  
Positive Ion

Positive ion-molecule reactions in 8F6 were studied in a static drift-tube mass spectrometer using electron impact at 100 eY as the ion source. The ratio of electric field strength to gas number density, E / N, was typically varied from 40-282 Td and pressure ranged from 0�1 to o� 8 Torr. The most important processes were found to be 8Ft + SF6 ---+ 8Ft + 8F6 + F2 and 8Ft + 8F6 ---+ (82Fg)+* ---+ 82Ft + F 2. The interaction potentials for the 8Ft and 8Ft ions in SF6 were also found by using the measured mobility data which were obtained using a pulsed-ion transit-time method. We found that the (12,4, a* = 0�1) core model was adequate to describe the mobility over the range of E / N studied. The zero-field reduced mobilities for 8Ft and 8Ft were determined to be 0�68 and 0�55cm2y-1 s- 1 respectively.

scholarly journals Drift Velocity and DT/m Ratio for Electrons in a 0.5% Hydrogen?Xenon Mixture at 295 K

1994 ◽  
Vol 47 (3) ◽  
pp. 253 ◽  
Author(s):  
MT Elford ◽  
S Sasaki ◽  
KF Ness
Keyword(s):  
Cross Section ◽  
Drift Velocity ◽  
Diffusion Chamber ◽  
Number Density ◽  
Velocity Measurements ◽  
Transverse Diffusion ◽  
Xenon Mixture ◽  
Time Of Flight Method ◽  
Momentum Transfer Cross Section ◽  
Electron Transport Coefficient

The momentum transfer cross section for electrons in xenon, am, has been studied using electron transport coefficient measurements for a dilute hydrogen-xenon mixture (0�47% H2- 99 �53% Xe). Drift velocity measurements were made using the Bradbury-Nielsen time-of-flight method at E/N values from 0 �12 to 2�50 Td, pressures from 10�3 to 94�0 kPa and a temperature of 295 K (E is the electric field strength and N the gas number density; 1 Td == 10-17 Vcm2). The ratio DT/f.t (where DT is the transverse diffusion coefficient and {� the electron mobility) was measured using a Townsend-Huxley diffusion chamber at E/N values from 0�035 to 1� 70 Td, pressures from 13�4 to 40�3 kPa, and a temperature of 294 K. Three recently published Urn values for xenon have been tested and shown to be incompatible with both the present drift velocity and DT / f.t measurements.

scholarly journals The Ratio DT/µ for Electrons in Water Vapour at 294 K

1995 ◽  
Vol 48 (3) ◽  
pp. 427 ◽  
Author(s):  
MT Elford
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Water Vapour ◽  
Number Density ◽  
Current Ratio ◽  
N Value ◽  
Good Agreement

The ratio DT /� for electrons in water vapour (294 K) has been measured by the TownsendHuxley method as a function of E/N (where E is the electric field strength and N the gas number density) at vapour pressures ranging from 0 �103 to 0�413 kPa. For E/N 30 Td were found to be strongly pressure dependent, the strength and sign of the dependence depending on E/N and the current ratio relation used. Since extrapolation to infinite pressure at each E/N value did not give the same value of DT/ u, it has not been possible to derive reliable DT/ J.l values for this higher E/N range. Possible causes of the observed pressure dependences are discussed. The present data are in good agreement with the values predicted by Ness and Robson for values of E/N ~ 24 Td.

scholarly journals Magnetic Deflection Coefficient Investigation for Low Energy Particles

2011 ◽  
Vol 8 (2) ◽  
pp. 304-317 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Drift Velocity ◽  
Theoretical Data ◽  
Low Energy ◽  
Boltzmann Transport ◽  
Transport Parameters ◽  
Deflection Coefficient ◽  
Magnetic Deflection

In this research we solved numerically Boltzmann transport equation in order to calculate the transport parameters, such as, drift velocity, W, D/? (ratio of diffusion coefficient to the mobility) and momentum transfer collision frequency ?m, for purpose of determination of magnetic drift velocity WM and magnetic deflection coefficient ? for low energy electrons, that moves in the electric field E, crossed with magnetic field B, i.e; E×B, in the nitrogen, Argon, Helium and it's gases mixtures as a function of: E/N (ratio of electric field strength to the number density of gas), E/P300 (ratio of electric field strength to the gas pressure) and D/? which covered a different ranges for E/P300 at temperatures 300°k (Kelvin). The results showed had been tabulated and graphically represented as functions of their variables. These results a satisfactory agreement between experimental values and theoretical data given in the literature showed.

Optical Measurement of the Electric Field Strength in a Gel Insulator

2016 ◽  
Vol 136 (10) ◽  
pp. 1420-1421
Author(s):  
Yusuke Tanaka ◽  
Yuji Nagaoka ◽  
Hyeon-Gu Jeon ◽  
Masaharu Fujii ◽  
Haruo Ihori
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Optical Measurement

Effect of external magnetic field on lane formation in driven pair-ion plasmas

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
Swati Baruah ◽  
U. Sarma ◽  
R. Ganesh
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Coupling Parameter ◽  
Critical Parameters ◽  
Coulomb Coupling ◽  
Lane Formation ◽  
Parameter Values

Lane formation dynamics in externally driven pair-ion plasma (PIP) particles is studied in the presence of external magnetic field using Langevin dynamics (LD) simulation. The phase diagram obtained distinguishing the no-lane and lane states is systematically determined from a study of various Coulomb coupling parameter values. A peculiar lane formation-disintegration parameter space is identified; lane formation area extended to a wide range of Coulomb coupling parameter values is observed before disappearing to a mixed phase. The different phases are identified by calculating the order parameter. This and the critical parameters are calculated directly from LD simulation. The critical electric field strength value above which the lanes are formed distinctly is obtained, and it is observed that in the presence of the external magnetic field, the PIP system requires a higher value of the electric field strength to enter into the lane formation state than that in the absence of the magnetic field. We further find out the critical value of electric field frequency beyond which the system exhibits a transition back to the disordered state and this critical frequency is found as an increasing function of the electric field strength in the presence of an external magnetic field. The movement of the lanes is also observed in a direction perpendicular to that of the applied electric and magnetic field directions, which reveals the existence of the electric field drift in the system under study. We also use an oblique force field as the external driving force, both in the presence and absence of the external magnetic field. The application of this oblique force changes the orientation of the lane structures for different applied oblique angle values.

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.

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