scholarly journals Patterns of inhibition of the culture of Salmonella

2019 ◽  
Vol 80 (4) ◽  
pp. 209-212 ◽  
Author(s):  
N. V. Ilyuhina ◽  
A. Yu. Kolokolova
Keyword(s):  
Electron Beams ◽  
Dose Range ◽  
Model Systems ◽  
Beam Power ◽  
Average Electron Energy ◽  
Model Liquid ◽  
Initial Degree ◽  
Serovar Typhimurium ◽  
Average Electron ◽  
Structure Density

Studies on the inhibition effectiveness of the initial degree of inoculation of the Salmonella microorganism were carried out. In this paper, the irradiation efficiency of model systems with electron beams with beam energy of 6.5 and 10 MeV was studied. The investigations were carried out at UELV-10-10-C-70 accelerator at Frumkin Institute of Physical Chemistry and Electrochemistry of Russian Academy of Sciences (IPCE RAS) with an average beam power of 6.5 MeV and at radiation-technological center with an electron accelerator UELR-10-10-40 at A.I. Burnazyan Federal Medical Biophysical Centre of Federal Medical Biological Agency with an average electron energy of 10 MeV. The conducted researches on studying and revealing the dependence of inhibition of pathogenic microflora, irradiation with different intensity, on the structure (density) of the studied samples, which model liquid and solid nutrient media. The study used a strain Salmonella enterica subsp. Enterica serovar Typhimurium. The results of the effective inhibition of the initial degree of contamination for the two plants were obtained. Studies have shown that the effectiveness of inhibition of Salmonella culture can vary depending on the characteristics of electron beams. For example, when samples were irradiated with electrons with energy of 6.5 and 10 MeV at doses from 3 to 7 kGy, various results of the inhibition effectiveness of Salmonella culture on media with different work were obtained. When processing samples with studied strains of cultures in the dose range from 4 to 5 kGy, there is an increase in the growth of microorganisms for all processing conditions. In the remaining studied ranges their inhibition are observed. It is important to take into account not only the effectiveness of the oppression of microflora on specific products, but also the efficiency of the installation for a specific sample.

scholarly journals Филаментация и самофокусировка электронных пучков в вакуумных и газовых диодах

2019 ◽  
Vol 45 (7) ◽  
pp. 3
Author(s):  
В.И. Олешко ◽  
В.Ф. Тарасенко ◽  
А.Г. Бураченко ◽  
V.V. Nguyen
Keyword(s):  
Energy Density ◽  
Electron Beams ◽  
Local Density ◽  
Beam Current ◽  
Beam Current Density ◽  
Runaway Electrons ◽  
Beam Current Pulse ◽  
Average Electron Energy ◽  
Interelectrode Gap ◽  
Average Electron

AbstractIn this paper, we experimentally studied pulsed electron beams with a high local density. The conditions in which the energy density cumulation is observed during the interaction of electrons with the anode are shown to develop in vacuum and gas diodes at nanosecond and subnanosecond durations of a beam current pulse and a decrease in the interelectrode gap. The average electron energy in filamentation and self-focusing of an electron beam in a vacuum diode of an accelerator at a current of ~2 kA and a no-load voltage of ~400 kV was established to be 50–100 keV while the energy density was 10^9–10^10 J/cm^3. It is confirmed that the beam current density in a gas diode can exceed 1 kA/cm^2. It is hypothesized that superdense electron beams in vacuum and gas diodes are formed as a result of avalanche multiplication of runaway electrons in the cathode–anode gap plasma.

All that is known about Mars discrete aurorae so far

2021 ◽  
Author(s):  
Lauriane Soret ◽  
Zachariah Milby ◽  
Jean-Claude Gérard ◽  
Nick Schneider ◽  
Sonal Jain ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Emission Layer ◽  
Atmospheric Effect ◽  
Average Electron Energy ◽  
Mars Express ◽  
Spatially Correlated ◽  
Auroral Emissions ◽  
Average Electron ◽  
First Time ◽  
Imaging Spectrograph

<p>The discrete aurorae on Mars were discovered with the SPICAM spectrograph on board Mars Express. Now, they have been analyzed in detail using the much more sensitive MAVEN/IUVS imaging spectrograph.</p><p>This presentation gives a summary of the very latest results obtained by Schneider et al. and Soret et al. on this topic.</p><p>The main conclusions are the following:</p><ul><li>the number of auroral event detections has considerably increased since the Mars Express observations;</li> <li>many detections have been made outside of the Southern crustal magnetic field structures;</li> <li>the MUV spectrum shows the same emissions as those observed in the dayglow, with similar intensity ratios;</li> <li>the Vegard-Kaplan bands of N<sub>2</sub> have been observed for the first time in the Martian aurora;</li> <li>the CO Cameron and the CO<sub>2</sub><sup>+</sup> UVD emissions occur at the same altitude;</li> <li>the OI emission at 297.2 nm has been analyzed;</li> <li>the CO Cameron/CO<sub>2</sub><sup>+</sup> UVD ratio is quasi-constant;</li> <li>intensities are higher in B-field regions;</li> <li>auroral emissions are more frequent in the pre-midnight sector;</li> <li>the altitude of the emission layer is independent of local time and presence or absence of a crustal magnetic field;</li> <li>the altitude of the emission layer varies moderately with season (atmospheric effect);</li> <li>the events are spatially correlated with an increase in the flux of energetic electrons simultaneously measured by the MAVEN/SWEA (Solar Wind Electron Analyzer) detectors;</li> <li>the peak altitude of the emission is in good agreement with that expected from the average electron energy.</li> </ul>

Measurements of Electron Energy by Emission Spectroscopy in Pulsed Corona and Dielectric Barrier Discharges

2003 ◽  
Vol 6 (1) ◽  
Author(s):  
Yongho Kim ◽  
Sang Hee Hong ◽  
Min Suk Cha ◽  
Young-Hoon Song ◽  
Seock Joon Kim
Keyword(s):  
Electron Energy ◽  
Spectroscopic Method ◽  
Optical Emission ◽  
Dielectric Barrier Discharges ◽  
Time Resolved ◽  
Average Electron Energy ◽  
Dielectric Barrier ◽  
Pulsed Corona ◽  
Average Electron ◽  
Barrier Discharges

AbstractElectric field distributions and average electron energies are measured by an optical emission spectroscopic method to investigate streamer characteristics in a pulsed corona discharge (PCD) and a dielectric barrier discharge (DBD) in atmospheric air. In PCD, average electron energies appear to be in the range of 10 ~ 12 eV along the streamers. Time-resolved measurements show that streamers in DBD have a relatively low value of average electron energy of 9 ~ 10 eV. Enhancement of the electron energy is observed when DBD is operated in a non-uniform geometry, such as dielectric barrier with a hole.

scholarly journals The Influence of Humidity on Electron Transport Parameters and Insulation Performance of Air

2022 ◽  
Vol 9 ◽  
Author(s):  
Yunzhu An ◽  
Menghan Su ◽  
Yuanchao Hu ◽  
Shangmao Hu ◽  
Tao Huang ◽  
...  
Keyword(s):  
Electron Transport ◽  
Relative Humidity ◽  
Electron Energy ◽  
Transport Parameters ◽  
Average Electron Energy ◽  
Electron Diffusion Coefficient ◽  
External Insulation ◽  
Calculation Results ◽  
Average Electron ◽  
Insulation Performance

The environmental conditions affect the external insulation performance of power equipment. In order to study the physical characteristics of air discharge, the microscopic process of electron–molecule collision in the air based on the Boltzmann equation has been studied in this paper. The influence of humidity on the air gap insulation performance was also analyzed. The calculation results show that with the temperature 300 K and the pressure 1.0 atm, the electron energy distribution function and electron transport parameters varied with the air relative humidity. As the air relative humidity is increased by each 30%, the average electron energy decreases by about 0.2 eV, the reduced electron mobility decreases by about 0.25 × 1023 [1/(V·m·s)], the reduced electron diffusion coefficient decreases by about 0.2 × 1024 [1/(m s)], and the effective ionization coefficient decreases by about 4 × 10−24 m2. As the air relative humidity increases from 0% to 60%, the critical breakdown electric field increases by 1.22 kV/cm.

scholarly journals Влияние вида функции распределения электронов в плазме и дисперсии по энергии электронного пучка на устойчивость низковольтного пучкового разряда

2021 ◽  
Vol 91 (4) ◽  
pp. 579
Author(s):  
В.С. Сухомлинов ◽  
P.М. Матвеев ◽  
А.С. Мустафаев ◽  
В.А. Павлов ◽  
С.В. Гордеев
Keyword(s):  
Electron Beam ◽  
Electron Energy ◽  
Low Voltage ◽  
Mean Free Path ◽  
Inert Gases ◽  
Loss Of Stability ◽  
Average Electron Energy ◽  
Cathode Temperature ◽  
Average Electron ◽  
Electron Mean Free Path

Within the framework of the kinetic approach, the conditions for the loss of stability of a low-voltage beam discharge in inert gases (LVBD) are studied depending on the temperature of the electron beam, the dispersion of the electron beam velocity in the direction of the discharge axis, and the form of the electron energy distribution function (EEDF). Regimes are considered when the interelectrode distance is on the order of the electron mean free path relative to elastic collisions with inert gas atoms. It is shown that the beam temperature Tb, determined in the LVBD by the cathode temperature not exceeding 1500 K, and the dispersion of the beam electron energy, which in the LVBD can be significantly higher than kTb and reaches 1 - 2 eV, have little effect on the conditions for the loss of stability of the LVBD and the magnitude of the growth rate of disturbance amplification at frequencies up to plasma It was found that the form of the EEDF monotonically decreasing with increasing electron energy also does not affect the parameters of the perturbations propagating in the LVBD at the beam energy much higher than the average electron energy in the plasma. The results obtained are applicable not only to LVBD, but also to other types of self-sustained beam discharges.

III.—Statistics of the Electron-Multiplication Process in Proportional Counters

1962 ◽  
Vol 66 (1) ◽  
pp. 33-41 ◽  
Author(s):  
J. Byrne
Keyword(s):  
Proportional Counter ◽  
Ionization Energy ◽  
Dimensional Model ◽  
Average Electron Energy ◽  
Mean Values ◽  
Electron Multiplication ◽  
Multiplication Process ◽  
The Mean ◽  
Average Electron ◽  
Conventional Type

SynopsisThis paper is concerned with the theory of the probability distribution of the total number of electrons in the avalanche produced by the release of a single electron in the gas of a proportional counter. The disagreement between existing theory and experimental results is discussed and a new theory is proposed, based on the fact that fluctuations in the number of electrons at a given point in the avalanche are accompanied by fluctuations in the average electron energy. This aspect of the problem is incorporated directly into a simple one-dimensional model of the multiplication process, and the resulting distribution function has a mathematical foim in agreement with that observed experimentally.The fluctuation in the number of electrons predicted by this theory is not constant, but is determined by a parameter which, for large mean values, is essentially the mean fraction of electrons in the avalanche having energies above the ionization energy of the counter gas. Limits on the variation of this parameter are obtained by calculations of the mean values using a particular two-dimensional model, in which electrons are divided into two classes according as they have energies above, or below, the ionization energy. The experimentally observed fluctuation lies within the predicted range and close to the lower limit; it is concluded that there is little scope for improvement in the resolution to be obtained from the conventional type of proportional counter.

Polimer Gafchromic EBT3 Films in Clinical Dosimetry

2015 ◽  
Vol 1084 ◽  
pp. 572-576 ◽  
Author(s):  
Evgeniia Sukhikh ◽  
Leonid Sukhikh ◽  
Evgeniy Malikov
Keyword(s):  
Polymer Film ◽  
Electron Beams ◽  
Dose Range ◽  
Film Dosimetry ◽  
Photon Beams ◽  
Calibration Curves ◽  
Electron And Photon

The results of the calibration of the Gafchromic EBT3 polymer film for photon and electron beams with different energies are presented. The results of these studies show that the use of film dosimetry for electron and photon beams in the dose range 0.2 - 40 Gy is possible. The resulting calibration curves are the same for electrons with different energies (2 MeV, 10 MeV), but there exists a difference for photons with the energy of 10 MV and 70 kV.

Energy relaxation for thermal electrons in CO

1968 ◽  
Vol 46 (11) ◽  
pp. 1323-1330 ◽  
Author(s):  
Michael H. Mentzoni ◽  
James Donohoe
Keyword(s):  
Electron Energy ◽  
Cross Sections ◽  
Loss Rate ◽  
Dipole Interaction ◽  
Energy Relaxation ◽  
Average Electron Energy ◽  
Cross Modulation ◽  
Energy Relaxation Time ◽  
Average Electron ◽  
Electron Energy Loss

Using published cross sections for rotational excitation and de-excitation caused by dipole and quadruple interactions in carbon monoxide, the average electron energy loss rate, [Formula: see text], is computed as a function of excess electron temperature, Te − T, for the case of a maxwellian velocity distribution for various gas temperatures, T. It is found that the dipole and quadrupole contributions to the loss rate are in the ratio 3:1 with the composite electron energy relaxation time given by pτ = 338 ns Torr for Tgas = 300 °K. The initial values of [Formula: see text] caused by dipole interaction decrease more rapidly with temperature than T−1/2, which was the temperature variation found in the case of quadrupole interaction. Experimentally, microwave cross-modulation results pertaining to the isothermal afterglow of a d-c. discharge in CO yielded the value pτ = 113 ± 11 ns Torr for T = 300 °K. The apparent discrepancy between theory and experiment is discussed.

Kinetic Analysis of Chlorofluorocarbon Discharges

1984 ◽  
Vol 38 ◽  
Author(s):  
Herbert H. Sawin ◽  
Akimichi Yokozeki ◽  
Aaron J. Owens ◽  
Kenneth D. Allen
Keyword(s):  
Electron Impact ◽  
Etching Rate ◽  
Threshold Energy ◽  
Electron Attachment ◽  
Impedance Analysis ◽  
Average Electron Energy ◽  
Electrode Surfaces ◽  
Positive Ions ◽  
Rate Limiting Step ◽  
Average Electron

AbstractThe fundamental plasma kinetics of chlorofluorocarbon discharges have been studied experimentally and modeled. Electrical impedance analysis of the plasma discharge during the etching process was used to estimate the average electron energy and the electron concentration. Assuming the electron-impact generation of reactant species is the rate limiting step, the etching rate of polysilicon etching was modeled using a simplified expression for the electron-impact rate coefficient for dissociation and the experimentally estimated electron densities and electron energies. Dissociative electron attachment should play a significant role in the production of etchant species at low electron energies. The lower threshold energy and the larger cross-section (σ) for dissociative attachment of chlorofluorocarbons (σmax,∼6×10-18 cm2 at ∼ 3 eV for CF3Cl) in coomprpsanrtison to that of fluorocarbons (σmax ∼0.8×10-18 cm2 at ∼7 eV for CF4 ), increases the significance of this machanism in chlorofluorocarbon discharges. In addition, the production of appreciable concentrations of C1- could influence the transport of positive ions to the electrode surfaces.

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