Light emission spectra of molecules in negative and positive back discharges in nitrogen with carbon dioxide mixture at atmospheric pressure

Results of spectroscopic investigations and current-voltage characteristics of back discharge generated in point-plane electrode geometry with plate covered fly ash layer in a mixture of N2 + CO2 at atmospheric pressure, for positive and negative polarity of the discharge electrode are presented in this paper. Point-plane electrode configuration was chosen in these studies in order to simulate the physical processes occurring in electrostatic precipitator. Three forms of back discharge for both polarities were investigated: glow, streamers and low-current back-arc. Diatomic reactions and dissociation products of N2 and CO2 (OH, NO, CN), atoms from fly ash layer (N, Ti, Na), free radicals, molecules or ions, which have unpaired valence electrons, and other active species, e.g., N2 (in C,B,A-state), N\hbox{$_{2}^{+}$} (B) were identified in the discharges by the method of optical emission spectroscopy (OES). The measurements shown that atomic and molecular optical emission spectral lines from back discharge depend on the forms of discharge and the discharge current. In normal electrical discharges, the emission spectra are dominated by gaseous components, but in the case of back discharge, atomic lines belonging to chemical compounds of fly ash were also recorded and identified

Studies of corona and back discharges in carbon dioxide

Results of spectroscopic investigations and current-voltage characteristics of corona and back discharges generated in point-plane electrode geometry in CO2 at atmospheric pressure for positive and negative polarity of the discharge electrode are presented in the paper. Three forms of back discharge, for both polarities, were investigated: glow, streamer and low-current back-arc. To generate the back-discharges for the conditions similar to electrostatic precipitator, the plate electrode was covered with fly ash layer. In order to characterize back discharge processes, the emission spectra were measured and compared with those obtained for normal discharge, generated in the same electrode configuration but without the fly ash layer on the plate electrode. The measurements have shown that optical emission spectral lines of atoms and molecules, excited or ionised in back discharge, depend on the forms of the discharge, the discharge current, and are different in the zones close to needle electrode and fly ash layer. From the comparison of spectral lines of back and normal discharges, an effect of fly ash layer on discharge characteristics and morphology has been determined. In normal corona, the emission spectra are mainly predetermined by the working gas components, but in the case of back discharge, the atomic and molecular lines, resulting from chemical composition of fly ash, are also identified. Differences in the spectra of back discharge for positive and negative polarities of the needle electrode have been explained by considering the kind of ions generated in the crater in fly ash layer. For back arc, the emission of spectral lines of atoms and molecules from fly ash layer can be recorded in the crater zone, but in the needle zone, only the emission lines of CO2 and its decomposition products (CO and C2) can be noticed. The studies of back discharge in CO2, as one of the main components of flue gases, were undertaken because this type of discharge, after unwanted inception, decreases the energy and collection efficiencies of electrostatic precipitator. The second reason behind these studies is that CO2 is the main component of flue gas leaving oxyfuel boiler that re-circulates in the combustion-precipitation cycle. It was shown that discharges in CO2 lead to contamination of discharge electrode with carbonaceous products that can cause severe maintenance problems of electrostatic precipitator. The recognition of the characteristics of electrostatic precipitator operating in the oxyfuel system is, therefore, of crucial importance for exhaust gas cleaning in modern combustion systems

Particulate matter emission reduction from marine diesel engines by electrohydrodynamic methods

Particulate matter (PM) and gaseous compounds (SO2, NOx, VOC) emitted by diesel engines causes serious global environmental problems and health impact. Despite numerous evidences about the harmfulness of diesel particles, the PM emission by diesel engines used by ships, cars, agricultural machines, or power generators is still unregulated, and the efficient removal of PM from diesel exhausts is still the major technological challenge. In order to comply with the International Maritime Organization regulation, the NOx emission is reduced by using selected catalytic reactor, and sulphur oxide emission has been reduced by using fuels of low sulphur content. However, both of those measures cannot be used for the reduction of PM emission produced during combustion of marine fuels. The lack of appropriate regulations results from insufficiently developed technology, which could remove those particles from exhaust gases. Conventional scrubbers currently available on the market remove only sulphur oxide with required collection efficiency, but the collection efficiency for PM2.5 is below 50%. The article discusses the technical means used for the removal of PM from marine diesel engines via applying electrohydrodynamic methods, in particular electrostatic agglomeration, as a method of nanoparticles coagulation to larger agglomerates, which could operate in two-stage electrostatic precipitation systems, and electrostatic scrubbers, which remove particles by electrically charged water droplets. The experimental results were obtained for a 2-stroke 73 kW diesel engine fuelled with marine gas oil (MGO). The agglomerator allowed increasing the collection efficiency from diesel exhausts for PM2.5 particles by about 12%, compared to electrostatic precipitator operating without agglomerator, and the total mass collection efficiency was above 74%. The collection efficiency of electrostatic scrubber was higher than 95wt.%. The advantage of using the electrostatic scrubber is that it can also reduce the SO2 emission by more than 90%, when HFO is used

Selected Indices of Anaerobic Capacity and Their Changes during Special Judo Fitness Tests at Different Ambient Temperatures Performed among Judo Athletes

Background: Thermoregulatory processes play an important role during athletic competition. When athletes compete in an elevated ambient temperature, metabolic processes in their bodies become intensified. The main objective of the study was to determine changes in anaerobic total work (TW) and relative peak power (RPP) during a special judo fitness test at different ambient temperatures performed among judo athletes. Methods: The study included 15 judo athletes aged 20.7 ± 2.0 years, with a body height of 178 ± 6.3 cm, body mass totalling 76.3 ± 12.6 kg, VO2max at 43.2 ± 7.8 mL·kg−1, and peak power of 12.1 W·kg−1. A complete set of results was obtained for 10 athletes. In the main part of the examinations, judo athletes performed five sequences (7.20 min each), alternating efforts on a leg cycle and arm cycle ergometer in a thermal chamber at 21 ± 0.5 °C and 31 ± 0.5 °C. The efforts differed from typical interval exercise by alternating upper- and lower-limb efforts, as well as with regard to the duration of those efforts. Each sequence was followed by a 15 min interval for rest. In each sequence, subjects performed four anaerobic tests with the upper and lower limbs. Results: In the first of five series of efforts performed with the lower limbs (LL) at an ambient temperature of 21 °C, statistically significant differences (p p < 0.001) and between the second and third performed using the upper limbs (UL) at an ambient temperature of 21 °C Conclusions: Varying ambient thermal conditions do not affect the size of generated relative peak power or the volume of work performed in pulsating anaerobic exercise

Selected Indices of Anaerobic Capacity and Their Changes during Special Judo Fitness Tests at Different Ambient Temperatures Performed among Judo Athletes

Background: Thermoregulatory processes play an important role during athletic competition. When athletes compete in an elevated ambient temperature, metabolic processes in their bodies become intensified. The main objective of the study was to determine changes in anaerobic total work (TW) and relative peak power (RPP) during a special judo fitness test at different ambient temperatures performed among judo athletes. Methods: The study included 15 judo athletes aged 20.7 &plusmn; 2.0 years, with a body height of 178 &plusmn; 6.3 cm, body mass totalling 76.3 &plusmn; 12.6 kg, VO2max at 43.2 &plusmn; 7.8 mL&middot;kg&minus;1, and peak power of 12.1 W&middot;kg&minus;1. A complete set of results was obtained for 10 athletes. In the main part of the examinations, judo athletes performed five sequences (7.20 min each), alternating efforts on a leg cycle and arm cycle ergometer in a thermal chamber at 21 &plusmn; 0.5 &deg;C and 31 &plusmn; 0.5 &deg;C. The efforts differed from typical interval exercise by alternating upper- and lower-limb efforts, as well as with regard to the duration of those efforts. Each sequence was followed by a 15 min interval for rest. In each sequence, subjects performed four anaerobic tests with the upper and lower limbs. Results: In the first of five series of efforts performed with the lower limbs (LL) at an ambient temperature of 21 &deg;C, statistically significant differences (p &lt; 0.001) were found between the mean RPP values recorded during the first and third and fourth repetitions, and between the second versus third and fourth repetitions. Statistically significant differences were also observed between the first and fourth efforts performed by the LL at 31 &deg;C (p &lt; 0.001) and between the second and third performed using the upper limbs (UL) at an ambient temperature of 21 &deg;C Conclusions: Varying ambient thermal conditions do not affect the size of generated relative peak power or the volume of work performed in pulsating anaerobic exercise

SUBMICRON PARTICLES EMISSION CONTROL BY ELECTROSTATIC AGGLOMERATION

The aim of the study was to develop a device for more effective treatment of flue gases from submicron particles emitted by power plants burning bituminous coal and by this way the reduction of environment pollution. Electrostatic processes were employed to this goal, as the most effective solution. The solutions hitherto applied in electrostatic precipitation techniques were designed for large particles, typically with sizes> 5 µm, which are easily removed by the action of electrostatic force on the electrically charged particles. In submicron size range (0.1-1 µm) the collection efficiency of an ESP is minimal, because of the low value of electric charge on such particles. In order to avoid problems with the removal of submicron particles of fly ash from the flue gases electrostatic agglomeration has been used. In this process, by applying an alternating electric field, larger charged particles (> 1 µm) oscillate, and the particles "collect" smaller uncharged particles. In the developed agglomerator with alternating electric field, the charging of particles and the coagulation takes place in one stage that greatly simplified the construction of the device, compared to other solutions. The scope of this study included measurements of fractional collection efficiency of particles in the system comprising of agglomerator and ESP for PM1 and PM2.5 ranges, in device made in pilot scale. The collection efficiency for PM2.5 was greater than 90% and PM1 slightly dropped below 90%. The mass collection efficiency for PM2.5 was greater than 95%. The agglomerator stage increases the collection efficiency for PM1 at a level of 5-10%

SUBMICRON PARTICLES EMISSION CONTROL BY ELECTROSTATIC AGGLOMERATION

The aim of the study was to develop a device for more effective treatment of flue gases from submicron particles emitted by power plants burning bituminous coal and by this way the reduction of environment pollution. Electrostatic processes were employed to this goal, as the most effective solution. The solutions hitherto applied in electrostatic precipitation techniques were designed for large particles, typically with sizes> 5 µm, which are easily removed by the action of electrostatic force on the electrically charged particles. In submicron size range (0.1-1 µm) the collection efficiency of an ESP is minimal, because of the low value of electric charge on such particles. In order to avoid problems with the removal of submicron particles of fly ash from the flue gases electrostatic agglomeration has been used. In this process, by applying an alternating electric field, larger charged particles (> 1 µm) oscillate, and the particles "collect" smaller uncharged particles. In the developed agglomerator with alternating electric field, the charging of particles and the coagulation takes place in one stage that greatly simplified the construction of the device, compared to other solutions. The scope of this study included measurements of fractional collection efficiency of particles in the system comprising of agglomerator and ESP for PM1 and PM2.5 ranges, in device made in pilot scale. The collection efficiency for PM2.5 was greater than 90% and PM1 slightly dropped below 90%. The mass collection efficiency for PM2.5 was greater than 95%. The agglomerator stage increases the collection efficiency for PM1 at a level of 5-10%

Dylematy tożsamości: stare i nowe konteksty socjalizacji

Praca recenzowana / peer-reviewed pape

Dataset for "Magnetic field generation using single-plate targets driven by kJ-ns class laser"

Dataset underpinning the results presented in the article titled, "Magnetic field generation using single-plate targets driven by kJ-ns class laser" published in Plasma Physics Controlled Fusion (2020) Abstract of the paper: Strong magnetic fields of upto 20 T, corresponding to a current of tens of kA were produced in a coil connected to a single-plate of cm2 area irradiated by a kJ-ns laser pulse. The use of such macroscopic plates protects the coil from plasma debris, while maintaining a strong magnetic field for a time-scale much longer than the laser pulse duration. By correlating the measured magnetic field in the coil to the number of electrons emitted from the interaction zone, we deduce that the target capacitance is enhanced by two orders of magnitude because of the plasma sheath in the proximity of the focal spot. Particle-in-cell simulations illustrate the dynamics of sheath potential and current flow through the coil to ground, thus closing the circuit due to the escape of laser-produced hot electrons from the target