scholarly journals Influence of contraction of a cesium pulse-periodic discharge on its luminous efficacy and spectral properties

2021 ◽  
Vol 2103 (1) ◽  
pp. 012220
Author(s):  
A A Bogdanov ◽  
S V Gavrish ◽  
A M Martsinovsky ◽  
I I Stolyarov
Keyword(s):  
Current Pulse ◽  
Spectral Properties ◽  
Plasma Temperature ◽  
Interelectrode Distance ◽  
Discharge Column ◽  
Luminous Efficacy ◽  
Periodic Discharge ◽  
Discharge Tubes ◽  
Short Tube

Abstract The paper presents the results of a study of pulse-periodic discharge cesium lighting lamps with discharge tubes 5 mm in diameter and an interelectrode distance of 55 and 22 mm. The cesium pressure varied from 10 to 750 Torr at a constant triangular current pulse with an amplitude of 80 A. It is shown that the maximum of the luminous efficacy (~ 65 lm/W) corresponds to a pressure of ~ 130 Torr. It was found that a discharge column in the long tube at a pressure of ~ 300 Torr contracted into a bright pinch with a diameter close to that of the electrodes (2 mm). The pinch was localized along the surface of the tube and moves randomly on it. Contraction leads to a repeated increase in the luminous efficacy with pressure up to ~ 70 lm/W. Wall stabilization limits the plasma temperature on the axis of the pinch (it was found from the recombination continuum) to the level of 6000 – 6500 K. The column in short tube is localized along the axis of the tube over the entire power range. The temperature in it quickly rises to 13000-– 14000 K after the maximum of the luminous efficacy.

Experimentelle Untersuchungen an Drahtexplosionsentladungen im Hochvakuum / Experimental Investigation of Exploding Wire Discharges in High Vacuum

1969 ◽  
Vol 24 (11) ◽  
pp. 1707-1715 ◽  
Author(s):  
Lutz Niemeyer
Keyword(s):  
Axial Magnetic Field ◽  
High Vacuum ◽  
Thermionic Emission ◽  
Plasma Temperature ◽  
Radial Electric Field ◽  
Discharge Column ◽  
Contraction Phase ◽  
Heated Wire ◽  
The Mean ◽  
The Wire

Explosions of 0.03 -0.25 mm diameter wires of Cd, AI, Cu, and W in high vacuum (p < 10-5 Torr) are investigated. The time development of the discharge column is shown to be determined by two main processes: a) In the time preceding the explosion, particles are emitted from the surface of the heated wire and initiate a peripheral discharge. The mechanism of particle emission is found to be evaporation of neutral atoms and/or thermionic emission of charged particles. The latter process is influenced by the strong radial electric field which is caused by the coaxial discharge geometry at the wire surface, b) The wire material vaporizes explosively forming an expanding cloud of nonconducting vapor which is subsequently converted to a plasma by the peripheral discharge penetrating into it from outside. The discharge column exhibits instabilities which are shown to be of MHD origin. They are significantly reduced by applying an axial magnetic field to the discharge column. A quantitative spectroscopic investigation is performed during the magnetic contraction phase of stabilized 0.05 mm Al wire explosions. The plasma temperature is found to be about 50 000 °K in the axis of the column and higher than 80 000 °K at its periphery. The mean electron density is estimated to be of the order of some 1019 cm-3 .

Dynamics of the development of high-current pulse-periodic discharge in cesium vapor

2015 ◽  
Vol 41 (7) ◽  
pp. 694-696 ◽  
Author(s):  
S. V. Gavrish ◽  
V. B. Kaplan ◽  
A. M. Martsinovskii ◽  
I. I. Stolyarov
Keyword(s):  
Current Pulse ◽  
Cesium Vapor ◽  
High Current ◽  
Periodic Discharge

scholarly journals Influence of spectral properties of light sources on perceived and recorded images

2021 ◽  
Vol 13 (2) ◽  
pp. 40
Author(s):  
Jacek Kusznier
Keyword(s):  
White Light ◽  
Power Distribution ◽  
Spectral Properties ◽  
Spectral Power ◽  
Electrical Engineering ◽  
Climatic Conditions ◽  
Light Sources ◽  
Luminous Efficacy ◽  
Spectral Power Distribution

The text presents differences between the mechanism of seeing and recording images and potential sources of errors in color reproduction in recorded images. The measurements show that despite the relatively high values of indices (Ra, Rf i Rg) not all tested lamps are suitable for use on a photo set, as indicated by the value of TLCI index. The lighting requirements on a film set prioritize the quality of color reproduction, even at the expense of reducing the Luminous efficacy of a source (LES ) value. Full Text: PDF ReferencesL.T. Sharpe, A. Jagla, W. Jägle, "A luminous efficiency function, V*(λ), for daylight adaptation", J. Vision 5(11), 948 (2012) DirectLink K. Mangold, J.A. Shaw, M. Vollmer, The physics of near-infrared photography, Eur. J. Phys. 34 (2013), pp. 51-71 CrossRef Simunovic M. P., On Seeing Yellow The Case for, and Against, Short-Wavelength Light-Absorbing Intraocular Lenses, Archives of Ophthalmology, vol. 130, no. 7, pp. 919-926, 2012 CrossRef M. Gilewski, The ecological hazard of artificial lighting in greenhouses, Phot. Lett. Pol., vol. 11 Issue: 3, pp. 87-89, 2019. CrossRef M. Gilewski, The role of light in the plants world, Phot. Lett. Pol., vol. 11, no. 4, pp. 115-117, 2019 CrossRef I. Fryc and E. Czech Spectral correction of the measurement CCD array, Optical Engineering 41(10), pp.2402-2406 (2002). CrossRef L. Bellia, U. Blaszczak, F. Fragliasso, L. Gryko, Matching CIE illuminants to measured spectral power distributions: A method to evaluate non-visual potential of daylight in two European cities, Solar Energy, Volume 208, 2020, Pages 830-858 CrossRef J. Kusznier and W. Wojtkowski, Impact of climatic conditions on PV panels operation in a photovoltaic power plant, IEEE, 2019 15th Selected Issues of Electrical Engineering and Electronics (WZEE), Zakopane, Poland, pp. 1-6, 2019 CrossRef J. Kusznier and W. Wojtkowski, Impact of climatic conditions and solar exposure on the aging of PV panels, IEEE, 2019 15th Selected Issues of Electrical Engineering and Electronics (WZEE), Zakopane, Poland, pp. 1-6, 2019 CrossRef J. Fan, Y. Li, I. Fryc, C. Qian, X. Fan and G. Zhang, Machine-Learning Assisted Prediction of Spectral Power Distribution for Full-Spectrum White Light-Emitting Diode, in IEEE Photonics Journal, vol. 12, no. 1, pp. 1-18, Feb. 2020, Art no. 8200218, CrossRef M. Gilewski, L. Gryko, A. Zajac, Digital controlling system to the set of high power LEDs, Proc. of SPIE, 8902, 89021D, 2013 CrossRef J. Kusznier, W. Wojtkowski, Spectral properties of smart LED lamps, Phot. Lett. Pol., vol. 12, no. 1, pp. 16-18, 2020. CrossRef J. Kusznier, Changes in the Spectral Power Distribution of Light Sources for Smart Lighting, IEEE, 14th WZEE, pp. 1-5, 2018 CrossRef H. F. Ivey, Color and Efficiency of Luminescent Light Sources, J. Opt. Soc. Am. 53, 1185-1198 (1963) CrossRef F. Zhang, H. Xu, Z. Wang, Optimizing spectral compositions of multichannel LED light sources by IES color fidelity index and luminous efficacy of radiation, Appl. Opt. 56, 1962-1971 (2017) CrossRef T. W. Murphy Jr., Maximum spectral luminous efficacy of white light, Journal of Applied Physics 111, 104909 (2012) CrossRef Po-Chieh Hung and Jeffrey Y. Tsao, Maximum White Luminous Efficacy of Radiation Versus Color Rendering Index and Color Temperature: Exact Results and a Useful Analytic Expression, J. Display Technol. 9, 405-412 (2013) CrossRef V. M. Lisitsyn, V. S. Lukash, S. A. Stepanov, and Ju Yangyang , White LEDs with limit luminous efficacy, AIP Conference Proc 1698, 060008 (2016) CrossRef J. Kowalska, I. Fryc, Colour rendition quality of typical fluorescent lamps determined by CIE Colour Fidelity Index and Colour Rendering Index, Przeglad Elektrotechniczny R. 95(7), pp. 94-97, 2019 CrossRef I. Fryc, J. Fryc, A. Wasowski, "Rozważania o jakości oddawania barw źródeł światła, wyrażanej wskaźnikiem Ra (CRI), uwzględniające fizjologię widzenia oraz zagadnienia techniczno-prawne", Przeglad Elektrotechniczny R. 92(2), 218 (2016) CrossRef TECH 3353, Development of a "standard" television camera model implemented in the TLCI-2012, Source: FTV-LED, EBU, Geneva November 2012 DirectLink TECH 3354, Comparison of CIE colour metrics for use in the television lighting consistency index (TLCI-2012), Source: FTV-LED, EBU, Geneva November 2012 DirectLink TECH 3355, Method for the assessment of the colorimetric properties of luminaires the television lighting consistency index (TLCI-2012) and the television luminaire matching factor (TLMF-2013), Source: FTV-LED Geneva March 2017 DirectLink J. Kusznier, Mixing colours inside the optical fibre elements, Przeglad Elektrotechniczny, R 84(8), pp 182-185, 2008 DirectLink

LIGHT SCANNING ON EXTERNAL SLEEVE DISCHARGE IN HALOGENS

1965 ◽  
Vol 43 (5) ◽  
pp. 872-882 ◽  
Author(s):  
M. Venugopalan
Keyword(s):  
Discharge Tube ◽  
Discharge Current ◽  
Applied Field ◽  
Scattered Light ◽  
Maximum Magnitude ◽  
Discharge Column ◽  
Electrode Region ◽  
High Tension ◽  
Discharge Tubes ◽  
Small Rise

It has been verified that the Joshi effect (the photovariation, enhancement +Δi, and diminution −Δi of the discharge current i) in halogen-filled discharge tubes, excited by a transformer discharge of 50-cycle potentials using external sleeve electrodes, is associated with the electrode regions and predominantly with the high-tension (HT) electrode region. The techniques of (i) partial irradiation and (ii) varying the irradiated length of the discharge column starting from either electrode were used and the Joshi effect was observed with (i) a reflection galvanometer and (ii) a cathode-ray oscillograph. The effect of scattered light from the illuminated glass side of the discharge tube and the gas or vapor reaching either electrode was minimized by increasing the spacing of the electrodes and using low gas pressures.It has also been verified that the applied field is one of the factors that determine the magnitude and sign of the Joshi effect. The maximum magnitude of +Δi was observed at the breakdown value (in the dark) of the applied field; the reversal in sign of Δi and maximum magnitude of −Δi were attained by only a small rise in the applied field above that required for the breakdown of the system in the dark.

Analysis of Characteristics of Halogen and LED Automobile Lamps

2020 ◽  
pp. 57-62
Author(s):  
Olga Yu. Kovalenko ◽  
Yulia A. Zhuravlyova
Keyword(s):  
Power Consumption ◽  
Flip Chip ◽  
Weather Conditions ◽  
Luminous Flux ◽  
Luminous Efficacy ◽  
Colour Temperature ◽  
Study Results ◽  
Calculation Results ◽  
Mandatory Rules ◽  
Halogen Lamps

This work contains analysis of characteristics of automobile lamps by Philips, KOITO, ETI flip chip LEDs, Osram, General Electric (GE), Gtinthebox, OSLAMPledbulbs with H1, H4, H7, H11 caps: luminous flux, luminous efficacy, correlated colour temperature. Characteristics of the studied samples are analysed before the operation of the lamps. The analysis of the calculation results allows us to make a conclusion that the values of correlated colour temperature of halogen lamps are close to the parameters declared by manufacturers. The analysis of the study results has shown that, based on actual values of correlated colour temperature, it is not advisable to use LED lamps in unfavourable weather conditions (such as rain, fog, snow). The results of the study demonstrate that there is a slight dispersion of actual values of luminous flux of halogen lamps by different manufacturers. Maximum variation between values of luminous flux of different lamps does not exceed 14 %. The analysis of the measurement results has shown that actual values of luminous flux of all halogen lamps comply with the mandatory rules specified in the UN/ECE Regulation No. 37 and luminous flux of LED lamps exceeds maximum allowable value by more than 8 %. Luminous efficacy of LED lamps is higher than that of halogen lamps: more than 82 lm/W and lower power consumption. The results of the measurements have shown that power consumption of a LED automobile lamp is lower than that of similar halogen lamps by 3 times and their luminous efficacy is higher by 5 times.

Model of multicomponent narrow-band periodical non-stationary random signal

2020 ◽  
Vol 2020 (48) ◽  
pp. 17-24
Author(s):  
I.M. Javorskyj ◽  
◽  
R.M. Yuzefovych ◽  
P.R. Kurapov ◽  
◽  
...  
Keyword(s):  
Time Series ◽  
Real Time ◽  
Hilbert Transform ◽  
Spectral Properties ◽  
Narrow Band ◽  
Analytic Signal ◽  
Random Signal ◽  
Hilbert Transformation ◽  
The Hilbert Transform

The correlation and spectral properties of a multicomponent narrowband periodical non-stationary random signal (PNRS) and its Hilbert transformation are considered. It is shown that multicomponent narrowband PNRS differ from the monocomponent signal. This difference is caused by correlation of the quadratures for the different carrier harmonics. Such features of the analytic signal must be taken into account when we use the Hilbert transform for the analysis of real time series.

Structure and Spectral Properties of New Composites Based on Metal Alkanoates with Gold Nanoparticles

2015 ◽  
Vol 60 (04) ◽  
pp. 356-361 ◽  
Author(s):  
A. Tolochko ◽  
◽  
P. Teselko ◽  
A. Lyashchova ◽  
D. Fedorenko ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Spectral Properties
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