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.

The role of resonance radiation in the propagation of a positive pre-breakdown ionization wave in long discharge tubes

2021 ◽  
Author(s):  
Aleksei V Siasko ◽  
Yuri B Golubovskii ◽  
Sergei Valin
Keyword(s):  
Discharge Tube ◽  
Tube Wall ◽  
Finite Size ◽  
Ionization Wave ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Radiation Trapping ◽  
Discharge Tubes ◽  
Electron Photoemission

Abstract The work is devoted to calculating the flux of resonance photons towards the boundary of a cylindrical discharge tube of a finite size during the propagation of a pre-breakdown ionization wave of positive polarity. A cylindrical discharge tube of finite dimensions with argon at the pressure of p=1 Torr is considered. The propagation mechanisms of metastable and resonance atoms are compared. For the considered discharge conditions, the space-time distributions of metastable and resonance atoms are calculated. The manuscript presents a technique for calculating the flux of resonance photons onto the discharge tube wall with the account of the radiation trapping. It is shown that for the studied conditions the photon flux density towards the longitudinal boundary of the tube ahead of the ionization wave can reach 1013 cm-2s-1. The obtained results allow describing the appearance of seed electrons ahead of the positive ionization wavefront during its propagation due to the electron photoemission from the discharge tube wall.

Improving Sound Rating of the Out Door Unit by Modifying Discharge Tube Design

2007 ◽  
Author(s):  
Parag H. Mathuria ◽  
Macinissa Me´zache
Keyword(s):  
Discharge Tube ◽  
Air Conditioning ◽  
Power Level ◽  
Sound Power ◽  
Efficiency Ratio ◽  
Air Conditioning System ◽  
Sound Power Level ◽  
Discharge Tubes ◽  
Air Conditioning Systems ◽  
Made In

In today competitive market, Seasonal Energy Efficiency Ratio (SEER) and sound rating of the out door unit of an air conditioning system are strong marketing and selling parameters. Air conditioning systems consist of an indoor unit and an outdoor unit. The sound of the indoor unit is mainly radiated by the blower or fan of the unit. The outdoor unit has three major components, namely, a compressor, a condenser coil and a fan. In general, the sound power levels produced by the outdoor unit are dominated by the fan, and in some cases, the fan and the compressor. In more recent designs, significant improvement has been made in the sound performance of the fan itself, resulting in a challenge to compressor manufacturers to produce quieter compressors. In this case, compressor-system interaction becomes a serious issue with reference to noise generation. The vibration energy of the compressor is transmitted to the system through the suction and discharge tubes, and the mounting feet. Air conditioning manufacturers are faced with the challenge of eliminating these sources of excitation to improve the sound rating and, more importantly, design better quality products. The main object of the paper is to modify the design of the discharge tube using an experimental iterative approach. A reduction of 2 dB has been achieved in the total sound power level of the system. On the dominant one third octave bands, sound power levels are reduced up to 7 dB. The results of this investigation will serve as the basis for the development of an analytical designed tool for air conditioning system design. These results were validated on four systems.

scholarly journals The spectrum of ionized tellurium—extension of Te III

1937 ◽  
Vol 158 (895) ◽  
pp. 562-570 ◽  
Keyword(s):  
Discharge Tube ◽  
Royal Society ◽  
Quartz Window ◽  
Adequate Supply ◽  
Boiling Points ◽  
Considerable Portion ◽  
Partial Analysis ◽  
Discharge Tubes ◽  
Sufficient Intensity ◽  
Very High

In a former communication* to the Royal Society, a partial analysis of the spectrum of Te III was reported, wherein the terms and the term combinations of the 5 p ,5 d ,and 6 p configurations were recorded. The multiplets in the quartz region, embodying the combinations of the 6 d , sp 3 , and 7 s terms could not be brought out with sufficient intensity on the photographic plates, owing to the difficulty of maintaining an adequate supply of tellurium vapour in the discharge tube. The melting and boiling points of tellurium being very high, the heating necessary for this purpose was so great that discharge tubes made even of pyrex glass were found to collapse during the experiment. In these later experiments, therefore, a discharge tube made of quartz, and of the design indicated in fig. 1, was used. The end A remained closed permanently, a quartz window being fused to it. This facilitated strong heating of a considerable portion of the tube including the capillary, the capillary itself being kept filled with the vapour of tellurium metal by continuous evacuation of the tube throughout the time of the exposure. This device was found to be very effective, the desired multiplets appearing with sufficient intensity on the photographic plates. The instrument used in photographing the spectrum was the Hilger large Littrow type E 1 . The discharge was maintained by a ½-kilowatt transformer, used in conjunction with a condenser of capacity of 0·02 mf. The exposures lasted for two or three hours. Predicted Terms Of the terms in Te III, predicted by Hund’s theory, those due to the 5 p , 5 d ,and 6 p configurations were identified in the previous work. The remaining terms, i. e .,those due to higher configurations only, are given in Table I.

Study of moving striations in plasmas. IV. Electron-energy transfer and the determination of the electron thermal relaxation length

1968 ◽  
Vol 46 (19) ◽  
pp. 2193-2200 ◽  
Author(s):  
Michel G. Drouet
Keyword(s):  
Energy Transfer ◽  
Discharge Tube ◽  
Discharge Current ◽  
Small Amplitude ◽  
Positive Column ◽  
Relative Phase ◽  
Thermal Relaxation ◽  
Plasma Parameters ◽  
Relaxation Length

A general expression relating the small variations of the electron density, the electric field, and the electron temperature in a positive column is derived. It is shown that measurements of the variations of these plasma parameters in moving striations of small amplitude and in particular of the relative phase of these variations can be used to determine the thermal relaxation length for the electrons in a positive column.The value of the electron thermal relaxation length for a positive column in neon, with a pressure of 1 Torr, discharge current 26 mA, discharge-tube diameter 6.5 cm, is found to be approximately 1 cm.

Fabrication and Testing of Applied-Field Magneto Plasma Dynamic Thruster with Argon Propellant

2021 ◽  
Vol 13 (3) ◽  
Author(s):  
C. Akash ◽  
M. Mahavishnc ◽  
E. Manikandan ◽  
M. Manikandan ◽  
K. Vijayaraja
Keyword(s):  
Permanent Magnet ◽  
Discharge Current ◽  
Applied Field ◽  
Specific Impulse ◽  
Space Mission ◽  
Operating Conditions ◽  
Low Thrust ◽  
Plasma Dynamic ◽  
Power Circuit ◽  
High Discharge

The experimental setup of applied-field Magneto Plasma Dynamic Thruster (MPDT) is a form of electrically powered spacecraft propulsion system. The thrusters are used for deep space mission, which consist of long duration, low thrust acceleration and less propellant storage. MPDT uses the force on the charged particle by an electromagnetic field to generate thrust. The technology takes high discharge current for two electrodes and solenoid coil as applied-field. In the present investigation, the high discharge current is replaced by a limited discharge current, it is reduced by the use of capacitors bank to discharge the current for two electrodes. The solenoid coils are replaced by permanent magnet as applied-field to generate the thrust. The basic requirements for MPDT are the power circuit made by capacitors bank of electrolytic type. The electrolytic capacitors are smaller in size and produces limited voltage, which will support limited current flowing between the two electrodes. The material used for anode and cathode are copper and tungsten respectively. A permanent magnet is fixed over the anode coaxially and cathode is placed in center. A propellant will be injected in between the two electrodes. The propellant gas used in this thruster is argon. The performance of the thruster is tested in vacuum condition and the thrust value is measured by a load cell. The prototype of MPDT is tested and measurement of discharge current, thrust, specific impulse and efficiency are carried out. The thrust for various discharge current is measured and the efficient operating conditions of MPDT can be obtained.

Free double layers in mercury-arc discharges

1989 ◽  
Vol 42 (2) ◽  
pp. 321-352 ◽  
Author(s):  
Homero Santiago Maciel ◽  
J. E. Allen
Keyword(s):  
Double Layer ◽  
Discharge Current ◽  
Arc Discharge ◽  
Electrical Energy ◽  
High Energy ◽  
Double Layers ◽  
Electrostatic Energy ◽  
High Current ◽  
Discharge Column ◽  
Current Limitation

A study has been carried out of free double layers formed within the plasma volume of a low-pressure mercury-arc discharge at high current densities. The free double layer is observed to form as a visible boundary, which drifts slowly from the central section of the discharge. Current-driven instabilities are observed as the discharge current is gradually increased to a critical value, at which current limitation is observed to occur. This process, which is accompanied by high-current spikes, ceases when the free double layer becomes visible as a sharp boundary dividing the discharge column into two regions of different luminosities. The layer is observed to form in the later stages of current limitation, the onset of which occurs for a ratio of drift to thermal speed of electrons of about unity. Electrical energy is converted by the layer into kinetic energy of the charged particles. Accordingly, high-energy ions were measured by means of an electrostatic energy analyser. The multiple-sheath character of the free ‘double layer’, which is inferred from probe measurements of potential profiles, is discussed and comparisons with other space-charge structures with the same topology are made.

The Influence of Discharge-Tube Cooling on the Performance of Surface-Wave Plasmas Intended as Element-Specific Detectors for Gas Chromatography

1992 ◽  
Vol 46 (3) ◽  
pp. 430-435 ◽  
Author(s):  
Robert L. A. Sing ◽  
Claude Lauzon ◽  
Khanh Chi Tran ◽  
Joseph Hubert
Keyword(s):  
Gas Chromatography ◽  
Surface Wave ◽  
Wall Thickness ◽  
Discharge Tube ◽  
Emission Spectra ◽  
Water Cooling ◽  
Noise Amplitude ◽  
Incident Power ◽  
Amplitude Spectra ◽  
Discharge Tubes

Direct water cooling of the discharge tube of surfatron-sustained plasmas is implemented. Discharge tubes of 2 mm i.d. × 0.1 mm wall thickness are able to sustain He plasmas at incident power levels up to 500 W for prolonged periods without severe degradation. The emission spectra and noise amplitude spectra of water-cooled plasmas are compared to those for the air-cooled, thick-walled discharge tubes commonly employed. Incident power and tube diameter optimizations are discussed.

scholarly journals The microsporidian spore invasion tube. III. Tube extrusion and assembly.

1982 ◽  
Vol 93 (3) ◽  
pp. 976-979 ◽  
Author(s):  
E Weidner
Keyword(s):  
Discharge Tube ◽  
Polar Filament ◽  
Polar Tube ◽  
Tube Material ◽  
Latex Particles ◽  
Tube Extrusion ◽  
Discharge Tubes ◽  
Microsporidian Spore

The polar filaments within microsporidian spores discharges as tubes with subsecond velocity. Populations of discharging tubes of Glugea hertwigi spores pulse-labeled with latex particles for 1-3 s were consistently devoid of label at the distal ends; discharging tubes were completely labeled after 30- to 60-s exposure to latex. This experiment indicates that discharge tubes grow at the tip. Completely assembled discharge tubes consisted of single, empty cylinders; however, incompletely discharged tubes had a cylinder-within-a-cylinder profile at the distal ends. This observation indicates that the discharge tube material emerges at the distal end by an eversion process. Finally, studies with cinematic Nomarski interference optics of spore tubes extruding across a water-air interphase indicate that all the material emerging from the growing tip of the tube is incorporated into the wall of the discharge tube. Evidence indicates that the polar filament of undischarged spores is a homogeneous coil of polar tube protein equivalent to the polar tube protein in discharged tubes.

DELAYED IMPLOSION OF THE Z-PINCH IN NITROGEN

1963 ◽  
Vol 41 (10) ◽  
pp. 1547-1553
Author(s):  
F. L. Curzon ◽  
R. T. Hodgson ◽  
R. J. Churchill
Keyword(s):  
Discharge Current ◽  
Time Interval ◽  
Electrical Characteristics ◽  
Discharge Column ◽  
Minimum Diameter ◽  
Photographic Evidence ◽  
Z Pinch ◽  
Framing Camera

The paper presents the first photographic evidence of the delayed implosion of the Z-pinch in nitrogen at pressures in excess of 375 μ Hg. Two implosions are observed before the discharge column is compressed to its minimum diameter. The time interval between the two implosions is found to increase linearly with pressure.The radius of the discharge column as a function of time is measured with a framing camera and is also calculated from the electrical characteristics of the discharge. By comparing the computed and measured values of the radius of the discharge column at given pressures, it has been shown that the second implosion does not arise from a transfer of the discharge current into material near the walls of the discharge vessel, in contrast to results commonly observed in very energetic discharges.

ON RECTIFICATION AND DETECTION RECTIFICATION AND POWER PACK DESIGN

1930 ◽  
Vol 2 (2) ◽  
pp. 101-130
Author(s):  
Richard Ruedy
Keyword(s):  
Glow Discharge ◽  
Transmission Lines ◽  
Discharge Tube ◽  
Experimental Methods ◽  
Discharge Tubes ◽  
Vacuum Tubes ◽  
Testing Work

The theory of the mercury arc rectifier is applied to the problem of rectification and detection of alternating currents by vacuum tubes, in radio work, and the meaning of the conventional detector formula is discussed in terms of this theory. For comparison the rectifying action produced in discharge tubes by virtue of their falling characteristic is calculated. The design of filters for smoothing out the rectified current is treated by making use of the results obtained from telephonic transmission lines. By means of the formulæ given for the different cases a comparison can be made between the filters with capacitance input used since 1925, and the type of filters which should be used in order to prevent temporary overloading of the power tubes. The chief experimental methods for testing the theory, and for examining the rectified current, are indicated; the advantages of the glow discharge tube oscillograph are pointed out, and its use in testing work is proposed in place of the methods hitherto followed.

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