scholarly journals Cathode Region of a Steady-state Townsend Discharge in Nitrogen

1989 ◽  
Vol 42 (4) ◽  
pp. 365 ◽  
Author(s):  
LJ Kelly ◽  
MJ Brennan ◽  
AB Wedding
Keyword(s):  
Steady State ◽  
Molecular Nitrogen ◽  
Cathode Region ◽  
Spatial Variations ◽  
Photon Flux ◽  
Rare Gas ◽  
Gas Discharges ◽  
Townsend Discharge

The photon flux technique has been used to study the cathode region of a steady-state Townsend discharge. Spatial variations in the radiation emitted from the C3fIu and B2.r~ states of molecular nitrogen were etected in the vicinity of the cathode for EIN"" 331 and 555 Td. In particular, the second positive emission at 337�1 nm is similar to the Holst-Oosterhuis layers observed in rare gas discharges.

scholarly journals A Tomographic Investigation of Variations in the Excited State Populations of E x B Discharges

1990 ◽  
Vol 43 (6) ◽  
pp. 779 ◽  
Author(s):  
AM Garvie ◽  
MJ Brennan
Keyword(s):  
Spatial Distribution ◽  
Excited States ◽  
Molecular Nitrogen ◽  
Electronic States ◽  
Photon Flux ◽  
Model Simulations ◽  
Townsend Discharge ◽  
Threshold Energies ◽  
Reconstructive Tomography ◽  
Made In

A comparison of the spatial distribution of emissions from two molecular nitrogen electronic states of markedly different threshold energies has been made in a non self-sustained Townsend discharge in an ExB field. The spatial mapping has been performed using a combination of the 'photon flux' technique and reconstructive tomography. Observed differences in the spatial distribution of the two excited states are interpreted in terms of the gradient expansion of the energy distribution function. Comparisons made with the results of two-model simulations confirm this interpretation.

scholarly journals Observation of Spatial Variations in the Energy Distribution Function for Steady-state Townsend Discharges

1989 ◽  
Vol 42 (1) ◽  
pp. 101 ◽  
Author(s):  
AB Wedding ◽  
LJ Kelly
Keyword(s):  
Distribution Function ◽  
Energy Distribution ◽  
Spatial Dependence ◽  
Molecular Nitrogen ◽  
Electronic States ◽  
Spatial Variations ◽  
Energy Distribution Function ◽  
Electron Production ◽  
Townsend Discharge ◽  
Relative Excitation

Spatial variations of the relative excitation rates for two electronic states of molecular nitrogen have been measured for a point source Townsend discharge. The ratio of these rates shows a spatial dependence which is explained in terms of an electron con,centration gradient expansion of the energy distribution function. The electronic states were chosen to have quite different thre hold energies such that the ratio would be sensitive to small changes in the electron energy distribution. A model for secondary electron production is used to explain the significant influence of secondary ectrons in the outer regions of the discharge.

On the excitation of CCl(A 2δ) in CCl4 and CCl4/rare gas discharges

1987 ◽  
Vol 135 (4-5) ◽  
pp. 435-440 ◽  
Author(s):  
F.-W. Breitbarth ◽  
D. Berg ◽  
H.-J. Tiller
Keyword(s):  
Rare Gas ◽  
Gas Discharges

Phosphate Requirement, Photosynthesis, and Diel Cell Cycle of Scenedesmus obliquas Under Fluctuating Light

1987 ◽  
Vol 44 (10) ◽  
pp. 1753-1758 ◽  
Author(s):  
C. N. Shin ◽  
G-Y Rhee ◽  
J. Chen
Keyword(s):  
Steady State ◽  
Average Rate ◽  
Scenedesmus Obliquus ◽  
Constant Light ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Cell Numbers ◽  
P Limitation ◽  
Fluctuating Light ◽  
Light Fluctuation

The effect of light fluctuation (0.06 Hz) on P requirement, photosynthesis, and the diel cell-division cycle was investigated in Scenedesmus obliquus in a chemostat under a 12 h day: 12 h night cycle. P requirement was much less under oscillating than under constant daylight of the same photon flux density. However, cell chlorophyll a was significantly higher, indicating an increased N requirement. There was little difference in photosynthetic efficiency (the slope of the photosynthesis–light regression) between oscillating and constant light, but photosynthetic capacity was higher in fluctuating light. Cell C was also higher. A strong diel rhythmicity in steady-state cell numbers was observed with little phase difference between oscillating and constant light. Although steady-state cell numbers under P limitation were significantly higher under fluctuating light, there was no difference in instantaneous growth rates and their diel distribution. At a dilution rate of 0.6∙d−1, cell death occurred at an average rate of −0.56∙d−1 between 4 h before and 5 h after the onset of the dark period.

scholarly journals ENGINEERING FOR MICROPROPAGATION OF SUGARCANE

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 618b-618
Author(s):  
Paul N. Walker ◽  
Joan P. Harris ◽  
Loren D. Gautz
Keyword(s):  
Linear Programming ◽  
Steady State ◽  
Programming Model ◽  
Cost Model ◽  
Photon Flux ◽  
Unsteady State ◽  
Photosynthetic Photon Flux ◽  
Engineering Studies ◽  
State Production ◽  
The Cost

Four engineering studies on optimization of sugarcane micropropagation are summarized. The optimum environmental conditions based on the cost of production were found to be with two medium changes per multiplication period, 6 initial shoots per vessel and a photosynthetic photon flux of 200 μmol/m2s even though greater production was obtained for more light, fewer shoots per vessel and more medium changes. A cost model for comparing production treatments under steady state production and a linear programming model for unsteady state production are discussed. Preliminary results on mechanization of the transfer process are also presented.

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