Corona model

Typical results of such models are effective rate coefficients which depend not only on Te but also on ne and the vibrational population in the ground state. The importance of the vibrational population on some effective rate coefficients can be seen in Fig. 4.5. Especially for low Te, the enhancement can exceed one order of magnitude. Details of the calculation of vibrational populations are described in Sect. 4.4.1. For the analysis of radiation it is very convenient to apply the aforementioned corona model formula in which the pure excitation rate coefficient is replaced by the effective rate coefficient. 

The data from the SANS study were fitted to a poly-disperse spherical core-plus-shell (or corona) model assuming no intermicellar interactions. The model Sharma and Bhatia used essentially fits three parameters, namely the radius of the micelle core, / i, the radius of the micelle shell, R2 and the micelle aggregation number. To fit the SANS data to the model, the authors assumed that the micellar cores were comprised only of hydrophobe (PPO) and D2O, while the shell was assumed to comprise only of hydrophile (PEO) and D2O, with no intermixing of the PPO and PEO chains. 

Figure 5.2 Sectional view of vapour-pres sure osmometer Corona model 117 (1) thermistor (2) pipe for dropping in solution and solvent (3) reservoir (4) gasket ring (5) filter paper (6) inside cap (7) cap of filter paper (8) outside cap (9) pipe holder (10) lead wire (11) pipe for circulating water (12) insulator. Reprinted from ref. 5 by permission of Pergamon Press pic.

Figure 5.2 shows a schematic sectional view of the chamber of the Corona model 117 [15]. 

Except for the Corona model 117, two carefully matched thermistors, on which the solution and solvent drops are placed, are installed in a chamber saturated with solvent vapour. The temperature difference (T-Tq) is detected as a change in the resistance of the thermistors. A large factor governing the accuracy of the temperature measurement of the drops by the thermistors in VPO is the unmatched resistance of the thermistor bead-temperature relations between two thermistors. Even if an aged and well-matched pair of thermistors are chosen at a specific temperature, these do not always match at a different temperature. That is, even if the temperature of the surroundings fluctuates only to a small extent, the conventional Wheatstone bridge is kept in a balanced state only when [14]... 

The Corona model 117 is based on the principle established by Kamide et al. [14], who constructed a modified version of the sol vent-vapour chamber and thermistor assembly of Dohner et al. [15], and installed them in a Hitachi model 115 to obtain a new prototype VPO apparatus with increased sensitivity. With the conventional Wheatstone bridge circuit modified by introducing a matching circuit that has two precision variable resistors, the measurements can be made at any desired temperature without changing the thermistors. This enables a temperature difference of about 6x 10" °C to be detected. 

Using the prototype of the Corona model 117 VPO, the calibration parameter Ks of solutions of unbranched alkanes, such as octadecane, and tris-tearin in various solvents, such as Ai-hexane and w-octane, was determined from the intercept of the graph of (T-To)sic against c through the relation [14] ... 

Fig. 8. Diffraction space according to the "disordered stacking model" (a) achiral (zigzag) tube (b) chiral tube. The parallel circles represent the inner rims of diffuse coronae, generated by streaked reflexions. The oo.l nodes generate sharp circles. In (a) two symmetry related 10.0 type nodes generate one circle. In the chiral case (b) each node generates a separate corona [9].

Fig. 13. Simulated diffraction space of a 10-layer monochiral MWCNT with Hamada indices (40+8/ , 5+k) with / =0,...,9. In (a), (a ) and (02) the initial stacking at ( q was ABAB. whereas in (b), (b[) and (b2) the initial stacking was random, (a) The normal incidence pattern has a centre of symmetry only. (3 )(a2) The cusps are of two different types. The arc length separating the cusps is c (b) The normal incidence pattern now exhibits 2mm symmetry. (b )(b2) The cusps are distributed at random along the generating circles of the evolutes. These sections represent the diffuse coronae referred to in the "disordered stacking model" [17].

A Del Electronics, Model ESP-100A, electrostatic precipitator was used for sample collection. Cigarette smoke particles were found to give approx the same particle distribution pattern on the collection filter paper as the gunshot residue, and since the smoke stains the paper, this provided a v rapid technique for optimizing operation conditions. With a flow rate of 15cfm and a corona current of 125 uA, the residue collects primarily on a narrow band across the sample paper. Samples were collected on Whatman No 1541 filter paper which lined the inside of the sample collection tube. The presence of this paper allowed air to flow only thru the center of the tube, so particle collection was made upon the filter paper exclusively. The filter paper samples were pelletized prior to neutron activation analysis... 

Heller and Tabibian (13) noted that errors, due to laterally scattered light and the corona effect, as large as to cause a 30 reduction in measured turbidity, may result if instruments which are perfectly suitable for ordinary absorption measurements are used for turbidity measurements without proper modifications. To evaluate the performance of our turbidity detector, particle suspensions of various concentrations of several polystyrene latex standards were prepared. Their extinction coefficients were measured using both a bench-top UV spectrophotometer (Beckman, Model 25) and the online detector (Pharmacia). 

The gas mixture containing the nitrogen oxides is very important as well. Experiments and modeling carried out for N2/NOx mixtures, or with addition of 02, H20, C02 and hydrocarbons will be discussed. Typical hydrocarbon additives investigated are ethane, propene, propane, 2-propene-l-ol, 2-propanol, etc. As compared to the case without hydrocarbons, NO oxidation occurs much faster when hydrocarbons are present. The reaction paths for NO removal change significantly, in fact the chemical mechanism itself is completely different from that of without hydrocarbon additives. Another additive investigated extensively is ammonia, used especially in corona radical shower systems. 

Zhao et al. [74] developed a kinetic model to analyze the removal of nitrogen oxides in a pulsed corona discharge in NO/N2 mixtures. They considered reactions of NO and N02 with N and O atoms and with excited N2(A3S) molecules. 

Eichwald, O., Guntoro, N.A., Yousfi, M. et cd. (2002) Chemical kinetics with electrical and gas dynamics modelization for NOx removal in an air corona discharge,./. Phys. D Appl. Phys. 35, 439-50. 

Fig. 3.34 Normalized intermediate dynamic structure factor for the corona of a PS-PI diblock = 8.5 kg mol-1, 12% PS) in deuterated decane (2% polymer). Different symbols correspond to measurements at r//10AH = ( ) 26, (V) 32, ( ) 38, (X) 51, (O) 64, (A) 89, (O) 115. Solid lines correspond to a model described by Farago el al. (1993).

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