Helium normalisation

Fig. 14.14 The effect of ethanol concentration on the relative SL intensity in argon and helium saturated water normalised with respect to pure water) at 363 kHz [60]...

Fig. 11.6 shows the noncoplanar-symmetric differential cross sections at 1200 eV for the Is state and the unresolved n=2 states, normalised to theory for the low-momentum Is points. Here the structure amplitude is calculated from the overlap of a converged configuration-interaction representation of helium (McCarthy and Mitroy, 1986) with the observed helium ion state. The distorted-wave impulse approximation describes the Is momentum profile accurately. The summed n=2 profile does not have the shape expected on the basis of the weak-coupling approximation (long-dashed curve). Its shape and magnitude are given quite well by... 

Fig. 11.6. The 1200 eV noncoplanar-symmetric momentum profiles for the ground-state (n = 1) and summed n = 2 transitions in helium (Cook et al., 1984). Curves indicated DWIA, distorted-wave impulse approximation PWIA, plane-wave impulse approximation. The curves are calculated using a converged configuration-interaction expansion (McCarthy and Mitroy, 1986) for the helium ground state. The long-dashed curve is the distorted-wave impulse approximation for the Hartree—Fock ground state. Experimental data are normalised to the Is curve at low momentum. From McCarthy and Weigold (1991).

For the operation of the cold model ambient air was chosen as fluidising gas for the riser, and in order to match the required density ratio the gasifier was fluidized with a gas mixture of 55 45 % helium to air. Sj erical bronze particles with a density of 8900 kg/m and a mean particle diameter of 180 pm were chosen as bed material. The geometric scale factor between the two units was five and the normalised particle size distributions of the bronze particles and the sand used on the plant were comparable. The one scaling parameter it was not found possible to match was the particle shape factor 4). In the cold model the particles were spherical (( p1) w4iereas sand particles are normally considered to be broken solids for which ( 0.63 (6) in option in the CFB however attrition will be likely to increase this to nearer unity. 

Range and (in italics) mean of total helium concentrations (He) and neon-normalised helium concentrations (Hon) in overburden gas over mineralised zones and background areas in Australia (from Butt and Gole 1984, 1985). 

The helium leakage value was tested on the half cells in the oxidized state before the coating of cathode. Helium is suitable to be used as the test gas because its molecular is smaller than all the gases under the operation condition of SOFC cells. The helium flowed through the half cell at a pressure difference of 1000 hPa. The shown values in this test were normalised to the measurement area and to a pressure difference of 100 hPa, which was typical for an SOFC stack. One large squared area of 16cm was measured per cell. The leak rate value of samples without polymeric sol-gel layers was around 5-10" (hPa dmV(s cm ). By applying a polymeric sol-gel layer on top of the colloidal-sol-derived intermediate layers, the leak rate value of samples was improved to 1.5-10 (hPa dm ( s cm ). 

Figure 2.1 shows the normal modes for the relaxation of para-H2 by helium at 500 K, calculated from the best available theoretical cross-section data [81.M2]. The left-hand panel shows an initial distribution (in this case, for 3(X) K), and the right-hand panel is the equilibrium distribution at 5(X)K, (Mo),=(So)((So)< the individual populations are displayed horizontally. The other modes are displayed in order of their rate constants, with the fastest ones to the left the elements of each mode are normalised to unity, but the overall sign is arbitrary. The fastest mode M9 corresponds to the transfer of molecules between J=0 and J=2 of i =0 and the next one Mg is the analogous process for p=l. In the relaxation shown here, there is a rather small flux for Mg, given by equation (2.19) physically, this is because this mode does not connect the initial distribution with the final distribution. Then come another pair of processes connecting the J=0, 2, and 4 levels of y = l, and then of r=2, followed by a series of other rotational processes of t)=0 involving... 

Fig. 5.25 Normalised estimates of first-order contributions to the overall variance of predicted butane mole fraction at 750 K calculated using first-order local sensitivities (grey) and the global HDMR method (black). Both are derived from a model describing the oxidation of n-butane in a jet stirred reactor (residence time of 6 s, atmospheric pressure, stoichiometric mixtures containing 4 % (mol) -butane diluted in helium). EXGAS notation is used. Adapted with permission from Cord et al. (2012). Copyright (2012) American Chemical Society...

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