Solid-gas coupling

Solid-gas coupled model for the gas leak flow system... 

The SIP methods by Stone (1986) for the gas leak flow equations and the rock mass deformation equations for double parallel coal seams have been developed by Sun (1998,2002) with Microsoft Visual C+-I- 6.0 under Windows2000 on a Pentium rv rc. The program is suitable for isotropic heterogeneous coal seams with irregular shapes as well as anisotropic heterogeneous coal seams. The systems with the first or the second boundary conditions as well as the hybrid boundary conditions can all be solved. The overview of the numerical implementations of the SIP methods for the solid-gas coupled mathematical model for double parallel coal seams is described as follows. 

Peide Sun, Xuefu Xian. 1998. Solid-gas coupled analysis for safety range of upper protective layer mining. Chinese Journal of Rock Mechanics Engineering. 17(supp) 932-936 (in Chinese with English abstract). 

Xu T. 2004. Solid gas coupling numerical test of Coal and rock failure process[D]. Shenyang Doctoral Dissertation of Northeastern University. 

Yi G.Z., Wang D.K., Zhang D.M. 2008. Research on solid gas coupling dynamic model and simulation of coal contain gas. Chinese Journal of geotechnical engineering. 30(10) 1430-1436. 

Zhao, J.-J., Duan, Y.-Y., Wang, X.-D., and Wang, B.-X. (2012) Effects of solid-gas coupling and pore and particle microstructures on the effective gaseous thermal conductivity in aerogels. /. Nanopart. Res., 14 1024, 1-15. 

The solid state coupling of formamide - 2.3 MHz S7) — is still smaller and very different from the gas value 58) — 3.6 MHz — the latter is close to that of urea. The difference between the solid state and gas couplings of formamide is probably due to intermolecular contributions, particularly hydrogen bonding, whose existence is established by the high boiling point and by the dielectric properties 59) of this compound. It may be seen that, if c is decreased, the coupling becomes smaller and the asymmetry increases, as is effectively observed. 

The continuity equations for mass and energy were used to derive an adiabatic dynamic plug flow simulation model for a moving bed coal gasifier. The resulting set of hyperbolic partial differential equations represented a split boundary-value problem. The inherent numerical stiffness of the coupled gas-solids equations was handled by removing the time derivative from the gas stream equations. This converted the dynamic model to a set of partial differential equations for the solids stream coupled to a set of ordinary differential equations for the gas stream. 

Figure 10.10. Scheme of the process occurring In the gas-coupled ultrasonic spectroscopy of gas-solid systems. (Reproduced with permission of Elsevier, Ref [125].)... 

In general, fluidized beds are of special interest when a high degree of gas to solid contact coupled with large throughput of gas at fairly low pressure drop is needed. 

Keywords quantitative, solid diazonium salt, pyrazolopyridine, azo coupling, solid-solid reaction, solid-solid reaction, solid-gas reaction, cascade reaction... 

Lepinasse E, Spinner B (1994), Cold production through coupling of solid-gas reactors I Performance analysis , Int. J. Refrig., 17(5), 309-322. 

In principle, the ultrasonic techniques described for solid-liquid flow measurement can be applied to measure air flow rate and particle velocity. Direct measurement of air flow rate by measuring upstream and downstream transit times has been demonstrated. But, the Doppler and cross-correlation techniques have never been applied to solid/gas flow because the attenuation of ultrasound in the air is high. Recent developments have shown that high-frequency (0.5-MHz) air-coupled transducers can be built and 0.5-MI Iz ultrasound can be transmitted through air for a distance of at least 1 in. Thus, the cross-correlation technique should be applicable to monitoring of solid/gas flow. Here, we present a new cross-correlation technique that does not require transmission of ultrasonic waves through the solid/gas flow. The new technique detects chiefly the noise that interacts with the acoustic field established within the pipe wall. Because noise may be related to particle concentration, as we discussed earlier, the noise-modulated sound field in the pipe wall may contain flow information that is related to the variation in particle concentration. Therefore, crosscorrelation of the noise modulation may yield a velocity-dependent correlation function. 

Fig. 10.8. Temperature variation of the magnetic susceptibility (a) and the effective magnetic moment (b) for a heterospin system SA = 1/2 and = 1 gA = 2.0, gB = 2.0, solid— antiferromagnetic coupling (J/k = —100 K) dashed—ferromagnetic coupling (J/k — +100 K).

In this paper, a mathematical model for coupled coal/rock mass deformations and gas leak flow in parallel coal seams is presented from a new viewpoint of solid-gas interaction. It consists of equations for the gas leak flow, equations for coal/rock mass deformation and the... 

The main transport parameters to be estimated are the mass transfer coefficients (gas-liquid (liquid side) fc , gas-liquid (gas side) kg, and liquid-solid fc )). Coupled to that is the estimation of the interfacial area per unit volume a, and often it is the combination (i.e., kia or kgO) that is estimated in a certain experimental procedure. Thermodynamic parameters, such as Henry s law constant (fZ) can be estimated in a simpler manner since their estimation on the flow or on any time-dependent phenomenon. Mass transfer coefticients may be evaluated in well-defined geometries with known flow fields using classical theories like film theory, penetration theory, surface renewal... 

It is clear that McMurry reactions can be performed with low-valent titanium species in various oxidation states. Pinacol and alkene-forming reductive coupling reactions have been achieved with organometallic complexes of Ti(0), Ti(II), and Ti(III) (see Section 6.2.2.3). While no evidence was found for the presence of 11(0) on reduced Ti02 surfaces active in benzaldehyde coupling, X-ray photoelectron spectroscopy showed that the active site required for gas-solid reductive coupling is an ensemble of Ti cations in the +1, +2, and +3 oxidation states that collectively effect the four-electron reduction [258]. 

This coupling can be used for characterization of acidic or basic character of solid catalysts, and for study of solid-gas reactions. Systems used for these measurements are usually modified DSC instruments connected with GC/MS by a heated capillary tube [28-32]. In a typical experiment small pulses of probe gas are injected at regular intervals in to the carrier gas stream from a gas sampling valve. The gas flows are regulated by mass flow controllers. The concentration of ammonia down-stream of the sample is monitored with the GC/MS and heat evolution with the calorimeter. 

THE PHOTOACOUSTIC effect is based on the conversion of absorbed light energy into heat by means of radiationless deexcitation processes. On irradiation of a solid or liquid sample by intensity modulated light, a heat wave of the same frequency is generated in the sample. The heat wave is transferred by diffusion to the surface of the sample, where oscillatory thermal effects are generated in the coupled gas. These can be detected as an acoustic signal. This technique is known as gas-coupled photoacoustic spectroscopy. 

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