Steady state pressure

Mathews and Kruh , in similar experiments, were unable to obtain steady-state pressures, but this was probably due to the larger size of vessel used, to temperature gradients, and to difficulties due to creeping of the fused sodium hydroxide up the vessel walls. 

During the third phase, the motor chamber continues to fill with propellant combustion products until the steady-state pressure has been reached. The chamber-pressure transient during this phase is described by... 

Solid rocket proplnts, being required to function under steady-state pressure conditions much lower than the max pressure under which artillery proplnts burn, have max burning rates correspondingly lower than those of artillery proplnts(Ref 21a)... 

Both reactions were studied by Brittain, Lau, Knittel, and Hildenbrand102 using a torsion-effusion method in the temperature range 800 to 900 K. They found the S03 pressure over both the sulfate and oxysulfate derived from extrapolation of steady-state pressures to the zero orifice area to be a factor of five lower than those calculated from established thermodynamic data. This indicates that the products are formed in a finely divided metastable state. 

Ns P P number of adsorption sites per unit area of surface, total pressure. steady state pressure in a flow system when atomisation is taking place. 

Po steady state pressure in a flow system in the absence of atomisation. 

This equation describes the steady state pressure difference induced by a temperature difference. 

Both the previous approaches apply to discontinuous GAS process (in which the pressure progressively increases) and indicate precipitation process pressures between 50 and 70 bar, i.e., under subcritical conditions (even when the critical pressure of pure CO2 is considered), whereas the experimental evidences for semi-con-tinuous SAS (steady-state pressure) indicate larger pressure values for the precipitation of micro- and nano-particles."... 

Brewer and Westhaver suggest that p may be considerably larger than p in the same apparatus. On the other hand Henry describes the decomposition as not occurring in the gas, and only on the refrigerated tube surfaces when the pressure is close to the steady-state pressure. He found that the rate decomposition of ozone on the wall of a discharge tube is very sensitive to the state of the surface his observations are consistent with those of other investigators working with un-ionized gas (57). 

Consider a methodological Id-problem of the flow in a duct to ensure that this problem is well-posed. Assume that such a two-speed droplet EPR has been symmetrically placed near both walls of the infinite duct. The steady-state pressure-driven flow in such a duct is governed by the following boundary-value problem for the internal flow ... 

Problem 3-4. Pressure-Driven Flow in a Rectangular Tube. Obtain the solution for steady-state pressure-driven flow in a rectangular conduit of width 2b in the x direction and 2a in the y direction. Plot the velocity averaged over they direction as a function ofx for b/a = 10. It is the tailing off of the velocity near the sidewalls that dominates dispersion for pressure-driven flow in microfluidic channels. (Hint Subtract off the velocity profile... 

This means, as already stated, that an inward force [(r2/r3)(i i 22)] (per unit mass) is necessary to keep the fluid element from undergoing radial motion. The steady-state pressure gradient... 

In the foregoing discussion of the Brownian motion method, the ensemble averages are all constructed from an ensemble of replica systems of the subset of h molecules, the behavior of each replica having been time-smoothed over the interval r. However, in a steady-state transport process dfiN)/dt = 0 at every point in phase space, where f N) is the instantaneous phase density of the N molecules. In principle, at least, it should thus be possible to express the steady-state pressure tensor and the mass and heat currents in terms of ensemble averages constructed without preliminary time-averaging in the replica systems. Thus it is desirable to examine the possibility of obtaining solutions to the reduced Liouville equation, Eq. 8, without preliminary timeaveraging. 

Figure 15. Experimental and model steady-state pressure drop versus liquid velocity. Gas-phase velocity is held constant. Symbols are experimental data solid lines are model predictions. Error bars are shown.

At each setting of the outlet pressure, the steady-state pressure profile and the production rate were measured. Therefore, for each oil, 10—12 flow experiments were conducted. End-point average gas saturations (5 ) were estimated after the flow test at the highest pressure drawdown and are presented in Table II. 

In a closed system, a steady state is established only when the rate of evaporation of the adsorbed layer becomes comparable with the rate of adsorption on the sample. In a flow system, the steady state pressure achieved with the sample adsorbing can be adjusted by altering the flow of gas into the cell. Once a new steady state is reached, VdNj dt = 0. The net rate of adsorption is just equal to the net flow into the cell, and is therefore immediately known, provided the exit speed SE has been previously determined. 

The outside boundaries of the rock mass are assumed to be fixed against normal displacement, and are specified to remain at a constant temperature (12°C). The measured steady state pressure in the rock in the vicinity of the gallery varies between 0 (atmospheric) and less than I MPa. These values are very small to influence the hydraulic response of the bentonite. For the sake of simplicity, we assumed that the outside boundary of the rock mass is maintained at a constant pressure of 0 MPa. The heaters are not explicitly represented instead, the boundaries between the heaters and the bentonite are assumed to be fixed at zero normal displacement and zero fluid flux (very rigid and impermeable heaters), and an imposed power output is specified at either a constant rate or... 

The tank in Example 3.5 has a leak which admits air at the rate of 10 Ibm/min whenever the pressure is less than atmospheric pressure. Ever5 hing else is the same as in Example 3.5. How long does it take the pump to reduce the tank pressure from 1 to 0.01 atm What is the steady-state pressure in the tank ... 

A vacuum chamber has a volume of 10 ft When e vacuum pump is running, the steady-state pressure in the chamber is 0.1 Ibf/in. The pump is shut off, and the following pressure-time data are observed ... 

The mean residence time t of the gas and vapor products in the reactor can be defined as the ratio between the reactor volume V and the volumetric feed rate vo of the gases and vapours flowing through the reactor under steady state pressure conditions. 

Present technology permits experimentation at steady-state pressures of up to about 400,000 atm [ ]. By such techniques, workers have converted graphite into diamond, studied the miscibility of quartz and water, produced metallic sulfur, and performed many other just as exciting experiments. The solid state phase transition of feldspar into jade, which occurs at very near the temperature and pressure conditions at the Mohorovicic Discontinuity, has been cited in discussions of the famous Mohole Project. 

The autoregulating Windkessel was found to accurately reproduce the experimental flow step response of both vascular beds and the systemic circulation. The model further provided the steady-state pressure-flow autoregulation curve, in Hnearized form. The impedance spectrum was predicted to differ from that of the three element Windkessel for frequencies below the heart rate. For frequencies near zero, the impedance approached the slope of the pressure-flow autoregulation curve, as opposed to peripheral... 

Van Huis, G.A., Sipkema, R, and Westerhof, N. 1985. Instantaneous and steady-state pressure-flow relations of the coronary system in the canine beating heart. Card. Res. 19 121—131. 

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