Rate experimental

Experimental Determination of the Burning Rate. Experimental determinations of the burning rate are made with the closed tomb for gun propellants and the strand burner for rocket propellants. The closed bomb is essentially a heavy-wahed cylinder capable of withstanding pressures to 689 MPa (100,000 psi). It is equipped with a piezoelectric pressure gauge and the associated apparatus requited to measure the total chamber pressure, which is directly related to the force of the propellant. It also measures the rate of pressure rise as a function of pressure which can then be related to the linear burning rate of the propellant via its geometry. Other devices, such as the Dynagun and the Hi—Low bomb, have also been developed for the measurement of gun propellant performance. 

MeCabe s (1929a,b) AL law states that erystals of the same substanee growing under the same eonditions should grow at the same rate. Experimental evidenee has shown that this law is frequently violated. The growth rate of a erystal faee, for example, and the instantaneous veloeity of steps spreading aeross the surfaee of a erystal have been shown to fluetuate with time, even though external eonditions, e.g. temperature, supersaturation and hydrodynam-ies, remain eonstant. 

Fig. 1. Effect of pumping speed on a desorption peak at a fixed heating rate. Experimental parameters given in the text. Reproduced from Ehrlich (27), with permission.

In the usual case h and hf are falling in the direction of flow and Ah and Ahf are therefore negative. Values of frictional pressure drop, — APtpf may conveniently be correlated in terms of the pressure drop —APL for liquid flowing alone at the same volumetric rate. Experimental results obtained for plug flow in a 25 mm. diameter pipe are given as follows by Richardson and Higson(6) ... 

Figure 3.10 Calculated heat transfer coefficient depending on micro-channel dimensions and water flow rate. Experimental data are given in [47].

Figure 1. Measured conversions and calculated polymerization rates. ( ) experimental values. Solid lines calculated values from equations in Table II.

This equation is similar to that for the ordinary polymerization, indicating that Rp is independent of the concentration of P-N. In fact, the polymerization rate experimentally determined in the presence of P-N agreed with the rate of thermally initiated polymerization without any initiators. The production of the polymer induced a decrease in the Rvalue because of the gel effects, resulting in an increase in the rate. The suppressed gel effects in the presence of TEMPO have also been reported [233]. Catala et al. interpreted the independence of the polymerization rate from the nitroxide concentration with the terms of the association of domant species. However, there is no experimental evidence for the association [229,234,235]. 

A common dimensionless number used to characterize the bubble formation from orifices through a gas chamber is the capacitance number defined as Nc — 4VcgpilnDoPs. For the bubble-formation system with inlet gas provided by nozzle tubes connected to an air compressor, the volume of the gas chamber is negligible, and thus, the dimensionless capacitance number is close to zero. The gas-flow rate through the nozzle would be near constant. For bubble formation under the constant flow rate condition, an increasing flow rate significantly increases the frequency of bubble formation. The initial bubble size also increases with an increase in the flow rate. Experimental results are shown in Fig. 6. Three different nozzle-inlet velocities are used in the air-water experiments. It is clearly seen that at all velocities used for nozzle air injection, bubbles rise in a zigzag path and a spiral motion of the bubbles prevails in air-water experiments. The simulation results on bubble formation and rise behavior conducted in this study closely resemble the experimental results. 

Figure 5.27. Etch rates (experimental and model predictions) for PTFE containing varying dopant concentrations at 248 nm (a) and 308 nm (b). Pulses full width at half-maximum values are 16 and 25 ns for 248- and 308-nm emissions, respectively (from D Couto eta/.78).

NUCLEATION RATE (experimental) x E-06 Figure 8. Comparison of experimental and calculated nucleation rates. 

Experimental radiative decay rates" Experimental photoionization cross sections6 QDT three channel model 6s jj2, 5d5/2 limits"... 

The inhibition by hydrogen was obviously more pronounced in the micro channels. Without hydrogen in the feed, the reaction rate was on average 34% higher for the coated catalysts. The kinetic expression described the reaction rate experimentally observed with an error of < 15% for the packed bed and < 20% for the micro channels (see Figure 2.6) [24]. 

Figures 2-4 show that no experimental data were recorded at low impeller shear rates. Experimental data began at y = 8.53 s4 for 21% solids, 5.15 s 1 for 23% solids, and 3.43 s 1 for 25% solids. The reason for the missing data is that the helical impeller viscometer has limitations. Owing to possible viscometer error, data were not recorded until the impeller torque was >10% of the full-scale torque. Therefore, no experimental data were recorded at low impeller rotational speeds. The lack of experimental data at low shear rates made comparison of rheologic models at low shear rates and the prediction of yield stress impossible.

More recently, studies have applied the probability of extinction as an endpoint to extrapolate short-term effects on long-term population consequences. Based on population viability analysis (Boyce 1992 Groom and Pascual 1997), population size is projected into the future using demographic rates and models that incorporate stochastic effects (Snell and Serra 2000). In practice, it would be difficult to determine extinction rates experimentally due to the need to conduct experiments over multiple generations. Thus, the probability of extinction is typically modeled using the instantaneous rate of increase (Snell and Serra 2000). 

Suzuki E, Ollis DF (1990), Enhanced antibody production at slowed growth rates experimental demonstration and a simple structured model, Biotechnol. Prog. 6 231-236. 

Mutation Distance (A) AG (meV) Packing Calculated log rate Experimental log rate... 

The determination of the chemical reaction rate is based on measurements of the concentrations, temperature and flow rates. Experimental errors in the measurements of these quantities are inevitable. 

The "Performance" ratings experimentally obtained from the 12 experiments designed by the COED program are given in Table IV,... 

To this point the craze fibril volume fraction Vf and fibril extension ratio X have discussed as if they were true constants of the craze. While this view is approximately correct, one would expect the draw ratio of the polymer fibrils to depend somewhat on the stress at which they are drawn, since the polymer in the fibrils should have a finite strain hardening rate. Experimental evidence for just such stress effects on X, is discussed below. 

Our readsorption model shows that carbon number distributions can be accurately described using Flory kinetics as long as olefin readsorption does not occur (/3r = 0), because primary chain termination rate constants are independent of chain size (Fig. 24). The resulting constant value of the chain termination probability equals the sum of the intrinsic rates of chain termination to olefins and paraffins (j8o + Ph)- As a result, FT synthesis products become much lighter than those formed on Co catalysts at our reaction conditions (Fig. 24, jSr = 1.2), where chain termination probabilities are much lower than jS -I- Ph for most hydrocarbon chains. The product distribution for /3r = 12 corresponds to the intermediate olefin readsorption rates experimentally observed on Co/Ti02 catalysts, where intrapellet transport restrictions limit the rate of removal of larger olefins, enhance their secondary chain initiation reactions, and increase the average chain size of FT synthesis products. 

Control Event Rate Experimental Event Rate RRR= ARR = NNT =... 

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