Constant-rate mode

Constant-rate mode The temperature was decreased from 425 to 273 K at a constant rate of 1 K/min, and then increased from 273 to 425 K at the same rate. This is a simple constant-rate mode and we refer to this temperature change as the reference mode. In addition to the above thermal treatment, we included an intermittent stop at T for fa h during cooling from 425 to 273 K. This temperature protocol is denoted as C(7 a, fa). According to this notation, the reference mode corresponds to the protocol C(Ta, 0) for any value of T. ... 

We can see that the process monotonously slows down during electrolysis and its rate asymptotically approaches zero. Therefore, the constant rate mode carmot be reached on planar electrode under given conditions. The obtained equation may be called the chronoamperogram equation of a diffusion process. Compare it to the relationship that describes the maximal rate of an electrode process under stationary linear diffusion ... 

The classic way that we perform force versus deformation measurements is to deform a sample at a constant rate, while we record the force induced within it. We normally carry out such tests in one of three configurations tensile, compressive, or flexural, which are illustrated in Fig. 8.1. We can also test samples in torsion or in a combination of two or more loading configurations. For the sake of simplicity, most tests are uni-axial in nature, but we can employ bi-axial or multi-axial modes when needed,... 

Constant conduction heat pipes, 13 227 Constant failure rate, 13 167 Constant-field scaling, of FETs, 22 253, 254 Constant-modulus alloys, 17 101 Constant of proportionality, 14 237 Constant pressure heat capacity, 24 656 Constant rate drying, 9 103-105 Constant rate period, 9 97 23 66-67 Constant retard ratio (CRR) mode, 24 103 Constant slope condition, 24 136-137 Constant stress test, 13 472 19 583 Constant-voltage scaling, of FETs, 22 253 Constant volume heat capacity, 24 656 Constant volume sampling system (CVS), 10 33... 

The titration procedures described in the literature can be classified as continuous or incremental, depending on the mode of titrant addition. In the first case the titrant is continuously introduced in the reaction vessel at a programmed (not necessarily constant) rate during a run. The application of this method requires apparatus with quick response to temperature changes and can be used only to study fast reactions. Slow reactions (i.e., those with a reaction time longer than the equilibrium time of the reaction vessel) may be accurately studied by the... 

A standard HPLC pump (Spectra Physics 8700) is used in constant-pressure mode and pulse-free flow rates from 1 to 5 yL/min are obtained without any modifications of the pump. 

An exothermal reaction is to be performed in the semi-batch mode at 80 °C in a 16 m3 water cooled stainless steel reactor with heat transfer coefficient U = 300 Wm"2 K . The reaction is known to be a bimolecular reaction of second order and follows the scheme A + B —> P. The industrial process intends to initially charge 15 000 kg of A into the reactor, which is heated to 80 °C. Then 3000 kg of B are fed at constant rate during 2 hours. This represents a stoichiometric excess of 10%.The reaction was performed under these conditions in a reaction calorimeter. The maximum heat release rate of 30Wkg 1 was reached after 45 minutes, then the measured power depleted to reach asymptotically zero after 8 hours. The reaction is exothermal with an energy of 250 kj kg-1 of final reaction mass. The specific heat capacity is 1.7kJ kg 1 K 1. After 1.8 hours the conversion is 62% and 65% at end of the feed time. The thermal stability of the final reaction mass imposes a maximum allowed temperature of 125 °C The boiling point of the reaction mass (MTT) is 180 °C, its freezing point is 50 °C. 

A condensation reaction is to be performed in a stirred tank reactor in the semibatch mode. The solvent is acetone, the industrial charge (final reaction mass) is 2500 kg, and the reaction temperature is 40 °C. The second reactant is added in a stoichiometric amount at a constant rate over two hours. Under these conditions, the maximum accumulation is 30%. The reaction does not produce any gas and its heat release rate is 20 Wkg h The reactor is equipped with a condenser with a cooling power of 250kW and the vapor tube has a diameter of 250mm. The reactor can be considered open. 

This mode of operation demands constant rate of distillate throughout. This means that, for constant reflux ratio operation, the vapour load to the condenser is also constant. Boston et al. (1981) and Holland and Liapis (1983) considered this type of operation. 

Two modes of operation are possible in applying a load to an agglomerate. With an automated tester the more common procedure is to move the platens at a constant rate this is a constant deformation rate tester (CDRT). A second mode is possible in which the compressive force on the agglomerate is increased at a constant rate this is a constant loading rate tester (CLRT). Cahn and Karp inski [29] provide an interesting comparison of these two modes of operation and conclude that the CLRT should be used when accuracy and precision are emphasized whereas the CDRT will suffice for routine testing. 

Smedarchina Z, Femandez-Ramos A, Siebrand W (2001) DOIT a program to calculate thermal rate constants and mode-specific tunneling splittings directly from quantum-chemical calculations, J Comp Chem 22 787-801... 

Set the oven temperature to ramp 140° to 350° at a rate of 10°/min (total run time of 21.0 min). Set the track mode to on (injector temperature follows the oven temperature conditions). Set the injection mode to on-column injection. Set the FID at 375°. Set the hydrogen carrier gas constant flow mode to on with a pressure of 5.5 psi (140°). 

The latter equation can be used to calculate v or L as a function of time t, once the filtration mode is specified, e.g., constant-pressure filtration, with p constant constant-rate filtration, with constant or centrifugal-pump filtration, with q as a function of p. 

For the injection, a modified Ruska pump was used. The body of the pump was manufactured by the Ruska Instrument Company of Houston, Texas. It is equipped with an electronically controlled drive train developed at New Mexico State University. It can be controlled to run in either a constant rate, a constant pressure or a constant differential pressure mode. 

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