Dilution rate definition

One can employ the definition of the dilution rate to ascertain the volumetric flow rate at which washout is observed ... 

Here we have also recognized that if the contents of the bioreactor are perfectly mixed, JCj = j cstbr- Algebraic manipulation of equation (13.2.58) combined with use of the definition of the dilution rate yields... 

Despite the fact that productivity of chemostat operation is similar to turbidostat operation the turbidostat is preferred especially at locations with more day-to-day variation in irradiance. Under chemostat operation biomass concentration will slowly decrease on consecutive days with cloud cover. If followed by a clear-sky day, the culture is vulnerable to photoinhibition because of its low biomass concentration. Turbidostat operation allows for a direct control of biomass concentration. Washout of a microalgae culture in a turbidostat is by definition not possible. In a chemostat this could occur in situations the dilution rate is not adjusted in time. Turbidostat operation is thus more robust and allows for rehable automation of outdoor microalgae production (Bosma et al, 2014). 

Since (l+r-rC)dilution rates greater than the maximum growth rate. Utilizing the definition ofy from equation (9), the following expressions for the growth limiting substrate, S, system effluent biomass concentration, X, and biomass concentration in the exit stream from the bioreactor, X, are obtained ... 

Tbe mass-transfer coefficients k c and /cf by definition are equal to tbe ratios of tbe molal mass flux Na to tbe concentration driving forces p — Pi) and (Ci — c) respectively. An alternative expression for tbe rate of transfer in dilute systems is given by... 

Discussion. The turbidity of a dilute barium sulphate suspension is difficult to reproduce it is therefore essential to adhere rigidly to the experimental procedure detailed below. The velocity of the precipitation, as well as the concentration of the reactants, must be controlled by adding (after all the other components are present) pure solid barium chloride of definite grain size. The rate of solution of the barium chloride controls the velocity of the reaction. Sodium chloride and hydrochloric acid are added before the precipitation in order to inhibit the growth of microcrystals of barium sulphate the optimum pH is maintained and minimises the effect of variable amounts of other electrolytes present in the sample upon the size of the suspended barium sulphate particles. A glycerol-ethanol solution helps to stabilise the turbidity. The reaction vessel is shaken gently in order to obtain a uniform particle size each vessel should be shaken at the same rate and the same number of times. The unknown must be treated exactly like the standard solution. The interval between the time of precipitation and measurement must be kept constant. 

The formation of activated species during mechanoehemieal degradation is, in general, not sufficiently documented both experimentally and with respect to the proposed mechanisms to give a definite proof of their existence. In the dilute state, the rate of energy transfer is high and it is reasonable to assume that any activated species, if present, will be thermalized well before the occurrence of a chemical reaction. 

In the semi-dilute regime, the rate of shear degradation was found to decrease with the polymer concentration [132, 170]. By extrapolation to the dilute regime, it is frequently argued that chain scission should be nonexistent in the absence of entanglements under laminar conditions. No definite proof for this statement has been reported yet and the problem of isolated polymer chain degradation in simple shear flow remains open to further investigation. 

Many site-specific characteristics have an impact on vitrification technologies. One critical aspect of any thermal technology is the water content of the waste. Water dilutes feed material, requires energy to drive off, and physically limits the feed rate of waste. Feed preparation is another variable, which differs with the technology and with site-specific characteristics. Many estimates do not take into account site preparation and waste disposal costs. Only complete treatment life-cycle assessments can provide reliable comparison data, and such studies are, by definition, highly site and waste specific (D18248T, p. 55). 

The rate constant of dilution is calculated from the definition of concentration, C as mass flux per unit time, m, divided by volume flux of water, Q ... 

Figure 8.14 shows the result of combining the correlations of /30 (Fig. 8.13) and JeR (Fig. 5.18). The product (30Jcr is remarkably independent of concentration and molecular weight from infinite dilution all the way to the undiluted melt state and shows no substantial variation from one polymer to another. For the particular definition of critical reduced shear rate y0 used here, the experimental result for narrow distribution linear chains can be expressed as...

Thus, firstly, the choice of the pure solvent as the reference state for the definition of activities of solutes in fact impairs a fair comparison of the activity of dilute solutes such as general adds to the activity of the solvent itself. Secondly, the observed first-order rate constants k or k0 for the reaction of a solute with the solvent water are usually converted to second-order rate constants by division through the concentration of water, h2o = oA iho, for a comparison with the second-order rate coefficients HA. Again, it is questionable whether the formal h2o coefficients so calculated may be compared with truly bimolecular rate constants kUA for the reactions with dilute general acids HA. It is then no surprise that the values for the rate coefficients determined for the catalytic activity of solvent-derived acids scatter rather widely, often by one or two orders of magnitude, from the regression lines of general adds.74... 

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