Steady-state digestion

Reaction of purified Ca " -ATPase with 0.3 mM NBD-Cl in the presence of 1 mM AMP-PNP and 1 mM CaCl2 caused inhibition of ATPase activity with the incorporation of 2= 15 nmol NBD-Cl per mg protein [335]. The inhibition was attributed to the binding of 7-8 nmol NBD-Cl/mg enzyme protein, corresponding to = 1 mol NBD-Cl per mol ATPase. The NBD-labeled enzyme was digested with pepsin and several NBD-labeled peptides were isolated [335]. All peptides contained the Gly-X (Cys) sequence that occurs only in one place in the Ca -ATPase, i.e., at Gly343-Cys344. Therefore NBD-Cl reacts with the same cysteine 344 residue that is also modified by maleimide derivatives [319]. The NBD modified enzyme had only 5-10% of the ATPase activity of the control ATPase, but the steady state concentration of the phosphoenzyme intermediate was only slightly reduced [335]. The Ca ... 

Washout Conditions. Here, the bacterial culture into the digester remains inactive or dead which implies that Ai, A2 = 0 for all t > 0. Then, it can be proved that the steady state reached by the AD system (I) under this condition is given by the influent concentration (i.e., S =... 

A range of chemical parameters which have been recorded during steady-state digestion of swine manure during pilot plant studies at the University of Manitoba are recorded in Table 1. 

A steady state for this system is reached when the variations in Cs and Cx have ceased, i.e., when their derivatives with respect to time t are equal to zero in equations (4.23) and (4.24). If we set dCs/dt = dCx/dt = 0 in (4.23) and (4.24), we obtain two coupled steady-state equations for the anaerobic digester, namely... 

Our last task in this subsection is to plot the steady-state substrate and organism concentrations Cs3S and Cxss in terms of the volume V of the digester. 

Having studied the steady-state behavior of the digester, we now turn to its unsteady state or dynamic behavior. 

There has been considerably less work on steady-state carryover in hens. However, in one detailed study it was shown that the absorption of PCDD/Fs from a contaminated soil was quite high, ranging from 70-80% for the tetrachlorinated congeners to 10% for the octachlorinated ones.68 The authors compared their results to feeding studies with rodents and came to the conclusion that absorption from soil was as effective as absorption from easily digestible carriers such as corn oil. 

In the application of electrode potential measurements to anaerobic digestion, the University of Michigan has pioneered (2, 6, 10). Physical chemists have stated that the system theoretically cannot generate sufii-cient electroactivity to make such measurements statistically precise further that thermodynamic reversibility, system equilibrium, and steady-state conditions in such biological systems are suflSciently inexact to permit potential results of meaningful nature lastly, that sludge contaminants are serious enough to distort materially all results (11). 

In a field digester these steady-state values would also be affected by the fact that most of the volatile acids and cations (NH4 ) would be generated internally with some carbon dioxide being produced by the acid-producing bacteria. Acids other than acetic are also formed, and it is of interest to compare the steady state conditions for other volatile acids with those of acetic. The formulas for converting propionic and butyric acids to microorganisms, methane, and carbon dioxide are given in Equations 32 and 33. 

The validity of the model can be tested by subjecting it to simulation conditions which cause failure in field digesters, seeing if the model also predicts failure, and comparing the response of the operational variables given by the simulation with those observed in the field. Simulations of both organic and hydraulic overloading have therefore been made. In both instances the reactor was initially at steady state see Table I) for an input substrate concentration (acetic acid). So, of 167 mmoles/liter, influent net cation concentration, Zo, of 50 meq/liter, and a residence time of 10 days. The liquid volume, V, was 10 liters, and the gas volume, Vcr, was 2.0 liters. 

Worked example 4. A confluence flow injection system with a very low confluent stream flow rate is designed for the spectrophotometric determination of phosphate in plant digests. The linearity of the analytical calibration graph is good and the recorded absorbance corresponding to a 100.0 mg L 1 P (as phosphate) standard solution is 0.21. Replacing the sample carrier stream by this standard solution (sample infinite volume) yields a steady state situation and the related absorbance is 0.68. The pump is then turned off and an asymptotic increase in absorbance towards 0.95 is observed determine the sensitivity improvement that in principle could be attained simply by increasing the sample volume and the mean sample residence time in the analytical path. 

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