Parameters to Monitor Degradation

The purpose of the trial also affects the choice of degradation agents and the parameters used to monitor degradation. For comparison and quality control purposes, single agents are most frequently used. For prediction purposes multiple agents are more likely to be representative of service, but at the same time they make extrapolation rules more complicated. The parameters measured in trials to predict lifetime must be those critical to service, but in many instances of comparison or quality checks the choice of parameter can be heavily influenced by experimental convenience. 

The parameters used to monitor degradation are not the ones critical to service performance. 

The flow rate degradation parameter to monitor over time is defined as ... 

The longer a component is retained by the column, the greater is the capacity factor. To monitor the performance of a particular column, it is good practice to periodically measure the capacity factor of a standard, the number of plates (Equation 23-28), and peak asymmetry (Figure 23-13). Changes in these parameters indicate degradation of the column. 

One of the objectives of this experiment was to monitor in-situ redox and pH conditions in the EC. Knowledge of these two parameters is important in any interpretation of degradation reactions involving chloro-organic compounds in which electrons and protons are involved, as in reductive dechlorination, for example. 

The optimal RIA parameters of the talc-resin-TCA test also apply to iodohormones used in bioassays and radioreceptor assays (RRA). The talc and TCA testing has been used to monitor the degradation of I-la-beled hormone used with prolactin, insulin, and growth hormone receptors. Strict adherence to the limits of >90% talc adsorption, <25% resin binding, and >90% TCA precipitation provides a rigorous quality control for the presence of bioactive and receptor-affinitive monomeric iodohormone. 

In this paper, we will discuss data collected as a part of two recent field studies, one in Georgia and the other in Florida. The objective of both studies was to monitor the environmental dynamics of pesticides in the crop root zone and to use these data to evaluate the predictive capability of several simulation models. Specific attention will be focused on the data characterizing the spatial variability of pesticide sorption and degradation parameters measured at these two field sites. 

During the last decade numerous applications were developed employing fluorescent proteins. This includes passive applications such as the use of fluorescent proteins as fluorescence tags in fusion proteins to monitor the appearance, degradation, location or translocation of appropriate partner proteins, as well as more active applications measuring biochemical parameters such as metabolite concentrations, enzyme activity, or protein-protein interactions by their effects on the fluorescence properties of appropriately designed derivatives of fluorescent proteins (biochemical sensors/indicators) [76]. 

Two methods are used to monitor concentration and to restrict excessive use of polymer additives in contact with food quantity in the materials and specific migration hmit. If a compound degrades in a food simulant, the quantity in the material should be used. From this follows that for stability of additives it is important to establish which parameter has to be controlled. Low molecnlar weight plasticizers, such as di-(2-ethylhexyl) adipate and di-(2-ethylhexyl) phthalate, are known to migrate into food on contact. Their studies in various food simulants show that both materials are fairly stable and thus the quantity in the material is postulated to be used in screening of packaging materials. ... 

Normally, the active power of the AC-motor measured from the switchgear room and the baseline measurement allow the monitoring of all functional relevant parameters to verify readiness for function. Degradation or deviations in the function of the valve and the actuator with respect to upcoming failures can be detected in advance. If there are any indications of deviations from certain tolerances further parameters are measured in-situ like torque, stem thrust and the displacement of the worm gear. 

---