Contamination sensor parameters

A process variable is a parameter of the current status of a process under operation, and, therefore, the measurement of process variables is a key to understanding what is happening in a bioreactor and to being able to control the process. Most of the sensors used for the measurements of process variables are inserted into the culture broth of a bioreactor. These must have qualities that will allow them to be repeatedly sterihzed (autoclavable) in order to prevent microbial contamination in bioreactors. Naturally, all the sensors must be calibrated before sterihzation. 

In contrast to engine oil, transmission (or gearbox) oil usually represents a lifetime filling unless unexpected contamination due to failures occurs, which, depending on the kind of contamination, may be detected potentially by all the physical parameters considered. For the detection of metallic wear particles in transmission oil, both ferromagnetic as well as non-ferromagnetic, the utilization of magnetic sensor principles would be near at hand [16, 17]. 

The Radiometer ICA 113 Is an Improved version of their former ICA 1. It Is a modular Instrument for the automatic anaerobic measurement of calcium and pH in serum and plasma. Because of the close relationship between these two parameters, their simultaneous measurement Is essential as a normal Ionized calcium value may be accompanied by an anomalous pH and vice versa —this may lead to erroneous diagnoses. The sensor of the ICA 113 consists of an F2111 Ca Selec-trode whose PVC membrane Is protected from contamination by proteins by a... 

U.K.), and the Six-Cense system (Dascore, Inc. South Carolina). Details of some of these sensors are available in the EPA report on EWS [9], The sensor systems can give a first-step indication of toxicity assessment, as any change in the chemical/physical parameters of the sample will be recorded and taken as possible contamination, where samples will be removed and analyzed for toxicity confirmation. Further details on EWS are also covered by Grayman et al. [6] and Hasan et al. 

Conductivity sensors A very significant parameter that gives a measure of the concentration of ions in industrial process streams is conductivity. The continuous measurement of conductivity in process streams is a common practice in the monitoring of boiler feed water, brackish water, demineralization, industrial process media, municipal and industrial wastewater, surface waters, and water treatment. Specific areas of application for conductivity sensors include control of drinking water and ultrapure water quality, determination of nonspecific contaminants, monitoring of salt load in wastewater... 

It should be noted that other metal oxides used in humidity sensors did not show parameters comparable with parameters of Al Oj-based devices (Chen and Lu 2005). It was also found that metal oxide ceramics are highly sensitive to contaminants such as dust and smoke (Clayton et al. 1985 Nakajima et al. 1999). This means that they require maintenance, e.g., by heating them from time to... 

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