Environmental control instrumentation, sensors

Immobilized whole cells are very suitable as sensors in environmental control instruments. In multi polluted waste water it might be difficult to assess the concentrations of each of the polluting molecular species. This is of less interest. Of far greater interest is the net effect on the environment. This point can be cleared up, at least partly, by testing a small sample of the polluted water on a biosystem such as a preparation of immobilized cells. 

As a result of advances made in sensor development, today more so than in the past, it is possible to rely on environmental control in order to gain economical fermentation results. Until recently fermentation control was limited to that of temperature, pH, and aeration. With the development of numerous sensors and inexpensive computing systems, the engineer can think in terms of sophisticated control systems for fermentation processes. Figure 30.5 shows how a highly instrumented fermentor is designed to secure basic information on almost... 

Comments on changes made that went unrecorded in drawings, prints, and records such as the following are found too often in reports on incidents resulting in serious injury, property damage, business interruption, or environmental contamination The system was rewired a blank was put in the line control instruments were disconnected relief valves of lesser capacity had been installed and sewer line sensors to detect hazardous waste were removed. 

Marine pollution by oil spills or harmful chemicals is still one of the major environmental problems to be faced. Besides the accidental releases of pollutants the main source is assumed from the controlled release by ship traffic and oil production platforms. Since accidents or violations of regulations can never be completely excluded, precautions and instruments are needed to detect and combat maritime pollutions and a crucial element of this framework is airborne surveillance. Like no other system, airborne pollution control is capable a) to detect possible oil spills by radar sensors,... 

Application aspects are dealt with in Chapters 15-25. Here, the possibilities and limitations of sensors if compared with the conventional instrumentation in analytical chemistry and calibration aspects are described first. Specific facettes of certain fields of applications are then presented by specialists from different fields including environmental, biotechnological, medical, or chemical process control. 

Recently the use of humidity sensors has greatly increased in a range of industries such as in the production of electronic devices, precision instruments and foodstuffs. As humidity is a permanent environmental factor, its measurement and/or control are of importance not only for human comfort but also for many industries and technologies. In recent years, major domestic applications of humidity sensors have been eg, automatic humidity control in air conditioners, automatic cooking by microwave ovens, and dew sensing on the cylinder heads of VTRs [1, 2]. 

Modern instruments can be easily adapted to particular requirement in process-control applications. By adopting a particular sampling strategy, sensor array can be operated in the laboratory as well as on-line for process-contfol or environmental-monitoring applications. In the laboratory, the detector can be used with a headspace autosampler. Adsorbent trapping units are also available for on-line measurement with a gas chromatographymass spectrometry(GCMS) instrument. The different sensors are built into a very small sensor chamber and usually can be ordered for a particular application. In other words, the gas detection devices can be easily adapted to particular requirement in process-control applications. 

The instrumentation and control (l C) system components are distributed over a large portion of the spaceship, from the sensors and actuators located near the reactor (fore, in, and aft of the radiation shield) to the electronics located in the enclosure at the rear of the spaceship. To allow definition of the environmental requirements for the l C components the thermal and radiation influences in different regions of the spacecraft must be evaluated including the thermal controls and radiation shielding affecting each zone. 

---