Control aerator with

Sodium Adsorption Ratio. Because of the swelling effects of Na+, the relative amount of sodium (sodicity) in the water quality especially in the irrigation water quality is an important measurement in soil science. Decreased permeability can interfer with the drainage required for normal salinity control and with the normal water supply and aeration required for plant growth. The relative sodium status of irrigation waters and soil solutions is often expressed by the sodium adsorption ratio (SAR)... 

DO profile during control. The sensitivity of the DO concentration to load changes is largest in subreactor 3, so DO(3) has been chosen for control. With a discrete time controller supplied with a feed-forward signal from the influent flow rate the total air supply to the four subreactors was controlled to keep DO(3) as constant as possible, fig 9. Even if the regulator is not optimally tuned, the improvement of the aerator performance as seen by the DO profile is significant. 

Figure 9. The aerator with DO control of DO(3), showing the total air-flow rate and the DO concentrations...

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... 

As background, the AOCS active oxygen method (AOM) test uses 100 meq peroxide/1000 g sample as the end point for predicting hours of stability of a fat sample heated at 97.8 0.2°C, under controlled aeration. But, in food-grade applications, major buyers of frying oils typically specify 1 or 2 as the maximum allowable PV at receipt. In soy oil, 1.0-5.0 PV is considered low oxidation, 5.0-10.0 PV moderate oxidation, and lO-f high oxidation. The flavor of oil with a PV above 20 usually is so unacceptable that the product is of little interest. 

Figure 19.1 shows an airlift bioreactor contains external loop which is made of Pyrex glass. The bioreactor was fed with sweet cheese sterilized and deprotenized whey. The cell suspension was aseptically transferred to the bioreactor. Airlift bioreactor was operated at working volume of 7 liters that included 10% pre-culture. The regulation system allows for temperature control at 30 1°C foam-level and pH controlled by addition of antifoam and ammonia, respectively. The set-point fixed at pH 5.0 0.1. The system was aerated with filtered air at a different flow rate of 0.1, 0.4, and 0.8 vvm that was controlled using an aeration pump controller Each run was achieved in duplicates the average values of lactose, ethanol, and biomass concentrations were calculated and monitored with respect to time. 

Until recently, fermentation control was limited to that of temperature, pH, and aeration. With the development of numerous sensors and inexpensive personal and minicomputers, the engineer can think in terms of sophisticated control systems for fermentation processes. 

The relatively concentrated hydrochloric acid is employed so that with ordinary use of the apparatus, spent liquor does not accumulate very rapidly the concentrated acid also ensures a brisk and delicately controlled flow of gas. When the generator is replenished with acid, marble or both, the de-aeration procedure detailed above is repeated until a sufficiently air-free gas supply is obtained. 

An industrial fermentor of capacity up to several hundred kiloliters equipped with aeration and stirring devices, as well as other automatic control systems, is used. The cultures must be sterilized and aseptic air must be used owing to the high sensitivity to bacterial contamination of L-glutamic acid fermentation. 

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