Centrifugal absorber

The diastase activity was traditionally determined according to the Schade method in the earlier years (Schade et al., 1958). One unit of diastase activity (or more specifically, a-amylase), DN, is defined as that amoimt of enz)nne that converts 0.01 g of starch to the prescribed endpoint in 1 h at 37 °C under the experimental conditions. In this assay, a standard solution of starch, which reacts with iodine to produce a color solution, is used as a substrate for honey enzymes under the standard conditions (Rendleman, 2003). A recently developed procedure uses an insoluble, dyed starch substrate (Persano Oddo and Pulcini, 1999). As this substrate is hydrolyzed by ot-amylase, soluble dyed starch fragments are released into solution. After reaction termination and insoluble substrate removal by centrifugation, absorbance of the supernatant solution (at 620 nm) is measured. The absorbance is proportional to the diastase activity. This procedure has been widely adopted in the honey industry due to the convenience of a commercially available substrate and the simple assay format. 

For activity assays, proteinase solutions were made fresh daily (10 mg freeze-dried solids in 1 ml pH 10.0 phosphate buffer, 0.1 M). Two ml of the proteinase, 0.5 ml of substrate (azocasein or other proteins in pH 10 buffer), 0.3 ml of 0.1% EDTA, and deionized water were made up to a volume of 3.5 ml. Reaction tubes were incubated in a 40°C water bath for 1 hr, then the reaction was stopped by addition of 1 ml 5% TCA. After removal of the precipitated proteins by centrifugation, absorbance was read at 366 nm (for azocasein) or by the Lowry method (15) for other... 

Separators centrifugal absorbers, rotating packing beds... 

It should be noted that the RZB is very similar to the centrifugal absorber unit described by Chambers and Wall in 1954, as shown in Figure 12.32 in Coulson and Richardson (1978). The reader who has studied Chapter 1 will also see an internal geometry similarity with the Moss still in Figure 1.9. 

Gauze Roll % Moisture Regain DS Dunk-N-Drain Absorbency Factor, g/g Centrifuge Absorbency Factor, g/g... 

About 10 mg of DPH crystals were immersed in 3 ml of a 10 mM (Q-P(TDAE)ii solution, and this preparation was sonicated for 1 h (Branson 200, 19 W) in order to saturate the hydrophobic core ofthe polycation with the fluorescence marker. After a 20-min centrifugation, absorbance of the supernatant was measured at 350 nm in order to check the presence of DPH. 

The urea solution leaving the stripper bottom contains about 12 wt% of NH and is further purified in the 1.8 MPa (18 bar) and 0.2 MPa (2 bar) recovery sections of the plant. The resultant NH and CO2 separated in the decomposers is absorbed and returned to the synthesis section by the high pressure centrifugal carbamate pump. 

Fig. 3. Typical nitric acid oxidation process. A, reactor B, optional cleanup reactor C, bleacher D, NO absorber E, concentrating stUl F, crude crystallizer G, centrifuge or filter H, refined crystallizer I, centrifuge or filter , dryer K, purge evaporator L, purge crystallizer M, centrifuge or filter N,...

Fig. 9. Schematic of KNO2 from NH2 and KCl A, KCl—HNO2 reactor B, NOCl oxidizer C, acid eliminator D, gas stripper E, water stripper F, H2O—HNO2 fractionator G, evaporator—crystallizer H, centrifuge I, NO—NO2 absorber , NH2 burner K, CI2 fractionator and L, NO2 fractionator.

The gaseous ammonia is passed through electrostatic precipitators for particulate removal and mixed with the cooled gas stream. The combined stream flows to the ammonia absorber where the ammonia is recovered by reaction with a dilute solution of sulfuric acid to form ammonium sulfate. Ammonium sulfate precipitates as small crystals after the solution becomes saturated and is withdrawn as a slurry. The slurry is further processed in centrifuge faciHties for recovery. Crystal size can be increased by employing one of two processes (99), either low differential controUed crystallization or mechanical size enlargement by continuous compacting and granulation. 

The per pass ethylene conversion in the primary reactors is maintained at 20—30% in order to ensure catalyst selectivities of 70—80%. Vapor-phase oxidation inhibitors such as ethylene dichloride or vinyl chloride or other halogenated compounds are added to the inlet of the reactors in ppm concentrations to retard carbon dioxide formation (107,120,121). The process stream exiting the reactor may contain 1—3 mol % ethylene oxide. This hot effluent gas is then cooled ia a shell-and-tube heat exchanger to around 35—40°C by usiag the cold recycle reactor feed stream gas from the primary absorber. The cooled cmde product gas is then compressed ia a centrifugal blower before entering the primary absorber. 

Centrifugal pumps are made up of several components and are expected to cope in a multitude of environments, some quite hostile, fin understanding of houi they luorh, uihy they tuorh, luhy and houi they go turong and luhat to da about It can only come from a mix of theory and experience, hut the theory needs to be presented in a form which Is absorbable and Interesting if it is to he retained... 

The pressure at any point in the suction line must never be reduced to the vapor pressure of the liquid (see Equation 3-6). Both the suction head and the vapor pressure must be expressed in feet of the liquid, and must both be expressed as gauge pressure or absolute pressure. Centrifugal pumps cannot pump any quantity of vapor, except possibly some vapor entrained or absorbed in the liquid, but do not count cm it. The liquid or its gases must not vaporize in the eye/entrance of the impeller. (This is the lowest pressure location in the impeller.)... 

Centrifugal pumps, as do most other mechanical equipment, generate dynamic forces that must be absorbed by their foundation. The foundation should have a mass that is at least five times that of the installed pump and driver. In addition, the pump assembly must be properly affixed... 

Whole cell OPH activity was measured by following the increase in absorbancy of p-nitrophenol from the hydrolysis of substrate (0.1 mM Paraoxon) at 400 nm (sm = 17,000 M cm ). Samples of culture (1 ml) were centrifuged at 10,000 g and 4 C for 5 min. The cells were washed, resuspended with distilled water, and 100 pi was added to an assay mixture containing 400 pi 250 mM CHES [2-(N-cyclohexylamino)ethane-sulfonic acid] buffer, pH 9.0, 100 pi 1 mM Paraoxon, and 400 pi distilled water. One unit of OPH activity was defined as pmoles Paraoxon hydrolyzed per min. Each value and error bar represents the mean of two independent experiments and its standard deviation. 

In the Phadebas TM amylase test (72) (Pharmacia Labs) the substrate was a water insoluble cross-TTnked blue starch in tablet form which also contains some inert ingredients, sodium and potassium phosphate buffer salts and sodium chloride. This polymer was hydrolyzed by amylase into water soluble blue starch fragments. After centrifugation the absorbance of the blue supernatant was proportional to the activity of amylase present in the test samples. The day to day variation on a quality control serum had a coefficient of variation of 2.7% based on 30 days of data in our laboratory. The method is simple, reproducible and uses microquantities of serum. 

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