Usage rate

It is also important to study the interactions of papermaking additives (4) in the paper machine water system some additives act synergisticaHy, so that the performance of each is enhanced by the presence of the other. However, some additives have a negative impact on the performance of other additives, or on other desirable paper properties. Thus, optimization of the addition points and usage rates of the entire additive system is necessary in order to maximize performance of the chemical additives and the paper sheet properties, and to minimize cost and negative interactions both on the paper machine and in the white-water system. This is especially tme as unanticipated additives enter the wet end of the paper machine from recycled furnishes, including coated broke (5). 

Active dry yeasts of improved quality have been available for many years, and more recently instant active dry yeast has been introduced (15,20). This instant yeast exhibits more activity than regular active dry yeast due to improved drying techniques, and can replace compressed yeast at a rate of 33 —40%. Dried yeasts, which are stable for long periods of time at room temperature, are of interest to bakers because of the high distribution cost of fresh compressed yeast. This is especially tme for those away from distribution centers and for smaller bakers whose usage rate of yeast is low. 

The energy efficiency of transit per passenger distance traveled depends both on its usage rate (person travel per vehicle travel) and its fuel efficiency (fuel consumption per vehicle travel). The transit vehicles with the greatest potential for energy efficiency gains... 

Summary of Water Usage Rates for the Coil Coating Industry by Subcategory... 

Porcelain enameling plants are located primarily in the states of Wisconsin, Illinois, Indiana, Michigan, Ohio, Pennsylvania, Kentucky, and Tennessee. Of the facilities, 76% discharge to publicly owned treatment works (POT Ws), 22% to streams or rivers, and 2% to both. Approximately 10% of the plants recycle, with an average recycle of 9.6 m3/h, which represents 46% of the average process water usage rate of 20.8 m3/h. The total porcelain enamel applied each year by all plants is estimated at 150 x 106 m2. 

Another important factor is the food/nutrient ratio. Many of the necessary nutrients may already be present in the aquifer, such as K, Mg, Ca, S, Na, Mn, Fe, and trace elements however, N and P may be deficient and need to be added. The optimum ratio of BOD N P is 100 5 1. It is not a good practice to inject a large quantity of nutrients in the aquifer at one go. They should be fed at the required usage rate throughout the cleanup process. Both the organic contaminants and the nutrients should be completely exhausted by the end of the in situ remediation of an aquifer. 

The compounds MTBE and disopropyl ether (DIPE) are sometimes found as additives in gasoline. Both have very high carbon usage rates thus, the costs of removing these compounds are... 

Petroleum hydrocarbons (benzene, toluene, ethylbenzene, and xylenes—collectively BTEX), particularly benzene, are believed to pose significant health concerns, especially as they are contained in over 99% of all gasoline. However, additives such as MTBE and DIPE, which have high carbon usage rates, are not found in all gasolines and hence pose less significant health concerns. Thus, GAC is generally applicable for the removal of BTEX. 

A 14-day supply is the usual number used for design. Calculating the maximum daily usage rate by 14 yields a conventional estimate of liquid fuel storage required. 

Electrolytic hygrometers cannot lie exposed lo high water vapor fcvels for any long period of lime because this results in a high usage rate for the PiOj and high cell currents. 

Calculation of Specific Oxygen Usage Rate Throughout a Test. .. 42... 

In an efficient commercial phytoproduction process, the cells will be in contact with near optimum concentrations of each dissolved gas. However, to insure that this occurs, the designer must know both the ideal concentrations and (for material balance reasons) the production and usage rates. 

Taticek et al. tabulated several values of maximum specific 02 usage rates, which range from 0.2-0.6 mmol g, h 1 [6]. Our experiments with A. annua suspension cell cultures indicate a maximum specific usage rate of 0.2 mmol g, h1. The wide variation in usage rates is suspicious it may be an artifact of the variety of methods of estimation. 

For comparison, several specific usage rates for industrially important bacteria and fungi are given. These range from 3.0 (Aspergillis niger) to 10.8 mmol gd, h 1 (Escherichia colt) [24]. 

It is necessary to estimate the quantity of each gas in the liquid to accurately determine the productivities and usage rates. The species equilibrium concentration, x, in the liquid is estimated by Henry s Law (Eq. 3). Unfortunately, H, the Henry s Law constant, for a gas in contact with a solution depends on the nature and concentrations of dissolved solids, tending to be less than the value for pure water [71]. For this reason, we can only obtain an upper limit for the dissolved gas quantity. However, the solubility depression for our rather dilute culture medium is low. A 0.5 mole/1 concentration of sodium chloride results in an oxygen solubility depression of 15 % [71]. The total concentration of dissolved solids in our medium was less than half of that (0.22 mole/1), so the gas solubility depression was almost certainly less than 10%. A more serious uncertainty occurs because the culture volume includes cell volume by treating the entire 83 ml as liquid volume (V ), we may tend to overestimate the dissolved gas quantity. 

The rate quantity of interest for each gas species is the specific productivity (for 02, the specific usage rate), i. e. the amount of gas produced (or used) per... 

The initial specific 02 usage rate, o02 (in millimoles per hour per gram of dry biomass), is thus estimated as ... 

Cultures started with 10-day-old inoculum produced significantly more C02 than did those started with 21 -day-old inoculum. Again, there was no difference in 02 usage rates. This appears to suggest that much of the 21-day-old inoculum was dead, agreeing with the interpretation of the a vs. c test results (2) above. Partly as a result of this experiment, it was decided to subculture every 10 or 11 days (twice every 3 weeks). 

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