OVERSEER model

One example of a discontinuity is a drop in reaction rate due to depletion of reactants as the reaction nears completion. In this case, the step-wise method can still be used, but will tend to oversize. This is because heat losses in the full-scale reactor will cause the reaction to reach completion at a lower temperature/ pressure than was measured in an adiabatic small-scale test, corrected for thermal inertia (see Annex 2). It is not recommended to attempt to take account of heat losses from the full-scale reactor in sizing the relief system (e.g. by modelling them within a computer simulation). This is because a slight overestimation of the rate of heat loss could cause a large underestimation of the relief size required. 

The HEM method will tend, if anything, to underestimate the relief flow capacity and so to oversize relief systems. This is provided the upstream conditions have been correctly specified (see 9.3.3). Another possible exception to the HEM tending to underestimate flow is when there is a large upwards static head change (equivalent to greater than about 10% of the pressure in the reactor), in which case a slip flow model could be more conservative. 

De Scheerder I, Szilard M, Huang Y et al, Evaluation of the effect of oversizing on vascular injury, thrombogenicity and neointimal hyperplasia using the Magic Wallstent in a porcine coronary model [abstr], JACC 2000 35(2) 70A. 

Many pumps installed in industrial facilities are oversized for their actual loads. If possible, reduce the pump size during replacement to increase operating efficiency and reduce maintenance costs. If purchased from a wide variety of vendors, the highest efficiency pumps in each size and class are not necessarily more expensive than lower efficiency models. 

It turns out that the 100-m reactor is grossly oversized. The boldface values in Table 6.2 show a valley in the V — T plane where the annualized unit cost rounds to 2.30 kg . Marketing is somewhat relieved. A more detailed search shows what appears to be a minimum aty = 12m andr = 379 K with an associated cost of 2.3001 kg . Within the boldface area, the maximum cost difference is about 0,005 kg . At a production rate of 50,000,000 kg y, the annual cost difference would be 250,000. However, do not take this number too seriously. An economic prediction accurate to 0,005 kg is unrealistic for anything but an operating plant. There is model error, and there are other factors to consider before a design choice is made. 

The Model UA-5 Is a sensitive, reliable, easy to use absorbance/fluores-cence monitor with built-in calibration standards and recorder. Automatic scale expansion keeps oversized peaks on scale. A selection of thirteen wavelengths (one or two at a time), sixteen different flow cells, and an optional fluorescence optical unit provide Impressive versatility. Absorbance peaks can be automatically deposited into separate test tubes when the Model UA-5 is used with an ISCO fraction coflector, making it possible to recover peaks with the least dilution possible. 

First, a solid model of the object has to be made. This would originally have been done in solid clay or with a pre-existing form. Nowadays it would generally be made of plastercine or Acrylic. These models are always oversized as the finished article shrinks both in the mould and in the kiln. Earthenware, bone china and porcelain may shrink by as much as 15 to 20 percent Parian is considerably more prone to shrinkage and may lose as much as 25 per cent. 

Wheeler, D.M., Ledgard, S.F., de Klein, C.A.M., 2007. Using the OVERSEER nutrient budget model to estimate on-farm greenhouse gas emissions. Austrahan Journal of Experimental Agriculture 48 (2), 99—103. 

Perre and Turner (1997,1999a) have desaibed a numerical model of microwave drying of softwood with an oversized waveguide. In this work, internal overpressure reaching two to three times the atmospheric pressure has been reported both in experimental and numerical results. 

Perre P. and Turner I.W., A complete coupled model of the combined microwave and convective drying of softwood in an oversized wavegnide. Proceedings of IDS 1996, Vol. A, 1996, pp. 183-194. 

Calculations have confirmed that the standard C-e model of turbulence gives oversized values, such as the values of kinetic turbulence energy, C. Much better results are obtained using the KECHEN and KERNG models (Figure 2.14), especially designed for detached flows with circulation zones. 

Fig. 3.12 Cumulative pore volume oversize and pore frequency distributions by volume by nitrogen gas porosimetry using a cylindrical pore model.

The interface of the leachate and clay liner material was modelled using a simple tank system. A perspex box (350 x 350 x 50 mm) was filled with a layer (depth 20 mm) of pre-saturated clay. The clay was collected at the same time and from the same location as the samples used in the column experiments and was pre-saturated with tap water, to minimize wetting and capillary effects. The tank was filled with leachate to a depth of 40 mm and the head space flushed with nitrogen. An oversized lid and water filled trench... 

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