Sink capacity

Tuber structure in cross section from exterior to interior can be separated into the epidermis, cortex, outer medulla, inner medulla, and pith (Mazza, 1985). Relatively little is known about the temporal sequence of cell division and differentiation leading up to bulking. Sink capacity is a function of the combined vacuolar volume of the tubers, the location of fructan synthesis and storage within the cells (Darwen and John, 1989 Keller et al., 1988 Pollock, 1986). Vacuolar volume is a function of cell size and number. The size of individual cells within the tuber varies with tissue type cortex (286 cells per 10 mm2), extension zone (145 cells per 10 mm2), storage tissue (85 cells per 10 mm2), and pith (149 cells per 10 mm2) (Schubert and Feuerle, 1997). The extent that cell number and size increases after the initial formation of the tuber has not been adequately documented. 

The accumulation of carbon in the organic layer after fire points at a basic problem of the simplified flux scheme of Schulze and Heimann (1998), namely, that intermediate pools exist at each level with different mean residence time, and depending on the level of spatial integration these pools may or may not average out. The problem is illustrated in Figure 7, where an inventory-process type approach (in contrast to eddy covariance flux measurements) was chosen to calculate the carbon sink capacity of European forest ecosystems. If NPP was plotted against C-mineralization, then NPP minus C-mineral-ization would represent NEP at the plot scale (Schulze et al.,... 

The combined information will give new insight into. soil carbon turnover and will help to understand and to quantify ecosystem-specific retention mechanisms for carbon. Additionally, this information may identify the carbon sink capacities of soils. 

Simplification of process and safety systems by taking advantage of particular inherent small reactor characteristics. For example, natural circulation in some BWR concepts (not practical in large-size units because of pressure vessel size limitations) taking advantage of the high heat sink capacity/capability of small gas-cooled reactor cores. 

The specific design features, methods or mechanisms for achieving the necessary level of nuclear safety are, however, in some SMPR concepts different from those used in larger-size units of the same type, because advantage has been taken of the inherent possibilities offered by the smaller size of the reactors. Examples are the HTR concepts which utilize the large inherent heat sink capacity. 

During the first thousand seconds, residual power is removed by the SG and by the RRP system. To prevent steam release to the atmosphere, the steam is condensed in a dedicated pool. With 4 RRP loops and 5 SG tubes ruptured, the mass of released steam is about 40 to 50 tons, depending on the RRP heat sink capacity with 8 RRP loops the mass of released steam is 20 tons. After six thousand seconds, the RRP system is sufficient to adequately cool the reactor and the steam release from the SG is stopped. 

Heat is then added to the liquid to convert it to a gas and raise it to a temperature sufficient to avoid the liquid region during the expansion of the cycle between points 3 and 4, This value also can be represented by an enthalpy change and it represents the potential heat-sink capacity of the system. Again, it must be emphasized that this initial analysis represents 100 per cent component efficiency. Under actual conditions the values will be somewhat less. 

For point A, which represents 10 horsepower for 10 minutes, 140 lbs, of nitrogen is required, and is stored in 2.8 cu, ft. This quantity will provide a heat-sink for 27,600 BTU. This same power level and duration would require 40 lbs, of hydrogen, a storage volume of 30,8 cu, ft, and provide a heat-sink capacity of 97,000 BTU. 

For point B, 9,720 lbs, of nitrogen is required and occupies 194 cu, ft. with a heat-sink capacity of 1,910,000 BTU, Here 1,400 lbs, of hydrogen would be required, with a comparable storage volume and heat-sink capacity. 

Thus, this paper shows that a cryogenic system is feasible only where a large heat-sink capacity is required. 

---