Input flux

If a surface has a specified net thermal input flux, say qIh then, from equation 9.140 ... 

The enormous volume of the oceans results in an average turnover time of more than 2600 years, compared to less than 10 days for atmospheric water. Although the reservoir is much smaller than the oceans, the cryosphere has the longest turnover time due to the small input flux. Average turnover times for all seven reservoirs, calculated from the data in Fig. 6-3, are shown in Table 6-3. 

Assuming an input flux equal to oceanic evaporation, this would give a turnover time of about 750 years. The turnover time analysis is not strictly correct since freshwater resides in a number of interconnected reservoirs however. 

Model simulations of particle volume concentrations in the summer as functions of the particle production flux in the epilimnion of Lake Zurich, adapted from Weilenmann, O Melia and Stumm (1989). Predictions are made for the epilimnion (A) and the hypolimnion (B). Simulations are made for input particle size distributions ranging from 0.3 to 30 pm described by a power law with an exponent of p. For p = 3, the particle size distribution of inputs peaks at the largest size, i.e., 30 pm. For p = 4, an equal mass or volume input of particles is in every logaritmic size interval. Two particle or aggregate densities (pp) are considered, and a colloidal stability factor (a) of 0.1 us used. The broken line in (A) denotes predicted particle concentrations in the epilimnion when particles are removed from the lake only in the river outflow. Shaded areas show input fluxes based on the collections of total suspendet solids in sediment traps and the composition of the collected solids. 

As noted above, it is likely that the calcium input fluxes to the oceans and the outputs fluxes are not always equal. According to Equation (5), this means that the seawater 5 Ca ratio can vary with time. The rapidity with which the seawater 5 Ca can change is dictated by the residence time of calcium in seawater. At present, the residence time is estimated to be about 1 million years (e g., Holland 1978). In the past, the residence time could have been larger or smaller, perhaps by as much as a factor of 5 or even 10, depending on the Ca concentration in seawater (Fig. 12) and the riverine, diagenetic and hydrothermal fluxes of calcium to the oceans. 

The above equation demonstrates that air-water exchange as well as other boundary exchange processes can be interpreted as a combination of an input flux (7ia/w = oVia/wQa/ 7fia/w) and an output flux (0,a/w = A0v,a/wC, surface). It is a matter of personal taste whether one prefers to keep both terms separated or add them to get the familiar form of a net exchange flux. 

In addition to those attributes of real natural water systems mentioned above, there is one other which is often important. These systems are open to their environment. They receive various inputs (fluxes) of matter and energy from their surroundings and return matter and energy to their surroundings. Distinctions between closed and open systems depend largely upon the limits defined for isolation. However, large systems—e.g., the lithosphere, plus the hydrosphere, plus the atmosphere... 

Achievement of a sufficient input flux of drug. The achievement of sufficient input drug flux is probably the greatest challenge to designing a successful controlled release delivery system. While some controlled... 

FIGURE 4 Effects of climate and landscape topography on the concentrations and fluxes of DOC in aquatic ecosystems. Differences in the widths of the arrows indicate differences in relative fluxes of organic carbon within and between terrestrial and aquatic ecosystems. The dashed and curved arrow in the arid climate diagram indicates the potential for large evaporative concentration leading to high DOC concentrations despite relatively low input fluxes. 

The source accepts a reasonable input flux of the sample and is able to accommodate samples in the gas, liquid or solid phases. 

Fixed N is also transferred from terrestrial to marine ecosystems by riverine and atmospheric vectors, in roughly equal parts (GaUoway et al, 2004). This probably contributed no more than one quarter, and perhaps less than one eighth, of the input flux of fixed N to the pre-industrial ocean (Galloway et al, 2004). Although it has been suggested that the of terrestrial inputs sums to near 0%o (Brandes and... 

Table 3 Revised oceanic phosphorus input fluxes, removal fluxes, and estimated oceanic residence time.

The average drug input fluxes during the 20 min dosing periods between hours 24 and 25 were calculated to be 81, 108, and 138pg/h/cm for currents of 150, 200, and 250 pA, respectively. These values, the mean maximum plasma concentration values, and the total AUC values (over the same time period) for the three IDDS treatments all increased proportionally with current. These results agree with theoretical expectations expressed by [Eq. (1)]. In addition, the variabilities in the fentanyl pharmacokinetic parameters were similar for the IDDS and IV treatments, indicating that the IDDS doses were delivered with an accuracy similar to the IV infusions. 

Figure 15.16. Broecker s (1974) idealized kinetic model for the marine cycles of biologically fixed elements. volume of river water entering the ocean per year expressed as volume per unit sea area (m m yr or m yr ) = 0.1 m yr Chv, concentration of an element in average river water (mol m ) x Cnv, input flux (mol yr ) Fmix. volume of water sinking into deep water box = volume of water rising to surface water box (volume m yr ) = 2(X) m yr Q...

The foregoing discussion illustrates the variety of processes involved in hydrospheric sulfur movement. Examination of Table 6.4.3 suggests that physical processes tend to dominate in input fluxes while biological mechanisms, such as uptake by marine plants and escape of biogenic sulfide, are dominant in removal processes. 

Element Hydrothermal plume removal flux River input flux % removal of river input flux... 

Inputs - fluxes into the mantle The principal mechanism by which new material is added to the mantle is subduction. The results of seismic tomography have shown that the mass flux into the mantle at subduction zones, at least in part, penetrates... 

Fig. 6.18 (a) Variation of atmospheric CH4 concentration with input flux (from methanogenesis) for varying 02 levels (controlling oxidative destruction), (b) Influence of atmospheric methane on mean surface temperature (assuming constant 02 and C02 levels, but different solar luminosity relative to present (S/S0)) during the Palaeoproterozoic (2300Ma) and Neoproterozoic (700Ma). (After Pavlov et al. 2003.)... 

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