Natural feeding regimes

We shall cover compounds with which animals come into contact because of their inclusion in diets and their administration by man, as well as those that the animals encounter as a consequence of their natural feeding regimes. 

GAMBOA-DELGADO J and LE VAY L (2009) Artemia replacement in co-feeding regimes for mysis and postlarval stages of Litopenaeus vannamei Nutritional contribution of inert diets to tissue growth as indicated by natural carbon stable isotopes. Aquaculture 297(1-4) 128-135. 

The design of any real pervaporation and vapor-permeation installation has thus to be based on experimental data measured in the laboratory under conditions as similar as possible to those of the subsequent full-size plant. These conditions include the flow regime of the feed mixture, the temperature and the geometry of the feed side, the composition and nature of the feed mixture, the permeate side geometry and partial vapor pressure. From the experimental data the partial transmembrane fluxes of all components of a mixture and thus the selectivity can be determined as a function of composition, temperature and permeate-side conditions for the respective mixture and geometry. In practice the permeate-side conditions (total pressure, condensation temperature) are kept as close as possible to those expected in the final plant, thus changes of these parameters do not need to be considered. Figure 3.3 depicts the partial fluxes of EtOH and water measured for a PVA-membrane. 

Experiments were monitored by measuring the conductivity of the feed and strip streams. The transport of ions (cobalt and iron) from an acidic feed (HCl) to a basic strip solution (NH4OH) was accomplished. Their results suggest that there are three distinct transport regimes operable in the membrane. The first occurs at short times and exhibits very little ion transport. This initial time is termed the ion penetration time and is simply the transport time across the membrane. At long times, a rapid increase in indiscriminate transport is observed. At this critical time and beyond, there are stability problems that is, loss of solvent from the pores leading to the degradation of the membrane and the formation of channels that compromise the ion selective nature of the system and its barrier properties. 

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