<p>Odor discrimination ability was tested in four female South African fur seals (<em>Arctocephalus pusillus pusillus</em>) using a food-rewarded two-choice instrumental conditioning paradigm. The seals’ ability to distinguish between members of homologous series of aliphatic ketones (2-butanone to 2-heptanone) and alcohols (1-butanol to 1-heptanol) was assessed. The results showed that three out of four seals successfully discriminated between all of their stimulus combinations in both classes of odorants. One seal succeeded to reach the discrimination criterion with all 2-ketones but failed with all 1-alcohols.</p><p>No significant correlation between odor discrimination performance and structural similarity of the odorants in terms of differences in carbon chain length was found in either of the two chemical classes. Furthermore, it was found that the 2-ketones were significantly better discriminated than the 1-alcohols. The fact that both classes of odorants are known to be present in the natural environment of seals provides a possible explanation as to why most of the seals were able to successfully discriminate between them. The results of the present study support the notion that the sense of smell may play an important role in behavioral contexts such as social communication, foraging and reproductive behavior of fur seals.</p>

Odor discrimination ability was tested in four female South African fur seals (Arctocephalus pusillus pusillus) using a food-rewarded two-choice instrumental conditioning paradigm. The seals’ ability to distinguish between members of homologous series of aliphatic ketones (2-butanone to 2-heptanone) and alcohols (1-butanol to 1-heptanol) was assessed. The results showed that three out of four seals successfully discriminated between all of their stimulus combinations in both classes of odorants. One seal succeeded to reach the discrimination criterion with all 2-ketones but failed with all 1-alcohols. No significant correlation between odor discrimination performance and structural similarity of the odorants in terms of differences in carbon chain length was found in either of the two chemical classes. Furthermore, it was found that the 2-ketones were significantly better discriminated than the 1-alcohols. The fact that both classes of odorants are known to be present in the natural environment of seals provides a possible explanation as to why most of the seals were able to successfully discriminate between them. The results of the present study support the notion that the sense of smell may play an important role in behavioral contexts such as social communication, foraging and reproductive behavior of fur seals.

Membrane processes have received growing attention due to their low energy consumption and ease of operation. Thin-film composite reverse osmosis membranes based on polyamides are the most widely applied commercial membranes, because of their high flux and selectivity. However, their application for gas separation processes is still limited. This is the due to the presence of defects in the membrane when in the dry state. Traditionally, thin-film composite membranes are made by interfacial polymerization between a polar (aqueous) phase and a non-polar (organic) phase. The most commonly applied thin-film composite membranes are made by dissolving m-phenylene diamine in the aqueous phase and trimesoyl chloride in the organic phase. This work investigated the possibility of fabricating thin-film composite membranes when an aliphatic alcohol (methanol, ethanol or isopropanol) is used as the polar phase. This is further extended to examining the ability of a PDMS coating to plug the defects in such layers. The effects of temperature and support type on the membrane performance were also studied. Solubility tests were conducted to determine the solubility limit of commercial and in-house fabricated amine monomers in water, methanol, ethanol and isopropanol. Water-insoluble monomers were found to be soluble in ethanol and methanol. Gas permeation tests were conducted on membranes made using water, methanol, ethanol and isopropanol as the polar phase. The results showed that the membranes produced by aliphatic alcohols had higher selectivities. The highest H2/CO2 selectivity of ~ 26 was observed in the ethanol-based membranes when they were coated with PDMS and tested at 80 C. It was confirmed that PDMS is able to plug the defects in the membrane. Membranes made on the polysulfone support were found to have higher permeance and comparable selectivity relative to the membranes made on the polyacrylonitrile supports. It was also found that a change in the polar phase solvent is able to alter the morphology of the membranes. SEM micrographs showed clear differences in the surface structure of each membrane. The average thickness values obtained from ellipsometry measurements showed a correlation with the interface miscibility. The thickest membrane corresponded to the most miscible interface (IPA/Isopar).