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Fog-collecting meshes show a great potential in ensuring the availability of a supply of sustainable freshwater in certain arid regions. In most cases, the meshes are made of hydrophilic smooth fibers. Based on the study of plant surfaces, we analyzed the fog collection using various polyethylene terephthalate (PET) fibers with different cross sections and surface structures with the aim of developing optimized biomimetic fog collectors. Water droplet movement and the onset of dripping from fiber samples were compared. Fibers with round, oval, and rectangular cross sections with round edges showed higher fog-collection performance than those with other cross sections. However, other parameters, for example, width, surface structure, wettability, and so forth, also influenced the performance. The directional delivery of the collected fog droplets by wavy/v-shaped microgrooves on the surface of the fibers enhances the formation of a water film and their fog collection. A numerical simulation of the water droplet spreading behavior strongly supports these findings. Therefore, our study suggests the use of fibers with a round cross section, a microgrooved surface, and an optimized width for an efficient fog collection.

The effect of pressure on the thermal conductivity and density of olive, safflower, linseed, and castor oils in the temperature range of (283 to 333) K and pressures up to 400 MPa was studied. The thermal conductivity measurements were carried out using a transient hot-wire method with an estimated uncertainty of 2.7 mW·m−1·K−1. The density of olive oil was determined within an uncertainty of 0.3 % by a Jamin interferometer. Results reveal an increase in the thermal conductivity and density with pressure. The pressure dependency of the thermal conductivity of these plant oils correlates with the coefficient of isothermal compressibility. The temperature dependency of the thermal conductivity is linked to the isobaric thermal expansion coefficient. This agrees well with the vibrational theory of thermal conductivity due to Horrocks and McLaughlin. From this model, the relation between thermal conductivity and density λ/λ0 = (ρ/ρ0) g can be obtained. The application of our data to this relation leads to g ≈ 3, which is typical for organic liquids.

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Molecular energy transport in aqueous sucrose and glucose solutions of different mass fractions and temperatures is investigated up to 400 MPa, using the transient hot-wire method. The results reveal an increasing thermal conductivity with increasing pressure and decreasing mass fraction of sugar. No significant differences between sucrose and glucose solutions were observed. Different empirical and semiempirical relations from the literature are discussed to describe and elucidate the behavior of the solutions with pressure. The pressure-induced change of the thermal conductivity of sugar solutions is mainly caused by an increase of the thermal conductivity and the decrease of molar volume of the water fraction. A simple pressure adapted mass fraction model permits an estimation of the thermal conductivity of the investigated solutions within an uncertainty of about 3%.

The impact of different viscous substances on homogeneous thermal treatment during high pressure processes is exemplified for a cylinder piston system. Therefore, the relevant equations of thermofluid dynamics have been examined and conditions for homogeneous thermal processing have been set up. Furthermore, the analysis of an n-order inactivation kinetic delivers criteria for insensitivity of reactions to spatial temperature heterogeneities. The findings have been applied to a short time high pressure process and compared with results of numerical simulations. Good agreement could be achieved.