45 research outputs found
Fractal Nanotechnology
Self-similar patterns are frequently observed in Nature. Their reproduction is possible on a length scale 102–105 nm with lithographic methods, but seems impossible on the nanometer length scale. It is shown that this goal may be achieved via a multiplicative variant of the multi-spacer patterning technology, in this way permitting the controlled preparation of fractal surfaces
Wettability Switching Techniques on Superhydrophobic Surfaces
The wetting properties of superhydrophobic surfaces have generated worldwide research interest. A water drop on these surfaces forms a nearly perfect spherical pearl. Superhydrophobic materials hold considerable promise for potential applications ranging from self cleaning surfaces, completely water impermeable textiles to low cost energy displacement of liquids in lab-on-chip devices. However, the dynamic modification of the liquid droplets behavior and in particular of their wetting properties on these surfaces is still a challenging issue. In this review, after a brief overview on superhydrophobic states definition, the techniques leading to the modification of wettability behavior on superhydrophobic surfaces under specific conditions: optical, magnetic, mechanical, chemical, thermal are discussed. Finally, a focus on electrowetting is made from historical phenomenon pointed out some decades ago on classical planar hydrophobic surfaces to recent breakthrough obtained on superhydrophobic surfaces
An Improved Mathematical Simulation of the Coupled Diffusion of Moisture and Heat in Wool Fabric
Influence of pores on wetting of alumina- and zirconia-base ceramics by molten manganese
Wear Mechanisms of Carbon-Based Refractory Materials in SiMn Tap-Holes—Part II: In Situ Observation of Chemical Reactions
The purpose of the study presented here is to determine to what extent chemical reactions
between carbon-based refractory and slag or metal in the tap-hole of a SiMn furnace can
contribute to wear of tap-hole refractory. The results of the study are reported in two parts. In
Part I, thermodynamic calculations suggested that reaction between silicomanganese slag and
carbon-based tap-hole refractory is possible, and experiments with nominally pure materials
support this. However, practical refractory materials are by no means pure materials and
contain secondary phases and porosity which can be expected to affect reaction with slag. In
Part II, such reactions are examined experimentally, in cup and wettability tests, using commercially
available carbon block and cold-ramming paste refractory materials and mainly
industrial SiMn slag. Clear evidence was found of chemical reaction at approximately 1870 K
(approximately 1600 C), forming SiC and, it appears, metal droplets. Both carbon block and
ramming paste refractory reacted with slag, with preferential attack on and penetration into the
binder phase rather than aggregate particles. The two types of carbon-based refractory materials
showed similar extents of chemical reaction observed as wetting and penetration in the laboratory
tests. The differences in refractory life observed practically in industrial furnaces should
therefore be attributed to wear mechanisms other than pure chemical wear as studied in this
work.National Research Foundation of South Africa (Grant TP2011070800005).http://link.springer.com/journal/116632016-04-30hb201