Lateral area wicking

Membranes have been developed that possess improved characteristics with respect to their lateral wicking and spot resolution. The best example of this type of material is anodically oxidized alumina whose structure consists of pores, with very little material forming the walls, possessing a surface area ratio of approximately 500 f. The benefits of this material are its higher sensitivity (more immobilized capture probe) and higher probe densities. 

The behavior of liquids in narrow tubes is one of the most common examples in which capillary forces are involved. It will be shown later how important this phenomenon is in many different parts of everyday life and technology. In fact, liquid curvature is one of the most important physical surface properties that requires attention in most of the application areas of this science. The range of these applications is from blood flow in the veins to oil recovery in the reservoir. Properties of fabrics are also governed by capillary forces (i.e., wetting, etc.). The sponge absorbs water or other fluids where the capillary forces push the fluid into the many pores of the sponge. This is also called wicking process (as in candlewicks). 

Dow Chemical Co., Asahi Chemical Co. and Chloride Engineers Ltd. make a similar product. The polymer membrane only conducts H" " when fully hydrated and one solution to this problem has been to use carbon fiber wicks (Figure 23.9). SGL Carbon is making fiber based gas diffusion layers in a roll form. The cell is sensitive to low levels of CO, which can be removed by a Pt/Ru catalyst, but the high cost restricts use. However, a later technique to increase the surface area has reduced the cost by a factor of 75. 

In the Table 16.3, it can be observed that the barren land in Indonesia was increased from 9.3 Mha in 1980 to 13.3 Mha in 2005. Surprisingly, it was found that these lands were from the forest areas of Sumatra and Kalimantan. The fact is that these lands were occupied by local farmers for their agriculture and later, they were abandoned due to soil infertility, as reported by the Global Assessment of Human-Induced Soil Degradation (Wicke et al., 2008). 

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