Interdigitated channels

A microreactor was also applied to this reaction. The slit interdigital micromixer was purchased from IMM (Mainz, Germany). The width of the interdigital channels is 25 pm. HPLC pumps were used to feed the two reaction solutions. One is a mixture of Boc-AMP and 1.2 molar equivalents of r-BocaO. The other is a 50% aqueous KOH solution. The microreactor was immersed in a temperature controlled cooling bath at 15 °C. The product was quenched with an acid, and samples were taken for HPLC analysis. 

Kramer et al. [272] used this same technique to compare two different flow field designs— inferdigifafed and serpentine— and their interactions with the cathode diffusion layer. If was shown thaf the bottom of the interdigitated channels got plugged with liquid water that was not removed properly. On the other hand, the serpentine FF could transport the water inside the channels more effectively, but inside the cathode DL accumulation of wafer was still evident. 

Transparent fuel cells are also common tools used to visualize and observe the water accumulation inside FFs and on the surfaces of diffusion layers. Liu, Guo, and Ma [227] tested interdigitated and parallel flow fields wifh CFP DLs. It was observed that the former FF design enhanced the mass transfer when the gas flow was forced to pass through the DL. In fact, the water flooding areas in the interdigitated channels were substantially smaller than in the parallel channel. 

Reactor 9 [R 9] Chip System with Triangular Interdigital Micro Mixer-Reaction Channel... 

This system is a chip version of three dimensional micro mixer-tube reactor setups [21]. It comprises a triangular interdigital micro mixer with a focusing zone that thins the multi-lamellae and a subsequent reaction channel that is surrounded... 

Figure4.9 Chip system with triangular interdigital micro mixer-reaction channel. First- (top) and second- (bottom) generation reactor designs [22],...

Figure 4.18 Left interdigitated micro channels made by ASE (inlay for 3-D device).

Right cut through the top part of the housing of the slit interdigital 3-D micro mixer comprising the slit-type focusing zone and the subsequent small channel to the outlet [40, 41). 

Interdigital micro mixers comprise feed channel arrays which lead to an alternating arrangement of feed streams generating multi-lamellae flows [39 2]. If processes have to be carried out with extended residence times (> 1 s) and/or at a temperature level different from the mixing step, tubes have to be attached to the interdigital micro mixers. Their internals comprise millimeter dimensions or below, if necessary. 

GL 22] [R 3] [R 9] [R 10] [P 23] The mass transfer efficiency of different gas/liquid contactors as a function of residence time was compared qualitatively (Figure 5.29), including an interdigital micro mixer, a caterpillar mini mixer, a mixing tee and three micro bubble columns using micro channels of varying diameter [5]. 

Fig. 4.4 Pore-filling models for protein adsorption in a mesopore channel (a) separated single-molecularadsorption (b) separated double-molecular adsorption (c) separated triple-molecular adsorption (d) interdigitated triple-molecular adsorption where adjacent layers are interdigitated by 1/4 of the protein diameter through changing the relative orientation. Adapted from [37],...

Figure 12.10. Micrographs of devices fabricated using gravure printing technology. Left—shows the interdigitated transistor gate fabricated by an ink composed of nanoscale metallic particles. Right—Channel fabricated when using a silver-filled adhesive to print the transistor source and drain.

An optimum relationship between the DL and the flow field channels is a key factor in the overall improvement of fhe fuel cell s performance at both high and low current densities. Currently, flow field designs are typically serpentine, interdigitated, or parallel [207,264]. The FF plate performs several functions If is a current collector, provides mechanical support for the electrodes, provides access channels for the reactants to their respective electrode surfaces and for the removal of producf water, and it prevents mixing of oxidant, fuel, and coolant fluids. 

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