Segmented anode

Figure 4-43. General schematic of a wall-stabilized arc with segmented anode.

The Segmented Anode Parallel Channel PEM Fuel Cell... 

Figure 3.5A. Segmented anode fuel cell. The flow channels and divisions of the anode are shown. The basic setup for temperature control, reactant feed, and relative humidity and water flow measurements for the segmented anode fuel cell was the same as the one employed with the differential PEM fuel cell.

Figure 3.5B. Equivalent circuit for the segmented anode fuel cell. The current through each segment, as well as the voltage drop across the load resistance, were monitored. The voltage across the load resistance was recorded, as well as the currents through the six segments of the anode. The total current was determined by summing the individual currents through the six segments of the anode.

Figure 3.8. Ignition in segmented anode PEM fuel cell with co-current (left) and counter-current (right) flow. The color intensity represents the local current at the anode. In co-current flow (A) the current ignites after 1.5h at the exit to the flow channels and propagates upstream to the flow channel entrance. The steady state current profile (C) is stable after 6 h, with the current decreasing from the inlet to the exit. In counter-current flow (B) ignition first occurs at the center of the flow channels after an induction period of 7 h. The current density fans out over time. After 10 h, the steady state current profile (D) shows the highest current at the center with the current declining at either end of the fuel cell.

Two model fuel cell reactors, the stirred tank reactor- polymer electrolyte membrane fuel cell and the segmented anode parallel channel fuel cell, have been shown to be effective in the study of PEM fuel cell dynamics. Simplified... 

Gas ionization detectors are popular for identification of heavy ions in AMS measurement. They are simple to design and operate, and come in different shapes and sizes. Such a detector is basically a gas-filled enclosure, which contains two electrodes. The electrodes maybe of different types parallel plate, coaxial cylinder, segmented anode, etc. depending up on the purpose of use. When an energetic heavy ion enters the detector, it ionizes gas atoms during its travel. As a result, electron-ion pairs are generated, which are separated and collected by a transverse electric field. The entrance window of the detector is a thin Mylar film ( -150-300 pg/cm ). 

Cross-sectional view of a segmented-anode gas ionization detector... 

Constructing Each Segment The objective in this case is to make a four-segment anode from carbon fabric, with each segment measuring 0.5 m x 1 m. This segmented anode will be rolled onto an axle within the sled and deployed as... 

To collect current from the segmented anodes, copper flat wire is run to each anode segment and is electrically connected to the fabric with stainless steel staples. Installation of insulated copper flat wire is described as follows and depicted in Figure 11.7. The goal here is to create good, waterproof electrical contacts between the carbon... 

---