Long-term durability tests

Heim F and Gupta B (2009), Textile heart valve prosthesis The effect of fabric construction parameters on long term durability , Text Res J, 79,1001-1013. Heim F, Durand B and Chakfe N (2010), Textile for heart valve prostheses Fabric long-term durability testing , / Biomed Mater Res B, 92 (1), 68-77. 

During S-cell stack performance test, the reformed gas with 6,820 seem flow rate and air with 13,000 seem rate were respectively used as fuel and oxidizer gas to complete l-V-P and durability tests. The reformed gas generated from methane and water vapor through the home-made reformer installed in the SOFC measurement system. According to our experiences about measuring the degradation rate of SOFC MSC cell stack, the most suitable applied current density is located around 400 mA/cm at 700 C. So, the constant current density is kept at 400 mA/cm in long term durability test. 

In Eq. (I), the Vj, Vrand t refer to initial cell voltage, final cell voltage and operating time (in hours) in long term durability test. 

Figure 8. Long-term durability test results of single-cell MSC stack with hydrogen.

High-density polyethylene (PE-HD) Hostalen CRP 100 Black, MFR = 0.23 g/10 min (190 °C/5.0 kg), the soot content of 2.25%, prod. Basell Olefins was used as the matrix polymer. This PE-HD is a bimodal polyethylene, whose structure is characterized by the presence of two fraction of different molecular weight of polymer. Bimodal structure of PE-HD has a beneficial effect of its mechanical properties during long-term durability test. Higher resistance of this PE-HD to mechanical action as compared to other polyethylenes makes it suitable for use in the construction of various pipelines where it is important that the mechanical properties are a function of time as high as possible [27]. 

Heim, F., Durand, B., Chakfe, N. Textile for heart valve prostheses fabric long-term durability testing. J. Biomed. Mater. Res. B Appl. Biomater. 92, 68-77 (2010). doi 10.1002/jb m.b.31490... 

A long-term durability test with a optimized reP-25-based membrane showed 4,000 h of continuous operation under moderate conditions 500 mA cm" with a cell temperature of 80-85°C, H ( 100% RH)/Oj(dry) under ambient pressure (Gubler et al. 2004). The final lifetime reached 7,900h, where the membrane degradation was accelerated by several controlled/uncontrolled startup/shutdown cycles. 

The major degradation factors of the MEA for the residential PEFC system discussed in the previous sections are based on the results of long-term durability tests. However, during such long-term tests, the improvement of materials used in the... 

Fig. 12 The change in the voltage of MEA during the long-term durability test. The experimental conditions are the same as for Fig. 2 except for the gas composition of the fuel...

After a long-term durability test, over 500 hours, SEM images of the electrode surface were measured, which were compared with the ones obtained before the durability test. Surface topography and the hole diameter hardly changed before and after the electrolysis (Fig. 24.7 (a) and (c)). However, the edges of the holes appear to be slightly shaved off and rounded (Figure 24.7 (b) and... 

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