In-situ tests

This paper reports experiences and developments gained on the testing-system NFUS2300 [Ref. 6]. It will show the advanced state of the used technique and present a successful in-situ testing. 

Mechanical and chemical methods for qualitative and quantitative measurement of polymer structure, properties, and their respective processes during interrelation with their environment on a microscopic scale exist. Bosch et al. [83] briefly discuss these techniques and point out that most conventional techniques are destructive because they require sampling, may lack accuracy, and are generally not suited for in situ testing. However, the process of polymerization, that is, the creation of a rigid structure from the initial viscous fluid, is associated with changes in the microenvironment on a molecular scale and can be observed with free-volume probes [83, 84]. 

Lukowsky, D., Buschelberger, F. and Schmidt, O. (1999). In situ testing of the influence of melamine resins on the enzymatic activity of basidiomycetes. International Research Group on Wood Preservation, Doc. No. IRG/WP 99-30194. 

It is important to note that Vie and Kjelstrup [250] designed a method of measuring fhe fhermal conductivities of different components of a fuel cell while fhe cell was rurming (i.e., in situ tests). They added four thermocouples inside an MEA (i.e., an invasive method) one on each side of the membrane and one on each diffusion layer (on the surface facing the FF channels). The temperature values from the thermocouples near the membrane and in the DL were used to calculate the average thermal conductivity of the DL and CL using Fourier s law. Unfortunately, the thermal conductivity values presented in their work were given for both the DL and CL combined. Therefore, these values are useful for mathematical models but not to determine the exact thermal characteristics of different DLs. 

The stack level in situ testing in simulated driving cycle conditions for 2,000 h indicated that the plates had good comparable performance with machined graphite plates. 

Chen, C. J. (1992a). In situ testing and calibration of tube piezoelectric scanners. Ultramicroscopy, 42-44, 1653-1658. 

Plodinec, M. J. Wicks, G. G. 1994. Application of hydration thermodynamics to in-situ test results. In Barkatt, A. Van Konynenbourg, R. A. (eds) Scientific Basis for Nuclear Waste Management XVII. Materials Research Society Symposia Proceedings, 333, 145-157. 

When both of the above solutions are too much of an investment, we will have to go to in situ testing of the valves, which is also for spring-operated valves sometimes a cumbersome and expensive solution. Different service organizations offer the in situ testing on spring valves. Most are based on the same principle where set pressure is actually calculated based upon an external force applied on the spring (hydraulic or pneumatic). 

While some systems for performing in situ testing of spring-operated SRVs differ slighdy, most are based on the same principle and we will explain the principle of one of them (Figure 10.18). For all of them it is always required to know exacdy ... 

In situ testing principle of spring-operated valves... 

Test benches generally provide a relative accurate test pressure but of course are tested on CDTP and not on actual service conditions. On the other hand, in situ testing is based on calculations with several variables that need to be all measured correcdy at the exact same time. 

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