Structure and Performance

Parameters which are characteristic of the porous structure of the electrodes used for the measurement of the current-potential curves in Fig. 92 are given in Table 10 with performance parameters. The electrodes FC 100 and CAAl were supplied by Pure Carbon Company and American Cyanamid Company respectively, while the electrodes SM 1 and SM 2 were prepared in the laboratory [12]. 

If the parameter i/(Pt content) at 0.1 V is taken as a simple measure of the ratio between performance and cost of production, the electrode CAAl possesses the best properties. The parameter i/(Pt content) is preferred as a measure rather than content) since the latter 

The column with i/s6h values demonstrates that only a fraction of the maximum available surface participates in the H2 oxidation. Otherwise the factor of 10 by which i/sQu differs for FC 100 and SM 2 should have a greater effect on the values of the ratio i/(Pt content). While the electrode CAAl has a similar porosity as the electrodes SM 2 and SM 1 and about the same mean hydraulic diameter as SM 1, its thickness is about half the thickness of the other electrodes and the ratio (Pt con-tent)/sQH is the smallest. The same limiting current and the same current-potential curve were obtained [12] when several thicknesses of electrode were compressed and used as one electrode. This result rules out any effect of the thickness on performance and suggests [12] in connection with the small ratio ( 0.05) between the double layer capacity of the same electrode under diffusion conditions and in the flooded state for elec- 

If electron micrographs of the electrodes were available, conclusions on the desirable distribution and the size of the platinum clusters could be drawn. 

The electrode FC 100 has a small hydraulic diameter in comparison to the other electrodes. The ratio of the double layer capacities suggests that about 25 % of the internal surface of electrocatalyst is wetted. The operation of this electrode seems to differ from that of the other three electrodes in the participation of a large number of pores with relatively small radii. 

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Develop practical test program to demonstrate components ability to meet structural and performance criteria. Extent of such test program, if any, depends on economic value of component, number of units to be produced, consequences of failure, accuracy of structural analysis and design, margins of safety used in design, knowledge about service loads and environments, and difficulty of duplicating service loads and conditions in test... 

The labor-intensive nature of polymer tensile and flexure tests makes them logical candidates for automation. We have developed a fully automated instrument for performing these tests on rigid materials. The instrument is comprised of an Instron universal tester, a Zymark laboratory robot, a Digital Equipment Corporation minicomputer, and custom-made accessories to manipulate the specimens and measure their dimensions automatically. Our system allows us to determine the tensile or flexural properties of over one hundred specimens without human intervention, and it has significantly improved the productivity of our laboratory. This paper describes the structure and performance of our system, and it compares the relative costs of manual versus automated testing. 

Sholklapper et al. [204] studied the structure and performance stability of a nanoparticle-infiltrated LSM in porous scandia-stabilized zirconia (SSZ) electrode at 650°C. The infiltrated LSM particles were 100 nm in diameter and some orientation alignment of the LSM nanoparticles within SSZ was observed after the cathodic polarization at 150 mAcnr2 for 500 h. However, there is no voltage degradation under the conditions studied. 

New and promising composite pre-form technology which can be in situ molded with unsaturated polyester resins to further improve structure and performance have been demonstrated. 

Passalacqua, E., Lufrano, F., Squadrito, G., Patti, A., and Giorgi, L. Nafion content in the catalyst layer of polymer electrolyte fuel cells Effects on structure and performance. Electrochimica Acta 2001 46 799-805. 

Functions, Structures, and Performance Requirements of Bipolar Plates... 

At macroscopic level, the overall relations between structure and performance are strongly affected by the formation of liquid water. Solution of such a model that accounts for these effects provides full relations among structure, properties, and performance, which in turn allow predicting architectures of materials and operating conditions that optimize fuel cell operation. For stationary operation at the macroscopic device level, one can establish material balance equations on the basis of fundamental conservation laws. The general ingredients of a so-called "macrohomogeneous model" of catalyst layer operation include ... 

We have also shown how 2-D molecular editing can be used to identify relationships between structures and perform other analysis that would be difficult using conventional substructural perception. 

We have tried to relate the performance of a deteriorated membrane to its structure by classical methods. Recent advancement in the techniques of morphological and physicochemical analyses is remarkable, and is much contributing to better understanding of the membrane behaviour. We have now various types of RO membranes made of synthetic polymers available, and most these analytical procedures are applicable for the analysis of these membranes. Investigations on the membrane structures are much more required, and they will reveal the relations between materials and structure, and structure and performance. We believe these Investigations will contribute to development not only in the membrane Itself, but in the application of the membrane. We hope the progress of membrane science will expand RO marke t. 

Membrane morphology is studied with scanning electron microscopy (SEM) thereby providing an Insight into the relationship between asymmetric membrane preparation, structure, and performance (29,3A). The extent of ion exchange of the salt form of the SPSF membranes is studied with atomic absorption spectroscopy (AAS), neutron activation analysis (NAA), and ESCA. AAS is used for solution analysis, NAA for the bulk membrane analysis, and ESCA for the surface analysis. 

This section is an overview of device structure and performance. 

A number of bioinformatic programs can calculate the distance between RNA secondary structures and perform clustering analysis to identify ensembles of related structures (Liu et al., 2008 Torarinsson et al., 2007). Partitioning the alignment in a set of ensembles thus reduces the total number of phylogenetic variants to be considered and single representative from each ensemble can be subjected to crystallization trials. 

J. A. Knox, B. Haur, and G. R. Millward, Structure and performance of porous graphitic carbon in liquid chromatography, J. Chromatogr., 3 353 (1986). 

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