The effect of graphite and carbon black ratios on conductive ink performance

Conductive inks based on graphite and carbon black are used in a host of applications including energy storage, energy harvesting, electrochemical sensors and printed heaters. This requires accurate control of electrical properties tailored to the application; ink formulation is a fundamental element of this. Data on how formulation relates to properties have tended to apply to only single types of conductor at any time, with data on mixed types of carbon only empirical thus far. Therefore, screen printable carbon inks with differing graphite, carbon black and vinyl polymer content were formulated and printed to establish the effect on rheology, deposition and conductivity. The study found that at a higher total carbon loading ink of 29.4% by mass, optimal conductivity (0.029 Ω cm) was achieved at a graphite to carbon black ratio of 2.6 to 1. For a lower total carbon loading (21.7 mass %), this ratio was reduced to 1.8 to 1. Formulation affected viscosity and hence ink transfer and also surface roughness due to retention of features from the screen printing mesh and the inherent roughness of the carbon components, as well as the ability of features to be reproduced consistently

Moisture levels and drying potential of the concrete in Swedish reactor containments

The climatic conditions inside nuclear reactor containments are continuously monitored by the plant owners in order to e.g. maintain a suitable climate for the mechanical and electrical equipment. Due to the high temperatures, during operation, the concrete within the containment may act as a moisture source contributing to the humidity. To evaluate if, and to what extent, the concrete inside the containment influences the climatic conditions, the moisture distribution has to be determined. In order to do this, a measurement setup has been developed and tested. The results showed that the measurement setup was suitable for long term measurements of internal relative humidity in concrete. However, measurements close to the concrete surfaces showed tendencies of leakage, increasing the uncertainties of those measurements. The measurement setup was installed at three reactor containments in Sweden during the summer of 2012. Results from the monitoring campaign on one of the three reactor containments are presented in this paper. The results showed that the concrete was still drying after 30-35 years of exposure inside the containment

Moisture levels and drying potential of the concrete in Swedish reactor containments

The climatic conditions inside nuclear reactor containments are continuously monitored by the plant owners in order to e.g. maintain a suitable climate for the mechanical and electrical equipment. Due to the high temperatures, during operation, the concrete within the containment may act as a moisture source contributing to the humidity. To evaluate if, and to what extent, the concrete inside the containment influences the climatic conditions, the moisture distribution has to be determined. In order to do this, a measurement setup has been developed and tested. The results showed that the measurement setup was suitable for long term measurements of internal relative humidity in concrete. However, measurements close to the concrete surfaces showed tendencies of leakage, increasing the uncertainties of those measurements. The measurement setup was installed at three reactor containments in Sweden during the summer of 2012. Results from the monitoring campaign on one of the three reactor containments are presented in this paper. The results showed that the concrete was still drying after 30-35 years of exposure inside the containment