Palm oil methyl ester (PME) has attracted attention as a green fuel because of its stable supply. In this study, candidates for a PME surrogate fuel were selected with good imitation characteristic and repeatability for real fuel, and a PME surrogate model with excellent predictability of combustion performance was explored to perform a universal evaluation of their combustion performance through numerical simulation. Methyl esters exhibit similar combustion characteristics regardless of their carbon chain length. Therefore, linear methyl esters such as methyl butanoate (C₅H₁₀O₂), methyl octanoate (C₉H₁₈O₂), and methyl decanoate (C₁₁H₂₂O₂) were selected as candidates for the PME surrogate fuel because they are readily available and have a gross heat value similar to real PMEs. In addition, the ignition delay time and laminar flame speed of each methyl ester in the detailed reaction mechanisms were compared for the specification of the PME surrogate model. As a result, the detailed reaction model of methyl octanoate constructed by Dayma et al. (2011) was found to have the closest value to the experimental value for the ignition delay time. Then, as a result of comparing the laminar flame speeds, the reaction model for methyl butanoate constructed by Gail et al. (2007) was found to be the closest to the trend obtained from the experimental results with respect to the laminar combustion rate.

To clarify the effect of coexisting bacteria on the growth of the blue-green algae S. platensis, coexisting bacteria were isolated from S. platensis medium and identified. Bacillus pseudofirmus and Halomonas sp. coexisted with S. platensis. The specific growth rate of S. platensis without coexisting bacteria decreased in both the cases of photoautotrophic and heterotrophic cultures. The specific growth rate of S. platensis was restored when adding coexisting bacteria. In the case of the heterotrophic culture, coexistence of Halomonas sp. is desirable to increase the maximum growth of S. platensis.

Disodium hydrogen phosphate dodecahydrate is a promising candidate for latent heat storage material due to its fast crystal growth rate and high heat storage density per unit volume. In its practical application, however, a key technical problem has been to eliminate the formation of phase segregation and concentration polarization owing to the cyclic operation of heat storage and heat release. In the present study, in order to understand the influence of the formation of such phase segregation and concentration polarization on the heat release behavior of the heat storage material, the dodecahydrate melt samples formed them were prepared artificially and their solidification behavior were observed directly by eye. Additionally, the crystal growth rates of the dodecahydrates were measured and the features of each solidification behavior were evaluated quantitatively. As a result, the crystal growth rates were dropped to about 40% in both cases of the dodecahydrate melt diluted by phase segregation and the upper layer of the melt diluted by concentration polarization. Further, in another case of the lower layer of the melt concentrated by concentration polarization, the growth rate was depressed to about 20%. It was suggested that the formation of phase segregation and concentration polarization brought about not only a latent heat reduction, but also a heat releasing speed depression.