The thermal decomposition mechanism of bivalves and sea urchin spines was investigated to evaluate the potential for using fishery waste material as thermal storage material. The thermal decomposition rate demonstrates an Arrhenius-type temperature relationship. Compared with a CaCO3 reagent, shells and spines were efficiently thermally decomposed. Despite showing a significant difference in thermal decomposition rate, chemical composition, particle size, and specific surface area, the activation energy of thermal decomposition was only marginally different. The rate-limiting process in thermal decomposition processes could be caused by the CO2 gas flux, which was emitted from the sample. The CO2 flux is controlled not only by the geometric surface area, particle seize but also by the crystallographic morphology of the sample. The biologically originated calcite may have efficient heat exchangeability as thermal storage material due to its unique crystal figure and microstructure.
As a highly sophisticated strategy for environmental control in greenhouses, the concept of Speaking Plant Approach (SPA) has attracted a great deal of attention. Sensor-based plant diagnosis techniques to monitor plant physiological status are the first and most important step in SPA. In these decades, camera modules have become low-cost, and IoT and robotics technology have become commonplace, therefore imaging devices for monitoring plant growth are becoming a common tool in commercial greenhouse. In this study, we developed a hanging type multiple biological information imaging robot that able to be installed in commercial greenhouses. It measures color, chlorophyll fluorescence, red light reflection, and far-red light reflection images at any part of the plant canopy with the horizontal and vertical movement unit (red and far-red reflection images are used for the calculation of NDVI image).
To assess the stability of the developed robot, the robot was installed in a tomato production commercial greenhouse and applied for a long-term measurement of the 3.5 m high and 56 m width tomato canopy. The results showed that the robot successfully obtained color and chlorophyll fluorescence panoramic images of the whole area of the tomato canopy over consecutive 30 days. And they proved that the developed robot has enough stability to obtain the multiple biological information images of a plant canopy in commercial greenhouses and there are some refinement points such as frame skipping during the video acquisition and tire slipping of the rail-runner unit for horizontal movement.