Urea was added in the thermal formation systems of various rare earth phosphates, orthophosphate, pyrophosphate, polyphosphate, and ultraphosphates, prepared from rare earth compounds (oxide and carbonate) and phosphoric acid. The addition of urea gave rare earth orthophosphate larger specific surface area. In the formation systems of condensed phosphates, the addition of urea promoted the dehydration condensation reaction of phosphates. In cerium salts, which were expected to have the different thermal behavior from other rare earth phosphate because of exsistence of tetravelent cerium cation, the formation of tetravalent cerium phosphates was suppressed by the addition of urea.
A meteorological radar system with functions of polarimetric observation has been expected to be useful to meteorological fields. In this report, we evaluated the performance of such radars by computer simulations. We examined the performance of rain observation by a X-band dual-polarized radar. Although attenuation caused by rain at X-band was relatively large, deterioration in accuracy of the polarimetric observation was small as far as width of a region with intense rain of 20 mm/h was narrower than 20 km. These results are expected to be useful to the future design of high performance meteorological radars.
The vertical multiple-effect diffusion-type solar still, which consists of a number of vertical parallel partitions in contact with saline-soaked wicks with narrow gaps between partitions, coupled with a heat-pipe solar collector has a great potential because of its high productivity and simplicity. We performed the indoor experiments of a heat-pipe solar collector, which can be applied for this type of still, to determine the actual boiling behavior in the evaporating tubes attached to the solar collector plate, and found that the temperature difference between the solar collector plate of the solar panel and the first partition plate attached to the condensing path was about 5 to 8 K. The results were in good agreement with the numerical simulation of the proposed still, and indicate that the heat-pipe solar collector can transport thermal energy well from the solar collector panel to the multiple-effect still. Further, it was found that small amount of working fluid in the evaporating tubes causes the dry patches on the inner surface of the evaporating tubes, which causes serious damage to the heat-pipe solar collector plate.
We proposed a small distiller using wind energy for maritime lifesaving. The distiller consists of a wind turbine and a number of cylindrical partitions in contact with saline-soaked wicks. The shaft energy from the wind turbine is transported as the frictional thermal energy of a liquid heat medium to the distilling section, where the energy is recycled to increase the production rate of the distillate. The performance of the distiller was analyzed theoretically, and we found that the distiller can produce 1.7kg a day with 6 m/s wind velocity, a 0.6m wind turbine rotor diameter, a 5mm diffusion gap and 4 distillation cells. The amount of fresh water is enough to meet the requirement of one person in one day. The maximun amount of distillation is 4kg with 6 m/s wind velocity, a 0.6m wind turbine rotor diameter, a 3mm diffusion gap and 11 distillation cells.
Many streams on Kureha Hill, located in Toyama City, Japan, are believed to suffer from nitrogen saturation because of their high concentrations of nitrate. We tried to simulate the flow-path change and the nitrate dynamics within the soils of one of the watersheds by using a flow-path model in order to identify the factors regulating the nitrate concentration of the stream. The result from the model implied that the lateral flow containing extremely high concentration of nitrate from the sub-surface soil strongly affected the nitrate concentration of the stream water. The flow-path model also showed no seasonality in the nitrate concentration of the stream water after eliminating the effect of the flow-path change within the soils on the nitrate concentration of the stream water. This result well coincided with Stoddard's definition of nitrogen saturation in the respect that no seasonality would be found in the deep stage of nitrogen saturation.
In order to collect both rain and snow samples with a single collector, heating apparatuses were installed to two types of conventional precipitation collectors utilized in Japan :(1) Wet-only collector equipped with a sliding roof to collect wet and dry depositions separately, (2)Bulk 1 collector composed of a funnel, a filtration unit and a bottle. The heating apparatuses were equipped to both the collection funnel unit and the glass-made filtrating unit of the collectors so that the units were kept at 5±1°C for melting snow on the funnel and minimizing the possible evaporation. In addition, (3)Bulk 2 collector, which was particularly designed for collecting snow by a cylindrical bag, was examined on its performances. Collection efficiencies of precipitation of these three collectors were compared with an authentic rain gauge. Major ion concentrations were compared among the samplers. Collection efficiencies of precipitation of these collectors showed remarkable agreements with the authentic rain gauge. The concentrations of major ions of samples collected with Bulk 1 and Bulk 2 collectors showed slight differences with Wet-only collector: Bulk 1 yielded higher concentration of calcium ion and Bulk 2 showed higher levels in ammonium, sulfate, nitrate, calcium, and potassium ions. These differences, however, are not surprising because depositions of gaseous and particulate species onto the collection funnel during the dry period from the atmosphere would be intrinsic for the bulk collectors. The heating apparatus did not affect the chemical congruity of the precipitation samples in spite of the above differences. The collectors with heating apparatus would be free from the potential bias associated with alternating a conventional rain collector and a bulk-type snow collector before and after the snow months.