Satoshi Yoshida

Temporal Analysis of Water Quality of the Kaname River Basin Using GIS

Abstract The authors analyzed the water quality of five rivers in the Kaname River basin and correlated it with the sewerage system and land use. The development of a sewerage system and reduction in agricultural land were found to affect water quality. The water quality of all river basins improved with time, and the improvement was seen as a gradual reduction in the pollution loads from the unsewered population and agricultural land. Temporal variations in the water quality of each river could be used to characterize them in terms of the expansion of the sewerage system and decrease in agricultural land use. Multiple regression analysis revealed that, in most cases, the unsewered population had a greater impact on water quality; nevertheless, the change in agricultural land use also had some influence. Unlike total nitrogen (TN), chemical oxygen demand and total phosphorus exhibited good correlations with the pollution loads from the unsewered population and agricultural land. Atmospheric nitrogen (N) was presumed to impact the TN concentration in rivers. To maintain the water quality in the Kaname River basin, the development of a sewerage system could be a crucial factor; however, the contamination due to atmospheric N also needs to be considered.

Methods and Techniques for Promoting a Multidisciplinary Environmental Research Project using GIS

This study demonstrates collaborative methodologies and techniques using GIS (Geographic Information System) for multidisciplinary environmental research by self-evaluating trialand-error practices in a multidisciplinary research and education program at Yokohama National University (YNU). It describes changes of the activation level of GIS use throughout the overall and individual research projects in the program. This study analyzes the trigger factors by conducting interviews of participating researchers. As a conclusion, it proposes new ideas to promote a multidisciplinary environmental research project that makes use of GIS. Experiences and lessons learned from this program are useful for designing and implementing new multidisciplinary environmental projects beyond YNU and Japan.

Study on Running Performance of a Split-type Air Conditioning System Installed in the National University Campus in Japan

Abstract Split-type air conditioning systems, or heat pump systems with multiple indoor and outdoor units, are becoming very popular for room cooling and heating of small or middle-sized non-residential buildings in Japan. However, their running performance is yet to become known due to the difficulty of measuring the actual amount of heat transferred by the system. Mixed irregular flow of vapor and liquid refrigerant prevents building engineers from obtaining accurate heat flow data between indoor and outdoor units. This study introduces an alternative method to calculate heat transferred by the system from air volume and enthalpy measured with simple sensors attached to the indoor units. Experimental results on a national university campus in suburban Tokyo showed unexpectedly low COP values both in summer and winter mainly due to the prevailing low partial load factors under 20-30% of the system capacity.