Production of crushed stone and crushed sand used as aggregate for concrete is classified into two types, dry process type and wet process type. In the dry process type, a large amount of crushed stone powder is produced as a by-product. In 2009, crushed stone powder was standardized by JIS A 5041. However, there is no discussion on the utilization method and the specific surface area of the crushed powder satisfactory. In this study, we made many types of mortar with different mix proportion. The mortar was made from two types of crushed sands which were produced from dry process and wet process, and three types of crushed stone powders with different specific surface areas. The table flow tests were conducted to clarify the fluidity of these mortar. As a result, it was revealed that the difference in the specific surface area of the crushed powder influences the fluidity of the mortar, and in particular, the crushed stone powder having a large specific surface area deteriorated the fluidity of the mortal remarkably. Therefore, it was suggested that the upper limit which is 9%, of fine particles quantity in crushed sand (JIS A 5005) could be moderated.
The terminal pipelines of the Miyagawa irrigation network system are being clogged due to the accumulation of Asian clams. To counteract this clogging, the Miyagawa land improvement district conducts sludge discharge operations. In this study, the government-managed No. 1 main channel via a pond and the government-managed No. 2 main channel not via a pond were set as the study area. From the estimated growth curve, the growth of Asian clams in the pipeline was considered. As the result, it indicated the possibility that Asian clams were reproducing during all seasons excluding severe cold season. In addition, the water sampling were carried out in discharge operations. Some water qualities were analyzed. As the results, it was found that the pond had the effect of increasing Chl-a and DO. It was shown that Miyagawa irrigation network system provide the water quality environment suitable for the habitat of Asian clams within the pipeline. In addition, it was shown that total nitrogen, total phosphorus, and COD in the downstream increase until the middle of the irrigation period, due to the presence of Asian clams in the pipeline.
This report proposed a new definition of abnormal data in the estimation of evapotranspiration and described the applying result of the definition for the energy balance-Bowen ratio method. Namely, the abnormal data defined that the sensible heat flux (H) and the latent heat flux (lE) are α times of the applied heat flux (Rn-G) and the abnormal range of the Bowen ratio (Bo) derived mathematically. As a result, in Bo method, the definition of this abnormal data induces that Bo is equivalent to abnormal data generated in the vicinity of -1. Also, following result clarified by applying the definition to actual data, ①The evaporation rate required for water resource and irrigation planning can be obtained if α closed 1.0∼3.0 for Bo method. ②Abnormal ratio in Bo method is remarkably much in night time than day time which coincided with the many previous researchers' experiences. ③Proposed abnormal range covers all range previously proposed by researches when choosing adequate α.
This paper described the feature of lE (Latent heat flux) and H (Sensible heat flux) derived from the IABM (Inverse analysis of Bowen Ratio method), BO(Bowen ratio) method and Eddy covariance method and compared the feature among them. Above three methods are applied by the abnormal criteria that α×ABS(Rn-G)>ABS(H) and ABS(lE) as proposed by the previous research. ① The hourly changes of lE and H of the three methods are very well consistent with each other during crop growing season (α=1.0 in the IABM). ② Comparison of three set of daily data of the lE between the two methods among the IABM, BO and Eddy covariance methods shows they are very well consistent with each other. ③ Comparison of monthly change for the lE among the three methods describe very well their consistency with each other in case of α＝1.0. ④ The ratio of the abnormal data is remarkably many in the BO method than the Eddy covariance method and IABM. ⑤Monthly evapotranspiration required for water resources and irrigation planning can be estimated by the three methods sufficiently.
We conducted field surveys to clarify distribution of the wintering Nagoya Daruma Pond Frog (Pelophylax porosus brevipodus) and the environmental factors affecting wintering site of this species in a rice paddy field and an adjacent fallow paddy field in Kurashiki, Okayama Prefecture, western Japan, where the species inhabits at a high density. The majority of the wintering individuals (34 out of 35) were found in the fallow paddy field. A GLM was fitted using presence and absence of this species as the objective variable, whereas cover rate, plant height, soil pH, volumetric water content, gravimetric water content, degree of saturation, porosity, and topsoil hardness as the explanatory variables. The best model selected based on AIC consisted of soil hardness, cover rate, and the quadratic term of plant height, in which the negative effect of soil hardness was significant. The results insist on the importance of soil hardness and the presence of plants on the topsoil when creating wintering habitat for this frog species in rice paddy fields.
The nitrogen (N) removal equation for paddy fields can be used to estimate the N removal rate based on input N concentration and temperature. The objective of the present study was to focus on various temperature factors affecting the accuracy of the equation in estimating the N removal rate. The survey site was a wet paddy field in the Kanto region of Japan. It was always flooded and under non-vegetation, non-penetration conditions. The survey was carried out for about 2 years starting in January 2015. We looked at water temperature, soil temperature (at 10 cm beneath the surface) and the average integrated hourly temperature in terms of how they affect the estimation of N removal rates. The average integrated hourly temperature was determined by AMeDAS. The relationship between the calculated values and measured values were evaluated using the R2 value. It was found that the N removal rate correlated more strongly with the soil temperature at 10 cm beneath the surface and the average integrated hourly temperature than with water temperature. We introduced a temperature factor “D” to correct the removal rate. It was found that the most accurate estimation of the N removal rate was obtained when the average integrated hourly temperature was used along with a temperature correction coefficient D = 1.3.
It is essential to accumulate the case studies on the social relations formed in the process of recovering from the earthquake disaster in rural areas from a standpoint of not only considering disaster-prevention measures but also rethinking shrinking rural areas' value. This report represents the disaster restoration and revitalization model collaborating with urban residents in rural areas based on the case study on “Yamakoshi-Kogomo-furusato-kai” Group established after the Mid Niigata prefecture Earthquake in 2004 by the participant observation and interviews in FY2016. It was revealed that development of the struck houses, old elementary school site, etc. led to the interaction between urban and rural areas, the collaboration among settlements, and the interaction between disaster-affected areas, which were achieved by flexibility of the organization management and attachment of the people concerned.