In this research, the enhancement of the pozzolanic activity of cinder ash was evaluated using pulverized raw cinder ash particles. Since the sum of SiO₂+Al₂O₃+Fe₂O₃ of pulverized cinder ash (PCA) was >70% and based on the results of XRD analysis, it could be classified as Class F fly ash (FA). Also the chemical composition and mineralogical characteristics of PCA was similar to FA. But the shape of PCA particles differed from those of FA particles, as the pulverized particles were rougher in texture and has sharp edges than FA particles, which have round shape and smooth surfaces. From the results of the mechanical properties development and compressive strength values, it could be considered that the addition of 20% PCA, as cement replacement in concrete produced the best effects. The X-ray diffraction and scanning electron microscopy techniques revealed that the PCA had satisfactory pozzolanic activity though a bit lower than FA. This is because of insufficient formation of C-S-H and C-A-S-H gels even with a high consumption of CH. The pozzolanic activity of fly ash was much greater than PCA due to the higher glassy phase and round finer particles of fly ash. Therefore, the 20% of cement content replaced by PCA was better than 30% replacement, with fly ash the 30% replacement ratio was preferred.

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The thermophilic oxic process (TOP) is an experimental alternative disposal method of treating several types of organic waste material. Previous research has certified that cedar chips are suitable intermedium for disposing of food leftovers, and that in feeding interval of 24-36 hours, the biodegradation capacity can be raised to 22.77kg·m^-3. day^-1 by the management of temperature. In this paper, we investigate the influence of different aeration rates, discuss the change of water content in the whole process, and suggest a new view about natural immobility of cells. In addition, we provide results for a batch of experiments conducted to explain the aforementioned conjecture. The following points were derived from this study:(1) The aeration rate had an obvious influence on the disposal of leftovers during TOP: low aeration rate (0.05 m³·m^-3·min^-1) could not supply enough oxygen. On the other hand, surplus aeration rate (0.15 m³·m^-3·min^-1) caused heat loss and increased reactor running costs. When the BOD volume load (BVL) was 4.0 kg·m^-3·day^-1, 0.10 m³·m^-3·min^-1 was a suitable aeration rate;(2) When the BVL was 4.0 kg·m^-3·day^-1 and the aeration rate was 0.10 m³-m^-3-min^-1, the water content of the intermedium changed from 45.6% to 38.4% while the biodegradation rate was as high as 88.4%;(3) Because bio-heat generated during TOP evaporated the water, the water content stabilized at about 40% in a running reactor. However when feeding was interrupted, the water content decreased to 31.8% after 15 days, remaining there even 60 days later;(4) When feeding supply was resumed, under suitable conditions that aeration rate was 0.10 m³·m^-3·min^-1and water content was adjusted to 50%, the reactor temperature rose over the room's temperature for 5°C after 5 hours and reached to 50° after 26 hours-reactor activity was efficiently revivified.

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Over the past few decades, a considerable number of studies that generate an optimal structure under a loading and boundary condition have been made and Evolutionary Structural Optimization (ESO) method is one of the most effective techniques. The mathematical model is based on the remodeling (self-organization) of biological systems such as a bone and a tree. There have been some weak points where a reasonable solution cannot necessarily be concluded in it.
A new method (R-ESO method) that consists of three optimization processes, that is, the removal process, addition process and growth process is proposed and some simple numerical examples show the effectiveness of the method. Also, it is applied to optimizing the structures of concrete dams, and the obtained final solutions are similar to the shape of an existing concrete dam with satisfying the stable condition.

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Rice husks are frequently used as envelope and filler material for subsurface drainage in Japan. Recently, occurrence of deep slots along the subsurface drainage caused by decomposition of rice husk filler are getting apparent, requiring coping with the problem. The objectives of this study are to clarify the state of decomposition of rice husk filler in clayey paddy fields and to estimate the influence of them on the formation of gapping voids and efficiency of drainage. The rice husk fillers were sampled at 38 plots of clayey paddy fields which were selected considering the year and the ward of subsurface drainage installation and history of cultivation. Decomposition Index (DI), Filtered Soil Content (FSC), and in-situ dry bulk density were measured for the samples. The degree of decomposition depends on the ward as well as the year after the installation, but does not on the history of cultivation. Although FSC increases with the year after the installation of subsurface drainage, it is not observed that the filtered soil seriously affects a decrease in water permeability. The gapping voids can be formed from 8 years and very probably made in 12 years after installation. Compression of decomposed husk causes the formation of gapping voids. Reduction of trench widths, which is more probable in wet clayey soil, lightens the risk of gapping void formation.

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Efficiency of subsurface drainage in paddy fields depends on the permeability of soil above filler layer. The objective of present study is to clarify the variability of the percolation rate along subsurface drainage. In eight paddy fields, six of which are used for rice cultivation and the others used for upland crops, cylinders having a diameter of 27.8 to 29.0cm were inserted to 18cm deep at intervals between 1 and 5m along the subsurface drainage pipe. The percolation rate in stable state (5 minutes after the start) was evaluated from the measurement of dropping water level in the cylinders. The percolation rate varied considerably with the location in the fields, and spatial correlation was also revealed. The influential ranges were estimated between 2 and 12m depending on the experimental plots. The percolation rate decreased as the filler depth increased when the filler depth was less than 20cm. The influential ranges of the filler depth were estimated between 4 and 10m, which had good correspondences with those of percolation rate. However in the fields where the measured filler depths exceed 20cm, no correlation was observed between the percolation rate and the filler depth. The observations of the crack depths around the location for the measurement revealed that the balance between the crack depth and filler depth determined the accessibility of surface water to the filler layer.

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A distributed water quality tank model was developed for the evaluation of the amount of the nitrogen removal by topographic sequence in the A10 basin, where the load from livestock farms is large, within Kitaura basin, the Kasumigaura watershed, Japan. A field investigation was conducted to collect the data for land use, water quality, and runoff. The study area was divided into a 50 m×50 m grid, and elevation, land use, and drainage were set as the grids attributes. A distributed water quality tank model was comprised of grid based water quality tank sub-model. After calibration, although the relative errors were large when there was no rain during the evaluation period, the relative errors were 9% for runoff and 2% for T-N concentration during the simulation period. For the purpose of a nitrogen removal by the appropriate allocation of artificial wetlands, a trial calculation for T-N concentration and nitrogen load removal was conducted given changes in the location of the artificial wetlands. As a result, T-N concentration was decreased by 4% in the case of valley head allocation for wetlands and by 18% when wetlands were allocated where the number of cumulative grids for water to pass was largest.

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Recently, livestock grazing using electric fencing is attracting attention as one form of land use and extensive management of abandoned paddy fields. We studied paddy field grazing from the viewpoint of management of farmland resources, and examined the effects of paddy field grazing on land use. Management of farmland resources bypaddy field grazing has the advantage of combining the following three factors: acclimating the cattle to grazing, installing electric fencing, and adjusting the shape of the field. Because of this, the effect of paddy field grazing is increased interrelationship among these elements.
Examination showed that preservation of farmland resources by cattle grazing could include the following functions. 1) The expansion function of extensive land use. 2) The distinct separation function of land uses. 3) The adjustment function for small-scale abandoned fields. 4) The weeding management function of farm-related institutions, such as farm roads connected with field lots. 5) The management function of scenery and environment.
These functions are thought to represent the possibility of forming a new farming method and a new spatial system of land utilization. In order to spread the practice of farmland management by grazing, it is necessary to acclimate both cattle and livestock owners to the system of grazing and to collectively manage the paddy fields used for grazing; we point out that a farmland foundation suitable for grazing needs to be formed and maintained.

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Recently, some reports described that the population of fishes that inhabit in the water zone of paddy field areas has decreased because of disconnecting watercourse network by the farmland consolidation project. As one of the engineering technologies to reconnect watercourse network, development of small-scale fishways installed atoutlet of the paddy field has been conducted. In such case, it is necessary to consider swimming performance of smallfishes todetermine installation dimension. In this study, therefore, swimming ability of loach Misguruns anguillicaudatus and crucian carp Carassius sp. was evaluated by a pipeline equipment. The results obtained were as follows;1) Since to measure so-called “rush speed” and “cruising speed” was considerably difficult, the swimming ability wasexamined under three categorized swimming forms, i.e. ascending, non-ascending and descending, 2) Loaches with 5 cm standard body length, loaches with 7 cm standard body length and crucian carp with 4-6 cm standard body length widely carried out ascending migration against the 50 and 70 cm·s^-1 flow velocity, and 3) An obtained relational expression, the ratio of flow velocity to the standard body length of fish that ascend against flow with success ratio of 40%, were 15.5, 12.3, and 13.7 in the cases of Loaches with 5 cm standard body length, loaches with 7 cm standard body length and crucian carp with 4-6 cm standard body length respectively.

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At present, the pavement design method of the national routes' is shifting from the empirical method to the theoretical one with the performance regulation introduction by the internationalization of the design method. In the design specification published by the Japan Road Association (JRA), the failure criterion proposed by US-Asphalt Institute (AI) is recommended for the asphalt pavement design, and this specification shows some examples based on the fatigue failure analysis of asphalt mixture and the rutting analysis. However, these examples are shown for the heavy volume traffic only, and the applicability of the AI's criterion for the low volume traffic is not confirmed yet.
In this study, the analytical rutting results using the AI's criterion and another estimating method were compared, and in this comparison the I-2-IV traffic structures which designed by the TA method in the farm road specification were used. As the results, it was found that the Al's criterion was not applicable for the low volume traffic asphalt pavements like the farm roads, and the pavement structure might be excessively when the present design specification by JRA was applied to the III-IV traffic pavement.

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