Sapporo, Japan
Sapporo, Japan

Time filter

Source Type

Yamaguchi S.,Japan Civil Engineering Research Institute for Cold Region | Watanabe Y.,Kitami Institute of Technology | Sumitomo K.,Docon Co.
River Sedimentation - Proceedings of the 13th International Symposium on River Sedimentation, ISRS 2016 | Year: 2017

Movable bed experiments using a wide laboratory flume without influence of fixed side walls were carried out in this study. The purpose of this study is to observe the process of river channel plane formation caused by bank erosion along a watercourse in the experiments. The shape of a channel plane changes with bank erosion or formation of braided streams and sandbars in the channel. The stages through which a straight channel, initially built on an erodible bank, develops into a node and anti-node plane were observed in this experiment. © 2017 Taylor & Francis Group, London.

Watanabe Y.,Kitami Institute of Technology | Sumitomo K.,Docon Co. | Yamaguchi S.,Japan Civil Engineering Research Institute for Cold Region | Yokohama H.,Hokkaido Regional Development Bureau
River Sedimentation - Proceedings of the 13th International Symposium on River Sedimentation, ISRS 2016 | Year: 2017

The Japanese government conducts an artificial flood by dam discharge for the purpose of preservation of river environment at the Satsunai river from 2012. This research was conducted using numerical simulation (iRIC Nays2D4.2) for the purpose of understanding quantitatively the effect of the artificial flood to river channel disturbance. It was evaluated quantitatively that artificial flood is effective in maintenance of anabranches. Moreover, it was found quantitatively that the effect of mainstream alternation at bifurcations during a large flood which is expected by the maintenance of distributaries. © 2017 Taylor & Francis Group, London.

An optical coating structure includes a substrate, an anti-reflective coating layer, a base coating layer, an antibacterial coating layer, and a protective coating layer. The anti-reflective coating layer is disposed on the substrate. The anti-reflective coating layer covers the substrate. The base coating layer covers the anti-reflective coating layer. The antibacterial coating layer is disposed on the base coating layer, and the antibacterial coating layer is an interlayer. The protective coating layer covers the antibacterial coating layer. A super-hydrophobic coating layer or an anti-fingerprint coating layer may cover the protective coating layer.

Katagiri K.,Hokkaido University | Yabe K.,Sapporo City University | Nakamura F.,Hokkaido University | Sakurai Y.,Docon Co.
Limnology | Year: 2011

To identify the causes of the rapid expansion of the semi-emergent Phalaris arundinacea L. community in a nutrient-loaded river, we investigated the factors that determine the distribution of the Phalaris and other aquatic macrophyte communities and the shoot growth of P. arundinacea. The Phalaris community was distributed through areas with high organic nitrogen (Org-N), total phosphorus (T-P), PO4-P and suspended solids (SS) concentrations and low dissolved oxygen (DO). P. arundinacea shoots grow better in deep mud and high SS and T-P, all of which were strongly correlated with slower stream currents. Accordingly, although the concentration of total nitrogen constantly increased from 1985 to 1998, the determining nutrient for the expansion of the Phalaris community and P. arundinacea shoot growth stimulation was phosphorus rather than nitrogen. The Phalaris community increased rapidly between 1991 and 1996, when brief but prominent loadings of phosphorus were observed. We concluded that the Phalaris community was restricted due to phosphorus deficiency under nitrogen excess until 1991 and subsequently rapidly expanded over the channel due to the temporary excess phosphorus present during this period. Thereafter, the rapid expansion of the Phalaris community was maintained by the clogging effect of the floating mats formed by shoots and their remains of P. arundinacea, which results in slower currents. A slower current resulted in low DO, the sedimentation of degraded plant remains (high Org-N), and the adsorption of phosphorus by suspended matter (high SS and T-P). The anaerobic conditions caused by low oxygen and the accumulation of decomposable organic matter ensure the continuous development of the Phalaris community through the release of soluble phosphorus from the sediment. © 2010 The Japanese Society of Limnology.

To determine depth dependence of permeability in various geologic deposits, exponential models have often been proposed. However, spatial variability in hydraulic conductivity, K, rarely fits this trend in coarse alluvial aquifers, where complex stratigraphic sequences follow unique trends due to depositional and post-depositional processes. This paper analyzes K of alluvial-fan gravel deposits in several boreholes, and finds exponential decay in K with depth. Relatively undisturbed gravel cores obtained in the Toyohira River alluvial fan, Sapporo, Japan, are categorized by four levels of fine-sediment packing between gravel grains. Grain size is also analyzed in cores from two boreholes in the mid-fan and one in the fan-toe. Profiles of estimated conductivity, K̄, are constructed from profiles of core properties through a well-defined relation between slug-test results and core properties. Errors in K̄ are eliminated by a moving-average method, and regression analysis provides the decay exponents of K̄ with depth. Moving-average results show a similar decreasing trend in only the mid-fan above ∼30-m depth, and the decay exponent is estimated as ≈0.11 m-1, which is 10- to 1,000-fold that in consolidated rocks. A longitudinal cross section is also generated by using the profiles to establish hydrogeologic boundaries in the fan. © 2013 Springer-Verlag Berlin Heidelberg.

Yamada Y.,Rakuno Gakuen University | Yamada Y.,Docon Co. | Sasaki H.,Rakuno Gakuen University | Harauchi Y.,Docon Co.
Journal of Insect Conservation | Year: 2010

Forest-dwelling carabid beetles that have no flight ability were studied using mark-recapture methods in late-June to mid-October 2007. This study was done to determine the effects of narrow roads in Nopporo Forest Park, Hokkaido on carabid beetle movement and habitat use. The investigation was conducted at four sites: one site was an abandoned grassy road with a width of 3.5 m, two sites were gravel roads with widths of 3.5 and 4.5 m, and another site was an asphalt-paved road with a width of 4.5 m. A total of 3,580 individuals from six species of carabid beetles were collected using dry pit-fall traps, and recapture rates ranged from 6.1 to 36.2%. All examined roads acted as barriers against the movement of Leptocarabus arboreus ishikarinus. All roads, except the abandoned grassy road, acted as a barrier against Carabus granulatus yezoensis movement. Forest-roadside verge comparisons demonstrated that some carabid beetles avoid even narrow roadside verges. Harmful effects increase with increasing road width and both paved roads and narrow roads negatively affect the movement of carabid beetles inhabiting the bordering forest. Therefore, forest specialist beetles are influenced by a barrier effect that starts at the forest road verge, and this barrier effect may be exacerbated by vehicular traffic. Therefore, these barrier effects on carabid beetles should be considered when planning and implementing road construction and maintenance in forests. © 2009 Springer Science+Business Media B.V.

Otani N.,Tokyo City University | Sugiki N.,Docon Co. | Miyamoto K.,Tokyo City University
Transportation Research Record | Year: 2011

Microsimulation models of land use characterize attributes of a household and its location, referred to as microdata in this study. However, methods for evaluating the goodness of fit between estimated and observed sets of agent-based microdata have not been investigated extensively. Although the attributes of a household include various items, such as the relationship with the household head and ages of the members, housing type and spatial location, number of cars owned, and income, the attributes can be classified into general categories. The objective of the present study is to develop a goodness-of-fit evaluation method for agent-based household microdata sets composed of generalized attributes. First, a distance measure between the estimated and observed microdata for each household is defined. In this definition a generalized scheme is introduced, whereby attributes are structured by the household composition, attributes of the member, and attributes of the household as a whole. The goodness of fit is measured on the basis of the minimum sum of distances for all households in the study area. The calculation cannot be carried out with just a conventional algorithm for microdata of a typical size because the number of calculations increases in proportion to the factorial (N!) of the number (N) of agents. Therefore, a genetic algorithm, especially one using symbiotic evolution, is developed to solve the problem. The effectiveness of the method in regard to accuracy and calculation feasibility is confirmed by using person trip survey data for the Sapporo metropolitan area in Japan.

Sakata Y.,Hokkaido University | Sakata Y.,Docon Co.
Groundwater | Year: 2015

Depth dependence of permeability can appear in any geologic setting; however, vertical trends in alluvial gravel deposits are poorly understood because of the high variability of hydraulic conductivity K in monotonic sequences. This paper examines the sensitivity of depth-decaying permeability through heat transport simulation around a river's losing reach in the Toyohira River alluvial fan, Japan. Observed variations in groundwater temperature indicate that heat fluxes are dominant in the shallow zone, despite a vertical hydraulic gradient. In eight cases with different conditions (presence or absence of exponential decay trend, large or small variogram range, and cell isotropy or anisotropy) 1000 K realizations are stochastically generated throughout a cross-sectional model. The groundwater flow and heat transport are transiently calculated, and the averaged root mean square error RMSE is used for sensitivity comparison. The variance of RMSE shows that small RMSE realizations are effectively reproduced with vertical trend assumed. Plausible realizations of RMSE below a given threshold were obtained only when a vertical trend was assumed. The most plausible realization almost completely matched the observations. However, the number of plausible realizations per case was ≤10 and the median RMSE were insensitive to all the conditions. Statistical testing suggested that these plausible realizations may be statistically significant, aiding in generating a connected K zone for high heat flows. The cell anisotropy condition had the smallest effect on the simulation. Thus, effective modeling of the vertical trend contributes to heat transport; however, the model's efficiency is low without detailed information about the sedimentary structure. © 2014, National Ground Water Association.

Uchida K.,Hokkaido University | Sugiki N.,Docon Co.
Journal of Advanced Transportation | Year: 2013

SUMMARY The Hokkaido Shinkansen (HS) bullet train line is under consideration to open in 2020. In this study, travel demand is estimated for the HS. Because some explanatory variables that are used for such estimation can have estimation errors, travel demand estimation risk is also calculated. In addition, because the HS can compete with airlines for modal share, the impacts of travel price competition (TPC) on the travel demand and the demand estimation risk are also estimated. In this study, the travel demand estimation risk is measured as the variance or the SD of the stochastic travel demand. The analysis reveals the following: the modal share of HS is 16% less when TPC is considered than when it is not considered; TPC causes the travel demand estimation risk to decrease; the probabilities of the HS operating at a deficit with and without consideration of TPC are calculated as 31.2% and 1.25%, respectively, and the increase in the mean consumer surplus accruing from the HS is calculated as JPY 47bn/year ($US588m/year) without TPC and as JPY 66bn/year ($US825m/year) with TPC. Copyright © 2012 John Wiley & Sons, Ltd. Copyright © 2012 John Wiley & Sons, Ltd.

D.O.N Co. | Date: 2016-07-12

Down jackets; down suits; button down shirts; underwear; footwear.

Loading Docon Co. collaborators
Loading Docon Co. collaborators