Evaluation of Infiltration Capacity and Water Retention Potential of Amended Soil Using Bamboo Charcoal and Humus for Urban Flood Prevention

In Japan, floods occur frequently in urban areas because non-infiltrating areas are seeing increased urbanization. To prevent floods, urban basins must improve the infiltration capacity and water retention of the whole basin. There are several basic technologies for river basin management, such as infiltration trenches or rainwater storage. However, a method of soil amendment that prevents flood disasters has not been established. This study aims to evaluate the infiltration capacity of soil amendments using bamboo charcoal and humus. A constant-head infiltration test and rainfall simulation were conducted to evaluate the properties of the soil amendments. The constant-head infiltration test＇s results showed that soils mixed with 30% humus had the greatest potential for influencing initial and final infiltration rates, and the more the mixing rates of bamboo charcoal and humus were increased, the higher the water retention capacity. The results of the rainfall simulation showed that soils mixed with 30% humus had the highest final infiltration rates and lowest multiplication spillage. To reduce the runoff volume using soil amendment technology, it is important to delay overland flow, and the hydraulic properties of the soils mixed with bamboo charcoal and humus were as effective as those of granite soils.

Numerical Simulation of Residual Circulation due to Bottom Roughness Variability Under Tidal Flows in A Semi-Enclosed Bay

Nowadays there are some chronic serious environmental problems, such as eutrophication, blue tide and so on, in a complicated coastal zone or a semi-enclosed bay, because the water exchanges between an inner bay and an outer sea is weak compared with the supply of contaminant. Under this situation, a method to improve the water quality by 3-dimensional small unsymmetrical structures has been proposed by Komatsu et al. In this paper, several numerical simulations of the tidal current and concentration for various arrangements of bottom roughness in a semi-enclosed model bay are carfled out with a depth-averaged 2-D numerical model. The model is solved by the hybrid finite analytic method with nonstaggered grid. And the SIMPLES algorithm with Rhie and Chow＇ s momentum interpolation technique is used for the simulation. The effect of Komatsu＇ s method for water purification is examined by numerical simulation. The result of numerical experiment indicates that it is possible to generate a new tidal residual current and to activate a tidal exchange by bottom roughness arrangement only.

Effect of Intertidal Elevation at Tsuyazaki Cove,Fukuoka,Japan on Survival Rate of Horseshoe Crab Tachypleus tridentatus Eggs

Physical factors affecting the survival of Tachypleus tridentatus eggs were investigated by translocating their eggs between the high intertidal zone and the low intertidal zone of a known spawning site.The mean egg survival rates per day were highest in the mid intertidal zone(45.1%±25.4%)and the lowest in the low intertidal zone(13.3%±27.6%).Differences in the elevation,air exposure time,and water content of the spawning ground were significant factors determining the egg survival rates.Excessive or insufficient air exposure time resulted in inadequate water content at higher and lower intertidal zones and could reduce egg survival.On the other hand,moderate saturation and dehydration were repeated with each tidal movement in the mid intertidal zone.This dynamic is considered as one of the crucial factors for the survival of eggs and is considered optimal for spawning.Therefore,the protection of the mid intertidal zone is imperative for maximizing the egg survival rate in Tsuyazaki Cove where almost all suitable nesting sites have disappeared due to coastal development.By protecting these optimal sites for spawning and recovering other optimal sites on suitable beaches,a positive contribution can be made to future management and conservation.The study also suggests that translocating eggs from marginal to optimal spawning sites might be a recovery strategy for this globally endangered species.

Microhabitat Use and Population Structure of a Chinese Kissing Loach, <i>Leptobotia tchangi</i>, in the North Tiaoxi River, China

Fundamental ecological information on the Chinese kissing loach (Leptobotia tchangi) was collected in the North Tiaoxi River, China, in September 2010. The length-frequency distribution calculated using FiSAT software showed the population structure of this kissing loach could be classified into four age groups suggesting that the life span of the loach should be 3 - 4 years. A stepwise multiple linear regression analysis revealed that the density of this kissing loach was significantly and positively correlated with water velocity, while the body size was significantly and positively correlated with river bed pebble size. It suggested that water velocity and variation of pebble size play important roles in the full life history of this kissing loach. Thus, maintenance of the rapid current and variety of substrate are essential for the conservation of this species under the present conditions in the river, which also can support river restoration being in harmony with survival of this kissing loach.

Impact Analysis of Bridging on Remote Island Population

We analyzed the determinants of building bridges after comparing bridge islands and non-bridge islands.In addition,we examined the population change before and after the bridge building and the factors influencing the change.As a result,a remote island with high cost-effectiveness was selected and bridged.The early bridge was built in remote islands with fragile social infrastructure,and the outflow of population was suppressed owing to the improvement in standard of living by securing the medical care and education available in the bridge destination.However,around the year 2000,there are few remote islands where the changes in populations are influenced after a bridge was built.

Influence of Stand-Alone Vertical Gas Vents on Aeration and Denitrification of Organic Municipal Waste Assessed by Two-Dimensional (2D) Lysimeters

Landfilled organic waste, in the presence of oxygen, can undergo aerobic decomposition facilitated by heterotrophic microorganisms. Aerobic degradation of solid waste can quickly consume available oxygen thus curtailing further degradation. The aim of this study was the investigation of a low-cost method of replenishing oxygen consumed in landfilled waste. Three 2D lysimeters were established to investigate the effectiveness of stand-alone, vertical ventilation pipes inserted into waste masses. Two different configurations of ventilation were tested with the third lysimeter acting as an unventilated control. Lysimeters were left uninsulated and observed over the course of 6 months with regular collection of gas and leachate samples. Lysimeters were then simulated for Oxygen (O2) and Nitrous oxide (N2O) to analyze the denitrification contributions of each. The experiment revealed that a single ventilation pipe can increase the mean oxygen level of a 1.7 m × 1.0 m area by up to 13.5%. It also identified that while increasing the density of ventilation pipes led to increased O2 levels, this increase was not significant at the 0.05 probability level. A single vent averaged 13.67% O2 while inclusion of an additional vent in the same area only increased the average to 14.59%, a 6.7% increase. Simulation helped to verify that lower ventilation pipe placement density may be more efficient as in addition to the effect on oxygenation, denitrification efficiency may increase. Simulations of N2O production estimated between 8% - 20% more N2O being generated with lower venting density configurations.

Feasibility of Natural Zeolite for Heavy Metal Stabilization in Municipal Solid Waste Incineration Fly Ash: A Novel Approach

The current study investigated the sorption process of heavy metals, especially lead (Pb2+) and Zinc (Zn2+), in Municipal Solid Waste Incineration (MSWI) fly ash applying natural zeolite, namely mordenite, as an inexpensive adsorbent to assess its feasibility for the treatment of fly ash. Batch experiments were performed to investigate the effects of the influential parameters, such as metals initial ion concentration, dosage of adsorbent, liquid to solid (L/S) ratio, and equilibrium concentration of metal on the immobilization of Pb2+ and Zn2+, in a novel approach. Heavy metals removal efficiency increased with increasing the dosage of mordenite influenced by the media-specific surface area. Heavy metals adsorption is ascribed to various mechanisms of ion exchange and adsorption processes. The Langmuir and Freundlich isotherm models were investigated using the adsorption data. The adsorption process describes better in the Freundlich isotherm model compared to the Langmuir isotherm model with a high determination co-efficient (R2), especially for the adsorption of Pb2+. In addition, the affinity of mordenite to Pb2+ was shown to be higher than that of Zn2+. This allows the use of mordenite to capture of Pb2+ in MSWI fly ash. Results raise expectations about using mordenite as a low-cost material for treating MSWI fly ashes. The results show that heavy metal (Pb2+ and Zn2+) removed by mordenite adsorbent is practical and effective. In order to achieve the higher efficiency on heavy metal stabilization in MSWI fly ash, additional experiments are necessary.

Simulation and Calibration of Hydro-Debris 2D Model （HD2DM） to Predict the Particle Segregation Processes in Debris Flow

The principal aim of a vertical two-dimensional numerical model development is for estimating the particle tracing and mechanism of 10 mm and 2.5 mm debris. The particle tracing movement can be visually analyzed by using a high speed video camera （HSVC）. A numerical model was developed using the Marker and Cell Method, which involves a Subgrid-Scale （SGS） model and the Particle Source in Cell （PSI-Cell） Method. The transportation processes of debris and air bubble were simulated in lagrangian form by introducing air bubbles and debris markers. Air bubble movement characteristics were simulated by this numerical model. Bigger particles flow at the upper part, while smaller particles attach near to the bottom. This phenomenon is similar to what we observed in the experimental studies. As a conclusion, the calibration processes for velocity was successful. The value of virtual mass （CM） was found to be one of the most important criteria that should be considered in the calibration process, as this parameter dominates fundamental characteristics of sediment particle movement in the lagrangian numerical scheme. The best fitted CM in this study was 0.35. The mean average velocity value ranging from 1.2% to 22.61% is obtained from the velocity results of numerical studies compared to the experimental studies.

Hard-to-Soft Transition in Radial Buckling of Multi-Concentric Nanocylinders

We investigate the cross-sectional buckling of multi-concentric tubular nanomaterials, which are called multiwalled carbon nanotubes (MWNTs), using an analysis based on thin-shell theory. MWNTs under hydrostatic pressure experience radial buckling. As a result of this, different buckling modes are obtained depending on the inter-tube separation d as well as the number of constituent tubes N and the innermost tube diameter. All of the buckling modes are classified into two deformation phases. In the first phase, which corresponds to an elliptic deformation, the radial stiffness increases rapidly with increasing N. In contrast, the second phase yields wavy, corrugated structures along the circumference for which the radial stiffness declines with increasing N. The hard-to-soft phase transition in radial buckling is a direct consequence of the core-shell structure of MWNTs. Special attention is devoted to how the variation in d affects the critical tube number Nc, which separates the two deformation phases observed in N -walled nanotubes, i.e., the elliptic phase for N Nc. We demonstrate that a larger d tends to result in a smaller Nc, which is attributed to the primary role of the interatomic forces between concentric tubes in the hard-to-soft transition during the radial buckling of MWNTs.

Tank模型及其在边坡水位预测中的应用(英文)

Tank模型可以模拟非线性的降雨–地下水运移过程,并且能迅速得到解答。基于现有的单列tank模型,提出新的复合水箱模型。由于新模型参数超过20个,应用传统优化算法难以快速找到最优解,一种新的启发式自搜索算法(变维数搜索算法)被引入并改进后用于模型最优解的寻找。变维数搜索算法能够根据搜索进程的变化自动改变搜索维数并且快速找到最优解。27个参数的复合tank模型被应用于日本国道九号线的一个边坡,计算结果表明:变维数搜索算法能够在10 min左右找到合适的最优解;降雨过程复合tank模型计算的地下水位变化和观测值非常接近。最后通过和有限单元法计算结果的比较表明,有限单元法的计算结果受地质渗透特性的影响很大,而复合tank模型不存在这种问题。工程实例计算表明,该方法和监测结果比较一致,但其适应性更强,特别适用于没有进行足够地质结构探查的边坡。它能够快速反映降雨过程中地下水位的运移过程,可以推广使用。

Hurst’s Memory for Chaotic, Tree Ring, and SOI Series

Hurst’s memory that roots in early work of the British hydrologist H.E. Hurst remains an open problem in stochastic hydrology. Today, the Hurst analysis is widely used for the hydrological studies for the memory and characteristics of time series and many methodologies have been developed for the analysis. So, there are many different techniques for the estimation of the Hurst exponent (H). However, the techniques can produce different characteristics for the persistence of a time series each other. This study uses several techniques such as adjusted range, rescaled range (RR) analysis, modified rescaled range (MRR) analysis, 1/f power spectral density analysis, Maximum Likelihood Estimation (MLE), detrended fluctuations analysis (DFA), and aggregated variance time (AVT) method for the Hurst exponent estimation. The generated time series from chaos and stochastic systems are analyzed for the comparative study of the techniques. Then, this study discusses the advantages and disadvantages of the techniques and also the limitations of them. We found that DFA is the most appropriate technique for the Hurst exponent estimation for both the short term memory and long term memory. We analyze the SOI (Southern Oscillations Index) and 6 tree-ring series for USA sites by means of DFA and the BDS statistic is used for nonlinearity test of the series. From the results, we found that SOI series is nonlinear time series which has a long term memory of H = 0.92. Contrary to earlier work, all the tree ring series are not random from our analysis. A certain tree ring series show a long term memory of H = 0.97 and nonlinear property. Therefore, we can say that the SOI series has the properties of long memory and nonlinearity and tree ring series could also show long memory and non-linearity.

The ＂MIZBERING＂ Zuibaiji Conference - A Search for Continuity in the Zuibaiji River Basin-

The Zuibaiji River is located in the west of Fukuoka city, which has a rich natural resources and history but various problems as well. In order to solve some of these problems, stakeholders need to observe and talk about the river. Also recently, the ＂MIZBERING Project＂ has been opening up possibilities for renewing riverside uses of lost activities from the old days in Japan. This project is being conducted by citizens, companies and government administrations with an interest in waterside areas. The First MIZBER1NG Zuibaiji River Conference was held to discuss the issues of the Zuibaiji Basin. Its purpose was to visit and search out the nature and history of the entire Zuibaiji Basin from its mountains to the sea and to rediscover the Zuibaiji Basin, and finally to discuss future plans for the Zuibaiji Basin and Imazu Tidal Flat at its outlet. After visiting the Zuibaiji Basin, we discovered a problem that the Zubaiji Dam is holding not only water but also sand, and this problem affects the environment of the Zuibaiji Basin, such as its ecosystem and topography. Finally, we provided a venue for the local people to discuss problems and future plans for the Zuibaiji Basin.

Vietnam’s Future Water Usage Model: A Controlled Living Experiment

The purpose of this study was to explore the water usage profile of future Vietnamese households by carrying out a controlled living experiment with Vietnamese high-income households. By studying showering time, flow rate and toilet-use frequency of these households, the study revealed the water usage believed to be representative of future households in light of continued urbanization. This study also determined that the average time of showering was 9.7 minutes per person per day with an average flow rate of 12 L/minute for the existing shower head and 6.6 L/minute for the water-saving shower head. Toilet usage frequency was 5.25 times per person per day, and there was no difference with the results for an average (middle-income) household.

利用卫星反演降雨量评估流域尺度浅层滑坡预测系统的分布式水文-岩土工程模型

本文描述了利用基于卫星降雨量评估浅层滑坡预报系统的水文．岩土工程建模系统的潜在适用性。通过集成一个利用无限斜坡稳定性方法和基于网格分布式运动波降雨径流模型，基于物理的分布式模型得到开发。该模型被用于NOAA．CPC提供的基于卫星的近实时半小时CMORPH全球降雨量。该方法结合了以下两种模型输出，从而确定浅层滑坡在流域何时何地发生：（1）边坡易失稳地区非时变的空间分布，根据临界相对土壤饱和度，把这些地区划分成不同稳定类型。这种输出用来描绘准静态陆地表面变量和土壤强度性能对边坡失稳的影响；（2）与空间和时间变化的水文特性相联系的地图提供了一个随时间变化且响应降雨的斜坡活动敏感性评估。水文模型预测每个网格单元的土壤饱和动态。随后，每个网格单元中的储存水用于更新土壤相对饱和度和分析边坡稳定性。当土壤相对饱和度高于临界水平，斜坡网格被认为是不稳定，这也是发出浅层滑坡预警的基础。该方法适用于过去印度尼西亚Citarum流域上游（2，310平方千米）的山体滑坡；非时变滑坡敏感性图说明该方法与记录的历史滑坡（1985．2008年）的空间类型有很好一致性。在最近2个浅层滑坡中的应用表明，该模型可以成功地预测降雨活动和强度对触发浅层滑坡水文变量时空动态的影响。山体滑坡的几个小时前，该模型可以预测在浅层滑坡实际发生的网格和其附近的不稳定条件。总的来说，结果表明建模系统对浅层滑坡灾害预测和预警具有潜在适用性。

Use of probabilistic and deterministic measures to identify unfavorable earthquake records

This study introduces measures to identify resonant (concentration of energy in a single or a few frequencies) or unfavorable earthquake ground motions. Probabilistic measures based on the entropy rate and the geometric properties of the power spectral density function (PSDF) of the ground acceleration are developed first. Subsequently, deterministic measures for the frequency content of the ground acceleration are also developed. These measures are then used for identifying resonance and criticality in stochastic earthquake models and 110 acceleration records measured at rock, stiff, medium and soft soil sites. The unfavorable earthquake record for a given structure is defined as the record having a narrow frequency content and dominant frequency close to the structure fundamental natural frequency. Accordingly, the measures developed in this study may provide a basis for selecting records that are capable of producing the highest structural response. Numerical verifications are provided on damage caused to structures by identified resonant records.

Characterization of chlorine and heavy metals for the potential recycling of bottom ash from municipal solid waste incinerators as cement additives

Bottom ash is an inevitable by-product fi＇om municipal solid waste （MSW） incineration plants. Recycling it as additives for cement production is a promising disposal method. However, the heavy metals and chlorine are the main limiting factors because of the potential environmental risks and corrosion of cement kilns. Therefore ,investigating heavy metal and chlorine characteristics of bottom ash is the significant prerequisite of its reuse in cement industries. In this study, a correlative analysis was conducted to evaluate the effect of the MSW components and collection mode on the heavy metal and chlorine characteristics in bottom ash. The chemical speciation of insoluble chlorine was also investigated by synchrotron X-ray diffraction analysis. The results showed that industrial waste was the main source of heavy metals, especially Cr and Pb, in bottom ash. The higher contents of plastics and kitchen waste lead to the higher chlorine level （0.6 wt.%-0.7 wt.%） of the bottom ash. The insoluble chlorine in the MSW incineration bottom ash existed primarily as AlOCl, which was produced under the high temperature （1250℃） in incinerators.

Property of critical excitation for moment-resisting frames subjected to horizontal and vertical simultaneous ground motions

It has often been reported that, when building structures are subjected to near-fault earthquake ground motions, horizontal and vertical impulsive inputs may cause critical damage during the first few seconds. In practical design of building structures, however, the safety check, taking into account the effect of multi-component ground motions, is hardly conducted except the design of important structures such as high-rise buildings and nuclear power plants. Ftirthel＇more, it is not clear how the correlation of multi-component ground motions influences the actual safety of structures. In this paper, the detailed property of critical excitation is discussed in association with the relationship between the characteristics of ground motions and those of structures. The properties of various auto power spectral density （PSD） functions of the horizontal and vertical ground motions are investigated, and those of the critical cross PSD function of these two-directional ground motions are found by a devised algorithm in a feasible complex plane. A closed-form expression is derived from the critical relation of the auto PSD functions of the simultaneous inputs. This critical excitation method provides us with a new approach for earthquake-resistant design against the possible future earthquake which causes the critical damages to buildings.

Temporal variation in modal properties of a base-isolated building during an earthquake

Temporal variation of dynamical modal properties of a base-isolated building is investigated using earthquake records in the building. A batch processing least-squares estimation method is applied to segment-wise time-series data. To construct an input-output system,an auto-regressive model with exogenous input (ARX) of second-order including a forgetting coefficient as a weighting coefficient is used for the estimation of modal parameters. The fundamental and second natural frequencies and the damping ratios of the fundamental and second natural modes of the base-isolated building are identified in the time domain. The identified results are consistent with the results obtained from the micro-tremor vibration data,forced-vibration test data and earthquake records in the present base-isolated building in the case of taking into account the amplitude-dependency of the isolators and viscous dampers. It is finally pointed out that several factors,e.g.,amplitude dependency of the isolator and damper system and special characteristics of the series-type viscous damper system,may be related complicatedly with the temporal variation in modal properties of the above-mentioned system.

Lessons learned from the Ezgeleh-Sarpol Zahab earthquake of November 2017:status of damage and disposal of disaster waste

A massive earthquake of magnitude Mw 7.3 shook Kermanshah Province in Western Iran along the Iraqi border on November 12,2017.The epicenter of the earthquake was approximately 10 km southwest of Ezgeleh Town in Kermanshah Province.Field observations almost 4 months after the disaster indicated that the earthquake had caused tremendous damage to most structures in both urban and rural areas,and left an enormous amount of disaster waste.To investigate the status of the dam-age and disposal of the disaster waste,remote sensing was conducted using an unmanned aerial vehicle(drone).Through the capture of low-altitude images by drone and the generation of 3D models,the quantity of debris accumulated in a waste disposal facility near Sarpol Zahab was estimated at approximately 480,000 m3.A compositional analysis of the disaster waste was performed using an imaging technique.This revealed that the disaster waste was largely composed of concrete(39.6%),hollow brick(35.4%),and gypsum(21.2%)in the urban area,whereas soil was the dominant component(77.4%)in the rural area.The damage caused to most buildings was essentially due to their non-standard construction.The manage-ment of debris from the damaged buildings was a critical issue for the authorities,and the lack of preparedness was a serious drawback that consumed an enormous amount of time,budget,and workforce.A practical post-disaster preparedness plan would help the decision-makers and the public to manage the otherwise overwhelming nature of the post-disaster conditions in a more reasonable manner.