Articles

  1. FLOOD HAZARD MAPPING USING ON-SITE SURVEYED FLOOD MAP, HECRAS V.5 AND GIS TOOL: A CASE STUDY OF NAKHON RATCHASIMA MUNICIPALITY, THAILAND Download Article

    Haruetai Maskong, Chatchai Jothityangkoon and Chow Hirunteeyakul
    • Article Type: Research Article
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    • Pages (1-8)
    • No of Download = 458

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    For a small flood affected area, satellite data normally provides physical properties of flood
    event with low accuracy information (location and boundary). Flood depth and flood duration cannot be
    identified from a snapshot of satellite image. Therefore, on-site surveying of historical flood properties and its
    impact are still essential, and this observed flood map is realistic and reliable information for future flood
    management. The objective of this study is to construct a flood hazard map from available observed flood map
    of the small flood affected area and use HEC-RAS V. 5 and GIS tool to formulate the flood hazard map for future scenarios. This method was applied for the municipality of Nakhon Ratchasima, Thailand. For a simulation, input physical parameters were generated by Hec-GeoRAS in ArcGIS based on DEM (5×5 m2). A range of calibrated Manning’s n in a main channel was obtained from fitting exercise with observed Rating curve. Land-use map was used to estimate the Manning’s n in floodplain depending upon the type of land cover. Simulated results were exported to ArcGIS to delineate water surface on floodplain. Then, the maximum discharge value at the observed station (M. 164) for return periods of 5, 10, 15, 25, 50, and 100 years were used as upstream input flood to simulate the flood map. It is found that, for the 2010 flooding event in the concerning area, the simulated flood hazard map subjected to the discharge of 50 years return period (217 m3/s) which is almost identical with the observed flood map from the surveying.

  2. ENVIRONMENTAL REGENERATION AND MANAGEMENT IN PARTNERSHIP IN THE NORTHWEST OF ENGLAND Download Article

    Tomoko Miyagawa, Clare Olver, Noriko Otsuka and Hirokazu Abe
    • Article Type: Research Article
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    • Pages (9-15)
    • No of Download = 412

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    Built environment and cultural heritage are important aspects to improve the quality of life in
    environmental regeneration and management. This paper aims to compare two case studies to examine
    partnership for environmental regeneration and management in post-industrial landscapes in the northwest of England: conservation and interpretation of the salt heritage at Northwich Woodlands, and landscaping former coalfields with artworks at Bold Forest Park, St.Helens. Study methods used are literature reviews and faceto-face interviews with representatives from partnership organisations, e.g. Mersey Forest, local authority officers, and Friends of Anderton and Marbury. From the results, characteristics of the two projects became apparent with distinctive focuses: industrial heritage in Northwich Woodlands; and creating a focal point using collaborative artworks in St. Helens. Similarities are also found in outcomes of environmental regeneration to create wildlife areas with some statutory designations, and partnership patterns integrating sectors from public, private, and the community. For both case studies, the overriding issue is being able to develop the resources and partnerships to enable the sites to be managed and thus cherished by their communities in the long term.

  3. REGENERATION FOR SOCIO ECOLOGICAL PRODUCTION LANDSCAPE IN SERIOUSLY ENVIRONMENTAL DAMAGEDRURAL AREA Download Article

    Takato Azegami, Hirokazu Abe, Noriko Otsuka and Tomoko Miyagawa
    • Article Type: Research Article
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    • Pages (16-22)
    • No of Download = 385

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    This research aims to explore the regeneration for socio ecological production landscape in seriously environmental damaged rural area through the field survey of prior efforts around the area. In Fukushima, six years have passed since the nuclear accident, and evacuation orders for about 32,000 people living in Namie, Iitate, Tomioka and Yamakiya District of Kawamata, have been lifted by April 2017. However, since the socio ecological production landscape has lost, the lifting of this evacuation order will not lead directly to the return home of residents. The challenge is how to restore people’s former life which was based on agriculture and forestry and this research looks into the ways of regenerating the socio ecological production landscape, using interview with local community representatives and field observation. The case study has revealed that the decontamination of the forest is still in a trial stage and the key obstacle is the fact that there are still a few people who wish to return because the future concrete outlook is still not visible. However, a new community has been gradually generating by the approach which a part of farmers resume farming with external researchers and volunteers with interest. It seems to lead to the potential for regeneration of the socio-ecological production landscape.

  4. STUDY ON REMOVAL OF CONTAMINATED SOIL ON FOREST SLOPE FOCUSING ON DIFFERENCE IN DENSITY OF SUBSURFACE GROUND Download Article

    Keiichiro Shibata, Hidenori Yoshida, Daisuke Matsumori, Matsumoto Naomichi and Kazushi Moriki
    • Article Type: Research Article
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    • Pages (23-28)
    • No of Download = 369

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    A large amount of radioactive cesium was released from the Fukushima Daiichi nuclear power station. Decontamination in living area has been almost completed for seven years. However, decontamination has not progressed much in forests where people do not enter. The decontamination of soil on forest slope cannot be done using heavy machinery unlike that on flatland. The effective decontamination method for the forest slope is desired. Therefore, in this study, the collecting method of slope surface soil through flushing water and the soil separation method focusing on the difference in the density of minerals were proposed and examined. In the proposed method, it is expected to reduce the volume of contaminated soil through the separation of the contaminated part and non-contaminated one. In this study, the laboratory test is conducted to evaluate the usefulness of the proposed method. In the test, a device of simulating the slope and a device to flush the soil by flowing water is produced. When an actual soil is utilized for the experiment, it is difficult to ensure the experimental repeatability due to soil variability. Therefore, simulated soil consists of Toyoura standard sand and vermiculite. To simulate soil contaminated with cesium, cesium standard solution is added into the simulated soil. The soil is set on the slope, and the test is conducted to flush and collect the soil by running water from upside to downside. As a result, it is clarified that only soil containing cesium can be removed by separating the soil after flushing.

  5. FLUIDIZED BED COAL-BARK FLY ASH GEOPOLYMER WITH ADDITIVES CURED AT AMBIENT TEMPERATURE Download Article

    Prinya Chindaprasirt, Pornnapa Kasemsiri, Suttipong Poomsrisa-ard and Patcharapol Posi
    • Article Type: Research Article
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    • Pages (29-35)
    • No of Download = 258

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    In this research, the properties of fluidized bed coal-bark fly ash geopolymer mortar containing additives viz., ordinary Portland Cement (OPC) and micro silica (MS) were studied. The fluidized bed coal-bark fly ash was a waste from a power plant boiler in Khon Kaen, Thailand. The geopolymer mortar was made from fluidized bed coal-bark fly ash, sand, sodium silicate solution, NaOH solution, and additives. The additives were used to replace the fluidized bed coal-bark fly ash at the level of 0 - 15 % by weight. The mortars with liquid alkaline/ash ratios of 0.9-1.4, sodium silicate/NaOH ratios of 0.33-3.00, NaOH concentrations of 5-15 molars, OPC and micro silica contents of 0 - 15 % by weight of fly ash, and curing at ambient temperature were tested. The geopolymer mortars with 28-day compressive strengths between 5.5 and 27.0 MPa and densities between 1970 and 2175 kg/m3 were obtained. The addition of OPC and micro silica enhanced the strength development of geopolymer mortar with the optimum OPC content of 10 % and micro silica content of 15 %. It is shown here that the fluidized bed coal-bark fly ash geopolymer mortar containing OPC and micro silica as additives with ambient temperature curing possesses sufficient strength. The use of this product can reduce the energy consumption in cement production and increases the sustainability of construction industry.

  6. EFFECT OF FLY ASH FINENESS ON COMPRESSIVE, FLEXURAL AND SHEAR STRENGTHS OF HIGH STRENGTH-HIGH VOLUME FLY ASH JOINTING MORTAR Download Article

    Patcharapol Posi, Pornnapa Kasemsiri, Surasit Lertnimoolchai and Prinya Chindaprasirt
    • Article Type: Research Article
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    • Pages (36-41)
    • No of Download = 263

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    In this research, the compressive, flexural, and shear bond strengths of high strength-high volume fly ash mortar containing high calcium fly ash (HCFA) of various finenesses were studied. The mortars were made from ordinary Portland cement (OPC), HCFA, sand, water, and Type D admixture. The HCFA was from Mae Moh power station in the north of Thailand. Three types of HCFA fineness viz., as-received coarse fly ash (CF), medium fineness fly ash (MF, passed sieved No. 100), and fine fly ash (FF, passed sieve No. 200) were used to replace OPC at the levels of 0-70 % by weight of binder. The results showed that the high strength-high volume fly ash mortars with satisfactory 28-day compressive strengths between 70.0 and 114.0 MPa, shear bond strengths between 7.2 and 18.0 MPa, and flexural strengths between 15.9 and 27.6 MPa were obtained. Test results also indicated that the use of FF gave significantly higher strengths than the use of CF and MF. Specifically, the compressive strength of mortar containing 50%FF was very high at 110.0 MPa. The FF could thus be used to improve the strengths of high volume fly ash mortar for uses in various architectural and structural works requiring high strength products.

  7. STRENGTH AND BEHAVIORS OF DRY-JOINT RETAINIG NANO-BLOCK Download Article

    Poungchompu Pongsagorn, Buyarat Tanakrit and Bubpi Attaphol
    • Article Type: Research Article
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    • Pages (42-48)
    • No of Download = 342

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    This research studied the strength and behaviors of dry-joint retaining walls built with nano blocks, a new product made from wet-cast concrete of the size 20×40×18cm, with the weight of 15kg/block, and the compressive strength of 94kg/cm². Construction of retaining walls with these dry-joint nano blocks–both for permanent and temporary walls – is simple, convenient and fast without having to rely on skillful workers. The research started from producing a prototype scale model of 1:12.5 for determining appropriate experimentation. The structure of the retaining wall using 2.00×1.65×0.20meters dry-joint nano blocks allowed distribution of lateral earth pressure through the sand in a semicircular-cut cylindrical mold of 15cm radius and 1.60 meters height. Pressure was applied step by step all through the test. Gauging of both horizontal and vertical displacements was performed using a dial gauge. The testing program for the nano-block retaining wall comprised 5 patterns of walls: half-block, half-block with 1.38kg-m steel reinforcement, half-block with 2.77 kg-m steel reinforcement, half-block with 4.15kg-m steel reinforcement, and anchored half-block with1.38kg-m steel reinforcement. Horizontal displacement was checked stepwise.Comparison of the efficiency of the 5 patterns showed that the half-block nono-block retaining wall demonstrated the highest horizontal displacement the retaining wall yielding the highest efficiency was the anchored half-block with 1.38kg-m steel reinforcement, with the least horizontal displacement of 2.90mm. It can be concluded that steel reinforcement and structural anchoring increases stability of nano-block retaining walls in terms of lateral compressive strength.

  8. PURIFICATION EXPERIMENTS ON THE PASIG RIVER, PHILIPPINES USING A CIRCULATION-TYPE PURIFICATION SYSTEM Download Article

    Okamoto Kyoichi, Komoriya Tomoe, Toyama Takeshi, Hirano Hirosuke, Garcia Teodinis, Baccay Melito, Macasilhig Marjun, Fortaleza Benedicto
    • Article Type: Research Article
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    • Pages (49-54)
    • No of Download = 441

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    Polluted sludge from the Pasig River generally exerts a very large environmental load to the surrounding area near the vicinity of Laguna de Bay and Manila Bay in the Philippines. Historically, the river was used to be a good route for transportation and an important source of water for the old Spanish Manila. However, the river is now very polluted due to human negligence and industrial development, and biologists consider it unable to sustain aquatic life. Many researchers have conducted studies on the Pasig River, unfortunately, no considerable progress from the point of view of purification process have succeeded. Hence, in this study, the use of fine-bubble technology for the purification of the polluted sludge from the said river is being explored. The critical point in using this technique is on the activation of the bacteria existing in the area using fine bubbles. The sludge is decomposed and purified by activating the aerobic bacteria after creating an aerobic state. In this study, the main objective is to test the performance of the purification system on the sludge and water taken from the Pasig River by comparing the results with the case study conducted in Funabashi Port, Japan. Based on the results of the study, it was established that the use of a circulation-type purification system is very good for it significantly decreased the total nitrogen in the samples from the Pasig River and Funabashi Port. Generally, the said system is considered effective in treating and purifying ocean or river sludge.

  9. BOND STRENGTH PREDICTION MODEL OF CORRODED REINFORCEMENT IN CONCRETE USING NEURAL NETWORK Download Article

    Nolan C. Concha and Andres Winston C. Oreta
    • Article Type: Research Article
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    • Pages (55-61)
    • No of Download = 455

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    The expansion of corrosion products in the steel-concrete interface offers radial tensile stress resulting in the development of cracks in reinforced concrete structures. This corrosion-induced crack promotes bond reduction involving intricate non-linear interactions. To deeply understand the underlying mechanisms in the bond strength of corroded rebars in concrete, a novel bond prediction model using artificial neural network (ANN) was developed. Accelerated corrosion was performed to 108 cube samples using 500 μA/cm2 current density. Steel bond strength after 35 and 70 days impressed corrosion exposure of concrete cube samples was measured using a single pull out test. The compressive strength, tensile strength, rebar diameter, embedment length, concrete cover, ultrasonic pulse velocity (UPV), crack severity, and corrosion level were the predictors in the ANN bond model. Among all the bond strength models considered in this study, the proposed neural network model provided the most desirable bond estimates in good agreement with experimental results. The ANN model further showed superior prediction performance against the derived regression model.

  10. DAMAGE DETECTION OF TRUSS STRUCTURES BY APPLYING MACHINE LEARNING ALGORITHMS Download Article

    Koji Unno, Atsushi Mikami and Masaki Shimizu
    • Article Type: Research Article
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    • Pages (62-67)
    • No of Download = 426

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    Infrastructures including bridges constructed in the period of high economic growth are getting older. For the damage detection of truss structures, this study assumes to utilize vibration signals obtained from sensors installed into the bridges. By preparing damaged and non-damaged bridge structures, large quantities of response data are generated. AR (Auto-Regressive) model is then applied to the time signals to extract the structure’s soundness characteristics. Here, AR coefficients are values in which damaged structural characteristics are reflected. Then, the machine learning technique is applied to the AR coefficients to classify the structures into damaged and non-damaged ones. Results showed that the machine learning method successfully detected the damage of truss members. This kind of SHM (Structural Health Monitoring) technology is expected to contribute to early damage detection and preventive maintenance of bridges leading to increase the accuracy of the damage detection of truss structures with low costs and fewer efforts for maintenance.

  11. COMMUNITY EMPOWERMENT IN PLANTING VEGETATION TO REDUCE COASTAL ABRASION IN WEST SUMATRA Download Article

    Taufika Ophiyandri, Bambang Istijono and Abdul Hakam
    • Article Type: Research Article
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    • Pages (68-73)
    • No of Download = 388

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    The length of the West Sumatra Province coastline is 420 km. The coastal area has many settlements and as a source of natural attraction for tourism industry. However, due to the increase of hydro-meteorological disaster such as abrasion, there has been considerable damage to approximately 180 km of coastal length in recent years. This paper aims to identify the relationship between the types of vegetation that grow along the coast with the abrasion rate and to identify the role of the community for conservation of vegetation. The aim is achieved through literature review, observation, and interviews with government official and communities who live on the beach. Data processing is done by analyzing the relationship between abrasion rate and vegetation type, and by conducting content analysis on interview data. It was found that certain types of plants have the ability to cope with and reduce abrasion rates. Plant breeding and planting is recommended to be a part of non-structural mitigation efforts. Community empowerment in planting and maintaining vegetation provides excellent results for sustainability.

  12. THE EFFECT OF FLOOD TO QUALITY INDEX OF SOIL PHYSICAL PROPERTIES AT THE DOWNSTREAM OF KURANJI RIVER WATERSHED, PADANG CITY Download Article

    Aprisal, Bambang Istijono, Taufika Ophiyandri and Nurhamidah
    • Article Type: Research Article
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    • Pages (74-80)
    • No of Download = 344

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    The downstream of the Kuranji watershed of Padang City is vulnerable to flood due to the changes of land use into settlements area. Land use changes have changed the soil physical properties and its infiltration. The inundation has changed soil physical properties, such as layers, textures, volume weight, pores, permeability, and soil organic matters. The objective of this research is to analyze the quality index of soil physical properties due to flood at the watershed of the downstream area of Kuranji River of Padang City. Research methodology adopted is by conducting a field survey. Location of the soil sample is selected by purposive random sampling and was analyzed at the Department of Soil Science Andalas University. Soil physical properties data was arranged as minimum data sets (MDS) to be analyzed with principal component analysis to identify the main factors most affected by the flood. The results show that the main soil physical properties influenced by the flood are texture and soil organic matter. Based on the calculation of selected values from the MDS data, the quality of the downstream Kuranji watershed is moderate to good.

  13. SETTLEMENT OF SURROUNDING GROUNDS DUE TO EXISTENCE OF PILE PULLING-OUT HOLES Download Article

    Shuichi Kuwahara and Shinya Inazumi
    • Article Type: Research Article
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    • Pages (81-85)
    • No of Download = 334

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    The demolition of social infrastructures including the civil structures have been increasing because of aging them constructed during in a period of high economic growth and decrease in their utilization with a population decrease, in recent years. As a result, removal works of existing pile in the ground have been increasing. Pulling-out method is adopted for removal of existing a pile foundation in the present circumstances. However, after pulling-out a pipe foundation, decline of mechanical characteristic of surrounding ground is concerned by forming pulling-out holes. There are no regulations yet for filler injected into a pulling hole, and the influence of the strength of the filler on surrounding ground is not considered. This study considers the influence by which a pulling-out hole of a pipe foundation gives it to static characteristics of surrounding ground by using 3D elastic-plastic finite element analysis. The special qualities required for fillers injected into a pulling-out hole are also clarified in this study.

  14. ASSESSMENT ON LEAKAGE RISK OF SIDE IMPERVIOUS WALLS AT COASTAL LANDFILL SITES Download Article

    Ken-ichi Shishido and Shinya Inazumi
    • Article Type: Research Article
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    • Pages (86-93)
    • No of Download = 322

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    An evaluation method that can express the local leakage of leachate from joint sections in steel pipe sheet pile (SPSP) cutoff walls is discussed in this study. In particular, the evaluation of environmental feasibility (containment of leachates containing toxic substances) considering a three-dimensional arrangement and hydraulic conductivity distribution of the joint sections in the SPSP cutoff wall is compared with an evaluation that generally uses the equivalent hydraulic conductivity. This equivalent hydraulic conductivity assumes that the joint section and the steel pipe are integrated; therefore, the hydraulic conductivity is substituted with a uniform permeable layer. However, in an evaluation that employs the equivalent hydraulic conductivity, it is difficult to consider the local leakage of leachate containing toxic substances from the joint sections in the SPSP cutoff wall. This paper concluded that evaluations of the environmental feasibilities of the SPSP cutoff walls with joint sections must take into account the local leakage of leachates containing toxic substances from the joint section.

  15. WATER QUALITY AND SEDIMENTATION MODELING IN SINGKARAK LAKE, WESTERN SUMATRA Download Article

    Harman Ajiwibowo, R.H.B. Ash-Shiddiq and Munawir B. Pratama
    • Article Type: Research Article
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    • Pages (94-102)
    • No of Download = 334

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    Numerical modeling of the spatial distribution of water quality in Singkarak Lake, Western Sumatra, Indonesia is conducted. Field measurement data are collected, including bathymetry, water level, current velocity, and water quality data. The measured parameters in the water quality survey are the total suspended sediment (TSS), chemical oxygen demand (COD), biochemical oxygen demand (BOD), dissolved oxygen (DO) and phosphate (P). The finite element model is implemented using a surface-water modeling system (SMS). The model includes flow, constituent, and sedimentation models. Validation of the flow model is achieved by matching the current and the water elevation between the model and the field data. The validation shows good agreement. The model is aimed at observing yearly water quality and sedimentation change at the lake. The results from the constituent model show that the Sumpur and Sumani Rivers are having the greatest effect on the water quality of the lake in its northern and southern regions, respectively. A bed change of around 30–40 cm per year is found at the inlets of both of these rivers. Overall, the model shows that the lake water is only suitable for irrigation or fishing hatchery, and not for drinking water, according to the criteria for water quality standards in the Indonesian government’s Regulation 82 of 2001.

  16. DENSITY DISTRIBUTIONS WITHIN CERAMIC MATERIALS SATURATED FOR USE IN SUCTION MEASUREMENT Download Article

    Katsuyuki Kawai, Shinya Kikui, Naoki Yoshikawa and Takayuki Fuoto
    • Article Type: Research Article
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    • Pages (103-108)
    • No of Download = 290

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    Unsaturated soil contains air and water within the voids of the skeleton formed by soil particles. To investigate the complicated behavior of these materials through unsaturated soil testing, pore air and water pressure must be measured and controlled independently. For this purpose, a microporous ceramic material is used. The ceramic, which is installed in tensiometers and other experimental apparatus used for testing unsaturated soil, must be saturated using degassed water. The degree of saturation of the ceramic influences the accuracy of measuring and controlling suction. However, microporous ceramic is difficult to saturate. Currently, the ceramic material is saturated using empirical methods, the applicability of which have not been confirmed up until now. In this study, the effects of ceramic saturation methods were investigated. Three kinds of saturation methods, the vacuum method, the pressurization method, and the Berthelot method, were utilized. In each method, saturation time and the number of saturation cycles was varied. The saturated ceramic was also exposed to air drying to check the saturation effect, and X-ray computed tomography was used to visualize the degree of saturation of the ceramic. These efforts determined that trends in the distribution of saturation within the ceramic are dependent on saturation method.

  17. DEVELOPING REHEATED MOTORCYCLE EXHAUST FOR PM2.5 EMISSION Download Article

    Arinto Yudi Ponco Wardoyo and Hari Arief Dharmawan
    • Article Type: Research Article
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    • Pages (109-116)
    • No of Download = 285

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    Motor engine has been identified to produce particulate emission in different size distribution and has serious impacts on health and influence of air quality. Especially, PM2.5 which are known as particulate matters with the diameter less than 2.5 μm, induce a major health problem due to the reactive characteristic and the high exposure level in the human. In order to reduce the concentration of PM2.5 in the ambient, we have developed a new exhaust used to maximize the released combustion energy for reducing PM2.5 concentration. The exhaust was accomplished with a heating chamber and a copper net tube in the dimension of 25 cm in diameter and the varied length of 4 cm, 5 cm, and 6 cm. The tube was wired by copper with the diameter of 0.5 cm. The exhaust was characterized by measuring temperature and the capability in reducing PM2.5 concentration. The result showed that the exhaust worked well in reducing PM2.5 concentration with the efficiency reaching up to 24 % depending on the dimension of the net tube.

  18. INVESTIGATION OF CYLINDRICAL SPECIMEN COLLAPSE BEHAVIOR ON THE EXPERIMENT AND 3D SMOOTHED-PARTICLE HYDRODYNAMIC ANALYSIS Download Article

    Tetsuya Okano, Yukiko Sumi, Tsutomu Matsuo and Ryoichi Fukagawa
    • Article Type: Research Article
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    • Pages (117-122)
    • No of Download = 289

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    Smoothed-particle hydrodynamics (SPH) is a computational method used to simulate the dynamics of continuum media, such as solid mechanics and fluid flows. Much research has been conducted using this method to simulate the collapse behavior of soils; however, most of this research has focused on two-dimensional SPH analysis. There is currently little research into modelling the collapse behavior of soil using three-dimensional SPH analysis. Therefore, this paper presents the results of a collapse behavior study of cylindrical sand specimens, comparing experimental results with a three-dimensional SPH analysis. The experiments were conducted by pulling a cylindrical container from a column of sand and measuring the dimensions of the resulting diffusion cone. The frictional properties of the table surface and the rate of pulling were varied to determine their effects and compare analysis results. The diffusion cone geometries determined by SPH analysis showed good consistency with the observed experimental results, suggesting promising application of three-dimensional SPH analysis to the modelling of soil collapse behavior.

  19. CORROSION CURRENT DENSITY OF MACROCELL OF HORIZONTAL STEEL BARS IN REINFORCED CONCRETE COLUMN SPECIMEN Download Article

    Nevy Sandra, Keiyu Kawaai and Isao Ujike
    • Article Type: Research Article
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    • Pages (123-128)
    • No of Download = 330

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    Chloride-induced corrosion of steel bar in concrete is one of the main problems affecting the durability of reinforced concrete (RC) structures. Expansive products are formed due to corrosion at the interface between concrete and steel bar. In this study, the differences in the magnitude of the macrocell corrosion current density in RC column specimens cast using copper slag fine aggregate and fly ash replacement were examined. This study aimed at investigating corrosion formation with respect to macrocell corrosion current density. The experimental study was carried out through dry and wet (NaCl 10%) cycles for specimens with different cover depths, which was investigated by electrochemical measurements. The result shows that the largest macrocell corrosion current density was measured in the steel bars located at the upper part of reinforced column specimens for each case of the specimens with a cover depth of 30 mm. This could be partly attributed to the loss of the integrity of the steel and concrete interface which is examined based on the oxygen permeability in the upper and lower sides of segmented steel bars. The variation of oxygen permeability contributes to the macrocell corrosion formation especially in the steel bars affected by bleeding water. Besides the integrity between steel bars and concrete cover, the quality of concrete cover and variations in chloride ion concentrations are significant factors contributing to the macrocell corrosion formation.

  20. THE CHARACTERISTICS OF ROAD INUNDATION DURING FLOODING EVENTS IN PENINSULAR MALAYSIA Download Article

    Muhd Shahril Nizam Ismail, Abdul Naser Abdul Ghani and Zuhayr Md Ghazaly
    • Article Type: Research Article
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    • Pages (129-133)
    • No of Download = 337

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    Flooding can cause damage to infrastructure and has a devastating impact on daily life. Malaysia is located in a tropical region characterized by high quantity of rainfall. Damaged roads due to flooding prevent access for emergency and assistance purpose. The purpose of this study is to identify the flooding characteristics of inundated roads in Malaysia. It includes the parameters of flood water level, flood duration, and repeated flooding. Secondary data from relevant departments and agencies are gathered for the analysis. Flood statistics were obtained from the annual flood reports issued by the Department of Irrigation and Drainage Malaysia between 1991 and 2014. Road data as well as maps were collected from the Highway Planning Division, Ministry of Works Malaysia. In this study, flash flood was defined as flood that subsides in less than 6 hr. The study revealed that the average flood depths could be grouped into 0.3 m, 0.6 m and 1.0 m depths. However, in areas under tidal effect, the depths could exceed 1.0 m and it took longer for the flood to subside, up to two days. The result of this characterisation will be used to expand the study on the effect of inundated roads during flooding on the whole road structural system.

  21. DISCRETE PARTICLE SIMULATION MODEL FOR SLAKING OF GEOMATERIALS INCLUDING SWELLING CLAY MINERALS Download Article

    Yutaka Fukumoto and Satoru Ohtsuka
    • Article Type: Research Article
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    • Pages (134-139)
    • No of Download = 336

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    The slaking of geomaterials often causes some unexpected geohazards, such as slope failures, debris flows, rockfalls, and so on. In particular, the process of slaking is highly enhanced when the geomaterials include swelling clay minerals such as montmorillonite and saponite. In order to investigate the mechanisms of the slaking phenomenon from a microscopic point of view, this study presents a particle simulation model based on the discrete element method (DEM) that can reproduce the slaking process of geomaterials that include swelling clay minerals. The properties of swelling and shrinking are modeled by changing the diameter of the DEM particles which are assumed to comprise the swelling clay minerals and several sand particles. A series of simulations of the deformation of mudstone under a wet-dry cyclic condition is performed in both two and three dimensions. As a result of the analyses, the applicability of the proposed model to the slaking phenomenon is confirmed.

  22. EVALUATION OF SHEAR STRENGTH PARAMETERS OF GRAVEL SOILS WITH DIFFERENT SHAPE AND RELATIVE DENSITY Download Article

    José Carlos Solís Tito, Virgilio Chillihuani Chillihuani and Ignacio Fructuoso Solís Quispe
    • Article Type: Research Article
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    • Pages (140-145)
    • No of Download = 391

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    This article presents the results of large-scale direct shear tests in laboratory, to evaluate the parameters of shear strength of remodeled gravel soils at different degree of compaction, with a direct shear equipment built in the Soil Mechanics Laboratory of the Universidad Nacional de San Antonio Abad del Cusco, Perú. The cylindrical shear box with 30 cm diameter and 25 cm high, allows testing gravel soils with maximum size particles of 38.1 mm (1.5"). The four samples of gravel soils evaluated correspond to four quarries of the Cusco region, classified according to the Unified Soil Classification System as: GP (M-1), GM (M-2), GW (M-3) and GW (M-4). The tests were developed considering an incremental sequence of normal load to each sample of 49.0, 98.1 and 196.1 kPa. According to the results, for the four samples tested, the apparent cohesion was obtained in a range of 19.61 to 64.72 kPa and the internal friction angle in a range of 35.2° to 52.4°, for the states of relative density very loose, medium and very dense. These results allow us to conclude that the factors that affect the shear strength of the material are the density and the relative density of the remolded gravel samples, as well as the fragility at break and the rounded or angular shape of the soil particles.

  23. UNDERSTANDING OF FIRE DISTRIBUTION IN THE SOUTH SUMATRA PEAT AREA DURING THE LAST TWO DECADES Download Article

    Raden Putra, Edy Sutriyono, Sabaruddin Kadir and Iskhaq Iskandar
    • Article Type: Research Article
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    • Pages (146-151)
    • No of Download = 418

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    Peat fire is an annual catastrophic event in Indonesia, particularly in South Sumatra region during the dry season. Several previous studies have suggested that anthropogenic forces (land cover) contribute to peat fires. Analysis of the hotspots distribution on land cover types is needed to address peat fires in the futures. This study is aimed to evaluate the distribution of hotspots on the land cover type of the South Sumatra peat area during the last two decades (1997-2016). Remote sensing technique with visual image interpretation method using multitemporal satellite images is used to identify the variations of land cover in the study area. The results showed that the peat area of South Sumatra in 2013 dominated by ferns/ shrub (58%) and only about 10% covered by peat swamp forest (PSF). The largest hotspot distribution during the observation periods was spread in land cover types of Ferns/ shrub (34.808 hotspots) and Industrial Plantation (7.223 hotspots). Note that the densest hotspot located in the industrial plantation with an average of 37 hotspots/ 100 km2 / year. Meanwhile, only a small percentage of the hotspots located in PSF and occurred consistently over the last five years of observation periods. Based on results, the South Sumatra peatland is very vulnerable to burn during the dry season in the future. The government as policy maker must protect the existence of PSF and keep the ferns/ shrub from the fires and subsequent land cover changes (Industrial plantation or small holder area).

  24. SEDIMENT FLOW CHARACTERISTICS ON SEABED SUBJECTED TO STATIONARY WAVES WITH DIAGONAL INCIDENT WAVE LOADING NEAR LINE STRUCTURES Download Article

    Anh Quang TRAN, Kinya MIURA, Tatsuya MATSUDA and Takahito YOSHINO
    • Article Type: Research Article
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    • Pages (152-157)
    • No of Download = 394

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    Typical stationary waves are caused by overlapped the incident and reflected wave, when the plane wave vertically meets a line structure. In this case characteristic sediment flow behavior is observed and seabed is suffered from configuration change such as erosion and deposition. In more general situations where plane wave meets line structures in diagonal direction, however, overlapped waves would behave in three-dimensional manner. The stability of structures subjected to stormy ocean waves or tsunami depends on the integrity of seabed foundation ground, as well as the wave pressure acting directly on the structures. Thus, reliable analysis method for evaluating the sediment flow on seabed and associated erosion-deposition is needed. The present study aims to clarify the sediment flow characteristics induced by the diagonal incident and reflected waves which meet line structure and broken line structure, with seabed effective stress response to sea wave loading into account. Erosion-deposition behavior was quantitatively examined based on the calculated results.

  25. MULTI-CHANNEL FIBRE BRAGG GRATING SENSORS FOR UNIAXIAL COMPRESSION TEST ON LIMESTONE ELASTICITY BEHAVIOUR Download Article

    Balarabe Wada Isah, Hisham Mohamad and Niraku Rosmawati Ahmad
    • Article Type: Research Article
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    • Pages (158-163)
    • No of Download = 399

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    In rock mechanics, measurement of small strain response is the most basic and significant means of assessing rock mechanical and elasticity behavior. To overcome the difficulties of mounting, handling many cables, dependency of the stain responds measured to the properties of the sensor components, this paper intends to explore the applicability of a novel multi-channel Fiber Bragg Grating sensors (MC-FBGs) for determining small strain response of cylindrical rock specimen under uniaxial compression test for assessing deformability properties. The concept, design and embedment technique of MC-FBGs employed in the experiment are illustrated concisely. To analyze the stress-strain respond of a cylindrical limestone specimen, two axial FBGs placed diametrically opposite to each other along the longitudinal axis of the specimen and two radial FBGs embedded opposite to each other circumferentially within the central one-third portion of the specimen were adopted for axial and radial strain response measurement. In addition, two electrical resistance-based strain gauges (SG), one mounted axially and the other attached radially along the circumference, are used for comparative measurements with the FBGs. The values of unconfined compressive strength, Young's modulus, crack initiation and crack damage stress obtained from MC-FBGs and SG are in good agreement. It could be deduced that MC-FBGs can measure small strain response of limestone, stiffness anisotropy as well as measure the vital stages of rock failure mechanisms proficiently. MC-FBGs could serve as an alternative approach for determining reliable, accurate and precise compressive strain response of a limestone.

  26. VOLUME LOSS CAUSED BY TUNNELLING IN KENNY HILL FORMATION Download Article

    Chee-Min Khoo, Thanath Gopalan, Nurfatin ‘Afifah Abdul Rahman and Hisham Mohamad
    • Article Type: Research Article
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    • Pages (164-169)
    • No of Download = 381

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    The Klang Valley MRT Sungai Buloh – Kajang (SBK) Line, Malaysia’s first mass rapid transit line involved the construction of 9.5km twin bored tunnels in the densely populated urban area of Kuala Lumpur city. The underlying geological conditions can be distinctly demarcated to two main formations namely Kuala Lumpur Limestone and Kenny Hill Formation, of which 5.262km of bored tunneling was carried out in the Kenny Hill Formation. The bored tunnel construction in the Kenny Hill Formation was undertaken with the use of Earth Pressure Balance (EPB) Tunnel Boring Machine (TBM). The ground settlement due to tunneling is largely dependent on the volume loss induced by the tunnel excavation. At present, little information has been published on actual volume loss encountered during tunnel construction in the various soil types in Malaysia. Surface settlement markers among other instruments that were placed at selected intervals along the SBK Line tunneling route as an instrumentation and control measure offer an opportunity to evaluate and back analyze the ground response due to tunneling works. This paper presents and discusses the volume loss caused by EPB TBM tunneling in the Kenny Hill Formation. Back analysis on trough width parameter from the available data has also been carried out. The findings of this study could be useful as a reference for future tunneling projects in similar ground conditions.

  27. EFFECT OF NON-PLASTIC FINES ON UNDRAINED RESPONSE OF FINE SAND Download Article

    M Akhila, K Rangaswamy and N Sankar
    • Article Type: Research Article
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    • Pages (170-175)
    • No of Download = 180

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    Silty soils are widespread in many countries, particularly in the United States, China, and India; hence it is essential to get an idea of the response of such soils under different forms of loading. In this paper, the results based on undrained triaxial tests, under static as well as cyclic loading, which were carried out on the silty sands (fine sand mixed with non-plastic fines at different percentages) are presented. The samples were prepared at the required unit weight (Dr = 50%), saturated by using back pressure and cell pressure increments and consolidated isotropically. Each consolidated sample is then subjected to static/cyclic loading. The results of the static triaxial testing showed that the non-plastic fines have a significant influence on the behaviour of fine sand. The dilation tendency decreases with the addition of fines. In the case of cyclic triaxial testing, as the fines content increases, the rate of generation of excess pore water pressure and axial strain on cycles of loading was found to increase and hence the liquefaction susceptibility.

  28. WIND WAVE MODELING IN NATUNA SEA: A COMPARISON AMONG SWAN, SEAFINE, AND ERA-INTERIM Download Article

    Yati Muliati, Ricky Lukman Tawekal, Andojo Wurjanto, Jaya Kelvin and Widodo Setiyo Pranowo
    • Article Type: Research Article
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    • Pages (176-184)
    • No of Download = 421

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    This research was conducted to verify the wave height hindcasting in Natuna Sea using the SWAN (Simulating Wave Near-shore) model, which is compared with the results of hindcasting from SEAFINE (SEAMOS South Fine Grid Hindcast) and ERA-Interim. This is expected to support research on wave characteristics based on wave forecasting for 10 years in the seas among Java, Sumatera, and Kalimantan. So the purpose of this research was to test the SWAN modeling of existing models. If the results of the comparison show similar wave distribution patterns, then the settings in the SWAN model can be used for SWAN modeling in Indonesia. The SWAN model is run with the third-generation mode (GEN3), which allow wind input, quadruplet and triad interactions, whitecapping, and breaking. Comparison of hindcasting results among SWAN, SEAFINE, and ERA-Interim produces a similar wave distribution pattern, with a good correlation coefficient for 5 stations (R=0.78-0.84). The SWAN model produces the lowest Hs estimates, while the SEAFINE model produces the highest Hs of all stations. Significant wave height (Hs) 100 years return period for all stations in Natuna Sea from SWAN is 2.97-3.37 m, ERA-Interim 4.01-4.13 m, and SEAFINE 5.24-5.67 m. The setting up of wave hindcast in this research will be helpful for improving the level of sea wave hindcast in the seas among Java, Sumatera, and Kalimantan.

  29. REMOVAL OF ACID ORANGE II DYE BY GRANITIC NANO-ZERO VALENT IRON (nZVI) COMPOSITE Download Article

    Nur ‘Aishah Zarime, Wan Zuhairi Wan Yaacob and Habibah Jamil
    • Article Type: Research Article
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    • Pages (185-192)
    • No of Download = 373

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    The study highlights the effectiveness of nanoscale zero-valent iron (nZVI) composite in removing Acid Orange II dye. In this study, granitic residual soil has been used as supported material to stabilize the nanoscale zero-valent iron (nZVI) and to improve its adsorption capacity. The physical, chemical, mineralogical and morphological properties of the successfully synthesized granitic nano zero valent iron (Gr-nZVI) have been analyzed by Brunnaer–Emmett–Teller (BET) surface area, X-ray Photoelectron Spectroscopy with Auger Electron Spectroscopy (XPS-AES), Field Emission Scanning Electron Microscopy (FESEM), and X-Ray Diffraction (XRD). The batch adsorption tests for the granitic residual soil (Gr) and the granitic nano-zero valent iron (Gr-nZVI) on Acid Orange II have been conducted to determine the effectiveness of both materials in dye removal. The five effects analyzed in the Batch test are concentration, dose, pH, kinetic and temperature. It was found that Gr-nZVI has higher absorption capacity compared to Gr. The effectiveness of Gr-nZVI composite in dye adsorption is due to the dispersion of nZVI particles on granitic soil particles, consequently providing more sites for adsorption. The results suggest that Gr-nZVI has potential as low-cost adsorbent for Acid Orange II removal from synthetic dye wastewater.

  30. DEPENDENCE OF TUNNEL DEFORMATION DUE TO ADJACENT PILE UNDER LOADING ON TUNNEL GEOMETRY Download Article

    Prateep Lueprasert, Pornkasem Jongpradist, Kodchamon Ruangvirrojanakul and Suchatvee Suwansawat
    • Article Type: Research Article
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    • Pages (193-199)
    • No of Download = 470

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    With rapid urbanization, large number of tunnels with various dimensions have been constructed for transportation and utility systems in many big cities. At the same time, the constructions of infrastructures using a pile foundation system are also necessary in urban area. With limited space, the existing tunnels can be inevitably impacted by the newly constructed pile-supported structures. With various design criteria of tunnel lining, the size and thickness are varied from project to project. With an adjacent pile under loading, different degrees of impact on these tunnels are expected. This study numerically investigates the effect of tunnel diameter and lining thickness on tunnel deformation due to adjacent pile under loading. The MRTA and WMA tunnels in Bangkok subsoil are chosen as the reference cases for investigation. From a series of parametric study, a relationship between the tunnel deformation and dimensionless parameter, which include the size and thickness of lining, can be successfully established.

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