Articles

  1. FINITE ELEMENT ANALYSIS OF EWECS COLUMNS WITH VARYING SHEAR SPAN RATIO Download Article

    Fauzan, Ruddy Kurniawan and Zev Al Jauhari
    • Article Type: Research Article
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    • Pages (1-7)
    • No of Download = 331

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    A new hybrid structural column system called Engineering Wood Encased Concrete-Steel (EWECS) was developed for low and high seismic zones. Experimental studies on the seismic behavior of EWECS composite columns with varying shear span to depth ratio (shear-span ratio) have been conducted by one of the authors. To complement and validate the experimental program, finite element analysis (FEA) on EWECS columns with varying shear span ratio ranging 1.0 to 2.0 under constant axial and lateral cyclic loads are summarized. This numerical analysis uses finite element program, ANSYS APDL v.14, to investigate the structural performance of the EWECS columns, which was compared with experimental results. A detailed three-dimensional (3D) nonlinear FE model of three composite columns with varying shear-span ratio, subjected constant axial and lateral cyclic loads are performed. The FEA results showed that the shear-span ratio affects the maximum shear strength and failure mode of the EWECS columns. The maximum strength of the columns increased with decreasing shear-span ratio. The stress distribution on the FE models represents the failure mode of the EWECS column specimens well. More damages on the columns are observed with decreasing shear-span ratio. In general, good agreement between the experimental data and the FE model's output in terms of the seismic performance and failure mode is observed.

  2. MEETING THE CHALLENGES OF ENGINEERING A SUSTAINABLE FUTURE Download Article

    David Thorpe
    • Article Type: Research Article
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    • Pages (8-18)
    • No of Download = 262

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    Engineers have a significant role in the sustainable development and management of resources. This responsibility encompasses the three generally accepted dimensions of sustainability – environment, economic and social - and applies to engineering projects throughout their life cycle. Sustainable engineering practice is supported by professional engineering associations, such as Engineers Australia, which includes the promotion of sustainability as a principle of its Code of Ethics. It has also been given impetus by the recent Paris Agreement on climate change. However, while there has been considerable progress in this field, there is much work required to achieve a truly sustainable future. While the industry has a major role in promoting and encouraging sustainable practices in engineering projects, educators also have a significant role in this process, through developing and fostering the knowledge and skills of sustainability in engineers. At the undergraduate level, this task is normally undertaken through courses that teach the principles of sustainable engineering practice. A major challenge for educators, however, is the ongoing development of the knowledge and skills of sustainable engineering taught in such courses. While postgraduate courses can achieve this objective, the majority of practicing engineers are unlikely to be able to undertake the detailed formal study. Meeting this gap between sustainable engineering knowledge and its implementation, therefore, presents challenges to educators. Possible options proposed include an ongoing commitment by government and society to sustainability in engineering projects, ongoing implementation of innovative sustainable engineering practices, and lifelong learning in sustainable engineering practices by professional engineers.

  3. ASSESSMENT OF NUTRIENT LOADS AND SELF-REMEDIATION: A CASE STUDY OF THE SOUTH RANGSIT CANAL IN THAILAND’S PATHUM THANI PROVINCE Download Article

    Boontarika Thongdonphum, Kittima Vanichkul, Saming Champasri and Jirapon Kulkham
    • Article Type: Research Article
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    • Pages (19-23)
    • No of Download = 306

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    This research investigates the effects of seasonal variability (rainy and dry seasons) and nutrient transfer patterns on the nutrient loads (dissolved inorganic nitrogen (DIN) and orthophosphate phosphorus (P)) and the self-remediation of the south Rangsit canal in Thailand’s central province of Pathum Thani. The results showed that the physicochemical characteristics of the canal water severally varied from season to season, with the ammonium-nitrogen (NH4+-N), nitrite and nitrate-nitrogen (NO2-+NO3--N) and orthophosphate phosphorus (PO43--P or P) concentrations in the range of 10.79-85.35; 56.70-135.79; and 0.74-5.66 μmol L-1, respectively. The DIN and P loads were 5.05 and 0.40 tons/day in the rainy season (September); and 5.12 and 0.32 tons/day in the dry season (March). The relative remediation efficiency (EFRRR) were mostly negative, especially in the dry season, indicating the inadequate self-remediation and nutrient input-output imbalance. The findings also showed that water mass transfer directions influenced the self-remediation and nutrients accumulation in the study area.

  4. SEA LEVELS IN A CHANGING CLIMATE Download Article

    Maria McCrann, John Russell, Daniela Ionescu and Bandita Mainali
    • Article Type: Research Article
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    • Pages (24-30)
    • No of Download = 297

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    The rise of sea levels could have devastating consequences for coastal settlements, and it can easily be one of the most critical effects of climate change. Thus, all factors affecting sea levels need to be considered. One of the factors discussed in this paper is the natural variability of sea levels, which originates from the oscillation of the planets and solar activity. The effect of the Sun’s activity on Earth’s climate has been identified since the 1800s. However, there are still many unknowns regarding the mechanisms connecting the Earth’s climate to the variation in solar irradiance. Climate modelling that implements the solar sciences is a novel approach that accounts for the considerable effect that natural factors have on the climate, especially at regional level. This paper discusses the noticeable effect that planet oscillations have on the Sun’s activity, which gives a very good correlation with the observed patterns in global surface temperatures, rainfall records and sea levels. In agreement with many studies that have identified a 60-year cycle in the variation of Earth’s temperature, it is expected that surface temperatures will reach a trough of the cycle around 2030-2040. Furthermore, considering the influence of the Solar Inertial Motion, a solar slowdown is predicted for Solar Cycles 24 and 25, which will create a weak grand minimum. It is anticipated that this weak grand minimum will be reflected in a dampening effect of global temperatures, and a subsequent moderation in the rate of sea level rise.

  5. 3 DIMENSION REAL TIME IMAGES OF RAINFALL INFILTRATION INTO UNSATURATED SOIL SLOPE Download Article

    Aniza Ibrahim, Irfana Kabir Ahmad and Mohd. Raihan Taha
    • Article Type: Research Article
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    • Pages (31-35)
    • No of Download = 264

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    Failure of soil slope is mainly due to infiltration of rainfall. The complexity of rainwater path infiltrate soil slope can be predicted using commercial software, and volumetric moisture content at the infiltrated slope area can be measured by Time-Domain-Reflectometry (TDR). Prediction of rainwater path is based on parameters obtained by laboratory works, and volumetric water content using TDR can only available at the point of insertion. In this research, an innovative method called Electrical Capacitance Volume Tomography (ECVT) was used in geotechnical engineering application in determining the real-time imaging of rainwater infiltration into unsaturated soil slope. This method also achieves permittivity value through the experiments and converted to volumetric water content using equation. A soil sample obtained from slope failure around National Defense University of Malaysia (NDUM) campus during monsoon season was used in the research. The results revealed real-time 3 dimensions (3-D) images of rainwater infiltrated into soil slope were produced through image reconstruction method of ECVT. Volumetric water content was also achieved using permittivity value attained by ECVT result. Images which permittivity indicated the infiltration of rainwater through soil slope were clearly shown in the results. This innovative technology is expected to improve the understanding of soil slope behavior especially in for rainfall infiltration that relates to soil stability.

  6. A STUDY ON THE EFFECTIVENESS OF LIQUID SMOKE PRODUCED FROM PALM KERNEL SHELLS IN INHIBITING BLACK POD DISEASE IN CACAO FRUIT IN VITRO Download Article

    M. Faisal, Tjut Chamzurni and Hiroyuki Daimon
    • Article Type: Research Article
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    • Pages (36-41)
    • No of Download = 254

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    The effectiveness of liquid smoke made from palm kernel shells in inhibiting black pod disease (Phytopthora palmivora) in cacao fruit was studied. Palm kernel shells underwent pyrolysis in a slow-pyrolysis reactor at 280°C–400°C. The resulting liquid smoke was then distilled at a temperature of 200°C. The observed parameters were incubation period and spotting diameter. The experimental design was completely randomized, with a 4 × 6 factorial pattern having four repetitions and consisting of two factors. Both temperature and concentration significantly affected the incubation period of the fungi causing black pod disease. Additionally, the liquid smoke concentration had a strong influence on the spotting diameter. Phenolic compounds and acetic acid contained in the liquid smoke serve as antimicrobials and are bacteriostatic. Although the maximum phenol level was found at 280°C, the longest incubation period occurred in liquid smoke produced at a pyrolysis temperature of 360°C. Thus, 360°C was the optimum temperature for producing liquid smoke to inhibit black pod disease caused by P. palmivora in cacao.

  7. TESTING AND ANALYSIS OF COLD-FORMED STEEL CHANNEL SECTION WITH NOTCH Download Article

    Mohd Syahrul Hisyam Mohd Sani, Fadhluhartini Muftah and Muhammad Isha Ismail
    • Article Type: Research Article
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    • Pages (42-49)
    • No of Download = 284

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    Cold-formed steel (CFS) channel section is a construction material that often been used in the building and still in the research for utilizing in structural element. The advantages of the CFS channel section such as lightweight, anti-corrosion and etc are becoming so interesting in selecting it as a roof purlin, roof truss system and storage rack. For having the structural element with the strong, safe and stable condition, the study of the CFS with the notch is carried out to determine the behavior. The parametric study is taking place to determine the suitability of notch pattern whether the notch depth and spacing are affecting the ultimate load of the CFS channel section column and beam. The study of the CFS channel section is divided into two parts, the first part is to examine the ultimate load of the column in varies of notch depth and the second part is to determine the ultimate load of the beam in varies of notch spacing. By referring the study of the notch depth on CFS channel column section, the result of the ultimate load is obtained to have the reduction about 19-80% of the variation of notch depth when compared with the normal section. Although, the CFS channel beam section with variation notch depth is influenced by approximately 4-14% when compared with CFS channel normal beam section.

  8. INFLUENCING PARAMETER OF SELF PURIFICATION PROCESS IN THE URBAN AREA OF CIKAPUNDUNG RIVER, INDONESIA Download Article

    Yonik Meilawati Yustiani, Mia Nurkanti, Neneng Suliasih and Annisa Novantri
    • Article Type: Research Article
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    • Pages (50-54)
    • No of Download = 243

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    Self-purification process is an important process in the effort of recovering the river condition itself. This process usually takes place naturally. However, several inhibitions might disturb the process. It was indicated by the slow deoxygenation rate and unhealthy river condition. This research aims to identify the influence parameters responsible for the slow of self-purification in the Cikapundung River, which is located in the urban area of Bandung City, Indonesia. The river water samples were taken and analyzed in the laboratory to obtain the water quality. The deoxygenation rate was also calculated based on the Slope Method after data was acquired from 10 days daily observation. Research showed that the value of urban river deoxygenation rate is relatively low. The low value of the rate of deoxygenation led to the difficulty in rivers to purify themselves. Pollutants inhibiting the process include phenol, detergent, and heavy metals, which are contaminating the river over the maximum standard. Biologically, the decomposer consists in the river is few. It leads to a slow organic degradation rate. The condition is representing the low capacity of self-purification of the Cikapundung River which is caused mainly by chemical and biological parameters.

  9. DEVELOPMENT OF SPECIFIC ELECTROCHEMICAL BIOSENSOR BASED ON CHITOSAN MODIFIED SCREEN PRINTED CARBON ELECTRODE FOR THE MONITORING OF CAPTAN FUNGICIDE Download Article

    Porntip Wongkaew, Buddhapala Wongkaew, Suwita Saepaisan and Panupong Thanutong
    • Article Type: Research Article
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    • Pages (55-62)
    • No of Download = 324

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    Harmful chemicals predominantly used in modern agriculture for pest control have raised a long-term accumulation in the environment and serious problems concerning food safety and health. Excellent detection tools for environmental monitoring are thus urgently needed. The recent biosensor technology is proposed to fulfill this purpose. In this study, an expedient biosensor for captan fungicide determination has been fabricated using its specific reacting enzyme glutathione-s-transferase (GST) covalently immobilized on natural biopolymer chitosan (Chi). The screen-printed carbon electrode (SPCE) has been selected as a basal platform for the biosensor development. Modification of SPCE was made by self-assembled deposition of 1% chitosan in 1% acetic acid solution onto the basal SPCE. Progressive characteristics of the assembled SPCE-Chi-GST have been clearly approved by atomic force microscopy, impedance spectroscopy and cyclic voltammetry (CV). Two sequential oxidation peak currents arose in the electrochemical behavior analysis of captan in the presence of GST substrate electrolyte solution by CV and linear sweep voltammetry (LSV). Dose-response to various captan concentrations was investigated in the range 0 – 20 μg/ml by LSV and a similar good linear relationship between peak current and concentration of captan could be obtained by both oxidation steps with the limit of detection (LOD) at 0.2 μg/ml. Thus the sensitive, rapid, inexpensive and miniature quantitative system for captan monitoring could now be successfully achieved by this proposed biosensor.

  10. A COMPARATIVE SETTLEMENT PREDICTION OF LIMESTONE BLENDED MATERIALS USING ASAOKA AND HYPERBOLIC METHOD Download Article

    Erica Elice Saloma Uy and Jonathan Rivera Dungca
    • Article Type: Research Article
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    • Pages (63-69)
    • No of Download = 247

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    The construction industry in the Philippines is predicted to sustain its growth up to 2021 because of the infrastructure plan of the government according to the Philippine Infrastructure Report. With this, the demand for construction materials would increase and as a result, an increase in prices is expected. To address this problem, an alternative material must be explored. A promising material is a limestone because it is abundant in the Philippines. These materials can be used as a material for structural fill or embankment. In order to determine the material’s possible use its capacity to withstand loads must be checked. In this study, its compressibility is the main focus. Its consolidation parameters were first obtained by performing one-dimensional consolidation test. Limestone wastes were mixed with a conventional soil and it is proportioned at 0%, 20%, 40%, 60% and 100%. After the consolidation parameters were determined, the data from the consolidation test were used to predicting the settlement behavior of the material. The Asaoka method and hyperbolic method were used in the prediction and the results of both methods were compared. Based on the results, it was observed in the one-dimensional consolidation test, the limestone waste used had a minimal effect on the compressibility of the conventional material used. Lastly, the prediction of the hyperbolic method is larger for some mix proportions.

  11. ACCURACY OF DISTRIBUTED SYSTEMS TOWARDS INDUSTRY 4.0: SMART GRIDS AND URBAN DRAINAGE SYSTEMS CASE STUDIES Download Article

    Poonpakdee, P. and Koiwanit, J.
    • Article Type: Research Article
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    • Pages (70-76)
    • No of Download = 269

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    With significantly improving the overall manufacturing operations commonly known in smart factory practices, vertical and horizontal integrations of various components are introduced throughout the entire value chain. The proliferation of smart factory practices introduces the fourth industrial revolution called Industry 4.0. Industry 4.0 creates new challenges and the application of networked manufacturing systems is one of the important features required to handle the systems in an efficient way by communicating and processing information to each other. Distributed systems provide coordination to allow the global information to be available for a better decision making and consequently achieving high efficiency. This connectivity helps for a better decision making and therefore achieve high efficiency. However, the evaluation on the accuracy of global information between different architectures of distributed systems (centralized systems and decentralized systems) has little work mentioning in the state of current manufacturing systems under the conception of Industry 4.0. As a result, this research will fill the gap by providing an accuracy of the decentralized system over the centralized system together with their sensitivity analysis. In this study, the decentralized system is built based on the concept of Epidemic protocols or Gossip-based protocols, while the centralized system is a simple client-server. The epidemic protocol is a bio-inspired communication paradigm that imitates the behavior of virus when the outbreak occurs in a community. The accuracy in both systems has been monitored by means of simulations. The effects of message loss to the accuracy of centralized and decentralized systems are studied. By comparing the system accuracy between both systems, it was found that the accuracy of the decentralized system is generally more accurate when the system is used for a long period. The accuracy tends to be lower down especially when the information is not completely distributed, while the accuracy of the centralized system receives an excessive suffer from message loss.

  12. VULNERABILITY ASSESSMENT OF SURIGAO METRO WATER DISTRICT UNDER SEISMIC HAZARD Download Article

    Sheena I. Better and Lessandro Estelito O. Garciano
    • Article Type: Research Article
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    • Pages (77-82)
    • No of Download = 320

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    Earlier this year, Surigao Del Norte, a province in the Philippines experienced a 6.7 magnitude earthquake. The severe ground movement caused some of the buried pipelines to be pulled-out from their supports. This type of failure occurs when the ground strain during extreme seismic excitation exceeds the strain capacity of the buried pipe. The failure of the pipes resulted in the loss of water that was vital for post-earthquake recovery efforts. In this regard, there is a need to re-assess the vulnerability of the buried pipes of the water network. In this paper, a probabilistic seismic hazard analysis (PSHA) was employed to estimate the seismic hazard within the concession area. Past seismic data that can significantly affect the target structure is used for this purpose. The buried water lifeline system of Surigao Metro Water District (SMWD) was chosen as the target lifeline. An appropriate ground motion prediction equation (GMPE) was used to develop the uniform hazard response spectra for the site. To assess the vulnerability of the pipes three damage states were considered: major, moderate and minor. The probability of major, moderate and minor damage to each pipe was determined using Monte Carlo simulation. Subsequently, fragility curves were obtained.

  13. STUDY OF WATER FLOW AND RETENTION IN CLAY-SAND LINERS Download Article

    Muawia Dafalla1, Gamal Abdel-Nasser G. and Ahmed Al-Mahbashi
    • Article Type: Research Article
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    • Pages (83-90)
    • No of Download = 247

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    This research paper presents a simulation study to predict the percolation of water through soil liners using numerical modeling with HYDRUS-2D. The soil liners included compacted clay/sand mixtures of 0 to 25% clay at 5 to 30 cm thickness. The cumulative water flux or hydraulic barrier at drain layer at the end of simulation period reached a ratio of 0.81, 0.54, 0.29 and 0.09 of water flux at a top profile with no soil liner. The soil liners of 25 and 30 cm thickness with 20% and 15% clay had lesser percolation or water flux at drain layer by about 0.21 and 0.44 compared to water flux at top layer with no soil liner. Using a modeling approach efficient liner systems can be designed for use in water harvesting projects or landfill covers. The modeling and simulation are dependent on the hydraulic conductivity of the compacted soil liner, soil water characteristics curves as well as irrigation and rainfall rates.

  14. INVESTIGATION OF CURING PERIOD OF CEMENTITIOUS ADHESIVE AND PERFORMANCE OF RUST PREVENTION Download Article

    Yoichi Mimura, Vanissorn Vimonsatit and Isamu Yoshitake
    • Article Type: Research Article
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    • Pages (91-97)
    • No of Download = 241

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    A steel-concrete composite structure needs generally mechanical shear connectors such as headed studs to ensure efficient load resistances. As an alternative to shear studs, a type of cementitious adhesives has been developed to connect a steel-concrete composite structure. The unique feature of this adhesive is the improved bond performance with fresh concrete which depends on the curing age of the adhesive. This paper presents the outcome of fifteen flexural tests of elemental steel-concrete composite beams with various curing ages of the adhesive to investigate the appropriate curing period. Shot blasting steel plate and the un-shot blasting steel plate were prepared to examine the bond performance from the surface condition of the steel plate. The result of the flexural tests indicates that the bond performance between the steel plate and the concrete is optimum when the curing periods are 7 - 14 days. The tests with longer curing age produce similar bond performances with the tests at 7 days. Use of steel plate without shot blasting may be undesirable for the composite structure using the adhesive. In addition to the flexural tests, 8 deformed bars with and without adhesive coating were exposed to a field condition to investigate the rust preventive performance of the adhesive. The deformed bars without the adhesive had already corroded at 5 days after exposure. The observation showed the deformed bar with the adhesive was hardly deteriorated after 200 days.

  15. SPATIAL VARIATIONS OF SURFACE WATER QUALITY AND POLLUTION SOURCES IN KHLONG U-TAPAO RIVER BASIN Download Article

    Saudee Maprasit, Rotchanatch Darnsawasdi, Vichit Rangpan and Chaisri Suksaroj
    • Article Type: Research Article
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    • Pages (98-103)
    • No of Download = 237

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    Multivariate statistical analysis, cluster analysis, parametric analysis, as well as factor analysis was applied to analyze water quality dataset including 9 parameters at 21 sites of the Khlong U-Tapao river basin in Songkhla province, Thailand, from 2007–2015 to investigate spatial variations of water quality and identify potential sources of pollution. Using cluster analysis to classify the three-periods of water quality variation in each monitoring site has shown 3 water quality measures: high, moderate and low. Using parametric study to describe variations of water quality and the significantly identified land use variables affecting water quality, such as urbanization and industrial land use which are sources of pollution in upstream. However, in midstream, Economical urbanization is the pollution source while agricultural land use is the pollution source in downstream. Factor analysis identified that the major pollutants in the upstream were turbidity and conductivity matter from soil erosion in the rainy season and industrial wastewater, in the midstream, the biochemical oxygen demand of organic matters from wastewater discharge from domestic settlements were the main pollutants while in downstream, nutrients from agricultural practices were the major pollutants. From upstream to downstream, bacterial pollutants were the main pollutants from all activities. These results provide fundamental information for developing better water pollution control strategies for the Khlong U-Tapao river basin.

  16. NUMERICAL SIMULATION OF STAGED BRACED EXCAVATION IN SAND ~ O6 MRT STATION Download Article

    Samal Hama Salih, Mohammad Mirza Hassan, Jim Shiau and Zakaria Hossain
    • Article Type: Research Article
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    • Pages (104-111)
    • No of Download = 291

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    A numerical model for long-term drained analysis of staged excavation is developed and validated with a case history in this paper. Kaohsiung O6 station in Taiwan is selected for this purpose. A complete soil-structure interaction is considered in the current analysis which involves structural elements for diaphragm wall and strutting with preloading. FISH scripts are used to simulate staged strutted excavation using the finite difference program FLAC. Within the framework of drained analysis for excavation in the sand, dewatering is performed for each stage of the excavation work. Field monitoring data from other published sources are used to compare with the results produced by the numerical model. The main purpose of this paper is to demonstrate the usefulness of the development in assisting design and monitoring construction of deep braced excavation. The developed model can be used to assist future design and construction projects.

  17. PLASTIC FLOW HETEROGENEITY AND FAILURE OF BIMETAL MATERIAL Download Article

    Svetlana Barannikova, Lev Zuev and Yulia Li
    • Article Type: Research Article
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    • Pages (112-117)
    • No of Download = 273

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    The aim of this paper was to display the kinetics of Lüders band (LB) propagation of bimetallic material on the yield plateau at the microscale level. The localization patterns of plastic deformation in the process of uniaxial tension were obtained by the non-contact method of recording the fields of displacement vectors. The microstructure of the interfaces with the user results of optical, atomic force and scanning microscopy showed that in the direction of the pearlite steel to the austenitic form there are structural components: the weakened zone of the ferrite layer; a hardened section of the ferrite layer dark-pickling layer from the side of the austenitic steel. Plastic deformation of a bimetal began from the nucleation of the Lüders band on the boundaries of the bimetal on stress raisers with higher hardness due to the diffusion effect. In the main layer, the Lüders band was limited to a pair of fronts moving in opposite directions along the bimetal axis with different velocities. The cladding layer did not suppress the formation of Lüders bands, led to an increase in the propagation velocity of Lüders band fronts in the base layer.

  18. STUDY ON LANDSLIDE CATEGORY BASE ON TEMPORALSPATIAL CHARACTERISTIC DISTRIBUTION IN NORTHERN VIETNAM USING SATELLITE IMAGES Download Article

    Thuy Thi Thanh LE and Seiki Kawagoe
    • Article Type: Research Article
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    • Pages (118-124)
    • No of Download = 235

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    North Vietnam has a lot of landslide-prone regions due to heavy rainfall or tropical storms, steep slopes on mountainous sides and human activities such as road or house constructions. Heavy rainfall events are estimated by climate change in the future. Therefore, it is necessary to understand landslide characteristic due to rainfall variation. This paper applied Landsat satellite images and calculated NDIs (Normalized Difference Indexes) to evaluate the condition of vegetation, soil and water and detected 43 landslide points in North Vietnam. Landslide points are then evaluated to compare digital geographic information data to divide landslide type. As result, three typical types of landslides are classified as landslide caused by rainfall on construction (road etc..) sites (Type 1), a landslide caused by rainfall on natural slopes (Type 2), and landslide caused by rainfall and water drawdown on banks of reservoirs or streams (Type 3). Considering the Landsat result Type 2 and Type 3 consist larger proportions compared to those in historical data. This means that many landslides would occur in mountainous areas that far from residential or road areas (Type1).

  19. APPLICATION OF HEC-RAS AND ARC GIS FOR FLOODPLAIN MAPPING IN SEGAMAT TOWN, MALAYSIA Download Article

    Noor Suraya Romali, Zulkifli Yusop and Ahmad Zuhdi Ismail
    • Article Type: Research Article
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    • Pages (125-131)
    • No of Download = 256

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    Nowadays, a risk-based flood mitigation concept has received more attention rather than the conventional flood control approach in reducing the impacts of flooding. With the intention to assist in the management of flood risk, flood modeling is useful in providing information on the flood extent and flood characteristics. This paper presents the application of HEC-RAS model to the development of floodplain maps for an urban area in Segamat town in Malaysia. The analysis used Interferometric Synthetic Aperture Radar (IFSAR) as the main modeling input data. Five distribution models, namely Generalized Pareto, Generalized Extreme Value, Log-Pearson 3, Log-Normal (3P) and Weibull (3P) were tested in flood frequency analysis to calculate extreme flows with different return periods. Using Kolmogorov-Smirnov (KS) test, the Generalized Pareto was found to be the best distribution for the Segamat River. The peak floods from frequency analysis for selected return periods were input into the HEC-RAS model to find the expected corresponding flood levels. Results obtained from HEC-RAS model were used in ArcGIS to prepare floodplain maps for different return periods. The results indicated that most of the inundated areas in the simulated 100 year return period were also affected by 2011 historical floods. For 100 years flood simulation, the inundated area was almost 5 times larger than the simulated 10 years’ flood.

  20. NANOSTRUCTURAL CHARACTERIZATION OF GLUTATHIONE-S-TRANSFERASE IMMOBILIZING CHITOSAN MODIFIED SCREEN PRINTED CARBON ELECTRODE BY ATOMIC FORCE MICROSCOPY Download Article

    Buddhapala Wongkaew, Porntip Wongkaew, Panupong Thanutong and ChitsanuphongThanutong
    • Article Type: Research Article
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    • Pages (132-139)
    • No of Download = 247

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    Immobilization of a bio-recognition element to the surface of a functional working electrode is fundamental for effective biosensor development. In this study, the enzyme glutathione-s-transferase (GST) that constitutes a protein superfamily involving various distinct chemical transformations was introduces as a versatile tool for the sensing of environmental toxicants. Functional electrode surface was made by self-assembly of a great bioscaffold chitosan onto screen-printed carbon electrode surface concerning to its excellent covalent bonding binding of biomolecules. To enhance the enzyme proximity, glutaraldehyde was employed as an assisting bifunctional cross-linker. The self assembled chitosan layer and the GST immobilizing nanostructural features were explored by morphological imaging and several quantitative analyses such as surface grain size and distribution, power spectrum density (PSD) algorithm, fractal dimension character and other important surface roughness parameters via atomic force microscopy (AFM). Vertical aggregation of the successive layer was clearly verified in all quantitative approaches. Exceedingly, a better understanding in the direction of aggregation along with the growth mechanism was obtained by PSD analysis and the fractal dimension values gained around 2.27 for modified chitosan surface and 2.02 for GST immobilized chitosan modified screen-printed carbon basement could thus imply for the diffusion limited model in this growth mechanism.

  21. ROLE OF GOVERNMENT AND PRIVATE SECTOR IN MARINE ECOTOURISM RELATED TO CONSERVATION OF BIODIVERSITY IN SERIBU ISLANDS Download Article

    Lily Surayya Eka Putri and Kristiyanto
    • Article Type: Research Article
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    • Pages (140-147)
    • No of Download = 268

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    Ecotourism has relation with conservation of biodiversity which recently shows bad condition on the marine ecosystem. This research analyzed how the role of government compared to the private sector was conducted in Pramuka and Air Island based on the type of ecological zone and further conformity of ecotourism was assessed based on biodiversity of living organisms in both islands. Line intercept transect method was used in this study stretched along the parallel 85 m into the coastline with three replications over 25 m. Combination of 100 m Line intercept transect method and 20 m diameter of circular transect method inside were used to measure identify plants. Bird species was observed by the distance sampling point count method. Interview with local people surrounding islands was also conducted to get the information on anthropogenic activities. The study showed that coral diversity in Pramuka and Air Island were in moderate level (1.00 <H '<3.00), nevertheless live coral coverage in Pramuka Island was 29.17% of 73.44% total coral coverage lower than Air Island (49% of 55.62%). Seagrass species found in Pramuka Island were 6 species and only 3 species were found in Air Island whereas mangrove species was lower in Pramuka Island than Air Island. For ecotourism conformity, Pramuka Island was confirmed for recreation and seagrass ecotourism category whereas all tourism categories were confirmed in Air Island. Despite ecotourism in both islands likely destroyed the environment, conservation of biodiversity on marine ecosystem seemed ineffectively managed or even ignored by government neither private sector. Recovery by nature seems to play a greater role in biodiversity conservation in both islands.

  22. MONOTONIC BEHAVIOUR OF SAND UNDER TORSIONAL LOADING WITH DIFFERENT CONFINE STRESS Download Article

    Navid Khayat
    • Article Type: Research Article
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    • Pages (148-153)
    • No of Download = 308

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    This study assessed the effects of anisotropy in sands with various confining stresses. The tests conducted in this research include 20 hollow cylinder torsion shear tests under torsional loading conducted on Tehran sand with high angularity. The confining stresses of the samples were 100, 200 and 400 kPa, and the effect of the inclination angle of the major principal stress to the vertical axes was also studied. In each confine stress three inclination angle 15, 30 and 60 degrees were applied. According to the results, an increase in the alpha will result in a more contractive behavior in the sands. The effect of anisotropy also becomes more obvious, as the confining stresses increases; however, it was found that the mechanical properties of sands changed markedly with confining stress. To explain the effect of particle shape on the mechanical behavior of sand, with its increase the soil sample behaved in an isotropic manner and the shear strength of the sample decreases.

  23. STUDY OF BIO-GROUT TREATED SLOPE MODELS UNDER SIMULATED RAINFALL Download Article

    R.C Omar, Hairin Taha, R. Roslan and I.N.Z Baharudin
    • Article Type: Research Article
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    • Pages (154-159)
    • No of Download = 230

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    Previous data reported that soil erosion in Malaysia was directly related to rainfall trends. This phenomenon could affect the overhead transmission towers which are at risk of collapsing due to slope failure. For soil stabilization, chemical grouting such as cement, lime and acrylamides were generally applied to enhance the physical properties of the soil. However, some of the chemical additives used in the grouting suspension may be toxic and hazardous to both humans and the environment. Thus, it is important to look for alternative grouting substances that are safe and sustainable. Recently, a new soil improvement technique based on carbonate precipitation by microbial activities from vegetable waste has been developed as bio-grout. This study was aimed to investigate the effectiveness of bio-grout from the vegetable waste in reducing soil loss due to rainfall impact. Soil samples were collected from an eroded slope nearby a transmission line in Perak and molded into 45˚ slope models in a custom-made box. A simple rainfall simulation was performed on the untreated and treated soil samples mixed with bio-grout for 30 days. The results showed that the soil loss of treated samples has been significantly reduced from 34.6 g to 13.5 g. Scanning electron microscopy showed aggregated particles occupying the empty spaces of the treated soils. Evidence of bio-mediated microbial activity was indicated by the presence of microorganisms in the bio-grout liquid. The bio-grout from vegetable waste proved to be an effective and eco-friendly new grouting material for soil erosion control.

  24. PHYSICAL MODELING FOR MEASURING THE EFFECTIVENESS OF SINGLE CURTAIN PILE FOUNDATION BREAKWATER IN INTERMEDIATE WATER DEPTH Download Article

    Harman Ajiwibowo
    • Article Type: Research Article
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    • Pages (160-166)
    • No of Download = 222

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    A combined Curtain and Pile Foundation's breakwater called the Single Curtain Pile Foundation Breakwater (SCPFB), was designed to dissipate wave energy in an intermediate water depth instead of constructing a rubble mound-type breakwater. (TC). The physical modeling of the SCPFB is was conducted at the Ocean Wave Research Laboratory in Institut Teknologi Bandung in a 2D wave flume to measure the breakwater’s transmission coefficient in the intermediate water depth condition The waves generated in the wave flume were monochromatic. The scaling applied the principle of Froude similarity, where the Froude number of the model equaled to the Froude number of the prototype. Wave heights and wave periods data were observed by both visual observation and wave probes. The incoming wave heights and transmitted wave heights before and after the SCPFB, respectively, were measured and processed to obtain the TC. The relationships between TCand non-dimensional variables such as the relative incident wave steepness, water depth, and curtain draft were obtained. Comparisons with similar research are shown.

  25. DERIVATION OF THE CRITICAL RAINFALL LEVEL NEEDED FOR AN EARLY FLOOD WARNING IN THE UPPER CITARUM RIVER BASIN INDONESIA Download Article

    Dhemi Harlan, Iwan K. Hadihardaja, Arno Adi Kuntoro, Enung and Dony Faturachman
    • Article Type: Research Article
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    • Pages (167-174)
    • No of Download = 201

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    Rainfall is one of the common triggering factors of the flood. Bandung City is located in the Upper Citarum river basin. Parts of the city, such as Bojong Sari, Bojong Soang, Cieunteung and Andir Sub district, are in natural floodplains. During the wet season, these areas are frequently flooded. This study analyzed the critical rainfall level that potentially caused flooding. The Hydrologic Engineering Centres Hydrologic Modelling System (HEC-HMS) rainfall-runoff model and the 1D HEC-RAS model were applied. A six storm pattern was simulated to determine the critical rainfall that generated the water depth that was equal to or greater than the critical water surface depth at specific points in the river. Hypothetical rainfall events are used to investigate the response of the river basin at critical cross-sections. It can be considered by different temporal distributions. The amount of rainfall is assumed to be distributed uniformly. The conclusion of this research is that the storm pattern (rainfall depth and rainfall duration) plays a crucial role in determining the critical rainfall at the flood location. The critical rainfall in a specific location is affected by the position at the river cross-section (in the upstream or the downstream area) and the bank full capacity of the river cross-sections.

  26. CONTROL TECHNOLOGY FOR SOFT ROCK ROADWAY IN INCLINED COAL SEAM: A CASE STUDY IN NUI BEO MINE, QUANG NINH, VIETNAM Download Article

    Dao Viet Doan, Hongchao ZHAO, Jiantao CAO, Chen Yong and Wang Meng
    • Article Type: Research Article
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    • Pages (175-182)
    • No of Download = 307

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    The large deformation of soft rock roadway is still a main concern for a large number of coal mines, particularly in terms of these located at the inclined seam with the large section. This paper presented a successful case study conducted at Nui Beo coal mine in Vietnam. Borehole peep detector was first put into the application to investigate the distribution of fractures to clarify the influenced range of surrounding rock. Then, the finite element analysis software (i.e. RS2) program is adapted to establish the numerical model aiming at exploring critical parameters for bolt support. Finally, a combined support technology including primary support by using a high prestressed bolt and reinforced technology by cable have been proposed and put into application. The results revealed that 1) the rheological strain is closely related to time, it is about 105 days from the firstly caving to be stable, 2) the maximum displacement of the ribs and roof-to-floor are 28mm and 47mmrespectively. The deformation of surrounding rock obtained from case study was used to evaluate the effectiveness of proposed support technology. The use of high prestressed bolt can maintain the stability of surrounding rock incline coal seam. Moreover, the experience can be used as a reference for other mines in Vietnam.