Articles

  1. DETERMINING PEAK DISCHARGE FACTOR USING SYNTHETIC UNIT HYDROGRAPH MODELLING (CASE STUDY: UPPER KOMERING SOUTH SUMATERA, INDONESIA) Download Article

    Rosmalinda Permatasari, Dantje Kardana Natakusumah and Arwin Sabar
    • Article Type: Research Article
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    • Pages (1-5)
    • No of Download = 451

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    Synthetic unit hydrograph methods are popular and play an important role in many water resources design especially in the analysis of flood discharge of ungagged watersheds. These methods are simple, requiring only watershed characteristics such as area and river length and in some cases it may also include land use characteristics. Therefore, these methods serve as useful tools to simulate runoff from ungagged watersheds and watersheds undergoing land use change. To develop a synthetic unit hydrograph, several techniques are available. Several most popular unit hydrographs methods such as Nakayasu, Snyder-Alexeyev, SCS, and GAMA-1 are popular and commonly used in Indonesia for computing both peak discharge rate and the shape of flood hydrograph. This paper presents a simple approach for determining a consistent dimensionless unit hydrograph based on mass conservation principles. The results for peak discharge in several hydrographs methods are Nakayasu 607.32 m3/sec, SCS 668.62 m3/sec, ITB-1 675.42 m3/sec, ITB-2 642.805 m3/sec in periode time return 2 years.

  2. IMPROVING BIOSORPTION OF CU(II)-ION ON ARTIFICIAL WASTEWATER BY IMMOBILIZED BIOSORBENT OF TROPICAL MICROALGAE Download Article

    Astri Rinanti, Melati Ferianita Fachrul, Rositayanti Hadisoebroto and Mawar Silalahi
    • Article Type: Research Article
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    • Pages (6-10)
    • No of Download = 417

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    This research purposes to study the role of microalgae in tropical environment – isolated fromWastewater Treatment Plant (WWTP) Setiabudi, Jakarta, Indonesia – on biosorption of Cu(II) ion in heavy metal wastewater. The effects of pH and contact time on the rate of metallic biosorption were examined to reach the greatest biosorption efficiency. Microalgae diversity analysis through phenotypic approaches showed that the microalgae community was comprised of 3 species of Chloropyceae i.e Ankistrodesmus braunii, Chlorella sp., and Scenedesmus quadricauda var quadrispina. Immobilized biosorbent from microalgae was prepared by oven-drying, grinding, and entrapping the microalgae biomass into polymeric matrix of alginate. The sorption properties of biosorbent was characterized by using infrared spectroscopy and SEM micrograph analysis. The optimization of sorption parameters was conducted in batch systems using Cu(II)-artificial wastewater of 300 ppm with pH arrangement of 2-7 and the contact time arrangement of 60, 90, 120, 180, 240 minutes. During the experiment, the Chlorophyceae free and Na-alginat immobilized biomass were added. The research showed that either free and immobilized biomass could adsorb Cu(II) metal ion and reduce its concentration into 25-50 ppm. A maximum biosorption by the alginate-immobilized biosorbent obtained at pH 3,0 and contact time of 180 minutes with 43% absorption efficiency. Sorption properties of microalgae biomasses were indicated by various functional groups presence on biosorbent that could bind heavy metals compared to others. The research proved that the alginate-immobilized biosorbent was highly effective for the treatment of Cu(II)-artificial wastewater and that tolerant cholorophyceae could act as an effective biosorbent in further optimization.

  3. SELF-ORGANIZING MAP BASED SURROGATE MODELS FOR CONTAMINANT SOURCE IDENTIFICATION UNDER PARAMETER UNCERTAINTY Download Article

    Shahrbanoo Hazrati Y. and Bithin Datta
    • Article Type: Research Article
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    • Pages (11-18)
    • No of Download = 267

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    Identification of unknown groundwater contaminant sources is a complex problem. The complexities arise mainly due to the uncertainties related to the hydrogeologic information, sparsity of measurement data and unavoidable concentration measurement errors. The process of contaminant source identification with sparse and limited concentration measurement data especially when the hydrogeologic parameters are uncertain requires an efficient procedure. The existing methodologies to tackle this problem in real world cases usually require huge computational time and the solutions may be non-unique. The goal of this study is to evaluate a developed methodology to characterize the groundwater contamination sources in a heterogeneous, multi layered aquifer. This developed methodology utilizes the Self Organizing Maps (SOM) algorithm to design the surrogate models for source characterization. The most important advantages is that in this methodology, the trained SOM based surrogate models is directly utilized for groundwater contaminant source characterization without the necessity of using a separate linked simulation optimization model. The performance of the developed methodology is evaluated by using deterministic hydraulic conductivity values, and uncertain hydraulic conductivity values. These results indicate that the developed methodology could efficiently approximate groundwater flow and transport simulation models, and also characterize unknown groundwater contaminant sources in terms of location, magnitude and release history.

  4. PLASTICITY INDEX EFFECTS ON MECHANICAL BIFURCATION: SOILS AND SOFT-SEDIMENT DEFORMATION Download Article

    Naoto Kaneko, Jun Muto and Hiroyuki Nagahama
    • Article Type: Research Article
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    • Pages (19-25)
    • No of Download = 461

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    Yielded specimens have various deformation patterns depending on loading stages and stress ratios in spite of the same geomaterials (e.g. soils and soft-sediment). Failure patterns of materials bifurcationally change to diamond, bulge and a pair of oblique shear patterns. Symmetry of deformation patterns (e.g. shear band patterns) has been illuminated by bifurcation analysis of governing equation based on Cam-clay model. Plasticity index tested by Casagrande liquid limit device and plastic limit instruments is known to describe mechanical characteristics (e.g. compressibility) of soils. Relationship between plasticity index and mechanical bifurcation controls the evolution of deformation patterns. From the view point of concept of plastic potential, we show that plasticity index theoretically determines deformation patterns of soils on the basis of the bifurcation analysis. Furthermore, because deformation facies of rocks are described by mean ductility of rocks similar to the concept of plasticity index, we point out that mean ductility controls mechanical bifurcation of the geologic materials such as soft-sediments.

  5. EFFICIENCY OF PUBLIC TRANSPORTATION USING GLOBAL NAVIGATION SATELLITE SYSTEM (GNSS) Download Article

    Riza Putera, Anisa Santoso, Irene Sondang, Oky Pratama, Garrin Nandhito and Esty Suyanti
    • Article Type: Research Article
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    • Pages (26-30)
    • No of Download = 458

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    Motor vehicles are one of the biggest air pollution contributor in the city. Pollution getting worsened by poor public transport system in the city that caused lack of public services. In order to minimize the impact, so the focus not only by reducing the quantity of vehicles but also by managing the use of motor vehicles becomes more efficient. Through Global Satellite Navigation System (GNSS) as precise navigation tool, the patterns of transport system such as distance, duration, number of vehicle can be estimated accurately and more efficient. This research applied GNSS in the public transportation at Universitas Indonesia. Mode of transportation which we used in this research is campus buses or “Bis Kuning”. We used quantitative experimental integrated with Geographic Information Systems (GIS). The results are GNSS can predict the patterns of campus buses, from the patterns we tried to connect with users of Bis Kuning satisfaction.

  6. THE INTEGRATION OF GEOGRAPHY INFORMATION SYSTEM (GIS) AND GLOBAL NAVIGATION SATELITE SYSTEM-REAL TIME KINEMATIC (GNSS-RTK) FOR LAND USE MONITORING Download Article

    Komara Djaja, Riza Putera, Akmal Fathu Rohman, Irene Sondang, Garrin Nanditho and Esty Suyanti
    • Article Type: Research Article
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    • Pages (31-34)
    • No of Download = 544

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    Limited open space area requires accurate monitoring to maintain changes in land use that is not suitable with city spatial planning. The difference between spatial planning and existing land Use should be minimized. Currently, land Use monitoring using Global Positioning System (GPS) and processed by Geography Information System (GIS) but the result has a deviation from the existing land Use. Within GNSS-RTK as a new approach will correct the result of GPS become more precise map of land Use. This research will test a GNSS-RTK that is applied to the land Use belongs to the campus of Universitas Indonesia. The land use will be divided as built up area and open space. The method used is quantitative experimental integrated with Geographic Information Systems (GIS). The results are, 1) the difference of land Use area with GPS and GNSS-RTK, 2) GNSS-RTK can get more accurate data than GPS. Base on the result, the conclusion is through GNSS-RTK and GIS, land use monitoring can be more effective because the highly precision of land area.

  7. EFFICIENCY OF POLYSTYRENE INSULATED CEMENT BLOCKS IN ARID REGIONS Download Article

    Muawia A Dafalla and Mohammed I. Al Shuraim
    • Article Type: Research Article
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    • Pages (35-38)
    • No of Download = 471

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    Polystyrene insulated cement blocks emerged recently as an energy saving building material in construction practice. Expanded polystyrene of 5cm thickness or more is introduced as a middle fill layer within the cement block in order to improve the thermal properties of walls. This study is made to investigate the efficiency of insulation provided by this type of treatment. Two chambers were constructed in an open area where the walls are subjected to variable weather conditions ranging from moderate to hot weather for a period of three months. The arid region selected was Riyadh, Saudi Arabia. Temperature was found to vary between day and night through this period from as low as 9 ºC to as high as 48 ºC. Each chamber is built in the form of four block walls 20 cm in thickness, one meter wide and one meter high. The chambers were founded on grade slabs with a wood board used as a roof. The two chambers are identical except for the type of blocks; one is built using polystyrene insulated blocks and the other without insulation. Construction was carried out the same way as used in local practice. Thin mortar layer is used for bonding blocks. 5TE sensors and a data logger were used to record ambient temperature and temperature inside each chamber. Hourly records throughout the testing period were used to evaluate and compare the insulated and non-insulated blocks. It was found that the improvement provided by the polystyrene cement blocks is less efficient in hot temperature than in moderate temperature. The insulation provided by the blocks as constructed is very poor and heat transfer is enabled through mortar filled gaps and joints. The temperature gradient has influence on the polystyrene insulation material.

  8. FOOTING WITH INVERTED PYRAMIDAL PROTRUSIONS FOR SETTLEMENT CONTROL IN SANDY DEPOSITS Download Article

    Chee-Ming Chan and Muhammad Arif Amzar Mohd. Yusuf
    • Article Type: Research Article
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    • Pages (39-43)
    • No of Download = 489

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    This paper examines the feasibility of using an innovative footing with a corrugated base to enhance the load-bearing capacity of shallow foundation, and to reduce the substructure’s subsidence as a whole or differentially. The corrugated base consists of inverted pyramidal protrusions which give a 3-fold advantages: (1) the pointed tips help smoothen the process of installation on site, (2) the protrusions provide additional contact surface between the foundation and the soil for better load-bearing, (3) the corrugated base entraps soil between the individual protrusions, improving the foundation’s stability against settlement and sliding. Scaled models of the 8 cm x 8 cm footing were produced using 3D printing: CONTROL- smooth base, Design A corrugated base with16 inverted pyramidal protrusions of 2 cm x 2 cm x 2 cm each, and Design B- corrugated base with 64 inverted pyramidal protrusions of 1 cm x 1 cm x 1 cm each. Both designs had the same contact surface area with the soil, though the penetration depth of the pyramids and the space between the protrusions varied. Maintained load tests were carried out in simulated soil beds to determine the improved performance of the foundation. It was shown that the corrugated slabs reduced settlement up to over 85 % compared with the conventional smooth-base footing, with Design B giving slightly better results. It was also observed that the larger pyramidal protrusions (Design A) tended to entrap air between them, forming air cushions which resisted further penetration of the corrugated base into the soil, i.e. inhibiting mobilization of the maximum load-bearing capacity.

  9. RELIABILITY ANALYSIS OF REINFORCED CONCRETE SLAB BRIDGES Download Article

    Ali Mahmoud, Shadi Najjar, Mounir Mabsout and Kassim Tarhini
    • Article Type: Research Article
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    • Pages (44-49)
    • No of Download = 357

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    Empirical expressions for estimating the wheel load distribution and live-load bending moment are typically specified in highway bridge codes such as the AASHTO procedures. The objective of this paper is to assess the reliability levels that are inherent in concrete slab bridges that are designed based on the simplified empirical live load equations in the AASHTO LRFD procedures. To achieve this objective, typical one and two-lane straight bridges with different span lengths were modeled using finite-element analysis (FEA) subjected to HS20 truck loading, tandem loading, and standard lane loading per AASHTO LRFD procedures. The FEA results were compared with the AASHTO LRFD moments in order to quantify the biases that might result from the simplifying assumptions adopted in AASHTO. A reliability analysis was conducted to quantify the reliability index for bridges designed using AASHTO procedures. To reach a consistent level of safety for one lane and two lane bridges, the live load factor in the design equation proposed by AASHTO LRFD needs to be revised by increasing the live load factor to 2.07 for one lane and 1.8 for two lanes. The results will provide structural engineers with more consistent provisions to design concrete slab bridges or evaluate the load-carrying capacity of existing bridges.

  10. DOMESTIC RECHARGE WELLS FOR RAINWATER-HARVESTING IN DENPASAR CITY, BALI - INDONESIA Download Article

    Lilik Sudiajeng, I Wayan Wiraga, I Gusti Lanang Parwita, and Gede Santosa
    • Article Type: Research Article
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    • Pages (50-57)
    • No of Download = 541

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    This research is to create the design of shallow recharge wells for harvesting rainwater in Denpasar City, Bali-Indonesia. The growth of the tourism industry is increasing rapidly. It has been able to accelerate the economic growth, but also followed by some negative effects, including rapid growth of population, changes in land use, reduced the catchment area and groundwater exploitation for tourism infrastructure development. The result showed that in several strategic areas have shown an indicator of water crisis, especially in North and East Denpasar. Based on the permeability analyses, the recharge area was in the north and a little part of west Denpasar. The rainfall was between 1500 - 1750 mm/year with 4 wet months a year. The shallow groundwater level reaches 16.10 m below ground level in the North, while in the West was 18.2 m with the maximum infiltration rate was 0.00000054 mm/sec. Based on those data, it has been designed the ergonomics shallow recharge wells for rainwater harvesting to offset the domestic water usage. The analyses showed that if all 220.150 households make at least one shallow recharge wells, it can harvest rainwater about 222.40 l/sec, and is able to return about 63.87% of water which should be recharge to the ground. In conclusion, making one-recharge wells for each household has not been able to recover the domestic water usage. It is recommended to create another innovation for water conservation program such as building the recharge wells along the drainage tunnel.

  11. A MODEL OF PARTICIPATION IN A WATER REHABILITATION PROJECT OF A LOCAL GOVERNMENT UNIT IN THE PHILIPPINES Download Article

    Gerby R. Muya, Merlita Medallon and Nelson Tenorio
    • Article Type: Research Article
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    • Pages (58-63)
    • No of Download = 535

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    To eradicate water pollution, a local government in the Philippines has implemented a water rehabilitation project called ―Adopt-A-River Project. The project mobilized the local communities to preserve and maintain a clean and safe environment. Promoted through the use of communication media, Adopt-A-River Project has been implemented along the three main tributaries of the area. This study was designed to propose a model of participation considering the level of awareness and perception on the project and the level of participation of the 327 residents. Data were gathered using a validated researcher-made questionnaire with reliability index of 0.970 on perception items and 0.897 on level of participation. Data revealed that local group discussion (52%) is the most commonly used medium of communication in increasing awareness of the project. This is in addition to radio, television, newspaper and the internet. The use of different media resulted in the respondents being informed of the project which led to their involvement in decision-making and consultative role. The information about the project was disseminated using words that are simple and easy to understand. The project was accepted by the residents and participation was heightened. The perception level has an effect on the information level by 0.737. Path analysis using 14 variables showed a good fit with Chi-square = 0000 and GFI, NFI and CFI having values of 0.99 and RMSEA of 0.026. Significant predictors of participation are perception (p=.000) and awareness (p=.000).

  12. ESTIMATING FLEXURAL RELIABILITY OF CARBONATED RC BRIDGE BEAMS USING PARTICLE FILTER Download Article

    Jonathan Sanchez, Samantha Louise Jarder, Nestor de Ocampo, Allen Teruel and Lessandro Estelito O Garciano
    • Article Type: Research Article
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    • Pages (64-69)
    • No of Download = 454

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    Many of our reinforced concrete structures today are ageing at the same time subjected to carbonation. It occurs when atmospheric carbon dioxide reacts with the components of the hydrated cement. In this regard, the authors estimated the probability of flexural failure of a deteriorated reinforced concrete (RC) beams subjected to carbonation. In the reliability analysis, the resistance degrades over time due to a change in the concrete compressive strength caused by carbonation. The load was modeled as a uniformly distributed on a simply supported beam. The results of the Monte Carlo simulation of an example bridge showed a decrease in the compressive strength due to carbonation. To estimate the present state of the RC beams, particle filter was used in conjunction with observation data from rebound hammer tests on the bridge.

  13. SIMPLIFIED ACID EXTRACTION METHODS OF HEAVY METAL IONS FROM CONTAMINATED SOILS Download Article

    Hyoil Jeon and Seungkyung Park
    • Article Type: Research Article
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    • Pages (70-74)
    • No of Download = 473

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    Early detection of heavy metal contaminations of soil and ground water has great importance for human health. In this study, single acid extraction methods have been tested and evaluated for the extraction of heavy metal ions for rapid and on-site soil sample preparations. Parametric studies have been performed including sample to acid volume ratio, extraction time, and acid concentration, and the performance of the proposed method has been compared with standard laboratory based protocol using soil samples spiked with target metal ions. The proposed protocol utilizing three different single acids (EDTA, HNO3, HCl) has shown the comparable extraction efficiency over ~80% for heavy metal ions of major concerns, Pb, Hg, and As. Compared to standard method based on aqua regia digestion, single acid extraction provides reduced processing steps and reagent volume, possibly enabling the on-site processing of contaminated soils and analysis.

  14. ENHANCED OIL RECOVERY USING BIOTRANSFORMATION TECHNIQUE ON HEAVY CRUDE OIL Download Article

    Abdullah Al-Sayegh, Yahya Al-Wahaibi, Saif Al-Bahry, Abdulkadir Elshafie, Ali Al-Bemani and Sanket Joshi
    • Article Type: Research Article
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    • Pages (75-79)
    • No of Download = 569

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    Abundance of heavy crude oil resources and costly enhanced oil recovery (EOR) techniques necessitate development of inexpensive heavy oil recovery methods. Microbial EOR (MEOR) techniques are environmentally friendly and need little input of energy to produce MEOR agents. One potential application of MEOR is in the biotransformation of heavy oil where bacteria break heavier fractions of heavy crude oil to lighter compounds; thus, improving oil recovery. In this study, two spore forming bacteria: Bacillus subtilis AS2 and Bacillus licheniformis AS5, which were isolated from heavy oil (13.3 °API) contaminated soil samples from a heavy oil field, Oman, were tested for their biotransformation abilities. Bacterial growth was analyzed by optical density measurements and heavy crude oil recovery was determined by core flooding experiments. At aerobic biodegradation flask experiments, M2 medium spiked with glucose had the highest bacteria growth and crude oil biodegradation in comparison with: (1) M2 medium with no added chemicals and (2) M2 medium spiked with sodium thiosulfate. At anaerobic in situ conditions Berea sandstone core flooding experiments, additional 2.9% and 3.1% of residual oil saturation was recovered by B. subtilis AS2 and B. licheniformis AS5 respectively after one week of incubation. By increasing the incubation time and inoculation percentage for isolate AS5, the oil recovery increased to 5.0%. When glucose was added to M2 medium, AS5 oil recovery increased to 16.4%.The results showed that locally isolated bacterial strains have the potential for biotransformation of heavy oil and enhanced oil recovery.

  15. SIMULATION–OPTIMIZATION TRUCK DISPATCH PROBLEM USING LOOK – AHEAD ALGORITHM IN OPEN PIT MINES Download Article

    Achmad Yusaq Faiz Fadin, Komarudin and Armand Omar Moeis
    • Article Type: Research Article
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    • Pages (80-86)
    • No of Download = 431

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    Material transportation in open-pit mines area contributes to 50% of the operating costs. Therefore, efficiency on the material transportation, specifically in truck dispatching problem needs to be done in order to get the best dispatching rules for the allocation of trucks and loaders. This research uses look-ahead algorithm approach as a new method to solve truck dispatch problem in open-pit mines area. The proposed approach was developed by simulation and optimization model in solving the truck dispatch problem using real data-situation. The dispatching result aims to answer the question where and when should a truck go so that could maximize the number of production and provide significant operating cost savings to the mining industry. This study uses a discrete event simulation to test several scenarios methods of truck dispatch, including LP-Gap, the percentage of LP-Gap, multi-stage algorithm and look-ahead algorithm. The results of the research shows that the look-ahead algorithm scenario gives the highest result with the number of production, productivity of loaders, productivity of trucks with block and without block; 43,533 ton, 64.44%, 80.53% and 63.47%.

  16. DESIGNING LINER SHIPPING NETWORK IN INDONESIA WITH DEMAND UNCERTAINTY Download Article

    Komarudin, Ayudya Triastika and Irvanu Rahman
    • Article Type: Research Article
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    • Pages (87-93)
    • No of Download = 387

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    The problem of maritime logistics in Indonesia lies on the unbalanced trade flow between west and east region of Indonesia. Since the east region does not have many comodity to be transported, to accommodate the demand on the east region liner shipping companies have to face the increasing amount of operational costs which makes the company failed to achieve the optimal profit. According to that situation, liner shipping companies needs a service network design which accomodate demand on each ports and give maximum profit. This research uses stochastic modeling to best portray the real condition of maritime logistics by taking demand uncertainty into consideration. The algorithm used in this research aims to determine the ship routes, ship types, and the cargo allocation that yields higher profits. The result was presented as a comparison between deterministic and stochastic modeling. The result shows that companies can yield higher profit if they use stochastic modeling approach from the initial decision making stage. The proposed solution method was designed to optimize Indonesian liner shipping services.

  17. MULTI-PERIOD MARITIME LOGISTICS NETWORK OPTIMIZATION USING MIXED INTEGER PROGRAMMING Download Article

    Komarudin, Mellianna Fiannita C. Purba and Irvanu Rahman
    • Article Type: Research Article
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    • Pages (94-99)
    • No of Download = 543

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    Indonesia, as an archipelago country, is dependent to maritime logistics on transporting goods and transportation. However, its performance is still poor, indicated by high cost of logistics. Designing maritime logistics network is crucial for shipping company on developing their business. The objective of this research is to design a liner shipping logistics network on multi-period planning horizon using mixed integer programming with maximizing profit as objective function. Three given scenarios (fixed route and fleet size, fixed route but fleet size may increase, and random route and fleet size) are analyzed for ten years within three different conditions of demand (demand equals to forecasted demand, demand equals to forecasted demand of certain period, and demand is constant). The result shows that the second scenario gives the most satisfying result of objective function in profit and fleet allocation variables. The third scenario gives the highest profit on every condition and first scenario has the lowest number of vessels. The profit margin between the third and second scenario on each condition are 2.99%, 1.32%, and 0.004 % and fleet allocation gap between the first and second scenario are 1 ship, 1 ship, 0 ship respectively.

  18. A STUDY ON FACTORS AFFECTING GEOPOLYMERIZATION OF LOW CALCIUM FLY ASH Download Article

    Yuyun Tajunnisa, Masaaki Sugimoto, Tetsuya Sato and Mitsuhiro Shigeishi
    • Article Type: Research Article
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    • Pages (100-107)
    • No of Download = 517

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    This paper presents some factors affecting geopolymerization of low calcium fly ash for geopolymeric matrices. Low calcium fly ash samples were collected from two different coal-powered facilities: an Indonesian fertilizer plant and a Japanese power plant. Several series of tests were conducted using various ratios of fly ash to activator as well as ratios of activators to sodium hydroxide molarity. Each matrix consisted of a set molar ratio of three variations of Si/Al (1.5, 2, 2.5), Na2O/SiO2 (0.3-0.38), H2O/SiO2 (2.8 to 3.5), H2O/Na2O (9 to 10.6), and mass ratio of water/solid (0.31 to 0.45). The setting time of Japanese ash-matrices were longer than Indonesian ash. The compressive strength revealed that the Japanese and Indonesian matrices with activator ratios of 1.5 achieved 47.7 and 57.5 MPa respectively, while activator ratios of 2.5 reached 50.9 and 50.5 MPa. In addition, microstructural characterizations–XRF, XRD, SEM, EPMA-were performed. This study concludes that even ashes categorized as the same class, their mineral composition is different. Furthermore, coal combustion techniques modify ash particles, which in turn causes differences in setting time, while strength is not significantly affected.

  19. LIFE DATA ANALYSIS OF SERVER VIRTUALIZED SYSTEM Download Article

    Biju R Mohan and G Ram Mohana Reddy
    • Article Type: Research Article
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    • Pages (108-115)
    • No of Download = 349

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    The use of reliability metrics and life data analysis has received considerable attention recently in the software engineering literature. Life data analysis under the actual operational profile can, however, be expensive, time consuming or even infeasible. In this paper, a systematic approach has been adopted in order to reduce the experimentation time for estimating time to failure of a server virtualized system. The study of time to failure (TTF) is very essential in server virtualized system, because it is the crux of the cloud computing infrastructure. In order to meet service-level agreements (SLAs) like availability, reliability and response time, prediction of reliability metrics like mean time to failure (MTTF), life distribution etc are indispensable. The most important contributions of this paper are the reduction of experimental time, and the life data analysis of the server virtualized systems which were not addressed so far. Experimental results demonstrate that there is only four percentage deviation from the observed results from the Normalized Root Mean Square Error and resulting in 96% accuracy of predicting MTTF.

  20. LASER LAND LEVELING FOR CROP YIELD AND WATER EFFICIENCY IN EASTERN AFGHANISTAN Download Article

    Shakerullah Hashimi, Homayoon Ganji, Masaaki Kondo, Ryoei Ito and Takamitsu Kajisa
    • Article Type: Research Article
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    • Pages (116-121)
    • No of Download = 533

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    Herein, the impact of land layout improvement (LLI) and laser land leveling (LL leveling) has been studied. In Afghanistan, LLI and LL leveling has been undertaken by the Ministry of Agriculture Irrigation and Livestock through an important project On-Farm Water Management (OFWM) in five regions, wherein poor farm layout and existence of uneven fields, unnecessary bunds, and ditches are responsible for significant water losses (at the farm level) and yield reduction, thereby increasing water and labor demand. Moreover, irrigation systems are used to supply water to the highest levels of the fields. However, this practice often leads to over-irrigation and the reduction of resources and yield. The present field experiments comprised two parts, Farm-A LLI and LL leveling. Farm-B was the control farm; all other practices were maintained constant in Farm-B except for LLI and LL leveling. Farm-A was separated into 29 small, even, and appropriately irrigated fields of less than 0.075 ha. The entire Farm-A area was leveled, and the size of each field increased to 0.19 ha and farm area was enlarged by (6%). The number of fields decreased from 29 to 12, and the number of water inlets decreased from 39 to only 14. These reductions showed a decrease in the labor requirements. In the two fields (Farm-A (leveled) and Farm-B (unleveled)), water demand for the production of wheat, corn, and eggplant decreased by 21%, 27%, and 17%, whereas the yield increased by 21%, 40%, and 38%, respectively. Furthermore, water productivity increased by 39%, 53%, and 37%, respectively.

  21. GENERATION OF LIGHT EMISSION FABRIC USING PMMA/PS BASED CLAD-STRIPPED PLASTIC OPTICAL FIBER Download Article

    Sun Hee Moon and InHwan Sul
    • Article Type: Research Article
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    • Pages (122-125)
    • No of Download = 362

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    Plastic optical fibers (POF) have several advantages over the conventional glass optical fibers (GOF), such as flexibility and transfer of visible lights. For information delivery, various IT devices can be interconnected into or onto the fabric. For aesthetic value, fabric can be active light emission device using optical fiber. In this work, we propose a light emission fabric which contains optical fiber structure with the external clad layer removed using mechanical or chemical method. POF was embedded into plain weave structure and the light scattering phenomenon was measured quantitatively by specially designed 3D printed jig using google SketchUp software. Various light frequency including 405nm, 455nm, 530nm and 627 nm tested because visible and UV lights were of our concern. Thermal and mechanical force were used for the clad removal respectively and the removal status was measured using microscope. Light scattering was stronger in clad-removed fibers, especially 5 times in 455 nm.

  22. EMISSION FACTORS OF BLACK CARBON (BC) FROM RICE STRAW OPEN BURNING SPECIFIC TO DISTRICT CIANJUR, WEST JAVA, INDONESIA Download Article

    Hafidawati, Puji Lestari and Asep Sofyan
    • Article Type: Research Article
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    • Pages (126-130)
    • No of Download = 458

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    Open burning of rice straw, common practice in Cianjur, West Java, to eliminate rice residues after harvesting. However, the common practice of post-harvest burning of rice straw emits particulate material , greenhouse gases, and short lived climate force to the atmosphere. Open burning of rice residues in the field releases a large amount of Black Carbon (BC). In this context, this work aims to determine rice straw burning emission factors for Black Carbon on particulate material smaller than 2.5 μm (PM 2.5) in the field open burning in Districts Cugenang, Cianjur, West Java, Indonesia. Samples of airborne particulate matter (PM2.5) from open burning of rice straw were collected at seven locations in District Cugenang for eight varities of rice straw, from June through October 2015. The samples were collected using a minivol air sampler. Black carbon was analyzed using an EEL smoke stain reflectometer. Excess mixing ratios for CO2, CO, BC in PM2.5 were measured, allowing the estimation of their respective emission factors. The average of BC emission factor for eights varieties (Mekongga, Hibrida, Ciherang, Inpari, Cintanur, Sarangue, Inul dan Pandan wangi ) was 0.501, 0.817, 0.749, 0.973, 0.794, 0.847, 0.928, 1.099 g/kg respectively. Average estimated values for emission factors (g kg−1 of burned dry biomass) were 0.939 ±0.417 for BC in PM2.5. These emission factors presented provide useful information for the development of local emission factors for Black Carbon from open burning of rice straw in Cianjur.

  23. NORMAL RATIO IN MULTIPLE IMPUTATION BASED ON BOOTSTRAPPED SAMPLE FOR RAINFALL DATA WITH MISSINGNESS Download Article

    Siti Nur Zahrah Amin Burhanuddin, Sayang Mohd Deni and Norazan Mohamed Ramli
    • Article Type: Research Article
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    • Pages (131-137)
    • No of Download = 460

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    The existence of missing values in rainfall data series is inevitably affects the quality of the data. This problem will influence the results of analysis and subsequently provide imprecise information to the hydrological and meteorological management. A practical and reliable approach is needed in developing estimation methods to impute the missing values. Single imputation is the most commonly used approach for missing values, but, it encounters with the limitation of not considering the uncertainty and natural variability in missing data imputation. Thus, this study has proposed multiple imputation approach based on bootstrap samples in order to overcome the limitation of single imputation approach. Three normal ratio estimation methods are implemented using the proposed approach. The performances of the estimation methods are evaluated at six different levels of missingness. Complete 40 years daily rainfall data from four meteorology stations were considered for the analysis purpose with Johor Bahru station was selected as the target station. The results of the proposed approach were compared to the results obtained from single imputation approach and the widely known built in software for multiple imputation, Amelia II package, in assessing the performance of proposed approach. The results showed that all estimation methods that implemented using proposed approach provided the most accurate estimation results at all percentages of missingness. This proves the advantage of adaption of variability and uncertainty element in the proposed approach in estimating the missing rainfall data at the area of the current study.

  24. ANALYSIS OF A VERTICAL SEGMENTAL SHAFT USING 2D & 3D FINITE ELEMENT CODES Download Article

    Vasiliki N. Georgiannou, Andreas Serafis and Eleni-Maria Pavlopoulou
    • Article Type: Research Article
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    • Pages (138-146)
    • No of Download = 1540

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    This computational research investigates the method of supporting underground cylindrical openings using prefabricated elements. The “Underpin” method is used to simulate the excavation and support of a vertical cylindrical shaft constructed in dry low cohesion soil layers. The primary objective of this study is to determine the stress distribution around the shaft due to three dimensional loading conditions. To this end the excavation is initially simulated as an axisymmetric problem using the “PLAXIS 2D” finite element program. The aforementioned method of analysis is subsequently verified against the equivalent “PLAXIS 3D” finite element analysis.
    Attention has been directed towards recognising the crucial parameters affecting the analysis. It has been found that the constitutive model adopted to simulate the soil behavior (“Mohr-Coulomb” or “Hardening-Soil” model) is of paramount importance and that the shaft diameter also has some influence. However, variations of the shear strength parameters (c’, φ’) at the soil-structure interface as well as in the value of “Unloading-Reloading Modulus” (Eur) have shown only a minor influence on the results of the analysis.
    Floor uplift due to unloading, the development of an excessive plastic zone around the bottom of the vertical shaft, significant surface settlement around the shaft and most importantly the high values of tangential hoop stresses observed in the circular segmental rings, are the main issues raised in the calculations.