2,553 research outputs found

    Compressibility and Permeability of Solidified Dredged Marine Soils (DMS) with the Addition of Cement and/or Waste Granular Materials (WGM)

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    Dredged marine soils that obtained from dredging work were characterize as geo-waste, which is prone to be dumped rather than to be reused. This type of soil is high in compressibility and low in load bearing capacity. The engineering properties of this soft soil can be improve via soil solidification method. Cement is the common hydraulic binder used in soil solidification, were found to generate the emission of greenhouse gasses (GHG), particularly carbon dioxide (CO2) which also had affected the earth’s atmosphere. Therefore, there has been an increasing interest in using alternate pozzolanic materials such as waste granular materials (WGM) to fully or partially substituted the use of cement in soil solidification. WGM such as coal bottom ash (BA) and palm oil clinker (POC) were opted due to its pozzolanic properties. Prior to the planning of reclamation work using DMS admixed with conventional and/or alternate pozzolanic materials, the consolidation characteristics of the admixed materials must be acknowledged. Hence, the present study will examine the amount of settlement and coefficient of permeability (k) of DMS treated with cement and/or WGM in laboratory-scale experiments. Samples were prepared in various proportion in order to examine the individual effect of the cement and/or alternate pozzolanic materials on compressibility and permeability. For cement-admixed DMS, sample with 20 % of cement have significantly reduced the settlement than untreated and 10 % cemented DMS. For WGM-admixed DMS, the initial void ratio is low as compared to the untreated DMS due to the rearrangement of soil particles, which is densely packed. For cement-WGM-admixed DMS, samples of 15C50BA and 15C50POC displayed significant settlement reduction than 10C100BA, 10C100POC and untreated samples

    Compressibility and permeability of solidified dredged marine soils (DMS) with the addition of cement andor waste granular materials (WGM)

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    Dredged marine soils that obtained from dredging work were characterize as geo-waste, which is prone to be dumped rather than to be reused. This type of soil is high in compressibility and low in load bearing capacity. The engineering properties of this soft soil can be improve via soil solidification method. Cement is the common hydraulic binder used in soil solidification, were found to generate the emission of greenhouse gasses (GHG), particularly carbon dioxide (CO2) which also had affected the earth’s atmosphere. Therefore, there has been an increasing interest in using alternate pozzolanic materials such as waste granular materials (WGM) to fully or partially substituted the use of cement in soil solidification. WGM such as coal bottom ash (BA) and palm oil clinker (POC) were opted due to its pozzolanic properties. Prior to the planning of reclamation work using DMS admixed with conventional and/or alternate pozzolanic materials, the consolidation characteristics of the admixed materials must be acknowledged. Hence, the present study will examine the amount of settlement and coefficient of permeability (k) of DMS treated with cement and/or WGM in laboratory-scale experiments. Samples were prepared in various proportion in order to examine the individual effect of the cement and/or alternate pozzolanic materials on compressibility and permeability. For cement-admixed DMS, sample with 20 % of cement have significantly reduced the settlement than untreated and 10 % cemented DMS. For WGM-admixed DMS, the initial void ratio is low as compared to the untreated DMS due to the rearrangement of soil particles, which is densely packed. For cement-WGM-admixed DMS, samples of 15C50BA and 15C50POC displayed significant settlement reduction than 10C100BA, 10C100POC and untreated samples

    Modeling of Single Bay Precast Residential House Using Ruaumoko 2D Program

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    Precast residential houses are normally constructed in Malaysia using precast shear-key wall panel and precast wall panel are designed using BS8110 where there is no provision for earthquake. However, the safety of this house under moderate and strong earthquake is still questionable. Consequently, the full-scale of residential house are designed, constructed, tested and analyzed under in-plane lateral cyclic loading. Hysteresis loops are plotted based on the experimental work and compared with modeling of hysteresis loops using HYSTERES in RUAUMOKO 2D program. Modified Takeda hysteresis model is chosen to behave a similar pattern with experimental work. This program will display the earthquake excitations, spectral displacements, pseudo spectral acceleration, and deformation shape of the structure. It can be concluded that this building is suffering severe cracks and damage under moderate and severe earthquake

    Multimedia environmental fate and transport model of dichlorodiphenyltrichloroethane (DDT): case study sayong river watershed

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    This study describes the development of a multimedia environmental fate and transport model of dichlorodiphenyltrichloroethane (DDT) at Sayong River Watershed. Based on the latest estimated DDT emission, the DDT concentrations in air, soil, water, and sediment as well as the transfer flux were simulated under the equilibrium and steady-state assumption. Model predictions suggest that soil and sediment was the dominant sink of DDT. The results showed that the model predicted was generally good agreement with field data. Compared with degradation reaction, advection outflow was more important in removal processes of DDT. Sensitivities of the model estimates to input parameters were tested. The result showed that vapour pressure (Ps), chemical solubility (Cs), and absolute temperature (T) of DDT were the most influential parameters for the model output. The model output–concentrations of DDT in multimedia environment is very important as it can be used in future for human exposure and risk assessment of organochlorine pesticides (OCPs) at Sayong River Basin

    Bird Communities and Feeding Guilds From Three Land Use Types in Kerian River Basin, Perak

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    The objectives of this study were to determine the current bird species present in the study areas and to analyze variation of feeding guilds in different habitat types. Point count and mist-netting methods were used for bird census in SF and OP, while only point count method was used in PF. Feeding guilds were determined for each species recorded. A total of 183 species representing 49 families were recorded at all study sites. Secondary forest scored 106 species, followed by PF with 70 species and OP with 58 species. The highest abundance of bird families observed in SF was Pycnonotidae (26.65%), Hemiprocnidae (19.77%) and Muscicapidae (7.10%); in OP, Pycnonotidae (21.59%), Muscicapidae (19.12%) and Sturnidae (17.95%); in PF, Ardeidae (29.09%), Sturnidae (10.15%) and Hirundinidae (7.86%). Alternative hypothesis established that the abundance of species is different across habitat types, F(2,105) = 99.83, p < 0.05. Eight feeding guilds were identified in paddy field and seven in both secondary forest and oil palm plantation. If forests were converted to OP feeding guild could possibly change with a decreased in insectivore, insectivore-frugivore, insectivore-nectarivore and frugivore species; and increased in carnivore, grainivore and omnivore species. If forests were converted to PF feeding guild could possibly change with a decreased in insectivore, insectivore-frugivore and frugivore species; and increased in carnivore, insectivorenectarivore, insectivore-grainivore, grainivore and omnivore species. Comparison between SF and OP with Mann-Whitney U-test showed significant differences in six feeding guilds, including insectivore, insectivore-frugivore, insectivore-nectarivore, frugivore, grainivore and omnivore. Comparison between SF and PF showed significant differences in five feeding guilds, comprising of carnivore, insectivore-grainivore, frugivore, grainivore and omnivore. Comparison between OP and PF showed all feeding guilds to be significantly different. Complex vegetation in forestoffers more niches, with higher plant and insect diversity to support more bird species. In contrast, PF, a temporary wetland, support predominantly various waterbirds and migratory species

    Performance evaluation of VLC system using new modulation approach

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    We propose a modified OFDM modulation based on multiband scheme for visible light communications (VLC) system. The method called catenated-OFDM VLC system can efficiently boost the propagation distance and combat multipath induced the inter symbol interference and inter carrier interference. Design parameters such as number of optical bands, input power, distance and data rate are varied to see their effect on the system performances. Simulation analysis is done using Optisys software Ver. 11.0. The results show that the proposed system offers a good performance at longer transmission distance of 12 m for input power of 2 dBm in case of Band=3 with 10 Gbps data rate. BER curves also indicates that the proposed system can be operated at very high data rate of 15 Gbps. This exhibits the ability of the proposed system to be one of the candidate for future optical wireless communication system

    Characterizations of Biocompatible and Bioactive Hydroxyapatite Particles

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    Mathematics is a beautiful subject with logic applications. However,the most common gene vectors used are virus based (viral gene vectors).These possess high immunological risk, so a non-viral gene vector maybepreferable. Nanocrystalline hydroxyapatite, HAp [Ca10(PO4)6(OH)2]is an example of a possible non-viral gene vector. This is due to its goodbiocompatibility, bioactivity and proven results as a non-viral gene vector.The HAp particles produced in this study was by the sol-gel methodand the processing conditions were varied in terms of the processingtemperatures (20oC, 30oC or 40oC) and the stirring rates (200 rpm, 400rpm or 600 rpm). The particles formed from all of the processing conditionswere systematically characterized and compared to each other. Thecharacterizations performed were FTIR, for identifying functional groups,XRD for phase composition, crystallinity and particle size estimation(by applying Scherrer’s formula) and SEM for surface morphology.Thecharacterizations data obtained showed that the functional groups, phasecomposition, crystallinity and surface morphology were similar for all ofthe samples, the only difference being on the calculated particle size. It alsoshowed that, at a lower processing temperature and higher stirring rate,smaller particle sizes were formed

    CONCENTRIC TUBE-FOULING RIG FOR INVESTIGATION OF FOULING DEPOSIT FORMATION FROM PASTEURISER OF VISCOUS FOOD LIQUID

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    This paper reports the work on developing concentric tube-fouling rig, a new fouling deposit monitoring device. This device can detect and quantify the level of fouling deposit formation. It can also functioning as sampler for fouling deposit study, which can be attached at any food processing equipment. The design is initiated with conceptual design. The rig is designed with inner diameter of 7 cm and with tube length of 37 cm. A spiral insert with 34.5 cm length and with 5.4 cm diameter is fitted inside the tube to ensure the fluid flows around the tube. In this work, the rig is attached to the lab-scale concentric tube-pasteurizer to test its effectiveness and to collect a fouling sample after pasteurization of pink guava puree. Temperature changes are recorded during the pasteurization and the data is used to plot the heat transfer profile. Thickness of the fouling deposit is also measured. The trends for thickness, heat resistance profile and heat transfer profile for concentric tube-fouling rig matched the trends obtained from lab-scale concentric tube-pasteurizer very well. The findings from this work have shown a good potential of this rig however there is a limitation with spiral insert, which is discussed in this paper

    Flow analysis of piston head geometry for direct injection spark ignition engine

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    Constructors of gasoline engines face higher and higher requirements as regards to ecological issues, and increase in engine efficiency at simultaneous decrease in fuel consumption. Satisfying these requirements is possible by the recognition of the phenomena occurred inside engine cylinder, the choice of suitable optimal parameters of fuel injection process, and the determination of geometrical shapes of the combustion chamber and piston head. The aim of this study is to simulate flow in Fuel Direct-Injection engine with different geometrical shapes of piston head. Designing piston head shapes was done by referring to existing motorcycle, Demak 200cc-single cylinder using SolidWork and ANSYS software. The parameter investigated are shallow and deep bowl design of piston head. In term of fuel distribution throughout the combustion chamber, engine model that has deeper bowl (Model 2) shows better fuel distribution than model of shallow bowl as it manages to direct the fuel injected towards the location of spark plug. Total kinetic energy of Model 2 is about 20% higher than Model 1. Therefore, engine with deeper bowl is chose as the best model between the two models as it can create a richer mixture around the spark plug
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