150 research outputs found

    Characterization of LUSI Mud as Geopolymer Raw Material

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    The mud of mud volcano samples were collected from an eruption site named ‘LUSI’ (Lumpur “mud” –Sidoarjo), East Java, Indonesia for characterization. Analysis showed that, the major constituents of mud are SiO2 and Al2O3 which are higher than those in fly ash. The particle of mud has a flake-shaped particle and the overall particle size is dominated by particles between 2.5μm – 25.0μm. The results of XRD shows that mud of mud volcano have a characteristic of structurally disordered compounds, and a set of peaks corresponding to minor crystalline phases such as quartz, feldspars, and kaolinite. FTIR adsorption bands of the raw material of mud have the chemical bonding between bands 1-5

    Energy efficient partition-lightpath scheme for IP over WDM core networks

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    In this paper, the research focus on the development of energy saving schemes with roots in sleep modes that support the evolution of greener core optical IP networks. The cornerstone of the adopted strategy is partition-lightpath schemes underpinned by the hibernation state implemented through a modification of the intelligent control plane, in particular for transparent network architectures under different scenarios. An enhanced multi-level operational hibernation mode through partition-lightpath was defined including functionality, structure considering its implementation issues. Through the use of appropriate design parameters the impact on blocking probability, wavelengths assignment, LSP connection requests, degree of node connectivity and network utilization can be minimized while also achieving energy savings. Evaluation of this scheme indicates potential reduction in power consumption from 9% up to 17% at the expense of reduced network performance

    Control of animal brucellosis: the Malaysian experience

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    Brucellosis is a zoonotic disease characterized by reproductive failure in animals and undulent fever in humans. In cattle, it is caused by Brucella abortus while in goats by Brucella melitensis, the main cause of brucellosis in humans. Brucellosis in livestock has been associated with importation of animals from breeder herd of unknown disease status. The prevalence of bovine brucellosis Brucella abortus in 2014 ranged between 1% and 2% in Thailand and Indonesia, and 4%–5% in Malaysia and Myanmar. Prevalence of goat brucellosis Brucella melitensis is approximately 1% in Malaysia and Thailand. ‘Test-and-slaughter’ is the general policy against brucellosis adopted by most ASEAN countries to eradicate the disease. Under this program, the Rose Bengal Plate Test (RBPT) is used as the screening test to identify infected farm/herd while the complement fixation test (CFT) is the confirmatory test. The test-and-slaughter eradication strategy that was implemented since 1979 had managed to keep the prevalence rate to less than 5%, from 3.3% in 1979, 0.23% in 1988, 1% in 1998 and 5% in 2016. The test-and-slaughter program seemed effective in reducing the prevalence of brucellosis but was unable to eradicate the disease due to several factors, which include failure to locate and identify the remaining affected animals and to control their movement, importation of breeder animals from non-brucellosis free countries and lack of participation by the farmers following unreliable test results. To support the eradication policy, research activities since 1980s have suggested combinations of serological tests to improve diagnosis while surveillance should be focused on hotspots areas. The prevalence can be further reduced by strictly sourcing breeder animals from brucella-free areas or countries

    Enhancement of Landfill Daily Cover in Minimizing the Migration of Heavy Metals in Landfill Leachate by Using Natural Soil, Pressmud Empty Fruit Bunch (EFB) in PulauBurung Landfill

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    This study emphasizes on the removal of heavy metals in landfill leachate by using natural soil mixed with agricultural wastes. The agricultural wastes used in this study werenatural soil or known as laterite soil, pressmud which is a waste from sugar refinery process and Empty Fruit Bunch (EFB), one of many forms of waste fromoil palm industry. The laterite soil was mixed with these wastes at different percentages of weight ratio namely 50S:40P:10E, 50S:30P:20E, 50S:25P:25E, 50S:10P:40E and 50S:20P:30E. The terms S, P and E each refers to soil, pressmud and empty fruit bunch respectively.Removal efficiency tests were also carried out and the results showed that the mixtures of laterite soil have the ability to remove concentrationsof As2+, Cd2+, Cr2+, Cu2+, Fe2+, Ni2+ and Zn2+between a range of 86% (minimum) and 99% (maximum) compared to removal via soil per se. Ergo, the laterite soil-pressmud-EFB mixtures signify great potential to be made as a daily cover material that minimizes heavy metals migration in landfill leachate, eliminates odor issues and providesadditional protection from further infiltration

    Effect of an in-situ thermal annealing on the structural properties of self-assembled GaSb/GaAs quantum dots

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    In this work, the effect of the application of a thermal annealing on the structural properties of GaSb/GaAs quantum dots (QDs)1 is analyzed by aberration corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM)2 and electron energy loss spectroscopy (EELS)3. Our results show that the GaSb/GaAs QDs are more elongated after the annealing, and that the interfaces are less abrupt due to the Sb diffusion. We have also found a strong reduction in the misfit dislocation density with the annealing. The analysis by EELS of a threading dislocation has shown that the dislocation core is rich in Sb. In addition, the region of the GaAs substrate delimited by the threading dislocation is shown to be Sb-rich as well. An enhanced diffusion of Sb due to a mechanism assisted by the dislocation movement is discussed

    Atomic-column scanning transmission electron microscopy analysis of misfit dislocations in GaSb/GaAs quantum dots

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    The structural quality of GaSb/GaAs quantum dots (QDs) has been analyzed at atomic scale by aberration-corrected high-angle annular dark-field scanning transmission electron microscopy. In particular, we have studied the misfit dislocations that appear because of the high lattice mismatch in the heterostructure. Our results have shown the formation of Lomer dislocations at the interface between the GaSb QDs and the GaAs substrate, but also at the interface with the GaAs capping layer, which is not a frequent observation. The analysis of these dislocations point to the existence of chains of dislocation loops around the QDs. The dislocation core of the observed defects has been characterized, showing that they are reconstructed Lomer dislocations, which have less distortion at the dislocation core in comparison to unreconstructed ones. Strain measurements using geometric phase analysis (GPA) show that these dislocations may not fully relax the strain due to the lattice mismatch in the GaSb QDs

    Grip force measurement of soft- Actuated finger exoskeleton

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    Over recent years, the reseach in the field of soft actuation has been extensively increased for achieving more complex motion path with smooth, high flexible movement and high generated force at minimum operating pressure. This paper presents the study on gripping force capability of soft actuators applied on glove-type finger exoskeleton, developed in motivation to assist individuals having weak finger gripping ability in their rehabilitation exercise towards hand function restoration. The exoskeleton utilizes five cylindrical shaped pneumatic bending actuators developed in the lab, which use fiber reinforcement as a cause of bending motion that drive finger’s flexion movement. Four right-handed healthy volunteers simulated paralysis participated in the study. At 200kPa safe operating pressure, the soft exoskeleton worn by the subjects demonstrates the ability to provide adequate grip force. The grip force generated from exoskeleton worn on passive right hand is 4.66 ± 0.2 N and 3.61± 0.2 N from passive left hand, both higher than the minimum grip forces measured to hold the Hand Dynamometer of 240 g. It shows good potential to be used as a finger rehabilitation assist device

    THE EFFECT OF COSURFACTANT IN CO2 ABSORPTION IN WATER – IN – OIL EMULSION

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    Carbon dioxide is one of the main concern in the environment when it comes to energy usage of fuel, even the fuel is coming from natural gas sources. Apart from endangered the environment, carbon dioxide also affects the caloric value of the natural gas itself. The presence of carbon dioxide as contaminants is a nuisance for oil and gas industry as its capability of forming corrosion in pipeline, thus its removal is vital for this industry. The absorption of carbon dioxide in emulsions would be an effective method to prevent corrosion. This study focused on the effects of cosurfactant, complementing 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) with surfactant which is sorbitan oleate (SPAN 80), on the stability of water-in-oil (W/O) emulsion. This study also investigates the use of blended amines which are methyldiethanolamine (MDEA)/2-amino-2-methyl-1-propanol (AMP) and MDEA as aqueous phase. A modified rotating disk contactor (RDC) was used in absorption process and gas chromatography (GC) was used to determine the amount of the CO2 absorbed. Analysis of carbon dioxide absorption through emulsion indicates that different cosurfactant may change the absorption mechanism

    Effect of Curing Profile on Kaolin-based Geopolymers

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    AbstractDepending on the processing conditions, geopolymers can exhibit a wide variety of properties and characteristics. Curing profile serves as a crucial parameter in synthesis of geopolymers. In this paper, the influence of curing temperature and curing time on the properties of kaolin-based geopolymer was studied. The samples were separated into several curing conditions; including curing at ambient temperature, 40°C, 60°C, 80°C and 100°C for 1 day, and up to 3 days. The compressive strength and SEM analysis of geopolymer products were evaluated. Results showed that curing condition has a significant effect on the mechanical properties of kaolin-based geopolymer. Generally, curing at ambient temperature was not feasible, while increase in temperature favored the strength development. In addition, prolonged curing time improved the geopolymerization process, and led to higher strength gain. However, curing at high temperature for a long period of time caused failure of the sample at a later age

    A wideband dielectric resonator antenna with a cross slot aperture for 5G communications

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    This paper represents design of a wideband Rectangular Dielectric Resonator antenna fed by an aperture coupled technique. A bandwidth of 2.2 GHz has been achieved using a cross slot aperture in a ground plane for Dielectric Resonator Antenna (DRA). The simulated gain value achieved is 6.5 dBi. The Rectangular Dielectric Resonator which has been designed in this paper can be used in 5G application frequency band of 24.25-27.5 GHz. The calculated percentage bandwidth is 15.38%. An optimization of slot dimensions has also mentioned which can help to select a desired impedance match. The measured gain and bandwidth are efficient to use this design for various 5G applications. This unit cell wideband DRA can be used for millimeter wave frequencies of 5G
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