69 research outputs found

    Water absorption behaviour of epoxy/acrylated epoxidized palm oil (AEPO) reinforced hybrid kenaf/glass fiber montmorillonite (HMT) composites

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    The use of fiber-reinforced vegetable oil - polymer composites has increased in various technical fields. However, the long-term operating performance of these materials is still not well understood, limiting the development of these composites. In this study, the water absorption performance of hybrid composites, which consist of kenaf fiber and glass fiber as reinforcement, epoxy resin and acrylated epoxidized palm oil (AEPO) as a matrix, and montmorillonite (MMT) nano clays as a filler was evaluated with the function of different fibers layering order. The hand lay-up method is used to produce the composites with the variable number of kenaf fibers and glass fibers layer sequences. The water absorption kinetics of epoxy/AEPO reinforced hybrid kenaf/glass fiber-filled MMT composites are described in this paper. It has been observed that the water absorption rate of the composites depends on the fiber layering sequences. The alternative sequence of Glass-Kenaf-Kenaf-Glass and Kenaf-Glass-Kenaf-Glass composites layers exhibited the lowest moisture absorption rates of 7.61% and 7.63%, respectively

    Modulation of Sn concentration in ZnO nanorod array: intensification on the conductivity and humidity sensing properties

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    Tin (Sn)-doped zinc oxide (ZnO) nanorod arrays (TZO) were synthesized onto aluminum-doped ZnO-coated glass substrate via a facile sonicated sol–gel immersion method for humidity sensor applications. These nanorod arrays were grown at different Sn concentrations ranging from 0.6 to 3 at.%. X-ray diffraction patterns showed that the deposited TZO arrays exhibited a wurtzite structure. The stress/strain condition of the ZnO film metamorphosed from tensile strain/compressive stress to compressive strain/tensile stress when the Sn concentrations increased. Results indicated that 1 at.% Sn doping of TZO, which has the lowest tensile stress of 0.14 GPa, generated the highest conductivity of 1.31 S cm− 1. In addition, 1 at.% Sn doping of TZO possessed superior sensitivity to a humidity of 3.36. These results revealed that the optimum performance of a humidity-sensing device can be obtained mainly by controlling the amount of extrinsic element in a ZnO film

    A systematic review, meta-analysis, and meta-regression of the impact of diurnal intermittent fasting during Ramadan on body weight in healthy subjects aged 16 years and above

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    The Pictorial Fit-Frail Scale: developing a visual scale to assess frailty

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    Background: Standardized frailty assessments are needed for early identification and treatment. We aimed to develop a frailty scale using visual images, the Pictorial Fit-Frail Scale (PFFS), and to examine its feasibility and content validity. Methods: In Phase 1, a multidisciplinary team identified domains for measurement, operationalized impairment levels, and re-viewed visual languages for the scale. In Phase 2, feedback was sought from health professionals and the general public. In Phase 3, 366 participants completed preliminary testing on the revised draft, including 162 UK paramedics, and rated the scale on feasibility and usability. In Phase 4, following translation into Malay, the final prototype was tested in 95 participants in Peninsular Malaysia and Borneo. Results: The final scale incorporated 14 domains, each conceptualized with 3–6 response levels. All domains were rated as “understood well” by most participants (range 64–94%). Percentage agreement with positive statements regarding appearance, feasibility, and usefulness ranged from 66% to 95%. Overall feedback from health-care professionals supported its content validity. Conclusions: The PFFS is comprehensive, feasible, and appears generalizable across countries, and has face and content validity. Investigation into the reliability and predictive validity of the scale is currently underway

    Hydrogen and Carbon Nanotubes from Pyrolysis-Catalysis of Waste Plastics: A Review

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    More than 27 million tonnes of waste plastics are generated in Europe each year representing a considerable potential resource. There has been extensive research into the production of liquid fuels and aromatic chemicals from pyrolysis-catalysis of waste plastics. However, there is less work on the production of hydrogen from waste plastics via pyrolysis coupled with catalytic steam reforming. In this paper, the different reactor designs used for hydrogen production from waste plastics are considered and the influence of different catalysts and process parameters on the yield of hydrogen from different types of waste plastics are reviewed. Waste plastics have also been investigated as a source of hydrocarbons for the generation of carbon nanotubes via the chemical vapour deposition route. The influences on the yield and quality of carbon nanotubes derived from waste plastics are reviewed in relation to the reactor designs used for production, catalyst type used for carbon nanotube growth and the influence of operational parameters
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