54 research outputs found

    Effect of graphene nanoplatelets on flame retardancy and corrosion resistance of epoxy nanocomposite coating

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    Various concentrations of graphene nanoplatelets (GNP) i.e. 0.2, 0.4, 0.6, 0.8 and 1.0 wt. % were incorporated into the epoxy resin by sonication technique and mechanical agitation process. Limiting oxygen index (LOI) test and thermogravimetric analysis (TGA) indicated that the presence of GNP greatly enhanced the flame retardancy properties of the epoxy coating. Salt spray results obtained suggested that the addition of GNP enhanced corrosion performance and reducing the water absorption in comparison with pristine epoxy coating. Adhesion (cross-cut test) revealed that the presence of GNP showed great adhesion to substrates. Incorporation of 0.8 wt. % GNP exhibited the superior anticorrosion performance, great adhesion to subtract, and the lowest water uptake among other samples

    Impacts of Denial-of-Service Attack on Energy Efficiency Pulse Coupled Oscillator

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    The Pulse Coupled Oscillator (PCO) has attracted substantial attention and widely used in wireless sensor networks (WSNs), where it utilizes firefly synchronization to attract mating partners, similar to artificial occurrences that mimic natural phenomena. However, the PCO model might not be applicable for simultaneous transmission and data reception because of energy constraints. Thus, an energy-efficient pulse coupled oscillator (EEPCO) has been proposed, which employs the self-organizing method by combining biologically and non-biologically inspired network systems and has proven to reduce the transmission delay and energy consumption of sensor nodes. However, the EEPCO method has only been experimented in attack-free networks without considering the security elements which may cause malfunctioning and cyber-attacks. This study extended the experiments by testing the method in the presence of denial-of-service (DoS) attacks to investigate the efficiency of EEPCO in attack-based networks. The result shows EEPCO has poor performance in the presence of DoS attacks in terms of data gathering and energy efficiency, which then concludes that the EEPCO is vulnerable in attack-based networks

    Intumescent flame retardant coating based graphene oxide and halloysite nanotubes

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    Epoxy nanocomposites coatings filled with hybrid graphene oxide/halloysites (GO/HNT) based intumescent flame-retardant additives (IFR) have been fabricated and investigated in terms of flame retardancy property, thermal stability, and adhesion strength. The dispersion and interaction of the nanofillers with the matrix were characterized by transmission electron microscopy (TEM) and Fourier transform infrared (FTIR). The synergistic flame-retardant effects of ammonium polyphosphate (APP) on flame retardancy properties and thermal stability were investigated by limiting oxygen index (LOI) and thermogravimetric analysis (TGA), respectively. The result shows that the epoxy coating with hybrid GO/HNT based IFR achieve an LOI of 26 % at 1 phr of APP (EGO0.6H0.3APP1). Meanwhile, the maximum mass loss of the EGO0.6H0.3APP1 coating sample is 391.0 °C which showing an increment by 1.3 % compared with neat epoxy coating, demonstrating excellent thermal stability performance. The char residue also suggests, APP played a synergistic flame-retardant mechanism with a combination of hybrid GO/HNT. The presence of hybrid GO/HNT/IFR considerably enhances adhesion strength between the coating material and metal substrate. The EGO0.6H0.3APP1 showed the maximum LOI value, thermal stability, and adhesion strength among the studied formulations

    EPsmartcoat : Epoxy coating based green nanofillers

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    Bio-based epoxy coating which suitable for wide ranges applications. Affordable and excellent aesthetic value of green coating materials. Benefits of EPsmartcoat : flame retardancy and corrosion-free life (virtual freedom from maintenance and repair)

    Sustainable flame retardant coating based graphene oxide and montmorillonite

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    A comparative study of epoxy filled graphene oxide (GO) and montmorillonite (MMT) and its combination on the flame retardancy and thermal stability of epoxy nanocomposite coatings has been investigated. Limiting oxygen index (LOI) and thermogravimetry analysis (TGA) were carried out to determine the flame retardancy and thermal stability properties and clarifying the correlations between different nanofillers fraction. The result suggests that the formation of an efficient hybrid network evidenced by enhanced the flame retardancy as well as thermal stability performance of epoxy nanocomposite coating. The adhesion tape test results revealed that hybrid nanofillers exerts an obviously synergistic effect, demonstrated by the increased in adhesion strength compare to a single nanofillers. Transmission electron microscopy (TEM) revealed a high dispersion of hybrid GO/MMT due to the physical interaction between the nanofillers and epoxy matrix, responsible for the improved of coating’s performance

    Effect of graphene nanoplatelets on flame retardancy and corrosion resistance of epoxy nanocomposite coating

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    Various concentrations of graphene nanoplatelets (GNP) i.e. 0.2, 0.4, 0.6, 0.8 and 1.0 wt. % were incorporated into the epoxy resin by sonication technique and mechanical agitation process. Limiting oxygen index (LOI) test and thermogravimetric analysis (TGA) indicated that the presence of GNP greatly enhanced the flame retardancy properties of the epoxy coating. Salt spray results obtained suggested that the addition of GNP enhanced corrosion performance and reducing the water absorption in comparison with pristine epoxy coating. Adhesion (cross-cut test) revealed that the presence of GNP showed great adhesion to substrates. Incorporation of 0.8 wt. % GNP exhibited the superior anticorrosion performance, great adhesion to subtract, and the lowest water uptake among other samples

    Synergistic effect of graphene oxide/halloysite in anticorrosion performance and flame retardancy properties of epoxy nanocomposite coating

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    Synergistic effect composed of graphene oxide (GO) and halloysite (HNT) to serve as a promising anticorrosion performance and to enhance flame retardant (FR) properties of epoxy nanocomposite coating (NC) is studied. Using an epoxy as the matrix, GO/epoxy, HNT/epoxy, and hybrid GO/HNT/epoxy samples are prepared and the performance is characterized. The hybridization of GO and HNT leads to improve the barrier properties with EGO0.6H0.3 hybrid sample endows optimum synergistic effect. This is due to the improved state of nanofiller dispersion as well as better interfacial adhesion between the nanofillers and matrix which was confirmed by Transmission Electron microscopy (TEM) images. The Salt Spray test (SST) results corresponding to these effects reaffirmed that the corrosion resistance of the hybrid coatings improved with increasing the inorganic phase content. The thermal stability and flammability properties were investigated using Thermogravimetric Analysis (TGA) and Limiting Oxygen Index (LOI). The results of the LOI test showed that the addition of nanofillers marginally increases the LOI value of the epoxy NC. These results manifestly demonstrated that the formation of an efficient hybrid network slightly enhanced the coating performance through the synergy effect of hybrid nanofillers

    Prospective stem cell lines as in vitro neurodegenerative diseases models for natural product research

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    The use of in vitro model for screening pharmacological compounds or natural products has gained global interest. The choice of cells to be manipulated plays a vital role in coming up with the best-suited model for specific diseases, including neurodegenerative diseases (ND). A good in vitro ND model should provide appropriate morphological and molecular features that mimic ND conditions where it can be used to screen potential properties of natural products in addition to unravelling the molecular mechanisms of ND. In this mini review, we intend to demonstrate two prospective stem cell lines as the potential cell source for in vitro ND model and compare them to the commonly used cells. The common source of cells that have been used as the in vitro ND models is discussed before going into details talking about the two prospective stem cell lines

    Crossing the blood-brain barrier: a review on drug delivery strategies for treatment of the central nervous system diseases

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    Many drugs have been designed to treat diseases of the central nervous system (CNS), especially neurodegenerative diseases. However, the presence of tight junctions at the blood-brain barrier has often compromised the efficiency of drug delivery to target sites in the brain. The principles of drug delivery systems across the blood-brain barrier are dependent on substrate-specific (i.e. protein transport and transcytosis) and non-specific (i.e. transcellular and paracellular) transport pathways, which are crucial factors in attempts to design efficient drug delivery strategies. This review describes how the blood-brain barrier presents the main challenge in delivering drugs to treat brain diseases and discusses the advantages and disadvantages of ongoing neurotherapeutic delivery strategies in overcoming this limitation. In addition, we discuss the application of colloidal carrier systems, particularly nanoparticles, as potential tools for therapy for the CNS diseases
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