11,791 research outputs found

    Properties of Carbon Black From Jatropha Seed Shell as a Potential Source of Filler Enhancement in Biocomposites

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    The use of biomass as filler in biocomposites are becoming widespread in the present decade because its variety of advantages. Jatropha (jatropha curcas L) seed shell after separated from kernel can be used to produce carbon black because of its higher carbon content, and have the potentiality to use as reinforcement in composites. In this study, carbon black was produced from jatropha seed shell by carbonization in furnace method for 1 hour at 600oC. Thermo gravimetric analysis to analyze seed shell of jatropha as raw material. The morphological properties of the carbon black were analyzed by elemental analysis by X-ray (EDX), SEM, TEM, XRD, SEM, and TEM. It was found that the yield of carbon black was 40% which included 4 different sizes ranging from 70 – 300 mesh in distribution of particle size analysis. Carbon black suggested that it could be a good filler or reinforcement in biocomposite

    Caspase-3 and RasGAP: a stress-sensing survival/demise switch.

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    The final decision on cell fate, survival versus cell death, relies on complex and tightly regulated checkpoint mechanisms. The caspase-3 protease is a predominant player in the execution of apoptosis. However, recent progress has shown that this protease paradoxically can also protect cells from death. Here, we discuss the underappreciated, protective, and prosurvival role of caspase-3 and detail the evidence showing that caspase-3, through differential processing of p120 Ras GTPase-activating protein (RasGAP), can modulate a given set of proteins to generate, depending on the intensity of the input signals, opposite outcomes (survival vs death)

    Reduced graphene oxide-multiwalled carbon nanotubes hybrid film with low Pt loading as counter electrode for improved photovoltaic performance of dye-sensitised solar cells

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    In this work, the role of reduced graphene oxide (rGO) with hyperbranched surfactant and its hybridisation with multiwalled carbon nanotubes (MWCNTs) and platinum (Pt) nanoparticles (NPs) as counter electrode (CE) were investigated to determine the photovoltaic performance of dye-sensitised solar cells (DSSCs). Sodium 1,4-is(neopentyloxy)-3-(neopentyloxycarbonyl)- 1,4-dioxobutane-2-sulphonate (TC14) surfactant was utilised as dispersing and stabilising agent in electrochemical exfoliation to synthesise graphene oxide (GO) as initial solution for rGO production prior to its further hybridisation and fabrication as thin film. A chemical reduction process utilising hydrazine hydrate was conducted to produce rGO due to the low temperature process and water-based GO solution. Subsequently, hybrid solution was prepared by mixing 1 wt% MWCNTs into the produced rGO solution. TC14-rGO and TC14-rGO_MWCNTs hybrid solution were transferred into fluorine-doped tin oxide substrate to fabricate thin film by spraying deposition method. Finally, the CE films were prepared by coating with thin Pt NPs. Photoanode film was prepared by a two-step process: hydrothermal growth method to synthesise titanium dioxide nanowires (TiO2 NWs) and subsequent squeegee method to apply TiO2 NPs. According to solar simulator measurement, the highest energy conversion efficiency (η) was achieved by using CE-based TC14-rGO_MWCNTs/Pt (1.553%), with the highest short current density of 4.424 mA/cm2. The highest η was due to the high conductivity of CE hybrid film and the morphology of fabricated TiO2 NWs/TiO2 NPs. Consequently, the dye adsorption was high, and the photovoltaic performance of DSSCs was increased. This result also showed that rGO and rGO_MWCNTs hybrid can be used as considerable potential candidate materials to replace Pt gradually

    Comparison of Ising magnet on directed versus undirected Erdos-Renyi and scale-free network

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    Scale-free networks are a recently developed approach to model the interactions found in complex natural and man-made systems. Such networks exhibit a power-law distribution of node link (degree) frequencies n(k) in which a small number of highly connected nodes predominate over a much greater number of sparsely connected ones. In contrast, in an Erdos-Renyi network each of N sites is connected to every site with a low probability p (of the orde r of 1/N). Then the number k of neighbors will fluctuate according to a Poisson distribution. One can instead assume that each site selects exactly k neighbors among the other sites. Here we compare in both cases the usual network with the directed network, when site A selects site B as a neighbor, and then B influences A but A does not influence B. As we change from undirected to directed scale-free networks, the spontaneous magnetization vanishes after an equilibration time following an Arrhenius law, while the directed ER networks have a positive Curie temperature.Comment: 10 pages including all figures, for Int. J, Mod. Phys. C 1

    Bond graphs in model matching control

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    Bond graphs are primarily used in the network modeling of lumped parameter physical systems, but controller design with this graphical technique is relatively unexplored. It is shown that bond graphs can be used as a tool for certain model matching control designs. Some basic facts on the nonlinear model matching problem are recalled. The model matching problem is then associated with a particular disturbance decoupling problem, and it is demonstrated that bicausal assignment methods for bond graphs can be applied to solve the disturbance decoupling problem as to meet the model matching objective. The adopted bond graph approach is presented through a detailed example, which shows that the obtained controller induces port-Hamiltonian error dynamics. As a result, the closed loop system has an associated standard bond graph representation, thereby rendering energy shaping and damping injection possible from within a graphical context

    Designing of Collagen Based Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) Scaffolds for Tissue Engineering

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    P(3HB-co-4HB) copolymer was modified using collagen by adapting dual solvent system. The surface properties of samples were characterized by Fourier transforminfrared spectroscopy (FTIR), scanning electron microscopy (SEM), organic elemental analysis (CHN analysis), and water contact angle measurements.The effects of collagen concentration, scaffold thickness, and 4HB molar fraction on the hydrophilicitywere optimized by the Taguchi method.The orthogonal array experiment was conducted to obtain the response for a hydrophilic scaffold. Analysis of variance (ANOVA) was used to determine the significant parameters and determine the optimal level for each parameter. The results also showed that the hydrophilicity of P(3HB-co-4HB)/collagen blend scaffolds increased as the collagen concentration increased up to 15 wt% with a molar fraction of 50mol% at 0.1mm scaffold thickness. The biocompatibility of the P(3HB-co-4HB)/collagen blend surface was evaluated by fibroblast cell (L929) culture.The collagen blend scaffold surfaces showed significant cell adhesion and growth as compared to P(3HB-co-4HB) copolymer scaffolds

    Properties of Carbon Black From Jatropha Seed Shell as a Potential Source of Filler Enhancement in Biocomposites

    Get PDF
    The use of biomass as filler in biocomposites are becoming widespread in the present decade because its variety of advantages. Jatropha (jatropha curcas L) seed shell after separated from kernel can be used to produce carbon black because of its higher carbon content, and have the potentiality to use as reinforcement in composites. In this study, carbon black was produced from jatropha seed shell by carbonization in furnace method for 1 hour at 600oC. Thermogravimetric analysis to analyze seed shell of jatropha as raw material. The morphological properties of the carbon black were analyzed by elemental analysis by X-ray (EDX), SEM, TEM, XRD, SEM, and TEM. It was found that the yield of carbon black was 40% which included 4 different sizes ranging from 70 – 300 mesh in distribution of particle size analysis. Carbon black suggested that it could be a good filler or reinforcement in biocomposites

    DEGRADATION, MECHANO-PHYSICAL, AND MORPHOLOGICAL PROPERTIES OF EMPTY FRUIT BUNCH REINFORCED POLYESTER COMPOSITES

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    This research aims to study the effects of degradation on mechanical, physical, and morphological properties of empty fruit bunch (EFB) fiber- reinforced polyester composites. The unsaturated polyester resin has been used to produce thermoset polymer composites. The reinforcing effect in composites was evaluated at various fiber loadings, including an overall fiber content (by weight) of 20% and 40%. The mechanical (tensile, flexural, and impact) and physical (density, moisture content, and water absorption) properties were studied before and after the samples were buried in the soil for period of 12 months. Scanning electron microscope (SEM) analysis was conducted to visualize the effect of the quality of adhesion between the fibers and matrix. The soil burial investigation results revealed that EFB fiber-polyester composites showed highest degradation percentage as compared to polyester resin and fiberglass

    Natural fiber reinforced poly(vinyl chloride) composites : a review.

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    Materials from renewable resources – also called biomaterials or ‘green’ materials – are presently gaining in importance worldwide. In these times of continuous increases in the price of crude oil and discussion of carbon dioxide (CO2) emissions, conventional plastics have reached a price level and a questionable image which promotes the search of alternatives. Natural fibers are a renewable natural resource and are biodegradable, which is an important characteristic for components that must be disposed of at the end of their useful life. They are recyclable and can be easily converted into thermal energy through combustion without leaving residue. In this study, we will discuss the natural fiber reinforced polyvinyl chloride composites, reinforcing effect, plasticization effect along with modification by coupling agents, properties, and applications based on composite materials. Also, the polyvinyl chloride-based composite materials with specific emphasis on effect of coupling agent, foamed polyvinyl chloride composites, and the effect of natural fiber reinforcement on its material properties will be reviewed. One of the best alternatives is natural fiber reinforced plastics composites. These are composites that are typically filled or reinforced with plant fibers, as well as plastics such as polyvinyl chloride or recently, even bioplastics

    Nonwood-based composites

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    Nonwood fibers are derived mostly from fastgrowing plants. For the past few decades, nonwood plant fibers have received much attention, especially for composite material applications, because of their low cost, low density, high specific strength, good mechanical properties, nonabrasiveness, eco-friendliness, and biodegradability. This article reviews the performance of nonwood fibers found mostly in Asia, as well as issues regarding their bonding. Because various classifications of nonwood exist, this article sorts nonwood fibers based on previous classifications with some modifications, accounting for the availability of these fibers in Asia. The mechanical and physical properties of nonwood-based composites such as fiberboard, particleboard, and veneer-based laminated products also are reviewed and discussed. All fibers demonstrate certain advantages over conventional composites, with some having better mechanical and physical properties. This article also highlights the issues and challenges regarding the use of nonwood fibers as composite materials
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