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Electrical Conductivity, Impedance, And Percolation Behavior Of Carbon Nanofiber And Carbon Nanotube Containing Gellan Gum Hydrogels, Holly Warren, Reece Gately, Peter O'Brien, Robert Gorkin Iii, Marc In Het Panhuis
Electrical Conductivity, Impedance, And Percolation Behavior Of Carbon Nanofiber And Carbon Nanotube Containing Gellan Gum Hydrogels, Holly Warren, Reece Gately, Peter O'Brien, Robert Gorkin Iii, Marc In Het Panhuis
Robert Gorkin III
The electrical impedance behavior of gellan gum (GG), GG-carbon nanotube, and GG-carbon nanofiber hydrogel composites is reported. It is demonstrated that the impedance behavior of these gels can be modeled using a Warburg element in series with a resistor. Sonolysis (required to disperse the carbon fillers) does not affect GG hydrogel electrical conductivity (1.2 ± 0.1 mS/cm), but has a detrimental effect on the gel's mechanical characteristics. It was found that the electrical conductivity (evaluated using impedance analysis) increases with increasing volume fraction of the carbon fillers and decreasing water content. For example, carbon nanotube containing hydrogels exhibited a six- …
Experimental And Numerical Investigation Of Heat Transfer In Cnt Nanofluids
Experimental And Numerical Investigation Of Heat Transfer In Cnt Nanofluids
Faculty of Engineering University of Malaya
Nanofluids with their enhanced thermal conductivity are believed to be a promising coolant in heat transfer applications. In this study, carbon nanotube (CNT) nanofluids of 0.01wt%, stabilised by 1.0wt% gum arabic were used as a cooling liquid in a concentric tube laminar flow heat exchanger. The flow rate of cold fluid varied from 10 to 50g/s. Both experimental and numerical simulations were carried out to determine the heat transfer enhancement using CNT nanofluids. Computational fluid dynamics (CFD) simulations were carried out using Fluent v 6.3 by assuming single-phase approximation. Thermal conductivity, density and rheology of the nanofluid were also measured …
Synthesis Of Well-Crystalline Lattice Carbon Nanotubes Via Neutralized Cooling Method
Synthesis Of Well-Crystalline Lattice Carbon Nanotubes Via Neutralized Cooling Method
Faculty of Engineering University of Malaya
In this contribution, vertically aligned carbon nanotubes were synthesized by chemical vapor deposition (CVD). The effects of intrinsic disorders constructed by mobile surface contaminants on the structural perfection of carbon nanotubes (CNTs) were investigated. The results indicated a complete picture on the effect of the involved parameters on the lattice defects of modulated CNTs based on the cooling step. Raman scattering showed that the different cooling methods of the CVD preforms altered the bound complex defects of the structure of the CNTs. Moreover, an array of CNTs was removed from the silicon substrate by applying the neutralized cooling method on …
Electrical Conductivity And Transport Properties Of Gold Decorated Amorphous Carbon Nanotubes/Epoxy Composites
Faculty of Engineering University of Malaya
In this work, chemically synthesized, carboxyl groups functionalized, gold particles hybrid amorphous carbon nanotubes (a-CNT) were characterized. Transmission electron microscopy (TEM) shows that Au/a-CNT hybrid possesses smaller diameter of 10.2 nm than as-synthesized a-CNTs (40 nm). Moreover, even, well-ordered fringes formed on Au/a-CNT hybrid justified successful attachment of Au particles on a-CNT. Impedance plots shows lower resistivity on high Au content's Au/a-CNT hybrid. At the same time, Au/a-CNT hybrids possesses low electrical transference numbers as compared with as-synthesized a-CNTs. Au nanoparticles contribute conducting electrons to Au/a-CNT hybrids and tend to overcome the dominating ionic conduction of a-CNT as Au content …
Functionalization Of Amorphous Carbon Nanotubes For Au Nanoparticles Hybridization
Functionalization Of Amorphous Carbon Nanotubes For Au Nanoparticles Hybridization
Faculty of Engineering University of Malaya
Our study focuses on selection of nitric acid, sulfuric acid, citric acid, and hydrochloric acid as the most suitable oxidation agent for a-CNT. Nitric acid functionalized a-CNT has the highest value of zeta potential -142.9 mV, followed by H2SO4, citric acids, and HCl functionalized samples of -60.3 mV, -15.9 mV, and -3.2 mV, respectively. High values of zeta potential represents surface charges, which refers to carboxyl groups present on tubes' bodies. At the same time, auric chloride (AuCl3) solution treatment was applied on citric acid, nitric acid, hydrochloric acid, and sulfuric acid treated a-CNT at the same condition. Nitric acid …