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Experimental And Numerical Investigation Of Heat Transfer In Cnt Nanofluids May 2015

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 …


Electrical Conductivity And Transport Properties Of Gold Decorated Amorphous Carbon Nanotubes/Epoxy Composites Jan 2015

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 Jan 2015

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 …


Nanomaterial-Mediated Biosensors For Monitoring Glucose, Eric S. Mclamore, Masashige Taguchi, Andre Ptitsyn, Jonathan C. Claussen Jan 2014

Nanomaterial-Mediated Biosensors For Monitoring Glucose, Eric S. Mclamore, Masashige Taguchi, Andre Ptitsyn, Jonathan C. Claussen

Jonathan C. Claussen

Real-time monitoring of physiological glucose transport is crucial for gaining new understanding of diabetes. Many techniques and equipment currently exist for measuring glucose, but these techniques are limited by complexity of the measurement, requirement of bulky equipment, and low temporal/spatial resolution. The development of various types of biosensors (eg, electrochemical, optical sensors) for laboratory and/or clinical applications will provide new insights into the cause(s) and possible treatments of diabetes. State-of-the-art biosensors are improved by incorporating catalytic nanomaterials such as carbon nanotubes, graphene, electrospun nanofibers, and quantum dots. These nanomaterials greatly enhance biosensor performance, namely sensitivity, response time, and limit of …


Nanoenabled Microelectromechanical Sensor For Volatile Organic Chemical Detection, Chiara Zuniga, Matteo Rinaldi, Samuel M. Khamis, A. T. Johnson, Gianluca Piazza Feb 2013

Nanoenabled Microelectromechanical Sensor For Volatile Organic Chemical Detection, Chiara Zuniga, Matteo Rinaldi, Samuel M. Khamis, A. T. Johnson, Gianluca Piazza

Matteo Rinaldi

A nanoenabled gravimetric chemical sensor prototype based on the large scale integration of single-stranded DNA (ss-DNA) decorated single-walled carbon nanotubes (SWNTs) as nanofunctionalization layer for aluminum nitride contour-mode resonant microelectromechanical (MEM) gravimetric sensors has been demonstrated. The capability of two distinct single strands of DNA bound to SWNTs to enhance differently the adsorption of volatile organic compounds such as dinitroluene (simulant for explosive vapor) and dymethyl-methylphosphonate (simulant for nerve agent sarin) has been verified experimentally. Different levels of sensitivity (17.3 and 28 KHz µm^2/fg) due to separate frequencies of operation (287 and 450 MHz) on the same die have also …


Dna-Decorated Carbon Nanotubes As Sensitive Layer For Aln Contour-Mode Resonant-Mems Gravimetric Sensor, Chiara Zuniga, Matteo Rinaldi, Samuel M. Khamis, Timothy S. Jones, A T. Johnson, Gianluca Piazza Jun 2009

Dna-Decorated Carbon Nanotubes As Sensitive Layer For Aln Contour-Mode Resonant-Mems Gravimetric Sensor, Chiara Zuniga, Matteo Rinaldi, Samuel M. Khamis, Timothy S. Jones, A T. Johnson, Gianluca Piazza

Matteo Rinaldi

In this work a nano-enabled gravimetric chemical sensor prototype based on single-stranded DNA (ss-DNA) decorated single-walled carbon nanotubes (SWNT) as nano-functionalization layer for Aluminun Nitride (AIN) contour-mode resonant-MEMS gravimetric sensors has been demonstrated. Two resonators fabricated on the same silicon chip and operating at different resonance frequencies, 287 and 450 MHz, were functionalized with this novel bio-coating layer to experimentally prove the capability of two distinct single strands of DNA bound to SWNT to enhance differently the adsorption of volatile organic compounds such as dinitroluene (DNT, simulant for explosive vapor) and dymethyl-methylphosphonate (DMMP, a simulant for nerve agent sarin). The …


Nanoenabled Microelectromechanical Sensor For Volatile Organic Chemical Detection, Chiara Zuniga, Matteo Rinaldi, Samuel M. Khamis, A. T. Johnson, Gianluca Piazza Jun 2009

Nanoenabled Microelectromechanical Sensor For Volatile Organic Chemical Detection, Chiara Zuniga, Matteo Rinaldi, Samuel M. Khamis, A. T. Johnson, Gianluca Piazza

Matteo Rinaldi

A nanoenabled gravimetric chemical sensor prototype based on the large scale integration of single-stranded DNA (ss-DNA) decorated single-walled carbon nanotubes (SWNTs) as nanofunctionalization layer for aluminum nitride contour-mode resonant microelectromechanical (MEM) gravimetric sensors has been demonstrated. The capability of two distinct single strands of DNA bound to SWNTs to enhance differently the adsorption of volatile organic compounds such as dinitroluene (simulant for explosive vapor) and dymethyl-methylphosphonate (simulant for nerve agent sarin) has been verified experimentally. Different levels of sensitivity (17.3 and 28 KHz µm^2/fg) due to separate frequencies of operation (287 and 450 MHz) on the same die have also …