Faculty Publications
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Item New manufacturing process of carbon-carbon composites and their mechanical properties(2011) Naik, P.S.; SurendranathanThis paper presents the synthesizing of carbon-carbon (CC) composites by preformed yarn (PY) method, by varying the percentage of carbon fiber volume. The PY used is carbon fiber bundle surrounded by coke and pitch which is enclosed in nylon-6. Three types of samples with fiber weight fractions of 30%, 40% and 50% respectively, are fabricated and tested. In each case, the PY is chopped and filled into a die of required shape and hot pressed at 600°C to get the carbonized composite. To obtain the graphitic structure, the specimen is heat treated at 1800°C followed by soaking for two hours. Further, one cycle pitch impregnation is done by hot isostatic pressing, to eliminate the voids. The characteristics such as hardness, compressive strength and creep, are studied. It is observed that, as the carbon fiber percentage increases the properties also improved, provided sintering is done at fairly higher temperatures. The superiority of the new class of CC composites made by the proposed PY technique over those obtained by the conventional methods is also demonstrated. © 2011 CAFET-INNOVA TECHNICAL SOCIETY.Item Novel hybrid photocatalytic reactor-UF nanocomposite membrane system for bilge water degradation and separation(Royal Society of Chemistry, 2015) Moslehyani, A.; A.F., A.F.; Othman, M.H.D.; Isloor, A.M.This study focuses on the design and performance of a hybrid system consisting of a photocatalytic reactor and ultrafiltration permeation cell. Initially, an ultraviolet (UV) lamp was installed in the photocatalytic reactor to decompose the bilge organic pollutants in the presence of 200 ppm titanium-dioxide (TiO2). Individual hydrocarbon compounds of bilge water samples were identified by gas chromatography-mass spectrometry (GC-MS) analysis. Two types of membrane, which are a pure polyvinylidene fluoride (PVDF) membrane and PVDF/modified halloysite nanotube clay (M-HNTs) nanocomposite membrane were fabricated aiming to enhance the rejection, flux and fouling resistance for full filtration of pollutants from the photocatalytic reactor. The membranes were characterized by Fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). Furthermore, GC-MS analysis showed that, over 90% bilge decomposition occurred by a photocatalytic reaction. The TiO2 cross-over during permeation was detected by using an atomic absorption spectrophotometer (AAS), which proved that, TiO2 rejection was more than 99% for the nanocomposite membrane. A UV- vis spectrophotometer confirmed over 99% rejection of decomposed bilge hydrocarbons via the nanocomposite membrane with 1.0 wt% of M-HNTs incorporated in the PVDF matrix. This journal is © The Royal Society of Chemistry 2015.Item Plant root nodule like nickel-oxide-multi-walled carbon nanotube composites for non-enzymatic glucose sensors(Royal Society of Chemistry, 2015) Prasad, R.; Gorjizadeh, N.; Rajarao, R.; Sahajwalla, V.; Badekai Ramachandra, B.R.Herein, in this work we synthesized plant root nodule like NiO-MWCNT nanocomposites by a simple, rapid and solvent-free method using nickel formate as a precursor. Using a first-principle simulation study the interactions and charge transfer behaviour of the NiO and MWCNT composite is investigated. The as-prepared NiO-MWCNT composite is employed to fabricate a modified non-enzymatic carbon paste electrode (CPE) for glucose sensing. From the electrochemical investigation, the fabricated sensor shows an excellent sensitivity of 6527 ?A mM-1 cm-2 with a detection limit of 19 ?M and a linear response over a range from 0.001 mM to 14 mM of glucose concentrations, at an applied potential of 0.5 V. Importantly the sensor also exhibits greater stability, selectivity and reproducibility. A first principle simulation study shows the differences in charge density and charge transfer behaviour from nanotubes to NiO nanoparticles, which in turn enhances the electro catalytic property of the NiO-MWCNT composite. Hence, these results indicate that the NiO-MWCNT composite is a potential material for non-enzymatic electrochemical glucose sensors. This journal is © The Royal Society of Chemistry.Item Multi-wall carbon nanotube-NiO nanoparticle composite as enzyme-free electrochemical glucose sensor(Elsevier, 2015) Prasad, R.; Badekai Ramachandra, B.R.We report a simple, solvent-free method to decorate multi-walled carbon nanotubes (MWCNTs) with nickel oxide nanoparticles (NiO-NPs). The as prepared NiO-MWCNT composite were characterised by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy. The enzyme-free modified carbon paste electrode (CPE) was fabricated using as-synthesised composite material and investigated for glucose sensing. The 10% NiO-MWCNTs composites sensor showed excellent electro-catalytic activity towards direct glucose oxidation. The sensitivity of this sensor is found to be 1696 ?A mM-1 cm-2 and 122.1 ?A mM-1 cm-2 and the limit of detection (LOD) was found to be 11.04 nM and 31 ?M for the linear response over glucose concentration ranging from 1-200 ?M to 0.5-9.0 mM, respectively. Furthermore, the 10% NiO-MWCNTs sensor also showed excellent anti-interference ability, high stability and good reproducibility. Hence, due to simple method of material preparation, easy sensor fabrication and excellent electro catalytic activity towards glucose oxidation, the 10% NiO-MWCNT/CPE is a potential material for the development of enzyme-free sensor for reliable glucose determination. © 2015 Elsevier B.V. All rights reserved.Item Performance and analysis of temperature dependent multi-walled carbon nanotubes as global interconnects at different technology nodes(Kluwer Academic Publishers barbara.b.bertram@gsk.com, 2015) Sandha, K.; Raj, B.A temperature dependent performance in terms of power delay product (PDP) of multi-walled carbon nanotube (MWCNT) bundle interconnect has been analyzed for temperature range from 200 to 450 K at three different technology nodes viz. 32, 22 and 16nm. A similar analysis is performed for copper interconnect and results are compared with MWCNT bundle interconnect. Comparative results revealed that delay and PDP is increased with rise in temperature ranging from 200 to 450 K. It has also been observed that the temperature dependent MWCNT bundle interconnect gives better performance in terms of delay, power and PDP as compared to copper interconnect for three technology nodes at global interconnect length. © 2015, Springer Science+Business Media New York.Item Influence of temperature on MWCNT bundle, SWCNT bundle and copper interconnects for nanoscaled technology nodes(Springer New York LLC journals@springer-sbm.com, 2015) Sandha, K.; Raj, B.This paper presents the comparative analysis of temperature dependent performance of Multi-walled carbon nanotubes (MWCNT), Single-walled carbon nanotube (SWCNT) and copper interconnects for nanoscaled technology nodes. The temperature dependent impedance circuit model is proposed for MWCNT bundle interconnects. The proposed model for MWCNT bundle shows the various electron–phonon scattering mechanisms dependency as a function of temperature. The performance in terms of propagation delay, power dissipation and power delay product for MWCNT bundle interconnects is simulated on the basis of temperature dependent electrical parameters for global interconnects at three different technology nodes viz. 32, 22 and 16 nm for temperature range 200 to 450 K. A similar analysis is performed for SWCNT bundle and copper interconnects and results are compared with the MWCNT bundle interconnects. The comparative results revealed that the performance of MWCNT bundle interconnects is better than the performance of SWCNT bundle and copper interconnects at different temperature ranging from 200 to 450 K for 32, 22 and 16 nm technology nodes at global interconnects. © 2015, Springer Science+Business Media New York.Item Fabrication of polydopamine functionalized halloysite nanotube/polyetherimide membranes for heavy metal removal(Royal Society of Chemistry, 2016) Hebbar, R.S.; Isloor, A.M.; Kulal, K.; A.F., A.F.Polydopamine modified halloysite nanotubes (HNTs) were synthesised through a one step facile procedure and employed as a well dispersed hydrophilic additive to enhance the filtration properties of polyetherimide (PEI) membranes. The nanocomposite membranes were prepared by an immersion precipitation method with different amounts of modified HNTs (MHNTs) in the casting solution. The good dispersion of MHNTs throughout the membrane matrix was confirmed by elemental mapping analysis. The prepared nanocomposite membranes were extensively studied in terms of their porosity, morphology, membrane hydraulic resistance and hydrophilicity. The permeation experiments showed that the modified membranes exhibited higher water flux than a pristine PEI membrane. The antifouling and anti-biofouling behaviour of the modified membranes was investigated in detail. The results revealed that a membrane with a 3 wt% MHNT dosage showed a higher Fouling Resistance Ratio (FRR) of 74.5% with reversible membrane fouling of 64.3%. Moreover, the membrane showed excellent resistance to microbial growth on the membrane surface. The well performing membrane was subjected to heavy metal ion rejection. Results indicated that membranes had the capacity to adsorb Pb2+ and Cd2+. Overall, PEI-MHNTs nanocomposite membranes could have great potential to improve antifouling, anti-biofouling and filtration properties. © The Royal Society of Chemistry 2016.Item Nickel-oxide multiwall carbon-nanotube/reduced graphene oxide a ternary composite for enzyme-free glucose sensing(Royal Society of Chemistry, 2016) Prasad, R.; Ganesh, V.; Badekai Ramachandra, B.R.We report a solvent-free method of preparation for a NiO-carbon nanotube/graphene ternary composite using nickel formate as a green precursor via a thermal decomposition method. In this ternary composite, NiO with an average particle size of 7 nm is regularly decorated on the surfaces of conductive carbon matrix networks such as MWCNTs and reduced graphene oxide (rGO). Here rGO serves as an ideal support for the uniform distribution of NiO nanoparticles and also functions as an efficient transducer material, whereas, MWCNTs act as a spacer between rGO, which enhances the electrical conductivity and accessibility of the active reaction sites for direct glucose oxidation. The electrochemical performances were evaluated by cyclic voltammetry and amperometric techniques. Under the optimal conditions, the 20 wt% NiO-MWCNT/rGO/GCE exhibits a sensitivity of 4223.3 ?A cm-2 mM-1 and a detection limit of 0.92 ?M over a linear glucose concentration range up to 19 mM. Furthermore, the constructed sensor is effectively employed to detect glucose in real human blood serum samples with adequate results. The modified 20 wt% NiO-MWCNT/rGO/GCE also shows a high sensitivity, greater selectivity, excellent reproducibility and long-term stability. © 2016 The Royal Society of Chemistry.Item Preparation of polysulfone-based PANI-TiO2 nanocomposite hollow fiber membranes for industrial dye rejection applications(Royal Society of Chemistry, 2016) Pereira, V.R.; Isloor, A.M.; Zulhairun, A.K.; Subramaniam, M.N.; Lau, W.J.; A.F., A.F.Polysulfone-based polyaniline-TiO2 containing hollow fiber membranes were prepared via a dry wet spinning method. Polyaniline (PANI) coated TiO2 nanotubes were prepared via chemical oxidative polymerisation and were incorporated into the hollow fiber membranes at different compositions. The hollow fibers were fabricated by varying the air gap distance during the spinning process. The effects of the addition of PANI coated TiO2 and the variation in the air gap distance on membrane performance, such as morphology and the permeability of the membranes, were analysed. The addition of the PANI-TiO2 nanocomposite enhanced the hydrophilicity and antifouling ability of the prepared membranes. The polysulfone hollow fiber membranes were examined for their dye rejection of Reactive Black 5 and Reactive Orange 16. The results indicated that the polysulfone hollow fibers containing 1.0 wt% of PANI-TiO2 fabricated using a 5 cm air gap can be used as a potential candidate for industrial dye rejection and showed a maximum rejection of 81.5% and 96.5% for Reactive Black 5 and Reactive Orange 16, respectively. © 2016 Royal Society of Chemistry.Item Probing the synergism of halloysite nanotubes and electrospinning on crystallinity, polymorphism and piezoelectric performance of poly(vinylidene fluoride)(Royal Society of Chemistry, 2016) Khalifa, M.; Mahendran, A.; Anandhan, S.Poly(vinylidene fluoride) (PVDF) nanofibers have tremendous potential in nano-sensing and energy scavenging applications. In this study, uniaxially aligned nanofibers were developed from halloysite nanotubes (HNT)/PVDF nanocomposite using electrospinning technique. Incorporation of HNT into PVDF not only reduced the diameter of the electrospun nanofibers, but, also improved their morphology. Fourier transform infrared spectroscopy, wide angle X-ray diffraction and differential scanning calorimetry techniques were used to characterize the crystallinity, polymorphism and polymer-filler interaction in the nanocomposite nanofibers. A force sensor was indigenously designed to study the piezoelectric responses of the nanocomposite nanofibers. At 10 wt% of HNT loading, the sensor produced the highest voltage output, which can be ascribed to its highest ?-phase content. Incorporation of HNT and use of electrospinning synergistically enhanced the ?-phase content and hence the piezoelectric behavior of PVDF. Hence, these nanofibers could be promising and prominent materials in sensor and actuator applications. © The Royal Society of Chemistry.