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Al(OH)3 from different sources has been used as supports for a mixture of Fe/Co salts and employed in the synthesis of Multiwall Carbon nanotubes by Catalytic Chemical Vapour Deposition method. These supported-catalysts have been characterized by Scanning Electron Microscopy, Powdered X-ray diffraction, and Thermo gravimetric studies. Surface area was determined by N2 adsorption technique. Carbon nanotubes synthesis reactions have been conducted at 700 °C using acetylene as the hydrocarbon source in N2 atmosphere. The quality and quantity of Multiwall carbon nanotubes depend not only on the carbon source, the textural & structural properties of the support and also their interactions with the active components available on the surface. © 2012 VBRI Press. Source

Narasimha K.R.,Center for emerging technologies | Sridhara S.N.,School of Advanced Engineering Studies | Seetharamu K.N.,PES Institute of Technology
International Journal of Numerical Methods for Heat and Fluid Flow | Year: 2010

Purpose: The purpose of this paper is to present a numerical investigation on pulsating heat pipe (PHP) to study the slug velocities as a function of various parameters. Design/methodology/approach: The governing equation of PHP is solved using explicit embedded Runge-Kutta method, the Dormand-Prince pair in conjunction with MATLAB with the nomenclature 45 for the determination of displacement and the velocity of the slug. Findings: The results show that lower fill ratio, higher diameter, higher operating temperature and higher temperature difference between evaporator and condenser for a given working fluid results in higher slug velocities, indicating higher momentum transfer and hence better heat transport. Research limitations/implications: Under steady state conditions, the design of a PHP is facilitated through the introduction of non-dimensional numbers. Originality/value: The displacement and slug velocities for additional working fluids, namely ethanol and methanol, are determined for the first time. The behaviour of non-dimensional numbers, i.e. Poiseuille number, capillary number and Eckert number in a PHP as a function of various parameters have been studied for the first time. © Emerald Group Publishing Limited. Source

Han S.J.,University of Ulsan | Lee H.-I.,University of Ulsan | Jeong H.M.,University of Ulsan | Kim B.K.,Pusan National University | And 2 more authors.
Journal of Macromolecular Science, Part B: Physics | Year: 2014

Graphene, prepared by the thermal reduction of graphite oxide (GO), was modified with stearic acid to enhance its lipophilicity. A novel method, using the intrinsic epoxy groups on the graphene, was utilized for reaction with stearic acid to minimize the negative impact of the normal functionalization method on the π-electronic system of graphene. Gravimetric analysis, thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS) showed that the stearic acid was effectively attached to the graphene. In addition, Raman spectroscopy and electric conductivity of the graphene showed that this novel modification method, utilizing intrinsic defects, did not damage the π-electronic system of the sp2 bonded carbons. The dispersion of graphene in a low density polyethylene (LDPE) matrix was enhanced; consequently, the reinforcing effect in tensile testing was improved by the lipophilic modification. The crystallization behavior observed by differential scanning calorimetry (DSC) showed that the crystallization of LDPE was hindered by dispersed graphene, more evidently when dispersed uniformly. © 2014 Taylor & Francis Group, LLC. Source

Freskos J.N.,Mallinckrodt Pharmaceuticals | Asmelash B.,Mallinckrodt Pharmaceuticals | Gaston K.R.,Mallinckrodt Pharmaceuticals | Gaston K.R.,Monsanto Corporation | And 8 more authors.
Bioorganic and Medicinal Chemistry Letters | Year: 2013

We describe the synthesis, MMP-2 and 9 potency, and in vitro evaluation of a series of α-sulfone hydroxmate MMP inhibitors conjugated to a series of dyes with different absorption/emission lamina maxima's that can be used to visualize tumors. © 2013 Elsevier Ltd. All rights reserved. Source

Janardhana V.,Birla Institute of Technology | Pamidighantam S.,Center for emerging technologies | Chattoraj N.,Birla Institute of Technology | Roy J.S.,KIIT University | And 2 more authors.
Progress in Electromagnetics Research Letters | Year: 2011

In this paper, a surface micromachined microwave tunable low pass filter, consisting of tunable shunt capacitors and series inductors, has been realized. The filter exhibits insertion loss of less than 1 dB (up to 10 GHz), stop band attenuation of 20 dB at 20 GHz, and cut-off frequency is changed to 8 GHz with the application of DC actuation voltage in the structure. The filter has an overall dimension of 5:5mm×2 mm. The characteristics of tunable filter are investigated with and without packaging. Source

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