Pitchan M.K.,Amrita University |
Bhowmik S.,Amrita University |
Balachandran M.,Amrita University |
Abraham M.,Gharda Chemicals Ltd
Composites Part A: Applied Science and Manufacturing | Year: 2016
In this investigation, Polyetherimide (PEI) reinforced with multi-walled carbon nanotube (MWCNT) using novel melt blending technique. Surface of MWCNTs are modified by acid treatment as well as by plasma treatment. PEI nano composites with 2 wt% treated MWCNT shows about 15% improvement in mechanical properties when compared to unfilled PEI. The thermal decomposition kinetics of PEI/MWCNT nano composites has been critically analyzed by using Coats – Redfern model. The increase in activation energy for thermal degradation by 699 kJ/mol for 2 wt% MWCNT implies improvement in the thermal properties of PEI. Studies under Fourier Transform Infrared Spectroscopy (FTIR) and Transmission Electron Microscopy (TEM) depict significant interfacial adhesion with uniform dispersion of MWCNT in polymer matrix due to surface functionalization. 0.5 wt% chemically modified MWCNT shows typical alignment of MWCNT. There is a significant improvement in mechanical properties and thermal properties for surface functionalized MWCNT reinforced. © 2016
Patnaik P.R.,Institute of Chemical Technology |
Patnaik P.R.,Gharda Chemicals Ltd
International Journal Bioautomation | Year: 2015
Microbioreactors offer many advantages over macro-scale reactors for the screening and cultivation of microbial cultures. However, some weaknesses of microbioreactors are yet to be overcome. Optimum mixing under laminar flow, miniaturized on-line measurements and control, integration of upstream and downstream microdevices with the microbioreactor on a single chip, and adequate mathematical models to optimize the performance are some major issues that need to be resolved. Nevertheless, recent research indicates rapidly growing understanding of these problems and it has presented some promising solutions that have led to useful commercial applications. While specialized reviews have covered specific aspects of microbioprocesses exhaustively, the present article reviews microbioreactors per se in a holistic way, analyzing their functions both in a stand-alone setting and in conjunction with other microdevices. We also consider technological developments arising out of the standard microbioreactor and its possible future ramifications.
Patnaik P.R.,Gharda Institute of Technology |
Patnaik P.R.,Gharda Chemicals Ltd
Science and Engineering Ethics | Year: 2015
Along with economic strength, space technology and software expertise, India is also a leading nation in fraudulent scientific research. The problem is worsened by vested interests working in concert for their own benefits. These self-promoting cartels, together with biased evaluation methods and weak penal systems, combine to perpetuate scientific misconduct. Some of these issues are discussed in this commentary, with supporting examples and possible solutions. © 2015 Springer Science+Business Media Dordrecht
Gharda Chemicals Ltd | Date: 2012-09-11
Bijwe J.,Indian Institute of Technology Delhi |
Sharma S.,Indian Institute of Technology Delhi |
Sharma M.,Indian Institute of Technology Delhi |
Sharma M.,Leibniz Institute of Polymer Research |
And 2 more authors.
Wear | Year: 2013
Polyetherketone (PEK) is one of the least explored specialty thermoplastic polymers for its tribo-utility. It exhibits continuous operating temperature up to 280°C and under short-term loads it can function up to 350°C. In literature, hardly anything is reported on the adhesive wear performance of PEK and its composites. Three composites based on PEK containing short fibers of carbon/glass along with various solid lubricants were developed and characterized for thermal and mechanical properties. The tribo-properties were studied under varying loads and speeds by sliding a composites pin against a mild steel disc as a counter face. The studies were focused to examine the role of these ingredients on enhancing pressure × velocity limit (PVlimit), which is an indication of utility of a tribo-polymer in severe operating conditions. The performance assessment was done according to multiple parameters; such as magnitude of coefficient of friction (μ) and its fluctuations with time, PVlimit, compatibility with the counter-face, specific wear rate (K0), etc. Very low K0 (≈10-16m3/Nm), very low μ (0.04-0.20) and very high PVlimit values (>95.2MPam/s) were reported for these composites. White graphite (hexa boron nitride-hBN) proved to be the most efficient solid lubricant. The wear mechanisms using scanning electron microscopy of worn surfaces of pins and discs were studied. It was interesting to observe that glass fibers in the composite showed extremely good performance instead of showing abrasion and high μ. A very different friction and wear mechanism was claimed to be responsible for this. A synergism between lubricating action of two lubricants and layer of molten glass on the disc was the main reason for the enhanced performance. © 2013 Elsevier B.V.