Ramesh-Babu Adusumalli
Birla Institute of Technology and Science
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Publication
Featured researches published by Ramesh-Babu Adusumalli.
Holzforschung | 2011
Christian Lehringer; Gerald Koch; Ramesh-Babu Adusumalli; William M. Mook; Klaus Richter; Holger Militz
Abstract The white rot fungus Physisporinus vitreus is currently tested for several biotechnological applications such as permeability improvement of refractory wood species or the optimization of the acoustic properties of wood for violins. The enzymatic activity of P. vitreus results in the degradation of pit membranes and simultaneous alterations of the tracheid cell wall structure in wood of Norway spruce [Picea abies (L.) Karst]. By this means, selective delignification and simultaneous degradation occur in the latewood tracheids at short incubation times. To study the delignification of individual cell wall layers in latewood tracheids, cellular UV-microspectrophotometry was applied to wood of Norway spruce that had been incubated for between 3 and 9 weeks. By means of this technique, the progressing delignification was demonstrated in the latewood tracheid secondary walls. Moreover, local delignification in close proximity to hyphal tunneling, cavities, and notches was evident. Additionally, the mechanical changes were measured (a) at the macroscopic level by Brinell hardness test and (b) at the cellular level by nanoindentation. Brinell hardness was significantly reduced with increasing incubation time which was attributed to the partial delignification. Unlike Brinell tests, results from nanoindentation tests did not show a clear effect of fungal activity because of the material heterogeneity and the high spatial resolution of this technique. The present study provides methodological approaches for the investigation of wood-fungus interactions and contributes to a better understanding of the characteristics of wood decay at the subcellular level caused by the white rot fungus P. vitreus. Moreover, it establishes the basis for a subsequent chemical analysis, for which the results will be the topic of a second paper in this series.
Journal of Materials Science | 2012
Rejin Raghavan; Ramesh-Babu Adusumalli; Gerhard Buerki; Silla Hansen; Tanja Zimmermann; Johann Michler
The mechanical integrity of the interface between two adjacent cells in spruce late wood was studied by uniaxial compression of focused ion beam machined micro-pillars of double cell walls (DCW) containing the compound middle lamella (CML). The DCW reveals a lower yield strength and stiffness than the secondary cell wall (S2). Failure occurs by tearing of the interface between the first (S1) and second layers (S2) of the secondary cell wall exposing the internal arrangement of the microfibrils, while the CML remains intact.
Journal of Composite Materials | 2012
Ramesh-Babu Adusumalli; Moritz Reifferscheid; Hedda K. Weber; Thomas Roeder; Herbert Sixta; Wolfgang Gindl
An experimental investigation into the adhesion of regenerated cellulose fiber lyocell, natural cellulose fiber ramie, and E-glass fiber to the polypropylene (PP) and epoxy matrices, by means of the microbond technique, was conducted. Force–displacement plots indicate a brittle failure of the interface, followed by high frictional forces in the PP matrix and low frictional forces in the epoxy matrix. The interfacial shear strength (IFSS) of lyocell–epoxy system was significantly higher than that measured in the lyocell–PP system. Chemical modification of lyocell fiber with maleic anhydride resulted in a two-fold increase in IFSS with PP. Ramie exhibits better adhesion characteristics, due mainly to the rough surface, than lyocell.
Journal of Reinforced Plastics and Composites | 2010
Ramesh-Babu Adusumalli; Hedda K. Weber; Thomas Roeder; Herbert Sixta; Wolfgang Gindl
Microbond technique is used to measure the interfacial shear strength (IFSS) of cellulose fiber-reinforced composites. Critical aspect ratios are provided for a variety of cellulose fiber-polymer matrix systems to avoid the fiber breakage during microbond test. The influence of fiber cross-section and droplet curing condition on the force-displacement curve and the corresponding change of IFSS are discussed for lyocell-polypropylene system. Finally, a relationship between the contact angle of a polymer drop on a fiber and IFSS is established for composite systems involving thermoset and thermoplastic matrices.
Polymer-plastics Technology and Engineering | 2017
S. Aparna; D. Purnima; Ramesh-Babu Adusumalli
ABSTRACT Nylon 6 blends such as polyamide 6/acrylonitrile–butadiene–styrene and polyamide 6/polypropylene are among the commercially successful blends, having varied applications ranging from automobile parts to construction industry. Nylon 6 blends can be made supertough based on other polymers involved. Nylon 6 blends are immiscible, and the use of compatibilizers can increase the interfacial adhesion between the polymers. Amount of compatibilizer plays a key role in defining the size distribution, dispersion, and adhesion between the polymers. In this paper, a detailed review on the compatibilizers used and the effect of compatibilizer on the mechanical and impact properties of the blends has been given. GRAPHICAL ABSTRACT
Fibers and Polymers | 2018
S. Aparna; D. Purnima; Ramesh-Babu Adusumalli
Carbon fiber composites are preferred in transportation sector due to their high specific strength, modulus and resistance to corrosive environments. This paper reports on usage of Polyamide 6 in automobile exterior components by adding 30 % PP, PP-g-MA (Polypropylene-grafted-Maleic anhydride) as a compatibilizer and Short Carbon fibers (SCF) as reinforcement. The effect of compatibilizer on the tensile and impact properties of the composites has been studied. Composite with 3 phr PP-g-MA and 5 wt% SCF revealed highest tensile strength and only 10 % reduction in its value due to water saturation. Microstructure analysis and Grey relational analysis confirmed the experimental results.
Archive | 2017
Ramesh-Babu Adusumalli; Karthik Chethan Venkateshan; Wolfgang Gindl-Altmutter
Cellulose fibres such as flax, hemp, viscose and lyocell were studied with respect to their use as reinforcing agents in composites. Initially, these fibres are subjected to single fibre tensile tests, and their adhesion with polypropylene and epoxy matrices was determined by application of a microbond technique. Unidirectional epoxy composites with fibre rovings and short fibre–epoxy composites with needle punched nonwovens were manufactured by means of compression moulding. Composites were subjected to mechanical vibrations, bending and tensile tests. Interfacial adhesion was also studied at the macro-level by means of double-notch shear test and scanning electron microscopy. Lyocell fibres performed equally well in comparison with natural cellulose fibres when the dimensional variability was taken into consideration, but less well than Glass fibres at both micro- and macro-levels. The low yield strength and high failure strain observed in the stress–strain diagram of lyocell and lyocell–epoxy composites can be the critical parameter in finding new applications for these biodegradable composites.
Korean Journal of Chemical Engineering | 2016
Srikanta Dinda; Nikhil Sainath Reddy Veeram; Ramesh-Babu Adusumalli
Epoxidation of Nahor oil was performed by H2O2 in the presence of acid catalyst at 50 °C. It was possible to obtain around 70% epoxide yield within 8 hrs of reaction. Amberlite IR 120H showed better epoxide yield compared to H2SO4 and Dowex 50 WX8. The performance of carboxylic acids was found to be in the order of formic acid>acetic acid>propanoic acid. The curing of epoxidized nahor oil involved using ethylenediamine (EDA) and diethylenetriamine (DETA). The adhesive property of the cured resins was tested and compared with commercially available glue. The force required to detach the cardboard joint was about 36.3 N for DETA-cured resin.
Polymer | 2008
Wolfgang Gindl; Moritz Reifferscheid; Ramesh-Babu Adusumalli; Hedda K. Weber; Thomas Röder; Herbert Sixta; Thomas Schöberl
Journal of Materials Science | 2010
Ramesh-Babu Adusumalli; William M. Mook; Raphael Passas; P. Schwaller; Johann Michler
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Swiss Federal Laboratories for Materials Science and Technology
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