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Lal S.,Research and Development Establishment | Kulkarni P.,EKLaT Research | Singh A.,TBRL
Journal of Intelligent Systems | Year: 2012

Network data analysis helps in capturing node usage behavior. Existing algorithms use reduced feature set to manage high runtime complexity. Ignoring features may increase classification errors. This paper presents a model, allowing classification of network traffic, while considering all the relevant features. Learning phase partitions training sample on values of the respective features. This creates equivalence classes related to m features. During classification, each feature value of the test instance results in picking one set from equivalence class generated during learning. Algorithm captures new behavior in semi-supervised incremental learning mode. For problems having m features and n training samples the model has incremental learning complexity of O(m) and average classification complexity is of the order O(m)log 2n) 2). © de Gruyter 2012.

Dahiwale N.,Indian Defence Institute of Advanced Technology | Panigrahi S.,Indian Defence Institute of Advanced Technology | Akella K.,Research and Development Establishment
Journal of Sandwich Structures and Materials | Year: 2015

Sandwich panels made of metal sheets with unfilled cellular cores are found to exhibit lower deflections compared to an equivalent monolithic plate of same metal and similar mass per unit density. The structures having such sandwich panels are suitable under impact loading due to low deflection. However, the process of localized impact on solid structures is quite complicated involving plastic deformation, high strain rates, temperature effect, material erosion, etc. Further, the sandwich panel having triangular corrugated core depends on various design parameters such as thickness of front plate, thickness of back plate, thickness of core, thickness of webs, and angle of web. The influences of these parameters on the structural performance are studied while designing a triangular corrugated core structure for improved ballistic limit for a given mass per unit area. In this research, a numerical analysis of impact of empty triangular corrugated core sandwich panels by ogive nose steel rod projectiles is carried out. Design parameters of the corrugated structure; namely web thickness, core thickness, web angle, front and back plate thickness are varied; and residual velocity of projectile is obtained for each case. Impact at webs resulted in higher projectile retardation and deflection than impact at the base of the prism. For base impacts, improvement in ballistic performance at minimum cost of structural weight can be achieved by increasing web angle or front or back plate thickness, while the same can be achieved for web impacts by increasing web thickness. Since web impacts experience higher penetration resistance than base impacts, designing the panel using optimum design parameters for web impacts is desirable. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav

Singhal A.K.,Indian Institute of Technology Kanpur | Kumar V.,Indian Institute of Technology Kanpur | Ramkumar J.,Indian Institute of Technology Kanpur | Singh R.K.,Research and Development Establishment | Malhotra S.K.,RMK Engineering College
International Journal of Plastics Technology | Year: 2010

The mechanical and tribological behavior of XNBR rubber modified epoxy under dry sliding condition mas investigated using apin-on-disc wear tester at different normal loads. The mechanical properties including tensile strength, tensile modulus, flexural strength and flexural modulus were investigated as per ASTM standards. When modifying epoxy resin with liquid rubber (XNBR), the tensile modulus ofepoxy/XNBR blend decreased by 50% for 2.5% XNBR content, whereas the tensile strength increased by 10.09% at 2.5% loading of XNBR rubber particles. As regards the flexural properties of the epoxy/XNBR blend, both modulus and strength decreased by 27% and 15%, respectively for 2.5% XNBR content. The frictional coefficient and sliding wear rate ofepoxy/XNBR rubber blend were measured against the silicone carbide abrasive paper (grit size-70 y.m) with the sliding distance of 235.5 m for 60 sec. The results showed that XNBR rubber particles increase the wear rate and reduce the coefficient of friction of epoxy/ XNBR blend as compared to neat epoxy resin. The friction coefficient of epoxy/XNBR blends are lower than neat epoxy resin and 2.5% XNBR blend is most effective at 300 g normal load in all compositions. On the other hand, the wear mass loss is higher in epoxy/XNBR blend when compared to unfilled epoxy, hence the specific wear rate is also high in case of epoxy/XNBR blend at same load condition. The 2.5% XNBR modified blend showed the maximum wear mass loss and specific wear rate. The wear rate and mass loss increase with increasing load. © LARPM, Central Institute of Plastics Engineering and Technology, 2009.

Saxena K.,Research and Development Establishment | Bisaria C.S.,Research and Development Establishment | Saxena A.K.,Research and Development Establishment
Applied Organometallic Chemistry | Year: 2010

Silicone core dendrimers bearing terminaldialkoxy andtrialkoxy silane groups were prepared in a three-step synthesis. Initially, the Si-H terminated multifunctional silicone dendrimer, i.e. tetrakis(dimethylsiloxy)silane, was prepared by the reaction of tetraethoxysilane and dimethylethoxysilane. Tetrakis(dimethylsiloxy)silane on reaction with allylglycidylether in the presence of Speier's catalystunderpressure (100 psi) yieldedepoxy- terminateddendrimerin veryhigh yield (95%).Theepoxy-terminated dendrimer was reacted with aminopropylalkoxysilanes to yield the next-generation dendrimer bearing dialkoxy and trialkoxy silane groups. The dendrimers were characterized by the usual physico-chemical techniques, i.e. elemental analysis, FT-IR, 1H, 13C and 29Si NMR. Thermal studies (Thermogravimetric analysis and Thermomechanical analysis) of the alkoxy terminated dendrimers and its cured products were also carried out. Copyright © 2010 JohnWiley & Sons, Ltd.

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