Time filter

Source Type

Keerthiprasad K.S.,Nitte Meenakshi Institute of Technology NMIT | Mukunda P.G.,Nitte Meenakshi Institute of Technology NMIT | Majumdar S.,Nitte Meenakshi Institute of Technology NMIT
Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science | Year: 2011

In a centrifugal casting process, the fluid flow eventually determines the quality and characteristics of the final product. It is difficult to study the fluid behavior here because of the opaque nature of melt and mold. In the current investigation, numerical simulations of the flow field and visualization experiments on cold models have been carried out for a centrifugal casting system using horizontal molds and fluids of different viscosities to study the effect of different process variables on the flow pattern. The effects of the thickness of the cylindrical fluid annulus formed inside the mold and the effects of fluid viscosity, diameter, and rotational speed of the mold on the hollow fluid cylinder formation process have been investigated. The numerical simulation results are compared with corresponding data obtained from the cold modeling experiments. The influence of rotational speed in a real-life centrifugal casting system has also been studied using an aluminum-silicon alloy. Cylinders of different thicknesses are cast at different rotational speeds, and the flow patterns observed visually in the actual castings are found to be similar to those recorded in the corresponding cold modeling experiments. Reasonable agreement is observed between the results of numerical simulation and the results of cold modeling experiments with different fluids. The visualization study on the hollow cylinders produced in an actual centrifugal casting process also confirm the conclusions arrived at from the cold modeling experiments and numerical simulation in a qualitative sense. © 2010 The minerals, metals & materials society and ASM international.

Kumar P.J.,University of Shizuoka | Kumar P.J.,Nitte Meenakshi Institute of Technology NMIT | Nishimura K.,University of Shizuoka | Senna M.,University of Shizuoka | And 7 more authors.
RSC Advances | Year: 2016

We present a novel approach to the solid-state synthesis of garnet-type cubic Li7La3Zr2O12 (c-LLZO) nanostructured particles with 1.0 mass% Al at 750 °C within 3 h. In contrast to conventional solid-state processes, a highly reactive precursor was prepared in two steps: (i) by homogenizing the stoichiometric mixture without Li, and (ii) subsequent addition of Li in the form of an ethanolic solution of lithium acetate. The actual composition determined by ICP analysis was Li6.61La3Zr2Al0.13O11.98. Sintering these nanoparticles at 1100 °C for 3 h in air after cold isostatic pressing brought a dense ceramic pellet with a relative density of 90.5%. The corresponding ionic conductivity with Au electrodes was 1.6 × 10-4 S cm-1 at room temperature. To study its electrochemical behavior as an electrolyte, a model cell of Li//(1 M LiPF6 + c-LLZO)//LiCoO2 configuration was constructed. Cyclic voltammetry of the cell delivered one set of redox couple with narrow voltage separation (15 mV) with a Li+ diffusion coefficient at room temperature of about 2 × 10-11 cm2 s-1 at the interface between LiCoO2 and 1 M LiPF6 + c-LLZO. The cell received an average discharge capacity of 64.4, 60.3, 56.1, 51.9 and 46.9 μA h cm-2 μm-1 at discharge rates 0.5C, 1C, 2C, 4C and 6C, respectively. The cell exhibited complete oxidation and reduction reactions with an average initial discharge capacity of about 64 μA h cm-2 μm-1, which is 92.7% of LiCoO2 theoretical value. These observations indicate the applicability of the present c-LLZO as an electrolyte for a solid-state Li-ion battery. © 2016 The Royal Society of Chemistry.

Amitha S.B.,Nitte Meenakshi Institute of Technology NMIT | Chethan K.,University Visvesvaraya College of Engineering | Bhavanishankar S.,University Visvesvaraya College of Engineering | Annapurna B.P.,University Visvesvaraya College of Engineering | And 2 more authors.
International Journal of Earth Sciences and Engineering | Year: 2013

Monolithically built RC wall panels permits for the industrialized construction of a group of integrated buildings using mechanized, rationalized and mass-production procedure. This is a unique, fast and economical technique. Most of the national and international codes comprise of a brief design procedure of this type of construction. Lot of research is being carried out worldwide about the effect of dynamic loads on these structures. In this paper, FE analysis is done on a designed typical monolithic RC wall panel structure for all zones as per Indian code and the results are compared with different international codal provisions and the formulae presented by Saheb & Desayi and Doh & Fragomeni. This paper consists of background, design and construction of monolithic RC wall panel, FE analysis and comparison of results. © 2013 CAFET-INNOVA TECHNICAL SOCIETY.

Madhavi V.,Sri Venkateswara University | Kumar P.J.,Nitte Meenakshi Institute of Technology NMIT | Kondaiah P.,Sri Venkateswara University | Hussain O.M.,Sri Venkateswara University | Uthanna S.,Sri Venkateswara University
Ionics | Year: 2014

Thin films of pure and molybdenum (Mo)-doped tungsten trioxide (WO3) were deposited on indium tin oxide (ITO)-coated glass and Corning glass substrates by RF magnetron sputtering technique. The effect of Mo doping on the structural, morphological, optical and electrochromic properties of WO3 films was studied systematically. The energy dispersive X-ray analysis (EDAX) revealed that the films consist of molybdenum concentrations from 0 to 2 at.%. X-ray diffraction (XRD) studies indicated that with the increase of Mo concentration the structural phase transformation takes place from polycrystalline to amorphous phase. The crystallite size of the films decreased from 24 to 12 nm with increase of doping concentration of Mo in WO3. Scanning electron microscope (SEM) analysis revealed that Mo dopant led to significant changes in the surface morphology of the films. The electrochemical and electrochromic performance of the pure and Mo-doped WO3 were studied. The WO3 films formed with 1.3 at.% Mo dopant concentration exhibited high optical modulation of 44.3 % and coloration efficiency of 42.5 cm2/C. © 2014, Springer-Verlag Berlin Heidelberg.

Lata B.T.,Bangalore University | Sumukha T.V.,Bangalore University | Suhas H.,Bangalore University | Tejaswi V.,National Institute of Technology Karnataka | And 4 more authors.
2015 IEEE International Conference on Signal Processing, Informatics, Communication and Energy Systems, SPICES 2015 | Year: 2015

Congestion control and secure data transfer are the major factors that enhance the efficiency of Service Oriented Wireless Sensor Networks. It is desirable to modify the routing and security schemes adaptively in order to respond effectively to the rapidly changing Network State. Adding more complexities to the routing and security schemes increases the end-to-end delay which is not acceptable in Service Oriented WSNs which are mostly in real time. We propose an algorithm Secure Adaptive Load-Balancing Routing (SALR) protocol, in which the routing decision is taken at every hop considering the unforeseen changes in the network. Multipath selection based on Node Strength is done at every hop to decide the most secure and least congested route. The system predicts the best route rather than running the congestion detection and security schemes repeatedly. Simulation results show that security and latency performance is better than reported protocols. © 2015 IEEE.

Loading Nitte Meenakshi Institute of Technology NMIT collaborators
Loading Nitte Meenakshi Institute of Technology NMIT collaborators