Time filter

Source Type

Hebbale A.M.,Nmam Institute Of Technology | S S.M.,Malnad College of Engineering
Materials Today: Proceedings

In the present work microwave cladding technique was progressed for enhancement of surface properties of high speed steel (SS-304). The experiments were conducted in domestic microwave oven with the help of Al2O3 shield. The clad of thickness, approximately 1mm was developed by microwave exposure at frequency 2.45GHz. The entire setup was exposed to microwave environment for about 1080s. The developed clads were characterized using FE-SEM, EDS, XRD and measurement of Vicker's microhardness. Microstructural study reveals that there is a metallurgical bond with SS-304 substrate & partial diffusion of constituent elements. Chromium was observed segregated around the cell boundaries while iron and nickel were identified inside the cells. © 2015 Elsevier Ltd. Source

Bekal S.,Nmam Institute Of Technology | Bhat N.R.,Srinivasa Institute of Technology
Energy Sources, Part A: Recovery, Utilization and Environmental Effects

The substitution of mineral oil with vegetable oil as a lubricant in a CI engine is explored in this study. The experiments have been conducted with neat pongamia oil, blend of pongamia oil and mineral oil (50% V/V), and neat mineral oil as lubricants; and neat pongamia oil, blends of pongamia oil, and diesel in proportions of 20, 40, and 100, neat pongamia ester, and blends of pongamia ester and diesel in proportions of 20, 40, and 100 as fuel. For various combinations of fuel and lubricant, NOx, smoke, CO, HC, BSEC, EGT, and friction power were compared. It was found that there was no difficulty in operating the engine using the lubricants considered in this work. Further, it was found that the best results were recorded for the fuel-lubricant combination of neat pongamia as both fuel and lubricant. © 2012 Copyright Taylor and Francis Group, LLC. Source

Janaki M.,Vellore Institute of Technology | Prabhu N.,Nmam Institute Of Technology | Thirumalaivasan R.,Vellore Institute of Technology | Kothari D.P.,MVSR Engineering College
International Journal of Electrical Power and Energy Systems

The Voltage Source Converter based HVDC provides asynchronous interconnection between two AC systems. The use of VSC HVDC enables independent control of real and reactive power. Unlike conventional HVDC, the VSC HVDC does not cause Subsynchronous Resonance (SSR) when it is close to turbo-generators. The system strength of long ac transmission line can be enhanced by providing series compensation. However, there is a possibility of SSR interaction with turbine-generator due to the presence of the series capacitor in transmission line and may lead to shaft failure of the turbine-generator. The objective of this paper is to analyze the damping of subsynchronous resonance when the series compensated long AC line and VSC HVDC are originated from the same substation. A simple method for the extraction of subsynchronous component of line current using filter is proposed. The extracted subsynchronous frequency current is injected by the VSC HVDC converter close to the turbine-generator. This suppresses the subsynchronous current flowing through the generator and increases the damping of the system at critical torsional frequencies. This technique is termed as Subsynchronous Current Injection (SSCI). Subsynchronous current injector is designed using D-Q model of VSC HVDC. Genetic Algorithm (GA) is used for tuning the converter controllers and filter parameters. The results show the effectiveness of the proposed subsynchronous current injector in damping of SSR. © 2013 Elsevier Ltd. All rights reserved. Source

Prabhu N.,Nmam Institute Of Technology
Power Systems

Series compensation of long transmission lines is an economic solution to the problem of enhancing power transfer and improving system stability. However, series compensated transmission lines connected to the turbo generator can result in Subsynchronous Resonance (SSR) leading to undamped Subsynchronous Oscillations (SSO). The advent of Flexible AC Transmission System (FACTS) controllers using high power semiconductors has made it possible to apply these controllers in conjunction with fixed series compensation, not only to improve system performance, but also to overcome the problem of SSR. FACTS controllers based on Voltage Source Converter (VSC) are emerging controllers that have several advantages over the conventional ones using thyristors. STATCOM is a shunt FACTS controller suitable for voltage regulation and damping of oscillations. This chapter describes the analysis and simulation of a series compensated system with STATCOM connected at the electrical center of the transmission line. The SSR characteristic of the combined system is discussed. A new technique of SSR damping is presented in which a STATCOM injects subsynchronous current. © 2015 Springer Science+Business Media Singapore. Source

Rajesh Kumar B.,Nmam Institute Of Technology | Vardhan H.,National Institute of Technology Karnataka | Govindaraj M.,National Institute of Technology Karnataka | Vijay G.S.,Manipal University India
International Journal of Rock Mechanics and Mining Sciences

This study aims to predict rock properties using soft computing techniques such as multiple regression, artificial neural network (MLP and RBF) models, taking drill bit speed, penetration rate, drill bit diameter and equivalent sound level produced during drilling as the input parameters. A database of 448 cases were tested for determination of uniaxial compressive strength (UCS), Schmidt rebound number (SRN), dry density (ρ), P-wave velocity (Vp), tensile strength (TS), modulus of elasticity (E) and percentage porosity (n) and the prediction capabilities of the models were then analyzed. Results from the analysis demonstrate that neural network approach is efficient when compared to statistical analysis in predicting rock properties from the sound level produced during drilling. © 2012 Elsevier Ltd. Source

Discover hidden collaborations