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Nāmakkal, India

Selvaraj A.,Salem College | Marappan R.,Paavai Engineering College
International Journal of Advanced Manufacturing Technology

This paper deals with the effect of operating parameters on cage slip in cylindrical roller bearing. A cylindrical roller bearing test rig is developed to measure the running speed of bearing elements at various operating conditions. The effect of operating parameters namely shaft speed, radial load, viscosity of lubricating oil, number of rollers, and bearing temperature on cage slip are experimentally obtained. The critical load and magnitude of cage slip for various operating conditions are obtained. The non-dimensional number is derived based on the operating parameters. The region where cage slip occurs is developed from the derived non-dimensional number and the experimental data. The temperature raise is experimentally obtained during slip condition and its effect on viscosity is included for calculations. The frictional forces are experimentally obtained and are compared with the theoretical findings. The significant effect of operating parameters on cage slip of cylindrical roller bearing is discussed based on the experimental findings. © 2010 Springer-Verlag London Limited. Source

Palanisamy P.,Paavai Engineering College | Nirmala S.,Center for Advanced Research
2013 International Conference on Information Communication and Embedded Systems, ICICES 2013

Femtocell has gained considerable attention to provide indoor ubiquitous mobile broadband coverage at higher data rate along with excellent voice service. It is a low power, short range, user installed Home Base Station for connection of personal equipments such as laptops, notepads and mobile phones provided priority for voice service. Operating at licensed spectrum, femtocells are overlaid on the existing macrocell network, forms a two-tier heterogeneous network. Unplanned ad-hoc manner deployment and restricted access mode of femtocells create much stronger and highly variable interference in the two-tier heterogeneous macro-femtocellular networks. The downlink is more critical in terms of femto-macro interference, because it depends on the proximity of victim UE from base station. If the victim is in much close to the aggressor base station, the QoS of victim gets much affected and there is degradation in overall system capacity and greater outage probability. Emerging interactive and content uploading services stress the need for proper femtocell interference management in such two-tier heterogeneous network. This paper presents a comprehensive study on downlink interference scenarios under co-channel deployment and detailed survey on downlink interference management strategies in such networks. It is concluded that intelligent subchannel allocation using cognitive radio concept and transmit beamforming along codebook restriction, macrocell beam subset selection, ICBM, G-ACCS and partial co-channel deployment schemes play significant role on interference management in OFDMA femtocell networks whereas, in CDMA femtocells distributed adaptive power control, joint power control with admission control and IA code assignment strategy can be used for interference management. Issues such as signaling and channel sensing overhead, computational complexity, potential error in the estimation of RB usage and time complexity in channel selection and power allocation are yet to be solved and indicate rich and clear research prospects in interference management of femtocell networks. © 2013 IEEE. Source

Ganesan V.,Indian Institute of Technology Madras | Senthilkumar D.,Salem College | Ramasamy K.K.,Paavai Engineering College
Applied Energy

This paper reports the experimental results of a single cylinder diesel engine regarding performance, combustion and emission characteristics using Mahua (Madhuca indica) biodiesel and its blends in different volumetric proportions with petro-diesel. The thermo-physical properties of various blends selected for investigation have been experimentally measured for better evaluation of the performance characteristics. Tests have been carried out on a four stroke tangentially vertical (TV) single cylinder diesel engine at 1500. rpm using an eddy current dynamometer. The static injection timing employed is 20° bTDC with constant nozzle opening pressure of 250. bar. Selective Catalytic Reduction (SCR) as well as Cold and Hot Exhaust Gas Recirculation (CEGR and HEGR) techniques are employed to study the reduction of NO. x. Results are compared at full load under steady state condition with conventional engine where no reduction techniques are applied. The comparison indicates that the SCR gives substantial reduction in oxides of nitrogen (NO. x) as compared to other technique in a conventional diesel engine fuelled with biodiesel, B100. For B100 with SCR technique, the percentage reduction in NO. x is around 20% as compared to conventional engine. This research has been carried out keeping in mind the energy consumption by pumps coupled to diesel engines for irrigation purpose and locomotive tractors used in developing countries. The research findings show that Mahua biodiesel gives equally good performance and lower emissions which make it a good alternative fuel to operate diesel locomotives as well as irrigation pumps without any engine modification. © 2014 Elsevier Ltd. Source

Rajalaxmi S.,Paavai Engineering College | Nirmala S.,Muthayammal Engineering College
Journal of Digital Imaging

A new filter has been proposed with the aim of eliminating speckle noise from 2D echocardiography images. This speckle noise has to be eliminated to avoid the pseudo prediction of the underlying anatomical facts. The proposed filter uses entropy parameter to measure the disorganized occurrence of noise pixel in each row and column and to increase the image visibility. Straight kernels with 3 pixels each are chosen for the filtering process, and the filter is slided over the image to eliminate speckle. The peak signal-to-noise ratio (PSNR) is obtained in the range of 147 dB, and the root mean square error (RMSE) is very low of approximately 0.15. The proposed filter is implemented on 36 echocardiography images, and the filter has the competence to illuminate the actual anatomical facts without degrading the edges. © 2014, Society for Imaging Informatics in Medicine. Source

Vadivel S.,Paavai Engineering College
Journal of Materials Science: Materials in Electronics

In the present work, magnesium (Mg) doped SnO2 nanocrystalline thin films were synthesized by simple chemical bath deposition technique. The as-deposited films were annealed at 600 °C for 5 h in ambient atmosphere in order to improve crystallinity and structural perfection. The influence of Mg doping on structural, optical, and morphology of thin films was studied by X-ray diffraction (XRD), Raman spectra, UV–Vis Spectra, photoluminescence, and atomic force micrograph images. The XRD measurements showed that films had a tetragonal rutile type structure with P42/mnm symmetry and the results were good in agreement with the standard JCPDS data (card no: 41-1445). The surface roughness has been found to decrease with the increase of the dopant concentration as investigated by atomic force microscopy. The optical band gap energy of pure SnO2 has been found to be in the range of 3.63 eV and it is shifted to 3.42 eV for 10 wt% Mg doping. In the Raman spectrum, two active mode (A2u and Eu) were observed for Mg–SnO2 thin films. The photocatalytic activities of the films were evaluated by degradation of methylene blue rhodamine B in an aqueous solution under ultraviolet light irradiation. The photocatalytic activity of Mg (10 wt%) doped SnO2 film was much higher than that of the pure SnO2. The samples were further characterized by photoluminescence spectra analysis. © 2015, Springer Science+Business Media New York. Source

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