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Secunderabad, India

Rajashekar M.,St Martins Engineering College | Venu Gopala Swamy I.V.,ACE Engineering College | Kumar T.A.,ACE Engineering College
Journal of Theoretical and Applied Information Technology

The aim of this project is to model a six step discontinuous current mode inverter fed to a Permanent Magnet Synchronous Motor (PMSM) drive using MATLAB/SIMULINK. The dq-axis Voltage-Current and Torque relation in terms of machine parameters are used along with a six step 120 degree mode inverter and gate drive using MATLAB/SIMULINK. There is also a provision for easy changes to the machine parameters and gate drive inverter parameters at appropriate places. The various subsystems allow us to change the parameters like power supply data, phase angle advance, PMSM parameters such as stator resistance, inductance, number of poles, rotor magnet constant, Moment of Inertia of motor and damping constant etc. The above model finds its application in power electronics and drives laboratories. Simulation will be done for a phase angle advance of 30° and 45° for a six step discontinuous current mode inverter fed PMSM drive at no load. © 2005 - 2011 JATIT & LLS. All rights reserved. Source

Srikanth D.V.,St Martins Engineering College | Sreenivasa Rao M.S.,JNTUH College of Engineering
Materials Today: Proceedings

Abrasive jet machining also known as micro-abrasive blasting or pencil blasting is a non-traditional machining process in which the metal removal takes place due to high velocity abrasive particles. The abrasive particles are propelled by high velocity carrier gas (commonly air). This process is specially used for edge shapes and intricate shapes. The metal cutting or drilling is performed due to high impact of abrasive particles on the work surface. This machining technology proves good results when tool life is taken into consideration, given the fact that the abrasive material can be reused several times before abrasive particles lose their cutting effect. It is already proved that this technique is effectively adopted for polishing and deburring processes. The present study highlights the influence of different parameters of Abrasive jet machining like Pressure, SOD, Abrasive Flow Rate, on the Metal removal and Kerf width on Ceramic Tiles, the type of abrasive particle used for this experiments is Al2O3. The experiments are conducted according to TAGUCHI method of L9 orthogonal array and RSM, latter compared with the Results of ANOVA using STATGRAPHICS. © 2015 Elsevier Ltd. Source

Mohandas S.,Indian Institute of Horticultural Research | Poovarasan S.,Indian Institute of Horticultural Research | Panneerselvam P.,Indian Institute of Horticultural Research | Saritha B.,Indian Institute of Horticultural Research | And 3 more authors.
Scientia Horticulturae

A total of eight actinomycetes were isolated from Glomus mosseae spores predominant in the rhizosphere of guava (Psidium guajava L. cv Arka Mridula) orchards in Karnataka State, southern India. Five isolates were identified using RNA polymerase β-subunit gene primers as Streptomyces fradiae, S. avermitilis, S. cinnamonensis, Leifsonia poae and Streptomyces canus. All the isolates were tested for beneficial attributes like growth promotion, production of growth hormones like IAA and GA3, phosphate solubilization, siderophore production and antagonistic activity against pathogens including chitinase activity. S. canus recorded increase in guava height and plant dry matter (25.58%, 30.89%) over control followed by S. avermitilis (20.75%, 30%) and S. cinnamonensis (14.05%, 22%) and L. poae (11.09%, 20%) in 10 month-old P. guajava seedlings grown with actinomycetes cultures mixed in coco peat growth medium at 10-8cfug-1 substrate. All the isolates produced growth hormones at varying levels. S. canus produced 10.1μgml-1 of IAA and 12.0μgml-1 of GA3, the highest, compared to others. S. avermitilis, S. canus and L. poae exhibited higher activity of phosphate solubilization, siderophore production and chitin degrading activity out of the five isolates. All the isolates tested in dual culture possessed strong antifungal activity against Fusarium oxysporum and Alternaria solani. The findings from this current study clearly indicated the possibilities of using mycorrhizae associated actinomycetes as bioinoculant for growth promotion, nutrient mobilization and biocontrol agent in guava seedling production. © 2012 Elsevier B.V.. Source

Koppula S.B.,St Martins Engineering College
International Journal of Applied Engineering Research

Literature review revealed that, advanced additive technologies used in today’s high-performance gear oils are capable of inducing the required reactions on the surfaces of gears and bearings, thus providing reliable damage protection even under severe operating conditions. In practice, industrial gears are often operated under lower oil temperatures than would normally be generated in a fully-loaded gearbox. Lower temperatures prevail, for instance, while a gearbox is being taken back into use after prolonged standstill, i. e. during the time it takes for the oil to heat up from ambient temperature to service temperature. Similarly, when a gearbox is being operated below its full load capacity, with reduced speed, or with frequent stop-and-go, the operating temperature of the oil will be lower than it would be under full load. Such applications require gear oils that reliably protect gears and rolling bearings against damage, not only at full load operating temperatures, but also at lower ones. The protection of gears in the gear box against high induced temperature requires careful consideration. Recent research as reported in literature review indicated that, addition of nano particles or particles of nano size (less than 100 micron size) have a great influence on the thermal properties like heat transfer rate, viscosity, friction factor of the lubricant etc and helps in improving the life of the lubricating oil and consequently life of the gear box. An attempt is made in this paper to review the current research on lubricating properties of lubricants and effect of adding nano additives on the performance of lubricants. Present study includes a review of literature on the heat transfer rate, viscosity, friction properties of lubricants etc with and without additives. The major contribution of present work is to review the current state of research in lubricating properties of lubricants used in gear boxes with special referenced to addition of nano particles in the lubricant and to make preliminary investigations on the effect of additives on thermal properties of lubricants used in gear boxes. © Research India Publications. Source

Gowri N.V.,CBIT | Raju M.R.,Jawaharlal Nehru Technological University Kakinada | Singh B.P.,St Martins Engineering College
2015 North American Power Symposium, NAPS 2015

There are several reasons of failure of power transformers in a system. One of the reasons of failure is attributed to the presence and movement of metal particles in oil. These induce partial discharge due to high electrical stresses, in the transformer. In order to theoretically determine the probability of occurrence of partial discharges in a high voltage 220/132 kV autotransformer only HV winding area is modeled. A metal particle of a given size and L/R ratio is introduced at the bottom of HV winding between inner surface of winding and pressboard barrier. Under the influence of oil flow the particle moves randomly within a predefined set of solid angles. During its upward movement the trajectory of the particle is calculated. The particles during their upward movement have demonstrated three different attributes, viz. (a) the particle escapes without striking a high voltage disc. (b) It strikes a disc, however the electric stress induced by the particle at the disc does not exceed threshold voltage for PD to occur and (c) The disc struck by particle provides adequate stress for PD to occur. The present paper deals with the occurrence of PD using probabilistic method for different sizes of wire like particle. © 2015 IEEE. Source

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