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Aditya G.V.V.,Andhra University | Pujitha B.P.,Andhra University | Babu N.C.,Andhra University | Venkateswarlu P.,PVP Siddhartha Institute of Technology
Korean Journal of Chemical Engineering | Year: 2012

The biosorption of chromium from an aqueous solution onto Erythrina Variegata Orientalis leaf powder was investigated in batch operations. The equilibrium agitation time was 180 min. The extent of chromium biosorption increased from 74.2% to 86.4% with decrease in biosorbent size from 150 to 45 μm for a dosage of 30 g/L. The biosorption decreased from 99.1 (0.45 mg/g) to 45.5% (1.64 mg/g) with an increase in chromium initial concentration (C o) from 22.5 to 180 mg/L. The extent of biosorption was maximum at pH=3. The experimental data were well explained by Langmuir and Redlich-Peterson isotherm models. The biosorption data followed second-order kinetics with a rate constant of 0.078 g/mg-min for 50 g/L of 45 μm size biosorbent. The biosorption was exothermic and feasible. The biosorption was tending towards irreversibility with increasing temperature. © 2011 Korean Institute of Chemical Engineers, Seoul, Korea.

Ravindrababu J.,PVP Siddhartha Institute of Technology | Krishna Rao E.V.,Andhra Loyola Institute of Engineering and Technology
WSEAS Transactions on Communications | Year: 2013

Direct Sequence Code Division Multiple Access (DS-CDMA) system is well known wireless technology. This system suffers from MAI (Multiple Access Interference) caused by Direct Sequence users. Multi-User Detection schemes were introduced to detect the users' data in presence of MAI. In Multi stage Partial parallel interference cancellation (MP-PIC) method complexity is more than multi stage conventional PIC (MC-PIC), but performance is better than MC-PIC. In This paper we proposed multi stage subtractive PIC (MS-PIC). In this method the complexity is less than MP-PIC and performance is slightly less than MP-PIC. Now we proposed one more method that is the combination of partial and subtracting parallel interference cancellation (PS-PIC) in multi stage. This method gives to achieve performance improvement and complexity reduction compared to conventional multistage PIC detector.

Ramesh M.V.,PVP Siddhartha Institute of Technology | Amarnath J.,P.A. College | Kamakshaiah S.,Vignan Institute of Technology and Science | Rao G.S.,Vignan Institute of Technology and Science
Journal of Engineering and Applied Sciences | Year: 2011

This paper presents the fuzzy, PI controller for speed control of BLDC motor. The controller uses three fuzzy logic controllers and three PI controllers. The output of the PI controllers is summed and is given as the input to the current controller. The current controller uses P controller. The mathematical modeling of BLDC motor is also presented. The BLDC motor is fed from the inverter where the rotor position and current controller is the input. The fuzzy logic control is learned continuously and gradually becomes the main effective control. The Simulink software was used to simulate the proposed scheme. The results are obtained for variable load torque. © 2006-2011 Asian Research Publishing Network (ARPN).

Javvaji H.L.,PVP Siddhartha Institute of Technology | Varaja B.B.,Gandhi Institute of Technology and Management
Asia Pacific Conference on Postgraduate Research in Microelectronics and Electronics | Year: 2013

Cascaded multilevel inverters synthesize a medium-voltage output based on a series connection of power cells which use standard low-voltage component configurations. This characteristic allows one to achieve high-quality output voltages and input currents and also outstanding availability due to their intrinsic component redundancy. Due to these features, the cascaded multilevel inverter has been recognized as an important alternative in the medium-voltage inverter market. This paper presents output voltage waveforms and total harmonic distortion (THD) for single phase and three phase cascaded multilevel inverter starting from 5-level to 15-level. Simulation results show that as the number of levels increases the % THD will be reduced. © 2013 IEEE.

Ravindrababu J.,PVP Siddhartha Institute of Technology | Krishna Rao E.V.,Koneru Lakshmaiah College of Engineering | Raja Rao Y.,Rashtreeya Vidyalaya College of Engineering
Wireless Personal Communications | Year: 2014

Multi-stage parallel interference cancellation (PIC) technique gives good performance compared to successive interference cancellation (SIC) method, but biased decision statistic and complexity problems are raised due to imperfect estimation of multiple access interference (MAI) as number of stages increases. partial parallel interference cancellation (PPIC) technique is proposed to cancel the interference partially stage by stage to overcome biased problem. The complexity reduction for PIC detection is based on the convergence nature of interference cancellation which is called the difference PIC (D-PIC) detection technique. In this paper we combine (PPIC and DPIC) these two techniques and propose a multi-stage multi-user (PD-PIC) detector for performance improvement and complexity reduction compared to conventional PIC detector. The performance is degraded as the number of users increases in each technique. © 2014, Springer Science+Business Media New York.

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