Showing papers by "College of Engineering, Pune published in 2004"

Aminolysis of Poly(Ethylene Terephthalate) Waste for Recovery of Value Added Comonomeric Product

Abstract: Reaction of poly(ethylene terephthalate) waste (PETW) powder with hydrazine monohydrate (HMH) using 0.003 mol lead acetate as a catalyst was carried out in a batch reactor at 339K and at atmospheric pressure. Reactions were undertaken with various particle size ranges from 50–512.5 μm, and reaction time from 30–240 min at the interval of 30 min. Terephthalohydrazide (TPHD) and ethylene glycol (EG) were recovered during aminolysis of PETW. To increase the PETW conversion rate, external catalyst (lead acetate) was introduced during the reaction. The reaction product (TPHD) was deposited on the surface of unreacted PETW that was removed from the surface by introducing dimethyl sulfoxide (DMSO). Moreover, to improve the reaction rate cyclohexylamine (CHA) was introduced during reaction. Aminolysis of PETW was proportional to the reaction time. Depolymerization of PETW was inversely proportional to the particle size of PETW. Analyses of value-added products (TPHD and EG) as well as PETW were undertake...

Performance of line start permanent magnet synchronous motor with single-phase supply system

Abstract: The operation of a three-phase induction motor from a single-phase supply with a capacitor in circuit is well known. While detailed investigations on the performance of the induction motor under such operating conditions are well reported in the literature, no such work is reported for the synchronous motor. The line-start permanent-magnet synchronous motor (LSPMSM) is actively being considered as an energy efficient alternative to the induction motor in general purpose, heavy duty applications. The paper presents an analytical and experimental evaluation on the performance of a three-phase LSPMSM fed from a single-phase supply. This analysis is carried out using symmetrical component theory. A capacitor is connected across two stator phases during starting and running. Estimation of the capacitor value to achieve the desired objectives, such as minimum unbalance, maximum power factor, maximum torque or maximum efficiency, is carried out. Load tests are conducted to validate the simulation results.

Chemical Recycling, Kinetics, and Thermodynamics of Hydrolysis of Poly(ethylene terephthalate) Waste with Nonaqueous Potassium Hydroxide Solution

Abstract: Poly(ethylene terephthalate) (PET) waste was reacted in a batch process with KOH in nonaqueous ehtylene glycol (EG) solution at 100–180°C for 5–140 min to convert them quantitatively into dipotassium terephthalate (K2-TPA) and EG. Particle size of PET, mol/L of KOH, and reaction time required for depolymerization of complete PET were optimized. Dipotassium terephthalate was precipitated into terephthalic acid (TPA) using HCl from the reaction mixture and separated readily. Other product EG, being the same component as nonaqueous solvent (EG) remains in liquid phase. The EG was recovered completely by using the salting-out method. Rate of hydrolysis was significantly accelerated by addition of another additional solvent, tetrahydrofurane (THF) to EG in the atmosphere of cyclohexylamine (CHA). Moreover, to improve the hydrolysis rate, TPA salt deposited from the unreacted PET surface was removed by introduction of dimethylsulfoxide (DMSO). Analyses of monomers (TPA and EG) and PET were undertaken. ...

Speech Recognition for Emotions with Neural Network: A Design Approach

Abstract: Worldwide research is going on to judge the emotional state of a speaker just from the quality of human voice. This paper explores use of supervised neural network to design a classifier that can discriminate between several emotions like happiness, anger, fear, sadness & unemotional state in speech. The results found to be are significant, both in cognitive science and in speech technology. In the current paper, statistics of the pitch like, first and second formants, and Energy and speaking rate are used as relevant features. Different neural network based recognizers are created. Ensembles of such recognizers are used as an important part of decision support system for prioritizing voice messages and assigning a proper agent to response the message. The developed intelligent system can be enhanced to automatically predict and adapt to detect people’s emotional states and also to design emotional robot or computer system.

Microkinetics and mass transfer in aqueous alkaline depolymerization of poly (ethylene terephthalate)

Abstract: Depolymerization of poly (ethylene terephthalate) (PET) in aqueous sodium hydroxide solution was undertaken in a batch process at 90–150°C and 1 atm pressure conditions by varying PET particle size in the range of 50–512.5 µm. Process time also was varied from 10–110 min to describe the effect of particle size of PET and mass transfer time on batch reactor performance. The particle size of PET and operation time required were optimized. Operation products consist of terephthalic acid (TPA) and ethylene glycol (EG) as monomers. A comprehensive model for the depolymerization of PET has been developed, taking into account kinetic data and the diffusion operation for the major by-products as monomers from the waste solid PET powder. The model prediction was undertaken by using our own laboratory data. Experimental data with analysis of depolymerized monomeric products (TPA and EG) of PET show good consistency with model results. Acid value as well as carboxyl-group concentrations of TPA significantly...

RF interference supression using array beamforming

Abstract: In today's EM environment jamming or interference due to own communication sets occurs due to Electromagnetic interference (EMI). In civil communication/ installations and particularly in the armed forces, there has been an ever increasing density and deployment of electronic systems. It is known that the EM spectrum around any platform/ installation is dependent on the radiations emanating from it. Thus, cohabitation of sensitive electronic systems near transmitter aerials has become a major challenge to the designer.

Supersonic Jet Interactions in a Plenum Chamber

Abstract: Understanding the supersonic jet interactions in a plenum chamber is essential for the design of hot launch systems. Static tests were conducted in a small-scale rocket motor ioaded with a typical nitramine propellaiit to produce a nozzle exit Mach number of 3. This supersonic jet is made to interact with plenum chambers having both open and closed sides. The distance between the nozzle exit and the back piate of plenum chamber are varied from 2. 5 to 7. 0 times the nozzle exit diameter. The pressure rise in the plenum chamber was measured using pressure transducers mounted at different locations. The pressure-time data were analysed to obtain an insight into the flow field in the plenum chamber. The maximum pressure exerted on the back piate of plenum chamber is about 25-35 per cent. of the maximum stagnation pressure developed in the rocket motor. Ten static tests were carried out to obtain the effect of axial distance between the nozzle exit and the plenum chamber back piate, and stagnation pressure in the rocket motor on the flow field in the open-sided and closed-sided plenum chambers configurations.