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Lata D.B.,G.H. Raisoni College of Engineering | Baraskar S.S.,Government Polytechnic | Shaw D.,Rtc Institute Of Technology
Biomass Conversion and Biorefinery | Year: 2015

This study presents mathematical modeling of some experimental investigations for different combinations of producer gas and diesel over a wide range of load conditions in dual-fuel operation of a four-cylinder turbocharged diesel engine. Response variables considered in this work were brake thermal efficiency, un-burnt hydrocarbons, carbon monoxide, and oxides of nitrogen. Mathematical models were developed to correlate the input parameters like gaseous fuel substitution and load with response variables. The developed models can be used to predict the responses for different values of gaseous fuel substitution (GFS) and load. Response surface methodology (RSM) has been applied for developing the models using the techniques of design of experiments and multi-linear regression analysis. General factorial design was used to plan the experiments. Second-order response surface models were found to be most suitable in the present work. Analysis of variance (ANOVA) of the experimental results at 95 % confidence level reveals that the developed models are significant. Comparison of experimental output with those predicted by the developed models showed close proximity having high correlation coefficients R2 for the various response variables. © 2014, Springer-Verlag Berlin Heidelberg.

Sharma A.,Birla Institute of Technology | Mishra B.K.,Birla Institute of Technology | Dinesh A.,Birla Institute of Technology | Misra A.,RTC Institute of Technology
International Journal of u- and e- Service, Science and Technology | Year: 2014

Use of high grade electrical energy, generated from fossil fuels, for cooling has increased environmental concerns like global warming and ozone layer depletion. Hence, there is a need to reduce dependence on them and explore potential environmental friendly options. In this aspect, vapor absorption system has scope of utilizing low grade energy source i.e. hot water from solar panel, to generate cooling effect and are environment friendly as no chloro-floro-carbons are used. The most usual combination of absorber refrigerant pair in such system is lithium bromide water (LiBr-H2O), where water vapor is the refrigerant. In present work, a hot water driven, single stage, absorption cooling system, using a lithium bromide water solution, is analyzed for determining the effect of various parameters on coefficient of performance (COP). Four basic stages in the absorption cycle are generation, condensation, evaporation and absorption with ideally no moving part. A configuration of theses four stages, having 5 TR cooling capacity is determined and examined for the variation in COP corresponds to the change in pressure and concentration. The pressure parameter is varied in condenser and evaporator, resulting graph shows that the increment in pressure of evaporator increases the COP whereas increment of pressure in condenser decreases the COP. At lower inlet concentration of LiBr solution to the absorber gives increment in COP. © 2014 SERSC.

Mishra S.K.,Birla Institute of Technology | Sharma V.,Birla Institute of Technology | Misra A.,RTC Institute of Technology
International Journal of Materials Research | Year: 2014

This paper presents some experimental results on the intermittent electromagnetic radiation (EMR) characteristics of sintered aluminium powder preforms under quasi-static compression. The stress level within the gross elastic limit and yielding of the partially compact preforms at which first EMR emission is observed, bears a distinct parabolic relation with the rate of compressive deformation. These observations can be developed into a new technique to detect the compactness of sintered metal powder preforms for industrial components. Further, each successive intermittent EMR emission at all rates of deformation requires increasing incremental strain energy during progressive plastic deformation. The electromagnetic energy release rate decreases sharply as the rate of deformation is increased and then attains a more or less constant value at higher rates of deformation. These results appear significant in understanding the mechanism of plastic deformation in metal powder preforms at the microscopic level, not yet reported in the literature. © Carl Hanser Verlag GmbH & Co. KG.

Misra A.,RTC Institute of Technology | Singh R.,Birla Institute of Technology | Lal S.P.,Birla Institute of Technology
Applied Physics A: Materials Science and Processing | Year: 2015

This paper presents a physical model based on energy approach to explain the intermittent electromagnetic radiation during plastic deformation of metals. The model proposes that during progressive plastic deformation, edge dislocations move through a succession of locking and unlocking stages, amid the pinning barriers such as impurity atoms, dislocation network, etc. and give rise to the intermittent electromagnetic radiation. The net activation energy required for locking, unlocking and intermittent movement of edge dislocations is supplied by externally applied stress in the form of strain energy. The model has been elucidated by considering the stress–strain relationship for strain hardening. The theoretical results are validated by some fresh experiments on commercially pure aluminium and show a close agreement. © 2015 Springer-Verlag Berlin Heidelberg

Singh R.,Birla Institute of Technology | Lal S.P.,Birla Institute of Technology | Misra A.,RTC Institute of Technology
International Journal of Materials Research | Year: 2015

This paper presents experimental results on intermittent electromagnetic radiation during plastic deformation of Cu - Ni alloys under tension and compression modes of deformation. On the basis of the nature of electromagnetic radiation signals, oscillatory or exponential, results show that the compression increases the viscous coefficient of Cu - Ni alloys during plastic deformation. Increasing the percentage of solute atoms in Cu - Ni alloys makes electromagnetic radiation strength higher under tension. The electromagnetic radiation emission occurs at smaller strains under compression showing early onset of plastic deformation. This is attributed to the role of high core region tensile residual stresses in the rolled Cu - Ni alloy specimens in accordance with the Bauschinger effect. The distance between the apexes of the dead metal cones during compression plays a significant role in electromagnetic radiation parameters. The dissociation of edge dislocations into partials and increase in internal stresses with increase in solute percentage in Cu - Ni alloys under compression considerably influences the electromagnetic radiation frequency. © 2015 Carl Hanser Verlag GmbH & Co. KG.

Kothari A.,Clemson University | Kothari A.,Indian Institute of Technology Mandi | Chauhan V.S.,Indian Institute of Technology Mandi | Misra A.,RTC Institute of Technology | And 2 more authors.
Nonlinear Dynamics | Year: 2016

This paper presents a theoretical model to analyze and predict the electromagnetic radiation (EMR) during the strain hardening of metals with negligible Peierls stress. The model developed is validated by comparing it with the experimental results on the ASTM B265 grade 2 titanium reported earlier. It is observed that inclusion of time-varying stress is essential to studying EMR occurring during strain hardening. The model confirms the observation that the amplitude of oscillatory EMR is generally much larger than the amplitude of exponential EMR. Further, the variation in viscous damping as a function of strain during strain hardening too has been incorporated in the model. The nature as well as amplitude of the EMR calculated by this model matches well with the earlier reported results on titanium. The model is thus suitable for studying the EMR during plastic deformation of metals and alloys with negligible Peierls stress. © 2016 Springer Science+Business Media Dordrecht

Singh R.,Birla Institute of Technology | Lal S.P.,Birla Institute of Technology | Misra A.,RTC Institute of Technology
Applied Physics A: Materials Science and Processing | Year: 2014

This paper presents some significant variations in the intermittent electromagnetic radiation (EMR) during plastic deformation under tension and compression of some metals with selected crystal structure, viz. zinc, hexagonal closed packed (hcp), copper, face-centred cubic (fcc: stacking fault energy 0.08 J/m2), aluminium (fcc: stacking fault energy 0.2 J/m2) and 0.18 % carbon steel, body-centred cubic (bcc). The intermittent EMR signals starting near yielding are either oscillatory or exponential under both modes of deformation except a very few intermediate signals, random in nature, in zinc under compression. The number and amplitude of EMR signals exhibit marked variations under tension and compression. The smooth correlation between elastic strain energy release rate and average EMR energy release rate suggests a novel technique to determine the fracture toughness of metals. The first EMR emission amplitude and EMR energy release rate occurring near the yield increase, but maximum EMR energy burst frequency decreases almost linearly with increase in Debye temperature of the metals under tension while all EMR parameters decrease nonlinearly under compression. These results can be developed into a new technique to evaluate dislocation velocity. The EMR amplitude and energy release rate of the first EMR emission vary parabolically showing a maxima with increase in electronic heat constant of the metals under tension while they first sharply decrease and then become asymptotic during compression. However, the variation in EMR maximum energy burst frequency is apparently similar under both modes of deformation. These results strongly suggest that the mechanism of EMR emission during plastic deformation of metals involves not only the interaction of conduction electrons with the lattice periodic potential as presented in the previous theoretical models but also the interaction of conduction electrons with phonons. However, during crack propagation and fracture, charge oscillations at fractured surfaces due to breaking of atomic bonds constitute an additional factor. © 2014, Springer-Verlag Berlin Heidelberg.

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