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Item Electrical and magneto-resistance of Co/CNT/Epoxy thin film for strain and magnetic field sensing(2009) Anand, S.V.; Isaac, R.; Roy Mahapatra, D.R.Cobalt and iron nanoparticles are doped in carbon nanotube (CNT)/polymer matrix composites and studied for strain and magnetic field sensing properties. Characterization of these samples is done for various volume fractions of each constituent (Co and Fe nanoparticles and CNTs) and also for cases when only either of the metallic components is present. The relation between the magnetic field and polarization-induced strain are exploited. The electronic bandgap change in the CNTs is obtained by a simplified tight-binding formulation in terms of strain and magnetic field. A nonlinear constitutive model of glassy polymer is employed to account for (1) electric bias field dependent softening/hardening (2) CNT orientations as a statistical ensemble and (3) CNT volume fraction. An effective medium theory is then employed where the CNTs and nanoparticles are treated as inclusions. The intensity of the applied magnetic field is read indirectly as the change in resistance of the sample. Very small magnetic fields can be detected using this technique since the resistance is highly sensitive to strain. Its sensitivity due to the CNT volume fraction is also discussed. The advantage of this sensor lies in the fact that it can be molded into desirable shape and can be used in fabrication of embedded sensors where the material can detect external magnetic fields on its own. Besides, the stress-controlled hysteresis of the sample can be used in designing memory devices. These composites have potential for use in magnetic encoders, which are made of a magnetic field sensor and a barcode. © 2009 SPIE.Item Abstract Studies have been conducted on the effect of overstressing in rotary bending fatigue on the fatigue properties of an annealed and austempered ductile iron containing 1.5 Ni–0.3 Mo. For various R ratios S–N curves were determined and the fatigue limit estimated. It was found that the fatigue limit was a function of the level of overstressing and cycle ratio. In the case of austempered samples a beneficial effect of overstressing was observed at a certain level of overstressing. This was related to the work hardening behaviour of the austenite phase. In annealed samples, a reduction in the fatigue limit was observed at all levels of overstressing. Copyright © 1995, Wiley Blackwell. All rights reserved(EFFECT OF OVERSTRESSING ON FATIGUE BEHAVIOUR OF AUSTEMPERED DUCTILE IRON) Prasad Rao, P.; Padmaprabha1995Item Rotating bending fatigue tests were carried out on austempered ductile iron containing 1.5 wt% nickel and 0.3 wt% molybdenum. The ductile iron was austenitized at 900 or 1050 °C and then austempered at 280 or 400 °C for different lengths of time to obtain different microstructures. The fatigue strength was correlated with the amount of retained austenite and its carbon content, which were both determined by X-ray diffraction technique. While the tensile strength decreased with increasing retained austenite content, the fatigue strength was found to increase. Carbide precipitation was found to be detrimental to fatigue strength. Lower austenitizing temperature resulted in better fatigue strength. © 1994 Chapman & Hall.(Kluwer Academic Publishers, Effect of microstructure on the fatigue strength of an austempered ductile iron) Shanmugam, P.; Prasad Rao, P.; Rajendra Udupa, K.; Venkataraman, N.1994Item Austempered ductile iron containing 0.9 Ni and 0.3 Mo and subject to low stress dry sand abrasive testing shows that wear behaviour is very sensitive to heat treatment conditions. It is concluded that large retained austenite content promotes wear resistance.(Inst of Engineers (India), Low stress dry sand abrasive wear behaviour of austempered ductile iron) Prasad Rao, P.1995Item The direct conversion of benzene to phenol by hydroxylation with hydrogen peroxide was carried out over catalyst containing various transition metals impregnated on activated carbon. Iron and vanadium impregnated catalysts gave better yields of phenol compared to copper impregnated catalysts. The activity of transition metals supported on activated carbon catalyst in the production of phenol was V > Fe > Cu. In addition to the role of transition metals in catalyzing the hydroxylation reaction, the hydrophobic nature of the activated carbon surface and also the surface acidity and basicity seems to have enhanced the performance of these catalysts. © 2005 Springer Science + Business Media, Inc.(Transition metals supported on activated carbon as benzene hydroxylation catalysts) Choi, J.-S.; Kim, T.-H.; Choo, K.-Y.; Sung, J.-S.; Saidutta, M.B.; Song, S.-D.; Rhee, Y.-W.2005Item The direct conversion of benzene to phenol by hydroxylation with hydrogen peroxide was carried out over catalysts containing iron impregnated on activated carbon. Iron was impregnated on various surface modified activated carbons. The catalyst that was made by treating activated carbon with nitric acid, that was treated thermally in the presence of nitrogen at 600 °C and impregnated with 5 wt.% iron, gave a phenol yield of 20%. It was found that the synergistic interactions of surface groups and the impregnated iron have enhanced the performance of these catalysts. © 2005 Elsevier B.V. All rights reserved.(Direct synthesis of phenol from benzene on iron-impregnated activated carbon catalysts) Choi, J.-S.; Kim, T.-H.; Choo, K.-Y.; Sung, J.-S.; Saidutta, M.B.; Ryu, S.-O.; Song, S.-D.; Badekai Ramachandra, B.; Rhee, Y.-W.2005Item Influence of austenitising temperature on the formation of strain induced martensite in austempered ductile iron(2008) Daber, S.; Ravishankar, K.S.; Prasad Rao, P.P.The present work was taken up to study the influence of austenitising temperature on the formation of strain-induced martensite in austempered ductile iron. Ductile iron containing 1.5 wt.% nickel, 0.3 wt.% molybdenum and 0.5 wt.% copper was subjected to austempering treatments which consisted of three austenitising temperatures, namely 850, 900 and 950 °C, and three austempering temperatures, namely 300, 350 and 400 °C. Tensile tests were carried out under all the heat-treatment conditions and strain-hardening behaviour was studied by applying Hollomon equation. Microstructures were studied by optical microscopy and X-ray diffraction. It was found that increasing austenitising temperature increased the tendency for the formation of strain-induced martensite at all the austempering temperatures. © 2008 Springer Science+Business Media, LLC.Item Air quality assessment of Dhanbad District, India - A case study(2010) Anantharamu, A.; Singh, G.; Venkat Reddy, D.Ambient air pollution status in Dhanbad district is studied and presented in this article. The selection of Dhanbad is made considering its importance and the nature of activities taking place around the district. For the assessment of ambient air quality in Dhanbad, the following five locations were chosen: Main Gate of Indian School of Mines(ISM), Dhanbad: It is a site representing purely commercial activities and road traffic. Bankmore: It is one of the busiest marketing centres of the district and is surrounded by residential areas. All the vehicles going to Bokaro pass by this place and thus the traffic density is pretty high. Kusunda: It is a place 10.9 kilometres from Dhanbad Railway Station. It is just beside one of the coal mines, hence, all vehicles going to the mine passes through this place. Steel Gate: It consists of a small market. Trucks and other heavy vehicle are more frequent during night as this road connects to a highway. ISM Admin Block: It can be considered as a sensitive area since it is a very calm place where the usage of vehicles is minimum throughout the day. Monitoring of ambient air quality is done following the standard procedure prescribed in IS: 5182. In addition, the concentration of lead, zinc, cadmium, copper, manganese and iron metals in SPM is also monitored. The ambient air quality assessment was done in the month of June, 2009. The concentration of SPM was higher than the permissible limit in three locations namely ISM Main Gate, Bankmore and Steel Gate, while it was less than the permissible limit in other two locations, ISM Admin Block and Kusunda. Since the generation of SPM was mainly due to vehicular traffic it was expected to cross the limit in the above mentioned three locations as density of vehicular movement is very high. © 2010 CAFET-INNOVA TECHNICAL SOCIETY.Item Electroplating and characterization of Zn-Ni, Zn-Co and Zn-Ni-Co alloys(2010) Eliaz, N.; Venkatakrishna, K.; Hegde, A.C.Zn-Ni, Zn-Co and Zn-Ni-Co coatings were electrodeposited on mild steel from an acidic chloride bath containing p-aminobenzenesulphonic acid (SA) and gelatin. These additives changed the phase content in the coatings, most likely as a result of their adsorption at the surface of the cathode. The effect of gelatin was more pronounced than that of SA. The Faradaic efficiency was higher than 90%. As the current density was increased or the bath temperature was decreased, the concentration of the nobler metal in the coating increased. Both concentrations of Ni and Co in the ternary alloy increased as the applied current density was increased. Nickel and cobalt were found to have a synergistic catalytic effect. The thickness of all coatings increased as the applied current density was increased. The hardness increased with current density to a peak value, and then decreased. The rate of Zn deposition was heavily influenced by mass-transport limitation at high applied current densities, while the rates of Ni and Co deposition were not. The anomalous codeposition was explained by the great difference between the exchange current densities of Zn and the iron-group metal. Potentiodynamic polarization scans and electrochemical impedance spectroscopy showed that the corrosion resistance of the ternary Zn-Ni-Co alloy coatings was approximately 10 times higher than that of Zn-Ni and 7 times higher than that of Zn-Co. The improved corrosion resistance of the ternary alloy was attributed to its surface chemistry, phase content, texture, and surface morphology. The ternary Zn-Ni-Co coating may thus replace the conventional Zn-Ni and Zn-Co coatings in a variety of applications. © 2010 Elsevier B.V.Item A comprehensive assessment of increased iron ore production on the environment - A case study(2011) Thimmaiah, S.A.; Rao, Y.; Murthy, C.H.S.N.There has been a significant increase in iron ore production in the Bellary- Hospet-Sandur sector of Karnataka, India due to sudden increase in the demand of iron ore from other countries as well as by local steel plants set up in the region. An attempt has been made in this paper to study the effect of increase in the iron ore production on various environmental parameters like air, water, soil and noise. For this purpose a study area of 10 Km radius was taken and the various environmental parameters were monitored before and after increase in iron ore production in the region. Study shows that there is no significant change in the air quality in terms of SPM, RPM, SO2 and NOx in the region. In many locations, there is decrease in the concentrations of these parameters. This is mainly due to improvement of roads by asphalting, effective covering of iron ore trucks by tarpaulin, awareness among mine owners about the protection of environment by following various pollution control measures, dust suppression measures on the public road using water sprinklers and stringent monitoring of the environmental protective measures by various regulatory authorities. The concentration of SO2 and NOx was found to increase due to increase in traffic by movement of tippers in the public/village road. The deployment of heavy earth moving machinery at mine site also contributed for increase of SO2 and NOx. The surface water quality parameters were found to be within the acceptable limits in the study area. There is no possibility of disturbing/altering ground water table due to mining operations as the mining is being carried out on hill top which is above the general ground level. In agricultural soil, except that of potassium and electrical conductivity, variations in other parameters are insignificant as the agricultural lands are located 2 to 3 Kms away from the active mining area. Increase in noise level is found at most of the locations of the study area. Therefore, serious attempts should be made by mine owners as well as statutory bodies to reduce the sound level at various locations for increasing the quality of life in these locations in terms of sound level. © 2011 CAFET-INNOVA technical society. All right reserved.