Punjab Technical University is a state university located at Kapurthala highway, Jalandhar, India.It was established by an act of State Legislature on 16 January 1997, to promote technical, management and pharmaceutical education in the state of Punjab at the degree level and above. Being an education and research university, it has a mandate to set up centers of excellence in emerging technologies for promoting training and research & development in these areas. Wikipedia.
Kalsi S.S.,Punjab Technical University |
Singh H.,Guru Nanak Dev University
Surface and Coatings Technology | Year: 2014
NiCrAlY and NiCoCrAlY coatings were deposited on Fe-based Superfer 800H superalloy with cold spray process. The aim of the present work is to compare hot corrosion behavior of NiCrAlY and NiCoCrAlY cold spray coatings on Fe-based superalloy in Na2SO4-10%NaCl environment at 900°C under cyclic conditions for 50cycles. The thermogravimetric technique was used to establish the kinetics of corrosion. The corrosion products have been analyzed using the XRD, SEM/EDAX and X-ray mapping techniques. Both coatings protect the underlying Superfer 800H. The NiCoCrAlY coating performed relatively better than NiCrAlY coating against hot corrosion in the given environment. © 2014 Elsevier B.V.
Singh G.,Punjabi University |
Singh H.,Punjabi University |
Sidhu B.S.,Punjab Technical University
Surface and Coatings Technology | Year: 2013
The objective of this study is to evaluate corrosion resistance of plasma sprayed hydroxyapatite (HA) and hydroxyapatite-silicon oxide (SiO2) coated Ti-6Al-4V substrate. In HA-SiO2 coatings, 10wt.% SiO2 was mixed with HA. The feedstock and coatings were characterized by X-ray diffraction and scanning electron microscopy/energy dispersive X-ray spectroscopy. The corrosion resistance was determined for the uncoated and two coatings. The corrosion resistance of the Ti-6Al-4V was found more after the deposition of the HA+10wt.% SiO2 rather than after HA coating and uncoated. Both HA, as well as, HA+10wt.% SiO2 coatings were crack free after 24h dipping in Ringer's solution for electrochemical corrosion. © 2013 Elsevier B.V.
Chatha S.S.,Punjabi University |
Sidhu H.S.,Punjabi University |
Sidhu B.S.,Punjab Technical University
Surface and Coatings Technology | Year: 2012
80Ni-20Cr and 75Cr 3C 2-25(Ni-20Cr) coatings were deposited on T91 boiler tube steel by high velocity oxy-fuel (HVOF) process to enhance high-temperature corrosion resistance. Hot corrosion studies were conducted on bare and HVOF-coated steel specimens after exposure to a molten salt (Na 2SO 4-60%V 2O 5) environment at 750°C under cyclic conditions. Each cycle consisted 1h of heating in the silicon carbide tube furnace followed by 20min of cooling in air. The weight change measurements were performed after each cycle to establish the kinetics of corrosion using thermogravimetric technique. X-ray diffraction (XRD), scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDAX) and X-ray mapping techniques were used to analyse the corrosion products. The bare steel experienced higher weight gain, which may be attributed to the formation of unprotective Fe 2O 3 dominated oxide scales. The 80Ni-20Cr coating was found to be more protective than the 75Cr 3C 2-25(Ni-20Cr) coating. The phases revealed in the oxide scale of the coated specimens were mainly oxides and spinels of nickel and chromium, which are reported to be protective against the hot corrosion. © 2012 Elsevier B.V.
Goyal T.,Punjab Technical University |
Walia R.S.,University of Punjab |
Materials and Manufacturing Processes | Year: 2012
In this article, Taguchi design of experiments L 18 orthogonal array have been adopted for making the electro-conductive coatings. Process parameters selected for this study are: substrate material, type of powder feeding arrangement, stagnation gas temperature, stagnation gas pressure, and standoff distance. The response parameter of cold spray coatings produced is measured in terms of coating thickness. The analyses of the raw data and Signal-to-Noise (S/N) ratio of the response parameters have been performed using analysis of variance (ANOVA). The optimum process parameters are predicted on the basis of analyses of the raw data and S/N ratio. The percentage contribution of the various process parameters with reference to coating thickness as response has been predicted. The significant process parameters in decreasing order of their contribution are: standoff distance, stagnation gas temperature, substrate material, stagnation pressure of the carrier gas, and feed arrangement of the powder particles. © 2012 Copyright Taylor and Francis Group, LLC.
Sharma H.,Punjab Technical University |
Singh R.,Max Planck Institute for Solid State Research
Journal of Physics Condensed Matter | Year: 2011
We investigate the ferromagnetism in ZnO clusters due to vacancy defects and C impurities doped at substitutional O or Zn sites, and interstitial sites. The total energy calculations suggest C at the O site is more stable than that at the Zn site in ZnO clusters. The total magnetic moments of Zn nOn-mCm clusters are 2.0μB/C. However, when two C atoms are bonded to the same Zn atom they interact antiferromagnetically and the total magnetic moment becomes less than 2.0μB/C. The interstitial C defects in ZnO clusters induce small magnetic moments. The combination of substitutional and interstitialC defects in ZnO clusters leads to magnetic moments of 0.0-2.0μB/C. The presence of vacancy defects in addition to substitutional C defects gives magnetic moments of greater than 2.0μB/C. These results suggest that the experimentally observed sample dependence of magnetic moments in ZnO systems is largely due to the different concentrations of substitutional and interstitial C impurities and the presence of vacancy defects in ZnO samples prepared under different growth conditions. © 2011 IOP Publishing Ltd.
Chandok S.,Punjab Technical University
Tamkang Journal of Mathematics | Year: 2012
Some common fixed point theorems for Ćirić type contraction mappings have been obtained in convex metric spaces. As applications, invariant approximation results for these type of mappings are obtained. The proved results generalize, unify and extend some of the results of the literature.
Gupta M.,Kurukshetra University |
Saxena J.,Punjab Technical University
Wireless Personal Communications | Year: 2013
In this paper planar and compact band stop filter using split ring resonator (SRR) metamaterial is proposed. Band stop type attenuation is presented from L-to X-band. Low insertion loss in the pass band and high attenuation in the stop band can be considered as the advantage of this filter. Filter characteristics of SRR is presented using microstrip line. Here SRR is introduced in the substrate layer of microstrip line. It has been observed that the rejection level of the filter in stop band goes on increasing as we increase the number of SRR in the structure. Size of SRR is much less than the operating wavelength thereby several SRR can be introduced in substrate layer to provide a compact structure with high rejection level in the stop band. The frequency of filtering depends on the dimensions of SRR. The effect of varying the dimensions of SRR on the filtering frequency is also presented in this paper. It has also been observed by Nicolson-Ross-Weir approach that at the filtering frequency, value of relative permeability as well as relative permittivity for this structure is negative. This confirms that this structure behaves as a Left Handed medium. © 2013 Springer Science+Business Media New York.
Sharma J.,Malout Institute of Management and Information Technology |
Sidhu B.S.,Punjab Technical University
Journal of Cleaner Production | Year: 2014
Millions of gallons of metal working fluids are used each day in industry for cutting, milling, drilling, stamping, and grinding. But Metal working fluids has been found causing very much damage to employee health and environmental pollution. High production volume, the large number of occupationally-exposed workers, and the lack of carcinogenicity and chronic toxicology data of metal working fluids demands a careful scrutiny. The aim of this research is to investigate the effects of dry and near dry machining (NDM) on AISI D2 steel by using an environmental friendly vegetable oil as a lubricant and to completely eliminate the mineral and petroleum based harmful lubricants from turning process. The high carbon high chromium AISI D2 steel was turned at various feed and speed combinations by using Tungsten carbide insert (CNMG12408). The results have been compared with dry machining and near dry machining. The experimental results indicate that near dry machining shows promising results over dry machining in terms of work-tool interface temperature and surface roughness. In order to obtain a good cutting performance by NDM, it is considered that at higher speeds better surface finish properties are obtained. Therefore, it is suggested that near dry machining, provides environment friendliness, cleaner production and can also help to improve the desirable machinability characteristics up to certain extent. © 2013 Elsevier Ltd. All rights reserved.
Talwar V.,Punjab Technical University |
Singh O.,Guru Nanak Dev University |
Singh R.C.,Guru Nanak Dev University
Sensors and Actuators, B: Chemical | Year: 2014
A novel route for the synthesis of polyaniline nanofibers in the presence of varying amounts of zinc oxide has been reported in this paper. The homogeneous PANI nanofibers were prepared through template approach, in which the ZnO nanoparticles were used as template. Structural, optical and morphological analysis of synthesized nanofibers was carried out using X-ray diffraction, UV-vis, IR spectroscopy and FESEM techniques. The thick films of the synthesized polyaniline powder were deposited on alumina substrate and their sensing response to ammonia gas was investigated. Optimum sensing response was achieved with PANI nanofibers synthesized in the presence of 30 wt% ZnO powder. The sensing response of fabricated sensor was proportional to the ammonia gas concentration and exhibited excellent selectivity toward ammonia gas. © 2013 Elsevier B.V.
Mittal R.,Malout Institute of Management and Information Technology |
Sidhu B.S.,Punjab Technical University
Journal of Materials Processing Technology | Year: 2015
Shielded metal arc welding (SMAW), gas tungsten arc welding (GTAW) and their combination are processed by using austenitic and nickel based diverse welding electrodes/filler wires to prepare the dissimilar weldments. The comparative evaluation of an appropriate welding process and welding consumable is based on microstructural features, micro-hardness variation, tensile testing and fracture morphology. The martensitic morphology is found responsible for the higher micro-hardness of HAZ of T91 side of all the weldments. Higher tensile strength (638.2 MPa) of GTAW, ERNiCr3 combination is observed than other weldments. The fractography corroborates the highest ductility of GTAW, ERNiCr3 combination with an elongation of 28.33% and the ductility of all the combinations of weldments except GTAW, ERNiCr3 is observed to be less than their base metals. Hence, it can be concluded that GTAW process, using nickel based weld metal offered the better results for the dissimilar joint between T91 and 347H. © 2015 Elsevier B.V. All rights reserved.