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Haridwar, India

Singh R.G.,University of Delhi | Singh F.,Inter University Accelerator Center | Kumar V.,Gurukula Kangri University | Mehra R.M.,University of Delhi
Current Applied Physics

In this paper, we report temperature dependent studies of ZnO nanocrystallites deposited by the sol-gel spin coating process. The films are annealed at different temperature from 500 to 900 °C to grow the size of crystallites in controlled environment. The crystallite size, lattice parameters, and strain in the nanocrystallites are calculated. A coarsening kinetics is understood by Lifshitz, Slyozov and Wagner (LSW) theory and the activation energy of the coarsening process is estimated. Optical absorption and Photoluminescence (PL) measurements were carried out to investigate the effect of coarsening on optical properties of the ZnO thin films. The origin of PL spectra is explained in terms of the stabilization of structural defects and size of the crystallites. © 2010 Elsevier B.V. All rights reserved. Source

Chopra A.K.,Gurukula Kangri University | Chamoli S.,Gurukula Kangri University
Environmental Monitoring and Assessment

In recent years, various environmental issues have aroused a concern on the pollution of pesticides in rivers and in their various intercompartments. Multiple residues of pesticides discharged from industries or as a result of extensive use of agrochemicals in agriculture have been monitored. These pesticide residues contaminate the river ecosystem and its intercompartments such as sediments, and aquatic biota, and make it harmful to humans when they contaminate food and drinking water. The pesticide contamination in water, sediments, and aquatic biota has been reported to be beyond the acceptable range. The most commonly found pesticides are organochlorine, namely, dichlorodiphenyltrichloroethane, hexachlorocyclohexane, endosulfan, heptachlor, lindane, dieldrin, aldrin, endrin, and others. The paper discusses the general description, classification, and toxicity of pesticides; it also aims to create public awareness among people and appraise them with various alternate methods to combat the problem of pesticide contamination. An attempt has also been made to elucidate the findings of various works on pesticides in aquatic system and to highlight the challenging aspects of pesticide contamination, which have not attracted the attention of investigators yet. © 2010 Springer Science+Business Media B.V. Source

Kumar V.,Gurukula Kangri University | Singh R.G.,University of Delhi | Purohit L.P.,Gurukula Kangri University | Mehra R.M.,Sharda University
Journal of Materials Science and Technology

The paper has reported the structural, transport and optical properties of boron doped zinc oxide (ZnO:B) thin films grown on glass substrate by sol-gel spin coating process. It is observed from the analysis of the X-ray diffraction (XRD) results that the crystalline quality of the films is improved with increasing B concentration. A crystallite size of ∼17 nm is obtained for B doped films. A minimum resistivity of 7.9×l0-4 Ω·cm is obtained at 0.6 at.% of B concentration in the ZnO:B films. Ionized and intragrain cluster scattering are found to dominate the scattering mechanism in ZnO:B films. Optical interference pattern in transmittance spectra shows good homogeneity with a transparency of ∼88% in the visible region. The band gap of the films is increased from 3.24 to 3.35 eV with increasing B concentration. Band gap widening is analyzed in terms of Burstein-Moss shift. The origin of the broad band photoluminescence (PL) spectra is explained in terms of the intragrain cluster scattering. © 2011 The Chinese Society for Metals. Source

Kumar V.,Gurukula Kangri University | Chopra A.K.,Gurukula Kangri University
Bulletin of Environmental Contamination and Toxicology

A pot experiment was conducted to study the accumulation and translocation of metals in French bean (Phaseolus vulgaris L.). Plants were grown in soil amended with up to 100 % sewage sludge. Significant (p < 0.01) changes to soil characteristics were observed. The maximum growth of P. vulgaris was noted in the treatment with 40 % of sewage sludge. Metal concentrations were significantly (p < 0.05) higher in P. vulgaris after sewage sludge amendment where Fe > Zn > Cd > Cu > Cr > Pb. The translocation for Fe and Zn was in the order of leaves > shoot > root > fruits, for Cd, shoot > root > leaves > fruits, for Cu and Pb shoot > leaves > root > fruits and for Cr root > shoot > leaves > fruits of P. vulgaris. All accumulated metal concentrations except Cd in the fruit were below the FAO/WHO standard limits. Thus, the amendment of agricultural soil by sewage sludge might be feasible. However, a regular monitoring of metal levels in agricultural products is recommended to prevent their accumulation in the food chain. © 2013 Springer Science+Business Media New York. Source

Kumar V.,Gurukula Kangri University | Chopra A.K.,Gurukula Kangri University
Journal of Environmental Science and Technology

The present investigation was conducted to monitor the physico-chemical and microbiological characteristics of Municipal Wastewater (MWW) at treatment plant, Haridwar, installed under Ganga Action Plan (GAP)/National River Action Plan (NRAP) to control the pollution of river Ganga. The results revealed that the untreated MWW has high inorganic and organic pollution load. The treatment plant received the MWW from various Sewage Pumping Stations (SPSs) being treated through different stages viz. primary (physical), secondary (chemical) and tertiary (disinfection) treatments. In the present study, a significant (p<0.001) decrease was observed in the physico-chemical and microbiological parameters viz. turbidity, Total Suspended Solids (TSS), Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Chlorides (Cl -), alkalinity, hardness, free carbon dioxide (CO 2), Total Kjeldahl Nitrogen (TKN), phosphate (PO 4 3-), sulphate (SO 4 2-), iron (Fe 2+), Most Probable Number (MPN) and Standard Plate Count (SPC) after treatment. The Electrical Conductivity (EC), pH, Dissolved Oxygen (DO), Zinc (Zn), Cadmium (Cd), Copper (Cu), Nickel (Ni) and Chromium (Cr) were also recorded to be significantly (p<0.01) decreased in treated MWW. The maximum removal of turbidity (66.92%), TSS (88.37%), EC (89.43%), pH (14.18%), BOD (91.31%), COD (91.84%), CT (86.76%), alkalinity (90.42%), hardness (39.06%), free CO 2 (79.23%), TKN (71.40%), PO 4 3- (90.16%), SO 4 2- (85.90%), Fe 2+ (95.86%), Zn (95.06%), Cd (87.50%), Cu (92.30%), Ni (91.30%), Cr (85.71%) and MPN (99.99%) and SPC (99.99%) of MWW were recorded after final treatment. The maximum increase in DO (135.28%) was recorded in finally treated (outlet) wastewater. Thus the treatment plant had a significant role in the control of pollution loads of wastewater installed under GAP/ NRAP at Haridwar city. © 2012 Asian Network for Scientific Information. Source

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