GGDSD College

Chandigarh, India

GGDSD College

Chandigarh, India

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Sharma V.K.,Panjab University | Goyal A.,GGDSD College | Raju T.S.,Karunya University | Kumar C.N.,Panjab University | Panigrahi P.K.,Indian Institute of Science
Optical Fiber Technology | Year: 2015

We investigate modulational instability (MI) in a planar dual-core waveguide (DWG), with a Kerr and non-Kerr polarizations based on coupled nonlinear Schrödinger equations in the presence of linear coupling term, coupling coefficient dispersion (CCD) and other higher order effects such as third order dispersion (TOD), fourth order dispersion (FOD), and self-steepening (ss). By employing a standard linear stability analysis, we obtain analytically, an explicit expression for the MI growth rate as a function of spatial and temporal frequencies of the perturbation and the material response time. Pertinently, we explicate three different types of MI-spatial, temporal, and spatio-temporal MI for symmetric/antisymmetric continuous wave (cw), and spatial MI for asymmetric cw, and emphasize that the earlier studies on MI in DWG do not account for this physics. Essentially, we discuss two cases: (i) the case for which the two waveguides are linearly coupled and the CCD term plays no role and (ii) the case for which the linear coupling term is zero and the CCD term is nonzero. In the former case, we find that the MI growth rate in the three different types of MI, seriously depends on the coupling term, quintic nonlinearity, FOD, and ss. In the later case, the presence of quintic nonlinearity, CCD, FOD, and ss seriously enhances the formation of MI sidebands, both in normal as well as anomalous dispersion regimes. For asymmetric cw, spatial MI is dependent on linear coupling term and quintic nonlinearity. Copyright © 2015 Elsevier Inc. All rights reserved.


Kumar R.,Ggdsd College | Sekhon S.S.,Guru Nanak Dev University | Sekhon S.S.,University of the West Indies
Ionics | Year: 2013

The addition of polymer to liquid electrolytes containing trifluoromethanesulfonic acid (HCF3SO3) in propylene carbonate (PC) has been found to result in an increase in conductivity of gel electrolytes. The increase in conductivity has been observed to be due to the dissociation of ion aggregates present in the electrolytes which has also been supported by Fourier transform infrared studies. The maximum ionic conductivity (at 25 °C) of 7.55 × 10-3 S/cm has been observed for polymer gel electrolytes containing 1.5 wt% polymethylmethacrylate in 0.5 M solution of HCF3SO3 in PC. Polymer gel electrolytes have been found to be thermally stable up to a temperature of 125 °C by simultaneous differential scanning calorimetry/thermogravimetric analysis studies. The conductivity of polymer gel electrolytes does not show any appreciable change over a limited period of time. © 2013 Springer-Verlag Berlin Heidelberg.


Dogra S.,GGDSD college | Sharma M.L.,University of Punjab | Singh J.,University of Punjab
Comptes Rendus Chimie | Year: 2015

Various ionic liquids (ILs) were screened for their phase-transfer catalytic (PTC) activity using the N-alkylation of nitrogen heterocycles as the model reaction. Immobilized ILs behaved extremely well and proved to be far better catalysts than conventional homogeneous PTCs in terms of their stability, easy recovery, and reusability. The investigation also demonstrated that quaternary tetraalkylammonium salts offer very high catalytic activity, whereas aromatic heterocyclic tetravalent nitrogen catalysts (imidazolium- and pyridinium-based salts) were poorly active. © 2015 Académie des sciences.


Batra N.,GGDSD College | Singh J.,Panjab University | Joshi A.,Shri Guru Gobind Singhji Institute of Engineering and Technology | Bhatia S.,Panjab University
International Journal of Biological Macromolecules | Year: 2011

Bacillus coagulans RCS3 isolated from hot water springs secreted five isozymes i.e. β-gal I-V of β-galactosidase β-gal III isozyme was purified using DEAE cellulose and Sephadex G 100 column chromatography. Its molecular weight characterization showed a single band at 315kD in Native PAGE, while two subunits of 50.1 and 53.7kD in SDS PAGE. β-Gal III had pH optima in the range of 6-7 and temperature optima at 65°C. It preferred nitro-aryl-β-d-galactoside as substrate having K m of 4.16mM with ONPG. More than 85% and 80% hydrolysis of lactose (1-5%, w/v) was recorded within 48h of incubation at 55°C and 50°C respectively and pH range of 6-7. About 78-86% hydrolysis of lactose in various brands of standardized milk was recorded at incubation temperature of 50°C. These results marked the applications of β-gal III in processing of milk/whey industry. © 2011 Elsevier B.V.


Singh J.,Panjab University | Sinha S.,Panjab University | Batra N.,GGDSD College | Joshi A.,Shri Guru Gobind Singhji Institute of Engineering and Technology
Environmental Technology | Year: 2012

Peroxidases have been known to polymerize phenolic compounds and precipitate them from solution. Sapindus peroxidases (SPases) were extracted from the leaves of Sapindus mukorossi and precipitated with four volumes of chilled methanol. Soluble, encapsulated and cross-linked forms of enzymes were used for the removal of phenolic compounds (initial concentration 1.0 mM) in a stirred batch reactor. Calcium alginate beads were prepared using sodium alginate and calcium chloride at 1.5% and 5.0% (w/v), respectively. Sodium alginate and glutaraldehyde at 1.0% (w/v) and 0.8% (v/v), respectively, were optimized for cross-linking of SPases. The maximal removal of 2-chlorophenol was found in the buffers of pH range 4-7 and at 30-60 °C in the presence of 1.2mM H 2O 2 by soluble enzymes, but encapsulated and cross-linked enzymes worked well at pH 5 and at 50 °C in the presence of 0.8mM H 2O 2. The optimized doses of soluble, encapsulated and cross-linked SPases were 1.2, 4.2 and 1.2 mg/mL, respectively, for the removal of phenolic compounds. Encapsulated and cross-linked enzymes showed a lower efficiency than soluble enzyme but can be reused in multiple cycles for the removal of phenolic compounds. © 2012 Taylor & Francis.


Sharma V.K.,Panjab University | Goyal A.,GGDSD College
Journal of Nonlinear Optical Physics and Materials | Year: 2014

In this paper, we present bright and dark optical solitons induced by the non-Kerr terms in generalized nonlinear Schrödinger equation. The reported solutions consist of various soliton-like solutions including double-kink and algebraic solitons. These solitons are of sub 10 femtosecond width and are helpful to increase the information carrying capacity in order to make ultrafast communication. © 2014 World Scientific Publishing Company.


Kumar K.,Chitkara University | Chitkara M.,Chitkara University | Sandhu I.S.,Chitkara University | Mehta D.,Panjab University | Kumar S.,Ggdsd College
Journal of Alloys and Compounds | Year: 2014

Polyvinyl pyrrolidone (PVP) capped Zn1-xFe xO (0.000001 ≤ x ≤ 0.1) nanocrystalline powders were prepared by chemical co-precipitation technique. Structural, optical and magnetic characterizations of the annealed samples were performed using X-ray powder diffraction (XRD), transmission electron microscope (TEM), energy dispersive X-ray fluorescence (EDXRF), Fourier-transform infrared (FTIR) spectroscopy, UV-visible spectrophotometry, photoluminescence (PL) and vibrating sample magnetometer (VSM) measurements. XRD and TEM studies reveal that the synthesized ZnO nanocrystals have hexagonal wurtzite structure with average crystalline size ∼8-15 nm. EDXRF and FTIR measurements confirmed the doping and incorporation of Fe impurities in ZnO nanostructures. Photocatalytic efficiency of the synthesized samples was determined by degradation of methylene blue (MB) dye in aqueous solution under UV/sunlight exposure. The dependence of photocatalytic behavior and luminescence efficiency on the dopant concentration was studied in detail. Magnetic measurements performed at room temperature show that pure ZnO exhibits diamagnetic behavior, ferromagnetic order was clearly observed at minute concentration of Fe impurity (at 0.000010%) and large concentration of dopant (at 10%) leads to strong paramagnetic component in all the Fe-doped ZnO samples. © 2013 Elsevier B.V. All rights reserved.


Sharma S.,GGDSD College | Ahuja G.,Panjab University
Springer Proceedings in Physics | Year: 2016

Starting with the most general mass matrices, within the context of StandardModel and some of its extensions, incorporating the ideas of weak basis transformations and ‘naturalness’, we find that there exists a particular set of texture specific quark mass matrices which can be considered to be the minimal viable option. © Springer International Publishing Switzerland 2016.


Birbian N.,Panjab University | Singh J.,Panjab University | Jindal S.K.,PGIMER | Joshi A.,Shri Guru Gobind Singhji Institute of Engineering and Technology | And 2 more authors.
Lung | Year: 2012

Background: According to the National Family Health Survey, asthma is one of the leading diseases in India. In order to understand the complexity of asthma, the susceptibility genes need to be targeted for their association. Glutathione S-transferases play a major role in the detoxification of metabolites of oxidative stress resulting in inflammation and asthma. In the present study, the hypothesis that GSTT1 and GSTM1 gene polymorphisms are associated with asthma was examined. Methods This is the first study to investigate the role of GSTT1 and GSTM1 gene polymorphisms in asthma pathogenesis in a North Indian population. A total of 824 subjects were recruited, of which 410 were asthma patients, including 323 patients suffering from allergic rhinitis. The other 414 recruits were healthy controls from regions of North India. Multiplex PCR was used for genotyping the GSTT1 and GSTM1 gene polymorphisms. Results The GSTT1 null allele was more prevalent in asthma patients (40 %) than in the control subjects (13.3 %), which yielded a nearly fourfold risk towards asthma with odds ratio (OR) (95 % CI) - 4.35 (3.04-6.24), % - 75.34, and p - 0.000. The GSTM1 polymorphism also revealed a greater prevalence of the GSTM1 null allele in asthma patients (46.6 %) than in controls (39.4 %). Statistical analysis yielded a marginal risk toward asthma with OR (95 % CI) - 1.34 (1.01-1.79), j2 - 4.37, and p - 0.036. Conclusions: Polymorphisms as a result of deletions in the GSTT1 and GSTM1 genes confer an increased risk towards asthma thereby suggesting the protective role of these functional genes in the development of the disease. © Springer Science+Business Media, LLC 2012.


Pathak A.,GGDSD College | Sharma V.,Panjab University | Kumar S.,Panjab University | Dhawan D.K.,Panjab University
BioMetals | Year: 2011

Diabetes is a life threatening disease and its onset is linked with both environmental and genetic factors. Zinc metabolism gets altered during diabetes and results in many complications. The present study was designed to elucidate the effects of zinc supplementation on the biokinetics of 65Zn in whole body, liver and its biodistribution in diabetic rats. The animals were divided into four groups viz; normal control; diabetic (single intraperitoneal injection of alloxan 150 mg/kg body weight); zinc treated (227 mg/l in drinking water); and diabetic + zinc treated. To carry out biokinetics study, each rat was injected intraperitoneally with 0.74 MBq radioactivity of 65Zn following 4 weeks of different treatments and the radioactivity was determined by using a suitably shielded scintillation counter. Alloxan induced diabetic rats showed a significant decrease in both the fast (Tb 1) and slow (Tb 2) components of biological half-life of 65Zn which, however, were normalized in whole body (P > 0.05) following zinc supplementation. In case of liver, Tb 2 component was brought back to the normal but Tb 1 component was not increased significantly. The present study indicates that the paucity of zinc in the tissues of the diabetic animals was due to decreased retention of tissue zinc as evidenced by increased serum Zn, hyperzincuria and increased rate of uptake of 65Zn by the liver. Zinc supplementation caused a significant improvement in the retention of zinc in the tissues and is therefore likely to be of benefit in the treatment of diabetes. © 2011 Springer Science+Business Media, LLC.

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