Indian Military Academy

Dehradun, India

Indian Military Academy

Dehradun, India
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Kumar N.,Indian Military Academy | Sharma P.,Manipal University India
Acta Technica CSAV (Ceskoslovensk Akademie Ved) | Year: 2016

Investigation of the unsteady free-convective flow of an electrically conducting viscous incompressible fluid passing through porous medium is conducted in the presence of transverse magnetic field applied normal to the direction of flow with heat source and thermal radiation. The governing equations of fluid flow have been solved using regular perturbation technique. This is observed that the small values of the Peclet number increase the thermal conductivity of the fluid and therefore, the heat is able to diffuse away from the heated surface more rapidly. Moreover, an increase in the thermal radiation leads to props up the fluid temperature within the boundary layer. Further, the non-dimensional shearing stress and the rate of heat transfer in terms of the Nusselt number at the walls of channel are also obtained. © 2016 Institute of Thermomechanics CAS, v.v.i.


Rana D.,Shoolini University of Biotechnology and Management Sciences | Jamwal D.,Shoolini University of Biotechnology and Management Sciences | Katoch A.,Indian Institute of Technology Roorkee | Thakur P.,Shoolini University of Biotechnology and Management Sciences | And 2 more authors.
Analyst | Year: 2016

The construction of dimethylenebis(eicosyldimethylammonium bromide) surfactant-directed gold nanoparticles (NPs) has been accomplished via a one-pot thermal reduction of HAuCl4 with trisodium citrate. The effect of cationic twin-tail surfactants, dimethylenebis(hexadecyldimethylammonium bromide) (16-2-16), dimethylenebis(octadecyldimethylammonium bromide) (18-2-18) and dimethylenebis(eicosyldimethylammonium bromide) (20-2-20), and their concentrations on shape and size of Au nanoparticles was thoroughly investigated. The UV-Vis spectroscopy and transmission electron microscopy (TEM) results show that longer tail length surfactants act as shape-directing agents promoting diversified morphologies. The formation of multiple-shaped Au nanoparticles, such as round, hexagonal, pentagonal, triangular and rod-like, has been confirmed from microstructure analysis; among them, many triangular shapes enhanced at elevated levels of surfactant concentration. In addition, the triangular Au nanoparticles with truncated corners were changed to smooth corners as the hydrocarbon chain length increased from (18-2-18) to (20-2-20). The concentration and hydrocarbon tails of twin-tail surfactants strongly influence the size and structure of Au NPs. In addition, the Au NPs synthesized with the twin-tail surfactant (18-2-18) were found to be highly sensitive towards Hg2+, which could be because of the preferential adsorption of Hg0 on the lower energy facets of triangular-shaped Au NPs. © The Royal Society of Chemistry 2016.


PubMed | Indian Institute of Technology Roorkee, Shoolini University of Biotechnology and Management Sciences, Italian Institute of Technology and Indian Military Academy
Type: Journal Article | Journal: The Analyst | Year: 2016

The construction of dimethylenebis(eicosyldimethylammonium bromide) surfactant-directed gold nanoparticles (NPs) has been accomplished via a one-pot thermal reduction of HAuCl4 with trisodium citrate. The effect of cationic twin-tail surfactants, dimethylenebis(hexadecyldimethylammonium bromide) (16-2-16), dimethylenebis(octadecyldimethylammonium bromide) (18-2-18) and dimethylenebis(eicosyldimethylammonium bromide) (20-2-20), and their concentrations on shape and size of Au nanoparticles was thoroughly investigated. The UV-Vis spectroscopy and transmission electron microscopy (TEM) results show that longer tail length surfactants act as shape-directing agents promoting diversified morphologies. The formation of multiple-shaped Au nanoparticles, such as round, hexagonal, pentagonal, triangular and rod-like, has been confirmed from microstructure analysis; among them, many triangular shapes enhanced at elevated levels of surfactant concentration. In addition, the triangular Au nanoparticles with truncated corners were changed to smooth corners as the hydrocarbon chain length increased from (18-2-18) to (20-2-20). The concentration and hydrocarbon tails of twin-tail surfactants strongly influence the size and structure of Au NPs. In addition, the Au NPs synthesized with the twin-tail surfactant (18-2-18) were found to be highly sensitive towards Hg(2+), which could be because of the preferential adsorption of Hg(0) on the lower energy facets of triangular-shaped Au NPs.


Sharma K.,University of the Free State | Kumar V.,University of the Free State | Chaudhary B.,Science and Engineering Research Board | Kaith B.S.,National Institute of Technology Jalandhar | And 2 more authors.
Polymer Degradation and Stability | Year: 2016

In this work, biodegradable hydrogel composite gum ghatti-co-poly(acrylic acid-aniline) (Gg-co-poly(AA-ANI) was prepared through graft copolymerization of ANI onto Gg-co-poly(AA) chains, in the presence of N,N'-methylene-bis-acrylamide (MBA) and ammonium persulphate (APS) as a crosslinker-initiator system in an aqueous solution. The matrix Gg-co-poly(AA) was synthesized by polymerizing AA onto Gg backbone using MBA and APS as a crosslinker-initiator system. The characterization of the crosslinked hydrogels has been carried out by Time of flight secondary ion mass spectroscopy, Fourier transform infrared, X-ray diffraction and thermogravimetric analysis. These spectroscopic studies confirmed the successful graft polymerization. The biodegradation of the crosslinked hydrogels was analysed using the composting soil method for two months. The initial and final weight of the crosslinked hydrogels were compared as well as the percentage degradation was calculated. The capability of the synthesized hydrogels to be employed as a colon-specific drug delivery vehicle was executed at various pH media using amoxicillin trihydrate as a model drug. The crosslinked hydrogel with the maximum percentage swelling was observed to show best drug absorption. Preliminary kinetic studied were conducted to get an estimated view of the release mechanism. © 2015 Elsevier Ltd. All rights reserved.


Thakur K.,Shoolini University of Biotechnology and Management Sciences | Kalia S.,Indian Military Academy | Sharma N.,Shoolini University of Biotechnology and Management Sciences | Pathania D.,Shoolini University of Biotechnology and Management Sciences
Journal of Molecular Catalysis B: Enzymatic | Year: 2015

Laccase-mediated biografting of p-coumaric acid was carried out on coconut fruit fibers to develop the new properties. Optimization of reaction parameters was carried out in order to get maximum biografting of p-coumaric acid. Maximum percentage biografting was observed at 4.5% (w/w) of p-coumaric acid, 40 U/g of laccase and 24 h incubation time. Grafted fibers were characterized by FTIR, SEM, XRD and TGA techniques in order to check the biografting, change in morphology, crystallinity and thermal stability, respectively. Moisture retention studies were carried out at 55% and 75% RH and biografting of p-coumaric acid has developed the hydrophobic nature in coconut fibers. Colony forming unit method was used to study the antibacterial behavior of fibers against the gram negative (Escherichia coli) and gram positive (Staphylococcus aureus) bacteria. Laccase-mediated biografting of p-coumaric acid has developed antibacterial property in the coconut fibers. © 2015 Elsevier B.V. All rights reserved.


Thakur K.,Shoolini University of Biotechnology and Management Sciences | Kalia S.,Indian Military Academy | Kaith B.S.,National Institute of Technology Jalandhar | Pathania D.,Shoolini University of Biotechnology and Management Sciences | Kumar A.,Shoolini University of Biotechnology and Management Sciences
RSC Advances | Year: 2015

In the present work, laccase from Trametes versicolor has been used for the biografting of natural phenol syringaldehyde (SA) on the surface of coconut fibers. Three parameters such as concentration of laccase, phenol and incubation period have been varied to optimize the reaction conditions for maximum biografting. Biografted coconut fibers were characterized with FTIR, SEM, and XRD techniques. Thermal, antibacterial and hydrophobic properties were analyzed by thermogravimetric analysis (TGA), colony forming unit (CFU) and moisture retention methods, respectively. An enhancement in the properties of coconut fibers was observed after biografting of SA. Modified coconut fibers were used as a reinforcement in the poly(butylene succinate) matrix to prepare biocomposites. Mechanical properties (tensile and flexural strength) of the biocomposites were evaluated by a universal testing machine. An increase in the mechanical strength of biocomposites was observed when reinforced with biografted fibers in comparison to unmodified coconut fibers. The fractured surface morphology of the composites indicated the better interlocking of the biografted fibers with the polymer matrix. © 2015 The Royal Society of Chemistry.


Thakur K.,Shoolini University of Biotechnology and Management Sciences | Kalia S.,Indian Military Academy | Pathania D.,Shoolini University of Biotechnology and Management Sciences | Kumar A.,Shoolini University of Biotechnology and Management Sciences | And 2 more authors.
Journal of Cleaner Production | Year: 2016

Biografting is a safe and clean procedure for surface functionalization of lignin-rich natural fibers replacing toxic chemicals with environmentally friendly enzyme catalysis. In the present work, laccase-catalyzed biografting of ferulic acid was carried out on the lignin component of coconut fibers to impart moisture and microbial resistance. Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron micrograph studies clearly indicate that ferulic acid is incorporated into the coconut coir lignin. Biografting was found to improve the thermal, antibacterial and hydrophobic properties of coconut fibers. © 2015 Elsevier Ltd.


PubMed | Indian Military Academy, Drexel University, Himachal Pradesh University and National Institute of Technology Jalandhar
Type: | Journal: Journal of environmental management | Year: 2015

Conducting hydrogels possessing antibacterial activity were developed using a two-step free-radical aqueous polymerization method to incorporate polyaniline chains into an adsorbent Guar gum/acrylic acid hydrogel network. The material properties of the synthesized samples were characterized using FTIR spectroscopy, thermal analysis and scanning electron microscopy techniques. Conducting hydrogels were tested for antibacterial activities against gram-positive Staphylococcus aureus and gram-negative Escherichia coli bacteria and demonstrated antibacterial activity. Synthesized hydrogel samples can be potential adsorbent materials for dye removal applications.


Sharma P.,Manipal University India | Kumar N.K.,Indian Military Academy | Sharma T.,Manipal University India
International Journal of Heat and Technology | Year: 2016

The aim of the present study is to analyze the entropy generation on forced convective flow of viscous incompressible fluid flow through a circular channel filled with a hyper porous medium saturated with a rarefied gas in the presence of transverse magnetic field, thermal radiation and uniform heat flux at the walls of the channel. For the Darcian model, the velocity and heat equations are analytically solved and the effects of various physical parameters on thses are discussed. In addition, the Entropy generation rate, Nusselt number and Bejan number are analyzed for different parameters. It was perceived that entropy generation number attains high values due to the thermal radiation. This is also concluded that rate of heat transfer upsurges due to the radiative heat tansfer and Brinkmann number.


PubMed | Indian Military Academy, King Saud University, Himachal Pradesh University and Sultan Qaboos University
Type: | Journal: International journal of biological macromolecules | Year: 2016

In this study, chitosan-crosslinked-poly (alginic acid) nanohydrogel (CN-cl-PL(AA)NHG) was synthesized by co-polymerization method. It was used an effective adsorbent for the exclusion of Cr(VI) metal ion from aqueous medium. The synthesized nanohydrogel was characterized by FTIR, SEM and TEM. The TEM images clearly indicated the appearance of smooth surface with average size of particles ranging from 30 to 80nm. The effect of different adsorption parameters like agitation time, temperature, initial metal ion concentration and adsorbent dosage was studied and optimized. The results demonstrated that the prepared chitosan-crosslinked-poly (alginic acid) nanohydrogel had high adsorption tendency for the removal of Cr(VI) from the aqueous solution. The pseudo-second-order equation represented the better adsorption kinetics for the adsorption process. The thermodynamic studies showed the adsorption of Cr(VI) onto CN-cl-PL(AA)NHG was spontaneous and chemical in nature.

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