DBS PG College

Dehradun, India

DBS PG College

Dehradun, India
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Singh A.K.,Institute Instrumentation Center | Chauhan S.,Institute Instrumentation Center | Balasubramanian P.,Institute Instrumentation Center | Srivastava S.K.,Dbs Pg College | Chandra R.,Institute Instrumentation Center
Thin Solid Films | Year: 2017

Epitaxial thin films of double perovskite Nd2NiMnO6 (NNMO) have been successfully grown on (001) oriented substrates of (LaAlO3)0.3-(Sr2AlTaO6)0.7 (LSAT), SrTiO3 (STO) and LaAlO3 (LAO) by pulsed laser deposition under optimum growth conditions. X-Ray diffraction and reciprocal space maps of the asymmetric (103) peak reveal that the films deposited on LSAT and STO substrates are fully relaxed, while a large in- plane compressive strain has been observed in film grown on LAO. This results into the coexistence of anti-site disorder and orthorhombic phase in the film deposited on LAO, which is further confirmed from observed shift and broadening in the antisymmetric vibrations in the Raman spectra. The temperature dependent magnetization shows a ferromagnetic transition close to 200 K in all the three samples. However, film grown on LAO substrate shows an additional upturn transition at ~ 96 K (T′), which could be ascribed to the formation of antisite disorders further responsible for reduction of saturation magnetization (~ 1.8 × 105 A/m) in hysteresis curve of the sample. The ordered structure obtained on LSAT and STO exhibit in-plane easy axis with a large coercivity of ~ 0.2 T, while, the film deposited on LAO does not show any preferred anisotropic direction. © 2017 Elsevier B.V.

Shaily,Indian Institute of Technology Roorkee | Shaily,DBS PG College | Kumar A.,DBS PG College | Ahmed N.,Indian Institute of Technology Roorkee
Industrial and Engineering Chemistry Research | Year: 2017

The coumarin-thiol-based colorimetric and fluorimetric chemosensor (E)-7-(diethylamino)-3-((2-mercaptophenylimino)methyl)-2H-chromen-2-one 1a was designed, synthesized, and evaluated for anion detection through the metal displacement mechanism. Chemosensor 1a exhibited a high sensitivity and selectivity to Hg2+ ion detection in HEPES-buffered solution [20 mM, 3:7 CH3CN/H2O (v/v), pH 7.0] with a 1:1 binding stoichiometry and a 5.549 × 105 M-1 binding constant. The fluorescence intensity of chemosensor 1a was selectively quenched by Hg2+, and an obvious color change from yellowish green to orange was observed by the naked eye. Moreover, a solution of the in situ generated 1a + Hg2+ complex displayed a high selectivity to CN- through the Hg2+ displacement approach. The gradual addition of CN- to the resultant solution of the 1a + Hg2+ complex induced its fluorescence recovery with a detection limit of 31 nM. This reversibility in fluorescence suggests the promising applicability of chemosensor 1a as an "on-off-on" naked-eye sensor. © 2017 American Chemical Society.

Muruganandam M.,Central Soil and Water Conservation Research and Training Institute CSWCRTI | Pande R.K.,DBS PG College | Sharda V.N.,Agricultural Scientists Recruitment Board ASRB | Mishra P.K.,CSWCRTI
Indian Journal of Traditional Knowledge | Year: 2014

A study carried out to assess existing basic knowledge and perceptions of farmers on fish farming in Uttarakhand Himalayas during 2003-08 indicated prevalence of as many as 16 mythical superstitions on fish identification, features of fishponds and various attributes of fishes or fish farming among farmers adding to already existing problems of fisheries development in the region. Preference for deeper fishponds or water harvesting structures (WHS) and coldwater river fishes against farmed or warm water river fishes; ignorance on the needs of liming or fertilization in fishponds and various benefits of fishes or fish farming other than for food purpose were widely held by 81-86% respondents. Ignorance on the negative impacts of fishing in rivers using powder prepared from the woody shrub, Zanthoxylum armatum DC., locally called as timru was observed in 69% respondents and probably this helps to continue periodically organized traditional fishing festivals, known as mound or machli mela using timru powder, that destroy riverine ecosystems in the region. Importance of water management in fish farming and potential of pig rearing or use of pig dung as fertilizer in fishponds or crop fields were not recognized by 50% respondents. Overall, ignorance on various principles, recommended practices and inputs of fish farming, features of fishes and fishing in rivers were prevalent in the region. A review made on issues of prevailing superstitions provided scientific and logical explanations either in support of them or otherwise. The paper identifies possible researchable issues associated with the myths and suggests dispelling unscientific superstitions maybe through appropriate research findings, trainings and positive demonstrations by the existing advisory systems.

Gupta V.K.,Indian Institute of Technology Roorkee | Gupta V.K.,King Fahd University of Petroleum and Minerals | Nayak A.,Indian Institute of Technology Roorkee | Agarwal S.,Indian Institute of Technology Roorkee | And 6 more authors.
Desalination and Water Treatment | Year: 2012

Arsenic is present in environment in trace amounts in rocks, soil, water and air but its toxicity effects are highly dependent on its chemical forms; inorganic and organic. There is a direct association between elevated arsenic exposure through drinking water and prevalence of different types of cancers. Present review describes the brief account of arsenic chemistry with reference to water and environment which is relevant to its toxicity arising out of different arsenic species and finally its remediation technologies. The quantification of arsenic species is difficult owing to the low concentration of arsenic in drinking water which is relatively lower than detection limits of modern analytical methods. New hyphenated techniques with more advanced tools have therefore, been discussed in the present paper which are being used in arsenic speciation analysis. The present review also highlights the importance to identify and quantify each chemical species of arsenic as more than 20 arsenic compounds are present in natural environment and in biological systems. Below microgram per liter detection limits are required to quantify arsenic species from these systems and a combination of chromatographic separation with atomic spectroscopy and mass spectroscopic detection is therefore, the most suitable speciation choice. The second important criteria viz. arsenic remediation from contaminated water for supply of safer drinking water is discussed and various remediation technologies are reviewed. © 2012 Desalination Publications. All rights reserved.

Joshi D.P.,DBS PG College | Sharma K.,Graphic Era University | Gill F.S.,Graphic Era University
Indian Journal of Pure and Applied Physics | Year: 2013

In the present paper, the dependence of transfer characteristics of PX-Si TFT devices on gate oxide thickness (tox) and inversion layer thickness (tsi) has been investigated theoretically by considering a new Gaussian energy distribution of GB trapping states. The dependence of drain current (ID) and GB space charge potential barrier height (q V g) of PX-Si TFT on gate voltage (VGS) at different inversion layer thickness qV g, and oxide layer thickness has also been studied. It is observed that the drain current increases on decreasing the thickness of oxide layer and inversion layer.

Dubey P.,Indian Institute of Technology Roorkee | Arya V.,Indian Institute of Technology Roorkee | Srivastava S.,Dbs Pg College | Singh D.,Indian Institute of Technology Roorkee | Chandra R.,Indian Institute of Technology Roorkee
Surface and Coatings Technology | Year: 2015

The effect of microstructure on thermal stability and mechanical properties of co-sputtered deposited Zr-W-B-N thin films on Si (100) substrates have been studied in detail. The power density of boron target has been varied from 0.1 to 7.5W/cm2 to obtained films of varying microstructure. Electron microscopy, X-ray diffraction analysis, atomic force microscopy, Raman scattering spectra, nano and micro indentations were used to investigate the interrelations between the microstructure and the variations in strength properties of nanocomposite Zr-W-B-N thin films. It has been observed that films with boron content<2.3at.% exhibited (200) preferred crystallographic orientation of grains and columnar structure. While the films of boron content ≥7.5at.% are columnarless with crystal phase grain size less than 7nm and of amorphous-crystalline structure. The film with boron concentration ~7.5at.% exhibits maximum hardness (~37GPa), wear resistance (H/Er ~0.24) and fracture toughness (2.9MPa·m1/2). Post annealing of the film with ~7.5at.% boron concentration has been carried out in vacuum (Tv) and air (Tn) up to 900°C. Zr-W-B(7.5at.%)-N film retains its fcc structure during vacuum annealing up to 900°C. Oxygen starts to incorporate at Tn =500°C and its percentage goes up with increasing Tn up to 900°C. © 2015 Elsevier B.V.

Kumar R.,DBS PG College | Sharma M.L.,Indian Institute of Technology Roorkee
Himalayan Geology | Year: 2011

Keeping in view the problem of increasing concern of the likelihood of occurrence of the next large earthquake in the seismically active regions in India where the last occurrence has crossed the return periods, the conditional probabilities have been estimated using Weibull and Gaussian distribution for the Indian region. The estimations have been carried out by dividing the Indian subcontinent into 24 seismogenic sources. The cumulative and conditional probabilities have been interpreted with respect to the last earthquake occurrence and in the time intervals of 15 and 50 years. Most of the regions in the country are found to be having lesser seismic hazard as compared with the results produced using classical probabilistic seismic hazard estimations. The use of conditional probabilities have been recommended for estimation of seismic hazard to take into account the last occurrence of earthquake in the region.

Tyagi A.P.,Dbs Pg College | Singh S.,Dn Pg College | Pandey R.K.,Dbs Pg College
Advances in Intelligent Systems and Computing | Year: 2014

Holding costs are determined from the investment in physical stocks and storage facilities for items during a cycle. In most of the research papers, holding cost rate per unit time for perishable inventory is assumed as constant. However, this is not necessarily the case when items in stock are decaying. In this work, paying better attention on the holding cost, we present a deteriorating inventorymodel in which the unit holding cost is continuously based on the deterioration of the inventory with the time the item is in stock. The deterioration rate is assumed as a Weibull distribution function. Decliningmarket demand is considered in this paper. Shortages are allowed and partial backlogged. The partial backlogging rate is a continuous exponentially decreasing function of waiting time in purchasing the item during stock out period. Conditions for uniquely existence of global minimum value of the average total cost per unit time are carried out. Numerical illustration and sensitivity analysis are presented. © Springer India 2014.

Singh A.K.,Indian Institute of Technology Roorkee | Chauhan S.,Indian Institute of Technology Roorkee | Srivastava S.K.,Dbs Pg College | Chandra R.,Indian Institute of Technology Roorkee
Solid State Communications | Year: 2016

The structural and magnetic properties of polycrystalline Nd2NiMnO6 (NNMO) synthesized by solid state reaction method have been investigated. Rietveld refinement of Powder X-Ray diffraction data suggests that NNMO compound crystallizes in monoclinic phase with space group P21/n. Magnetic measurements reveal an additional magnetic transition TC'~85K due to to Ni3+-O-Mn3+ antiferromagnetic superexchange interaction along with ferromagnetic transition ~196K in M-T curve, leading to antiferromagnetic interactions in this compound. High sintering temperature (upto 1100°C) leads to the formation of antisite disorders and antiferromagnetic antiphase boundaries in the present sample. The magnetic hysteresis measurements show ferromagnetic behavior with low saturation magnetization value (~2μB/f.u.) than the theoretical spin-only value (5μB/f.u.) of Ni/Mn ions. Hence, antisite disorders diminish the long range ferromagnetic ordering and also affect the magnetic properties of this compound. Exchange bias behavior has been observed in the hysteresis loops when the sample was field cooled from 300K to 5K. Exchange coupling between the ferromagnetic moments and antiferromagnetic antiphase boundaries is responsible for the observation of exchange bias in the present system. © 2016 Elsevier Ltd.

Tyagi A.P.,Dbs Pg College
International Journal of Industrial Engineering Computations | Year: 2014

Inventory management is considered as major concerns of every organization. In inventory holding, many steps are taken by managers that result a cost involved in this row. This cost may not be constant in nature during time horizon in which perishable stock is held. To investigate on such a case, this study proposes an optimization of inventory model where items deteriorate in stock conditions. To generalize the decaying conditions based on location of warehouse and conditions of storing, the rate of deterioration follows the Weibull distribution function. The demand of fresh item is declining with time exponentially (because no item can always sustain top place in the list of consumers' choice practically e.g. FMCG). Shortages are allowed and backlogged, partially. Conditions for global optimality and uniqueness of the solutions are derived, separately. The results of some numerical instances are analyzed under various conditions. © 2013 Growing Science Ltd. All rights reserved.

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