Disha Institute of Management and Technology

Raipur, India

Disha Institute of Management and Technology

Raipur, India

The Disha Institute of Management and Technology , is a university offering undergraduate and graduate degrees, located in Raipur, the capital of Chhatisgarh.It is part of the Disha Education Society affiliated with the Chhattisgarh Swami Vivekanand Technical University. Wikipedia.

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Nashine H.K.,Disha Institute of Management and Technology | Kadelburg Z.,University of Belgrade | Radenovic S.,University of Belgrade
Mathematical and Computer Modelling | Year: 2013

Common fixed point theorems for T-weakly isotone increasing mappings satisfying a generalized contractive type condition under a continuous function φ : [0, + ∞) →[0, + ∞) with φ (t) < t for each t> 0 and φ (0)= 0 in complete ordered partial metric spaces are proved. To illustrate our results and to distinguish them from the existing ones, we equip the paper with examples. © 2011 Elsevier Ltd.


Chandra V.K.,Chhatrapati Shivaji Institute of Technology | Chandra B.P.,Disha Institute of Management and Technology
Optical Materials | Year: 2011

Whereas the elastico mechanoluminescence (EML) of certain crystals increases linearly with the stress, nonlinearity occurs in the EML intensity versus stress plot of several crystals. The EML of crystals can be understood on the basis of piezoelectrically-induced detrapping model, whereby the localized piezoelectric field causes detrapping of electrons or holes and subsequently the capture of electrons in the excited states of activator ions, recombination of electrons in hole captured centres, recombination of holes in electron-captured centres or simply the electron-hole recombination gives rise to the light emission. Considering the piezoelectrically-induced detrapping model of EML expression is derived for the stress dependence of the EML intensity. It is shown that the crystals having uniform distribution of traps show linear relationship between the EML intensity and stress and the crystals having exponential distribution of traps show nonlinear relationship between the EML intensity and stress. The crystals having linear dependence of EML intensity on stress are suitable for the fabrication of EML-based stress sensors. The values of coefficient of deformation detrapping, relaxation time of the crosshead of the machine used to deform the samples and lifetime of the charge carriers in the shallow traps lying in the normal piezoelectric region of the crystals can be determined from the EML measurements. The values of the coefficient of deformation detrapping are 0.310, 0.018 and 0.021 MPa-1 for SrMgAl6O11:Eu, Sr2MgSi2O 7:Eu and SrCaMgSi2O7:Eu crystals, respectively. The coefficient of deformation detrapping is low for SrAl2O 4:Eu, SrAl2O4:Eu, Dy, SrBaMgSi 2O7:Eu and ZnS:Mn crystals and such crystals are suitable for EML-based stress sensors. A good agreement is found between the theoretical and experimental results. © 2011 Elsevier B.V. All rights reserved.


Chandra V.K.,Chhatrapati Shivaji Institute of Technology | Chandra B.P.,Disha Institute of Management and Technology | Chandra B.P.,Ashoka Institute of Technology and Management
Organic Electronics: physics, materials, applications | Year: 2012

In phosphorescent organic light-emitting diodes (PHOLEDs), both the rise time and decay time decrease with increasing amplitude of the applied voltage pulse. The rise time τ r of the transient electroluminescence (TEL) increases linearly with increasing value of the ratio of voltage V to the current j, that is, with V/j. Using the equations for the dynamics of charge carriers an expression is derived for the rise time τ r of the TEL in OLEDs. It is shown that τ r should increase with increasing values of the ratio (V/j), dielectric constant , and area of cross-section of the emission layer, however, it should decrease with the thickness of emission layer. For higher values of the applied voltage nonlinearity occurs in the τ r versus V/j plot because the increase in mobility of carriers at high electric field causes increase in the current flowing through the OLEDs. In fact, the rise time of TEL is related to the product of capacitance and effective resistance of the OLED. Considering the rate of generation and decay of radiative triplet excitons in the emission layer, an expression is derived for the decay time of TEL in PHOLEDs and it is shown that, for higher values of the time-constant of OLED, the decay time should be equal to the time-constant, however, for lower values of the time-constant, the decay time should be equal to the lifetime of radiative triplet excitons in the emission layer. A good agreement is found between the theoretical and experimental results. © 2011 Elsevier B.V. All rights reserved.


Chandra V.K.,Chhatrapati Shivaji Institute of Technology | Chandra B.P.,Disha Institute of Management and Technology | Chandra B.P.,Ashoka Institute of Technology and Management
Journal of Luminescence | Year: 2012

When a composite of suitable dimension formed by mixing the microcrystalline or nanocrystalline persistent luminescent materials in epoxy resin is deformed at a fixed pressing rate, then the elastico mechanoluminescence (EML) emission takes place after a threshold pressure, in which the EML intensity increases linearly with the applied pressure. When the applied pressure is kept constant or decreased linearly, then the EML intensity decreases with time, in which depending on the prevailing condition, the EML intensity initially decreases at a fast rate and then at a slow rate or sometimes it decreases exponentially having only one decay time. When a small ball is dropped from a low height onto the film of a persistent luminescent material, then initially the EML intensity increases with time, attains a peak value and then it decreases initially at a fast rate and later on at a slow rate. In this case, both the peak EML intensity and the total EML intensity increase linearly with the height through which the ball is dropped onto the film. Considering the piezoelectrically induced detrapping model based on successive detrapping of exponentially distributed traps a theoretical approach is made to the dynamics of light emission induced by elastic deformation of persistent luminescent crystals and thin films. It is shown that the EML intensity depends on several parameters such as pressure, pressing rate or strain rate, temperature, density of filled electron traps, piezoelectric constant near defect centers, etc. Both, in the case of slow deformation and impact stress, the fast decay time is related to the time-constant for the decrease of pressing rate of the samples and the slow decay time of EML is related to the lifetime of electrons in the shallow traps lying in the normal piezoelectric region of the crystals. Both, the EML produced during the release of pressure and the EML produced during the successive applications of pressure take place due to the detrapping of retrapped electrons in the vacant electron traps near activator ions, in which retrapping is caused by the thermally released electrons from the filled shallow traps lying in the normal piezoelectric region of the crystals, which get filled during the detrapping of stable traps at the time of increase of pressure. On the basis of the proposed model, the dependence of EML intensity on different parameters, dynamics of EML and physical concepts of the threshold pressure, characteristic piezoelectric field for detrapping, coefficient of deformation detrapping, nonlinear increase of the EML intensity of some crystals at high pressure and higher EML intensity in the crystals having higher coefficient of deformation detrapping can be satisfactorily understood. A good agreement is found between the theoretical and experimental results. It is shown that the present study may be helpful in tailoring the intense persistent elastico mechanoluminescent materials having long lasting time. © 2011 Elsevier B.V. All rights reserved.


Nashine H.K.,Disha Institute of Management and Technology | Samet B.,University of Tunis | Vetro C.,University of Palermo
Mathematical and Computer Modelling | Year: 2011

The purpose of this paper is to present some fixed point theorems for T-weakly isotone increasing mappings which satisfy a generalized nonlinear contractive condition in complete ordered metric spaces. As application, we establish an existence theorem for a solution of some integral equations. © 2011 Elsevier Ltd.


Dutta J.,Disha Institute of Management and Technology | Tripathi S.,Motilal Nehru National Institute of Technology | Dutta P.K.,Motilal Nehru National Institute of Technology
Food Science and Technology International | Year: 2012

In recent years, active biomolecules such as chitosan and its derivatives are undergoing a significant and very fast development in food application area. Due to recent outbreaks of contaminations associated with food products, there have been growing concerns regarding the negative environmental impact of packaging materials of antimicrobial biofilms, which have been studied. Chitosan has a great potential for a wide range of applications due to its biodegradability, biocompatibility, antimicrobial activity, nontoxicity and versatile chemical and physical properties. It can be formed into fibers, films, gels, sponges, beads or nanoparticles. Chitosan films have been used as a packaging material for the quality preservation of a variety of foods. Chitosan has high antimicrobial activities against a wide variety of pathogenic and spoilage microorganisms, including fungi, and Gram-positive and Gram-negative bacteria. A tremendous effort has been made over the past decade to develop and test films with antimicrobial properties to improve food safety and shelf-life. This review highlights the preparation, mechanism, antimicrobial activity, optimization of biocide properties of chitosan films and applications including biocatalysts for the improvement of quality and shelf-life of foods. © Author(s) 2011.


Nashine H.K.,Disha Institute of Management and Technology | Shatanawi W.,Hashemite University
Computers and Mathematics with Applications | Year: 2011

The purpose of this paper is to establish a coupled coincidence point for a pair of commuting mappings in partially ordered complete metric spaces. We also present a result on the existence and uniqueness of coupled common fixed points. An example is given to support the usability of our results. © 2011 Elsevier Ltd. All rights reserved.


Sodha M.S.,Disha Institute of Management and Technology | Misra S.,University of Lucknow | Mishra S.K.,University of Lucknow
Physics of Plasmas | Year: 2010

This paper presents an analysis of the kinetics of an illuminated complex plasma having spherical dust particles with a size distribution. It has been pointed out that in the steady state, the electric potential on the surface of all the particles is the same; as a corollary, all particles carry a charge of the same sign. It is seen that in the steady state, the plasma parameters are determined by the number per unit volume and root mean square radius of the dust particles. This fact makes the analysis similar to that for a complex plasma with dust of uniform size. It is seen that it is essential to consider both the number and energy balance of the constituents of the complex plasma. A parametric analysis, a discussion of the numerical results thus obtained, and conclusions have also been given. © 2010 American Institute of Physics.


Chandra B.P.,Disha Institute of Management and Technology
Journal of Luminescence | Year: 2011

A new technique called, mechanoluminescence technique, is developed for measuring the parameters of impact. This technique is based on the phenomenon of mechanoluminescence (ML), in which light emission takes place during any mechanical action on solids. When a small solid ball makes an impact on the mechanoluminescent thin film coated on a solid, then initially the elastico ML (EML) intensity increases with time, attains a maximum value Im at a particular time tm, and later on it decreases with time. The contact time Tc of ball, can be determined from the relation T c=2tc, where tc is the time at which the EML emission due to compression of the sample becomes negligible. The area from where the EML emission occurs can be taken as the contact area Ac. The maximum compression h is given by h=Ac/(πr), where r is the radius of the impacting ball, and thus, h can be determined from the known values of Ac and r. The maximum force at contact is given by F m=(2mU0)/Tc, where m is the mass of the impacting ball and U0 is the velocity of the ball at impact. The maximum impact stress σm can be obtained from the relation, σm=Fm/Ac=(2mU0)/(T cAc). Thus, ML provides a real-time technique for determining the impact parameters such as Tc, Ac, h, Fm and σm. Using the ML technique, the impact parameters of the SrAl2O4:Eu film and ZnS:Mn coating are determined. The ML technique can be used to determine the impact parameters in the elastic region and plastic region as well as fracture. ML can also be used to determine the impact parameters for the collision between solid and liquid, if the mechanoluminescent material is coated on the surface of the solid. The measurement of fracto ML in microsecond and nanosecond range may provide a tool for studying the fragmentations in solids by the impact. Using the fast camera the contact area and the depth of compression can be determined for different intervals of time. © 2011 Elsevier B.V. All rights reserved.


Chandra B.P.,Disha Institute of Management and Technology
Journal of Luminescence | Year: 2010

ZrO2:Ti phosphors show such a strong mechanoluminescence (ML) that it can be seen in day light with naked eye. When a pellet of ZrO 2:Ti phosphor mixed in epoxy resin is deformed in the elastic region at a fixed strain rate using a testing machine, ML intensity increases linearly with time, and when the deformation is stopped, ML intensity decreases exponentially with time. For a given strain rate, ML intensity increases linearly with pressure, and for a given pressure, ML intensity increases linearly with the strain rate. The total ML intensity, in the deformation region, increases quadratically with pressure; however, the total ML intensity in the post-deformation region increases linearly with pressure. ML intensity decreases with successive number of pressings, whereby the reduced ML intensity can be recovered by UV-irradiation of the sample. ML intensity increases linearly with density of filled electron traps and it is optimum for a particular concentration of Ti in ZrO2. ML intensity should change with increasing temperature of the phosphors. Although ZrO2 is non-piezoelectric as a whole, it seems that the local structures near the Ti ions in ZrO2 crystals are in the piezoelectric phase. The elastico ML in ZrO2 phosphors can be understood on the basis of the localized piezoelectrification-induced detrapping model. According to this model, the localized piezoelectric field near Ti ions causes detrapping of electrons and subsequently the detrapped electrons moving in the conduction band are captured by the energy state of excited Ti4 ions, whereby excited Ti 4 ions are produced and consequently the decay of excited Ti 4 ions gives rise to the light emission. The expressions derived on the basis of this model are able to explain satisfactorily the characteristics of ML. The relaxation time of localized piezoelectric charges and the threshold pressure for the ML emission can be determined from ML measurements. The long decay of elastico ML indicates the possibility of exploring persistent elastico ML, which may be useful for the fabrication of dim light sources capable of operating without any external power. © 2010 Elsevier B.V. All rights reserved.

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