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Study of effect of modulations on the onset of rayleigh benard convection in a couple stress fluid
In this thesis we study the linear and non-linear analyses of Rayleigh-Benard convection in a couple stress fluid. The effect of rotational modulation, temperature modulation and gravity modulation in the presence of external constraints like magnetic field and electric field are studied. The problems investigated in this thesis throw light on externally controlled convection in a couple stress fluid. The problems investigated in this thesis have possible applications in geophysics, astrophysics, oceanography engineering and experiment/ space situations with g-jitter connected with gravity simulation studies. with this motivation, we investigate in this thesis four problems and, their summary is given below one by one. (i)Linear and non-liner analyses of rotational modulation on Rayleigh-Benard convection in a couple stress fluid. The linear and non-linear analyses of Rayleigh-Benard convection in a couple stress fluid with rotational modulation is studied. The linear and non-linear analyses are, respectively based on normal mode technique and truncated representation of fourier series. The expression for Rayleigh number and correction Rayleigh number are obtained using regular perturbation method in the case of liner theory. The resulting no-autonomous lorenz model obtained in no-linear analysis is solved numerically using the Runge-Kutta-Fehlberg45 method to quantify the heat transport. The effect of rotational modulation is shown to be stabilizing there by leading to a situation of reduced heat transfer. The problem suggests an elegant method of controlling internal convection.(ii) Linear and non-linear analyses of gravity modulation on Rayleigh-Benard convection in a weakly electrically conducting couple strss fluid.The effect of time-periodic body force on the onset of Rayleigh-Benard convection in weak electrically conducting couple stress fluid is investigated. The stability of the horizontal fluid layer heated from below is examined by assuming time periodic body acceleration. -
Study of linear and non-linear analyses of rayleigh-benard chandrasekhar convection in micropolar fluid with saturated porous medium
Thermal instability of Chandrasekhar convection in a micropolar fluid, saturated porous layer is being investigated in this study. The model is confined between two horizon- tal plates of infinite length and separated by a fixed distance. A uniform temperature gradient is provided at the lower plate, while the upper plate is cooled. The study is analysed for both linear as well as non-linear cases to understand the stability, transfer of heat and mass within the model. The study is carried out in extending the model for Rayleigh-Benard and double diffusive convection with external constraints such as in-ternal heat, concentration source, gravity modulation, temperature modulation, coupled cross diffusion and throughflow. The outcome of the study is discussed in detail and presented pictorially through graphs. Linear and Non-linear Analyses of Double Diffusive Chandrasekhar Convection with Heat and Concentration Source in Micropolar Fluid with Saturated Porous Media under Gravity Modulation. A thermosolutal convective study is carried out in the presence of externally imposed magnetic field and gravity modulation together with heat and concentration source in a micropolar fluid. This problem is analysed for both linear and non-linear cases by as- suming the strength of heat and concentration source same. The expression for critical thermal Rayleigh number and correction thermal Rayleigh number are obtained using regular perturbation method to understand the stability of problem. The transfer of heat and mass transport is investigated by deriving the eighth order Lorentz equation. It is found that internal Rayleigh number and Darcy number speeds up the onset of instabil-ity while the coupling parameter and Chandrasekhar number has a reverse effect. Also, the transfer of mass is more compared to the transfer of heat. Linear and Non-linear Analyses of Double Diffusive Chandrasekhar Convection Coupled with Cross-diffusion in Micropolar Fluid over Saturated Porous Medium The problem aims to find the effects of coupled cross-diffusion in a micropolar fluid over a porous medium, subjected to double-diffusive-Chandrasekhar convection. The usual stability analysis has been employed to determine the critical thermal Rayleigh number. Non-linear analysis is carried out by deriving the Lorentz equations using trun- cated Fourier series representation. Heat and Mass transport are quantified by Nusselt and Sherwood number respectively. Analysis related to the effect of various parameter are plotted and the result for the same are interpreted. As Dufour parameter increases, the diffusion of heat and solute takes place which increases the temperature difference and thereby delays the onset of convection by making the system stable. It is observed from the results that Dufour parameter and Soret parameter have opposite influence on the stability of the problem. Linear and Non-linear Analyses of Throughflow Effect on the Onset of Rayleigh-Benard-Chandrasekhar Convection in Micropolar Fluid with Porous Medium. The Rayleigh-Benard convection over a porous medium saturated with micropolar fluid is simulated via externally imposed magnetic effect. The stability of the system is ex- amined using linear analysis by the method of normal mode. The rate of heat and mass transport within the system is examined by deriving sixth order Lorentz equation using non-linear analysis. It is observed that by regulating the throughflow effect, the con- vection of the system can be controlled. Also, the pro-gravity and anti-gravity cases has a stabilizing effect on the system. From mathematical calculation, it can be seen that heat transfer rate is same for both pro-gravity and anti-gravity cases, because of the symmetric nature of the boundaries considered. Linear and Non-linear Analyses on the Effect of Time Periodic Boundary Temper- ature and Internal Heat Source in a Micropolar Fluid on the Onset of Rayleigh- Benard-Chandrasekhar Convection with Porous Medium The impact of temperature modulation at the boundaries over a surface containing voids that is soaked in micropolar fluid is investigated to understand the thermal instability of the convection exposed to magnetic effect and internal heating of the system. A small amplitude of perturbation is given to the system to analyse the thermal instability by performing a linear study through the method of regular perturbation, which yields Rayleigh number for unmodulated and modulated system. Three cases of study is car-ried out to inspect the vibrating temperature field at the boundaries, namely symmetric case where the temperature is modulated in-phase, asymmetric case where the temper-ature is modulated out-phase and the case where only the bottom wall temperature is modulated. The non-linear analysis is employed to find the heat in the system, using Lorentz model. The outcome of the study conveys that sub critical motion occurs dur- ing in-phase modulation while the out-phase modulation leads to a more stable system. Moreover, internal Rayleigh number hastens the onset of convection. -
Study of Low-Mass Stars and Brown Dwarfs In Star Forming Regions of Diverse Environments
The formation and evolution of low-mass stars and brown dwarfs is an intricate process orchestrated by the environmental conditions in which they form. As a natural byproduct of this process, circumstellar disks are formed, whose dynamic relationship with the environment plays a pivotal role in determining the fate of the star and the timescale for planet formation. While low-mass stars are a dominant product of the star formation process, brown dwarfs occupy a unique position, bridging the gap between newlinelow-mass stars and planets. In this thesis, we have examined the low-mass stars and brown dwarfs in young clusters located at different distances with diverse UV radiation felds and stellar densities to decode the role of environment in shaping the IMF, its inand#64258;uence on disk evolution and to understand the formation of brown dwarfs. We have targeted three young star forming regions for the newlinestudy namely and#963; Orionis, twin clusters IC 1848-East and West, and IC 1396 using deep multi-wavelength photometry as well as near-IR spectroscopy with 4m and 10m class facilities. For the and#963; Orionis cluster we used deep CFHT-WIRCAM near-IR data and the novel water-band photometry technique along with Gaia DR3 to identify the candidate low-mass members. Spectroscopic follow-up observations conducted with IRTF-SpeX validated the selection of the candidates by this technique with a 100% effcacy. We then compiled a comprehensive membership catalog for a mass range and#8764;19-0.004 Mand#8857;. The form of the stellar-substellar IMF was found to be consistent with other nearby star forming regions suggesting a lack of signifcant environmental inand#64258;uence. Further, we analysed the evolutionary class of the members based on the mid-IR slope of the SED to study their disk properties. We estimated the disk fraction of the low-mass sources to be consistent with other star form ing regions considering the age of the cluster. This showed that in this region, external photoevaporation does not play a major role in the inner disk evolution. -
Study of magnetoconvection with maxwell cattaneo law
This thesis deals with the study of Rayleigh-Bard-convection in a Newtonian fluid and micropolar fluid by replacing the classical Fourier law by non-classical Maxwell-Cattaneo heat flux law. The effects of second sound, non-uniform basic temperature gradients, suctioninjection-combination, temperature modulation and gravity modulation in newlinepresence of external constraints like magnetic field and rotation are studied. newlineThe problems investigated in this thesis throw light on externally controlled convection in Newtonian and micropolar fluids in the presence of Maxwell-Cattaneo law. The problems investigated in this thesis deal newlinewith practical problems with very large heat fluxes and/or short time duration. With this motivation, we investigate in this thesis five problems and their summary is given below. (i) Effects of Coriolis force and non-uniform basic temperature gradients on the onset of Rayleigh-Bard-Chandrasekhar newlineconvection with Maxwell-Cattaneo law The effect of non-uniform temperature gradient on RayleighBard-Chandrasekhar convection in a rotating Newtonian fluid with Maxwell-Cattaneo law is studied using the Galerkin technique. The eigenvalues is obtained for free-free, rigid-free and rigid-rigid velocity boundary combinations with isothermal and adiabatic boundaries. A linear stability analysis is performed. The influence of various parameters on the onset of convection has been analyzed. One linear and five non-linear temperature profiles are considered and their comparative influence on onset is discussed. It is found that the results are noteworthy at short times and the critical eigenvalues are less than the classical ones. It is shown that the system having magnetic field will delay in the onset newlineof instability. In general, it is observed that step function and inverted parabolic temperature profile are the most destabilizing and stabilizing profiles. -
Study of Rayleigh-Benard Dynamical System Involving Newtonian and Nanofluids in Rectangular and Cylindrical Enclosures
Analyzing and#64258;uid and#64258;ow behavior in the presence of temperature gradients subjected to internal and external forces in diand#64256;erent geometries is essential for optimization newlineprocesses for various engineering applications, guiding the design of more efcient thermal systems. This thesis focuses on investigating the Rayleigh-Bard convection problems occupying rectangular and cylindrical enclosures. The linear and newlineweakly nonlinear analyses are carried out that reveal the results on regular convection, heat transport and chaotic motion for each of the problems. Steady and newlineunsteady states of the Rayleigh-Bard system are studied using the Lorenz model. The dynamical system is investigated to look for possible chaotic motion. Fluid systems can exhibit chaotic behavior, and understanding the chaotic nature of these and#64258;ows is essential for accurate predictions of their evolution over time. In view of this, the regular, chaotic, and periodic natures of the dynamical system is thoroughly analyzed. Further, the inand#64258;uence of various parameters on the indicators of chaos is explored. Additionally, the thermal performance of the system is looked into by introducing nanoparticles/nanotubes into the base and#64258;uid. newlineWith the aformentioned motivation, we now present the abstract of each of the problems considered in this thesis one-by-one. 1. Impact of boundary conditions on Rayleigh-Bard convection: stability, heat transfer and chaos In the frst problem of the thesis, discussed in Chapter 3, a comparison is made newlinebetween the results of Rayleigh-Bard convection problem for diand#64256;erent boundary combinations, namely, rigid-rigid-isothermal, rigid-free-isothermal and free-free isothermal boundaries for a Newtonian and#64258;uid. The linear and weakly-nonlinear analyses reveal that the onset of regular and chaotic motions in the case of rigid-freeisothermal boundaries happens later than that of free-free isothermal boundaries but earlier than rigid-rigid-isothermal boundaries.+ -
Study of single and two component convection in micropolar liquid
In this thesis, we study linear and non-linear analysis of RayleighBard and double diffusive convection in a micropolar liquid. The effect of non-uniform basic temperature gradient, non-uniform basic concentration gradient, temperature modulation at the boundary and gravity modulation are studied. newlineThe problem investigated in this thesis through a light on externally controlled internal convection in a micropolar liquid. The problems investigated in this thesis have possible application in geophysics, newlineastrophysics, oceanography engineering and in space situations with gjitter connected with gravity stimulation study. With this motivation, we investigate in this thesis four problems and their summary is given below one by one. (i) EFFECT OF GRAVITY MODULATION ON HEAT TRANSFER BY RAYLEIGH-BARD CONVECTION IN A MICROPOLAR LIQUID newlineThe vertical oscillation, or g-jitter or gravity modulation, is known to appear in the situation of the satellite. In the laboratory, Rayleigh-Bard system subjected to time-periodic vertical oscillations may be useful in regulating the onset of convection and heat transfer. This aspect is also in newlinefocus in the thesis. In this problem the effect of time-periodic body force or grtavity modulation on the onset of Rayleigh-Bard convection in a micropolar liquid is investigated. The linear and non-linear analyses are performed. The linear theory is based on normal mode analysis and perturbation method. The expression for correction Rayleigh number is obtained as a function of frequency of modulation and other micropolar liquid parameters. The non-linear analysis is based on the truncated Fourier series representation. The resulting non-autonomous Lorenzvii model is solved numerically to quantify the heat transport. It is observed that the gravity modulation leads to delayed convection and reduced heat newlinetransfer. (ii) LINEAR AND WEAKLY NON- LINEAR STABILITY ANALYSIS OF DOUBLE-DIFFUSIVE CONVECTION IN A MICROPOLAR LIQUID. -
Study of substituion effectson structure and properties of high temperature superconductors and isostructure compounds
The thesis mainly describes the investigation of the structural formation of higher order members of bismuth system of superconductors Bi1.6sPb0.35Sr2CazCu4Oy (n = 4, 2234 phase), Bi1.6sPb0.35Sr2Ca4CusOy (n = 5, 2245 phase) and Bi1.65Pb0.35Sr2CasCu,Oy (n = 9, 2289 phase). The samples were synthesized by solid state reaction technique. Micro-structural and morphological features of the synthesized samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDS). The XRD pattern of all the samples revealed the presence of Bismuth 2212 and 2223 phases of which 2223 phase was found to be the predominant. Superconducting transition temperature (Tc) of the samples measured by self-inductance method and dc four probe method showed Tc value around 110 K. There was no signature of the formation of 2234, 2245 or 2289 phases in this investigation. newlineFormation of Bi-2245 compound was further investigated by preparing the sample in a new matrix route. The Tc on set of this sample was found to be 127 K which was the highest reported ever in bismuth system superconductors. The complete replacement of copper by nickel in bismuth system superconductor Bi2SraCu06 (2201) was ttempted by preparing the sample in air by solid state reaction method under open and closed environment. Morphological and microstructural features of the synthesized sample Bi2Sr2Ni0g was investigated by X-ray diffraction, SEM and EDAX. The analysis of X-ray diffraction pattern revealed that nickel can replace copper completely and form a single phase Bi2Sr2Ni06 only when prepared in a closed environment in air. This phase formation of BizSr2NiOo was reported first time. -
Study of the diffuse ultraviolet background radiation at high galactic latitudes
The diffuse background radiation is observed throughout the whole sky and across every wavelength of the electromagnetic spectrum. The study of this background is of great importance as it contains photons coming from a va- riety of astrophysical environments, traveling over the time scales of a few hundred light years to the age of the universe itself. After the discovery of the cosmic microwave background, the diffuse sky in all the other wave- lengths was studied with great interest as they could provide useful insights into the formation history of the universe. In the work outlined in this the- sis, I will be describing this diffuse background radiation observed in the ultraviolet (UV) region. Over more than three decades of observations of the diffuse sky in the UV has revealed our lack of understanding of all the components that con- tribute to the observed background sky in this wavelength region. Initial studies arrived at controversial conclusions with one group suggesting that most of the observed diffuse surface brightness is due to the dust scat- tered starlight while another group suggested contribution from an exotic component along with the dust scattered component. We will explore this background sky in detail by trying to identify individual components and quantify its contribution at various regions in the sky. We have started our analysis at the Galactic pole regions with |b| > 80 using the data from Galaxy Evolution Explorer (GALEX) in the ultravio- let band. A major Galactic component of the diffuse sky in the UV is the starlight scattered by interstellar dust (also called Diffuse Galactic Light: DGL). We chose to study the Galactic poles due to the low dust environ- ment in these regions and easier modeling of the DGL component. We found consistent offsets in the UV data at a level of 230 290 photons s?1 cm?2 sr?1 1 (hereafter photon units) in the far-UV (FUV: 1539 and 480 580 photon units in the near-UV (NUV: 2316 when the UV surface brightness was compared with Galactic tracers like E(B-V) and the infrared surface brightness. These offsets represent the UV brightness at zero column densities. Part of this offset comes from the extragalactic background light (EBL) originating in background galaxies, Quasi-Stellar Objects (QSOs), etc. After careful estimation of this EBL component, we found a residual UV surface brightness of about 120 180 photon units in the FUV and 300 400 photon units in the NUV. The DGL component came to be about 120 photon units in these regions. We also found evidence for contribution from molecular hydrogen fluorescence at a column density of log NH > 20.2 (NH is in cm?2). We conclude that this contribution from H2 is from the cirrus features present at high Galactic latitudes. We further confirmed our findings at the north and south Galactic poles by studying the region between latitudes 70< b < 80 where we found similar offsets and the fluorescence contribution from H2 at the same levels as in the NGP. We proposed a possible contribution to the observed residual surface brightness coming from Hawking evaporation of Primordial Black Holes. But the level of this radiation was not sufficient to account for the entirety of the observed excess. The failure of this explanation only further deepens the mystery of the source of the excess surface brightness of the UV sky. -
Study of Three-Dimensional Mapping of Interstellar Extinction in Milky Way Galaxy
The Ultraviolet Imaging Telescope (UVIT) is scheduled to be launched as a part of the ASTROSAT satellite. As part of the mission planning for the instrument we have studied the efficacy of UVIT observations for interstellar extinction measurements. We find that in the best case scenario, the UVIT can measure the reddening to an accuracy of about 0.02 magnitudes, which combined with the derived distances to the stars, will enable us to model the three-dimensional distribution of extinction in our Galaxy. The knowledge of the distribution of the ISM will then be used to study distant objects, affected by it. This work points the way to further refining the UVIT mission plan to best satisfy different science studies. newlineWe report here on our plans to use data from the Ultraviolet Imaging Telescope (UVIT) aboard the ASTROSAT mission to probe the extinction across the entire sky. This mission has been in develonment since 2000 (Agrawal 2001) and is expected to be launched on a Polar Satellite Launch Vehicle (PSLV) rocket by the Indian Space Research Organization (ISRO) in 2013. The UVIT instrument is being developed at the Indian Institute of Astrophysics (IIA) and includes three telescopes, two in the ultraviolet (FUV and NUV) and one in the visible, each including a filter wheel with a number of different filters (Kumar et al. 2012). We have run a series of simulations to determine which filters are best suited for our purpose and will use these results in planning our observations with the UVIT. -
Study of triple diffusive convection in non newtonian liquids
This thesis presents the study of triple diffusive convection in two nonNewtonian liquids couple stress liquid and viscoelastic liquid of type Oldroyd-B in the presence of external constraints like rotation, gravity modulation and temperature modulation. Linear stability analysis provides the stability condition of stationary and oscillatory convection and the resultant eigen function describes the newlineconvective flow. However, linear analysis can neither help to examine the rate newlineof heat and mass transfer nor provides information on the convection newlineamplitudes. Therefore, it is also important to do nonlinear analysis. In view of newlinethis, all the problems considered in this thesis are studied for both linear and newlinenonlinear cases. The eigen value arising in the linear case for the problems newlinewithout modulation is solved by normal mode technique whereas for the problems with modulation is solved by perturbation method by adopting Venezian approach. The nonlinear study is done by using Ginzburg Landau newlinemodel for the problems with couple stress liquid whereas the nonlinear study is done by truncated representation of Fourier series by Lorenz model for the problems with viscoelastic Oldroyd-B liquid. The present study has wide range of applications in material processing, solidification of alloys, underground spreading of chemical pollutants, petroleum reservoirs, cooling of electronic devices, thermal insulation newlinematerial, crystal growth, transport of chemical substances, solar receivers, newlineinjection moulding, chemical industries, nuclear industries, bioengineering, newlineoceanography, meteorology, astrophysics, geophysics and so on. The extensive description of wide-ranging applications of triple diffusive convection in non-Newtonian liquids is accountable for the motivation of this thesis. The following four problems are carried out in this thesis: (i) EFFECT OF ROTATION ON TRIPLE DIFFUSIVE CONVECTION IN COUPLE STRESS LIQUID The effect of rotation on triple diffusive convection in couple newlinestress liquid is considered. -
Study on Graphs Associated with Groups
In this dissertation, the notions of non-inverse graphs, order sum graphs and coset newlinecomponent graphs associated with groups are introduced. These graphs are simple graphs whose vertices are the elements of the group and the adjacency between the vertices depends on certain properties of the group concerned. Vertices belonging to non-inverse graphs are adjacent if they are not inverses of each other in the group. The vertices in order sum graphs are adjacent if the sum of their orders is strictly greater than the order of the group. The vertices belonging to the coset component graphs are adjacent if their left cosets or right cosets of the subgroups of groups are equal. These algebraic graphs are studied in detail in terms of their structural characteristics, parametric properties and spectral properties. Various characterisations of these graphs are obtained in the study concerned. These notions are further extended to the concept of signed graphs and domination. Properties of signed graphs such as balance, clusterability, consistency, sign-compatibility and so on are investigated for these algebraic signed graphs. The relations between various types of domination are obtained for non-inverse graphs, order sum graphs, complement and line graphs of order sum graphs. -
Study on nonlinear convective flow of hybrid nanofluids in an annulus
In this modern fluid field technology, hybrid nanofluids are of great interest to researchers due to their improved thermal properties which provide a superior improvement in heat transfer compared to nanofluids. The hybrid nanofluid flow in an annular geometry finds its relevance in engineering and material manufacturing processes such as heat exchangers, nuclear power plants, hot rolling, and heat storage systems due to their high heat transport rate. Since these devices are operated at moderate and very high temperatures adopting linear Boussinesq approximation becomes inappropriate. Owing to this, the present research is devoted to the study of flow, heat, and mass transport characteristics of hybrid nanofluid in an annulus including the effects of radial/transversal magnetic field, thermal radiation, exponential space-related heat source, uniform/non-uniform heat source and variable thermophysical properties under the nonlinear Boussinesq approximation. The fundamental equations are obtained from the laws of conservation of mass, momentum, and energy. The dimensionless governing nonlinear equations are treated analytically/numerically. Further, the sensitivity analysis using response surface methodology (RSM) is performed to enhance the understanding of heat and mass transport behavior. The significance of various flow parameters (involving in the problem) on the flow structure, thermal model, concentration field, heat, and mass transport rate are analysed through 2D/3D-surface plots and discussed quantitatively. -
Subjectivity Analysis Using Social Opinion on Stress and Strain During Covid-19 Pandemic
The psychological health of several people across the globe has been under great risk newlineas a result of the COVID-19 pandemic that shook the entire world. The ubiquitous newlinepandemic had created a tectonic shift in everyone s life. The lives of people have newlineundergone a severe transition with strict measures like lockdown and social distancing newlineimposed by governments of several countries to stop the spread of the viral infections. newlineCoping through the adverse situation has been quite onerous causing stress among the people. The transition from normal life to a life filled with several restrictions has newlinebeen stressful and strenuous. A state of emotionally or physically being tensed can be newlineconsidered as stress. Stress can cause frustration, depression, nervousness and other mental health issues. Stress also leads to strain. Social media networking sites like newlineX(Earlier Twitter) and Facebook have emerged to become popular. During the times of lockdown and social distancing the social media networking sites have been a great newlineplatform for expressing opinions, exchange of ideas and thoughts. People have expressed their stressful situations and coping mechanisms through tweets , Facebook newlineposts and several other social media sites during the pandemic. The underlying stress newlineand strain of a person can be analyzed through the posts shared by the person through the social media sites. Early detection of the prevalence of the stress and strain is important, as medical help can be sought quickly and the person affected can be back to normalcy. Subjectivity analysis is the study that deals with analyzing the emotions, feelings, attitudes and polarity of opinions considering any subject matter. newlineThe present research focuses on subjectivity analysis through social opinion mining newlineduring the COVID-19 pandemic. Social opinion mining incorporates Natural Language Processing and Computational Linguistics that identifies the subjectivity across the posts of social media. -
Sum Signed Graph
A sum signed graph S = (G, f, and#963;) is a signed graph of the underlying graph G where f : V (G) and#8722;and#8594; {1, 2, . . . , | V (G) |} is a bijective function and and#963; : E(G) and#8722;and#8594; {+, and#8722;} is newlinea mapping such that and#963;(uv) = +, whenever f(u) + f(v) and#8804; n and and#963;(uv) = and#8722;, whenever f(u) + f(v) gt n. The minimum number of negative and positive edges among all the sum signed labelings of G is known as rna and rna complement number respectively. The maximum number of positive edges among all the sum signed labelings of G is known as adhika number. The set X and#8838; V (G) is said to be a s - dominating of a signed graph whenever X is a dominating set and there exists exactly s number of negative edges between X and its complement. The minimum cardinality of such a dominating set over all signed graphs of the graph G is called an s - domination number. newlineIn the present study, we initiate the study of a new labeling in signed graphs namely, newlinesum signed labeling. The characteristics of sum signed graphs and the bound of rna number of in terms of the number of vertices in the underlying graph are explored by examining the rna number of different graphs. The properties of signed graphs such as negating and balancing is analyzed. The relation between rna number and rna complement number is established. The connection of sum signed labeling with parity signed labeling and cordial labeling is discussed. The absolute cordial condition for graphs satisfying sum signed labeling is examined. The concept of s - domination was also introduced during this period of study. The s domination in both the positive and negative homogeneous signed graph is investigated for each value of s. The properties of s domination in sum signed graphs are also analyzed. The s - domination number for specifc values of s is investigated for various graphs. The maximum value of s for a graph for which the s - domination will exist is discussed. -
Suppression and redfinition of self in the selct novels of Toni Morrison and ALice Walker
Literature is a mirror held onto the society that reflects the culture, history and socio-political issues of specific periods. Books have the uniqueness of transforming lives by weaving characters, to whom we are able to relate their trials, tribulations and achievements become our own. Although confined to the Afro-American milieu, Alice Walker s The Color Purple and Toni Morrison s The Bluest Eye, Sula and Beloved raises issues and concerns that are universal to women across the globe. These writers try to lend voice to an otherwise marginalized and newlinesuppressed group of women, who have been denied a dignified existence. This research, through the methodology of critical analysis and interpretation of texts, tries to understand the concept of self, from the western and eastern perspectives. In the due process, the various factors that contribute to the formation of an individual s self are also identified. Through an analysis of the newlinefemale protagonists in the works of Morrison and Walker, this study examines how it is possible for a woman to progress from the margins to a position that is central, from object to subject. newlineMost often, women are not even conscious that they too have an individuality of their own and need to lead a dignified life. Having got so habituated to oppression, it has almost become a way of life for them. They need to be conscious and aware of the fact that they have to create a space of their own, without compromising on their individuality and dignity. When they fail to do this,they just stagnate and become mere pawns in the hands of men and tend to get exploited. Most of newlinethe female protagonists discussed in this study, go through this phase and are unable to extricat themselves from the traumatized conditions that engulf them. newlineThis study clearly focuses on how women need to be conscious of what is happening to them and realize that they are being deprived of their individuality and dignity. -
Sustainable tourism development through community based waste management in backwater destinations of kerala
According to the United States Environmental Protection Agency, (2002) solid waste newlinemanagement is a great challenge in many tourist destinations because improperly managed solid waste can threaten the environment as well as the life of the local community. Sewage waste and plastic material from tourism houseboats are increasing the pollution in the backwaters of south Kerala. These days it is not completely proper for touristic activities because of their physical and morphological attributes. This can lead to unsustainable negative impact on the backwater (Iskander and El 2014).Therefore this study was seeking to understand the influence of community based waste management towards the sustainable tourism development in the backwaters of south Kerala. The research adopted a descriptive research design. The study consists of three newlinecategories of stakeholders. Public sector, Private sector, and Local community. Public Sector stakeholders include Hotel Officials, Resorts officials and houseboat officials. Private sector stakeholder includes the government representative of concerned backwater destination. Descriptive statistics, ANOVA, Confirmatory factor analysis (CFA), SEM Modelling are the various statistical techniques used in this study. Cross-case analysis was used to analyse newlinethe qualitative aspects of the research study. This study also develops and test a community based waste management model for newlinesustainable tourism development and considered the influence of factors on community support, community involvement, perceived benefits and perceived cost. The structural model indicates that increasing perceived benefits and decreasing perceived cost from backwater tourism would help to enhance community involvement and support for newlinesustainable tourism development in the backwaters of south Kerala. -
Sustainable tourism management : Issues and challenges of eco wildlife resorts in karnataka
Sustainable tourism principles comprise of visitor satisfaction, the economic newlinesustainability of the industry, environment conservation, socio-cultural and economic newlinedevelopment of local communities. The tourism industry has to consider all these elements while developing any form of tourism for its long-term sustainability. Eco and wildlife resorts are one of the prominent and attractive segments of the accommodation sector. It has a major implication for implementing sustainable tourism practices in their daily operations since they are set close to nature and reside in pristine wildlife regions. It is inevitable for eco and wildlife tourism, to consider all newlinethe elements of sustainable tourism practices and to implement it in their day to day newlineactivities. At the same time, they might have to face issues and challenges in newlineimplementing sustainable practices. So, the main objective of the research is to newlineunderstand operational issues and challenges of eco and wildlife resorts in achieving newlinesustainable tourism principles. The purpose of the study is to investigate the issues and challenges faced by eco and wildlife resorts in implementing sustainable tourism practices and understanding the indicators used by the resorts to measure their sustainable tourism newlinepractices. The scope of the study covers selected eco and wildlife resorts in Karnataka because most eco and wildlife reserve areas are shared by pristine natural areas and are located near villages. The targeted respondents of the study are eco and wildlife resort managers and visitors of eco and wildlife resorts. Based on purposive sampling, 30 resorts are selected for the study, and 410 visitors are selected based on convenient sampling technique. The study employs a mixed-method research design. newlineTriangulation design is used in the study. The study adopted a tool to identify the newlinesustainable tourism indicators used by the resorts to measuring their sustainable newlinetourism practices. -
Symbols as Photographic Texts in the Travel Narratives of Paulo Coelho
Brazilian writer Paulo Coelho de Souzas The Pilgrimage, The Alchemist, Zahir, Aleph and Hippie are known for using literary symbols to describe journeys where the protagonists travel to different destinations searching for something valuable. The author resorted to multiple religions, cultures, traditions, mythologies and folklore to derive inspiration to use those symbols and frame his philosophical thoughts. As the symbols used by Coelho can be deciphered in whatever way subject to personal interpretations, one way of understanding them can be from the perspectives of their already established meanings in religions, cultures, traditions, mythologies and folklore. Such a way of understanding limits the possible meanings that can be derived from those symbols. Moreover, another sign system is known for conveying limited meanings, usually called photographs. Though absolute material accuracy is seen as the hallmark of photography, the meaning of photographs also depends upon their interpretations, and photographic truth is considered a myth. Still, photographs possess documentary properties and convey limited meanings to a large extent. This thesis studied the idea of photography, defining the same by understanding the historical developments in photography over time. Knowing the definition and properties of photographs, it looked at how photographs convey limited meanings and exhibit 'iconic' properties in general. After isolating and studying the literary symbols used by Coelho in the five travel narratives mentioned above using the Peircean model of semiotic analysis, the thesis concludes that symbols act as photographic texts to a certain limit in the five novels, as they tend to move towards becoming 'iconic' from 'symbolic' if understood from the perspectives of their existing meanings in religions, cultures, traditions,mythologies and folklore. -
Synergetic Effect of Metal Nanoparticle Embedded Graphene Membrane : A Novel Approach for Antimicrobial Filtration
Water, the elixir of life, holds a profound significance that extends far beyond its essential utility. It's not just a resource; it pulsates as the life force of our existence, intricately woven into the very fabric of our daily lives. Water is the silent force that shapes our world, from nurturing our health and sustaining social structures to fueling economic development and fostering the environment. However, the adequacy of potable water quality confronts adverse impacts stemming from inadequate wastewater treatment, escalating domestic and industrial waste, and the microbial contamination of surface water sources. Furthermore, climate change emerges as a pivotal factor intensifying the depletion of water levels in natural resources due to diminished rainfall. Reports project that, by 2025, two-thirds of global population might contend with water scarcity. Given the persistence of current scenario, there exists a notable potential for significant conflicts among nations stemming from water scarcity. However, such a predicament can be mitigated through proactive measures, including the preservation of natural resources and the implementation of advanced technologies to recover fresh water from contaminated sources. Advanced technologies for the purification of contaminated water encompass sedimentation, precipitation, filtration, and ion exchange, which can effectively extract clean water from diverse impurities. Notably, membrane-based purification has gained prominence in recent years, owing to its cost- effectiveness and energy-saving attributes. Carbon-based nanomaterials, including carbon nanotubes,fullerenes and graphene have garnered considerable attention in recent research studies, particularly in the realm of membrane applications. Within this, membranes fabricated by carbon nanotubes (CNT) stand out, showcasing exceptional filtering properties attributed to their tubular carbon structure. However, the cost-effectiveness and ease of synthesis impediments pose significant challenges, acting as bottlenecks for their widespread application in water purification. Consequently, graphene-based membranes emerge as a promising alternative to CNT membranes, demonstrating selective separation of ions and molecules. Specifically, membranes derived from graphene oxide (GO) and reduced graphene oxide (rGO) exhibit superior filtering capabilities compared to ceramic and polymeric counterparts, owing to their layered structure featuring tunable nanochannels, hydrophilic or hydrophobic nature, and commendable mechanical resilience. Graphene oxide solution synthesis has been done using Hummer's method, followed by fabrication of high-quality membranes through vacuum filtration techniques. Current work emphasis on recognizing the pivotal influence of membrane thickness on both water flux and dye rejection, meticulous optimization of filtration properties by producing graphene oxide (GO) membranes at various concentrations. Furthermore, reduction of graphene oxide through the hydrothermal method, enabling a comprehensive comparative analysis of water flux and rejection between graphene oxide (GO) and reduced graphene oxide (rGO) membranes was carried out. In our investigation, the results unequivocally validate that the GO 500 sample exhibits optimized filtration properties. Furthermore, the reduced graphene oxide (rGO) variant surpasses graphene oxide (GO) in terms of filtration efficacy, demonstrating superior filtering properties. It is noteworthy to highlight that reduced graphene oxide (rGO) exhibits less antibacterial properties compared to graphene oxide (GO). The disinfection capability of the membrane is pivotal in ensuring the recovery of pure water. To bolster the antibacterial features of GO, we have undertaken an enhancement strategy by incorporating silver nanoparticles. Silver nanoparticle, showcases multifaceted properties including surface plasmon resonance and unique morphologies, which contribute significantly to the inactivation of bacteria. The conducted studies reveal that membranes incorporating graphene oxide with silver (GO-Ag) exhibit remarkable antibacterial properties against both gram-positive and gram-negative bacteria. Additionally, these membranes demonstrate appreciable filtration capabilities and exhibit effective antifouling properties, further emphasizing their potential for advanced applications in water purification systems. Fouling is a significant challenge in membrane technology, as the continuous passage of contaminants results in the formation of layers on membrane surface, thereby diminishing its filtration efficiency. Despite the antifouling properties exhibited by GO- Ag membranes, there exists further improvement in enhancing performance and extending the membrane's lifespan. To address this, we have undertaken a reduction of graphene oxide and incorporated silver nanoparticles, aiming to augment the antifouling properties and overall efficacy of membrane. The conclusive findings indicate that fine-tuned membrane exhibits remarkable antibacterial properties, superior filtration capabilities, and a minimal irreversible fouling ratio. These outcomes provide confirmation that the fabricated membranes stand as potential materials for water purification applications, showcasing a well-rounded set of properties essential for effective and sustainable water treatment.