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Investigating structure and spectral energy distribution of galaxies using uvit and multi-wavelength archival data
This thesis deals with the multi-wavelength investigation of the different aspects of galaxy formation and evolution. The first part of this thesis deals with the studies on the characteristics of the in-orbit performance of the Ultraviolet Imaging Telescope (UVIT) on-board AstroSat. We have written a UVIT pipeline (JUDE ) to convert the Level 1 data from the Indian Space Science Data Centre (ISSDC) into scientifically useful photon lists and images. We have also performed an independent calibration of the FUV and NUV channels of the UVIT using JUDE. We found that the photometric sensitivity is about 35% that of the Galaxy Evolution Explorer (GALEX ) in the FUV broadband filter, and about the same as GALEX in the NUV broadband filter. The point spread function (PSF) of the instrument is of the order of 1.2 1.6and#8242;and#8242;. We found that the performance is close to that expected from the ground-based calibrations. We studied the recent star formation in the nearby face-on spiral galaxy NGC 2336 using the UVIT imaging. We have identified 78 bright star-forming complexes in the disk and derived their positions and estimated their properties such as luminosities, sizes, star formation rates (SFRs), colors, and ages. The FUV-NUV colors of the complexes are found to be redder in the inner region of the galaxy and become progressively bluer as the radius increases. The last part of this thesis is devoted to a model-based study of galaxies using physically motivated Code Investigating Galaxy Emission (CIGALE) package. We have studied 10,000 galaxies from GALEX SDSS merged catalog using CIGALE and estimated their properties such as stellar masses, SFRs, stellar populations, dust luminosities etc. We have classified this set of galaxies into the star-forming, intermediate and quiescent type of galaxies based on their specific SFR. We also studied the properties of dust-lane spheroidal galaxies (DLSGs) drawn from the multi-wavelength archival data in 18 bands from FUV to FIR using GALEX, SDSS, 2MASS, WISE, and AKARI surveys. -
Topological Indices Based on Distance Labeling
This thesis explores the prospect of combining two prime branches of graph theory, newlineviz., topological indices and graph labeling, specifcally radio labeling. The majority newlineof the work includes the topological radio indices of graphs and their properties. Topological indices are numerical values associated with graphs and invariant with graph isomorphisms. Apart from Topological Radio Indices, it provides some additions to the eccentricity-based topological indices. newlineRadio labeling or radio coloring, c, is assigned to a graph G such that the label difference between any two vertices must be greater than diam(G)+ 1 and#8722; d(u,v). Optimum radio labeling is the foundation for defning Topological radio indices. Labeling whose span is the radio number of the graph and which leads to the minimum value of the index newlineis considered the optimum radio labeling. The topological radio indices and coindices newlineare defned and are found out for some special classes of graphs, including gear graphs, newlinewheel graphs, and star graphs. The bounds for the frst, second and third Zagreb radio indices have been established and characterized for the classes of graphs for which the bound is sharp. Furthermore, newlinespecifc relationships between Zagreb radio indices and coindices are established concerning different parameters of the graph. newlineThe idea of consecutive radio labeling is explicitly studied. We have characterized the newlinegraphs with diameter 2 admitting consecutive radio labeling. We have studied the properties of graphs admitting consecutive radio labeling and stated the necessary and suffcient conditions for a graph to follow consecutive radio labeling. The study extended to eccentricity-based topological indices, viz., the forgotten eccentricity indices. The maximum d(u,v) for all v in V(G) is the eccentricity of the vertex u in G. This work also investigates eccentricity-based coindices and some of their properties. newlineApart from this, some uniquely radio colorable graphs are examined and characterized. -
Cost Effective Synthesis of Carbon Nanoparticles and Exploring the Fluorescence and Electrochemical Applications
Graphene-based materials and composites for sensing are a fascinating field in material science research that is experiencing rapid advancement. But the applications of graphene-based materials were often hampered by their high production cost, low yield, expensive and scarce precursors, harmful processing techniques, etc. Coal is made up of islands of nanometer-sized crystalline carbon domains linked by a 3D network of amorphous aliphatic carbon and polymerized aromatic hydrocarbons that can be extracted using mild oxidizing agents. In this context, the present study reports the successful usage of low-grade coal, lignite as an ideal precursor for the production of carbon nanostructures for various sensing applications. This research is divided into three parts where value addition to coal is being done along with finding solutions to three major environmental issues: fluorescence sensing of copper ion; noninvasive glucose fluorescence sensing; simultaneous electrochemical sensing of heavy newlinemetal ions cadmium and lead. In the first study, carbon nanostructures were synthesized from lignite by a simple, scalable, and economical technique and the as-prepared carbon nanostructures, namely LC1, LC2 and LC3, demonstrated excellent fluorescence characteristics. LC3 exhibited remarkable copper ion sensing with a dual linear range with limits of detection (LOD) as low as 1.32 pM and 2.35 pM, with limits of quantification (LOQ) 4 pM and 7.14 pM respectively. The accuracy of the manufactured sensor was shown by the recovery rates of copper ions, which varied from 98.18% to 101.2% with Relative newlineStandard Deviations (RSDs) below 0.4%. The results are captivating, implying that newlinethese lignite derived carbon nanostructures could be employed to efficiently and newlineeconomically detect low concentrations of copper ions in water. In the second study, carbon nanoribbons and nanosheets with superior fluorescence were synthesized from lignite, using a facile chemical oxidation process. -
Modified Metal Organic Frameworks for Electrocatalytic Water Splitting and Energy Storage Applications
Metal-organic frameworks (MOFs) are a class of crystalline material formed by the newlinecombination of metal ions/clusters along with organic linkers. This work is mainly based on newlinesynthesizing MOFs and their application in electrocatalytic water splitting and newlinesupercapacitors. The MOFs synthesized in the present work are Ni-Cu, {Mn-NiNH2(h2fipbb)}, Mn-MOF/rGO, and Sm-MOF/rGO/PANI using different ditopic and tritopic linkers. Using various characterization techniques, the formation of the synthesized MOFs is confirmed. The increasing use of fossil fuels now contributes to a number of environmental problems, including climate change and global warming. High-performance electrochemical energy storage devices are essential for portable electronics, electric cars, newlineand renewable energy storage medium, driving demand. MOFs are emerged as a promising newlinecontender for energy storage applications owing to their novel microstructures, atomically dispersed metal centers, and earth-abundant metal components. Electrochemical water splitting is a crucial approach in the pursuit of producing environmentally friendly fuels such newlineas H2 and O2, reducing our dependence on traditional fossil fuels while promoting newlinesustainable and clean energy sources. In order to produce hydrogen with the best efficiency and lowest cost, these MOFs are used. Electrochemical studies like cyclic voltammetry, galvanostatic charge discharge, and electrochemical impedance spectroscopy reveal that the prepared MOFs can be used as supercapacitors. Linear sweep voltammetry and Tafel plot determine the performance of these MOFs towards water splitting studies. Supercapacitors, which are electrochemical capacitors, are popular energy storage devices with quick charge rate, high power density, excellent rate capability, and outstanding life expectancy. -
After-Sale Service Failures and Their Influence on Customer Behaviour with Reference to Home Appliances
There are continuous technological advancements, and home appliance manufacturers have developed innovative products that make customer's life effortless. The increase in the purchasing power of the customers made the industry more competitive and put an extra burden on the manufacturers to adopt new technologies that help customers solve their problems and fulfil their needs. Firms face problems and challenges in the form of after-sale service failures. After-sale services are an integral part of home appliance products, and the companies can not avoid these while serving the customers. Although the after-service structure is rich in empirical studies on different service sectors like information technology, after-sale service failure, and consumer behaviour modelling in the home appliance have not been adequately investigated in Indian services. Previous researches have relied on understanding the services and their relation to either satisfaction or loyalty. Thus, they have been unable to disentangle the phenomenon of unfavourable reactions after an after-sale service failure from satisfaction and dissatisfaction. After-sale service is an essential component of customer behavioural outcomes. Therefore, businesses need to understand how after-sale service failures influence customer behaviour. Despite service superiority's importance, the home appliance industry lacks industry-specific, widely recognized instruments for after-sale service assessment. The primary goal of this study is to find major after-sale service failures and look at how these after-sale service failures affect customers, leading to unfavourable behavioural reactions. The study used a quantitative approach to understand the issue comprehensively. This research incorporated various after-sale service failure areas discussed and analyzed by previous research. It also discussed service theories and models (Expectancy Disconfirmation Paradigm, Justice Theory, Attribution Theory) related to failures and behaviours. However, this research focuses mainly on how these service failure areas lead to customer behavioural outcomes. Firstly, to know the major after-sale service failure areas, this study prepared the questionnaire based on the literature available on after-sale service failures and customers' reviews and their experience with the after-sale service of the home appliance companies. Data is collected from customers who have experienced after- sale service failures and their subsequent behaviour. The study analyzed the reasons for after-sale service failures, the types of failures that customers encounter, and the impact of these failures on customer behaviour, including their negative word of mouth, switching behaviour, willingness to recommend the brand etc. The findings of this study provided valuable insights into how businesses can improve their after-sale service and retain their customers. The study found seven major after-sale service failures that significantly impact customer behaviours. Unreasonable charges and policy clarity issues are the most significant service failures affecting customers, leading to negative behaviours. These findings show that different types of service failure elicit different reactions. The present study is one of the few empirical studies examining the links between service failures and actual behaviours in consumer durable after-sale service failures. -
Improvised process model for prediction of software development effort by integration of risk
Software development involves usage of a finite quantum of resources in accordance with the estimated effort and schedule. The newlineSoftware Development Lifecycle comprises activities pertaining to software engineering. The software engineering activities could be carried out using any of the various models available in practice. The newlineprocess of estimating size and effort accurately is vital in a software project since it could influence the success of the project. However, the realistic estimation of time and resources required for a project newlinecontinues to be a challenge. Risks exist in any software project, and hence Risk management is required to be considered across various processes throughout the project. The risks could be quantified by newlinearriving at the risk score based on the probability of occurrence of the risk and its impact. This research focused on the aspect that risk factors need to be considered in software effort estimation. A total of 503 newlinesoftware projects were considered, and from this dataset, projects which had risk score information were extracted and utilized for further analysis. This research work proposed an improvised effort estimation process by including risk scores in the standard estimation process. It also analysed the relationship existing between risk score in the project and other parameters considered in the effort estimation process. Regression analysis that was done on the dataset revealed an improvement in the model fitment by inclusion of risk score. An ensemble machine learning approach was utilized through deployment of Extreme Gradient Boosting algorithm. This algorithm was chosen newlineafter a model selection process by comparing various algorithmic models. The results indicated a better model fit by including risk as one of the parameters in the effort estimation process. A validation for the newlineproposed risk-integrated effort estimation model was done through responses from industry practitioners to a research instrument. -
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. -
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. -
Exploring Determinants of User Generated Context : A Consumer Behaviour Perspective
The advances in digital technology and the Internet have accelerated the growth of the online ecosystem. The ease of access to the Internet by the masses has ensured phenomenal expansion among online users. The past decade newlinewitnessed tremendous growth of online applications, platforms and apps that are newlinehelping to solve complex human needs. The online ecosystem itself witnessed newlinetremendous change, while static information sources have been replaced with dynamic ones that allow online users to participate in the system. The vast information society has transformed from being just the consumer of information to the participant in the generation of the information source. Business finds the exponential growth of online users and their active participation as an opportunity. Business benefits by sensing the market trends quickly in a better newlineway and take timely remedial actions. newlineDespite immense benefits offered by the online mode of business, many challenges have surfaced in recent times on account of ever-increasing technological sophistication and exponential growth of unique and similar newlineproduct offerings and associated reviews. The presence of many similar product offerings and associated reviews creates a technology-induced hurdle, with the potential to impair the rational thought process of consumers, who often search, scan and vote for only the top few reviews of selected products. This has the potential to make aged reviews continuously accumulate votes over time and newlineretain their near top position in the helpful review list, compared to recent quality newlinereviews. The current study applies statistically and scientifically derived newlinehelpfulness scores for ranking reviews and placing them at their appropriate positions. The study derived helpfulness scores enable re-ranking reviews of consumer products. The initial review dataset is constructed from publicly available reviews in Amazon.in. -
Indian catholic priests' identity, relational autonomy and attachment to god : A Narrative analysis
A thematic narrative analysis was carried to explore the 28 South Indian Roman Catholic religious priests identity, relational autonomy and attachment to God. Fourteen participants were selected from the structured priestly ministry settings newlinenamely education ministry and, another 14 participants from the semi-structured newlinepriestly ministry settings namely parish and priestly formation ministry settings. The newlinequalitative data collected through the interviews were analyzed through the narrative thematic analysis method. The thematic narrative analysis found five major themes, influence on the priestly identity, value-oriented life, purpose in life, priestly celibacy and challenges in the priestly ministry and 46 subthemes for the participants priestly identity narratives. For relational autonomy, the study found five major themes, impactful childhood, the influence of priestly formation, nterpersonal relationships, relationship with the person in authority and decision making and 42 subthemes. For attachment God, it found six major themes, God as an attachment figure, seeking and maintaining proximity to God, God as a haven of safety, God as a secure base, newlineperceiving God as stronger and wiser, and individual differences in attachment to newlineGod, and 24 sub-themes. The study results revealed strong support for the newlinecorrespondence pathway, as the majority of the participants had narratives of newlinecorrespondence between the attachment to their parents and their attachment to God. newlineIt also found evidence for the theme of compensation in three participants narratives. The qualitative comparison between the groups found that for 19 sub-themes for priestly identity, 20 sub-themes for relational autonomy and 13 sub-themes for newlineattachment to God, the priests from the structured ministry settings differed from the priests from the semi-structured ministry settings. -
Synthesis of Carbon Containing Composites for Energy and Environmental Applications
The population has grown rapidly, resulting in increased energy consumption and environmental issues. Researchers are developing new materials with unique physical and chemical properties to tackle these challenges. This has led to a focus on exploring novel approaches to synthesize micro and nanomaterials for use in the energy and environmental sectors. In this study, carbon-containing catalysts were developed as photocatalysts, electrocatalysts for water splitting reactions, and electrode materials for supercapacitor application. To evaluate the physicochemical characteristics of these materials, various characterization methods were employed, including X-ray diffraction, newlineScanning Electron Microscopy, Energy Dispersive X-ray Spectrometry, X-Ray Photoelectron Spectroscopy, High-resolution Transmission electron microscopy, Fourier Transform Infrared Spectroscopy, Differential reflectance spectroscopy, Dynamic light scattering, and Thermogravimetric analysis. The electrochemical and photocatalytic studies of the prepared materials were carried out by optimizing the different parameters. The four chapters include newlineCr2AlC MAX Phase as the catalyst used for photocatalysis, bismuth ferrite/Cr2CTx MXene, cobalt ferrite/Cr2CTx MXene composites for supercapacitor and electrocatalytic water splitting, bismuth ferrite/graphitic carbon nitride/N-doped graphene quantum dots for supercapacitor application, and Cobalt ferrite/graphitic carbon nitride/N-doped graphene quantum dots for supercapacitor and newlineelectrocatalytic water splitting application. -
Perceived emotional intelligence family environment and locus of control as predictors of well-being among adolescents
Adolescence is unparalleled in a person s life as the most important period in his/her newlinepersonality development. It is perceived that well-being is the keystone to an individual s wholesome being. In the past, well-being was discussed in the context of the absence of distress symptoms that include depression, anxiety, divergent behaviors and other disorders. In more recent times it has received a positive note where well-being is widely identified with the positive qualities, which each individual possesses to lead a healthy and happy life. Fifty percent of the mental health disorders begin during the onset of adolescence. There is a need to focus on adolescent well-being in India which has the world s largest adolescent population. Based on the related theories and studies, certain variables like perceived emotional intelligence, family environment and locus of control were selected for the study. The main aim of the study boiled down to two points, to investigate the relationship between perceived emotional intelligence, family environment, locus of control and well-being among adolescents and to research and explore the extent to which newlineperceived emotional intelligence, family environment, locus of control and the newlinedemographic variables (gender, type of family and religion) would contribute towards newlinethe development of well-being among adolescents. Accordingly psychological tools newlinewere adopted. The sample consisted of 903 students studying in plus one and plus two newline(age 16-18 years) Government aided and unaided state-syllabus schools in Parur, subdistrict of Ernakulum, Kerala. Among them 450 adolescents were from nuclear families and 453 others were from joint families. Gender-wise the sample constituted of 413 adolescents males and 490 females. A quantitative survey method design and newlinepurposive sampling method was adopted in the study. Spearman s coefficient of correlation was used to measure the relationship between the variables. -
Nanomaterial - Based Electrochemical Sensor for Monitoring Potential Biomakers of Chronic Disorders
Detecting various biomarkers in the health industry and the biomedical sector has been newlinesignificant due to their crucial role in diagnosing, assessing, exposing, and treating disorders. This work reports electrochemical sensors for detecting biomarkers using different modifications (2D materials and nanomaterials) on carbon fiber paper electrode-based (CFPE) sensors. Adopting these modifications on the CFPE electrode greatly intensified the oxidation and reduction of peak current values. The physio-chemical characterizations of the designed electrodes were examined employing Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Electron Diffraction X-ray (EDX), X-Rayv Photoelectron spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR), and Raman Spectroscopy. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) newlineassisted in optimizing the electrochemical properties via Nyquist plots, sensing performance, scan rate effect, and pH effect. Both electro-activity studies and Nyquist plots confirmed the enhancement in the electroanalytical performance of the fabricated electrodes. Real sample newlinestudies were successfully analyzed using developed electrodes, producing good recovery newlinepercentages. Overall, all the works conducted have been established to be facile and selective, with novelty in the fabrication of ultrasensitive voltammetric-based sensors to quantify different biomarkers. -
Design and Implementation of Low Complexity Multiplier-Less Reconfigurable Band Tuning Filter Structure with Sharp Sub-Bands
Digital flter banks are extensively used for communication purposes for channelization. Reconfgurable non-uniform multi-channels with sharp transition widths are necessary for channelization in digital channelizer and spectrum sensing in wireless communication networks. The aim of this research work is to design reconfgurable flter structures featuring non-uniform and sharp transition newlinewidth channels with reduced number of flter coeffcients. The four different flter structures are proposed in this research for achieving low complexity reconfgurable structure for the design of multiple non-uniform sharp transition width arbitrary bandwidth channels. The foundational newlineelement of this research is centered around the design of a prototype flter. This prototype flter serves as a basis for developing various reconfgurable flter structures. Leveraging the prototype newlineflter s bandwidth characteristics, these structures are categorized into two main groups: narrow band prototype flters and wide band prototype flters. The narrow band prototype flter category comprises structures capable of designing a single fnite impulse response flter with a narrow passband characterized by sharp transition widths. In contrast, the wide band prototype flter category includes structures capable of designing a single FIR flter with a wide passband also characterized by sharp transition widths. A novel flter structures are designed with the help of interpolated newlinefnite impulse response, cosine modulation technique, complex exponential modulation technique and frequency response masking techniques. The proposed method is evaluated using MATLAB R2019b, where the linear phase FIR flter coeffcients are computed based on the Parks-McClellan algorithm. The examples are employed to illustrate the effcient operation of the proposed designs. The results point to the fact that the proposed designs have less multiplier complexity than existing cuttingedge techniques. -
Modified carbon based electrodes for electrochemical sensing of biomolecules
Now-a-days a large variety of biological analytes are detected by highly sensitive newlineelectrochemical sensors which are inexpensive and simple as compared to conventional methods such as UV-vis absorption spectroscopy, spectrofluorometry, HPLC and gas chromatography. Electrochemical analysis is exceptional owing to its economical, low energy consuming and unique approach in the method design, and high sensitivity for the analyte determination. Carbon based electrochemical sensors are commonly used because of their low cost, good electron newlinetransfer kinetics, good chemical stability, and biocompatibility. Recently electrochemical properties of pencil graphite electrodes (PGEs) have been explored in the analysis of various organic compounds. High electrochemical reactivity, easy modification, commercial accessibility, fine rigidity, disposability and low-cost of PGE make it ideal to be used as an effective working electrode. The thesis presented explains different modified PGEs have been employed in the electrocatalytic determination biomolecules such as cholesterol, cortisol, Vitamin B6 and morin. newlineThe modified electrodes are effectively used for the ultra-level sensing of these biomolecules in real samples. The electroactive surface area and the conduvtivity of bare PGE is enhanced newlinedifferent electrode modifiers such as and#946;-CD, graphene, conducting polymer, metal oxides and metal nanoparticles. The modified electrodes are found to exhibit good electrocatalytic behavior towards the target biomolecules. Cyclic voltammetric (CV) studies and electrochemical impedance spectroscopic (EIS) technique were used to investigate the electrochemical properties of the modified sensing platform. The newlinemorphology and step wise fabrication process of the modified electrodes were characterized byvii Ramana spectroscopy, X-ray photoelectron spectroscopy (XPS),scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). -
Modified Carbon Based Electrodes for Electrochemical Sensing of Biomolecules
Now-a-days a large variety of biological analytes are detected by highly sensitive newlineelectrochemical sensors which are inexpensive and simple as compared to conventional methods such as UV-vis absorption spectroscopy, spectrofluorometry, HPLC and gas chromatography. Electrochemical analysis is exceptional owing to its economical, low energy consuming and unique approach in the method design, and high sensitivity for the analyte determination. Carbon based electrochemical sensors are commonly used because of their low cost, good electron newlinetransfer kinetics, good chemical stability, and biocompatibility. Recently electrochemical properties of pencil graphite electrodes (PGEs) have been explored in the analysis of various organic compounds. High electrochemical reactivity, easy modification, commercial accessibility, fine rigidity, disposability and low-cost of PGE make it ideal to be used as an effective working electrode. The thesis presented explains different modified PGEs have been employed in the electrocatalytic determination biomolecules such as cholesterol, cortisol, Vitamin B6 and morin. newlineThe modified electrodes are effectively used for the ultra-level sensing of these biomolecules in real samples. The electroactive surface area and the conduvtivity of bare PGE is enhanced newlinedifferent electrode modifiers such as and#946;-CD, graphene, conducting polymer, metal oxides and metal nanoparticles. The modified electrodes are found to exhibit good electrocatalytic behavior towards the target biomolecules. Cyclic voltammetric (CV) studies and electrochemical impedance spectroscopic (EIS) technique were used to investigate the electrochemical properties of the modified sensing platform. The newlinemorphology and step wise fabrication process of the modified electrodes were characterized byvii Ramana spectroscopy, X-ray photoelectron spectroscopy (XPS),scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). -
A Study on Some Eccentricity Related Problems in Graphs
The concepts related to eccentricity in graphs are explored in this research work. newlineThe eccentric graph Ge of a graph G has the same vertex set as that of G and two newlinevertices in Ge are adjacent if one is the eccentric vertex of the other. The eccentric newlinegraphs of some graph operations are explored, and the iterated eccentric graphs Gek newlineare introduced. The process of inding eccentric graphs, known as eccentrication, is newlinestudied in detail. Graphs that result in a complete graph Kn upon iterative eccentrication are characterized, and the cyclic property of eccentrication is established for various cycle-related graphs. The eccentrication of tree graphs is studied in detail, and a general result on the cyclic property of trees is obtained. A conjecture on the cyclic property of eccentrication for any graph G is made. The ei-signed graph of a graph G, where the edge between vertices u and v receives a sign and#963; = (and#8722;1)|ecc(u)and#8722;ecc(v)|, where ecc(u) is the eccentricity of vertex u, is investigated. General properties of ei-signed graphs, such as homogeneity, consistency, switching, and sign compatibility, are discussed. Properties that behave diferently across various classes of graphs are explored. Finally, the scope of this study is presented, and some open problems in the area are provided.