Institutional Repository

Scholar@UOC is the primary academic repository of the University of Calicut.

This repository is aimed to collect, preserve and distribute the research output of the members of our University. This is an open access system hosted and managed by the University Library.

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Recent Submissions

Facile chemical strategies for the preparation of multiwalled carbon nanotube based composite electrodes for sensing applications
(Sri Vyasa N.S.S. College, Wadakanchery, University of Calicut, 2024) Reshma, M; Manu, R
The thesis focuses on the development of different composites, based on MWCNT which finds application in various electrochemical sensing platforms. MWCNTs possess some excellent properties and this gets enhanced when metals or metal oxides are coalesced on to the CNT matrix. MWCNT composites of distinctive nature were fabricated by employing different noble metals like silver, palladium and ruthenium. Besides these metals certain metal oxides of tungsten, cobalt and iron are also incorporated. As different materials are successfully integrated, the newly formed MWCNT hybrids could possess some unique properties of all the materials that is being incorporated. More over surface functionalisation of MWCNTs provide more binding sites for the anchoring of metals and metal oxides. Further more such mild functionalisation technique can protect CNTs from structural damage also. The thesis elaborate on the fabrication of four distinct nanocomposites based on MWCNT and their usefulness in various applications. These include Ag/fMWCNT, Cu-WO3- MWCNT, Pd@MWCNT-Co3O4 and RuO2/Fe3O4/MWCNT composite electrode. Ag/fMWCNT flexible films were fabricated through facile method in which silver is being deposited on to MWCNT films by electroless deposition process. The substrate employed in this work is PET, which is flexible and the fabricated electrode can be employed for sensing dopamine. Electrochemical methods like cyclic voltammetry, differential pulse voltametry and chronoamperometry were used to study the sensing behavior of the electrode towards dopamine. The LOD values were found to be 0.7 μM. The electrode also exhibited good pseudocapacitive behavior. Another flexible film electrode Cu-WO3-MWCNT utilized the techniques viz. electroless and electrodeposition process for its formation. Tungsten oxide was incorporated on to MWCNT matrix which was then deposited on to electroless copper substrate. The preliminary and qualitative sensing of ageing of lubricant oils was studied using this electrode. This was revealed by electrochemical impedance studies. One another work reports on the development of Pd@MWCNT-Co3O4 film. The relevance of the electrode lies in the fact that cobalt oxide employed for the fabrication was recovered from spent lithium-ion battries. The cobalt was extracted from the used lithium ion batteries and then converted into oxide form and finally palladium incorporated MWCNT is being deposited on to Co3O4 film byelectrophoretic deposition process. The developed Pd@MWCNT-Co3O4 electrode was used as glucose sensor. The sensing behavior of the electrode towards glucose was revealed from the chronoamperometric studies and the limit of detection was found to be 0.6 μM. Another composite electrode based on MWCNT is from RuO2 and Fe3O4 mixed oxide. The composite was drop casted on to glassy carbon electrode and the sensing behavior of the composite towards simultaneous detection of ascorbic acid and dopamine was studied using cyclic voltammetry and differential pulse voltammetry. The limit of detection was found to be 1.12 μM for ascorbic acid and 0.11 μM for dopamine. In brief, all the nanocomposite electrodes of MWCNTs fabricated were developed through different facile strategies that were found to have good sensing capability towards different analyte molecules. The procedures adopted for the fabrication process were simple and economical. The composites films were characterized by different analytical and instrumental methods. The sensing characteristics were studied using different electrochemical techniques. All the electrodes were found to be stable and reproducible.
Studies on C Spaces
(Department of Mathematics, University of Calicut, 2024) Sruthi, A. K; Sini, P.
The concept of connectedness is discussed in numerous mathematical fields such as topology and graph theory and it is highly applicable in image filter-ing and segmentation, image compression and coding, motion analysis, pattern recognition etc. Both a topological and a graph theoretical framework are used to characterize connectivity. However, there are sometimes differences between topology and graph theory approaches to connectedness. But complications arise when these two approaches are used independently. In both theory and practice, a general description of connectedness that is applicable to both graph theory and topology is more beneficial. In 1983, R. Börger introduced an axiomatic approach to connectivity in order to standardize the definition of connectedness across these mathematical domains. The axioms were certain characteristics of connected sets such as empty set and singletons are connected and that union of connected sets having nonempty intersection is connected. A collection of sub- sets of a set satisfying these two axioms is called a c-structure and a set together with a c-structure on it is called a c-space. The objective of this thesis is to present new contributions to the theory of c- spaces. Our primary focus is on the study of order-induced c-space, which is the c-space obtained from a linearly ordered set. Here, we discuss topological order induced c-spaces. We also characterize complete linearly ordered sets and dense linearly ordered sets in relation to order-induced c-space. Then we investigate the reversible property of c-spaces. The reversible c-spaces are characterized and prove the existence of non-reversible c-spaces with any infinite cardinality. Further, we define cut-point c-spaces and investigate the features of cut-point c-spaces. Moreover, we construct a cut-point c-structure on the union of an arbitrary family of mutually disjoint c-spaces if at least one of these c-spaces is a cut-point c-space. Finally, we associate c-spaces with hypergraphs. We discuss the properties of c-structures obtained from hypergraphs. Also, we prove that its members are the vertex sets of the connected hypersubgraphs of the given hypergraph.
Atomically precise metal nanoclusters self assembly dynamics colloidal superstructures and advanced device fabrication
(Department of Nanoscience and Technology, University of Calicut, 2024) Rival Jose, V.; Shibu, E. S
Nanomaterials are fascinating because of their small size and high surfacearea-to-volume ratio, which cause them to act completely differently fromtheir bulk counterparts and display unique optical and photophysicalproperties. To fully comprehend their unique characteristics, in-depthcompositional and structural investigations are necessary. However, in thecase of metallic nanoparticles (NPs), one problem faced by researchers is thelack of monodispersity. Later, size-focused synthesis of NPs led to thediscovery of atomically precise metal nanoclusters (NCs). NCs consist of ametal core protected by organic ligands, with a core size of less than 2 nm.Since the number of metal atoms in the core and ligands is inite, they can bedenoted as [MxLy]z, where x and y represent the number of metal atoms andligands (e.g., L= thiolate (SR)), and z denotes the overall charge of the NC. NCsexhibit strong quantum con inement effects owing to their ultrasmall size,resulting in molecule-like properties such as distinct optical absorptionfeatures, photoluminescence, and enhanced catalytic activity. This makesthem valuable for diverse applications in catalysis, sensing, energy, andbiology. Recently, the self-assembly of NCs has become a “hot topic” in bothfundamental and applied research. Many nanoscale molecular interactionsat the NC surface play crucial roles in self-assembly, which can occasionallyresult in the crystallization of NCs and provide information about theirstructural and property relationships. The self-assembly of NCs intohierarchical superstructures led to enhanced photophysical properties dueto the coupling effect of neighboring NCs. One could foresee that suchenhanced photophysical properties are important for the development ofadvanced devices in the near future.This thesis is organized into seven chapters. Chapter 1 offers an overview ofNCs, covering their synthesis, isolation, properties, and applications. The second half of this chapter will discuss in detail the hierarchical self-assembly of NCs and their properties and applications. Chapter 2 discussesthe materials and experimental methods used for our investigations.Chapter 3 discusses the synthesis and photon-assisted reversible self-assembly of thiolated azobenzene-stapled Au25 NCs. Photoactivation offunctionalized NCs ([Au25C3AMT)18]−) in dichloromethane by irradiatingultraviolet light at 345 nm resulted in a visual change and formation of disc-like colloidal superstructures (d ~100-1000 nm). The superstructures arereadily disassembled into individual NCs upon irradiating with the visiblelight at 435 nm. Systematic changes in both the electronic absorption bandsand nuclear magnetic resonance spectra of chromophores in solutionsuggest that the photoisomerization of surface ligands drives the self-assembly. High-resolution transmission electron microscopy, electrontomographic reconstruction, dynamic light scattering, and small-angle X-raypowder diffraction show that the disc-like superstructures contain denselypacked NCs. Long-range self-assembly and disassembly under ultravioletand visible light, respectively, demonstrate reversible photo-switching inNCs.Chapter 4 discusses the role of chromophore-spacer length in the light-induced self-assembly. Herein, the self-assembly is studied in detail usingtwo photoswitchable NCs (C3-NC and C9-NC) fabricated using the thiolated-azobenzene molecule with different spacer lengths (C3-AMT and C9-AMT).The core and molecular information of both NCs were meticulously exploredusing various spectroscopic and microscopic techniques. Photoactivation ofboth NC solutions at ambient temperature using 345 nm light resulted in theformation of self-assembled superstructures. The C9-NCs show a fastassembly due to their improved photoswitching ef iciency resulting from thenegligible steric hindrance experienced at the NC-chromophore interface. Chapter 5 discusses the room temperature fabrication of a stable, lexible,nontoxic, and low-cost precision NC-based luminescent ink for the stencilprinting of an optically unclonable security label. NC-based printing inkshowed brilliant photoluminescence owing to its extended C− H···π/π···πinteractions. Spectroscopic and microscopic investigations show thatintercalated NC in printed security labels are highly stable as their opticalfeatures and molecular compositions are unaffected. The exceptionalmechanical, thermal, photo, and aqueous stabilities of the printed securitylabels endorsed to demonstrate the printing and smartphone-basedelectronic reading of the quick response code on a currency. Finally,con idential information protection and decryption under a precise windowof light have been achieved by adopting the optical contrast illusion. Thepolyurethane elastomeric binder helped to hold the printed QR code oncurrency even after multiple folding and wetting. The overall cost of thesecurity label is found to be approximately 0.013 USD per stamp.Chapter 6 discusses a highly stable, solid-state emitting bimetallic copper-gold nanocluster [Au2Cu6(Sadm)6(DPPEO)2], using adamantane thiol and1,2-bis(diphenylphosphino)ethane as primary and secondary ligands.During the synthesis, only one phosphine is bound to gold and the secondone has oxidized to P = O bond. The strong hydrogen bonding between P = Oand the adamantane hydrogen atom facilitated rapid crystallization. The NCilm and crystals show better photostability compared to its solution. Due totheexceptionalphotostabilityandsolid-statephotoluminescence,[Au2Cu6(Sadm)6(DPPEO)2] NC has been successfully employed to fabricatean electroluminescent light-emitting diode without additional hostmaterials. The fabricated electroluminescent light-emitting diode shows amaximum brightness of 1246 cd/m2 and an external quantum ef iciency of12.6 %.
Biomechanical analysis of selected judo techniques interpretations on kinematic variables in accordance with competition weight categories
(Department of Physical Education, University of Calicut, 2023) Rajkiran A.K; Sakeer Hussain V.P
This research study was engrossed on biomechanical analysis of judo techniques, aimsto provide a comprehensive understanding of the kinematic properties and itsinteractions involved in the execution of judo techniques with respect to thecompetition weight categories. By rigorously analysing the selected techniques usingmotion capture technology and biomechanical principles, the researcher seeks tocontribute to the development of evidence-based training methods and competitionstrategies in the field of judo. To determine the influence of weight categories onkinematic variables with respect to the execution of selected judo techniques in theAll-India Interuniversity level judo championships. The objectives were as toinvestigate the differences in kinematics among the judo techniques chosen withrespect to the weight categories in the All-India Interuniversity level judochampionships, to quantify the kinematic properties of the judo techniques chosen andto compare specified kinematical characteristics between various weight categories.To meet the objectives three research hypothesis formulated was there is a significantinteraction between Weight Categories and Judo Techniques on Kinematic Variablesin the execution of selected judo techniques at All-India Interuniversity level judochampionships. MANOVA was used as the statistical tool and the result shows thatthere is a significant interaction between competition weight categories and selectedjudo techniques with Pillai’s trace F value 19.302 which was significant since p value(0.001<0.05) at 0.05 level. Therefore, the hypothesis Between Groups were accepted.With this study the researcher contributes to the growing body of knowledge in judobiomechanics by revealing significant differences in kinematic variables acrosscompetition weight categories and selected techniques. By elucidating these nuances,we aim to facilitate informed coaching practices, refine training methodologies, andultimately elevate the performance standards within the sport of judo.
Public attitude on compliance to law in Kerala An analysis
(Department of Political Science, University of Calicut, 2024) Ajith P.G.; Zacaria T. V
The process of Political modernization in India commenced with theadoption of the constitution of India on January 26th 1950. Many successfulprinciples of governance were adopted from different countries around the world asa part of modernisation efforts. Rule of law is one of such principles of moderngovernance and subsequently many associated structures and institutions wereadopted to implement it. The adopted structures and institutions become successfulonly if they have a supporting political culture and behavior. But Unfortunately inIndia the imported new structures and institutions had to work with traditionalculture and behaviors. This incongruity led to the development of Riggs' prismatic-sala model.In this background this research aims to investigate the attitude of people ofKerala towards compliance to law. The study is intended to address questions likewhy people obey or disobey laws in Kerala society, the factors influencingcompliance with law, public attitude towards law and punishment. It was identifiedthat there are four basic factors which shape compliance to law, like personal moralvalues, social pressure, deterrence and legitimacy. In traditional societies peoplebasically obeyed laws because of personal moral values and social pressure. Withthe establishment of the state, the factor influencing public compliance to lawbecame deterrence. State makes laws and forces the people to obey those laws withcertainty, severity and harshness of punishment mechanisms. Subject-rulerdifference is very prominent in such a society. Rulers force the people to obey thelaws with the help of deterrence mechanisms.Deterrence based governance is not very effective, it needs a lot of resourcesand it's very expensive. With the establishment of modern national states withdemocracy and republicanism, the difference between the rulers and subjectsdrastically reduced. The ideal democratic republicanism visualizes a commonwealth,where everyone is a ruler and a subject. Rational legal authority became the base ofgovernance and voluntary compliance with law is accepted by all. So it is a journey from personal moral values to voluntary compliance based on the acceptance ofrational legal authority. Law enforcement will be effective only if it is based uponthe factors shaping compliance to law. Blindly adopting reforms from highlydeveloped countries without considering the local factors shaping compliance to lawwill lead to lawlessness and anarchism. Additionally, the research considers the roleof the primary law enforcement agency, the police department, as a secondaryobjective of this research. It explores the public perception of the police and viceversa. Examining why policing remains a challenge despite numerous reformatoryefforts. Furthermore, the researcher analyzes various police reforms in the light ofthe survey results on public attitude towards laws and the factors shapingcompliance to law.