http://localhost:8081/jspui/handle/123456789/16 2026-05-07T21:26:42Z http://localhost:8081/jspui/handle/123456789/20714 Title: SIMULATION ASSISTED AND EXPERIMENTALLY TESTED 3D PRINTED IONIZATION RADIATION SHIELD Authors: Ratilal, Meher Abstract: This study investigates the lightweight polylactic acid (C3H4O2)n as a material for ionisation radiation shielding applications. Through a combination of Solid- Works software for shield design and Monte Carlo simulations using Geant4 for comprehensive analysis, the effectiveness of the design PLA shield after removing significant weight in the form of hollow spheres with a radius of 4mm and number of hollow spheres(72, 40, 24, 16, 8) in a cuboid shield with dimension( 5.3, 3.8, 2.4)cm in geant4. Using SolidWorks for experimental work and geant4 designed through C++ programming, the PLA shield design demonstrated that a specially designed PLA shield effectively reduces the shield’s weight. Using Geant4 allowed for a detailed examination of gamma-ray interactions with the PLA shield and plots generated in Root software, considering factors such as material composition, thickness, and geometric configuration. To count the gamma radiation, the NaI(Tl) scintillator detector was used for the Cs-137 mono-energetic source with energy 661.7 keV and activity 100kBq, a source made by the BRIT/INDIA. This study advances the ongoing efforts to develop effective and sustainable radiation shielding design solutions. It also highlights the potential of PLA as a model for determining the optimal design for gamma-ray attenuation, which can be applied to higher atomic number elements to achieve the intended outcomes. 2024-06-01T00:00:00Z http://localhost:8081/jspui/handle/123456789/20541 Title: Implementing Digital Logic Blocks using SOA-MZIs for Programmable Photonics Integrated Circuits Authors: Singh, Madhuri 2024-06-01T00:00:00Z http://localhost:8081/jspui/handle/123456789/20528 Title: Study of Hydrodynamical Behaviour and Transport Properties of Hot QCD Medium Authors: Pushpa Abstract: The primary focus of this thesis is two-fold: a) Studying the linearly stable and causal theory of relativistic third-order viscous hydrodynamics, b) A comprehensive investigation of the charge, heat, and momentum response in a hot QCD medium (called quark gluon plasma (QGP)) in the presence of a weak background constant magnetic field. A novel state of quark matter (deconfined soup of quarks and gluons) is expected to form at extremely high temperature and/or density during the ultra-relativistic heavy-ion collisions (URHICs). Under such extreme conditions, quark matter may approach local thermodynamic equilibrium, allowing the exploration of various phases as well as thermodynamic and transport properties of hot QCD medium. Determining the transport properties of this hot QCD medium formed from heavy-ion collisions (HICs) is challenging due to the lack of direct observation. Experimentally, only the energy and momenta of the particles generated in the final stages of a collision after hadronization can be observed, by which time the hot hadronic matter has cooled and become non-interacting. Therefore, to investigate the thermodynamic and transport properties of the hot QCD medium, it is necessary to model the entire heavy-ion collision process from beginning to end. The dynamic evolution of the deconfined hot QCD medium and the subsequent hot hadronic matter can be characterised using the laws of fluid dynamics, assuming that the system stays near local thermodynamic equilibrium during its evolution. Fluid dynamics, also referred to as hydrodynamics, is an effective technique for describing a system using macroscopic variables such as local energy density, pressure, temperature, and flow velocity. The earliest theoretical formulation of relativistic first- and ix x second-order dissipative hydrodynamics is well established. In the present thesis, we have formulated a linearly stable and causal theory of relativistic third-order viscous hydrodynamics from the kinetic theory in relaxation-time approximation (RTA). We have used the Chapman-Enskog-like iterative approach to solve the Boltzmann equation and obtain the dissipative correction to the distribution function. We have also demonstrated the linear stability and causality of the present formulation by considering perturbations around a global equilibrium state. 2024-09-01T00:00:00Z http://localhost:8081/jspui/handle/123456789/20525 Title: ELECTRONIC STRUCTURE, MAGNETISM AND TOPOLOGICAL PROPERTIES OF CERTAIN Eu BASED LAYERED MATERIALS Authors: Choudhury, Amarjyoti Abstract: This thesis explores the unique characteristics of the materials where electrons ex hibit unconventional behavior, particularly those with linear band dispersion near the Fermi level (FL). The quasi-particle excitations near band crossing points replicate the characteristics of relativistic Dirac or Weyl fermions and demonstrate resistance to perturbations due to the symmetry protection of topology. The intertwining of magnetism with band topology, introduces intriguing electronic band structures with topologically non-trivial properties, often leading to novel magnetic phenomena which have immense potential for applications in spintronics and quantum computing. Mag netism in condensed matter, originating from quantum mechanics, stands as a pivotal domain in both fundamental and applied physics research. The diverse behaviors exhibited by magnetic materials in response to external magnetic fields underpin es sential applications in devices like magnetic memory, spintronics, giant magnetore sistance, and beyond. In solids, the cornerstone of magnetism lies in ions harboring unpaired electrons, characterized by non-zero magnetic moments. These ions exhibit markedly distinct phenomena when they are in proximity and able to interact with each other, in contrast to their behavior when isolated or non-interacting. This un derscores the diverse range of magnetic moment interactions, specifically exchange interactions, which give rise to the myriad of magnetic properties observed in solids. 2024-06-01T00:00:00Z