Physics
https://hdl.handle.net/20.500.12818/26
Tue, 23 Apr 2024 01:06:05 GMT2024-04-23T01:06:05ZSynthesis and Thermoelectric studies of Dual ION (Ni-In, Ni-Pr, Ni-Cu, and Al-Cu) Doped ZnO Ceramics
https://hdl.handle.net/20.500.12818/1541
Synthesis and Thermoelectric studies of Dual ION (Ni-In, Ni-Pr, Ni-Cu, and Al-Cu) Doped ZnO Ceramics
C, Soumya
Fri, 23 Feb 2024 00:00:00 GMThttps://hdl.handle.net/20.500.12818/15412024-02-23T00:00:00ZQuasi particle models in quark gluon plasma under magnetic field, coulomb field and color field
https://hdl.handle.net/20.500.12818/1507
Quasi particle models in quark gluon plasma under magnetic field, coulomb field and color field
Arjun K
Quark-gluon plasma is believed to have existed in the initial moments after the Big Bang. Investigating the phase transition of hadronic matter is an essential part of studying the early universe and the behavior of matter under extreme conditions. At lower temperatures and densities, quarks and gluons exist together in a tightly bound hadronic state. However, at higher temperatures
(150–200 MeV) or at densities much greater than nuclear matter, such as those present in the early universe or in heavy-ion collisions, hadronic matter undergoes a phase transition. During this transition, hadronic matter transforms into quark-gluon plasma, where quarks and gluons are no longer confined. Developing the equation of state through various frameworks helps us understand and predict the behavior of QGP under different conditions. In thermodynamics and statistical mechanics, the equation of state (EoS) describes the relationship between various thermodynamic variables, such as pressure, temperature, and volume, for a given system. Several potential models are used to develop the EoS to describe the properties of quark matter. In the fields of high-energy
nuclear physics and astrophysics, these studies are of great significance.Our work encompasses three primary areas: (1) Deriving an equation of state for Quark-Gluon Plasma (QGP) in the presence of a magnetic field. (2) Investigating cold deconfined matter at zero Kelvin with a focus on the magnetic field’s influence. (3) Deriving and evaluating the temperature-dependent coupling constant for the φ 4 theory.We developed a modified liquid drop potential model to explore the thermo-dynamics of quark-gluon plasma (QGP) above the critical temperature, both in the absence and presence of a magnetic field. The model follows Mayer’s cluster expansion procedure. In this model, quarks and gluons are described as quasiparticles whose behavior is influenced by the QGP medium. Remarkably, even at temperatures below the critical temperature (T < T c ), the equation of state for pressure and energy density across 2, 2+1, and 3 flavors demonstrates a strong agreement with lattice data at zero magnetic field. Also, this modified
liquid drop model is in good agreement with lattice data for magnetized quark- gluon plasma in the region T > 113 MeV.In (2), building upon prior work on cold deconfined matter, we have incorporated the influence of a magnetic field. Employing standard statistical mechanics procedures, we have adapted integrals to the magnetic field environment. Analytical equations for number density, energy density, and pressure are derived. This work extends our understanding of the interplay between extreme conditions and quark matter.The final part of our thesis focuses on deriving a temperature-dependent coupling constant for the φ 4 theory. Using the imaginary time formalism in thermal field theory, we derive the running coupling constant and running mass in two loop order. In the process, we express the imaginary time formalism of Feynman diagrams as the summation of nonthermal quantum field theory (QFT) Feynman diagrams with coefficients that depend on temperature and mass. Renormalization constants for thermal φ 4 theory were derived using simple diagrammatic analysis. Our model links the nonthermal QFT and the imaginary time formalism by assuming both have the same mass scale μ and coupling constant g. When these results are combined with the renormalization group equations and applied simultaneously to thermal and nonthermal proper vertex functions, the coupling constant and running mass with implicit temperature dependence are obtained. We evaluated pressure for scalar particles in two loop orders at the zero external momentum limit by substituting the running mass result in the quasiparticle model. We successfully obtained a running coupling constant for the φ 4 theory. A noteworthy aspect of our work is the development of the “SMC” technique (Same Mass scale and Coupling), allowing the simultaneous solution of two renormalization groups of equations.
Thesis (Ph.D)- Department of Physics, University of Calicut, 2023
Sun, 01 Jan 2023 00:00:00 GMThttps://hdl.handle.net/20.500.12818/15072023-01-01T00:00:00ZStudies on gamma ray inter- action parameters of selected thermoplastic, biopolymer and rare earth oxide samples
https://hdl.handle.net/20.500.12818/1465
Studies on gamma ray inter- action parameters of selected thermoplastic, biopolymer and rare earth oxide samples
Thulasi P V
The extensive use of radiation in various fields such as medical physics, in- dustry, space research, radiation shielding, dosimetry etc. necessitates the knowledge of the parameters associated with the interaction of radiation with materials. As part of the present work, we have determined theoretically, the mass attenuation coefficient, effective atomic number and electron density of selected thermoplastic and biopolymer samples, having medical applications, for total as well as partial gamma ray interaction processes in the wide range of energies 1 keV to 100 GeV. The mass energy-absorption coefficient, the effective atomic number corresponding to gamma ray energy absorption in these media and the kerma relative to air of these polymers were also estimated for the energy range of 1 keV–20 MeV. Variation of these parameters with photon energy and chemical composition of polymers has been studied. The estimated values were compared with experimental data, wherever available, and these show good agreement. The effective atomic numbers of these polymers obtained by different methods have been compared in various energy regions and possible conclusions were drawn.
We have also estimated the radiation interaction parameters of selected chemotherapy drugs administered concurrently with radiation therapy in the energy range 1 keV to 100 GeV by using the EpiXS program. The radiation response of the selected drugs have been compared at different energy regions.Except at absorption edges, the selected drugs have shown similar interaction
parameter variations with photon energy.
We have also determined the angle integrated total scattering cross sec tions of some rare earth oxides experimentally for 59.54 keV and 662 keV gamma rays in the angular ranges of 0–4 0 , 0–6 0 , 0–8 0 and 0–10 0 . From the experimental total scattering cross sections, the corresponding angle integrated incoherent scattering cross sections obtained from ENDF library (based on the non-relativistic Hartree – Fock form factor method) was subtracted to obtain the angle integrated coherent scattering cross sections. The angle integrated coherent scattering cross sections show good agreement with that determined from ENDF data. The effective atomic numbers of the selected rare earth oxides were extracted by applying the ratio of cross section method. The variation of angle integrated coherent scattering cross section with the effective atomic number of the selected compounds have been studied.
In addition, some attenuation measurements have been carried out on edible oil samples using 662 keV gamma rays. Here, wehave determined the mass attenuation coefficients, from which the effective atomic numbers were deduced. The variation of interaction parameters with the composition of the food samples were also studied.
Thesis (Ph.D)- University of Calicut, Department of Physics, 2023
Sun, 01 Jan 2023 00:00:00 GMThttps://hdl.handle.net/20.500.12818/14652023-01-01T00:00:00ZA Study on Physical and Dosimetric Aspects of image Guided Radiation Therapy
https://hdl.handle.net/20.500.12818/1440
A Study on Physical and Dosimetric Aspects of image Guided Radiation Therapy
Silpa AjayKumar
Thesis(Ph.D)-University of Calicut,Department of Physics,2021
Fri, 01 Jan 2021 00:00:00 GMThttps://hdl.handle.net/20.500.12818/14402021-01-01T00:00:00Z