Department of Physics
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Item Study Of Potentials In Dense Plasma's(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2019) Arroj Ahmad Khan; CIIT/FA13-PPHY-002/LHR; Dr. Muhammad Jamil Assistant Profesor; LHR TP 5803The study of potentials in dense plasmas focuses on the effective interaction between charged particles under conditions of high density and strong coupling. In such plasmas, classical Coulomb interactions are significantly modified by screening, particle correlations, and quantum effects such as diffraction and degeneracy. These modified potentials play a crucial role in determining thermodynamic properties, transport coefficients, wave dispersion, and collective behavior of dense plasma systems. Accurate modeling of interaction potentials is essential for understanding plasma behavior in environments such as inertial confinement fusion, warm dense matter, and astrophysical plasmas.Item Collective Interactions In Dense Plasma's(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2018) Areeb Fatima; CIIT/FA13-PPHY-001/LHR; Dr. Muhammad Jamil; LHR TP 5802Collective interactions in dense plasmas arise from strong coupling between charged particles, where long-range electromagnetic forces dominate individual particle behavior. These interactions lead to collective phenomena such as plasma oscillations, screening effects, wave propagation, instabilities, and transport processes that differ significantly from those in weakly coupled plasmas. In dense plasma environments—such as inertial confinement fusion, astrophysical objects, and solid-density laser–matter interactions—quantum effects and correlation among particles further influence collective dynamics. Understanding these interactions is essential for accurately describing plasma behavior under extreme conditions and for advancing applications in fusion energy, high-energy-density physics, and astrophysics.Item Synthesis and Characterization of Divalent and Trivalent Ions Substituted W-type Hexagonal Ferrites for High Frequency Applications(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2018) Atiq ur Rehman; CIIT/FA13-PPHY-004/LHR; Dr. Mukhtar Ahmad LHR TP 6348In recent times, there came a huge surge of interest in the field of magnetism, and research in this field has not been that much livelier than it is today. This renewed interest came mainly from three major advancements; firstly, development of completely new class of magnetic materials known as ferrites, secondly, the concept of neutron diffraction to visualize the magnetic moment of individual atoms and lastly, the evolution of computer where magnetic devices found a lot of significance [1]. Magnetic materials are usually categorized on the basis of atomic structure of the respective materials along with magnitude and sign of susceptibility as shown in FigureItem Development and Electrochemical Characterization of Nanocomposites for Biogas Based Fuel Cells(2018) Asia Rafique; CIIT/FA13-PPHY-003/LHR; Dr. Rizwan Raza; LHR TP LHR TP 5602There is an urgent need to explore affordable and renewable energy resources because of the decline in reserves of fossil fuels. Biomass is an abundantly available resource in nature and can be used to generate energy in a sustainable manner. Fuel cells deliver a combination of advantages and make use of renewable energy sources. Solid oxide fuel cells (SOFCs), specifically, overcome the petroleum scarcity issue by using biofuel. The aim of this thesis is the development of nanocomposite electrolytes and anode composite catalysts for low-temperature SOFCs fuelled with biogas for clean energy applications. In the present work, Sr/Sm-doped ceria (Sr-SDC) nanocomposite electrolytes with a core shell structure are synthesized with different compositions for low temperature SOFCs. A co-doping technique is successfully used to achieve a significant enhancement in the ionic conductivity of 0.50 S/cm at 600 ˚C for the nanocomposite electrolyte Sr0.1Sm0.1Ce0.8O2-δ-carbonate. The carbonate phase (shell layer) acts as a barrier and protects the SDC (core) from the partial reduction by the fuel. This carbonate shell introduces an interface between these two phases, which is the key to realizing the interfacial super-ionic conduction pathways. This work also describes the development of ceria electrolytes that are doped and co-doped with lanthanum (La) and zirconium (Zr) and show excellent thermal stability. The ionic conductivity of La0.2Ce0.8O2-δ (LDC), Zr0.2Ce0.8O2-δ (ZDC) and Zr0.2La0.2Ce0.6O2-δ (ZLDC) has been measured in the temperature ranges of 450 °C to 650 °C and LDC achieved a high ionic conductivity of 0.81 × 10-2 S/cm. Thermal expansion coefficients (TECs) of these electrolytes have also been found to have good concurrence and compatibility with commonly used electrolytes and electrodes. The main objective of this work is the development of stable and active anode catalysts that run over biogas as well as hydrogen for low temperature SOFCs. The anode composite Ni0.6Zn0.4- Gd0.2Ce0.8O2-δ (NiZn-GDC) has been developed that exhibits semiconductor conductive behaviour, and a maximum conductivity of 1.37 S/cm has been achieved at 600 ˚C. This composite anode is found to have excellent thermally stability as well as being carbon resistant to coking during testing with biogas. A maximum power density of xii 820 and 548 mW/cm2 has been reported with hydrogen and biogas fuels, respectively, at 600 ˚C. This thesis also describes Ni-based and Ni-free anode catalysts NiLiCu-oxide with LDC for SOFCs fuelled with biogas. The anode composite NLC622-LDC has reported a maximum DC conductivity of 3.47 S/cm with Pmax of 650 and 390 mW/cm2 for hydrogen and biogas, respectively, at 600 ˚C. A Ni free anode catalyst Zn0.2Li0.2Cu0.6O2-δ (ZnLiCu-oxide) is also developed as a potential candidate for biogas-based SOFCs that bypasses the difficulty of carbon deposition and has a maximum conductivity of 4.0 S/cm at 600 ˚C. An open circuit voltage (OCV) of 0.96 V is achieved with maximum power density of 600 mW/cm2 with biogas (50% methane) at 650 ˚C. In the present work, a theoretical model of FC system has been designed using MATLAB software, and it makes use of biomass (animal waste, redwood, rice husk and sugar cane). In the last part of the thesis, a partial research work has been conducted to cast the tapes of NiO-GDC (NiO-Gd0.1Ce0.9O1.95) as anode and GDC (Gd0.1Ce0.9O1.95) as electrolyte via aqueous tape casting method. The aqueous tape casting is an emerging and cost-effective technique for the commercialization of SOFCs but faces challenges with ceria tapes due to its poor mechanical strength and co-sintering of half-cells.