Department of Physics
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Item Formation Of Shock Like Structures In Rotating(Publisher COMSATS University Islambad Lahore Campus, 2020) Anas Ahmad,; FA18-RPH-003; Dr. Zahida Ehsan, Assistant Profesor [Supervisor]; LHR TP 6357Formation of Shock like Structures in Rotating and Viscous Pair Ion Plasma In this thesis we discuss non-linear effects in multi-component plasmas. Different types of solitary waves and soliton, are the main focus in this work. First of all we consider magneto sonic soliton propagating in external magnetic field in Electron-Positron-Ion plasma, using the effective one fluid MHD model. Two modes for the waves are discussed in the linear approximation by using the reductive perturbation scheme for these modes in the nonlinear regime. It is observed that for both the modes the angle, positron concentration, ion temperature, affect the propagation properties of solitary waves and are from those of the simple Electron-Ion plasmas. IAW is a low frequency electrostatic wave, which is supported by the ion inertia in plasma physics. Due to the compressions and rarefaction of ion number density these low frequency waves propagate in plasma. In the third chapter we investigate the linear and nonlinear properties of the IAW. The Zakharov-Kuznetsov equation is derived by employing again the reductive perturbation technique for this wave in the small amplitude nonlinear regime. This equation admits solitary wave solution. The amplitude and width of this solitary wave have been discussed with effects of obliqueness, relativity, ion temperature, positron concentration, magnetic field and rotation of the plasma. The distribution function decreases generally as a power law of the velocity instead of an exponential decrease associated with a Maxwellian distribution. A useful distribution to model plasma containing super thermal and super thermal particles is the generalized Lorentzian, or kappa, distribution function. The effect of particle trapping on the linear and nonlinear evolution of an ion acoustic wave in electron-ion plasmas has been discussed. The generalized KdV equations with associated solitary wave solutions for different ranges of parameter are derived by employing a perturbation technique. Dust acoustic wave on a very slow time scale of dust dynamics emerges as a result of the balance between dust grain inertia and plasma pressure. In chapter 4,The reductive perturbation method is used to drive Zakharov-Kuznetsov equation in relativistic, rotating, and magnetized electron-positron-ion non linear plasma. ZK equation acknowledge the solution of solitary wave.Item Fabrication Of Body Equivalent Tissue Phantom For The Evaluation Of Breast Cancer By Radiation Therapy(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2021) ABDUL MUGHNI; CUI/FA18-RPH-048/LHR; LHR TP 7245; Dr. Naima AminPreparing a phantom is a highly specialized testing object utilized in medical physics for dosimetry and evaluation of the effect of the dose distribution on cancer cells. The phantom is the best cancer investigational tool for the Medical Physicist. We will be preparing these phantoms to use as our training model. The phantom will be prepared like a real part of the human body tissues. The body or particular organ tissue-equivalent phantom was designed to minimize uncertainties in dosage measurements and treatment plan and also find the track followed by the high energy photon beam. After the preparation of our phantom, we investigate the center and surface doses by the radio-chromic film, it will be helpful in future research. The gel phantom will be irritated with the help of a photon beam and an electron beam of different energies. In this research, we will explore the diffusion of radiation in the irradiated part of the phantom and its effect on normal healthy cells of the phantom. These radiations aim to destroy a cancer cell's DNA. These radiation treatments usually include risks for adjacent healthy tissues within a f ew millimeters. Estimating ionizing radiation is important before cancer therapy. Breast cancer is reinduced by inappropriate radiation usage. Estimation of the radiation dosage may be made more precise for future treatment of any malignancy when the patient is repeatedly irradiated. The main difficulty in radiation treatment is providing a specified dosage to normal tissues. A severe lesion in healthy tissues may impede genome replication and transcription an d, if not corrected, lead to mutations that endanger the survival of cells or organs. Another aspect of this project is to revise the estimation and study of the dose calculation for further cancer treatment to keep safe the human body cellsItem Significance of Noise Reduction in Magnetic Resonance Imaging for Precise Diagnosis of Normal and Abnormal Tissues(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2020) Muhammad Awais Sardar; FA18-RPH-037; Dr. Naima Amin; LHR TP 6361Over the past few decades with the invention and use of different medical imaging techniques like CT, MRI, Digital X-Ray and Angiography, its importance has already been proven by the ability of these techniques to diagnose and treat diseases. Medical images are usually low in quality, especially when it comes to image contrastItem Redox catalyst activity study of lanthanum cerate nickel oxide in methane atmosphere for fuel cells(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2020) Waqas Ahmed; CIIT/FA18-RPH-052/LHR; LHR TP 7962Everything in the modern world runs on energy. Jobs that were once done by hand have been shifted to machines and robots in recent years. More energy is required for the proper operation of this equipment. Due to rapid population increase, poor future planning, and reliance on conventional energy supplies with inadequate infrastructure, the entire globe, particularly developing countries such as Pakistan, is experiencing a catastrophic energy crisis. Almost all mechanical tasks necessitate the use of energy. It is a crucial aspect of nature's interaction with humans. Pakistan is thought of as among the developing nations in the globe. There is a major energy deficit right now as a consequence of population increase and fundamental human needs. Over 70% of the people in Pakistan are either directly or indirectly tied to the rural sector, making it a predominantly rural nation. There are two types of energy sourcesItem Effect of Silver Species on Luminescence of Lanthanide Ions incorporated with an Amorphous host material(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2020) Muhammad Yasir Ilyas; CIIT/FA18-RPH-038/LHR; Dr. Junaid Amjad; LHR TP 6344We studied the photonic characteristics of rare earth (RE) lanthanide samarium ions Sm3+ mixed with boro-phosphate glass. We prepared samples having composition69.9% [P2O5]—5% [B2O3]—25% [Na2O3]—0.1% [Sm2O3] by varying amount of AgCl. These Sm3+ mixed phosphate glasses was prepared by highly recommended melt-quenching method. Their physical, conductive,structural,chemical and photonic characteristics are recorded. The effect of Sm3+ doping on emission spectra (up-conversion or down-conversion) and lifetimes (over all behavior) was investigated .Samples were polished, passed through finishing process and crushed into powder for characterization i.e. UV visible, XRD, Raman spectroscopy photoluminescence spectrum PL & FTIR spectroscopy. The optical band gap energy (Eopt) direct and indirect allowed transitions. Density was measured by Archimedes method, which directly correlated SPR and LSPR. The irregular shapes of atoms of the glass samples were recorded from the X-ray diffraction pattern. The emission spectrum and other optical properties were recorded using photoluminescence characterization. The fluorescence spectra of Sm3+ ions exhibit emission transition of 4G5/2→6H13/2, &4G5/2→6H5/2 under514 nm excitation wavelengths by giving emission of green and red lights. When material is excited with 514nm light source it gives rise to down conversion from green light (514nm) to yellowish green (~530nm)&red light (~650nm).Down conversion of Green visible into both yellowish green &Red visible radiation could use in no of sundry applications in such as solid state lasers, LED/LCD displays, optical fibers, and fast optoelectronic devices The electronic/conducting properties of material were studied and calculated band gap using UV visible technique.Item Synthesis of Magnesium Ferrite (MgCexFe2 xO4)/Banana Peel Composite for De-Fluoridation of Real Water Body(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2020) Naila Riaz Goraya; CIIT/FA18-RPH-004/LHR; Dr. Mukhtar Ahmad; LHR TP 6077In this study, a composite of cerium doped magnesium ferrite (MgCexFe2-xO4 , x= 0.1) and banana peel powder was prepared by hydrothermal method. The aim was to assess its suitability for removing fluoride from fluoride-contaminated water. Crystal structure and phase identification, chemical bonding, and magnetic properties were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) and vibrating sample magnetometery (VSM), respectively. XRD results reveal that the prepared ferrite exhibits single phase face centered cubic (fcc) structure having no impurity in the sample. Addition of banana peel powder has no effect on the crystal structure. The values of structural parameters greatly match with the earlier reported values for the same structure. FTIR results clearly indicate that the prepared ferrite is spinel and have well defined vibrational and stretching peaks due to different molecules present in the compound. Coercivity values for both ferrite and composite materials are found to be a few hundred oersteds which confirm the soft magnetic nature of this ferrite. The observed parameters show that the prepared composite may find applications in different fields including de-fluoridation of water. The task of de fluoridation of water will be accomplished immediately after resumption of labs which has been interrupted by corona pandemic. For this purpose, the prepared material is to be applied on real water body to assess the effects of pH, contact time, adsorbent dose and initial fluoride concentration in water.Item Strontium Doped TiO2 Nanostructures Prepared by Hydrothermal Method for Energy Conversion Applications(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2020) Faiza Naqvi; CIIT/FA18-RPH-023/LHR; Dr Saif Ur Rehman; LHR TP 6084Solar cells which are based on thin films have received great interest as an alternative to standard solar cells. They are potentially being cost-effective and efficient, with the nano scale controllability in their size, structure, and association. Nowadays, the world is facing an extreme reduction in the non-renewable energy sources. To overcome this issue, Dye Sensitized Solar Cells (DSSCs) are considered as perfect energy sources. In this research, photo-anodes of the DSSCs were synthesized using nanostructures of un-doped titanium dioxide (TiO2) and strontium (Sr) doped TiO2 with 0.05 M concentration of Sr. These nanostructures were synthesized by the hydrothermal method. The thin films of these nanostructures were deposited on electrically conductive Fluorine-doped tin oxide (FTO) coated glass by doctor-blade method. After the preparation of photo-anodes, various analysis were performed using different characterization tools e.g., UV-Vis analysis, Electrochemical Impedance Spectroscopy (EIS) and Scanning Electron Microscope (SEM) to examine the various properties of material such as optical, electrical, and morphological properties. SEM results showed the surface morphology of prepared nanostructures and average particle size is 80-100 nm. UV-Vis analysis revealed the absorption spectra of both doped and undoped TiO2. Tauc plot was used to calculate the band gap value of undoped TiO2 that was 3.0 eV. Similarly, the band gap value of 0.05M Sr doped TiO2 was observed 2.90 eV. At the end cells were fabricated, to study its photovoltaic properties through simulation (J-V measurements). The results of this research showed that 0.05 M Sr doped TiO2 has efficiency (2.25%) and for undoped TiO2 nanostructures efficiency is (1.99%). ixItem Preparation and Investigate Electrochemical Properties of Co-doped Strontium Iron Titanium (SFT) for solid oxide fuel cell.(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2020) Irfan Ullah; CIIT/FA18-RPH-042/LHR; Dr. Muhammad Ajmal Khan; LHR TP 6363The synthesis of barium chloride and lanthanum nitrate doping with SFT based composite material as an effective cathode material in solid oxide fuel cell. As fuel cell is an efficient device for its clean energy production. To enhance the efficiency of such type of clean energy devices an efficient electrode material is required for its proper working. In fuel cell, there is also a need to study the behavior of liquid fuel as well as their performance by using proper electrode material and catalyst. For this purpose to synthesize cathode material at nanoscale for SOFC to have high electrical conductivity and power density at low temperature. This approach is to prepare nanomaterial of the cathode for SOFCs that are low cost and operate efficiently at low temperature. A series of three samples of BaSrFeTi (BSFT) and three samples of LaSrFeTi (LSFT) nanomaterials for cathode has been fabricated and investigated. The variety of nanocompsite cathode materials were synthesized with different compositions by the Sol-Gel method, and sintered at 800 0C for four hours, and then grinded. These samples were characterized by XRD, EDX, SEM, and DC conductivity measurement. The prepared samples also shows at low temperature better electrical conductivities of BSFT is 0.13 Scm-1 at 650 0C and LSFT is 0.10 Scm-1 at 650 0C. The XRD results that both material Ba0.1 Sr0.1 Fe0.2 Ti0.6 (BSFT) and La0.1 Sr0.1 Fe0.2 Ti0.6 (LSFT) has a crystalline structure with three-phase(hexagonal, monoclinic, monoclinic), and their average crystalline size is 26.0 nm and BSFT has crystalline structure with tow-phase(hexagonal, monoclinic) their average crystalline size is 38.0 nm. The SEM results of samples represent that materials are homogenous and porous. The EDX analysis of samples successfully show their elemental composition and conformity.Item Simulation and Synthesis of Aluminum (Al) Substituted Hematite Nanomaterials(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2020) Qaiser Ali; CIIT/FA18-RPH-040/LHR; Prof. Dr. M. Asif; LHR TP 6362The recent momentum in energy science has streamlined the photoelectrochemical (PEC) cell conversion of solar to electrical energy. There are various advantages to these PEC cells, such as low-cost thin film processing, a decrease in the loss of absorption (due to translucent electrolytes), and a significant improvement in the efficiency of energy transfer. As a photoanode for water-splitting purposes, alpha-hematite has gained significant attention in modules for photoelectrochemicals (PEC). The nanomaterial alpha-hematite (-Fe2O3) is appealing since to the 2.1eV bandgap, which allows it to absorb visible light. Low cost, chemical stability and abundance in nature, and outstanding photoelectrochemical advantages of -Fe2O3 include (PEC) properties for dividing hydrogen and oxygen into water. -Fe2O3, however suffers from low conductivity, sluggish surface kinetics, and low diffusion of the carrier that causes PEC system output degradation. Higher resistivity, sluggish surface kinetics, poor electron mobility, and higher electro-hole combinations are related to the low carrier diffusion of -hematite. Doping, which shapes the nanocomposite and nanostructure films, can improve all the inconveniences of -Fe2O3, such as low carrier mobility and electronic diffusion properties. In this project, using the hydrothermal method, all nanomaterials were synthesized and analyzed using Scanning Electron Microscopy (SEM), X-ray Diffractometer (XRD) and density functional theory (DFT), respectively. The morphology of the surface is analyzed by SEM. To define the crystalline phase and approximate the crystalline size, the X-Ray diffractometer (XRD) is used. Density-functional theory (DFT) is a tool of computational quantum mechanical modeling used to investigate the electronic structure (or nuclear structure) of many-body structures, especially atoms, molecules, and condensed phases (primarily the ground state). By aluminum (Al) doping or composite forming containing -Fe2O3, the mobility and carrier diffusion properties of -hematite (-Fe2O3) can be changed. By strain integration into the lattice structure, the new composite, Al- -Fe2O3, strengthened the charging transport properties, thus increasing light absorption. Clustering is seen by the rise in Al content in -Fe2O3 due to the denser formation of the ix Al--Fe2O3 particle. The presence of aluminum allows the structural, optical and morphological properties of Al--Fe2O3 to alter rather than the photocatalyst properties of -Fe2O3. The bandgap from 2.1 to 2.4 eV has a marked difference. A rhombohedra structure is seen by the structure of the composite formation Al- -Fe2O3, owing to a high percentage of Al. The increased hydrogen production of the Al- -Fe2O3 based photocatalyst is clearly differentiated by the photocurrent (35 A/cm2 ). The composition and morphology of the magnetic properties of the synthesized samples is related. We infer that shape anisotropy mediated enhancement of coercivity in hematite nanoplates, while hematite ellipsoid 3D superstructure (nanoparticle clusters) induced multidomain magnetic structure creation and maximal coercivity, revealing its superior structure for enhanced magnetic properties. The synthesized hematite nanoparticle structures have low levels of cytotoxicity on the cell line of human lung fibroblasts (MRC5), indicating a healthy use for practical applications of these nanoparticles.Item Plasmonic interactions of silver nanoparticles with quantum dots embedded in borophosphate amorphous matrix: A photoluminescence study(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2020) Muhammad Zeshan Haider; CIIT/FA18-RPH-013/LHR; Dr. Junaid Amjad; LHR TP 6358We studied the photonic characteristics of Cadmium sulfide (CdS) with boro-phosphate glass. We prepared samples having composition 5% [P2O5]—70% [B2O3]—25% [Na2O2] 1% [CdS] by varying amount of AgCl. We mixed CdS with phosphate to prepare glasses by highly recommended melt-quenching method. Their physical, conductive, structural, chemical and photonic characteristics are recorded. The effect of CdS doping on emission spectra (up-conversion or down-conversion) and lifetimes (over all behavior) was investigated. Samples were polished, passed through finishing process and crushed into powder for characterization i.e., UV visible, XRD, Raman spectroscopy photoluminescence spectrum PL& FTIR spectroscopy. The optical band gap energy direct and indirect allowed transitions. Density was measured by Archimedes method, which directly correlated SPR and LSPR. The irregular shapes of atoms of the glass samples were recorded from the X-ray diffraction pattern. The emission spectrum and other optical properties were recorded using photoluminescence characterization. The fluorescence spectra of CdS exhibit emission transition of excitation wavelengths by giving emission of green and red lights. When material is excited with 514nm light source it gives rise to down conversion from green light (514nm) to yellowish green (~530nm) &red light (~650nm). Down conversion of Green visible into both yellowish green &Red visible radiation could use in no of sundry applications in such as solid-state lasers, LED/LCD displays, optical fibers, and fast
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