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ThesisItem Open Access Synthesis and characterization of Ni-Zn doped ferrite nanoparticles(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-07) Joshi, Rita; Goel, PujaA high level of attention today is being given to Nanoscience and Technology worldwide. In the present work, all the nanoparticles are synthesized by Chemical coprecipitation method. Firstly Magnetite nanoparticles are formed which are found to be oxidized to Maghemite phase. Maghemite phase is indicated by a peak shoulder in the FTIR spectra. To tackle this problem of oxidation and agglomeration, oleic acid is used in next synthesis of Magnetite. The prepared samples were characterized by FTIR, where peak of C=O confirms that oleic acid is successfully grafted in the surface of the particles. The peak shoulder corresponding to Maghemite phase is not visible in FTIR spectra. Oleic acid is found to be a better caping agent in protecting further oxidation of Magnetite. To enhance some properties of Ferrites, Ni (Magnetic) and Zn (Non magnetic) are doped in various stochiometric ratios. Ni-Zn doped nanoparticles coated with oleic acid are again synthesized by chemical co-precipitation method. FTIR study reveals the presence of Maghemite phase. The particle size is calculated to be around 7 nm for all the samples and the lattice parameter varies from 8.21 Å to 8.32 Å. Lattice parameter for Ferrite doped with only Zinc is highest i.e. 8.32 Å while the lattice parameter of Ferrite doped with only Nickel is found to be least i.e. 8.21 Å. For intermediate doped particles, lattice parameter varied due to contradictory positions of Ni and Zn in Magnetite and Maghemite. No significant effect of Ni-Zn doping is observed in particle size. EPR study tells the Ferromagnetic nature of the Ni-Zn Ferrites. It can be concluded that oleic acid works well as a surfactant for Magnetite particles but was not able to protect Ni-Zn doped Ferrite nanoparticles or the proper amount of Oleic acid to be used in Ni-Zn Ferrite must be calculated in further studies.ThesisItem Open Access Study of structural and optical behaviour of non-stoichiometric hexagonal YMnO3(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-07) Mehra, Priya; Dixit, GaganThesisItem Open Access Differential and double differential cross sections for neutron induced reactions on Cr, Fe & Ni based on TALYS 1.9(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-07) Bhatt, Kavita; Pandey, BhawnaSustainable development requires international cooperation and the effective use of technology. The factors contributing to the continuing interest in nuclear power include increasing global demand for energy, as well as concerns about climate change, increasing fossil fuel prices and security of energy supply. There are revolutionary possibilities in the development of fusion reactors. Fusion power offers the prospect of a long-term efficient energy production. Neutron cross-section data are the backbone for the designing of the critical component of fusion reactor. Complete set of neutron cross-section data is one of the urgent requisites for the successful operation of the upcoming fusion reactor. Out of the all the neutron induced reactions, the ones that produce gases are of utmost importance. The generation of hydrogen and helium gases are mainly through (n,p) ( n, n’p), (n,_), (n, n’_) reactions. These reactions are induced on the first wall, structural and blanket components of the reactor. In addition to the production of hydrogen and helium, the other processes such as atomic displacements and transmutations, etc., can produce micro structural defects and damage physical properties of the material. The materials suitable for the reactor structures are stainless steel with Cr, Fe and Ni as the main constituents. Very less experimental data is available for DX and DDX in EXFOR nuclear data library. The main reason can be attributed to the experimental difficulties, such as background counts, detector resolution, particle discrimination, relatively small values of nuclear cross-sections, etc. The present investigation is carried out to find the differential cross-section (DX) and double differential cross-section (DDX) values of Cr, Fe and Ni for (n,xp) and (n,x_) reactions at neutron energy 14.1 and 14.6MeV using TALYS-1.9. The contributions from direct, pre-equilibrium and compound nucleus processes to the total reaction are studied along with the study of all the open reaction channels for (n,xp) and (n,x_) reaction.ThesisItem Open Access Synthesis and characterization of graphene based nickel ferrite nanocomposites(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-07) Bhatt, Himanshu; Srivastava, R.C.Nickel ferrite (NiFe2O4) is an electrically insulating material, whereas reduced graphene oxide (rGO) possesses electrical and thermal conductivity, mechanical strength and chemical stability. The inclusion of rGO with NiFe2O4 leads to formation of chemically stable and magnetic nanocomposites, which can conduct electricity. Graphene based magnetic nanocomposites are frequently used in supercapacitors, MRI and absorption removal of pollutants from water. Nickel ferrite nanoparticles were synthesized with an average crystallite size of ~23 nm by sol-gel auto combustion method and annealed at 500oC and 1000oC for 2 hours. Graphene oxide (GO) was synthesized by oxidation of graphite using modified Hummers method. Reduction of GO using hydrazine hydrate yields reduced graphene oxide. The rGO/NiFe2O4 nanocomposites were fabricated by mixing of NiFe2O4 nanoparticles and reduced graphene oxide into DI water followed by thermal drying. XRD, UV-Vis spectroscopy, FTIR, EDX and VSM techniques were used to characterize the nanosamples. Crystallite size and lattice parameter of nickel ferrite nanoparticles were found to increase with increase in annealing temperature. The addition of rGO induced a surprising reduction in the crystallite size of nickel ferrite nanoparticles from 65 nm to 49 nm with retaining spinel structure. The co-existence of both phases of rGO and NiFe2O4 nanoparticles in nanocomposites were confirmed by XRD, FTIR and elemental analysis. Band gap increased while saturation magnetization and magnetic moment per mole of NiFe2O4 decreased with decrease in crystallite size. The XRD and optical analysis validated the formation of GO and rGO. Band gap of rGO showed inverse proportionality with reduction time. Elemental analysis revealed that C/O atomic ratio increased from 0.70 to 6.98 after reduction of GO into rGO. Through VSM analysis, it was observed that the saturation magnetization is reduced, whereas coercivity increased by the addition of rGO into NiFe2O4 nanoparticles. The obtained results from present investigation suggest that the electrical and magnetic properties of rGO and NiFe2O4 can be tuned according to the desired applications.ThesisItem Open Access Study of optical properties of zinc doped tellurite glasses(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-07) Gangwar, Harshita; Singh, VirendraAmorphous oxide of Tellurium has been extensively studied from past few years to develop promising materials which can be proved useful in ongoing research of photonics worldwide. Tellurite glass are known to possess amazing properties like high refractive index, strong linear and nonlinear response, low dispersive coefficient and many others. Tellurite glasses are widely used in optoelectronic research and have been used to make fibers for the purpose of electro-optics. They have greatly enhanced the world of optics with their exceptional properties. Other than that, the physical properties possessed by tellurite glasses like hygroscopic nature, chemical durability etc. has made them a stable product. Tellurium is a conditional glass former. Addition of transition metal oxide in a stochiometry concentration is required to turn tellurium into glass. ZnO containing tellurite glass can be formed with glass forming range up to 40% ZnO. Moreover the ZnO doped tellurite glass has known to shown a wide range IR transmission. The principal purpose of this study is to develop optical glasses with refractive indices above 2.1 and to investigate some of their optical properties as a function of composition. Systematic series of ZnO-TeO2 glasses has been synthesized to study the physical and optical properties using various characterization methods like UV-VIS, FTIR, XRD, DSC etc. Optical and physical constants of these glasses have been determined over a spectral range.ThesisItem Open Access Reinvestigation of Ghoshal experiment based on Talys- 1.8 code(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-06) Sukhvinder Kaur; Agrawal, H.M.The cross-section (excitation functions) of nuclear reaction taking place in nuclear reactor plays an important role in the present era. Nuclear data represents measured (or evaluated) probabilities of various physical interactions involving the nuclei of atoms. Nuclear data encloses all quantitative results of nuclear physics and comprise the areas of nuclear reaction, nuclear structure and nuclear decay data. The present study is based on Bohr compound nucleus theory. Ghoshal experiment is reinvestigated by the using TALYS- 1.8 code. The present study is to calculate the cross-section of those reactions involving unstable target nuclei. In such cases, by using this verification of Bohr compound nucleus model the cross-section of the reaction can be predicted theoretically. These theoretical calculations have been performed with optimized input and different level density parameter using recent TALYS 1.8 code from the energy range threshold to 20 MeV. The obtained results have been compared with EXFOR data along with the experimental data available in the literature. It is concluded that computed results using TALYS 1.8 code is compatible with the experimental data from the literature.ThesisItem Open Access Role of quaternions in dyonic cold plasma(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2018-07) Pathak, Mayank; Chanyal, B.C.In this study, we have made an attempt to formulate the generalized dualmagneto hydrodynamics (MHD) of the dyonic cold plasma in terms of quaternionic formalism. Quaternion is a norm-division algebra over real, which shows four dimensional Euclidean space-time structure. The generalized dual MHD describes the motion of dyons (associated with electrons and magnetic monopoles) in cold plasma fluid. In cold plasma, we consider the temperature of dyons is very less in compared to sun. In other words, the dual MHD theory of cold plasma is an approximation theory, where we neglect the temperature effect. Starting with the quaternionic dual velocities, we have obtained an expression for generalized dyonic field of the cold plasma, namely, the hydro-electric field and the hydro-magnetic field. The hydro-electric field is analogous to the generalized Lamb vector field, while the hydro-magnetic field is analogous to the generalized vorticity vector field for dyonic fluid. The dual Lorentz gauge like conditions, respectively for the hydro-electric and hydro-magnetic field are obtained. Further, we derive a quaternionic expression to the generalized Dirac-Maxwell equations for the dyonic cold plasma which showing a well invariant nature under the duality, Lorentz and CPT transformation. We also discuss the quaternionic unified hydro-electromagnetic wave equation for the dyonic cold plasma. It should be noticed that the hydro-magnetic wave equation shows an analogous to Alfven wave equation which may be generated by magnetic monopoles. Thereafter, we obtain the generalized energy-momentum conservation laws for the hydro-electric and hydro-magnetic field of the dyonic cold plasma. We discuss the Poynting theorem or conservation of energy by comparing the scalar coefficient, while the conservation of momentum is described by comparing vector coefficient of quaternionic formulation. Therefore, these quaternionic expressions, i.e., for the generalized hydro-electromagnetic wave and for the energy-momentum conservation relations are showing an invariant nature under the duality, Lorentz and CPT transformations.ThesisItem Open Access Determination of leaf water parameters of sarpgandha (Rauwolfia serpentina L.) plant using beta gauging technique(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2013-07) Tiwari, Bhoopendra Chandra; Joshi, G.C.The present study is concerned with the determination of the physiological parameters such as fresh leaf thickness and water content (actual and relative) of a medicinal herb Sarpgandha (Rauwolfia serpentina L.) leaves. We have measured the changes in these physiological parameters as a function of height of leaves from ground level. These parameters were calculated by beta gauging method by using 204Tl and 90Sr- 90Y beta sources of energy 0.77 MeV and 2.28 MeV respectively. The results were also compared with weighing method. The observations showed that the fresh leaf thickness decreased exponentially with the height of plant leaves from ground level. However, the actual water content and relative water content increased exponentially with the distance of leaves from ground level. The actual water content and the relative water content showed the linear relationship. The mass absorption coefficient ( ) was also determined by the beta gauging method and compared with the empirical relation. The observations showed that the mass absorption coefficient depend only on the end point energy of beta particle. The study further suggests that the beta gauging method is a rapid, effective, non-destructive and powerful tool to follow the changes in physiological parameters of plant leaves.ThesisItem Open Access Size and shape dependent thermodynamic study of nanometals(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2017-07) Uniyal, Shalini; Joshi, Deepika P.Thermodynamics of nanometals has became a great area of research due to their wide range of applications in many field of science. In the present work four different models i.e. Qi’s model, Qi-Wang’s model, Jiang’s model and Lu’s model have been used to study size and shape dependent melting temperature, Debye temperature and specific heat of Nanometals. These thermodynamic properties are calculated for different sizes and shapes like spherical, regular tetrahedral, regular hexahedral and regular octahedral. Sn, Pb, Bi, In, Cd, Al, Au, and Ag nanometals are taken for the study of size and shape dependent melting temperature, the size and shape dependent study of Debye temperature is done for Au, Fe, Sn and Co nanometals. Ag and Au nanometals are used for the study of specific heat. The calculated results obtained from these models are compared graphically with available experimental and simulated data.For melting temperature, the results obtained from the equation given by Qi-Wang’s model (for D<15nm) and Qi’s model ( for D>15nm) are found closest to available experimental and simulated data. Jiang’s model is found to be most suitable for the study of Debye temperature of nanometals. For the study of size and shape dependent specific heat, modified specific heat relation of Qi’s model gives better result. Present study reveals that the thermodynamic properties of nanometals are not only size dependent but also varies with shape for small sized nanoparticles. The shape of nanometals for particular size can also be predicted with the help of this study. The shape factor is found to be more pronounced at lower sizes while its effect becomes negligible for higher sizes.