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ThesisItem Open Access Dielectric study of nematic (4-Cyano- 4’-Pentylbiphenyl) liquid crystal(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-08) Ramnivas; Goel, PujaDielectric studies of the liquid crystals are important as they provide useful information about molecular structure, molecular dynamics, phase transition and display performance of liquid crystals. Present thesis work deals with the investigation of dielectric parameters of nematic (4-cyano-4’-pentylbiphenyl) liquid crystal over a wide range of frequency (100Hz- 10MHz) at different temperatures ranging from -100C to 500C. The fabrication of liquid crystal cell was done by using the photolithography technique. For the measurement of dielectric properties parallel plate capacitor cell was used. The area and separation between the plates were taken 35.54mm2 and 14.3μm respectively. The resistance of electrode wires was very low and was soldered with the help of USS 9200 ultrasonic soldering unit. All the dielectric measurements were performed using an HP 4192A impedance analyzer. The cells with the material under the study were placed with in a Linkam hot stage (THMS 600) controlled by a Linkam temperature for insuring the desired temperature for the measurements. As a result, at low frequency, the magnitude of dielectric permittivity was found to be increased with an increase in the temperature but at the higher frequency, it was decreased. At low frequency region, the magnitude of dielectric loss increases with increase in the temperature, after attaining maxima it is decreases. It was also observed that the transition temperature from nematic to isotropic phase was 320C.ThesisItem Open Access A preliminary study on the effect of Copper nanoparticles on certain pesticides(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-07) Ashneet Kaur; Goel, PujaNanoparticles are gaining a lot of attention worldwide owing to their unique physical and chemical properties, high surface area and nanoscale size etc. Present thesis work deals with the synthesis and application of Cu NP’s. In order to obtain stable, controlled size and size distribution, Cu NPs were synthesized via chemical reduction method by controlling various reaction parameters. The synthesized nanoparticles were used to prepare stable suspension of nanoparticles. Further, suspensions of NPs were also prepared using as procured Cu NP’s by optimizing the amount of different solvents viz. acetonitrile, isopropanol, kerosene and transformer oil and surfactant i.e. oleic acid. The prepared nanosuspension were characterized using UV-VIS and FTIR spectroscopy which confirmed the formation of stable Cu nanosuspension. It turned out that Oleic acid, used in specific amounts, can act as an excellent surfactant for Cu NPs however, it was not sufficient to prevent the oxidation of NPs. To study the application of Cu NP’s in pesticide degradation, solution of different concentrations of chlorpyrifos, dichlorvos and endosulfan were prepared. The prepared pesticide solutions were added to specific amounts of Cu nanosuspension and monitored with time. Change in colour was observed for all the samples giving a colorimetric method to study the effects of NP’s on pesticides. The reaction products of pesticides were characterized using UV-VIS and FTIR spectroscopy. The UV-VIS plasmon of nanosuspension showed red shift while the absorbance band of pesticides disappeared after reaction. The FTIR spectra confirmed the degradation of organic bonds of the pesticides. The pesticides have been successfully degraded by Cu NP’s as a result of their adsorption on NP’s surface and interaction between them.ThesisItem Open Access Excitation function of 55, 56 Fe (n,p) and 59,60 Ni (n,p) for surrogate technique(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-08) Joshi, Himanshu; Pandey, BhawnaFusion contains enormous amount of energy. ITER is the first thermonuclear reactor. In the critical components of the reactor, modified stainless steel is used, which have the composition of Iron, Nickel, Chromium, Molybdenum and others in order to enhance the properties of the steel. The fast neutrons of 14MeV emitted from the fusion reactor open various neutron induced channels. But inside the reactor various unstable radionuclides are produced through several inventories which have very short half life.. Cross section of any nuclear reaction gives the probability of that reaction. The study of 55,56Fe(n,p) and 59,60 Ni(n,p) cross sections of these radionuclides formed is useful for fusion reactor interest. Due to unavailability of the target nucleus, direct calculation of cross sections of these nuclei is difficult. So we use indirect Surrogate method to measure the cross section of these nuclides. For surrogate of any reaction to be possible, the reaction should proceed through compound nuclear reaction mechanism. The Excitation Function of any nuclear reaction shows the graph between cross section of the reaction and energy of incident projectile. For reaction to proceed largely through compound nuclear reaction mechanism, the contribution of compound nuclear reaction mechanism should be maximum in total cross section of the reactions. The excitation functions of the reaction 55,56 Fe(n,p) and 59,60 Ni(n,p) are plotted using TALYS 1.9 using the keyword “components” in the TALYS to verify the maximum contribution of compound reaction mechanism. Surrogate reactions for 55,56Fe(n,p) and 59,60 Ni(n,p) are formulated and the calculation of reaction rate is also done for the optimization of the input parameters of the surrogate reactions.ThesisItem Open Access Study of optical and physical properties of Erbium (Er3+) doped Zinc Boro-Tellurite glasses(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-08) Yadav, Basant Kumar; Singh, VirendraIn present investigation, optical and physical properties of Erbium doped Zinc Boro-tellurite glasses were studied. This particular glass matrix can be used in telecommunication devices, laser fiber, EDFA and photonics application. Erbium doped Zinc Boro-tellurite glass system (EZBT) have been prepared by conventional melt quenching technique with molar composition of (55-x)TeO2- 20ZnO- 25B2O3-xEr2O3 (x = 0, 0.5, 1, 1.5 and 2 mol%). The physical, structural and optical properties are studied by analyzing the data obtained from characterization techniques i.e. Standard displacement technique, X-ray diffraction (XRD), Fourier transform infrared (FTIR) and UV-Vis spectroscopy. The obtained physical parameters like density and molar volume are found to vary linearly with increasing Er2O3 content. The amorphous nature of glass samples was confirmed by the XRD technique. FTIR spectroscopy revealed the presence of BO3, TeO4, BO4 and TeO3 stretching and vibration groups in glass samples. The optical absorption spectra of Er3+ ions in these glasses were recorded by UV-Vis spectroscopy. It was found that the optical band gap decreases and Urbach energy increases with the increase of Er3+ ion content. The refractive index, polarizability, metallization criterion, dielectric constant and susceptibility of these glass samples were also calculated. Judd-Ofelt parameters (Ω2, Ω4, Ω6) were derived with the help of optical absorption spectra. These parameters are used to calculate radiative transition probabilities, life time and branching ratio for Erbium energy level. Our detailed and systematic study provides useful information towards the applications using Er3+ doped Zinc Boro-tellurite glasses in different telecommunication devices.ThesisItem Open Access Adsorption study of heavy metals from aqueous solutions using magnetite nanoparticles(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-08) Anamika; Singh, VirendraContamination of heavy metals in wastewater is a significant worldwide problem, which causes detrimental effect on human health and environment. In present work, magnetite nanoparticles were used for the removal of Pb(II) and Cd(II) ions from aqueous solutions at varying pH conditions, contact time and adsorbent amounts. Magnetite nanoparticles were synthesized by co-precipitation method. Synthesized nanoparticles were characterized by XRD, FTIR, UV-Vis, VSM and SEM techniques for structural, optical, magnetic and morphological properties. The crystalline nature of magnetite nanoparticles with crystallite size 10.16 nm was confirmed by XRD. Optical properties and functional group identification of magnetite nanoparticles were revealed by UV-Vis and FTIR spectroscopy respectively. VSM measurements showed that the saturation magnetization of magnetite nanoparticles was 56.42 emu/g. This indicates that after adsorption, an easy separation of metal loaded magnetite nanoparticles from aqueous solutions can be achieved by applying the external magnetic field. Adsorption experiments results showed that the adsorption capacity of magnetite nanoparticles is higher for Pb(II) ions. At optimum conditions, the maximum removal efficiencies for Pb(II) and Cd(II) ions were 98.6% and 93% respectively. Langmuir and Freundlich adsorption isotherms were found applicable for adsorption processes. The adsorption kinetic data for both the metal ions were best fitted by pseudo second order reaction. Surface images of bare and metal loaded magnetite nanoparticles supported the confirmation of adsorption of metal ions on nanoparticles surface. Thus, it is concluded that magnetite nanoparticles can be effectively used as an adsorbent for expulsion of heavy metals from aqueous solutions.ThesisItem Open Access Quaternionic dirac equation in a rotating frame of reference(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-08) Sandhya; Chanyal, B.C.The Dirac relativistic wave equation combines the special relativity with quantum mechanics that overcomes the difficulties arising in Klein-Gordon equation. In present study, to construct the generalized Dirac equation for rotating particles in four-dimensional Euclidean space-time, we used the quaternionic algebra. Quaternionic algebra is generally an extension of two-dimensional complex numbers. The unitary group SU(2) which is related to the quaternionic rotation group, is isomorphic to the orthogonal group SO(3). The quaternionic moment of inertia and rotational energymomentum quaternion have been discussed by using four-vector representation of relativistic mass, space-time and energy-momentum in quaternionic form. Further, the quaternionic rotational Dirac matrices are introduced with the help of SU(2) group representation, and also derived the quaternionic form of rotational Dirac equation. A novel approach to quaternionic rotational Dirac equation contains rotational energy corresponding to the coefficient of scalar unit element (e0) and the rotational momentum corresponding to the coefficient of vector unit elements (ej). The rotational energy and rotational momentum solutions are obtained by using one, two and four component forms of quaternionic wave function. We have obtained the rotational energy solutions for positive and negative energy of particles with spin up and spin down states. The quaternionic form of positive energy relates with the existence of particle and negative energy relates with the existence of anti-particle. On the other hand, the solutions of quaternionic rotational momentum are obtained which shows the motion of rotating particles and anti-particles in spin up and spin down states. We have also expressed the quaternionic continuity equation for rotational energy and rotational momentum, where these continuity equations represent the conservation of four-current density. To considering the wave nature of Dirac-particles (or anti-particles), we have studied the general form of quaternionic wave function and developed the quaternionic form of rotational frequency and wave vector for particles and anti-particles. Therefore, the present thesis deals with the quaternionic quantum theory for spin-1/2 fermions and anti-fermions with rotating motion.ThesisItem Open Access Quaternionic formalism of curvature space-time and Einstein field equation(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-08) Goutam, Manisha; Chanyal, B.C.In present work, the four-dimensional quaternionic algebra has been used to describing the space-time geometry in curvature form. The properties of pure quaternion are expressed using the transformation of vector basis from one frame to another. Further, we have expressed the transformation of quaternionic variable with the help of basis transformation of quaternion. The transformation of quaternionic scalar and vector derivatives has been shown. We deduced the quaternionic covariant derivative that explains the change in quaternionic components with respect to scalar and vector components. We have also derived covariant derivative for quaternionic tensor of rank-2. An additional term appeared in the transformation known as quaternionic Christoffel symbol which explain the change from one tangent plane to another. The quaternionic metric tensor has been discussed to describing the line element in quaternionic curved space-time. We also expressed the quaternionic geodesic equation for the curved spacetime. We deduced the expression for Christoffel symbol and the Riemannian Christoffel curvature tensor in terms of quaternionic metric tensor. We have also described the energymomentum tensor in terms of quaternion. Finally, form these expressions we have proposed the quaternionic form of Einstein field equation.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, Gagan