Browsing by Author "Waswa, Michael Nakitare"

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Effect of Internal Energy on Specific Heat of Cuprates using s-Wave and d-Wave Hybrid Model
(International Journal of Research and Innovation in Applied Science, 2020-07-05) Wanyonyi, Andrew Munyasia; Waswa, Michael Nakitare; Makokha, John Wanjala
The observation of an exponential decay of the specific heat at low temperatures shows that specific heat (Cv) of cuprates depend on the energy spectrum of a superconductor. This means that devising ways of varying internal energy of a system without necessarily varying temperature can help achieve room temperature superconductivity. In this paper, the relationship between internal energy and specific heat is investigated using a Hamiltonian generated from a Hybrid of swave and d-wave. The Hamiltonian was diagonalized by Bogoliubov-Valatin (BVT) formalism and used to analyze specific heat of Bismuth cuprates. The graph of Cv versus temperature was a skewed Gaussian shaped curve. Maximum Cv was observed at Tc (32 K, 94 K and 108 K) respectively as 2750 eV/K, for Bi-2201, Bi-2212 and Bi-2223. Increasing the number of copper oxide layers can therefore help increase binding energy and increase the temperature at which maximum Cv of the system is attained, a prerequisite for attaining high transition temperature (Tc). As a consequence, room temperature superconductivity can be achieved by varying the binding energy (increasing copper oxide planes) in a lattice of a cuprate superconductor.
Internal Energy Of Hybrid S-Wave And D-Wave Pairing In Bismuth Cuprates
(Journal of Multidisciplinary Engineering Science and Technology, 2020-06-05) Wanyonyi, Andrew Munyasia; Waswa, Michael Nakitare; Makokha, John Wanjala
Bogoliubov-Valatin Transformation was used to diagonalize a Hybrid Hamiltonian for electron-electron and electron-cooper pair interaction. From the diagonalized Hamiltonian, an expression for ground state energy was obtained and used to determine internal energy of the system of Bismuth cuprates. It was noted that the internal energy of Bi-2201 is higher than of Bi-2212 and Bi-2223. At experimental transition temperature (Tc) (20 K, 95 K and 110 K), internal energies were recorded as 0.4843 eV, 0.010 eV and 0.0058 eV. While at room temperature (300 K), internal energy was found to be 0.9528 eV, 0.2323 eV and 0.1514 eV respectively for Bi-2201, Bi-2212 and Bi-2223. The observations are discussed with a view of explaining the cause for high temperature superconductivity which can help in achieving room temperature superconductivity. Considering this model, high Tc superconductors can be identified and used to model room temperature superconductors.
Natural Radioactivity and External Dose Rates in Tailing Samples from Rosterman Gold Mine, Kakamega County, Kenya
(Journal of Engineering and Technology for Industrial Applications, 2020-12-11) Wanyama, Conrad Khisa; Makokha, John Wanjala; Masinde, Fred Wekesa; Waswa, Michael Nakitare
In this article, documented results of natural radionuclide concentrations in tailings at Rosterman gold mine, Kakamega county, Kenya were evaluated. Thirty tailing samples from Rosterman gold mine were collected as per standard sampling procedures and were analyzed for 238U, 232Th and 40K by NaI (TI) gamma-ray spectroscopy. The activities of 238U, 232Th and 40K was found to vary from 39 ± 1.63 Bq/Kg to 118 ± 4.43 Bq/Kg, 72 ± 2.24 Bq/Kg to 223 ± 8.36 Bq/Kg and 85 ± 3.6 Bq/Kg to 362 ± 10.65 Bq/Kg respectively. Radium equivalent activities were found below 370 Bq/Kg in all the collected samples. External gamma dose rates estimated from the levels of radionuclides in tailings had a range of 32 ±3.4 nGy/h to 68 ± 5.83 nGy/h. Hence, mining of gold at Rosterman has minimal significant health implications to the general population and the miners.
Superconducting Transition Temperature within the Modified Bose- Fermi-Hubbard Model
(International Journal of Progressive Research in Science and Engineering, 2021-06-04) Waswa, Michael Nakitare; Makokha, John Wanjala
Determining the conduction mechanism that would raise the TC of cuprate high temperature superconductors remains a puzzle. Here, we modify the existing Bose-Fermi-Hubbard model, diagonalize it using Bogoliubov-Valatin Transformation in order to determine the Transitional temperature, TC of hole doped-(𝑌𝐵𝑎2𝐶𝑢3𝑂7 and 𝐿𝑎2−𝑥 𝑆𝑟𝑥𝐶𝑢𝑂4 & electron-doped- (𝑁𝑑2−𝑥 𝐶𝑒𝑥𝐶𝑢𝑂4and 𝑃𝑟2−𝑥 𝐶𝑒𝑥𝐶𝑢𝑂4) cuprates. Our model predicts enhanced TC values and hence it lays a very good platform in the study of high-TC superconductivity.