Browsing by Author "Waswa, Michael Nakitare"

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Activity Concentration and Associated Radiation Dose in Machinjoni Dumpsite in Trans-Nzoia County, Kenya.
(International Journal of Novel Research and Development, 2023-09-22) Barasa, Ezekiel Simyu; Waswa, Michael Nakitare; Ouma, Linda
The activity concentration in Machinjoni dumpsite has been investigated. Activity concentration was measured using a 76 mm x76 mm NaI (Tl) detector using gamma ray spectrometry technique and various radiological parameters calculated to quantify the level of radiological hazardousness posed by the dumpsite on those interacting with the dumpsite. The mean activity concentration of 238U, 232Th and 40K in the dumpsite were 16±0.83 BqKg-1, 68±3.4 BqKg-1 and 60±3 BqKg-1 respectively. 232Th exceeded the permissible limit of 45 BqKg-1 while 238U and 40K were within permissible limits. The radiological hazard calculated in this study was absorbed dose rate. The calculated values of absorbed dose rate ranged from 29±1.45 to 140±7.03 nGyhr-1 with a mean of 51±2.56 nGh-1 and were lower than the world mean value of 84 nGhr-1. From the values it can be seen that there is significant radiation it parts of the dumpsite even though the mean values were all below permissible world values.
Assessment of Natural Radionuclides in the Top Soil Sample of Ahero Fields, Kenya
(International Journal of Modern Developments in Engineering and Science, 2023-05-22) Mukanda, Kere Wanyama; Waswa, Michael Nakitare; Ouma, Linda Immaculate
A total of 17 soil samples of Ahero fields were collected at a depth of 15 – 20 cm; five samples each of mass 170g were collected from field 1, 2, 3 and two samples from field 4. The field 1 was where rice seedlings were already transplanted, field 2 was one in which transplanting was being done, field 3 was one in which rice had been harvested and the field had just been ploughed while field 4 was a field in which farming had not been done for two years. The activity concentrations were measured, identified and detected using NaI(Ti) detector that were used in calculation of Radium Equivalent, External Hazard Indices and Internal Hazard Indices. The average radium equivalent were 185.82 ± 7.04 Bq/kg, 119.19 ± 5.95 Bq/kg, 168.78 ± 8.44 Bq/kg and 208.81 ± 10.44 Bq/kg for fields 1, 2, 3 and 4 respectively. The average internal hazard index was 0.50 ± 0.02 mSv/y, 0.32± 0.01 mSv/y, 0.45 ± 0.03 mSv/y and 0.57± 0.03 mSv/y for fields 1, 2, 3 and 4 respectively. On the other hand, the average external hazard indices for the fields were 0.59 ± 0.02 mSv/y, 0.37± 0.01 mSv/y, 0.54± 0.02 mSv/y and 0.65± 0.03 mSv/y for fields 1, 2, 3 and 4 respectively. Generally, the results from the study indicate that the radiological health risk associated with the top soils of the studyarea is insignificant.
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.
Monitoring of Annual Effective Dose (Aed) in Surface Soils of Ahero Rice Fields, Kenya
(Journal of Engineering and Technology for Industrial Applications, 2023-12-30) Wanyama, Mukanda Kere; Waswa, Michael Nakitare; Ouma, Linda Immaculate
The annual effective doses (AED) both AED (in) and AED (out) in the surface soils of Ahero rice fields, Kenya were investigated. The associated health risk of the soils from the four fields Field 1, Field 2, Field 3 and Field 4 was measured using gamma ray spectrometric technique employing Sodium Iodide Thallium doped detector. Five surface soil samples were collected at a depth of 15 – 20 cm from the Field 1, Field 2, Field 3 and two samples from Field 4. The average AED (in) of 0.30 ± 0.01 mSv/y and an average AED (out) of 0.20 ± 0.01 mSv/y for field 1, an average AED (in) of 0.19 ± 0.01 mSv/y, an average AED (out) of 0.20 ± 0.01 mSv/y for field 2, an average AED (in) of 0.28 ± 0.01 mSv/y and an average AED (out) of 0.18 ± 0.01 mSv/y for field 3 and an average AED (in) of 0.34 ± 0.01 mSv/y and an average AED (out) of 0.23 ± 0.01 mSv/y for field 4. All the AED values both in and out from the four fields were below the recommended level of 1mSv/y. The values indicate that there is no health hazard associated with the surface soils of the study area to the farmers and the general population.
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.
Radiological Risk Assessment of 238u, 232th And 40k in the Top Soils of Ahero Paddy Fields of Kisumu County, Kenya
(Journal of Engineering and Technology for Industrial Applications, 2022-08-22) Mukanda, Kere Wanyama; Waswa, Michael Nakitare; Ouma, Linda Immaculate
A radiological risk assessment of 238U, 232Th and 40K in the top soils of Ahero paddy fields of Kisumu County has been measured using NaI(TI) gamma ray spectroscopy. A total of 17 samples were collected at a depth of 15 - 20 cm and measured for activity concentrations of three radionuclides which were used to calculate the absorbed dose rates and Annual effective dose rates of the samples. Samples were collected from fields at various stages of farming process i.e., four (4) weeks after transplanting (field 1), during transplanting (field 2), after harvesting and land ploughed (field 3) and a control field (field 4) where rice farming had not been done for 2 years. The average activity concentrations for the three radionuclides for field 1 were 32.63 ± 1.63 Bq/kg for 238U, 104.69 ± 5.20 Bq/kg for 232Th and 75.00 ± 3.2 6 Bq/kg for 40K. The average activity concentrations of the radionuclides from field 2 were 16.97 ± 0.84 Bq/kg, 68.03 ± 3.40 Bq/kg and 70.31 ± 3.51 Bq/kg for 238U, 232Th and 40K respectively. The average activity concentrations of the radionuclides from field 3 (post harvesting) were 28.92 ± 1.44 Bq/kg, 91.73 ± 4.58 Bq/kg and 122.60 ± 6.13 Bq/kg for 238U, 232Th and 40K respectively. The average activity concentrations of the radionuclides were 29.74 ± 1.48 Bq/kg, 121.11 ± 6.05 Bq/kg and 87.51 ± 4.37 Bq/kg for 238U, 232Th and 40K respectively. The average Absorbed Dose Rates were 81.50 ± 4.07 nGy/h for field 1, 52.59 ± 2.62 nGy/h for field 2; 74.68 ± 3.73 nGy/h for field 3 and 91.79 ± 4.59 nGy/h for field 4. The values were below the permissible limit of 1500 nGy/h, thus the radiological risk associated with the top soils of the Ahero Paddy fields of Kisumu County, Kenya is insignificant.
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.