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Lecturer
Name: Johannes Mvelase
Location: John Orr Building 7158 Doornfontein Campus
Physics Academic Staff Staff Members
Contact Details:
Tel: 011 559 6009
Email: mjmvelase@uj.ac.za
About Mr. Johannes Mvelase
Research Interests:
My research interests are in the field of low-energy nuclear physics, particularly for environmental protection and management. This interest ranges from the measurement of radiation in soil using gamma spectrometry to the measurement of radon in water and air using the RAD 7 detector to the investigation of toxic heavy metals in soil and water using X-ray fluorescence and related techniques.
The Earth, which is composed of various (stable and radioactive) elements, is naturally subject to nuclear decay. These decays produce gamma rays, which are picked up by scintillator or solid-state detectors.
The radon gas in water or air produces alpha particles of about 4.8 MeV, which are captured by the RAD 7 detector.
When elements are excited with high energy, they absorb the energy and jump to high states. When they return to their original position, they emit radiation that has a characteristic wavelength for the elements that transition to the ground state. This wavelength is used by X-ray fluorescence to quantify the elements that are among the main pollutants in soil.
Selected Research Publications:
1. Mvelase, M.J. and Masiteng, P.L., 2023. Quantification of toxic metals in cropland soil using X-ray fluorescence. South African Journal of Science, 119(9-10), pp.1-7.
https://www.scielo.org.za/pdf/sajs/v119n9-10/22.pdf
2. Reddy, L., Letswalo, M.L., Sefage, A.P., Kheswa, B.V., Balakrishna, A., Changundega, J.M., Mvelase, M.J., Kheswa, K.A., Majola, S.N.T., Mathe, T. and Seakamela, T., 2022. Integrity vs. Quality of Assessments: Are They Compromised on the Online Platform?. Pedagogical Research, 7(2).
https://files.eric.ed.gov/fulltext/EJ1337299.pdf
3. Mvelase, M.J., Masiteng, P.L. and Mavunda, R.D., Radiological Assessment of Weenen farmland Samples, KwaZulu-Natal, South Africa.
https://events.saip.org.za/event/144/papers/1551/files/956-2019_SAIP_Mvelase.pdf
4. Ongori, J.N., Lindsay, R. and Mvelase, M.J., 2015. Radon transfer velocity at the water–air interface. Applied Radiation and Isotopes, 105, pp.144-149.
https://doi.org/10.1016/j.apradiso.2015.07.058
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