School for Science and Technology

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Browsing School for Science and Technology by Author "Bezuidenhout, Jacques"

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    The background radiation and exposure levels at various South African west coast military units
    (Stellenbosch University. Faculty of Military Science (Military Academy), 2014) Bezuidenhout, Jacques
    The West Coast of South Africa between St Helena Bay to the north and Langebaan Lagoon to the south is characterised by numerous granite protrusions. These outcrops are elements of the underlying Cape Granite Suite, which forms the bedrock of a large part of the Western Cape. Granite contains high levels of natural radionuclides, which results in high levels of natural background radiation in the surrounding area. The impacts of these high levels of radiation exposure on military personal are of concern. There are four military units located in this part of the West Coast, namely SAS Saldanha, 4 Special Forces Regiment, Langebaan Road Air Force Base and the Military Academy. Different sites in and around these military units were selected and soil samples were taken. Laboratory gamma ray measurements were done to determine the levels of natural radioactive nuclides in the soil samples. The radioactive nuclide concentrations were interpolated and then mapped with the help of geographic information systems (also known as geospatial information systems or GIS) software. An evaluation of the annual dose rate of military personnel at the units on the West Coast was made and found to range between 0,017 mSv/y and 0,163 mSv/y. These values were mapped and compared to the average global annual dose rate of 0,070 mSv/y. This article reports on an investigation of these results and the overall exposure levels of personnel from the various military units on the West Coast of South Africa.
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    Effect of the elemental content of shells of the bivalve mollusks (Mytilus galloprovincialis) from Saldanha Bay (South Africa) on their crystallographic texture
    (MDPI, 2021) Nekhoroshkov, Pavel; Zinicovscaia, Inga; Nikolayev, Dmitry; Lychagina, Tatiana; Pakhnevich, Alexey; Yushin, Nikita; Bezuidenhout, Jacques
    A both wild and farmed mussels in natural conditions, anthropogenic inputs are usually reflected in the increase of the content of specific elements. To determine the possible effect of the elemental patterns of farmed and wild mussels (Mytilus galloprovincialis) collected in the Saldanha Bay area (South Africa) on the crystallographic texture of the shells, the content of 20 elements in shells and 24 in the soft tissue of mussels was determined by neutron activation analysis. The crystallographic texture of mussel shells was analyzed using time-of-flight neutron diffraction. The wild mussels from open ocean site live in stressful natural conditions and contain higher amounts of the majority of determined elements in comparison with mussels farmed in closed water areas with anthropogenic loadings. The changes between the maximums of the same pole figures of the three samples are in the range of variability identified for the genus Mytilus. The content of Cl, Sr, and I was the highest in mussels from the open ocean site, which is reflected by the lowest mass/length ratio. The determined crystallographic textures of mussels are relatively stable as shown in the analyzed pole figures despite the concentrations of Na, Mg, Cl, Br, Sr, and I in shells, which significantly differ for wild and farmed mussels. The stability of the crystallographic texture that we observed suggests that it can be used as a reference model, where if a very different texture is determined, increased attention to the ecological situation should be paid.
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    Estimation of radon potential through measurement of uranium concentrations in granite geology
    (Academy of Science of South Africa, 2019) Bezuidenhout, Jacques
    The geology of an area can be used as a predictor for radon potential. Granite rock typically contains a high concentration of uranium and subsequent elevated emanation of radon gas. The geology of the western part of the Western Cape Province in South Africa is dominated by granite bedrock but very few studies on radon have been conducted in this area. Uranium concentrations were consequently measured on a large granite hill in the Saldanha Bay area of the Western Cape and a relationship between indoor radon and uranium concentrations was used to model radon potential on the outcrop. Results from granite rich environments in India were modelled in order to extract a relationship between indoor radon concentrations, radon exhalation rates and uranium concentrations. Radon exhalation rates greater than 0.35 Bq/m2h were predicted and estimated indoor radon concentrations in excess of 400 Bq/m3 were also predicted for the hill. The modelled results were compared with indoor radon measurements taken in the town of Paarl in the Western Cape, which sits on the same granite bedrock formation. The predicted radon potential correlated well with the physical measurements.
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    The investigation of radionuclides distributions in beach sand by means of GIS techniques
    (CONSAS Conference, 2015-11) Bezuidenhout, Jacques
    A transportable and robust gamma ray detection system (GISPI) was employed to determine the concentrations of naturally occurring radionuclides on various beaches in and around Saldanha Bay, located on the West Coast of South Africa. Several mathematical techniques were applied to obtain GIS overlay that could be used to investigate various geophysical phenomenon. The results demonstrated direct relationships between radionuclide concentrations, grain size of beach sediment and the intensity of wave action. The element concentrations were used to make deductions on the origin of some of the beach sand. The article finally draws conclusions on coastal and beach formation processes, based on the results of the distribution of various radionuclides.
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    The mapping and investigation of radionuclide pollution in the processing plant of a spent phosphate mine by using GIS techniques
    (CONSAS, 2018) Bezuidenhout, Jacques
    The mining and refinement of phosphate is characterised by high levels of uranium. An in situ gamma ray survey was done at the processing plant of a spent phosphate mine near Vredenburg on the west coast of South Africa in order to assess radionuclide concentrations. The concentrations of potassium, thorium and radioactive progeny of uranium were measured and plotted with the help of QGIS software. The results demonstrated high concentrations in specific areas of the plant. The highest concentrations were found to be 898 Bq/kg for potassium, 162 Bq/kg for 232Th and 639 Bq/kg for 226Ra. It was demonstrated that the refinement process technologically enhanced the naturally occurring radioactive nuclides and contaminated sections of the processing plant. The causes of the contamination were also investigated. The effective dose for the various parts of the processing plant was also estimated and the highest level was found to be 0.45 mSv/y. The article finally draws conclusions as to the environmental impact of the radiation and possible future preventative measures that could be followed in order to minimize pollution.
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    Mapping of historical human activities in the Saldanha Bay military area by using in situ gamma ray measurements
    (Faculty of Military Science, Stellenbosch University, 2012) Bezuidenhout, Jacques
    Saldanha Bay on the west coast of South Africa is surrounded by various nature reserves, military units and training sites. Over a long period of time, large parts of this semi-arid area were exposed to human activities, including military training and the preparation of forces for war. This article investigates the prospect of identifying areas where human activities took place via mapping of the variation in primordial radioactive isotopes. For this purpose, in situ gamma-ray data were obtained from selected locations around Saldanha Bay. The data were used to extract concentrations of primordial radioactive isotopes in these locations. The radioactive primordial isotope concentrations were then mapped and compared to historical evidence of human activities in these areas. The concentrations of potassium isotope showed a relationship to the height above mean sea level. Historical human activities were mainly confined to flatter regions of the area around Saldanha Bay and therefore also relate to the height above mean sea level. The potassium concentrations and the areas where human activities took place were compared and a significant relationship was found.