Academy of Science of South Africa (ASSAf): Open Journal Systems
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Three-dimensional image quality test phantom for planar X-ray imaging
No full textWe aimed to produce a simple, inexpensive 3D printed phantom as a prototype for image quality assessment of contrast, contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and resolution in planar X-ray imaging systems. The test phantom was designed using SOLIDWORKS software, printed with a polylactic acid material and filled with paraffin wax. Circular aluminium sheets were used as inserts for contrast evaluation. A planar X-ray system was used for imaging and DICOM images were evaluated using ImageJ software. We evaluated spatial resolution, contrast, CNR and SNR. For resolution, full width at half maximum (FWHM) was measured on different grid sizes. For contrast, intensity of grey values and standard deviation were calculated on the different grid sizes. For CNR and SNR, difference in greyscale of investigated tissue and background per standard deviation of noise in the background was calculated. Resolution of the system was evaluated to be 1.57 and 1.80 lp/mm on grids A and B respectively. Contrast showed differential attenuation per variation in thickness. CNR increased from −13.7 for a thickness of 0.00 mm to 24.90 for a thickness of 28 mm. CNR did not change for a thickness greater than 16.0 mm. The SNR of the system fell in the acceptable range of ≥ 5 . The results from the analyses performed indicate that the test phantom has great potential to be a good substitute for the commercially available phantoms on the market, especially for low-resource settings.
Significance:This study highlights the emergence of 3D printing technology and its suitability within radiology and medical physics for the production of cost-effective phantoms which can serve as substitutes for commercial phantoms in low-resourced medical facilities in low- and middle-income countries
Development of a procedure and tool for retrofit hydropower evaluation at South African dams
No full textSouth Africa is in a critical power situation and is in dire need of additional generation capacity. Thus, renewable energy sources such as wind, solar and hydropower should be evaluated to identify high-potential and cost-effective sites. Rivers in South Africa, as a water-scarce country, are already heavily impounded, meaning that there are limited sites available for conventional hydropower generation. Instead, novel solutions such as retrofitting hydropower installations to existing infrastructure, like existing dams, are required. To estimate the retrofit hydropower potential at dams, a set of five tools was developed using Python 3, known as the University of Pretoria Retrofit Hydropower Evaluation Software (UP-RHES). The UP-RHES screens potential sites where historic flow records are available, then downloads the required flow records from the national database and performs a first-order hydraulic assessment of the site, as well as a first-order life cycle cost analysis. By applying the UP-RHES to 118 dams operated by the Department of Water and Sanitation (DWS), it was found that a total estimated hydropower potential of 128 MW with an annual energy output of between 385 and 469 GWh exists at South African dams. The Vaal, Pongolapoort, Goedertrouw and Blyderivierpoort Dams were found to be feasible sites with a combined capacity of 77 GWh/annum
Dentists have an obligation to expand their knowlodge and to contribute to knowledge
Get PDFDentistry is shaped by dental research, which also drives innovation and improves oral health outcomes. As dental scientists are at the forefront of knowledge, it is important to understand their role in pushing the boundaries of research. Dentistry as a whole must promote the value of developing and funding dental research in South Africa; and draw attention to the urgent need to pay more attention to translational research. We should also emphasize the academic obligations of dental schools and faculty to advance knowledge and contribute to the literature in parallel to the provision of much needed dental services to the people of South Africa
A CRITICAL APPRAISAL OF THE PRINCIPLES RELATING TO MISTAKE AND MISREPRESENTATION AS FACTORS AFFECTING CONSENSUS IN CONTRACTUAL AGREEMENTS IN THE NAMIBIAN CONTEXT: DISCUSSION THROUGH THE USE OF EXAMPLES
No full textThis article suggests that when those engaging in commercial undertakings have a proper understanding of the principles of the law of contract, particularly, the law pertaining to consensus, they will limit the risks of engaging in conduct that will cause them financial loss. The definitions of mistake and misrepresentation (being factors affecting consensus) need to be amplified to avoid existing confusion between the two terms. Misrepresentation and mistake may lead to different respective outcomes and possible remedies, thus necessitating a proper distinction between the two terms. In this light, the article explores and proposes similarities and differences between mistake and misrepresentation. The article further emphasises the fact that misrepresentation involves some form of incorrect representation of facts, whereas in the case of mistake, there is essentially no incorrect representation. Mistake can be said to involve misapprehension of given information, although such information may not be incorrect. It is submitted that the courts should go further than merely looking at the black-and-white before them; they must also pay attention to the conduct of the parties, the intention of the parties and the resulting consequences
GET WITH THE BEAT! THE REGULATION OF UNDERWATER NOISE IN SOUTH AFRICA
No full textAnthropogenic noise in the oceans, including from shipping and seismic surveys, is of concern as it often adversely impacts marine life and biodiversity. It is considered to be the number-one ocean pollutant today. The authors review major international legal instruments regarding underwater noise as a marine pollutant and examine them in the South African context. The authors find, inter alia, that a distinction between substance-based pollution (such as chemical pollution) and energy-based pollution (such as noise) is currently lacking. It is also found that very little literature is available on the impacts of shipping and seismic noise on small fish, turtles and cetaceans, a state of affairs that calls for a precautionary approach. It is recommended: (1) South African legal instruments that regulate underwater noise should be revised and aligned with international legal frameworks; (2) more scientific research should be conducted on the cumulative impacts of shipping and seismic surveys on the South African marine environment; and (3) the public participation process should be effectively monitored to ensure full compliance with the requirement to consult all affected and interested persons. Doing so would have wider implications for developments in the western Indian Ocean region regarding shipping, port construction and seismic explorations
DEVELOPING THE LAW CURRICULUM TO MEET THE NEEDS OF THE 21ST CENTURY LEGAL PRACTITIONER: A SOUTH AFRICAN PERSPECTIVE
No full textThe law curriculum in African countries must reflect the realities of the needs of their own societies, but law faculties and law schools in developing countries also need to equip their law graduates to deal with the wave of globalization sweeping the world. This is particularly important for countries in transition from dictatorship to democracy, and from closed to open societies. Using South Africa as an example, it is intended to deal briefly with the changes made to the law curriculum to meet the domestic needs of the new democratic order. Thereafter, the broader curriculum needs of aspiring African lawyers in the 21st century, again with reference to South Africa, will be considered in the context of globalization
OF RENT COLLECTORS AND DEBT COLLECTORS
No full textThis note examines the question whether an estate agent collecting or receiving monies in the course of his or her business as an estate agent is also a “debt collector” as defined in the Debt Collectors Act 114 of 1998. The matter is of some importance: if the answer is in the affirmative it would mean that estate agents mandated to collect rentals, levies or other monies payable in terms of sale or lease transactions must register with both the Estate Agency Affairs Board (“the Board”) in terms of the Estate Agency Affairs Act 112 of 1976 and the Debt Collectors Council (“the Council”) in terms of the Debt Collectors Act. They will have to pay levies to both the Board and the Council and comply with the codes of conduct published by both statutory bodies. Improper professional conduct may lead to disciplinary action instituted by either the Board or the Council, or both. They will have to open and keep two trust accounts (one in terms of s 32 of the Estate Agency Affairs Act and the other in terms of s 20 of the Debt Collectors Act) and will often be confused as to which monies must be paid into which of these accounts
Regionalism and the fight against terrorism in southern Africa: reflections on Cabo Delgado in Mozambique
No full textPost-independence Africa has often depicted Southern Africa as a formidable region spared by the calamities of Islamic insurgencies and terrorism. However, unfolding events in the last five years have demonstrated the limitation of SADC to terrorism exceptionalism. A combination of relatively weak states perpetuating poor regionalism, ethnic and religious diversity, poverty and the existence of the ‘ungoverned space’ are possible explanations in making the region a suitable habitat for insurgency groups. The recent invasion by terrorists of Cabo Delgado province in Mozambique has been a critical cause for concern for the stability of the region. The military intervention of the Southern African Development Community Mission in Mozambique (SAMIM) and Rwanda presents an opportunity for academics to explore regional prospects for peace and security. This paper uses insights gained from a qualitative study on terrorism, counterterrorism and regionalism to investigate the concept of regional security cooperation in the SADC region and the authenticity of institutional responses in Northern Mozambique. The study concludes that the launch of the SAMIM, despite several obstacles, represents a step in the right direction. More so, creating durable security institutions is the starting point towards realising meaningful regional security cooperation, which guarantees feasible regional economic integration. 
