Book Chapters

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2D MXenes nanomaterials for removal of organic wastewater contaminants
(CRC Press, 2024-12) Mdlalose, Lindani M; Hlekelele, Lerato; Chauke, Vongaini P
The research and development of two-dimensional (2D) materials was prompted and advanced after the discovery of the remarkable physical properties of single/multiple layered graphene. This hastily encouraged more research on 2D materials in the form of manipulating the structure of graphene through exfoliation, altering the starting material with readily available layered precursors such as graphite-like hexagonal boron nitride or dichalcogenides or even layered oxides [1]. This then stimulated the development of more 2D materials including the birth of MXenes. MXenes are a group 2D transition metal carbides, carbonitrides, and nitrides discovered in 2011 [2]. Their single flakes are denoted by a chemical formula Mn+1 Xn Tx (n = 1 to 4), which designates transition metals alternating layers (M) enclosed by carbon/nitrogen (X) layers with attached terminations Tx (-O2 , -F2 , -OH2 , -Cl2 ) on the external transition metal surfaces [3]. Due to their intriguing electrical and optical properties, they play numerous roles in photodetectors. Additionally, their distinctive mechanical, chemical, and physical properties allow MXenes to be altered by various surface terminations and transition metals. The atomically narrow structure of 2D MXenes makes it an appropriate alternative material for water purification technologies. Additionally, its large surface area, excellent mechanical strength, and numerous functional groups on their surfaces make it a suitable candidate for the uptake of contaminants from aqueous medium [4]. MXenes water purification interest is facilitated by its unique adsorptive, antibacterial, and reductive properties, which are further augmented by high electrical conductivity. With the intensive industrialization and vast agricultural systems, the release of toxic contaminants into ground and surface water continues to be a strain on the environment. In this chapter, the potential use of 2D MXenes derivatives for organic contaminants (such as dyes, antibiotics, and pharmaceuticals) removal is addressed. This entails mechanistic pathways of using MXene-based materials as adsorbents, water purification membranes, and photocatalysts. The ability of MXenebased composites in showing catalytic activity toward diverse pollutants and superior selectivity toward specific pollutants will be discussed.
5.9 - Modelling estuaries in data-poor environments
(Elsevier, 2024-03) Scharler, UM; Gerber, G; Taljaard, Susan; Mackay, F
Models are inherently data-hungry for the construction, calibration, validation and predictive capacity that is demanded of models. In data-poor environments, a severe challenge to modelling is the lack of historic data, and present lack of sufficient monitoring programmes of important variables and number of estuarine ecosystems. This is largely due to lack of infrastructure, skills, political will, and monetary support. However, environmental challenges do not wait for adequate datasets to arrive to inform decision-making, and therefore different pathways to modelling that inform both research and management are needed. We present approaches to water quality, ecosystem modelling and climate change research in South African estuaries, as a representative of a data-poor environment. Such approaches aim to use available data in novel ways to inform research and decision-making, and identify data and information gaps. We propose that such methods be used in other data-poor areas with similar types of estuaries as South Africa and we provide recommendations how to construct, validate and use models and their outcomes. The communication of model uncertainty for research purposes and to decision-makers takes an important place in such endeavours.
The Academic SDI—Towards understanding spatial data infrastructures for research and education
(Springer, 2017-05) Coetzee, S; Steiniger, S; Köbben, B; Iwaniak, A; Cooper, Antony K
The demand for geospatial data across different disciplines and organisations has led to the development and implementation of spatial data infrastructures (SDI) and the theory and concepts behind them. An SDI is an evolving concept about facilitating and coordinating the exchange of geospatial data and services between stakeholders from different levels in the spatial data community. Universities and other research organisations typically have well-established libraries and digital catalogues for scientific literature, but catalogues for geospatial data are rare. Geospatial data is widely used in research, but geospatial data produced by researchers is seldom available, accessible and usable, e.g., for purposes of teaching or further research after completion of the project. This chapter describes the experiences of a number of SDI implementations at universities and research institutes. Based on this, the Academic SDI, an SDI for research and education, is defined and its stakeholders are described. The purpose, scope and stakeholders of the Academic SDI are described based on the formal model of an SDI developed by the International Cartographic Association (ICA) Commission on SDIs and Standards (formerly the Commission on Geoinformation Infrastructures and Standards). The results contribute to understanding the state-of-the-art in SDI implementations at universities and research institutes; how the Academic SDI differs from a ‘regular’ SDI; and which role players need to be involved in a successful SDI implementation for research and education.
Accelerating the green agenda through innovative building technologies
(Alive2Green, 2015-08) Van Wyk, Llewellyn V
This chapter flows out of study (CSIR 2013b) prepared for the Presidential Infrastructure Coordinating Commission (PICC) in May 2013 which prepared a value proposition for the use of Innovative Building Technology (IBT) for the construction of clinics, schools, and student residences. The aim of the study was to encourage innovation in the building industry as a means of accelerating green building. Green building rating systems include, as part of their objectives, demonstrating leadership to the building industry with regard to improving the environmental performance of buildings. The Green Star rating system is advocated on the following premise (GBCSA 2015): a) Establish a common language and standard of measurement for green buildings; b) Promote integrated, whole-building design; c) Raise awareness of green building benefits; d) Recognise and reward environmental leadership; and e) Reduce the environmental impact of development.
Achievable capacity limit of high performance nodes for wireless mesh networks
(InTech, 2012-08) Olwal, T; Masonta, Moshe T; Mekuria, Fisseha; Roux, K
Next generation fixed wireless broadband networks have immensely been deployed as mesh networks in order to provide and extend access to the internet. These networks are characterised by the use of multiple orthogonal channels. Nodes in the network have the ability to simultaneously communicate with many neighbours using multiple radios over orthogonal channels thereby improving effective and "online" channel utilisation. Many such networks emerging from standards such as IEEE 802.11 a/b/g/n and 802.16 are already in use, ranging from prototype test-beds to complete solutions. The increasing question is how the theoretical capacity of such static multi-radio multi-channel (MRMC) network scales with the number of nodes and the irregularity of the deployment terrain. In their seminal work, Gupta and Kumar (2000) determined the capacity of single radio single channel in arbitrary networks. Their findings have been later extended to derive the capacity bounds of the MRMC configurations by Kyasanur and Vaidya (2005).
Active nanocomposite films based on low density polyethylene/organically modified layered bouble hydroxides/thyme oil to retain retail shelf life and quality of hass avocados
(2020-11) Kesavan Pillai, Sreejarani; Sivakumar, D; Ray, SS; Obianom, P; Eggers, SK; Mhlabeni, T
In this study, the ability of an active film containing volatile bioactives in post-harvest disease control and preservation of quality in avocados is explored as a non-traditional treatment method. Antimicrobial transparent flexible trilayer low density polyethylene (LDPE) films containing organically modified layered double hydroxides (OLDH) and plant bioactive-thyme oil (TO) were made using single step blown film extrusion. Antifungal effects of the packaging in comparison to commercial treatment and untreated control showed considerable reduction in anthracnose disease events in ‘Hass’ cultivar of avocados while improving the fruit quality. 2wt% OLDH loading improved the oxygen and moisture barrier properties while not affecting the transparency of the film. The results suggest that the synergistic effect of barrier and antimicrobial properties of the controlled volatile bioactive release of the nanocomposite film can be utilised as a prospective strategy to modify the headspace gas composition to combat anthracnose disease in avocados.
Adaptation and mitigation: synergies and trade-offs
(CSIR, 2017-10) Thambiran, Tirusha; Naidoo, Sasha
Typically, mitigation and adaptation research has been developed separately, with the mitigation research community focused on taking a global approach to limiting cumulative greenhouse gas (GHG) emissions. The adaptation research community, however, emphasises locally-focused analysis aimed at minimising the impacts of climate change, especially within the most vulnerable communities. International climate policy has historically developed with a focus on mitigation, though in recent years increased attention has been placed on adaptation. For example, at the 21st Conference of the Parties (COP-21) to the UN Framework Convention on Climate Change, countries also committed toward adaptation responses within their Nationally Determined Contributions.
Adapting to global change in a diverse landscape: the Kruger to Canyons Biosphere Reserve
(The Department of Science and Technology, 2010-04) Davis, C; Archer, Emma RM; Maserumule, R; Stevens, N; Sinden, LA
This study will draw on the findings of a significant amount of research that has already taken place in the area. There is a keen desire amongst diverse stakeholders to access global change information (for example, the use of such information to inform the Bushbuckridge Municipality IDP), as well as to interactively develop an understanding of what global change implies for critical sectors in the area.
Adding functionality to garments
(Elsevier, 2014-11) Hunter, Lawrance; Fan, J
Consumers expect the garments they buy to meet a multiplicity of end use and wear conditions, and this means manufacturers need to build functionality, or multifunctionality, into the garments they produce. This chapter discusses the ways in which various functionalities, such as retention of appearance, durability, comfort, handle and tailorability can be enhanced in garments. The tests used to assess and quantify the different functionalities are described.
Advanced fire information system
(Group on Earth Observations, 2007) Frost, PE; Scholes, RJ
The South African Advanced Fire Information System (AFIS) is the first near real-time satellite-based fire monitoring system in Africa. It was originally developed for, and funded by, the electrical power utility Eskom, to reduce the impact of wild fires on regional electricity supply.1 Fires underneath the 28,000 km of power lines can cause flashovers which severely affect electricity supply. The loss of life and destruction of property caused every year by wildfires further emphasised the need to develop an operational, early warning fire information system that could alert the disaster management, fire-fighting, farming and forestry communities on the location and trajectory of blazes, as well as capturing information on the frequency and distribution of fires for researchers.
Advanced walling systems
(Alive2green Publishers, 2010-01) De Villiers, A
The question addressed by this chapter is: How should advanced walling systems be planned, designed, built, refurbished, and end their useful lives, to classify as smart, sustainable, green or eco-building environments?
Advancing mouth management practices in the Groot Brak Estuary, South Africa
(Delft Academic Press, 2020-02) Van Niekerk, Lara; Adams, JB; Taljaard, Susan; Huizinga, Piet; Lamberth, S; Slinger, J; Taljaard, Susan; D'Hont, F; Mittal, A
The early 1990s in South Africa were characterised by a strongly hierarchical and technocratic regime where planning and development decisions regarding the environment were made at national government level with little or no public consultation (Slinger et al., 2005). One such a decision was the construction of the 70 m high and 270 m wide Wolwedans Dam (with a capacity of 23 × 106 m3) only 3 km upstream of the Groot Brak Estuary (also known as the Great Brak Estuary) by the South African Department of Water Affairs and Forestry (DWAF) (Figure 6.1). However, then the local community of the Town of Groot Brak feared the effects of reduced water supply on the health of the estuary, as well as the risk of flooding during dam failure. Increasing public pressure, and consequent media coverage, culminated in the DWAF setting up a steering committee, the Groot Brak River Environmental Committee (GEC). This committee was tasked to investigate the effect of the dam on the estuary, and to establish a management plan for the optimal use of the reserved water (1 x 106 m3) to maintain current ecological health. The Council for Scientific and Industrial Research (CSIR) were commissioned to undertake this assessment (CSIR, 1990; Slinger et al., 2005).
Aerosol measurements over South Africa using LIDAR, Satellite and Sun Photometer
(World Scientific Publishing Company, 2010-05) Sivakumar, V; Tesfaye, M; Alemu, W; Sharma, Ameeth; Bollig, C; Mengistu, G
In this study, the authors present the climatological picture of aerosols over South Africa using 20 years of Stratosphere Aerosol and Gas Experiment (SAGE-II) satellite, 6–10 years of AErosol RObatic NETwork (AERONET) and ground based mobile LIDAR datasets. The climatological variation of aerosol concentration indicate minimum during winter and maximum over September months. The satellite and ground based measurements are found to be in good agreement with each other. The study affirms the presence of fine and accumulation mode aerosols over industrial areas of South Africa
Africa's technology options for renewable energy production and distribution
(Africa Institute of South Africa, 2011-12) Amigun, B; Kaggwa, M; Musango, J; Mutanga, Shingirirai S; Simelane, T; Stafford, William HL
This chapter presents a critical appraisal of Africa's modern energy technologies for renewable energy. It highlights issues of scale and location-specific attributes. A critical review of different renewable energies is presented, the state of renewable energy technologies in Africa is discussed and country-specific examples and classifications are listed.
The African perspective I: Using the new biosciences to support the African development agenda
(Taylor & Francis Group publishers, 2016-09) Morris, EJ; Erasmus, C; O'Kennedy, Maretha M
Biopharmaceutical proteins and vaccines are traditionally produced in bacteria, eggs, yeast and animal cell cultures and are well established industries. More recently, these molecules are produced in plants and became known as biopharming. Plant-based production systems have the advantages of eukaryotic protein processing properties, inherent safety due to a lack of adventitious agents, substantial cost reduction and facile scalability. The latter was demonstrated in two therapeutic and industrial enzyme technoeconomic case studies (Tusé et al., 2014). These advantages however are molecule/product-specific and depend on the relative cost-efficiency of alternative sources of the same product (biosimilars) or improved products (biobetters). Nevertheless, plant-based manufacturing is estimated to reduce the running costs (20-25%) and capital expenses (40%) compared to animal cell-based processes (Gleba and Giritch, 2012). A facility with the capacity of 1 ton of antibody per year would cost less than $50 million and operation costs for the first 3 years would amount to $45-60 million (Gleba and Giritch, 2012). Such a low financial entry barrier represents a very attractive opportunity for manufacturers in developing countries (Gleba and Giritch, 2012). In addition, the Defence Advanced Research Projects Agency (DARPA) recognises that plant-based transient systems overall represent the best manufacturing technologies when dealing with bioterrorism and pandemics. Biopharming is advancing fast and numerous reviews cover the latest developments concerning vaccines (Rybicki, 2014), antibodies (Whaley et al., 2014), purification strategies (Buyel and Fischer, 2014) and manufacturing platforms (Gleba and Giritch, 2012; Klimyuk et al., 2014).
Agavaceae
(South African National Biodiversity Institute, 2019) Smith, GF; Walters, Michele; Figueiredo, E; Klopper, RR; Bredenkamp, CL
This chapter discusses the taxonomic treatment of the Agavaceae of the Eastern Cape Province.
Agriculture and livestock
(CSIR, 2017-10) Lötter, Johanna M
The agricultural sector in southern Africa needs to produce enough food to feed its current population of 277 million and future predicted population of over 300 million by 2025 (United Nations ESA, 2015). All of this must happen within the many restrictions imposed on the sector by an unpredictable climate, finite natural resources and sometimes limited access to modern production technology (Kotze & Rose, 2015). Global projections suggest that the number of people at risk of hunger will increase by 10 to 20 percent by 2050 as a result of climate change, with 65 percent of this population in sub-Saharan Africa.
Air quality
(AFRICAN SUN MeDIA, 2017-12) Thambiran, Tirusha; Padayachi, Yerdashin R
This chapter provides an overview of the latest developments in air quality management and air pollution trends in South Africa. The critical issues of managing air quality in the context of climate change and risk and vulnerability, are also discussed.
Air quality and greenhouse gas emissions (Chapter 3)
(CSIR, 2016) Winkler, H; Altieri, K; Clarke, S; Garland, Rebecca M; Kornelius, G; Meas, M
Shale gas development (SGD) presents opportunities and risks with regards to air pollution and greenhouse gas (GHG) emissions. There is a potential opportunity to reduce emissions, if shale gas replaces ‘dirtier’ (more emissions-intensive) fuels, however, there is also a risk of increased emissions if shale gas is added to the existing energy mix, and displaces cleaner fuels for new capacity. Emissions of GHGs have global impacts, while impacts from air pollution are generally assessed at local and regional scales. The highest risks assessed are due to leakage of methane prior to end-use, a potent GHG; and the exposure of workers to air pollutants on the wellpad. For all three SGD scenarios considered in this assessment, the scale of SGD in South Africa is assumed to be smaller than SGD in the United States of America (USA), which results in lower estimates of air pollution and GHG emissions for South Africa as compared to the USA, even in the Big Gas scenario. An urgent priority is the early establishment of baselines (through air quality and GHG monitoring stations in the study area, and inventories for air pollutants and GHG emissions), to be followed by the design of continuous monitoring systems. Based on the scientific assessment, it is recommended that further research into the existing regulatory framework and its capacity to deal sufficiently with SGD, along with the potential to enhance institutional and human capacity be explored. Industrial activity in the study area is currently low and the need for this type of regulatory capacity does not currently exist. Good practice guidelines are needed to minimise impacts on air quality and reduce GHG emissions, with guidelines for control technologies, consideration of effective legal regulation, early establishment of baselines and continuous monitoring, and good governance enabled by coordination across several institutions.
Air quality and health
(Health Systems Trust, 2024-02) John, Juanette; Perumal, Sarisha; Mlambo, Mfundo; Naidoo, Mogesh; Ndlovu, Noluthando; Padarath, Ashnie
Exposure to polluted air causes millions of premature deaths each year and can lead to health risks such as reduced lung growth and function, respiratory infections and aggravated asthma. Many deaths related to air pollution occur in Asia and Africa and poor air quality places an additional burden on the health.

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