Pub Date : 2023-09-28DOI: 10.17159/sajs.2023/13921
Pogisego Dinake, Norma Phokedi, Mbhatshi M. Keetile, Mmamiki A. Botlhomilwe, Mogomotsi Tlhako, Bokang Present, Janes Mokgadi, Rosemary Kelebemang
The pursuit of a cost-effective and green synthetic approach to chemical sensors and their application in the sensing of toxic and harmful substances is a never-ending exercise for scientists and researchers. Preparation of fluorescent carbon dots (C-dots) from biomass using water as a solvent and a hydrothermal autoclave to provide the required synthesis temperature offers a cheap and environmentally friendly synthetic approach. Herein, we report a faster, less costly and ecofriendly hydrothermal synthetic approach of carbon dots from Citrullus vulgaris peels as a precursor. The as-prepared carbon dots exhibited hydroxyl, carbonyl and amide functional groups on the surface and an amorphous structure with a particle size distribution of 1.7–3.0 nm. Moreover, the carbon dots displayed intense blue emission fluorescence at 470 nm after excitation at 400 nm. The as-prepared carbon dots demonstrated effective application without further modification towards the selective and sensitive optical recognition of 2-nitrophenol used in the manufacture of explosives. A limit of detection of 2.28×10−7 M was achieved, and no fluorescence quenching was observed in the presence of other nitroaromatic and benzene derivatives indicating excellent selectivity towards 2-nitrophenol. Finally, further studies are required to investigate the potential for the as-prepared carbon dots to monitor nitroaromatic pollutants in real environmental systems.
{"title":"One-pot hydrothermal green synthetic approach of fluorescent carbon dots as optical probes for 2-nitrophenol","authors":"Pogisego Dinake, Norma Phokedi, Mbhatshi M. Keetile, Mmamiki A. Botlhomilwe, Mogomotsi Tlhako, Bokang Present, Janes Mokgadi, Rosemary Kelebemang","doi":"10.17159/sajs.2023/13921","DOIUrl":"https://doi.org/10.17159/sajs.2023/13921","url":null,"abstract":"The pursuit of a cost-effective and green synthetic approach to chemical sensors and their application in the sensing of toxic and harmful substances is a never-ending exercise for scientists and researchers. Preparation of fluorescent carbon dots (C-dots) from biomass using water as a solvent and a hydrothermal autoclave to provide the required synthesis temperature offers a cheap and environmentally friendly synthetic approach. Herein, we report a faster, less costly and ecofriendly hydrothermal synthetic approach of carbon dots from Citrullus vulgaris peels as a precursor. The as-prepared carbon dots exhibited hydroxyl, carbonyl and amide functional groups on the surface and an amorphous structure with a particle size distribution of 1.7–3.0 nm. Moreover, the carbon dots displayed intense blue emission fluorescence at 470 nm after excitation at 400 nm. The as-prepared carbon dots demonstrated effective application without further modification towards the selective and sensitive optical recognition of 2-nitrophenol used in the manufacture of explosives. A limit of detection of 2.28×10−7 M was achieved, and no fluorescence quenching was observed in the presence of other nitroaromatic and benzene derivatives indicating excellent selectivity towards 2-nitrophenol. Finally, further studies are required to investigate the potential for the as-prepared carbon dots to monitor nitroaromatic pollutants in real environmental systems.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135385469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-28DOI: 10.17159/sajs.2023/14320
Thamsanqa F. Wanda, Errol A. Wiles, Hayley C. Cawthra, Anton de Wit
Given a growing global population and shift to embrace the blue economy, a need for marine spatial planning (MSP) has emerged in South Africa to sustainably resolve the rising conflicts over the use of marine and seabed resources and services. A well-developed marine spatial plan yields numerous ecological, social and economic benefits. These are achieved through mediating between spatially conflicting economic drivers’ interests (e.g. commercial fishing, tourism, mining), preventing their activities from compromising thresholds of an environment’s sustainability. Within the MSP framework, high-resolution geospatial datasets are required to document and describe the seabed in the highest possible detail. At any scale, integrated analysis of seabed geomorphology and habitats is anticipated to greatly improve the understanding of ecosystem functioning from a multidisciplinary perspective, whilst improving MSP procedures and management of marine space. South Africa is the first of few African countries to have an approved and implemented MSP framework, but is still somewhat behind globally in implementing large-scale regional hydroacoustic surveys to cover the country’s vast offshore territory. The deficiency of hydroacoustic surveys is perhaps due to a relative lack of funds and poor communication about the value of multibeam echo-sounder (MBES) derived data, whilst marine geoscience remains a scarce skill in the country. This review paper presents a geological perspective of MSP and explores (1) the value that seabed mapping offers MSP specifically and (2) the need to increase seabed mapping with MBES, using a recently initiated project from the South African east coast as a case study.
{"title":"The value of multibeam bathymetry in marine spatial planning in South Africa: A review","authors":"Thamsanqa F. Wanda, Errol A. Wiles, Hayley C. Cawthra, Anton de Wit","doi":"10.17159/sajs.2023/14320","DOIUrl":"https://doi.org/10.17159/sajs.2023/14320","url":null,"abstract":"Given a growing global population and shift to embrace the blue economy, a need for marine spatial planning (MSP) has emerged in South Africa to sustainably resolve the rising conflicts over the use of marine and seabed resources and services. A well-developed marine spatial plan yields numerous ecological, social and economic benefits. These are achieved through mediating between spatially conflicting economic drivers’ interests (e.g. commercial fishing, tourism, mining), preventing their activities from compromising thresholds of an environment’s sustainability. Within the MSP framework, high-resolution geospatial datasets are required to document and describe the seabed in the highest possible detail. At any scale, integrated analysis of seabed geomorphology and habitats is anticipated to greatly improve the understanding of ecosystem functioning from a multidisciplinary perspective, whilst improving MSP procedures and management of marine space. South Africa is the first of few African countries to have an approved and implemented MSP framework, but is still somewhat behind globally in implementing large-scale regional hydroacoustic surveys to cover the country’s vast offshore territory. The deficiency of hydroacoustic surveys is perhaps due to a relative lack of funds and poor communication about the value of multibeam echo-sounder (MBES) derived data, whilst marine geoscience remains a scarce skill in the country. This review paper presents a geological perspective of MSP and explores (1) the value that seabed mapping offers MSP specifically and (2) the need to increase seabed mapping with MBES, using a recently initiated project from the South African east coast as a case study.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135344741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-31DOI: 10.17159/sajs.2023/16597
R. Inglesi‐Lotz
to
向
{"title":"Load shedding in South Africa: Another nail in income inequality?","authors":"R. Inglesi‐Lotz","doi":"10.17159/sajs.2023/16597","DOIUrl":"https://doi.org/10.17159/sajs.2023/16597","url":null,"abstract":"to","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45479359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-31DOI: 10.17159/sajs.2023/16595
M. Muller
private-sector approaches to the management of traditionally public utility functions
私营部门管理传统公用事业职能的方法
{"title":"Load shedding as a result of failures at the political-technological interface","authors":"M. Muller","doi":"10.17159/sajs.2023/16595","DOIUrl":"https://doi.org/10.17159/sajs.2023/16595","url":null,"abstract":"private-sector approaches to the management of traditionally public utility functions","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43808575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-31DOI: 10.17159/sajs.2023/16596
M. J. Booysen, S. van der Berg, Pieter W. van der Walt
Culling electrical demand to save a fickle supply costs South Africa more than you may think. Load shedding is South Africa’s new norm, affecting each of us, with individual impacts ranging from annoyance to ruin. Much of our vital and collective electrical lifeline is sacrificed on the altars of convenience, inefficiency, and oversight. This Commentary sheds light on some of the hidden costs of load shedding. We call for custodianship of this crucial and limited shared source of life, and call on government to incentivise electricity generation, preferably the renewable and distributed type.
{"title":"Some real but mostly unconsidered costs hiding in the dark corners of load shedding","authors":"M. J. Booysen, S. van der Berg, Pieter W. van der Walt","doi":"10.17159/sajs.2023/16596","DOIUrl":"https://doi.org/10.17159/sajs.2023/16596","url":null,"abstract":"Culling electrical demand to save a fickle supply costs South Africa more than you may think. Load shedding is South Africa’s new norm, affecting each of us, with individual impacts ranging from annoyance to ruin. Much of our vital and collective electrical lifeline is sacrificed on the altars of convenience, inefficiency, and oversight. This Commentary sheds light on some of the hidden costs of load shedding. We call for custodianship of this crucial and limited shared source of life, and call on government to incentivise electricity generation, preferably the renewable and distributed type.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49641528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-31DOI: 10.17159/sajs.2023/16009
C. Wright, Matthew Benyon, N. Mahlangeni, T. Kapwata, T. Laban, R. Garland
concentrations of pollutants are within acceptable levels for human health. For example, the 24-hour average standard for PM 2.5 (particulate matter with an aerodynamic diameter smaller than 2.5 µg/m 3 ) in South Africa is 20 µg/m 3 – this may be compared to the more stringent World Health Organization guideline of 5 µg/m 3 . 14 Data available on SAAQIS go through data validation processes and are checked for zero drift, which, if identified, is corrected based on values from the most recent in-situ calibration. In accordance with prescribed standard operating procedures, suspicious data spikes, negative values and other questionable data points are removed
{"title":"Data gaps will leave scientists ‘in the dark’: How load shedding is obscuring our understanding of air quality","authors":"C. Wright, Matthew Benyon, N. Mahlangeni, T. Kapwata, T. Laban, R. Garland","doi":"10.17159/sajs.2023/16009","DOIUrl":"https://doi.org/10.17159/sajs.2023/16009","url":null,"abstract":"concentrations of pollutants are within acceptable levels for human health. For example, the 24-hour average standard for PM 2.5 (particulate matter with an aerodynamic diameter smaller than 2.5 µg/m 3 ) in South Africa is 20 µg/m 3 – this may be compared to the more stringent World Health Organization guideline of 5 µg/m 3 . 14 Data available on SAAQIS go through data validation processes and are checked for zero drift, which, if identified, is corrected based on values from the most recent in-situ calibration. In accordance with prescribed standard operating procedures, suspicious data spikes, negative values and other questionable data points are removed","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46126949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-31DOI: 10.17159/sajs.2023/16602
M. Ritchie, J. Engelbrecht, M. J. Booysen
Load shedding has become the norm in South Africa. These rolling blackouts currently range from Stage 1 to Stage 6. Households are disempowered for 2–4 hours and for an average of 1.5–9 hours per day. In financially unequal South Africa, heavy users can afford battery backup solutions to keep the lights on. However, installing these at scale, without solar generation, eventually neuters the utility’s ability to stabilise the grid and avert a blackout with shedding. Here we assess and quantify the impact of these interventions using an electricity data set of 12 000 households.
{"title":"The impact of the increasing residential battery backup systems on load shedding","authors":"M. Ritchie, J. Engelbrecht, M. J. Booysen","doi":"10.17159/sajs.2023/16602","DOIUrl":"https://doi.org/10.17159/sajs.2023/16602","url":null,"abstract":"Load shedding has become the norm in South Africa. These rolling blackouts currently range from Stage 1 to Stage 6. Households are disempowered for 2–4 hours and for an average of 1.5–9 hours per day. In financially unequal South Africa, heavy users can afford battery backup solutions to keep the lights on. However, installing these at scale, without solar generation, eventually neuters the utility’s ability to stabilise the grid and avert a blackout with shedding. Here we assess and quantify the impact of these interventions using an electricity data set of 12 000 households.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41802265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-31DOI: 10.17159/sajs.2023/16594
S. Clark, C. McGregor
plan are to expedite the review and approval of the queue of 6 GW of proposed private renewable generation projects and the commitment to encourage and enable commercial, industrial and residential rooftop solar projects. Once approvals are in place, these projects can be implemented quickly at any appropriate size
{"title":"Liquified petroleum gas provides a technically viable and financially feasible means to reduce Eskom’s diesel cost burden by 30% to 40%","authors":"S. Clark, C. McGregor","doi":"10.17159/sajs.2023/16594","DOIUrl":"https://doi.org/10.17159/sajs.2023/16594","url":null,"abstract":"plan are to expedite the review and approval of the queue of 6 GW of proposed private renewable generation projects and the commitment to encourage and enable commercial, industrial and residential rooftop solar projects. Once approvals are in place, these projects can be implemented quickly at any appropriate size","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41903477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-31DOI: 10.17159/sajs.2023/16608
M. Marchetti-Mercer
limited electricity supply by installing inverters, generators and solar panels in their homes and workplaces. The constant disruptions brought about by blackouts have led to an overwhelming sense of frustration and uncertainty, as people feel they have no control of their lives and environment. Breakages, cable theft, and sabotage exacerbate the situation by adding unscheduled outages, some for as long as 10 days. Outages are also increasingly leading to water shortages as reservoirs cannot refill in the short periods between outages, and to telecommunication problems. Significantly, such disruptions in work and educational activities, as well as in the domestic domain, have been shown internationally to increase psychological distress. 7 Disruption in electricity supply potentially further affects people’s physical health, which can in turn increase people’s risk of developing mental health problems. At the most basic level, food safety is affected as constant refrigeration cannot be guaranteed, placing people at risk of food poisoning and diarrhoeal diseases. Water purification systems also require electricity to function optimally, so load shedding leaves people without water or facing the threat of contaminated water. 7 South Africa has recently experienced a cholera outbreak and the contamination of rivers and sea water in different provinces, because sewage plants did not have electricity. 8,9
{"title":"Resilience is not enough: The mental health impact of the ongoing energy crisis in South Africa","authors":"M. Marchetti-Mercer","doi":"10.17159/sajs.2023/16608","DOIUrl":"https://doi.org/10.17159/sajs.2023/16608","url":null,"abstract":"limited electricity supply by installing inverters, generators and solar panels in their homes and workplaces. The constant disruptions brought about by blackouts have led to an overwhelming sense of frustration and uncertainty, as people feel they have no control of their lives and environment. Breakages, cable theft, and sabotage exacerbate the situation by adding unscheduled outages, some for as long as 10 days. Outages are also increasingly leading to water shortages as reservoirs cannot refill in the short periods between outages, and to telecommunication problems. Significantly, such disruptions in work and educational activities, as well as in the domestic domain, have been shown internationally to increase psychological distress. 7 Disruption in electricity supply potentially further affects people’s physical health, which can in turn increase people’s risk of developing mental health problems. At the most basic level, food safety is affected as constant refrigeration cannot be guaranteed, placing people at risk of food poisoning and diarrhoeal diseases. Water purification systems also require electricity to function optimally, so load shedding leaves people without water or facing the threat of contaminated water. 7 South Africa has recently experienced a cholera outbreak and the contamination of rivers and sea water in different provinces, because sewage plants did not have electricity. 8,9","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45947455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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