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Parsimonious Airfoil Parameterisation: A Deep Learning Framework with Bidirectional LSTM and Gaussian Mixture Models
Get PDFJournal Article, Faculty of Engineering, Multilingual Speech Technologies (MUST)-- Potchefstroom CampusThe choice of airfoil parameterisation method significantly influences the overall wing optimisation performance by affecting the flexibility and computational efficiency of the process. Ideally, one should be able to intuitively constrain airfoil shape and structural characteristics as input to the optimisation process. Current parameterisation techniques lack the flexibility to generate airfoils efficiently by specifying parsimonious shape and structural features. To address this limitation, a deep learning framework is proposed, enabling conditional airfoil generation from an airfoil’s shape and structural feature definition.
Specifically, we demonstrate the application of Bidirectional Long Short Term Memory models and Bayesian Gaussian Mixture models to derive airfoil coordinates from a compact set of shape and structural characteristics that we define. The proposed framework is shown to achieve favorable airfoil performance optimisation due to improved exploration and exploitation of the design space, compared to traditional approaches. Overall, the proposed optimisation framework is able to realise a 9.04% performance improvement over an airfoil design optimised with traditional parameterisation techniques.CRediT authorship contribution statement
Vincent le Roux: Conceptualization, Methodology, Software, Validation, Formal analysis, Investigation, Writing– original draft, Writing review & editing, Visualization. Marelie H. Davel: Conceptualization, Methodology, Software, Validation, Formal analysis, Writing– original draft, Writing– review & editing, Supervision. Johan Bosman: Conceptualization, Methodology, Resources, Writing– original draft, Writing– review & editing, Supervision
How does the decision to cultivate underutilized crops influence food and nutrition security in rural areas?
Get PDFJournal Article, Faculty of Natural and Agricultural Science -- North-West University, Mahikeng CampusThe neglect in the cultivation, utilization, and diverse edible indigenous crops (ICs) threatens food-nutrition security (FNS) and rural development. Here, we (i) profiled the socioeconomics, ethnobotanicals and factors influencing the decision to cultivate edible ICs among smallholder farmers and (ii) factors influencing the FNS status of the ICs farmers in rural communities in South Africa using descriptive statistics and Heckman’s probit- selection model to evaluate the factors influencing the decision to cultivate ICs and FNS. In the study, the household dietary diversity score (HDDS) was 7.01 and the household’s food insecurity access scores (HFIAS) was 4.40. In addition, the food security indicator shows that 40.60 % of the participants were food insecure. Taken together, these metrics shows a significant existence of food and nutrition insecurity among the participants. Additionally, the decisions to cultivate ICs among the participants was driven by the household size, access to seeds, produce market, perceived nutritional benefits of the ICs and proportion of land used for cultivation significantly affects FNS status of the participants. Overall, the cultivation of these ICs is important as their cultivation significantly contributed to the FNS of the rural communities. Policy interventions, targeted at improving the present land tenure pattern, awareness on the value of ICs and incentives for production as a means for stimulating wider acceptance, cultivation, and sustainability in South Africa was recommended.Zero Hunge
Consumer objective and subjective knowledge about healthy foods: An approach to promote healthy lifestyle choices in South Africa
Get PDFJournal Article, Faculty of Health Sciences, Africa Unit for Transdisciplinary Health Research (AUTHER)-- Potchefstroom CampusUnhealthy food choices and consumption, coupled with sedentary lifestyles among consumers, intensify public health concerns regarding the quadruple disease burden, despite Primary Health Care (PHC) policy. However, the current relationship between consumer knowledge about healthy foods and following a healthy lifestyle needs to be explored. Our study, therefore, aimed to determine the association between consumers’ subjective and objective knowledge about healthy foods and various healthy lifestyle choices. A cross-sectional survey was conducted among employed consumers (N = 157) from South African corporate settings. We used structural equation modelling (SEM) to determine associations between subjective and objective knowledge about healthy foods and healthy lifestyle choices. Our findings showed that most participants scored high on making healthy lifestyle choices relating to avoiding smoking (69.5%) and limiting drinking alcohol (68.7%) but less so for food and sleep (44.4%) while neglecting exercise, relaxation (13.7%), and choices that require dedicated effort (25.2%). On average, participants had high levels of subjective (mean = 3.59; 5-point Likert scale) knowledge and objective knowledge about healthy foods (88.4−95.9% correct responses). However, their objective knowledge about weight and cholesterol had severe deficiencies (36.7%). SEM confirmed an association between subjective knowledge and most healthy lifestyle choice categories, while income contributed to dedicated effort lifestyle choices. By contrast, objective knowledge did not associate with such choices. Our structural model suggests that subjective knowledge about healthy foods contributes to healthy lifestyle choices. Therefore, subjective knowledge and the objective knowledge deficiencies we identified among corporate consumers can serve as a valuable starting point for informed education to promote PHC policy and healthy lifestyle choices.Funding: This research was funded by the National Research Foundation of South Africa (https://www.nrf.ac.za/, grant number: 87813) awarded to DvdM.“Any findings included in this material are the opinion of the authors and therefore, the NRF does not accept any liability in regard thereto”. The funders had no role in study design, data collection and analysis, the decision to publish, or the preparation of the manuscript
Distribution, abundance, population structures, and potential impacts of the invasive snail, Tarebia granifera in aquatic ecosystems of north-eastern South Africa
Get PDFJournal Article, Faculty of Natural and Agricultural Science, North--West University-PotchefstroomAquatic ecosystems globally have been invaded by molluscs. Tarebia granifera is ahighly successful invader, often becoming the dominant aquatic invertebrate speciesin an invaded ecosystem. Resultingly, it has been suggested that T. granifera may havesevere negative impacts on these invaded ecosystems. Limited information is avail-able regarding the population structures and densities of T. granifera, particularly ininvaded countries such as South Africa, and information on this could assist in devel-oping management and control strategies for this invasive species. The present studyaimed to assess the current distribution, densities, and population structures of T.granifera in invaded habitats on the Limpopo and Phongolo River systems in SouthAfrica. This was accomplished by collecting aquatic molluscs from sites across thesesystems. Water quality parameters were measured at each site and water sampleswere collected for chemical nutrient analyses. The density of snails was determinedfor each site and the population size and structure as well as birth rate was calculatedfor T. granifera. Tarebia granifera was found to be the dominant molluscan species inhabitats where it was present and all size classes from newborn to mature adultswere found throughout at some of the highest densities globally. Worryingly, nativemolluscan species, were often absent or in much lower densities than reported inliterature at sites where T. granifera was present, suggesting a negative effect on thenative molluscan density and diversity. Contrary to most previous studies, there wereno significant correlations between T. granifera and the selected water quality param-eters. Higher densities and newborn recruitment of T. granifera were observed in thespring than in autumn, likely in response to shifts in environmental conditions. Thisstudy provides crucial insights into the population structure, densities, and impacts ofT. granifera in invaded habitats, particularly for relatively newly invaded regions suchas southern Afric
Broadband multi-wavelength properties of M87 during the 2018 EHT campaign including a very high energy flaring episode
No full textArticle, Faculty of Natural and Agricultural Sciences (Centre for Space Research (CSR)--Northwest University, Potchefstroom CampusContext. The nearby elliptical galaxy M87 contains one of only two supermassive black holes whose emission surrounding the event horizon has been imaged by the Event Horizon Telescope (EHT). In 2018, more than two dozen multi-wavelength (MWL) facilities (from radio to γ-rayenergies) took part in the second M87 EHT campaign.
Aims. The goal of this extensive MWL campaign was to better understand the physics of the accreting black hole M87*, the relationship between the inflow and inner jets, and the high-energy particle acceleration. Understanding the complex astrophysics is also a necessary first step towards performing further tests of general relativity.
Methods. The MWL campaign took place in April 2018, overlapping with the EHT M87* observations. We present a new, contemporaneous spectral energy distribution (SED) ranging from radio to very high-energy (VHE) γ-rays as well as details of the individual observations and light curves. We also conducted phenomenological modelling to investigate the basic source propertiesesults. We present the first VHE γ-ray flare from M87 detected since 2010. The flux above 350 GeV more than doubled within a period of ≈36 hours. We find that the X-ray flux is enhanced by about a factor of two compared to 2017, while the radio and millimetre core fluxes are consistent between 2017 and 2018. We detect evidence for a monotonically increasing jet position angle that corresponds to variations in the bright spot of the EHT image.
Conclusions. Our results show the value of continued MWL monitoring together with precision imaging for addressing the origins of high-energy particle acceleration. While we cannot currently pinpoint the precise location where such acceleration takes place, the new VHE γ-ray flare already presents a challenge to simple one-zone leptonic emission model approaches, and it emphasises the need for combined image and spectral modelling
Analysis of forced convection in the HTTU experiment using numerical codes
Get PDFJournal Article, Unit for Energy and Technology Systems, North-West University, Potchefstroom CampusThe High Temperature Test Unit (HTTU) was an experimental set-up to conduct separate and integral effects tests of the Pebble Bed Modular Reactor (PBMR) core. The annular core consisted of a randomly packed bed of uniform spheres. Natural convection tests using both nitrogen and helium, and forced convection tests using nitrogen, were conducted. The maximum material temperature achieved during forced convection testing was 1200 °C. This paper presents the numerical analysis of the flow and temperature distribution for a forced convection test using 3D CFD as well as a 1D systems-CFD computer code. Several modelling approaches are possible, ranging from a fully explicit to a semi-implicit method that relies on correlations of their associated phenomena. For the comparison between codes, the analysis was performed using a porous media approach, where the conduction and radiative heat transfer were lumped together as an effective thermal conductivity and the convective heat transfer was correlated between the solid and gas phases. The results from both codes were validated against the experimental measurements. Favourable results were obtained, in particular by the systems-CFD code with minimal computational and time requirements
Draft genome sequence of Bacillus velezensis strains AOA1 and AKS2, the potential plant growth-promoting rhizobacteria
Get PDFJournal Article, Food Security and Safety Focus Area, Faculty of Natural and Agricultural Sciences, North-West University, Mafikeng CampusThis report describes the draft genome sequence of Bacillus velezensis strains AOA1 and AKS2 isolated from maize rhizosphere soil in South Africa. Bacillus velezensis plays important biological roles as plant growth promoting rhizobacterium (PGPR). Bacillus velezensis strains also exhibit numerous biotechnological application potentials in agriculture and diverse industrial settings
Being and Becoming a Teacher Educator in an Online Work-Integrated Learning Excursion for Future Super Teachers
Get PDFJournal Article.Research Unit Self-directed Learning, North-West University, Potchefstroom,This chapter reports on the professional development of novice teacher educators in an online work-integrated learning (WIL) excursion for future teachers. A self-study research design was used to explore how a novice teacher educator participating in an online WIL excursion, developed professionally through reflecting on their roles and experiences. A reflective journal, feedback from colleagues and participants, and video recordings were used to gather qualitative data, which were subsequently thematically coded in order to find key patterns and themes. The findings indicated both strengths and areas for improvement in the novice teacher educator’s social, communication, and technological roles in the online educational setting. The implications for further research underscore the importance of integrating peer feedback, reflective practices, and qualitative methodologies to support the development of novice teacher educators in online educational settings
A review of the reported and future potential ecological impacts of the invasive freshwater snail Tarebia granifera in South Africa.
Get PDFJournal Article, Unit for Environmental Sciences and Management, North-West University, Potchefstroom CampusThe Southeast Asian gastropod Tarebia granifera is an invasive freshwater snail across several continents. Our review summarises the impacts of this invasive snail on invaded aquatic ecosystems. The most important impacts are those related to their ability to reproduce quickly and reach high densities within invaded ecosystems. The snail has reportedly caused declines and local extinctions in native snail populations globally. They can further significantly reduce algal standing stocks and may have severe impacts on benthic biomass, resulting in decreased benthic biodiversity and disturbances in aquatic ecosystem function. These invasive snails also cause bioturbation that can lead to changes in the nutrient cycles of invaded aquatic ecosystems and affect food web dynamics, with unknown implications for ecosystem function. Furthermore, T. granifera is well known to harbour a diverse range of parasitic species of medical and veterinary importance both within and outside their native ranges. The effective control of invasive T. granifera remains challenging as they are not easily preyed upon, and potential control methods may have unintentional side effects on native biota. This review provides evidence that there is a need to control this invader to avoid further degradation of freshwater habitats and aquatic biodiversity
Social life cycle assessment of the olive oil industry: a case study in Guilan Province, Iran
Get PDFArticle, Faculty of Economic and Management Sciences (Workwell: Research Unit for Economic; Management Sciences)--Northwest University, Potchefstroom CampusOlive oil production has severe environmental consequences, including resource depletion, land degradation, carbon emissions, and waste generation. As a result, for over two decades, environmental life cycle assessment (ELCA) has been applied to the olive oil industry to identify environmental issues and reduce the environmental effects. However, little is known regarding the social sustainability of this industry. Social life cycle assessment (S-LCA) has been established as one of the most effective methodologies for assessing the social implications of products throughout their life cycles. Accordingly, based on the S-LCA approach, this study aims to assess the social impacts of the olive oil extraction industry in Roudbar County in Guilan Province in Iran, the major producer of olives and olive oil. The S-LCA model adopted in this paper is built in four major phases (UNEP/ SETAC in Guidelines for social life cycle assessment of products, 2009): (1) Definition of Goal and Scope: outlines the intended use and the goal pursued and specifies the scope of the research. The research will then be defined to fulfill that purpose within any con- straints. (2) Life Cycle Inventory analysis: is the phase at which data are collected, systems are modeled, and LCI results are generated. (3) Life Cycle Impact Assessment: a collection of steps to obtain data categorization, aggregation, and characterization based on performance reference points. (4) Life Cycle Interpretation: considers all important aspects of the research when drawing results, offering recommendations, and reporting. The findings suggested that the social conditions governing the olive oil extraction cycle in the study area are almost adequate. However, other categories of social impacts, such as cultural heritage, community development, and working conditions, were rated unsatisfactory by olive orchard workers and need improvement. Adopting the cause-and-effect chain in this study favors identifying specific indicators based on social issues in the study location. On the other hand, a scale-based assessment may result in the subjectivity of the results, which adds to the uncertainty. An impact-based assessment may be applied to analyze social impacts such as occupational health and safety, employment, pay, and benefits to get more credible social impact data. Consequently, integrating the scale-based approach with an efficient path-based method may improve its effectiveness