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FPGA accelerated radio galaxy classification with a Fourier convolutional neural network
Get PDFEdwards, B. J. 2025. FPGA Accelerated Radio Galaxy Classification
with a Fourier Convolutional Neural Network. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/0f7df7f9-5856-46d0-819c-c7f9bf4f8335Thesis (MEng)--Stellenbosch University, 2025.ENGLISH ABSTRACT: Morphological classification of observed radio sources has become fundamental in studies related to galaxy formation and evolution. It is therefore important to modern astronomy as a whole. Recently, Convolutional Neural Networks (CNNs) have enabled researchers to implement network architectures that are able to classify radio galaxies with high accuracies. However, the spatial convolutions in these networks are computationally expensive. This project aims to replace the spatial convolutions in a CNN with elementwise multiplications in the frequency domain to reduce computational complexity. We then investigate speeding up inference and reducing hardware power consumption through the use of an Alveo U280 Field Programmable Gate Array (FPGA) accelerator card. We developed a frequency domain CNN capable of morphological galaxy classification. Our proposed model requires fewer computations for classification than tested radio galaxy CNN architectures with a similar number of trainable parameters. However, we found that this computational reduction comes at the cost of a lower accuracy. We were able to speed up inference and improve the power efficiency of our proposed model with the FPGA accelerator card compared to a Central Processing Unit (CPU)-only implementation of the model.AFRIKAANSE OPSOMMING: Die morfologiese klassifisering v a n r a diobronne het fundamenteel geword in studies rakende die vorming en evolusie van sterrestelsels. Dit is dus belangrik vir moderne sterrekunde as geheel. Die onlangse verwikkelinge in konvolusionele neurale netwerke (KNNe) stel navorsers in staat om radio-sterrestelsels met hoë akkuraatheid te kan klassifiseer. Die konvolusies in hierdie netwerke is egter berekening-intensief. Hierdie projek beoog om die spasiële konvolusies in sogenaamde netwerke te vervang met elementgewys vermenigvuldigings in die frekwensiedomein sodat die totale hoeveelheid bewerkings wat nodig is vir klassifisering v erminder k an w o rd. S aam hi ermee b eoog di e projek o m di e sp oed van klassifisering te verhoog en die energieverbruik daarvan te verminder deur die gebruik van ‘n Alveo U280 FPGA-versnellingskaart. Ons het ‘n frekwensiedomein-KNN ontwikkel wat in staat is tot morfologiese klassifikasie van radio-sterrestelsels. Die voorgestelde model vereis minder berekeninge vir klassifisering teenoor getoetsde radio-sterrestelsel-KNN-argitekture met soortgelyke opleibare parameters. Ons het egter gevind dat die vermindering in berekeninge ten koste van ‘n laer akkuraatheid kom. Met die gebruik van die FPGA-versnellingskaart kon ons die spoed van klassifisering e n d ie k ragdoeltreffendheid va n di e vo orgestelde model ve rbeter in vergelyking met ‘n sentrale verwerkingseenheid (SVE)-implementering van die model.Master
Recombinant protein expression in Komagataella pastoris and the scheduling of a multistage, multiproduct facility producing alternative sweeteners from A-molasses
Get PDFMamba, P. E. 2025. Recombinant protein expression in Komagataella pastoris and the scheduling of a multistage, multiproduct facility producing alternative sweeteners from A-molasses. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/111d8af1-ea00-44b1-add4-d5ea3af09b44Thesis (MEng)--Stellenbosch University, 2025.ENGLISH ABSTRACT: The South African Sugar Industry (SASI) is financially distressed due to challenges such as subsided sugar prices in the global markets, increasing energy costs, and decreasing local sugar demand. The latter leaves the SASI with surplus sugar that is then exported to distorted global markets at discounted prices, resulting in revenue losses. Diversifying the product range of the SASI by co-producing bioproducts such as low-calorie sweeteners and commodity chemicals such lactic acid has gained traction as viable options to help revitalise the SASI. The low-calorie content and the generally regarded as safe (GRAS) status of alternative sweeteners such as allulose, short-chain fructooligosaccharides (scFOS), isomaltulose, and thaumatin have made them potential replacements for sucrose in food and beverages. A-molasses, an intermediate stream in sugar manufacturing has been identified as a potential feedstock for co-producing these sweeteners. The aim of this study was to recombinantly express thaumatin and D-psicose 3-epimerase (DPEase) enzyme used in allulose production in Komagataella pastoris, and design a multistage, multiproduct facility producing thaumatin, allulose, scFOS, and isomaltulose from A-molasses. This was followed by the economic viability assessment of the designed facility. A β-fructofuranosidase (FFase) enzyme-producing strain of K. pastoris was cultivated in an A-molasses derived fermentation medium to empirically elucidate the potential use of A-molasses in such applications. Herein, the FFase enzyme was used as a reporter protein. Biomass titres of 136.4 gdcw/L and 137.9 gdcw/L were achieved from strains transformed with the native and codon-optimised thaumatin gene, respectively. Despite the successful growth resulting in high biomass, there was no evidence of recombinant thaumatin in the culture supernatants of both strains. Therefore, the strains were concluded to be incompetent in expressing recombinant thaumatin. Biomass titres of 137.7 gDCW/L were obtained from the K. pastoris strain expressing recombinant DPE enzyme under the GAP promoter. The DPE enzyme was successfully expressed but it was inactive and incompetent in converting D-fructose to D-allulose. Biomass titres of 125.05 gDCW/L were achieved when the K. pastoris strain expressing FFase enzyme was cultured in hydrolysed A-molasses medium. The highest FFase enzyme activity of 1784 U/ml was obtained after 55 hrs of fermentation. The satisfactory biomass titre and enzyme activity indicated A-molasses' ability to replace synthetic medium such as BSM with minimal effects on biomass and protein titres. Moreover, A-molasses cultures showed lower oxygen demand compared to BSM cultures of the same strain. The inability to express thaumatin and functional DPE enzyme created limitations and uncertainty for the scheduling model and techno-economic analysis. Experimental values of the protein titre and enzyme activity were intended for use as model input data but were replaced with literature values considering the experimental challenges. Following a mixed product campaign (MPC), the equipment sizing, batching, and scheduling of a multistage, multiproduct facility producing four sweeteners from A-molasses were successful. The developed schedule executed all the required batches within the stipulated time horizon of 5000 hours. The determined equipment sizes were deemed acceptable and were within design limits, with the highest processing rate of 60.1 tons/hr obtained for the simulated moving bed chromatography. Deterministic techno-economic analysis using an internal discount rate of 20% yielded an internal rate of return (IRR) of 52% with a payback period of 3.08 years. The high IRR obtained indicated that the multiproduct facility is economically profitable.AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar.Master
Ionizing radiation sensor unit for nanosatellite applications
No full textThomas, Kelsey Jayde. 2025. Ionizing radiation sensor unit for nanosatellite applications. Unpublished master's thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/handle/10019.1/131934Thesis (MEng)--Stellenbosch University, 2025.ENGLISH ABSTRACT: This thesis details the development of an ionizing radiation sensor unit for nanosatellite applications. The design utilises Commercial-Off-The-Shelf (COTS) components to measure fluence and Total Ionizing Dose (TID). The CY62157EV30LL-45ZXI Static Random Access Memory (SRAM) is selected as the fluence sensor and the IRF9510 Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) for the TID sensor. The design of the sensor unit and the experimental setups were optimised through simulations and testing. TID testing was conducted using a Cobalt-60 source at Agricultural Research Council (ARC). The SRAM underwent Single Event Effects (SEE) testing using 27 MeV to 56 MeV protons at iThemba Laboratories for Accelerator Based Science (LABS). The SRAM was characterised through detailed analysis of the radiation-induced errors, finding a maximum cross-section of 1.65E-11 cm2/bit. The MOSFET showed a linear response to increasing total dose. Additionally, the sensor unit includes system health monitoring capabilities. This research demonstrates the feasibility of using COTS components as effective ionizing radiation sensors for space applications.AFRIKAANSE OPSOMMING: Hierdie tesis beskryf die ontwikkeling van ’n ioniserende straling sensor eenheid vir nanosatellite toepassings. Die ontwerp gebruik Kommersie¨el-van-die-Rak-Komponente (KARK) (Eng: Commercial-Off-The-Shelf (COTS)) om vloed en Totale Ioniserende Dosis (Eng: TID) te meet. Die CY62157EV30LL-45ZXI SRAM word gekies as die vloed sensor en die IRF9510 MOSFET vir die TID-sensor. Die ontwerp van die sensoreenheid en die eksperimentele opstellings is geoptimeer deur simulasies en toetsing. TID-toetsing is uitgevoer met behulp van ’n Cobalt-60-bron by die Agricultural Research Council (ARC). Die SRAM het Enkel Gebeurtenis Effek (EGE) (Eng: SEE)toetsing ondergaan deur 27 MeV tot 56 MeV-protone by iThemba LABS te gebruik. Die SRAM is gekenmerk deur gedetailleerde ontleding van die straling-ge¨ınduseerde foute, wat ’n maksimum deursnee van 1.65E-11 cm2/bit gevind het. Die MOSFET het ’n lineˆere reaksie op toenemende totale dosis getoon. Addisioneel bevat die sensor-eenheid stelsel gesondheid moniterings vermo¨ens. Hierdie navorsing demonstreer die uitvoerbaarheid van die gebruik van COTS-komponente as effektiewe ioniserende stralingsensors vir ruimte toepassings.Master
Sustainable methanol production from blast furnace gas: comparing carbon capture techniques and optimizing hydrogen integration
Get PDFMakakavhule, N. 2025. Sustainable methanol production from blast furnace gas: comparing carbon capture techniques and optimizing hydrogen integration. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/195a5c6e-0970-4305-9919-00b557928b9bThesis (MEng)--Stellenbosch University, 2025.ENGLISH ABSTRACT: The synthesis of low-carbon methanol from CO₂ and H₂ was examined using two carbon capture processes, amine absorption with methyldiethanolamine (MDEA) and Vacuum Pressure Swing Adsorption (VPSA), both enhanced by a Water Gas Shift (WGS) reactor. This novel study focused on capturing CO₂ from Blast Furnace Gas (BFG) in the iron and steel industry for methanol production through CO₂ hydrogenation comparing the two carbon capture processes with heat integration. Methanol holds significance beyond its role as a chemical feedstock, emerging as an attractive alternative fuel due to its ease of storage and diverse applications in fuel and chemical processes. As a versatile, globally traded chemical, it serves as a vital feedstock for the chemical industry and as an energy carrier, contributing to products such as paints, textiles, solvents, and plastics. Industry projections indicate substantial growth in methanol demand by 2050, driven by advancements in petrochemical technologies, including methanol-to-olefins (MTO), methanol-to-gasoline (MTG), and methanol-to-propylene (MTP). Additionally, renewable methanol production using green hydrogen and captured CO₂ is expected to play a significant role in meeting future demand. This research evaluated three methanol production capacities for both the amine and VPSA carbon capture plants by adjusting the BFG feed rates: 148 kg/s (capacity 1), 29.5 kg/s (capacity 2), and 5.91 kg/s (capacity 3). The amine plant achieved methanol outputs of 261 kt/a, 52 kt/a, and 10 kt/a, while the VPSA plant produced 275 kt/a, 55 kt/a, and 11 kt/a. Analysis of key plant parameters revealed significant variations in energy efficiency between the two systems. The VPSA system was significantly more energy efficient, requiring approximately 88% less energy for the storage and utilization of 1 kg of captured CO2 and the production of 1 ton of methanol, using only 12% of the energy consumed by the amine plant. For the regeneration duty, the amine plant required 41% more energy per ton of BFG, due to the thermal intensive solvent regeneration in the stripper reboiler, while the VPSA system used only 59% of this energy. The WGS steam requirement to produce 1 kg of methanol was 5% higher in the amine plant, with the VPSA plant consuming only 95% of the steam required by the amine system. Conversely, the VPSA plant exhibited a 22% higher electricity demand per ton of methanol, driven by the continuous operation of vacuum pumps, meaning the amine plant used 78% of the electricity required by the VPSA system. These results highlight the trade-offs between the two systems, with the VPSA system offering superior energy efficiency in most aspects, despite its higher electricity consumption. Heat integration analysis demonstrated significant improvements in thermal efficiency for both systems. The efficiency for the amine-based process increased from approximately 30% to 50% after heat integration, while for the VPSA systems a smaller improvement from approximately 45% to 55% was observed. The amine system's larger efficiency gains were attributed to its complex heat exchange network and higher energy demands for solvent regeneration, creating additional heat integration opportunities. Economic analysis through carbon tax and credit calculations revealed that plants with carbon capture technology are more economically viable than those without. At maximum capacity, the amine process generated annual carbon credits of R4.08 billion, resulting in a net gain of R4.00 billion after carbon deductions. The VPSA plant produced R3.92 billion in annual carbon credits, with a net gain of R3.84 billion, showing slightly lower profitability (4% less) compared to the amine plant. The study demonstrated clear economies of scale, with larger plant capacities yielding significantly higher annual net impacts. The highest capacity configuration (148 kg/s of BFG) showed the potential to generate approximately five times more profit than the medium capacity and twenty-five times more than the lowest capacity, highlighting the economic advantages of larger scale operations. This profitability was primarily driven by carbon credits earned from storing and utilizing the captured CO₂ rather than emitting it.AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar.Master
Use of naturally durable wood as an alternative to the use of chemical-based wood preservation
Get PDFThesis (MScFor)--Stellenbosch University, 2025.Jayeola, V. A. 2025. Use of Naturally Durable Wood as an Alternative to the
use of Chemical-based Wood Preservation. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/1a04c628-4c1e-48af-b258-90635dc3519cENGLISH ABSTRACT: Environmental and health concerns surrounding the use of chemical wood preservatives such as chromated copper arsenate (CCA), creosote, pentachlorophenol, among others have led to an urgent search for sustainable alternatives. These preservatives, while effective in protecting wood from decay, pose risks of soil and water contamination, and potential carcinogenic effects on humans.
Naturally durable woods have inherent ability to resist attacks from fungi, insects, bacteria, and marine borers. Among the naturally durable species, Eucalyptus species presents unique characteristics such as, fast-growth, and ability to produce significant amount of heartwood (responsible for wood durability) in a short period. This study then focused on evaluating the performance of some Eucalyptus species in a two-year in-ground degradation trial compared to chemically treated and untreated wood. The objectives were: (a) to evaluate degradation performance after exposure based on applicable standards (b) to characterise wood to develop an understanding of the inherent properties that influence performance.
A two-year field trial was conducted to assess the in-ground durability of Eucalyptus cladocalyx and Eucalyptus cloeziana compared to chemically treated Pinus radiata wood. Performance was assessed using visual assessment, mass loss measurement, and follow up methods such as density using computed tomography scan (CT scan), scanning electron microscopy SEM, and chemical analysis to provide insights into structural changes and durability mechanisms.
Eucalyptus cladocalyx wooden stakes (samples) showed slight to moderate decay, with edge regions of the stakes typically rated as slightly decayed (1) and pith regions rated as moderately decayed (2). Statistical analysis indicated no significant difference in decay ratings between these regions, suggesting uniformity in structural properties. In contrast, Eucalyptus cloeziana exhibited consistent moderate decay (rating 2) across the edge and pith regions. CCA-treated Pinus radiata stakes were consistently used as controls receiving a decay rating of 0 (no attack).
The mass loss in Eucalyptus cladocalyx stakes ranged from 6.05% (edge) to 12.81% (pith), which was higher than the 2.85% observed in CCA-treated Pinus radiata, though no significant difference was found (p = 1). Eucalyptus cloeziana demonstrated the highest mass losses, with mean values of 34.07% (edge) and 32.51% (pith), significantly different from E. cladocalyx and CCA-treated Pinus radiata (p < 0.05).
For the follow-up tests, a consistent density decrease was observed from below the groundline (604.2 kg/m³) to the groundline (546.3 kg/m³) for E. cloeziana. In contrast, E. cladocalyx showed no clear density trend, with the highest mean density of 1032.1 kg/m³ at the lower middle position, indicating enhanced durability. The fungal presence within the vessels of E. cloeziana was also notably higher, with fungal hyphae detected in the pith region, while the edge region of E. cladocalyx showed no visible fungal presence.
Chemical analysis on E. cloeziana revealed changes in wood composition. The reference sample had the highest cellulose content (30.1%), while degraded samples showed a reduction in cellulose and an increase in hemicellulose, extractives, and lignin, particularly in the pith and edge regions. This suggests that cellulose breakdown contributed to the degradation process.
These findings reveal that E. cloeziana wood is not suitable for in-ground applications. Eucalyptus cladocalyx on the other hand, shows the potential as a sustainable, non-toxic alternative to chemical wood treatments. Its rapid growth and natural durability make it suitable for agricultural uses, such as vineyard poles, reducing reliance on harmful preservatives. This aligns with South Africa’s bio-economy strategy and global sustainability objectives.AFRIKAANSE OPSOMMING: Omgewings- en gesondheidsorg rondom die gebruik van chemiese houtpreserveermiddels soos
gechromeerde koperarsenaat (CCA), kreosoot, pentachloorfenol, onder andere, het gelei tot 'n
dringende soeke na volhoubare alternatiewe. Hierdie preserveermiddels, terwyl dit effektief is om
hout teen verval te beskerm, hou risiko's in van grond- en waterbesoedeling, en potensiële
karsinogene
effekte op mense.
Natuurlik duursame houtsoorte het 'n inherente vermoë om aanvalle van swamme, insekte, bakterieë en
seeboorders te weerstaan. Onder die natuurlik duursame spesies bied Eucalyptus spesies unieke
eienskappe soos vinnige groei en vermoë om aansienlike hoeveelheid kernhout
(verantwoordelik vir hout duursaamheid) in 'n kort tydperk te produseer. Hierdie studie het toe
gefokus op die evaluering van die prestasie van sommige Eucalyptus spesies in 'n twee-jaar in-grond
degradasie proef in vergelyking met chemies behandelde en onbehandelde hout. Die doelwitte was: (a)
om afbraakprestasie na blootstelling te evalueer gebaseer op toepaslike standaarde (b) om hout te
karakteriseer om 'n begrip te ontwikkel van die inherente eienskappe wat prestasie beïnvloed.
'n Twee jaar veldproef is uitgevoer om die in-grond duursaamheid van Eucalyptus cladocalyx en
Eucalyptus cloeziana te bepaal in vergelyking met chemies behandelde Pinus radiata hout. Prestasie
is geassesseer deur gebruik te maak van visuele assessering, massaverliesmeting en opvolgmetodes
soos digtheid deur gebruik te maak van rekenaartomografieskandering (CT-skandering),
skandeerelektronmikroskopie SEM en chemiese analise om insigte in strukturele veranderinge en
duursaamheidsmeganismes te verskaf.
Eucalyptus cladocalyx houtpale (monsters) het effense tot matige verval getoon, met randstreke van
die pale wat tipies as effens verval (1) gegradeer is en mergstreke as matig verval (2).
Statistiese analise het geen betekenisvolle verskil in vervalgraderings tussen hierdie streke
getoon nie, wat dui op eenvormigheid in strukturele eienskappe. In teenstelling hiermee het
Eucalyptus cloeziana konsekwente matige verval (gradering 2) oor die rand- en pitstreke getoon.
CCA-behandelde Pinus radiata-stake is konsekwent gebruik as kontroles wat 'n vervalgradering van 0
(geen aanval) ontvang
het nie.
Die massaverlies in Eucalyptus cladocalyx-stake het gewissel van 6.05% (rand) tot 12.81% (pit), wat
hoër was as die 2.85% wat in CCA-behandelde Pinus radiata waargeneem is, alhoewel geen
betekenisvolle verskil gevind is nie (p = 1). Eucalyptus cloeziana het die hoogste massaverliese
getoon, met gemiddelde waardes van 34.07% (rand) en 32.51% (pit), betekenisvol verskillend van E.
cladocalyx en CCA-behandelde Pinus radiata (p < 0.05).
Vir die opvolgtoetse is 'n konsekwente afname in digtheid waargeneem vanaf onder die grondlyn
(604.2 kg/m³) na die grondlyn (546.3 kg/m³) vir E. cloeziana. Daarteenoor het E. cladocalyx geen
duidelike digtheidstendens getoon nie, met die hoogste gemiddelde digtheid van 1032.1 kg/m³ by die
laer middelste posisie, wat verbeterde duursaamheid aandui. Die swam teenwoordigheid binne die
vate van E. cloeziana was ook noemenswaardig hoër, met swamhifes wat in die merggebied opgespoor
is, terwyl die randgebied van E. cladocalyx geen sigbare swam teenwoordigheid getoon het nie.
Chemiese ontleding op E. cloeziana het veranderinge in houtsamestelling aan die lig gebring. Die
verwysingsmonster het die hoogste sellulose-inhoud (30.1%) gehad, terwyl afgebreekte monsters 'n
vermindering in sellulose en 'n toename in hemisellulose, ekstrakteermiddels en lignien getoon het,
veral in die merg- en randgebiede. Dit dui daarop dat sellulose-afbraak bygedra het tot die
afbraakproses.
Hierdie bevindinge toon dat E. cloeziana-hout nie geskik is vir in-grond toedienings nie.
Eucalyptus cladocalyx aan die ander kant, toon die potensiaal as 'n volhoubare, nie-giftige
alternatief vir chemiese houtbehandelings. Sy vinnige groei en natuurlike duursaamheid maak dit
geskik vir landbougebruike, soos wingerdpale, wat die afhanklikheid van skadelike preserveermiddels
verminder.
Dit strook met Suid-Afrika se bio-ekonomiestrategie en globale volhoubaarheidsdoelwitte.Master
Design, build and test of a novel X-shaped, tilt-wing quadcopter
Get PDFvan Deventer, D. 2025. Design, build and test of a novel X-shaped, tilt-wing quadcopter. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/20324f4d-107a-46b0-8f03-6b6e8b989207Thesis (MEng)--Stellenbosch University, 2025.ENGLISH ABSTRACT: Unmanned aerial vehicles, specifically quadcopters, have become integral to various industries. They are especially sought after for their ease of control, stability and practicality. Quadcopters can complete tasks while the operator remains safely grounded. The largest drawback of quadcopters is their inefficient nature and the consequential flight time and range. Although different configurations of quadcopters have been researched in recent years, many configurations remain unexplored. To combat the inefficiency of quadcopters, a novel configuration is proposed to increase flight time and distance while maintaining the desirable features. The configuration will enable all actuators and lift-generating surfaces to be utilised optimally, whether the quadcopter hovers or travels forward. The actuators and propellers were chosen to be optimal for the desired weight of the quadcopter without the added weight of the drivetrain and wings. A hybrid analytical-numerical model was then developed to evaluate the performance of the configuration in different flight modes. This ensures that adding extra components is beneficial even when the propulsion system is not optimised for the specific configuration. A custom frame, printed circuit board, wings, and drivetrain were designed and assembled. A novel control method and switching strategy were also developed to ensure that control is possible in the configuration. Multiple flight tests were conducted to tune the control system of the quadcopter and to ensure that it can transition reliably between the flight modes. The power draw data of the quadcopter was obtained with and without the addition of the extra components and then compared. The value of the research lies in the fact that this simplistic design and conceptual premise delivers an increase in efficiency whilst maintaining the desirable features of quadcopters, yet it has been overlooked until now. The novel configuration could inspire other configurations and, therefore, further advancements in quadcopter technology.AFRIKAANSE OPSOMMING: Onbemande vliegtuie, en meer spesifiek hommeltuie, het ’n integrale deel van verskeie industrieë geword. Hulle is veral gesog vir hul gemak van beheer, stabiliteit en praktiese gebruik. Hommeltuie kan take voltooi terwyl die operateur veilig op die grond bly. Die grootste nadeel van hommeltuie is hul ondoeltreffende aard en die gevolglike vlugtyd en vlugafstand wat direk benadeel word. Alhoewel verskillende konfigurasies van hommeltuie in onlangse jare nagevors is, is daar steeds baie konfigurasies wat onontgin bly. Om die ondoeltreffendheid van hommeltuie te bekamp, word ’n nuwe konfigurasie voorgestel met die doel om vlugtyd en vlugafstand te verhoog, terwyl die gewenste kenmerke behou word. Die konfigurasie sal dit moontlik maak om alle aktueerders en vlieggenererende oppervlaktes optimaal te benut, of die hommeltuig hang aldan vorentoe beweeg. Die aandrywers en skroewe is gekies om optimaal te wees vir die gewenste gewig van die hommeltuig sonder die bykomende gewig van die dryfstelsel en vlerke. ’n Hibriede analities-numeriese model is ontwikkel om die werkverrigting van die konfigurasie in verskillende vlugmodusse te evalueer. Dit verseker dat die byvoeging van addisionele komponente voordelig is selfs wanneer die aandrywingstelsel nie vir die spesifieke konfigurasie geoptimaliseer is nie. ’n Pasgemaakte raam, gedrukte stroombaan, pasgemaakte vlerke en pasgemaakte dryfstelsel is uniek ontwerp en saamgestel. ’n Nuwe beheermetode en skakelstrategie is ook ontwikkel om te verseker dat beheer in die ontwerp moontlik is. Veelvuldige vlugtoetse is uitgevoer om die beheerstelsel van die hommeltuig in te stel en om te verseker dat dit betroubaar tussen die vlugmodusse kan oorskakel. Die kraggebruik data van die hommeltuig is verkry met en sonder die byvoeging van die addisionele komponente en dan vergelyk. Die waarde van die navorsing lê daarin dat hierdie simplistiese ontwerp en konseptuele uitgangspunt ’n toename in doeltreffendheid lewer, terwyl die gewenste kenmerke van hommeltuie behoue bly, maar dit is tot nou toe oor die hoof gesien. Die nuwe konfigurasie kan ander konfigurasies beïnvloed en dien as inspirasie tot verdere vooruitgang in hommeltuig-tegnologie.Master
Conceptual modelling of microplastic fragmentation in the marine environment
Get PDFHenri, J. T. 2025. Conceptual modelling of microplastic fragmentation in the marine environment. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/22027e8e-3a00-45b1-b9f1-d68cc7a0abf2Thesis (MEng)--Stellenbosch University, 2025.ENGLISH ABSTRACT: Under the overarching context of the formation, fate, and transport of microplastic in the marine environment, the primary aim within the scope of this project was to develop a conceptual mathematical model describing plastic degradation within the marine ecosystem. The first objective of this study was to investigate the various degradation routes for plastic and the relationship between photo-oxidation and mechanical breakage. The second objective was to compare plastic degradation (due to photo-oxidation followed by mechanical breakage) rates in various environments such as urban areas, simulated by ceramic abrasion; beach environments, simulated by fine particulate sand abrasion; and ocean surf environments, simulated by wet sand abrasion in a rotating vessel. The third objective was to develop a conceptual mathematical model for the photo-oxidation mechanical degradation pathway. The fourth objective was to fit model parameters to experimental data through mathematical back-calculation techniques. The objectives of this study have been achieved by firstly studying plastic degradation mechanisms; secondly, designing a two-factor experiment to study the combined effect of photo-oxidative and mechanical abrasion upon plastic degradation characteristics; and thirdly, carrying out batch abrasion-fragmentation experiments to obtain microplastic breakage data to investigate the extent to which prior exposure of plastic particles to ultraviolet radiation affected its breakage characteristics. Fourthly, with experimental data generated, models were developed which fit the associated parameters and describe the breakage characteristics. To achieve the objectives stated, an ultraviolet radiation chamber was built with a capacity of 1000 g plastic and irradiation intensity of 1000 W/m2. Pretreatment of the plastic for abrasive fragmentation studies was carried out in the irradiation chamber, where accelerated photo-oxidative degradation mechanisms were induced for durations of 72 − 192 hr to understand breakage processes and rates of a plastic particle starting size class of 2800−4000 μm. A rotary abrasion vessel (D = 200 mm; L = 270 mm) was designed to be operated between 66 − 75 rpm on rollers driven by an electric motor. Thereafter, three different environmental attrition-fragmentation conditions were investigated in the rotary abrasion vessel with incrementing time intervals. Plastic mechanical fragmentation on pathways, rocks, and pebbles was approximated by investigating the breakage of particles when using ceramic milling media in the mill. Thereafter, finer fragmentation plastic experiences on the shoreline were simulated in the rotating vessel with sand as abrasion media. Finally, an abrasive environment in the surf was simulated in the rotating vessel causing the rupture of brittle plastic particles colliding with sand particles in the water and sand mixture. Analytical, average, and differential model solutions were developed for simulation conditions in the coastal environment. First-order differential equations were parameterised to model the breakage of the plastic and microplastic formation with respect to abrasion time. A key finding was the onset of plastic brittleness that occurred at an ultraviolet treatment time of approximately 70 hr, leading to mass loss in all the simulated environments. In the ceramic environment, with ultraviolet exposure times of 120 hr, it was found that polypropylene pellets in size class 2800−4000 μm loses 80 % of its mass to lower size classes within 32 min of abrasion, resulting in 74.4 % of particles reporting to the 2350−2800 μm size class and the balance to size class 0−2350 μm. Thus, mass loss from 2350−4000 μm size class is 5.6 %. Concatenation of sieve sizes into lower 0−1700 μm and upper 1700−4000 μm classes revealed a mass loss of 5.96 % within 32 min and 8.75 % in 136 min. Mathematical modelling yields selection function S = 0.1857ln(tnUV) + 0.1756. In comparison, similar plastic particles with a UV-T of 120 hr degraded with a 8.36 % mass loss after 72 hr of abrasion in the sand environment in repeatability tests. Analysis yields a selection function S = 0.0023ln(tnUV) + 0.0026. While in the sand and water environment, plastic loses 14 % of its mass after 120 hr of ultraviolet treatment and 120 hr of abrasion in a sand and water abrasion environment under the irradiative-abrasive conditions simulated. Analysis yields a selection function S=0.001ln(tnUV)+0.0015.AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar.Master
Integrating Satellite-Tracking in Wildlife Conservation: A Review and Proposal
Get PDFStrydom, Q. A. 2025. Integrating Satellite-Tracking in Wildlife Conservation: A Review and Proposal. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/25244fab-a7ab-44b5-ae00-7c8a97af3c4fThesis (MEng)--Stellenbosch University, 2025.ENGLISH ABSTRACT: Significant effort is invested into the understanding the environmental factors influencing wild animal behaviour and movement. This knowledge aids in addressing animal-human conflicts, controlling animal-borne diseases, preventing poaching, and fulfilling scientific inquiry. Terrestrial communication networks, limited by coverage and costly infrastructure, are often expensive and difficult to maintain in remote areas. With reduced costs and wide coverage, Direct-to Satellite IoT (DtS IoT) communication offers a promising alternative. This thesis explores integrating satellite communication into a wildlife monitoring sensor network aimed at conservation. The study utilizes the Argos satellite constellation, comprising nine active Low Earth Orbit (LEO) satellites dedicated to global environmental data collection. The Argos system’s coverage was evaluated with transmitters deployed in areas with varying horizon profiles, revealing that terrain significantly affects transmission success, with elevated horizons reducing satellite visibility. The highest success rates occur with satellites above 20° elevation, yet more than half the satellite passes are below 10°. Since the Argos satellite system currently only support uplink for IoT platforms, and the satellites are not continuously in line of sight closer to the equator, it is necessary to investigate a transmission strategy to improve communication success. A transmission strategy is proposed and simulated to gauge performance relating to success rate, time to delivery and power usage. Through simulations, the proposed strategy was found to improve the likelihood of transmitting while a satellite is in view by 20%. Furthermore, the proportion of transmissions occurring with satellites above 20° elevation can more than double. A transmission strategy was proposed to address the Argos system’s uplink-only limitation and inconsistent visibility, especially near the equator. Through simulations, the proposed strategy was found to improve the likelihood of transmitting while a satellite is in view by 20%. Furthermore, the proportion of transmissions occurring with satellites above 20° elevation can more than double. Other aspects, such as time to delivery and power usage is also analysed. It was seen that increasing the transmission power from 250mW to 1000mW does not significantly influence the transmission success, and neither does it significantly impact on the battery life since the short transmission bursts happen very infrequent. Overall, this thesis contributes to satellite-enabled conservation technology, offering practical insights into transmitter performance in varying conditions and proposing enhanced transmission strategies for improved resource management.AFRIKAANSE OPSOMMING: Aansienlike moeite word gedoen om die omgewingsfaktore wat wilde diere se gedrag en beweging be¨ınvloed te verstaan. Hierdie kennis help met aanspreking van dier-menskonflikte, die beheer van diere-oordraagbare-siektes, die voorkoming van stropery en die vervulling van wetenskaplike nuuskierigheid. Terrestri¨ele kommunikasienetwerke is beperk deur dekking en is dikwels duur en moeilik om in afgele¨e gebiede in stand te hou. Met verminderde koste en wye dekking bied Direk-na-Satelliet Internet van Dinge (DtS IoT) kommunikasie ’n belowende alternatief. Hierdie tesis ondersoek die integrasie van satellietkommunikasie in ’n wildmonitering-sensornetwerk gemik op natuurbewaring. Die studie maak gebruik van die Argos-satellietkonstellasie, ’n globale omgewingsdatainsamelings netwerk wat bestaan uit nege Laag Aarde Wentelbaan (LEO)-satelliete. Die Argos-stelsel se dekking is ge¨evalueer deur om senders te ontplooi in gebiede met wisselende horisonprofiele. Die bevindinge in hierdie tesis dui aan dat die transmissiesukseskoers wesenlik deur die terreinprofiel be¨ınvloed word, waar verhoogde horisonne wat satellietsigbaarheid verminder. Dwarsdeur die studie word die hoogste sukseskoers waargeneem wanneer satelliete bo ’n hoogtehoek van 20° is, maar daar word opgemerk dat meer as die helfte van die satellietverbyvlugte onder ’n hoogtehoek van 10° is. Aangesien Argos-satelliete nie boodskappe af stuur na IoT-platforms nie, maar slegs ontvang, kan die platvorms nie die werklike teenwoordigheid van satellite befestig nie. Nog temeer, satelliete is nie voortdurend sigbaar in plekke nader aan die ewenaar nie. Daarom is dit noodsaaklik om ’n transmissiestrategie te ondersoek om kommunikasiesukses te verbeter. ’n Transmissiestrategie word voorgestel en gesimuleer om die sukseskoers, tyd tot aflewering en kragverbruik te meet. Die simulasies toon dat die voorgestelde strategie die waarskynlikheid van uitsending terwyl ’n satellite bo die horison is, met 20% verbeter. Verder kan die proporsie uitsendings terwyl satelliete bo ’n hoogtehoek van 20° plaasvind, meer as verdubbel. Dit is gewys dat seine wat gestuur word na satelliete bo ’n hoogtehoek van 20°, verband hou met die doeltreffendheid van die uitsendings. Daar is gesien dat die verhoging van die transmissiekrag van 250mW na 1000mW nie die transmissiesukses noemenswaardig be¨ınvloed nie, maar dit het ook nie so ’n groot invloed op die batterylewe nie aangesien die kort transmissiesarsies baie selde plaasvind. Oor die algemeen dra hierdie tesis by tot die veld van satelliet-geaktiveerde bewaringstegnologie, wat praktiese insigte verskaf oor transmissiesukseskoers in verskillende toestande, asook verbeterings in transmissiestrategie¨e vir beter hulpbronbestuur voor te stel.Master
The development of a competency model for medical practitioners, with a focus on exploring situational variables during the Covid-19 pandemic : a qualitative inquiry
Get PDFThesis (MCom)--Stellenbosch University, 2025.Hoosain, K. 2025. The development of a competency model for medical practitioners, with a focus on exploring situational variables during the Covid-19 pandemic : a qualitative inquiry. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/29a074e8-aa78-4bbe-88e6-5f3635fe4a2cENGLISH SUMMARY: South Africa’s healthcare sector has faced various challenges over the years. As a result, this has placed medical practitioners, specifically those working in the public health sector under immense strain and pressure. Due to these contextual challenges, medical practitioner performance and well-being have been affected. Many had to navigate their work situations with limited resources, staff shortages and high workloads while continuing to provide care to patients. Additionally, the COVID-19 pandemic further increased the impact of these factors on medical practitioners' performance and well-being. These situations require intervention to not only solve the working conditions of medical practitioners but also to support the healthcare workforce by developing a framework to identify the factors that determine medical practitioner performance and to improve the functioning of medical practitioners and healthcare facilities in the public health sector. As these factors are complex to determine, a partial South African Medical Practitioner Competency Model is extended to gain a comprehensive understanding of the competencies, outcomes and person characteristics required for optimal performance. This study was conducted to explore the situational variables that affect medical practitioners’ work performance in South African public hospitals – during the COVID-19 pandemic. Furthermore, this study adds to this competency model by identifying how the situational work contexts of medical practitioners impact their performance. The competency model aims to depict how these variables interact to determine how performance is influenced.
An in-depth literature review was conducted on the state of South Africa’s public healthcare sector and the situational factors reported to impact medical practitioner performance before the COVID-19 pandemic and during the COVID-19 pandemic. Thereafter, a partial Medical Practitioner Competency Model was extended that illustrates the different competency latent variables, competency potential variables and situational variables that influence medical practitioner performance and how they structurally interconnect. Due to the gaps in the literature in South Africa, a specific focus is on situational variables reported to impact medical practitioner performance during the COVID-19 pandemic. This study adopted a qualitative research approach to identify the situational latent variables that impact medical practitioner performance during the COVID-19 pandemic. Medical practitioners were utilised as co-researchers in this study to confirm what was found in the literature study and to add any additional insights. The Critical Incident Technique (CIT) was used as a method of data collection through individual interviews. A sample of eleven medical practitioners provided their insights into the data collection process. Twenty-six first-order themes relating to situational latent variables were extracted by use of thematic analysis. The themes were contrasted with the situational variables identified in the literature review, and it was verified that 65% of the themes identified were additional to the situational variables identified in the literature review. Furthermore, the themes were categorised into twenty-three second-order themes. Lastly, a conceptual model is suggested that illustrates the hypothesised interrelationships between the different variables that constitute medical practitioner performance i.e., medical practitioner competence, medical practitioner outcomes, medical practitioner competency potential and the situational latent variables. The conceptual model depicts the impact of medical practitioner competencies on medical practitioner outcomes, medical practitioner competency potential variables on medical practitioner competencies and how situational variables impact medical practitioner competencies. The findings of this study can potentially inform human resource management and relevant interventions to provide favourable and conducive working conditions for medical practitioners and, ultimately, for quality patient care. However, it is important to note that this study is a hypothesis-generating study and not an empirical descriptive study. Therefore, this study paves the way for quantitative validation of the Partial South African Medical Practitioner Competency Model.AFRIKAANSE OPSOMMING: Suid-Afrika se gesondheidsorg sektor is gelas met verskeie uitdagings die afgelope paar jare. As gevolg hiervan, is mediese praktisyns onder geweldige druk en stres blootgestel, veral dié werksaam in die publieke gesondheidsorgsektor. Dit het ook ‘n impak op mediese praktisyn welstand en prestasie gehad. Baie praktisyns moes werk situasies met beperkte hulpbronne, personeel tekorte en oorweldigende werksladings bestuur terwyl daar steeds sorg aan pasiente gelewer moes word. Daarmeesaam, gegewe die COVID-19 pandemie, was die impak van hierdie faktore vererger, veral op mediese praktisyn prestasie en welstand. Hierdie situasies het ‘n intervensie benodig, nie net om die werkskondisies van mediese praktisyns te verbeter nie, maar ook om hulle te ondersteun. ‘n Raamwerk word benodig om faktore te identifiseer wat mediese praktisyn prestasie kan bepaal asook die verbetering van mediese praktisyn en gesondheidsorgfasiliteite in die publieke gesondheidsorg sektor. Aangesien dit kompleks is om hierdie faktore te bepaal, is ‘n gedeeltelike Suid-Afrikaanse Mediese Praktisyn Bevoegdheidsmodel uitgebrei om sodoende ‘n volledige begrip van die bevoegdhede, uitkomste en persoon karaktereinskappe vir optimale prestasie te kry. Die studie was gedoen om situasionele veranderlikes wat mediese praktisyn werksprestasie affekteer in Suid Afrikaanse openbare hospitale te verken – gedurende die COVID-19 pandemie. Verder is hierdie studie is ‘n bydrae tot the bevoegdheidsmodel deurdat situasionele werksdimensies geidentifiseer is, wat prestasie beinvloed. Die bevoegdheidsmodel het ten doel om aan te dui hoe hierdie dimensies mekaar beinvloed en hoe prestasie dus beinvloed word. ‘n In-diepte literatuur studie was gedoen rondom die toestand van die Suid-Afrikaanse publieke gesondheidsorgsektor, asook die situasionele dimensies wat ‘n impak op mediese praktisyn prestasie het, voor en tydens die COVID-19 pandemie. Daarna is ʼn gedeeltelike mediese praktisyn bevoegdheidsmodel uitgebrei wat die verskillende bevoegdheid latente veranderlikes, bevoegdheid potensiaal veranderlikes en situasionele veranderlikes aandui asook hoe hierdie veranderlikes struktureel onderling verbind is. As gevolg van die gapings in die literatuur in Suid-Afrika, is ʼn spesifieke fokus gerapporteer wat kyk na die impak van situasionele veranderlikes op mediese praktisyn prestasie gedurende die COVID-19 pandemie. Die studie volg ʼn kwalitatiewe benadering om sodoende die situasionele latente veranderlikes the identifiseer wat ʼn impak het op mediese praktisyn prestasie gedurende die COVID-19 pandemie. Mediese praktisyns was gebruik as mede-navorsers in die studie om te bevestig wat in die literatuur gevind was, maar ook nuwe insigte te deel. Die Kritieke Insident Tegniek (KIT) was as data insamelingsmetode gebruik in samehang met ʼn onderhoud. ʼn Steekproef van elf mediese praktisyns het hulle insig in die data insamelingsproses gedeel. Ses-en-twintig eerste orde temas verbandhoudend met situasionele veranderlikes was met behulp van tematiese analise ontrek. Hierdie temas was vergelyk met temas wat geidentifiseer was in die literatuur oorsig; 65% van die temas was egter addisioneel tot die situasionele veranderlikes soos geidentifiseer in die literatuur oorsig. Die temas is toe gekategoriseer in ʼn verdere drie-en-twintig tweede orde temas. Ten laaste is ʼn konseptuele model voorgestel wat die gehipotetiseerde onderlinge verwantskappe illustreer tussen verskillende veranderlikes wat mediese praktisyn prestasie impakteer byvoorbeeld, mediese praktisyn bevoegdheid, mediese praktisyn uitkomste, mediese praktisyn bevoegdheidspotensiaal en situasionele latente veranderlikes. Die konseptuele model gee ʼn uitbeelding van die impak van mediese praktisyn bevoegdhede op mediese prestasie uitkomste, mediese bevoegdheidspotensiaal veranderlikes op mediese praktisyn bevoegdhede en hoe situasionele veranderlikes, mediese praktisyn bevoegdhede impakteer. Die bevindinge van die studie kan potensieel as inligting dien vir menslike hulpbron bestuur asook vir relevante intervensies wat dalk meer gunstige en ondersteunende werkskondisies vir mediese praktisyns kan bied, en uiteindelik ook kwaliteit pasientesorg affekteer. Dit is egter belangrik om daarop te let dat hierdie studie hipotese-genererend van aard is en nie ʼn empiriese beskrywende studie nie. Hierdie studie baan die weg vir kwantitatiewe validering van die Gedeeltelike Suid-Afrikaanse Mediese Praktisyn Bevoegdheidsmodel.Master
An investigation into plant (Juncus effusus) biofilter nitrification modelling
Get PDFMunhemba, T. 2025. An investigation into plant (Juncus effusus) biofilter nitrification modelling. Unpublished doctoral dissertation. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/2d2e8b91-da74-4348-b322-9e343ff3d2f5Thesis (PhD)--Stellenbosch University, 2025.ENGLISH ABSTRACT: This research investigates the removal of ammonia from stormwater using biofilters planted with the native South African species, Juncus effusus. Ammonia, a significant nitrogen-based contaminant, poses a major challenge in stormwater management, and this research addresses that challenge by developing a conceptual model and applying it to a laboratoryscale biofilter prototype. This prototype integrates critical processes, including nitrogen fixation, plant uptake, bacterial nitrification, and soil sorption, all aligned with the conceptual framework. A key innovation in the prototype design is the incorporation of a plug compartment, implemented to emulate plug flow dynamics, an integral aspect of the conceptual model. The efficacy of the biofilters, both with and without inoculated bacteria, was compared. The results showed a substantial improvement in ammonia removal for the biofilter that was enriched with the inoculated bacteria, achieving a 61% concentration reduction in ammonia as N, compared to only 15% in non-inoculated setups. Building upon these findings, a nitrification model was developed using a mass balance approach, integrating microbial nitrification, plant uptake, and soil sorption processes. Various laboratory configurations, based on the initial prototype design, were tested to establish model parameters. The study explored the role of rhizosphere bacteria in improving nitrification efficiency. Two biofilm flux models: a fully penetrated model and a partially penetrated model, based on ammonia concentrations measured either in the influent or within the plug compartment of the biofilter were developed. The fully penetrated model and partially penetrated model with ammonia influent as a parameter showed a fit with the experimental results and were further tested in full-scale experiments. The model was validated through a series of experimental runs using different ammonia concentrations (2.5-15 mg/L). The model could predict an upper and lower limit for ammonia mass effluent as N, with most measured effluent values falling between the two predicted ranges. Statistical analysis confirmed the model's validity for stormwater applications. The study concludes with recommendations for refining the model and provides guidelines for practical implementation of these biofilters. This research contributes to the development of green infrastructure and sustainable stormwater management solutions.AFRIKAANSE OPSOMMING:Hierdie navorsing ondersoek die verwydering van ammoniak uit stormwater deur biofilters met die inheemse Suid-Afrikaanse plantsoort Juncus effusus. Ammoniak, 'n beduidende stikstofgebaseerde besoedelstof, stel 'n groot uitdaging in stormwaterbestuur, en hierdie navorsing spreek daardie uitdaging aan deur 'n konseptuele model te ontwikkel en dit toe te pas op 'n laboratoriumskaal-biofilterprototipe. Die prototipe integreer kritiese prosesse soos stikstofbinding, plantopname, bakteriële nitrifikasie, en grondsorpsie, wat alles volgens die konseptuele raamwerk geïntegreer is. 'n Sleutelinnovasie in die ontwerp van die prototipe is die insluiting van 'n propkompartement, wat ontwerp is om propvloeidinamika na te boots, 'n integrale aspek van die konseptuele model. Die doeltreffendheid van die biofilters, beide met en sonder geïnokuleerde bakterieë, is geëvalueer en vergelyk. Die resultate het getoon dat die biofilter met geïnokuleerde bakterieë 'n aansienlike verbetering in ammoniakverwydering behaal het, met 'n 61%-vermindering in vergelyking met slegs 15% in nie-geïnokuleerde opstellings. Benewens die vermindering van ammoniak, het die sisteem ook die vorming van nitriete en nitrate bevorder. Gebaseer op hierdie bevindings, is 'n nitrifikasiemodel ontwikkel met behulp van 'n massabalansbenadering, wat mikrobiële nitrifikasie, plantopname en grondsorpsieprosesse geïntegreer het. Verskeie laboratoriumopstellings, gebaseer op die aanvanklike prototipeontwerp, is getoets om modelparameters te bepaal. Die studie het ook die rol van risosfeer-bakterieë in die verbetering van nitrifikasie-doeltreffendheid ondersoek deur twee biofilmvloeimodelle toe te pas: 'n volledig gepenetreerde model en 'n gedeeltelik gepenetreerde model, gebaseer op ammoniakkonsentrasies wat óf in die invloei óf in die propkompartement van die biofilter gemeet is. Albei modelle het 'n sterk ooreenstemming met die eksperimentele resultate getoon en is verder getoets in grootskaalse eksperimente. Die model is gevalideer deur 'n reeks eksperimentele lopies met verskillende ammoniakkonsentrasies (2.5-15 mg/L). Die resultate het getoon dat die model betroubaar 'n boonste en onderste grens vir ammoniak-uitvloeisel kon voorspel, met die meeste gemete uitvloeiwaardes wat tussen die twee voorspelde reekse val. Statistiese ontledings het die model se geldigheid vir stormwater-toepassings bevestig. Die studie sluit af met aanbevelings vir die verfyning van die model en verskaf riglyne vir die praktiese implementering van hierdie biofilters. Hierdie navorsing dra beduidend by tot die ontwikkeling van groen infrastruktuur en volhoubare stormwaterbestuuroplossings.Doctora