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Characterization of the structural, optical and electrical properties of ZnO:re3+/FWCNT/P3HT nanocomposite for possible application in organic solar cells
Get PDFThe structure, morphology, optical, and electrical characteristics of rare earth (RE) metal ions, few-walled carbon nanotubes (FWCNT) and zinc oxide (ZnO) nanocomposite for possible applications such as electron acceptor in the active layer of organic solar cells are described in this study. ZnO nanotubes were created utilizing a microwave-assisted sol-gel technique with 1-Thioglycerol (TG) as a capping agent. To explore the effect of dopants in ZnO nanorods, the amounts of impurities or dopants were changed and integrated into a conjugated virgin poly(3-hexylthiophene) polymer (P3HT).
The surface morphology, crystal structure, optical absorption, photoluminescence (PL) and current-voltage (I-V) properties were influenced by dopants, ZnO/FWCNT nanocomposite and the incorporation of P3HT. The Field emission scanning electron microscopy (FE-SEM) showed the homogeneous nanorods morphology of ZnO, and the inclusion of P3HT dispersed the morphology into mixed structures of nanorods. X-ray diffraction (XRD) results showed that ZnO despite being doped or incorporated with P3HT, the nanorods have hexagonal wurtzite structure. X-ray photoelectron spectroscopy (XPS) revealed a strong interaction between P3HT and ZnO. All of the functional groups in the materials were visible using Fourier-transform infrared (FTIR). P3HT-ZnO doped with rare earth ions and P3HT/ZnO/FWCNT have a good property of the interaction that leads to a good mixing of ligands. The UV/VIS/NIR absorption findings demonstrated a significant improvement in absorption, providing additional chances for improved efficiency in organic solar cells. This is due to an increase in doping concentration and the integration of P3HT-ZnO at various ratios. The photoluminescence quenching effect of PL was considerable, suggesting that it might be used as an electron acceptor in the active layer of an organic photovoltaic (OPV) system. The I-V curve demonstrated an increase in electrical conductivity, indicating that these materials (P3HT-ZnO) at different ratios, an increase in rare earth doping concentration, and FWCNT) are prime candidates for accelerating electron transport, lowering electron-hole recombination, and improving the efficiency of organic solar cells (OSCs).
In this work, rare earth ions and FWCNT doped ZnO were combined with P3HT, and the introduction of P3HT considerably reduces the PL intensity, indicating a charge transfer between donor and acceptor materials. This combination serves to specifically amplify and enhance electron transfer and electrical conductivity for possible use in OSCs. Moreover, this combination of materials has a strong photoluminescence quenching effect indicating a good charge separation in the photoactive layer of the organic solar cell device.D. Sc. (Physics)Physic
Moodle in an Open Distance e-Learning University : is it a building or stumbling block to student interaction and autonomy?
Get PDFHigher education institutions (HEIs) in Africa are seemingly staggering under
the burden of digital division and exclusion. Due to its perceived flexibility and
affordability for students in remote areas, distance education is a popular option
for many students at HEIs. One of the e-learning tools introduced is a modular
object-oriented dynamic learning environment (Moodle) learning management
system (LMS), which is designed using web-based applications and provides
online learning services to students. The key question remains: how do firstyear students experience Moodle? Do they view it as a building block to their
learning? Or is it a stumbling block? This article reports on a study that was
conducted in a South African open distance e-learning (ODeL) institution with
students who speak English as an additional language, in an Academic Writing
module. The study used a qualitative case study approach and drew on the
theory of transactional distance to understand how Moodle encourages student
interaction and autonomy. Although the study findings cannot be generalised on
a broader scale, the findings are in line with similar studies, amplifying the
critical role of student experiences, interaction, and autonomy in HEIs to bring
about the required change.English Studie
The relationship between visual literacy and science literacy among English second language pre-primary school learners
No full textEarly exposure to science-related content through visual literacy has the potential to enhance the interest in science among South African learners, particularly those who find the subject complex. Visual representation serves as valuable instructional support, stimulating learner engagement and facilitating meaningful science learning. The primary objective of this study was to assess the levels of visual literacy, science literacy, and scientific reasoning ability among pre-primary school learners, with the aim of supporting the effective integration of visual representations in science education. The research was underpinned by the Cognitive Theory of Multimedia Learning, which served as the theoretical framework to investigate the feasibility of integrating science education in pre-primary school using visual literacy. The research adopted a mixed-method approach, employing a purposive sampling method to select a sample of 208 Grade R learners from non-government English Medium Language preprimary
schools in Bloemfontein, South Africa. Quantitative data were collected through a survey questionnaire consisting of psychometric and content knowledge tests, while qualitative data were obtained via semi-structured interviews. The findings indicated that learners from
STEM schools demonstrated higher levels of visual literacy, science literacy, and scientific reasoning ability. However, no significant positive relationship was observed between visual literacy and science literacy, challenging the assumption that early science education
contributes to visual literacy development. In conclusion, it is crucial to prioritize the development of visual literacy and science literacy in pre-primary school, despite the absence of a significant positive relationship between the two. Early exposure to science education offers valuable benefits for cognitive development and future scientific pursuits. To promote comprehensive understanding and enhance scientific reasoning skills, it is recommended to
integrate visual literacy activities and science content into pre-primary school curricula, utilizing age-appropriate visuals, interactive materials, and engaging instructional strategies.Ph. D. (Natural Science Education)Science and Technology Educatio
An analysis of climate change adaption strategies: a case study of smallholder farmers in Limpopo province, South Africa
No full textClimate change is a worldwide problem as it affects agriculture which is the livelihood of the poor. The study used the Protection Motivation Theory to understand how smallholder farmers protect themselves from climate change impacts and what motivates them to do so. The purpose of this exploratory sequential mixed method design was, firstly, to explore and understand climate change through the insights and experiences of smallholder farmers and government officials in Limpopo Province. Secondly, to uncover and assess smallholder farmers' adaptation techniques to varied climatic circumstances.
This was a case study that used a mixed approach following two phases. To collect data, 62 smallholder farmers under Ba-Phalaborwa Local Municipality and 12 key informants from Limpopo Department of Agriculture and Rural Development were chosen using purposive and random selection. Questionnaires, a focus group guide, key informant interviews, and field observations were used to collect data from both qualitative and quantitative phases. The mixed data analysis used joint data displays, which exhibited findings from qualitative and quantitative data together for an overall research interpretation. Extreme climatic events; high socioeconomic losses; a lack of resources; limited adaptation techniques; and agricultural investment were the themes found in this study. These themes developed the questionnaires to collect quantitative data.
Climate change has a detrimental impact on smallholder farmers owing to a lack of physical, human, institutional and financial resources. Smallholder farmers hardly survived climate shocks due to inadequate institutional support. These impediments limited smallholder farmers' capacity to adopt and apply several adaptation strategies. Despite that smallholder farmers adopted cost free strategies, such as manure, mulching, crop rotation and planting indigenous crops, to survive harsh climate impacts, strategy such as drilling borehole has been found to be maladaptive, possibly to cost government lots of money in the future due to a reduced groundwater level. Hence, there is need
viii
for decision makers to improve and strengthen climate adaptation policies.
Moreover, the findings revealed that Limpopo Province experiences climatic events such as heavy rainfall, droughts, thunderstorms, floods and veld fires. Hence, educating farmers about climate change has been found to be a pre-requisite. Limited collaboration between government departments was found to be the reason for the lack of availability and accessibility to resources to farmers. Harsh climate conditions can be managed if stakeholders pool their resources for the benefit of farmers and to boost the economic growth of the country.Development Studie
The challenges in the professional development of TVET college lecturers in Limpopo Province of South Africa
No full textTVET colleges are an important part of a quality education system that can offer much needed opportunities for school leavers. The main purpose of the study was to explore the professional development state in the Limpopo TVET colleges to establish plans that can be applied to improve the professional development of lecturers at TVET colleges in South Africa in general.
A qualitative research approach and an exploratory research design was used in this study. The interviews analysis with both the college management presented by participants CM1 and CM3 and the teaching staff represented by participants L1, L2, L4, SL1, SL2 and SL3 were deliberated in this chapter. This chapter also addressed the views of college management and teaching staff as backed by literature. Out of ten (10) participants, two (2) participants (CM2 and L3) did not manage to take part in the study. Participant CM2 did not make it due to ill health and participant L3 did not participate due to personal reasons. To obtain primary data from participants to investigate the challenges in the professional development of TVET college lecturers in the Limpopo Province of South Africa, semi-structured interviews was used. Responses from both management and lecturers show that there is a lack of certain skills and knowledge in both management and teaching. Senior management must accept full responsibility in implementing professional development courses to improve standard teaching and learning and must arrange and implement professional development courses to empower their lecturing staff. Lectures need to be empowered on how best they can improve their teaching skills using latest technology. But they acknowledge that through professional development courses by management, teaching skills can improve. The findings reveal that a lot still needs to be done to improve the situation in TVET colleges. That is because even though the management and lecturers agree with professional development to address their challenges, the planning and implementation still need more attention.
The study recommended that for college management to execute their leadership duties more effectively, there is a need to provide rigorous training programmes in terms of the significance and consequences of professional development in the college. The senior management should take up the significance of implementing professional development courses to improve standard teaching and learning. They must arrange and implement professional development courses to empower the lecturing staff. The study also advocated that individual lecturers be anticipated to have detailed understanding of the subjects they are involved in. The study decided that professional development in the Limpopo Province TVET colleges require careful planning and implementation for the advantage of the college, economy, the students, lecturers and the nearby communities.M. Ed. (Adult Education)Adult Basic Education (ABET
Iterated function systems in partial metric spaces with applications
Get PDFBibliography: pages 151-158The mathematical study of fractals is deeply embedded in iterated function systems
(IFS) formulated by Hutchinson in 1981. Since then, the development of
iterated function systems in metric space setup, has caught the attention of many
researchers.
In the current work, the scope of iterated function systems is extended to more
generalized settings such as partial metric spaces, Hausdor semi-metric spaces,
and G-metric spaces. The existence and uniqueness of new attractors and common
attractors of generalized iterated function systems in various spaces is proved
with the assistance of generalized and generalized cyclic contractive mappings.
Well-posedness of attractor based problems of the Hutchinson operators is established.
Applications to dynamic programming and nonlinear integral equations
are presented.D. Phil. (Applied Mathematics)Mathematical Science
Global private sector philanthropy in the developing world: the giving motives of international private foundations to South Africa’s development landscape
No full textThere is a growing interest in the role of the private sector in international development cooperation. Global development commitments, including the 2030 Sustainable Development Goals (SDGs), call for the private sector aid to help governments meet their developmental targets. In an era of shrinking official development aid and a changing aid architecture, philanthropic foundations are amongst the private sector actors expected to play a significant role in financing development initiatives; while some of these entities and initiatives are not necessarily new, available literature shows that they remain relatively unknown, therefore their role and impact in development cooperation is not well understood. The lack of empirical knowledge about their activities breeds many questions around their corporate origin, relevance and their motives for giving. This study seeks to contribute to the body of knowledge on global private development assistance by exploring the giving motives of international private foundations to South Africa’s development landscape.
Findings of the study were from interviews with representatives of 8 international foundations from OECD countries operating in South Africa. The study also explored available secondary data on these organisations and consulted other sector players to help provide the data. The study adopted traditional development aid theories used to assess determinants of bilateral and multilateral aid, to explore international foundations’ giving motives. The study’s findings indicate that international foundations are motivated by a duality of factors reflecting not only their desire to meet the developmental needs of recipient countries but also to archive their other interests, such as, aligning with the altruistic moral values of a private founder, corporate citizenship and other indirect corporate benefits. The study also found that creating a relationship between the sending country and recipient is also an important factor for giving; donors at the same time benefits from good company reputation and a social license to operate in the receiving country. After concluding, the study makes various recommendations, including the need for further empirical investigation on the role and overall impact of private philanthropy.D. Phil. (Development Studies)Development Studie
Profiling momentum in equity markets
No full textIncludes summaries in Afrikaans and isiZuluThis study created a customised model and a custom index to profile momentum in
equity markets. The customised model used a momentum term structure grouped into
different entry zones to create visual profiles for individual equity shares or
stocks. A momentum profile describes a particular equity market in terms of the
composition of its momentum cycles. Profiling shifts the focus onto the holding
period while differentiating between false, neutral, negative, and positive
momentum cycles as determined by the eventual outcomes. The composition of the
momentum cycles and average hold per cycle type provide a unique description of the
momentum effect in a market. The customised model identifies the stocks with
momentum cycles in progress while the custom index quantifies the collective outcome
to show the progression of momentum in a market over the years. Therefore, each
equity market has a different profile related to the composition of its momentum
cycles and the performance of its custom index. These profiles can be compared in
terms of the number of momentum cycles, composition, basic profiles (average holds,
price ranges, sectors, and entry zones), average parameter scores, and performance.
This study created momentum profiles for three different equity markets – the
Johannesburg Stock Exchange (JSE), the Toronto Stock Exchange (TSX), and the TSX
Venture Exchange. The settings of the model parameters (momentum, volatility,
quality, and activity scores) were calibrated on data from the JSE to enable direct
comparison between the three exchanges. These exchanges or markets are distinct in
size, the number of qualifying listings, and the number of listings that generated
momentum cycles. The composition or configuration of the momentum cycles is unique
to each market. The overall outcomes, in terms of average hold and compound return
per average hold, favoured the emerging market represented by the Johannesburg
Stock Exchange (JSE). The developed market, represented by the Toronto Stock
Exchange (TSX) generated the largest number of momentum cycles and outperformed the
JSE based on positive cycles. The venture market, represented by the TSX Venture
Exchange (TSXV), underperformed the other two markets overall but produced the best
results in terms of positive cycles. The positive cycles ultimately determined the
performance of the respective momentum indices with the TSXV Momentum Index (TSXV MI) outperforming the other two indices, the JSE Momentum Index (JSE-MI) and the
TSX Momentum Index (TSX-MI) over the 13-year period (2009-2021) of analysis.Hierdie studie het 'n doelgemaakte model en 'n pasgemaakte indeks geskep om momentum
in aandelemarkte te profileer. Die doelgemaakte model het 'n momentumtermynstruktuur
gebruik wat in verskillende toetreesones ingedeel is om visuele profiele vir
enkelaandele te skep. 'n Momentumprofiel beskryf 'n besondere aandelemark in terme van
die samestelling van sy momentumsiklusse. Profilering verskuif die klem na die
houtydperk terwyl daar onderskei word tussen vals, neutrale, negatiewe en positiewe
momentumsiklusse soos bepaal deur die uiteindelike uitkomste. Die samestelling van die
momentumsiklusse en gemiddelde houtyd per siklussoort verskaf 'n eiesoortige of unieke
beskrywing van die momentumeffek in 'n mark. Die doelgemaakte model wys die aandele
met ontwikkelende momentumsiklusse uit, terwyl die pasgemaakte indeks die gesamentlike
uitkoms kwantifiseer om die vordering van momentum in 'n mark oor die jare weer te gee.
Elke aandelemark het daarom 'n anderse profiel wat verband hou met die samestelling
van sy momentumsiklusse en die vertoning van sy pasgemaakte indeks. Hierdie profiele
kan vergelyk word in terme van die aantal momentumsiklusse, samestelling, basiese
profiele (gemiddelde houtye, prysklasse, sektore en toetreesones), gemiddelde
parametertellings en vertoning. Hierdie studie het momentumprofiele vir drie
verskillende aandelemarkte geskep – die Johannesburg Aandelebeurs (JSE), die Toronto
Aandelebeurs (TSX) en die TSX Waagkapitaalbeurs. Die stellings van die modelparameters
(momentum, volatiliteit, kwaliteit en aktiwiteit tellings) is op data van die JSE
ingestel om direkte vergelyking tussen die drie beurse moontlik te maak. Hierdie beurse
of markte is verskillend in grootte, die aantal geskikte noterings en die aantal
noterings wat momentumsiklusse ondergaan het. Die samestelling of konfigurasie van die
momentumsiklusse is eiesoortig aan elke mark. Die algehele uitkomste, in terme van
gemiddelde houtyd en saamgestelde opbrengs per gemiddelde houtyd, het die ontluikende
mark soos deur die Johannesburg Aandelebeurs (JSE) verteenwoordig bevoordeel. Die
ontwikkelde mark, verteenwoordig deur die Toronto Aandelebeurs (TSX), het die grootste
aantal momentumsiklusse voortgebring en het beter as die JSE gevaar op grond van
positiewe siklusse. Die waagmark, verteenwoordig deur die TSX Waagkapitaalbeurs (TSXV),
het oor die algemeen swakker gevaar as die ander twee markte, maar het die beste uitslag
gelewer in terme van positiewe siklusse. Die positiewe siklusse het uiteindelik die
vertoning van die onderskeie momentumindekse bepaal met die TSXV Momentum Indeks (TSXV MI) wat die ander twee indekse, die JSE Momentum Indeks (JSE-MI) en die TSX Momentum
Indeks (TSX-MI), oor die 13-jaar tydperk (2009-2021) van ontleding oortref.Lolu cwaningo ludale imodeli eyenziwe ngokwezifiso kanye nenkomba yangokwezifiso ukuze
kuphrofayili umfutho ezimakethe zokulingana. Imodeli eyenziwe ngendlela oyifisayo
isebenzise ukwakheka kwethemu lomfutho eliqoqwe ezindaweni zokungena ezihlukene ukuze
kwakhe amaphrofayili abonakalayo wamasheya angawodwana okulingana noma amasheya.
Iphrofayili yomfutho ichaza imakethe ethile yezabelomali ngokuya ngokwakheka kwemijikelezo
yayo yomfutho. Ukwenza iphrofayela kushintsha ukugxila kunkathi yokubamba kuyilapho
kuhlukanisa phakathi kwemijikelezo yamanga, engathathi hlangothi, engemihle, kanye nenhle
njengoba kunqunywa imiphumela yokugcina. Ukwakheka kwemijikelezo yomfutho nokubamba
okumaphakathi kohlobo ngalunye lomjikelezo kunikeza incazelo ehlukile yomthelela womfutho
emakethe. Imodeli eyenziwe ngendlela oyifisayo ikhomba amasheya anemijikelezo yomfutho
eqhubekayo kuyilapho inkomba yangokwezifiso ilinganisela umphumela ohlangene ukuze ubonise
ukuqhubeka komfutho emakethe phakathi neminyaka. Ngakho-ke, imakethe yezabelomali ngayinye
inephrofayili ehlukile ehlobene nokwakheka kwemijikelezo yayo yomfutho kanye nokusebenza
kwenkomba yayo yangokwezifiso. Lawa maphrofayili angafaniswa ngokwenani lemijikelezo
yomfutho, ukwakheka, amaphrofayili ayisisekelo (ukubanjwa okumaphakathi, ububanzi
bentengo, imikhakha, nezindawo zokungena), isilinganiso semiphumela yepharamitha, kanye
nokusebenza. Lolu cwaningo ludale umfutho ezimakethe ezintathu ezahlukene zamasheya –
iJohannesburg Stock Exchange (JSE), iToronto Stock Exchange (TSX), kanye ne-TSX Venture
Exchange. Izilungiselelo zamapharamitha wemodeli (umfutho, ukuguquguquka, ikhwalithi,
namaphuzu omsebenzi) zilinganiswa ngedatha evela e-JSE ukuze kuvunyelwe ukuqhathanisa
okuqondile phakathi kwalokhu kushintshana okuthathu. Lokhu kushintshana noma izimakethe
zihlukile ngosayizi, inombolo yokufakwa kuhlu okufanelekayo, kanye nenani lokufakwa kuhlu
okukhiqize imijikelezo yomfutho. Ukwakheka noma ukucushwa kwemijikelezo yomfutho
bekuhlukile emakethe ngayinye. Isiyonke imiphumela, ngokwesilinganiso sokubamba kanye
nembuyiselo ehlanganisiwe ngokwesilinganiso sokubamba, ivune izimakethe ezisafufusa
ezimelwe yiJohannesburg Stock Exchange (JSE). Imakethe ethuthukisiwe, emelwe yi-Toronto
Stock Exchange (TSX) ikhiqize inani elikhulu kakhulu lemijikelezo yomfutho futhi yadlula
i-JSE ngokusekelwe emijikelezweni emihle. Imakethe yezohwebo, emelwe yi-TSX Venture
Exchange (TSXV), yenza kabi ezinye izimakethe ezimbili zizonke kodwa yakhiqiza imiphumela
engcono kakhulu ngokwemijikelezo emihle. Imijikelezo eqondile igcine inqume ukusebenza
kwezinkomba zomfutho ngokulandelana kwazo ne-TSXV Momentum Index (TSXV-MI) idlula ezinye
izinkomba ezimbili, i-JSE Momentum Index (JSE-MI) kanye ne-TSX Momentum Index (TSX-MI)
phakathi neminyaka 13 unyaka inkathi (2009-2021) yokuhlaziya.D. Phil. (Management Studies)Business Manangemen
Students' perceptions on the adoption of online communication channels within a South African higher learning institution
Get PDFThis study sought to establish students’ perceptions regarding the adoption of online communication channels for virtual learning at the University of Johannesburg. The study also explored the efficacy of online communication channels used for teaching and learning, as virtual learning was thrust upon the education sector owing to the Covid-19 pandemic. Online learning still encounters challenges within the South African context. The study used a quantitative method. The target population was 80 students at the University of Johannesburg in the School of Communication. The participants were selected through simple random sampling. Data was gathered using a web-based questionnaire and analysed with descriptive statistics using SPSS and MS Excel. The results show that online communication channels were improving teaching and learning. In addition, the study found that loadshedding was not affecting virtual learning. The study concludes that virtual learning is an effective method for delivering teaching and learning.M.A. (Communication Science)Communication Scienc
Measurement of the properties of Higgs boson production at s = 13 TeV in the H → γγ channel using 139 fb−1 of pp collision data with the ATLAS experiment
No full textAbstract
Measurements of Higgs boson production cross-sections are carried out in the diphoton decay channel using 139 fb−1 of pp collision data at
s
= 13 TeV collected by the ATLAS experiment at the LHC. The analysis is based on the definition of 101 distinct signal regions using machine-learning techniques. The inclusive Higgs boson signal strength in the diphoton channel is measured to be
1.04
−
0.09
+
0.10
. Cross-sections for gluon-gluon fusion, vector-boson fusion, associated production with a W or Z boson, and top associated production processes are reported. An upper limit of 10 times the Standard Model prediction is set for the associated production process of a Higgs boson with a single top quark, which has a unique sensitivity to the sign of the top quark Yukawa coupling. Higgs boson production is further characterized through measurements of Simplified Template Cross-Sections (STXS). In total, cross-sections of 28 STXS regions are measured. The measured STXS cross-sections are compatible with their Standard Model predictions, with a p-value of 93%. The measurements are also used to set constraints on Higgs boson coupling strengths, as well as on new interactions beyond the Standard Model in an effective field theory approach. No significant deviations from the Standard Model predictions are observed in these measurements, which provide significant sensitivity improvements compared to the previous ATLAS results