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Mechanical recyclability and biodegradation of biopolymers, biopolymer blends and biocomposite in natural environmental conditions
Get PDFThe present research aimed at investigating mechanical recyclability and studying the potential biotic and abiotic degradation behaviors of biobased biodegradable polymers in different environmental conditions. The mechanical recyclability tests monitored the effect of multiple reprocessing on the mechanical, thermal, physical, chemical, and morphological properties of poly (butylene adipate-co-terephthalate) (PBAT), poly (butylene succinate) (PBS), poly (lactic acid) (PLA), PBAT-PBS blend, and PBAT-thermoplastic starch (TPS) composite. Low-density polyethylene (LDPE), a conventional non-biodegradable plastic, was also monitored for comparison studies. The mechanical recyclability tests were carried out by eight melt extrusion cycles using twin-screw extrusion and injection molding processing techniques. Tensile testing, impact analysis, melt flow index test (MFI), differential scanning calorimetry (DSC), thermogravimetry (TGA), dynamic mechanical analysis (DMA), Fourier Transform Infrared Spectroscopy (FTIR) and scanning electron microscopy (SEM) techniques were employed to monitor the effect mechanical recycling at each melt extrusion cycle. Tensile and impact strength results showed that PBAT and PBAT-TPS biocomposite were mechanical recyclable for at least eight cycles and this was comparable to LDPE recyclability performance. In contrast, neat PBS, PLA, and PBAT-PBS blend were found to be melt extrudable only up to six cycles as the mechanical properties declined with the increase of reprocessing cycles. MFI tests suggest that molecular weight of PBAT and PBAT-TPS were not significantly affected by multiple extrusion cycles while the melt flow properties of PBS, PLA, and PBAT-PBS samples were affected from third cycle. DSC, TGA, and DMA demonstrated that PBAT and PBAT-TPS were more thermo-mechanically stable than PBS, PLA, and PBAT-PBS blend. FTIR spectroscopy results showed that the chemical structure of both PBAT and PBAT-TPS were unaffected by the multiple recycling cycles typically indicated by characteristic peak vibrations bands of C=O and C-O around 1710 cm-1 and 1046-1100 cm-1, respectively. SEM micrographs of PBS, PLA, and PBAT-PBS clearly evidenced the degradation of the biopolymers by severely fractured morphology as a result multiple reprocessing cycle.The rate of aerobic biodegradation for PBAT-PBS and PBAT-PLA blends was examined under controlled home and industrial composting using the CO2 evolution respirometric method. FTIR, DSC, TGA, X-ray diffraction analysis (XRD), and SEM were employed to monitor the changes in the structural, chemical, thermal, and morphological characteristics of the biopolymer blends before and after biodegradation. The biodegradation tests showed that PBAT-PBS and PBAT-PLA blends exhibited higher degradation rates under industrial composting conditions than under home composting conditions. The increased intensity of hydroxyl and carbonyl absorption bands on the FTIR spectra confirmed that the biodegradation process occurred. SEM revealed that there was microbial colony formation and disintegration on the surfaces of the biopolymer blends. Moreover, abiotic degradation results suggested that thermal and hydrolytic conditions influence the degradation process than sunlight exposure. Additionally, aquatic biodegradation results showed that PBAT-PBS blend and PBAT-TPS composite undergo a higher rate of biodegradation as compared to PBAT, PBS, and PLA.The results obtained from this research work conclude that biobased biodegradable polymers can be mechanically recycled, and they are suitable for biological degradation in industrial composting, home composting and marine environment.Thesis (MSc) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 202
Nagoya Protocol and Africa’s willingness to share biological control agents, are we deterred by barriers instead of using opportunities to work together?
Get PDFAmongst members of the biological control community there is a range of perceptions regarding the Nagoya Protocol, at best it will hinder access to natural enemies of pests and invasive plants and at worst implementation of the Protocol will prevent access to these resources. In this preliminary study of Africa’s preparedness to implement the Nagoya Protocol and control access to potential biological control agents, we found that several countries have not yet established procedures and policies in this regard. Several factors including lack of awareness, insufficient relevant information and lack of capacity may cause delay in countries implementing access and benefit sharing legislation and processes. The lack of preparedness provides an opportunity for the research community to work with government officials to facilitate future access to natural enemies to act as biological control agents on invasive plants and agricultural pests. Collaboration between researchers, managers and bureaucrats in support of African countries could lead to collective action that develops policies and implements processes to foster exploration of African biodiversity. This collaboration could also foster the sharing of biological control agents that will benefit Africa through integrated pest management in agriculture, protection of human lives and livelihoods, and reduction of the impact of invasive alien species on biodiversity and environmental infrastructure
Using the indigenous technology of making oshikundu to mediate learning of the topic diffusion in Namibia
Get PDFThe Namibian Science curriculum acknowledges that indigenous knowledge (IK) is an important basis for learning science. Among the shared reasons is that it provides learners with access to abstract scientific concepts. As a result, teachers are encouraged to integrate IK into the teaching and learning of science. However, it seems that there are no explicit guidelines on how IK should be integrated into science classrooms. It is against this backdrop that this study sought to explore how the indigenous technology of making oshikundu (a non-alcoholic beverage) can be mobilised by Grade 8 Life Science teachers to mediate learning of diffusion in their classrooms. The study was underpinned by interpretive and indigenous research paradigms. Within these paradigms, a qualitative case study approach was employed. Four Grade 8 Life Science teachers from four different schools in Okahandja town, Otjozondjupa Region, Namibia, participated in this study. Additionally, an expert community member who was knowledgeable about the indigenous technology of making oshikundu was requested to demonstrate how to make it. In this event, the Life Science teachers had to identify the science concepts embedded in the practice. To gather data, this study made use of semi-structured interviews, workshop discussions, observations and journal reflections. Vygotsky’s sociocultural theory was used as a theoretical framework and Mavhunga and Rollnick’s topic-specific pedagogical content knowledge (TSPCK) was used as an analytical framework. The findings of this study revealed that the teachers’ understanding was positively influenced by the integration of IK which certainly assisted them to relate better to the concept of diffusion. This was validated when teachers extracted emerging science concepts from the indigenous technology of making oshikundu. The implication of this study is that expert community member presentations can greatly enhance sense making of science concepts. The study thus recommends that school-based teachers’ continuing professional development in collaboration with expert community members should be carried out to enhance both the teachers’ subject content knowledge and pedagogical content knowledge on IK integration.Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 202
The effects of short-duration overnight kraaling on herbaceous vegetation and soils in mesic grassland
Get PDFLand degradation is widespread in communal rangelands in the grassland biome of South Africa, and often attributed to overstocking and lack of coordinated management. Excessive pressure on the herbaceous component has contributed to the uncontrolled spread of opportunistic invasive alien woody species e.g. Acacia mearnsii in many degraded areas, resulting in significant loss of ecosystem service capacity, along with soil and land productivity. Short-duration overnight kraaling has been suggested as a tool for restoring degraded rangelands. Recent studies in semi-arid savannas and shrublands have reported increased grass cover, soil nutrients and palatability and concluded that short-duration kraaling is a low-cost and effective way of restoring degraded rangelands using livestock. However, the response of different plant functional types and communities to such intense livestock impact may vary depending on local context. This study used twelve paired kraal and control sites to investigate the effects of short-duration (7-24 days) overnight kraaling of livestock on herbaceous vegetation and soils in a mesic grassland. The study area is generally considered to be overgrazed but has considerable variation in grass composition and basal cover. Sites included relatively intact natural grassland and sites where wattle infestations had been cleared and where mostly bare ground remained. I tested the hypotheses that overnight kraaling would result in (1) increased basal cover due to introduction of grass seed and stimulation of germination through hoof action, (2) increased infiltration due to hoof action, and (3) increased soil nutrients and organic matter due to dung and urine deposition. I also hypothesized that factors such as a site’s initial grass cover, its slope, the occurrence and amount of rainfall before and during kraaling, and the kraaling intensity (number of livestock and duration of the kraaling event) would influence the magnitude and direction of the kraaling effect. The effect of kraaling on vegetation was strongly dependent on initial condition. Kraaling increased basal cover of grasses when sites had low initial basal cover, but decreased basal cover if initial values were over 50%. Infiltration increased if kraaling took place during or after rain but decreased if kraaling took place when soils were dry. Kraaling increased soil P and K. In mesic grasslands, short-duration overnight kraaling is promising as a tool for rehabilitating degraded sites but should be avoided where the grass sward is relatively intact. I recommend that the suitability of kraaling be further evaluated per vegetation type and local context.Thesis (MSc) -- Faculty of Science, Botany, 202
The moderating influence of socioemotional wealth on the innovation choices and outputs of South African family businesses
Get PDFThe global impact of family businesses is increasing in a significant manner. The importance of family businesses has been recognised by academic institutions through the establishment of family business research centres and academic programmes for family businesses, as well as practitioner-oriented journals in family business studies. In most developed and developing market economies, family businesses have been projected as one of the primary forms of private enterprise that play an important role in both national and global economies, including South Africa. In other words, in the global innovation context, family businesses are considered to be the backbone of economic development. Given the importance of innovation to family businesses in contributing to economic growth and sustainability across generations, as well as the limited research that has been conducted on South African family businesses and innovation, the primary objective of this research was to investigate the relationship of selected drivers of innovation and Innovation outputs in South-African family businesses, as well as how the family, through its Socioemotional wealth, moderates the relationships between the drivers of innovation and Innovation outputs. This study uses the socioemotional wealth (SEW) and the resource-based theory (RBV) as the basis of its theoretical orientation. The following drivers of innovation were identified during the literature review (independent variable), namely: Financial capital, Human capital and leadership, Social capital, Learning orientation, Entrepreneurial orientation, Market orientation, Organisational culture, and Knowledge management as having an impact on Innovation outputs (dependent variable). In addition, Socioemotional wealth (SEW) was hypothesised as having a moderating influence on the relationships between the drivers of innovation and Innovation ouptuts. Four demographic variables (Size of the business, Age of the business, Generation of the family and Industry of operation) were identified as having a potential influence on the hypothesised relationships. Each of the constructs were clearly defined and then operationalised. Operationalisation was done by using reliable and valid items sourced from tested vii measuring instruments used in previous studies, as well as a number of self-generated items based on secondary sources. A structured questionnaire was made available online to respondents identified by means of the convenience snowball sampling technique, and data was collected from 331 family businesses in South Africa. The usable questionnaires were subjected to various data analyses techniques. Confirmatory Factor Analyses (CFA) were performed on each factor that confirms the factor structures by using various goodness-of-fit indices. Subsequent to the CFAs, the validity and reliability of the measuring instrument was assessed. As a result of these analyses, three new independent variables emerged as drivers of Innovation outputs in South African family businesses, namely: Funding of research and innovation, Financial, human and social capital resources, and Shared business vision, resources information and knowledge. In addition the SEW construct revealed two dimensions as dependant variables, namely: Family influence, control and commitment and Business reputation and commitment. The reliability of the measuring instrument was evaluated using Cronbach’s alpha coefficients, while the assessment of validity involved calculations of the average variance extracted (AVE) estimates and squared correlations between constructs. Structural Equation Modelling (SEM) was the main statistical procedure used to test the significance of the relationships hypothesised between the various independent, moderating and dependent variables. The main finding of the study reveals that there is a significant positive relationship between Financial, human and social capital resources, and Innovation outputs. There is also a significant positive relationship between Shared business vision, resources, information and knowledge and Innovation outputs. Furthermore, Family influence, control and commitment positively moderates the relationship between Shared business vision, resources, information and knowledge and Innovation outputs. while Business reputation and succession positively moderates the relationship between Financial, human, social capital resources, and Innovation outputs. Finally, Business reputation and succession positively moderates the relationship between Shared business vision, resources, information and knowledge viii and Innovation outputs. Concerning the selected demographic variables, this study found that Age of the business has a significant influence on Innovation outputs. This study makes several theoretical and practical contributions. This study is the first of its kind that investigates the relationship between the drivers of innovation and Innovation outputs of South African family businesses. Second, this study is the first to investigate how the family, through its Socioemotional wealth, moderates the relationships between the drivers of innovation and Innovation outputs of South African family businesses. Having a better understanding of how and when the family system impacts the innovation decisions in the family business is important because it helps researchers understand the differences between family businesses (i.e. family firm heterogeneity) and non-family businesses. Third, the findings indicated that the adaptation of the SEW and RBV theories was accurate in understanding how the family, through its socioemotional wealth, influences innovation decisions. Fourth, concerning the selected demographic variables, this study found that Age of the business has a significant influence on Innovation outputs. This finding is another valuable contribution to the literature on innovation, given the inconsistent and sometimes inconclusive findings concerning the relationship between age of the business and innovation activities. The study's final theoretical contribution is the development of a measurement tool that accurately assesses the drivers of innovation and innovation outputs and the influence of the five dimensions of socioemotional wealth. Other family business researchers, business mentors and or family business owners themselves can use this measurement tool to assess and monitor factors that have an impact on innovation activities inside their businesses. Practically, this study makes several suggestions on how family business owners and managers could improve the Innovation outputs of their businesses and become aware of how the family could influence the innovation choices and decisions made in the business.Thesis (PhD) -- Faculty of Faculty of Business and Economic Sciences, 202
The role of trade unions in organisational change in South African organisations
Get PDFOrganisations of the 21st century face a plethora of changes due to globalisation, a world referred to as volatile, uncertain, complex and ambiguous (VUCA). Organisations must consider pertinent stakeholders, specifically employees, and by representation, trade unions, during organisational change attempts. The study has explored the role of trade unions during organisational change in South African organisations. A literature review was conducted, which explored, amongst others, factors driving change, organisational change management models, the labour relations landscape in South Africa and the role of trade unions in organisational change. The empirical study included semi-structured interviews and a survey with a questionnaire. An exploratory sequential mixed methods research design was followed, with semi-structured interviews conducted with trade union representatives and human resource/employment relations managers. Thereafter, an online self-administered survey was conducted focusing on employees. A non-probability judgement design was employed in sampling the participants for the qualitative approach, and five (N = 5) HR/employment relations managers and six (N = 6) trade union representatives were interviewed. Random sampling was employed for the quantitative component and 74 questionnaires were completed. The interviews were thematically analysed while for the survey, exploratory factor and correlation analysis were used. The factor analysis extracted three factors: Before Change; During Change; and After Change. Based on the results recommendations for senior management, HR/ER managers; and for trade unions were presented. The recommendations include that organisations use the framework as a guide to involve trade unions. Trade unions and their representatives need to be acknowledged as important stakeholders before change is introduced. Knowledge of labour law is essential and a culture of open communication must be evident before, during and after change. Trade unions should organise conferences (Indabas) to reorientate and reskill themselves about their role during organisational change within South African organisations. The main contribution of the study is that HR/ER managers and trade union representatives should utilise the framework developed in this study to advance best practices in respect of the role of trade unions in organisational change in the South African context.Thesis (Ma) --Faculty of Faculty of Business and Economic Sciences, 202
A critical analysis of the criteria applied in South Africa to distinguish an independent contractor from an employee for income tax purposes
Get PDFThe study set out to critically analyse the criteria used by South Africa to determine the distinction between independent contractors and employees. Comparisons are also drawn with the criteria used in the United Kingdom(UK) and New Zealand (NZ) to assess whether there are new ideas that can be drawn from these and help improve the criteria used in South Africa. This was motivated by the ongoing debates around this issue and the desire to make a contribution that might bring some new insights and clarity. Under South African tax legislation employers are only obliged to deduct income tax from persons identified as employees while on the other hand, they cannot deduct tax contributions from the money paid to independent contractors for services rendered. Furthermore, there is no statutory definition for the term “independent contractor” in the Income Tax Act of South Africa nor in the country’s labour legislation. The definition of this term has largely been established by the labour courts in instances where disputes have arisen around these matters. Using a doctrinal research method (including a comparative legal research), which is a qualitative research approach, articles, statutes, judgements, explanatory memoranda, and policy documents on the subject under investigation were analysed. It is submitted that the criteria used in the two countries used in the comparison are similar to the ones used in South Africa, with some variations. All three countries use similar tests to make their determinations and a survey of the UK and NZ’s case law indicates that the most preferred criteria are the multifactoral approach to determine the true nature of the relationship between employers and their employees. This approach has been found to be more flexible which allows it to accommodate the changes that are occurring in the world of work. In the South African context, the labour court has adopted a substance-over-form approach in making their determinations, arguing that the nature of the working relationship between employer and employee is a more important indicator than the mere contents of a written contract. The labour court has also used labour legislation mainly to assist in the interpretation of the distinction between independent contractors and employees. The study established that the criteria used in the UK is a bit more complex because workers are put in three different categories and the definition of employee is not 4 uniform in all the available statutes. In New Zealand the multiple factor approach is preferred just like in South Africa. In conclusion is submitted that the study established that there is nothing, other than the UK’s Mutuality of Obligation Test, that would assist in further clarifying the criteria used to classify employees or independent contractors in South AfricaThesis (MA) -- Faculty of Faculty of Business and Economic Sciences, 202
Innovation in ecological restoration techniques: Enhancing Portulacaria afra survivorship in degraded arid thicket
Get PDFThe Albany Thicket Biome has undergone extensive degradation over the past century, particularly from overstocking of livestock in the arid types of thicket. The degradation of the biome, coupled with little to no natural recovery, prompted the South African Government to implement the Subtropical Thicket Restoration Programme (STRP) in the early 2000s to rehabilitate degraded thicket using unrooted Portulacaria afra truncheons. The STRP also sought to create job opportunities, bring about social upliftment, promote biodiversity conservation and incentivise farmers and landowners in the region to promote carbon trading and farming of P. afra using carbon credits. However, the survivorship of P. afra planted using the STRP planting protocol has been less than ⁓30% because they are planted in degraded areas, where the truncheons are subjected to harsh biophysical conditions such as hard, capped soil, high soil temperatures, drought and herbivory. The aim of this study, therefore, was to improve the survivorship of P. afra planted in degraded thicket to at least 30%, using modified planting methods. In this study, four treatments were applied in 210 pondings (or micro-dams), each with P. afra planted in them (the first three treatments used rooted cuttings). The first treatment involved watering regimes where pondings were watered at varying frequencies. The second treatment involved planting companion species alongside P. afra while the third treatment involved planting P. afra underneath a nurse canopy. In the fourth treatment, unrooted P. afra truncheons were planted inside pondings. The mean survivorship of the P. afra cuttings was assessed 18 months after planting. The watering regime treatments, including the control, all yielded a survivorship of over 75%, with the significantly highest levels of survivorship being displayed in the weekly watering treatment (90.9 ± 6.8%) (p < 0.01). The companion plant treatment also produced a high mean survivorship of P. afra (94.9 ± 3.6%), significantly higher than that of the nurse plants (87.5 ± 6.3%) (p < 0.01). Among the unrooted truncheons it was found that untreated truncheons had the highest survivorship (76.2 ± 17.6%), with the lowest mean being found in truncheons that were both pruned and scarified (70.8 ± 20.8%), suggesting that this treatment, out of all of them, is the least successful under the prevailing environmental conditions in the study area. However, there was no significant differences among the unrooted truncheon treatments and their respective survivorship values to further substantiate this assertion (p = 0.26). Findings in this study also suggest that planting P. afra cuttings under a nurse plant was ideal for P. afra survivorship due to the nurse plant’s ability to ameliorate the microclimate under which the cuttings can establish and grow. Despite the soil under the nurse canopy having a significantly lower mean soil water potential (-160.9 ± 200.5 kPa), compared to the open areas (-73.4 ± 55.7 kPa) (p = 0.04), the pondings under the nurse canopy still had a lower mean soil temperature (31.4 ± 5.25°C) than the treatments in the open areas (38.5 ± 2.7°C), during the harsh midday sun. These favourable characteristics are reflected in the P. afra cuttings under a nurse canopy having a higher chlorophyll fluorescence (0.76 ± 0.06). compared to those planted in open areas (0.73 ± 0.13), suggesting that the P. afra cuttings in the former treatment had a higher photosynthetic efficiency compared to those in the latter, despite there being no statistically significant difference in chlorophyll fluorescence between the treatments (p = 0.14). Although these findings suggest that applying these modifications to planting P. afra, having achieved its objective of increasing survivorship to well over 50%, is likely to produce favourable results not only in overall survivorship, but also in fast-tracking arid thicket rehabilitation and restoration, further research on these rehabilitation techniques and their effectiveness is required. Furthermore, the downside to these treatments is that they are costly and time consuming, which puts the feasibility of large-scale programmes using these applications into question. Further investigation is required to determine ways in which the cost-effectiveness of these applications can be enhanced.Thesis (MSc) -- Faculty of Science, Environmental Science, 202
Species diversity and distribution patterns of three freshwater fish genera in southern Africa
No full textAccess restricted. Expected release in 2025.Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 202
Gender, informality and urban livelihoods: eamining the livelihood strategies adopted by Black female street vendors in Makhanda, Eastern Cape
Get PDFThis study sought to examine livelihood strategies adopted by black female street vendors in Makhanda, Eastern Cape. The street vending activities that were undertaken by the research participants included selling: cooked foods, fresh fruit and vegetables, eggs, and beauty products. This study used the Sustainable Livelihood Approach (SLA) to examine the livelihood strategies of black female street vendors in Makhanda. The SL approach was chosen as an ideal framework for a study of this nature as it holistically and traditionally focuses on vulnerable population groups around the world. More importantly, the SLA gives agency to these vulnerable groups, as it prioritizes their innovative techniques in mobilizing diverse assets at their disposal in order to survive. The study is, therefore, ideal as it also gives agency to selected black female street vendors by examining how they utilized diverse assets at their disposal to sustain their livelihoods. This study seeks to contribute to the ongoing debate on urban livelihoods and the informal economy in South Africa, focusing particularly on the different methods or strategies employed by black female street vendors to enhance the sustainability of street vending as a livelihood. Due to the nature of this study, which seeks to capture the lived experiences of the selected black female street vendors in Makhanda, qualitative research methodologies were used to collect and analyse data. This study proved street vending to be a survival strategy that is used by black unskilled women in pursuit of livelihoods. It argues that, faced with the socio-economic realities associated with high unemployment, street vending can be used by many to best support their households. When it comes to livelihood strategies, this study found that, livelihood diversification is the most common livelihood strategy adopted by street vendors in Makhanda, with the only difference being the type of diversification adopted. Two forms of livelihood diversification strategies were identified in this study, and these included: product diversification and income diversification. The conclusion drawn from the findings argues that the selected street vendors in Makhanda strategically used different assets accessible to them to enhance and sustain their livelihoods. The study found that despite the different structural challenges faced by street vendors in Makhanda, the selected black female street vendors are able to meet their livelihood outcomes and support their families through engaging in street vending.Thesis (MSocSci) -- Faculty of Humanities, Sociology, 202