1834 research outputs found
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Optimisation of multi-scale ventilated package design for next-generation cold chain strategies of horticulture produce
No full textCorrugated fibreboard boxes (cartons) are used extensively in the cold chain to
transport fresh produce from growers to consumers. These ventilated packaging
systems have multi-scale structures and should facilitate suitable cooling of produce
to preserve quality, protect against mechanical damage and enable efficient
handling and transport. However, current designs often do not incorporate these
factors and improved designs have been identified as part of new strategies to
reduce postharvest losses and enhance overall cold chain efficiency.
The aim of this thesis was to develop improved fresh produce packaging designs
through the use of a novel multi-parameter evaluation approach, within the scope
of a multi-scaled packaging system. To this end, computational fluid dynamics
(CFD) models and experimental box compression tests were used to evaluate new
packaging designs, to quantify spatio-temporal moisture distributions in cartons
during shipping and to increase packing densities in refrigerated freight containers
(RFC).
Three new vent hole configurations were proposed and compared against an
existing carton used for handling pome fruit. Results showed that the presence of
trays reduced cooling efficiency by 31% in the standard commercial design.
Conversely, the use of the newly proposed vent designs considerably improved both
cooling efficiency and cooling uniformity by 48% and 79%, respectively.
Next, the effect of vent hole area and board material was investigated. Results
demonstrated that significant improvements in both cooling efficiency and carton
strength are possible, using alternative vent hole designs. Additionally, a significant
interaction, with respect to mechanical strength, was observed between board
material properties (board type) and the vent hole design. This finding indicates that
high humidity conditions (i.e. refrigerated transport) can substantially influence the
expected mode of failure in cartons (mechanical performance).
Furthermore, a CFD model was developed to predict spatio-temporal moisture
distribution in cartons loaded in a RFC. The study of a standard shipping scenario
showed that moisture gradients were relatively small, indicating that mechanosorptive
creep is likely not a major factor in this case. However, larger gradients are
expected during less desirable conditions. These findings can be used as baseline
conditioning treatments for future carton compression protocols.
Lastly, two unique packaging system strategies were proposed and evaluated for
cooling efficiency. Although both showed generally improved performance, the
“Tes” design increased packing density by 12% and forced-air cooling efficiency
by 29%, compared to standard designs. Findings also showed improvements in vent
hole design for vertical flow (RFC) are still possible.
Overall, research reported in this thesis contributes towards the development of a
more optimal ventilated packaging design for use in the fresh produce cold chain.
Significant advancements were also made with respect to the implementation of a
multi-parameter evaluation approach, which should be further extended to future
assessments of fresh produce supply chains both in academia and in commercial
practice. Finally, significant knowledge gaps were revealed with respect to the
mechanical performance of cartons under high humidity conditions. Future studies
should therefore concentrate on the development of new predictive approaches to
better assess the integrated performance of cartons under cold chain conditions.National Research Foundatio
Piercing the corporate veil : a critical analysis of section 20(9) of the companies act 71 of 2008
No full textOnce a company is incorporated it becomes a juristic entity, distinct and separate from its incorporators. Thus, the company bears its own liabilities. However, section 20(9) of the Companies Act 71 of 2008 grants the courts the discretion to disregard the separate legal personality of a company where there is unconscionable abuse of the juristic personality of the company. However, the challenge is that the section fails to define what constitutes ‘‘unconscionable abuse’’. This research thus investigated what constitutes unconscionable abuse of the juristic personality of the company as the ground for piercing the corporate veil. Simply put, this research identified the circumstances under which the corporate veil may be pierced, given the confounding provisions of section 20(9). In unravelling the problems posed by the said section, the researcher employed a combination of doctrinal legal research methodology and comparative research methodology which involve the scrutiny of ‘black letter of the law’ and the laws of other jurisdictions. The result from this extensive inquiry is that the term ‘unconscionable abuse’ is a legislative derivate from the various terms used by the courts at common law to justify the disregarding of the separate legal personality of the corporate entity. Therefore, the inescapable conclusion reached is that just as those terms used at common law are confounding, so shall this legislative innovation. Therefore, in order to resolve this problem each matter should be dealt with based on its peculiar facts.National Research Foundatio
Science/Nanotechnology does not belong to scientists but to society, hence a need for effective science communication by scientists
No full textNRF awards 2017 video
No full textThe annual NRF Awards recognise and celebrate South African research excellence. The awards presented to researchers are in two categories, the ratings linked awards and special recognition awards. The rating linked awards are given to those who have qualified for an A or P rating, as evaluated through the peer review based NRF rating system. The special recognition awards provide a platform to honour researchers for career achievements and contributions to knowledge creation and dissemination, as well as capacity development and transformation
The Aardvark as an ecological engineer in the Eastern Karoo: dig patterns and emergent processes
No full textSpecies which play particularly important roles in ecosystem patterns and processes are recognised as keystone species or ecosystem engineers. The conservation of these species is critical for the maintenance of the ecological role they play in ecosystem function. The aardvark, Orycteropus afer, is known to play a role in biopedturbation through digging for refuges and for prey, and as a consequence of these digging activities is expected to serve the role of an ecosystem engineer and keystone species. This study aimed to describe and quantify the ecological patterns and processes driven by the aardvark through their digging activities, within the eastern Karoo, and thereby evaluate the significance of aardvarks as ecosystem engineers and keystone species in a semi-arid environment. The landscape pattern (dig abundance and distribution) and soil displacement of aardvark forage and refuge digs in a semi-arid Karoo landscape, as well as the ecological processes (generating fertile, seed retention hotspots) driven by aardvark forage digs was measured. Refuge digs occurred in the highest densities in areas characterised by a specific suite of soil, vegetation and elevation features, while forage digs occurred in high abundance in most habitats measured, and were likely driven by prey availability. Forage digs served as litter and seed retention hotspots, with accelerated decomposition rates of litter as a function of increased soil moisture in digs. The functional processes (i.e. resource capture, shelter for plants and animals, germination sites, soil aeration, organic turnover, mineralization rates, fertile soil displacement and transport) driven by aardvark digs are not restricted to refuge digs. Forage digs occurred in most habitats measured and their functional role is unique and perhaps greater across the landscape in comparison to refuge digs. The aardvark has a disproportionate effect in ecosystems, in terms of its refuge and forage digs relative to its abundance and therefore its role as a keystone species and ecosystem engineer is confirmed. Conservation and protection of this species is therefore essential to maintain its important role in ecosystem function.National Research Foundatio
Factors affecting green supply chain management (GSCM) initiatives : a case study at Cipla Medpro Manufacturing
No full textSustainability has become a critical issue for both society and businesses globally. With the increase of natural disasters and global issues such as water shortages, acid rain and climate change companies have started focusing on reducing their carbon footprint to ensure that the world’s natural resources are sustained for the foreseeable future.
Many international and local companies are now looking to incorporate green initiatives into key functional areas such as Supply Chain Management. This has given rise to Green Supply Chain Management which is the incorporation of sustainable initiatives into the supply chain of a company.
In the pharmaceutical industry the implementation of Green Supply Chain Management initiatives is a challenge, because of the complexity of their supply chain. Consequently, it is essential to determine what factors affect these initiatives in order to successfully implement and maintain Green Supply Chain Management initiatives.
In South Africa there are many other factors that pharmaceutical companies need to take into consideration before the implementation of Green Supply Chain Management. Some of these factors include high costs, lack of government support and pressure to lower prices. This makes it more difficult for companies such as Cipla Medpro Manufacturing to incorporate green initiatives into their supply chain. Some recommendations to overcoming these factors include the reduction of costs through better product design and the use of green technologies in order to reduce costs.
If the key factors affecting Green Supply Chain Management can be identified pharmaceutical companies can focus on overcoming these factors and utilise their resources more efficiently and effectively. This will improve the success rate of Green Supply Chain Management initiatives overall and make them a more attractive method to reduce their companies carbon footprint.National Research Foundatio
Identification and classification of micro-estuaries using selected abiotic and biotic characteristics along the Eastern Cape coast, South Africa
No full textMany of the larger estuaries along the South African coastline are highly degraded due to human impacts, highlighting the need to conserve pristine systems. There are approximately 100 micro-estuaries along our coastline which have not yet been identified or classified and hence their ecological functioning is unknown. The aim of this study was to identify and classify micro-estuaries along the Eastern Cape coast. Specific objectives of the study were to: 1) map the distribution of estuarine habitats in a selection of micro-estuaries and assess changes over time; 2) measure the physico-chemical characteristics of the micro-estuaries in the field; 3) investigate the distribution of vegetation, identify macrophyte species and habitat integrity and classify the micro-estuaries sampled using abiotic and botanical characteristics. A total of 30 systems were identified of which 10 were selected for sampling which took place seasonally (2015-2016). A relationship between open water surface area and short term rainfall was only evident in Cunge, Sandy Bottom and Ichabana. In the field it was observed that after heavy rainfall, open water surface area increased and mouth breaching occurred. Salinity was the only water column characteristic that showed differences; salinity increased in response to over wash events. Sand was dominant in all systems and there were no differences in sediment characteristics. A total of 8 macroalgal species, 16 estuarine macrophyte species, six freshwater species and 72 riparian plant species were found. Seed bank reserves were low in all systems despite them being vegetated. Only abiotic characteristics were used for classification using Principle Components Analysis since there were no botanical differences between systems. Micro-estuaries were larger (> 0.03 ha), had a higher salinity (oligohaline, mesohaline and polyhaline conditions) and a constant water body. Micro-outlets were smaller (< 0.03 ha), had a lower salinity (oligohaline conditions were most common) and showed periods of drying. Five micro-estuaries (Shelbertsstroom, Kwesani, Cunge, Mtwendwe and Mtendwe) and five micro-outlets (Stromatolite, Sandy Bottom, Ichabana, Palm Tree and Black Rock) were classified. This study has shown that the micro-estuaries along the Eastern Cape coast are pristine (i.e. intact riparian zone and catchment), untouched and highly dynamic systems (i.e. great variation in water surface area and mouth condition) highlighting their need for protection.National Research Foundatio