ResearchSpace

Communities in ResearchSpace

Welcome to ResearchSpace, the institutional repository of the CSIR. ResearchSpace is an open access electronic archive collecting, preserving and distributing scholarly digital materials created by the CSIR.

Recent Submissions

Item

Material selection and optimisation of a 3D-printed indoor aerial robotics platform

(2024-12) De Ronde, Willis; Botha, Natasha; Van Eden, Beatrice; Tshabalala, Lerato C

Both aerial robotic platforms and additive manufacturing (AM) have become more affordable to consumers. Indoor aerial robotic platforms are typically small and lightweight, while AM is renowned for creating small, high-strength prototypes and components. This paper discusses the material selection and structural optimisation of a 3D-printed indoor aerial robotic platform. Three commonly used AM materials were compared using finite element analysis (FEA): acrylonitrile butadiene styrene (ABS), polyethylene terephthalate glycol (PETG), and Nylon. It was found that Nylon offered the best performance in terms of the strength-to-weight ratio. The aerial robotic frame was optimised using an iterative design approach and previous knowledge with regards to the breaks observed during flight crashes. A dynamic FEA was performed to simulate a drop test from a height of one meter to compare the optimised design with the previous frame design. It was found that the improvements in the redesign have led to a 13.67 % decrease in weight and a 11.78 % decrease stress of the aerial robotic frame. This not only demonstrates the effectiveness of design optimisation, but also highlights the commitment to producing more efficient, reliable and sustainable designs.

Item

Designing school rainwater harvesting systems in water-scarce developing countries

(Routledge, 2024) Gibberd, Jeremy T; Adler, I; Adeyeye, K; Bello-Dambatta, A; Takacs, B

Many schools in water-scarce developing countries have insufficient and unreliable water supplies. This is being exacerbated by climate change and ageing and poorly maintained water infrastructure. A lack of clean water increases the risks of diarrhoeal disease and concerns about health can result in school closures, affecting education outcomes as valuable teaching and learning time is lost. In these situations, rainwater harvesting systems can provide an alternative, clean water supply that enables schools to continue to operate safely. However, there is limited research and guidance on school rainwater harvesting systems. In addition, there are also misconceptions about rainwater harvesting. These include that rainwater harvesting systems cannot provide sufficient water to meet needs, the water produced is dirty and the systems are unaffordable. This chapter addresses this context by showing how rainwater harvesting can provide sufficient and affordable water supplies to schools in water-scarce areas. It may be of interest to school governing bodies, teachers, design professionals and government officials who want to develop rainwater harvesting systems in schools.

Item

A government sustainable building rating tool?

(2024-07) Gibberd, Jeremy T

Some countries have significant public building backlogs. Schools, colleges, clinics, and hospitals still need to be built and existing infrastructure needs to be updated and refurbished. In addressing backlogs, there is the prospect of developing more sustainable buildings and infrastructure. However, often this opportunity is not taken, and the design and construction of public buildings continue to follow conventional unsustainable approaches. Reasons for this include the lack of a suitable sustainable building rating tool that aligns with government priorities. To address this gap, this study explores development a Government Sustainable Building Rating Tool (GSBRT). It investigates this for South Africa, a country with large public building backlogs. Government policy is analysed to establish the key development priorities and translate these into building performance criteria. These criteria are compared with criteria from an existing green building rating tool, to determine alignment. The study finds that while there is some overlap, there are also significant differences and that the conventional green building rating tool does not cater for some government sustainable development priorities. Recommendations are made for further research and development of a GSBRT as a means of addressing sustainability in government buildings.

Item

Effects of heat treatment on the properties of arc melted AlCuFeNiSi0.4 and AlCuFeNiTi0.2 high entropy alloys for engineering applications

(2024-12) Adeyoye, A; Popoola, P; Mathe, Ntombizodwa R; Popoola, O; Dada, M; Dhliwayo, N

In this study, AlCuFeNiSi0.4 and AlCuFeNiTi0.2 high entropy alloys (HEAs) were synthesized using arc melting. The as-cast alloys were heat treated at 750 °C for 4hrs then quenched in water and oil and aged for 6hrs to examine the influence of the quenching media (water and oil) on the microstructural, nanomechanical, corrosion and wear characteristics of the alloys. The XRD results revealed that both alloys had BCC phase and FCC phase structures, where Ti and Al were the BCC stabilizers and Cu and Ni acted as FCC stabilizers. The excellent combination of hardness and elastic modulus of both alloys quenched in water shows that ageing can improve the properties of the alloys. The alloys quenched in water after ageing offered improved properties compared to those quenched in oil for both alloys. The wear resistance was higher in AlCuFeNiSi0.4 than inAlCuFeNiTi0.2 attributed to the strengthening mechanism of the alloy. Electrochemical tests also showed that the AlCuFeNiSi0.4 alloy composition was more corrosion resistant and easier to passivate in 3.5% NaCl. The combined action of the elements in the HEA composition produced surface oxide layers that were more stable and resistant to corrosion. Hence, the heated treated Si0.4 HEA derivative has the potential to be used as materials in wider corrosive environments in the energy industry.

Item

Developments in localized surface plasmon resonance

(2024-12) Mcoyi, Michael P; Mpofu, Kelvin T; Sekhwama, Masindi; Mthunzi-Kufa, Patience

Localized surface plasmon resonance (LSPR) is a nanoscale phenomenon associated with noble metal nanostructures that has long been studied and has gained considerable interest in recent years. These resonances produce sharp spectral absorption and scattering peaks, along with strong electromagnetic near-field enhancements. Over the past decade, advancements in the fabrication of noble metal nanostructures have propelled significant developments in various scientific and technological aspects of LSPR. One notable application is the detection of molecular interactions near the nanoparticle surface, observable through shifts in the LSPR spectral peak. This document provides an overview of this sensing strategy. Given the broad and expanding scope of this topic, it is impossible to cover every aspect comprehensively in this review. However, we aim to outline major research efforts within the field and review a diverse array of relevant literature. We will provide a detailed summary of the physical principles underlying LSPR sensing and address some existing inconsistencies in the nomenclature used. Our discussion will primarily focus on LSPR sensors that employ metal nanoparticles, rather than on those utilizing extended, fabricated structures. We will concentrate on sensors where LSPR acts as the primary mode of signal transduction, excluding hybrid strategies like those combining LSPR with fluorescence. Additionally, our examination of biological LSPR sensors will largely pertain to label-free detection methods, rather than those that use metal nanoparticles as labels or as means to enhance the efficacy of a label. In the subsequent section of this review, we delve into the analytical theory underpinning LSPR, exploring its physical origins and its dependency on the material properties of noble metals and the surrounding refractive index. We will discuss the behavior of both spherical and spheroidal particles and elaborate on how the LSPR response varies with particle aspect ratio. Further, we detail the fundamentals of nanoparticle-based LSPR sensing. This includes an exploration of single-particle and ensemble measurements and a comparative analysis of scattering, absorption, and extinction phenomena. The discussion will extend to how these principles are applied in practical sensing scenarios, highlighting the key experimental approaches and measurement techniques.