The Electric and Electronic Engineering Department at Stellenbosch University has an ongoing programme of high-altitude balloon (HAB) missions to conduct experiments in near-space conditions. The use of HAB payloads provides many of the same benefits as a low Earth orbit satellite for a fraction of the cost.
As the interest in studying cetaceans’ sounds increases, so has the motivation to develop different automated sound detection and classification methods. One such technique is passive acoustic monitoring (PAM) which was discussed in our previous post. PAM is used extensively to study cetaceans’ sounds over a predetermined period to understand their daily activities within their ecosystem. However, when using PAM, the collected sound datasets are usually large and impractical to manually analyse and detect.
The Department of Science and Technology’s Marine Research Plan focuses on understanding the role of biodiversity in maintaining ecosystems’ functionality, the relationships between human pressures and ecosystems, and the impact of Global Change on marine ecosystems. The Research Plan identified specific research themes including oceans and marine ecosystems under global change, ecosystems, biodiversity and biodiscovery, and coastal and marine resources, society and development. Investigating and developing signal processing algorithms for underwater acoustic signals to detect, classify and track cetaceans forms part of the third theme of the Plan. There are some challenges to monitoring cetacean populations Addressing the challenges Conclusion A good representation of overall marine ecosystem health is evident from the abundance and state of marine mammal populations. Nevertheless, various factors including climate change and human activities can affect these ecosystems. However, the effective monitoring and management of marine living resources – where these living organisms inhabit a vast, mainly inaccessible and hostile environment – requires innovation and the use of the best available technologies and methods.
The soundscapes of our oceans have undergone substantial changes as a result of human anthropogenic activities. This, in turn, threatens the existence of ocean mammals such as the Bryde’s whale, as they use sound to navigate, communicate, avoid predators, recognise prey for survival and function properly within their ecosystem. Anthropogenic activities include shipping, offshore exploration, geophysical seismic surveys, and naval sonar operations. These activities have been detrimental to marine fauna and caused, amongst others, physical injury, physiological dysfunction, and behavioural modification. Overall, it caused a decrease in reproduction rate. Nevertheless, very little information regarding the population dynamics and taxonomic status of Bryde’s whales exists. Recent research strongly suggests that the two ecotypes, namely the resident inshore Bryde’s whale and the seasonal offshore Bryde’s whale, can be split at a species level. This can have far-reaching implications, putting the inshore Bryde’s whale species at a real and substantial risk of extinction.
Our blog series on solar sail technology commenced with a brief overview and introduction to solar sailing as well as the controlling mechanisms of sailcrafts followed by an investigation of the deployment of a spinning solar sail, its theoretical dynamics and its practical aspects. In this final post, we look more closely at some of the different sail satellites that have been deployed successfully. Interplanetary Kite-craft Accelerated by Radiation of the Sun (IKAROS) NanoSail-D2 and FeatherSail Cosmos-1 and LightSail-1 Lightsail 2 The effect of solar radiation pressure was well known and was even used during the Mariner 10 mission. The solar radiation pressure was used to create a windmill torque to maintain the angular rate around its roll axis. The IKAROS satellite from JAXA was the only successful mission dedicated to solar sailing in the past. There are, however, other successful satellites that deploy drag sails including the NanoSail-D2 from NASA and LightSail. There are also several new sail satellites (solar sail and drag sail) that are close to being completed and will be launched soon.
1. Introduction – What is confocal microscopy and how does it work? Confocal microscopy is a leading imaging tool used in molecular life sciences with which to render detailed high-resolution three-dimensional data sets. It is instrumental in biological analysis and research where structures of interest are labelled using fluorescent probes. Typically, the three-dimensional data is rendered as a projection onto a two-dimensional display. However, this could lead to uncertainty in the visual interpretation of the sample’s structures of interest. Besides, analysis and region of interest (ROI) selection are also most commonly performed two-dimensionally which may inadvertently lead to either the exclusion of relevant or the inclusion of irrelevant data points. This, in turn, could affect the accuracy of the analysis.
The notion of using the photons emitted from the sun for propulsion in space is not novel. In fact, as early as 1610, Johannes Kepler noticed the potential of this when he pointed out that “comet trails always pointed away from the sun and theorised that the cause may be solar radiation pressure”. Our previous article provided a brief overview and introduction to solar sailing as well as the controlling mechanisms of sailcrafts. In this article, we investigate the deployment of a spinning solar sail with an understanding of both the theoretical dynamics and practical aspects thereof which forms the focus of the original research listed below. The categories of sailcraft: spin and three-axis stabilised Sail structures and deployment Cubesat solar sail 3-axis stabilization using panel translation and magnetic torquing Conclusion
Increased Global emissions resulted in stronger efforts to reduce emissions in order to stabilise the global warming benchmark at 1.5°C. This means that in order to meet the 2030 emissions targets, G20 countries will have to maximise their efforts in 2020 and “and significantly bolster mitigation, adaptation, and finance measures over the next decade”. In light of the above and closer to home, it has been noted that South Africa has the highest emission intensity in the G20 group of industrialised and developing countries. For the country to meet reach its global warming target, it will have to reduce emissions by 32% in the next 10 years. However, the country’s inconsistent contribution is driven by coal-dependent and crisis-riddled national electricity utility, Eskom, which is compromising South Africa’s commitment to slow global warming.
Interest in solar sailing – a revolutionary way to propel spacecraft through space – has piqued in recent years which lead to significant research and resources being contributed to developing it as well as developing similar and supporting technologies. An example of solar sailing in motion is the Planetary Society’s LightSail 2 mission. In this article we cover: A brief introduction to solar sailing The controlling mechanisms of sailcrafts Conclusion
Traditionally, biological visualisation was limited to two-dimensional displays only. Until recently, using three-dimensional displays for quantitative signal assessment, including precise signal selection, processing of multiple signals and determining their spatial relationship to one another has received fairly little attention. However, recent developments in the virtual reality (VR) arena have seen the development and use of lightweight headsets, offering high resolution, low latency head tracking, and a large field of view. These developments and innovation make VR an attractive form of technology to use in biological data visualisation. Biological data visualisation as a branch of bioinformatics entails the application of computer graphics, scientific visualisation, and information visualisation to different areas of the life sciences. Software tools that can be used for visualising biological data include simple, standalone programs and complex, integrated systems. It allows immersive three-dimensional visualisation, compared to a three-dimensional rendering on a two-dimensional display. Since the visualisations are based on a true three-dimensional awareness of the sample, they not only offer a clear representation but also a more intuitive process of interaction which can ultimately aid the scientific investigation and discovery process.
