Conveners
Applied Physics
- phil ferrer (wits)
Applied Physics
- Freddie Vorster (Nelson Mandela University)
Applied Physics
- Ernest van Dyk (Mandela University)
Applied Physics
- Trevor Derry (University of the Witwatersrand)
Applied Physics
- Thulani Hlatshwayo (University of Pretoria)
Applied Physics
- Aletta Karsten (NMISA)
Applied Physics
- There are no conveners in this block
We considering the Euler equations in one dimension. The system is discretized in space using an arbitrarily high order Bernstein finite element scheme. In time, the equations are discretized using a high order implicit or explicit Runge-Kutta time stepper. To deal with shocks and spurious oscillations in the numerical solution, stabilization, in the form of algebraic flux correction is...
In ghost imaging, an object can be imaged by interrogating a photon that has not interacted with it. One of the entangled photons in a pair interacts with the object while the spatial distribution of the second photon is measured. Due to the correlations, the spatial properties of the non-interacting photon carries information about the object despite never having contact with it. An image of...
Data AcQuisition (DAQ) systems are highly susceptible to technological development due to the intricate relationship between their design and currently available hardware. As a result, they are required to continuously evolve alongside one another. This when coupled to the manner in which particle detectors such as ATLAS are required to evolve in order to accommodate ever-increasing...
The unequal access to reliable internet connectivity between urban and peri-urban areas remains an issue of concern in many developing countries, including South Africa. A major reason for this so-called 'digital divide' is the unequal distribution of fibre infrastructure, which is usually due to economic or geographic reasons. This could be mitigated through the deployment of Free Space...
The Vacuum Arc Thruster (VAT) is a simple electric propulsion system for small satellites, providing low thrust at moderate specific impulse. In this work the VAT is investigated as a plasma source for a high performance ion thruster. Spacecraft figures of merit are presented and the relevant literature is reviewed. Several inductive energy storage arc circuits were built and their electrical...
Wavefront sensing is a branch of metrology essential in applications ranging from microscopy, astronomy and optical manufacturing to laser design, free-space communication and ophthalmology. Dominating the industry are the ubiquitously used Shack-Hartmann sensors, which suffer from resolution versus acquisition rate trade offs; as well as inteferometric sensing, which has ...
Pairs of entangled photos are used to reconstruct an image in the application area known as quantum ghost imaging. It is the correlation between the photon pair that allows for the reconstruction of the image, as opposed to single photon detection. The entangled photons are spatially separated into two independent paths, one to illuminate the object and the other which is collected by a...
It is beneficial to construct a model that will aid in the development of ways to analyze a system qualitatively or quantitatively in any study. The goal of this research was to create a system that imitated physical adsorption on the surface of Metal Oxide gas sensors from the ground up. A mathematical expression was developed that relates time to the amount of adsorbed gas molecules. Python...
Long distance optical communication has long relied on the use of single mode optical fibres to transport information. This method is limited because only one mode may be used thus restricting the rate at which data can be transferred. Conversely, free space propagation can make use of multiple modes, allowing for a much greater rate of data transfer. The main obstacle to overcome in free...
Optical modal decomposition is a very well-known technique of expressing some arbitrary field as a linear superposition of spatial modes that form a complete and orthogonal basis, not unlike the reconstruction of some signal via a combination of sinusoidal functions with varying frequencies. The reconstruction of a field created out of a superposition of modes chosen from some pre-selected...
Naleli Jubert Matjelo1, Makhamisa Senekane2, Mhlambululi Mafu3, Sebota Mokeke1, Lerato Lerato4
1Department of Physics and Electronics, National University of Lesotho, Roma, Lesotho
2Institute for Intelligent Systems, University of Johannesburg, Johannesburg, South Africa
3Department of Physics and Astronomy, Botswana International University of Science and Technology, Palapye,...
Rechargeable sodium-ion batteries have attracted great attention for large-scale electric energy storage applications and smart grid owing to the abundance of Na resources and comparable performance with lithium-ion batteries. The use of organic electrode materials enables a sodium storage system with high energy/power density, metal-free, environmental friendliness, flexibility, lightweight,...
The fluid flow and temperature environment of the planned upgrade of the ATLAS inner Tracker is investigated by computational simulation in order to inform design and assure specifications are met. This is done using Computational Fluid Dynamics. The essence of the this approach is that fluid dynamics equations that would be analytically unsolvable for most cases can be approximated to a high...
Microcontroller units often are essential parts for experimental setups and automatic control. Since the simplifications of the programming platforms, the microcontrollers have become accessible to a large spectrum of researchers, also with limited knowledge of the microcontroller systems.
Over a plug and play philosophy, the simplification pertains to the software realisation since many...
Highly selective sensors that can sense at least two gases are necessary for less expensive, effective, and reliable monitoring of air quality. Conventionally, selectivity is achieved by improving sensor response towards selected target gas. This study suggests the use of materials with unique response switching to achieve selective sensing. Monoclinic β-Ga2O3 needle-like structures were...
Photovoltaic water pumping systems (PVWPS) are a promising solution to improve water accessnin isolated rural areas in developing countries. Each system must be carefully sized to satisfy local demand while being as affordable as possible. In order to design a successful and sustainable system, the knowledge of solar radiation and groundwater resources availability is crucial. There are...
Abstract
The prediction of solar irradiance for certain regions is of utmost importance in
guiding solar power conversion systems with a specific focus on design, modelling,
and operation. In addition, the selection of proper regions with sufficient solar
irradiance also plays a significant role for the decision-makers responsible for future
investment policies about green energy. The...
Over the past years, we have developed a unique receiver geometry which allows for efficient conversion of solar energy at elevated temperatures in a solar trough unit. Due to the directional nature of the cavity, where the opening is facing the parabolic mirror, the focal length of the mirror is unconventional, and required its own design. Further, the location of the focal plane in relation...
As the deployment of renewable energy increases, particularly Photovoltaic (PV), non-destructive techniques become more important for characterising the materials from the cell level to complete module level. Luminescence imaging is a non-destructive characterisation technique that allows for spatially resolved optoelectrical characterisation of cells. This paper presents the development of...
Perovskite based PV devices are gaining attention due to lower predicted overall costs and high efficiency. However, the commercial viability of this technology is dependent on long term reliability and stability. This technology is more sensitive to environmental conditions such as moisture and oxygen compared to conventional PV devices. Different encapsulation methods have been proposed as...
Bifacial photovoltaic (bPV) modules utilise light incident on both front and rear surfaces. This leads to enhanced power generation characterised by the bifaciality coefficients, which is the ratio of electrical characteristics between front and rear surfaces. The amount of light reflected from the surface underneath a tilted module is a major contributing factor to the rear irradiance-driven...
Medical physics has revolutionized how cancer is diagnosed and treated. From imaging to therapy, the principles of physics have shown the inseparable relationship with biological systems. One such example is Photodynamic Therapy (PDT), a therapeutic modality that uses light to kill cancer by means of a photochemical reaction that is initiated when a photosensitizer (PS) molecule absorbs a...
Modelling of clinical public health data in clinical spaces guided by principles of physics can produce safer environments. Understanding airborne transmission of viruses is essential considering the recent worldwide SARS-CoV-2 pandemic. More understanding can help define better public health strategies to adopt and to design public spaces in such a way that humanity is no longer vulnerable to...
Pharmaceutical industries produce a wide range of pollutants in the form of effluents that have a negative impact on environmental health, resulting in not only a significant economic loss but also a violation of the human right to clean and safe water. These wastes contain significant levels of volatile organic chemicals (VOC) (e.g., benzene, toluene, and ethylbenzene). A kind of biopolymer...
A Physics-Informed Neural Network (PINN) is a neural network that is constrained by laws of physics. The best-known type of PINN is a feedforward, fully connected neural network, or multi-layer perceptron, with a loss function that has a data term plus a term for the PDE that governs the physical system. Including physics knowledge that is additional to data reduces the solution space, which...
The non-destructive elemental analysis of materials is of interest to many industries, and fast neutron based techniques are of particular interest due to their sensitivity to low mass elements such as H, C and O. Neutron interactions are strongly energy dependent, and produce a variety of characteristic radiation signatures such as prompt and delayed gamma rays, or transmitted and scattered...
The benefit of proton therapy will only truly be realized once an experimental in-vivo dose verification system has been developed. The use of a Compton Camera (CC) allows detection of the secondary radiation, specifically Prompt Gammas (PG), produced at the location of the dose deposition. The UCT Polaris detector is composed of two separate stages with two CdZnTe positron-sensitive...
The Large Hadron Collider (LHC) has planned a series of upgrades leading to a High Luminosity LHC (HL-LHC), which would produce five times the nominal instantaneous luminosity of the LHC. The ATLAS Phase II upgrade in 2029, will accommodate the detector and data acquisition
system for the HL-LHC. The Tile Calorimeter on- and off-detector electronics will be completely replaced. This is...
Positron Emission Particle Tracking (PEPT) measures the trajectory of a freely moving radioactive tracer particle, and enables the non-invasive study of dynamic systems from engineering to medicine. PEPT performance is limited by the activity achievable in radiolabelling a suitable tracer particle, and the fixed geometry of conventional detector systems. In investigating phenomena on...
A significant challenge in low temperature thermometry is the accurate measurement of temperatures below 1 k. Nuclear Orientation (NO) is a non-electronic technique to measure ultra-low temperature accurately as opposed to traditional resistive thermometers. The NO method relies on the measurement of the alignment of the nuclear spin in a radioactive nucleus, where the temperature can be...
In nuclear power plants, concrete structures are exposed to high stresses, prolonged high temperatures, moisture and high levels of neutron and gamma-ray radiation. These conditions often cause the concrete to degrade and change in composition over time, particularly with respect to water content [1]. The shielding properties, and subsequent elemental composition, of existing concrete need to...
PEPT is a radioactive particle tracking method, based on the medical imaging technique of positron emission tomography. PEPT can track the movement of a positron-emitting tracer as it moves within a multiphase fluid. An example application is froth flotation, a mineral separation process which utilises gas bubbles to separate the solid minerals based on hydrophobicity. The dense suspension...
