Free space optical communication has proven to be an effective form of transmitting information over large distances. Structured light has proven to be a valuable tool in improving such channels but is quickly reaching its limits due to the distortions induced by atmospheric turbulence. It has been shown that certain shapes of light, the eigenmodes of turbulence, remain invariant to these...
Gas sensing is the detection of toxic gases in the environment/atmosphere for air quality and safety control. It iss based on the principle of transforming the gas adsorption effects on the surface of the active material into a detectable signal in terms of its changed electrical, optical, thermal, mechanical, magnetic (magnetization and spin), and piezoelectric properties. In this work, DFT+U...
This work reports the result of the comparison between calculated entrance skin dose (ESD) and measured entrance skin dose using thermo-luminescent dosimeter (TLD) in a teaching hospital in North Central, Nigeria. The exposure parameters and anthropometric characteristics of twenty (20) adult patients exposed to X-ray radiation at the Benue State University Teaching Hospital, Makurdi, North...
Natural polymers are now being considered for composite materials because of their biodegradability in comparison to synthetic polymers. Hence much of scientific research is directed toward unleashing unknown and technologically applicable properties of these organically derived materials. Resonance acoustic spectroscopy uses sound waves as a probing medium to trigger vibrations of an elastic...
The current global energy crisis is threatening sustainable development. In South Africa, the continuous increase in power outages (load shedding) is crippling the country's economic growth, as evidenced by the recently witnessed closure of several small businesses. An avalanche in implementing different renewable energy technologies has been witnessed, with several residential buildings and...
Comparison of A12O3 and Fe2O3 surfaces using First Principle method
P.M Dibakwana*^1, D.M Tshwane^3 , R. Modiba^2 and M.E ’Sithole^1, ,
1^Department of physics, Sefako Makgatho Health Sciences
University, Garankuwa, Pretoria, 0001
2^Future Manufacturing, Advanced Materials Engineering, Council of Scientific and Industrial Research, P.O Box 395 Pretoria 0001, South...
The Large Hadron Collider (LHC) has four main experiments along the ring. The ATLAS (A Toroidal LHC Apparatus) experiment along with the other three experiments enables the physicists to analyze collected data. The Large Hadron Collider needs to be upgraded to a High Luminosity Large Hadron Collider (HL-LHC) to account for the increase in luminosity and to enable physicists to explore...
The water pumping system in the agricultural sector is one of the major users of photovoltaic solar energy particularly in off-grid locations. For an optimal functioning of the system to be achieved, a real-life monitoring tool can provide the farmer or operator to be in-charge and be able to control the system remotely. In the current study, a monitoring the influence of meteorological...
The adsorption and interaction mechanisms of gaseous molecules on ZnO surfaces have received a substantial amount of attention recently as a direct result of the technical uses that they offer in gas sensing. The adsorption behaviour of molecules of NH3 and NO2 was examined using density functional theory on surfaces of undoped and M-doped ZnO (101) where (M = Ni, Co, and Cu). It was...
Biogas digester dimensions and materials of construction are important factors of consideration during the design and fabrication phase. &e aim of this study is to provide a detailed analysis of the design and fabrication of a 2.15 m3 pilot plastic biogas digester for biogas generation. To establish this, a design equation covering the volume of the digester, inlet and outlet chambers,...
With global threats to energy security, the need for diverse energy sources is becoming increasingly important. Nations, communities, and individual energy consumers need more locally available and accessible renewable energy sources to form part of diverse energy sources mix for a sustainable supply of their local energy demand. A country like South Africa, overwhelmed with demand against...
In order to continuously analyse the tile hadron calorimeter temperature data of the ATLAS off-line, the Tile-in-One (TiO) must be fully exploited. The Tile Calorimeter (TileCal) is a sampling hadronic calorimeter covering the central region of the ATLAS experiment, with steel as the absorber and plastic scintillators as the active medium. Wave Length Shifting fibres (WLS) gather light...
Waste to energy conversion is playing significant role in advancing economic development and health quality in the society. One of the technologies that exploits waste to energy conversion is biomass technology. The study focused on the development of a response surface model to predict the biogas production with input parameters being pH of slurry, slurry temperature and product of ambient...
Magnetic nano ferrites with superparamagnetic behaviour have attracted great interest in biomedicine. When these nano ferrites are coated, surface oxidation and aggregation can be reduced, enhancing their stability. In this work, CaFe2O4 nanoparticles (NPs) were synthesized through a glycol-thermal reaction method and coated with polymers viz: chitosan (CH) and polyvinyl alcohol (PVA) to yield...
Hidden sectors or dark sectors are hypothetical components appearing in various extensions to the Standard Model (SM), introduced to address phenomena not addressed by the SM (e.g the existence of dark matter or positron excess in the cosmic microwave background radiation flux). To incorporate the hidden sector, the introduction of an additional $U(1)_d$ dark gauge symmetry is necessary. This...
The $^{148}$Sm nucleus has Z=60 protons and N=86 neutrons. The neutron number represents only 4 neutrons above the N=82 shell gap. In the N=86 isotones, the competition between collective and single-particle modes of excitation results in a formation of different kinds of excited level structures.
The observed structures are interpreted as due to octupole vibrational states coupling with...
The importance of energy generation and storage cannot be overstated, given rising energy demands and the depletion of fossil fuels. Because of their low cost, abundance of elements, strong reversibility, and moderate energy density, sodium-ion batteries have piqued interest as a possible alternative for large-scale electrochemical energy storage. To provide critical fundamental insights into...
The Standard Model is widely accepted as one of the most successful predictive theories of Physics, providing insight into the fundamental building blocks of the universe. Over the last few decades this model has shown signs of incompleteness, most of which are attributed to Neutrinos. Within the confines of the standard model a discrepancy exists related to vanishing Neutrino masses, which...
Abstract
An innovative way of performing gamma column scanning was implemented in which the results are presented as a 2 dimensional density plot. Computed laminography is used for image reconstruction using experimentally obtained data to produce a 2D image from 1D projection of the column’s interior. Snark14 software, which is used for 2D image reconstruction from 1D projections was used...
Advanced sensing technology is required for the detection of gases and volatile organic compounds (VOCs) for application in environmental monitoring, disease diagnosis, and smart agriculture. Among the many materials used as sensing layers, nanostructured semiconductor metal oxide-based sensing materials have recently gained preference owing to their outstanding sensitivity and high surface...
The main aim of this project will be to perform GEANT4 simulation as part of the medical imaging project which will be done using the Modern African Detector Laboratory (MANDELA) at University of Zululand. The university of Zululand Physics department is collaborating with the university of York Physics department and the university of the Western Cape in this research. Through this research...
Graphic carbon nitride (GCN) was synthesized through a direct pyrolysis of urea at different calcination temperatures (450,500, 550, and 600 ℃). The effect of the pyrolysis temperatures on the structural, compositional, morphological, and surface area properties were studied. The GCN powders were characterized through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR),...
The Monte Carlo simulation Code, Stopping Power, and Range of Ions in Matter (SRIM) has been effective among other binary collision approximation codes for estimating the level of damage produced due to ion irradiation in materials. This study estimated the level of damage by heavy and light-ion irradiation to Lutetium-Aluminium (Lu-Al) and gold materials with Au and proton ion implantation...
Following the anomaly observed in multi-lepton final states through the decays of heavy scalar resonance in 𝑍𝛾 data at the Large Hadron Collider via proton-proton collisions, we develop a Kernel density estimation-based machine learning model to generate synthetic dataset. The dataset comprises SM Higgs-like signals such as ggF, VBF, WH and ZH. Further we use weak supervised machine learning...
Ghost imaging is the process of reconstructing an image of an object using entangled photons. One of the entangled photons interacts with the object and is detected without spatial resolution while the other photon from the pair is detected with spatial resolution. When the two photons are detected in coincidence, an image of the object can be obtained with the help of projective masks. An...
General systems to monitor the atmospheric condition, such as humidity, temperature, and pollution are extensively used in research and also even for public health purposes. In terms of pollution, the atmospheric analysis can be performed by LIDAR, a local measuring station, or a ballon-based sensor.
The atmospheric sensor proposed aims to be a payload for a balloon or drone. As with other...
Prompt gamma rays (PGs) produced by nuclear collisions during proton therapy (PT) can be used for in vivo proton beam range verification through a technique known as prompt gamma imaging (PGI). During PT, the production of PGs within the tissue provides a reliable location map for the proton dose deposition. The detection of these PGs using a Compton Camera (CC) can be used to construct a...
We computationally investigated the adsorption behaviour of lithium oxides (LixOx) and magnesium oxides (MgxOx) onto pristine graphene during oxygen reduction reaction (ORR) for lithium air batteries operation using density functional theory (DFT). We proposed various pathways and studied different adsorption configurations in each system, comprising the O2, Li, and Mg as ORR reactants and the...
In Low Earth Orbit (LEO), some dangers spacecraft electronics are subjected to are high energy protons [1]. Their energies range from a few MeV to GeV [2]. The current shielding employed by spacecraft (consisting mainly of satellites) is insufficient in protecting internal electronics [3]. In the past, and still, an extensively researched avenue is to employ polymers and composites as a...
We demonstrate a simple method to fabricate all-solid-state thermally reduced Graphene Oxide (trGO) microsupercapacitors (µ-SCs) prepared using the atmospheric pressure chemical vapour deposition (AP-CVD) and a mask-free axidraw sketching apparatus. This is a quick, easily operational, cheap, safe, photoresist free, readily scalable method and requires no hazards reducing chemical. The XRD,...
A magnetohydrodynamic (MHD) pump is a device that can move/pump a metallic fluid by utilizing an electric current together with a magnetic field. The operation of the pump is based on the principles of an electrically conductive fluid that is exposed to electromagnetic forces. When a metallic fluid passes through the device, the current and magnetic field combine to produce the Lorentz force....
Despite several techniques of optimization of the yield of a solar cell, we remark that the use of a non-uniform doping distribution has not yet been explored. This work studies the effect of a non-uniform doping profile, on the output electrical power of a silicon solar cell. The uniform doping profile commonly used in conventional solar cells is replaced by a Gaussian doping distribution....
This work derives from the problematic low performance of organic solar cells (OSCs) and attempts to make a contribution to its improvement through an empirical exploration of the potential of graphene derivatives, graphene oxide (GO) and reduced graphene oxide (rGO), for incorporation in OSCs. Along this, GO and rGO were synthesized from the primary feedstock, synthetic graphite (SG). GO was...
Most areas in South Africa receive an average more than 2 500 hours of sunshine per year, and average solar-radiation levels range between 4.5 and 6.5kWh/m2 in one day. This has necessitated the use of solar energy in South Africa, solar energy lends itself to several potential uses and the country's solar-equipment industry is developing. Residential homes have since started installing solar...
The Tile Calorimeter of the ATLAS experiment at the Large Hadron Collider is a hadronic calorimeter that is designed to provide important information for the reconstruction of physics objects like hadrons, jets, tau-particles and missing transverse energy. The calorimeter also plays a role in the identification of muons. It is a hadronic sampling calorimeter that uses scintillating tiles that...
South Africa is faced with an energy crisis as it relies more on energy from fossil fuels. The use of Renewable energy technologies can be a solution to current energy crisis in South Africa leading to continuous load shedding. Waste-to-energy conversion is playing a significant role in advancing economic development and health quality in society. One of the technologies that exploit...
Deformable mirrors have predominantly been used in a wide range of fields such as adaptive optics due to the robustness they possess in terms of aberration correction. In this work we utilise the combination of interferometry and digital Stokes polarimetry to characterize the wavefront emerging from a deformable mirror. We achieve this by interfering two fields of orthogonal polarisation...
Proton therapy offers an advantage over traditional radiotherapy by depositing a therapeutic dose within a small volume. By exploring the secondary radiation from proton-nuclei interactions in the target, the energy deposition can be monitored to make up for the lack of {\it in vivo} dose measurements. One such method is Positron Emission Particle Tracking (PEPT) using PolarisJ Cadmium Zinc...
Axion-like particles (ALPs) are well motivated new particles that serve as candidates of beyond the Standard Model studies (BSM). In this work, we propose to probe the ALPs through p p → a j j at the Large Hadron Collider at energy 14 TeV. The considered ALP production is both t-channel and s-channels. We demonstrate that we could provide constrains the effective coupling strength between ALPs...
Whether considering our everyday perception of the surrounding environment or a sophisticated experimental setup, a characterization of a physical system is given in terms of measurement results of its observable properties. Thus, given that this characterization is not unique, it is necessary to consider which features are being observed as well as how they are being observed. In this...
Electronic devices that are made primarily of organic materials are significant for reducing electronic waste. The resistive switching properties of a chitosan/polyvinylpyrrolidone (PVP) polymer blend dispersed with CdTe/CdSe core-shell quantum dots are investigated. Both chitosan and polyvinylpyrrolidone (PVP) are non-hazardous to the environment. This composite was employed in the active...
Scientists are intrigued by the phenomenon of resistive switching in organic materials because of its potential for designing devices with reduced electronic waste footprint. We improved the resistive switching property of organic cow milk films in this study by introducing selenium (Se) particles. We built and tested four devices, each with a different mass per volume % of Se in milk:...
In the study of three-body weakly-bound systems, a three-body interaction is always introduced to take care of the dynamics that cannot be accounted for by two-body interactions. In order to get some insight into these dynamics, in this presentation, we study the relevance of the three-body interaction as the number of neutrons in the three-body system increases, considering helium-6. It is...
This analysis presents the search for the Standard Model Higgs that decays to a pair of dark Higgs to an eight-lepton final state via four dark vector bosons.
In this scenario, the SM Z boson can kinetically mix with the $U(1)_D$ gauge boson $Z_D$ while the dark Higgs S and the SM Higgs can exhibit mass mixing. Either of the Higgses can can be formed from gluon-gluon fusion and decay to the...
A hadronic calorimeter called Tile Calorimeter (TileCal) can be discovered in the center of the ATLAS detector. A sample calorimeter called TileCal employs steel plates as the absorber and plastic scintillating tiles as the active medium. Because about 30% of the total energy jets produced in a proton-proton collision are deposited in TileCal, it is crucial in the accurate reconstruction of...
A study of a single event to investigate signatures of possible trinnis event during quiet geomagnetic conditions. One of the signatures of trinni event is the high-speed flows, which were interpreted to be associated with the release of energy from a rapid reconfiguration of tail magnetic field lines due to magnetic reconnection. This type of event is known to be “trinni” event, using the...
The iThemba LABS segmented clover detector (TIGRESS type) comprises four HPGe crystals, each one segmented eight-fold. Such new generation Ge detectors are able to perform γ-ray tracking but are more complex to work with. In order to properly maximise the use of this detector a method to locate gamma-ray interaction points within the detector was developed. The gamma ray interaction points...
The sinc function is defined by
$$ sinc(x) =\frac{sin πx}{nx}. $$ with $$ sinc(0) = 1 $$ and $$ sinc(i) = 0 $$ for $$ i \neq 0. $$ Defining $$ s_{i}^{(h)} sinc \frac {(x-i)}{h} $$ gives a set of interpolating functions with nodes $ih$. However in some instances it is more desirable to have such a set of sinc related...
Multiferroic rare-earth composite oxides with a perovskite-like structure such as terbium manganites hold a wide range of correlated properties for next-generational devices characterized by high efficiency, low energy dissipation, and high storage density among other high-end capabilities. Some of the envisaged applications include solid-state refrigeration, 4-state memory storage,...
Solar energy is our most abundant source of renewable energy especially the use of photovoltaic material. Dye-Sensitized cells (DSSCs); a suitable photovoltaic material that has been under extensive research due to its low cost, simple preparation, low toxicity and ease of production. Hence, this research investigated the performance of two natural pigments extracted from two locally available...
Sifunda 1,2, O. Nubi 2, B. W. Mwakikunga 3, A. A. Akande 4*,
1.CSIR Nextgen Enterprises and Institutions, P O Box 395, Pretoria 0001, South Africa
2.University of Limpopo, Department of Physics, P/Bag X1106, Sovenga 0727, South Africa
3.School of Interdisciplinary and Graduate Studies, University of South Africa, UNISA 0003, Pretoria, South Africa
4.University of Sydney, School of...
During the United Nations General Assembly in September 2015, the 17 Sustainable Development Goals (SDGs) were approved, and to achieve these goals, we must work as a team. All of these SDGs require a basic knowledge of the sciences in order to be achieved. In order to ensure a world that is balanced, sustainable, and inclusive, the International Year of Basic Sciences for Sustainable...
In 1970, a Coulomb excitation experiment was done in order to determine Spectroscopic Quadrupole moment of Argon-36 (36Ar) in its first excited state which has the total angular momentum of 2 and a positive parity. The 36Ar ion beam was bombarded towards a stationary Lead-206 (206Pb) target The Spectroscopic quadrupole moment was determined to be 0.11 ±0.06 e.b. At the time of the experiment,...
ABSTRACT
Titanium (Ti) and its alloys have been widely used as implant materials due to their outstanding mechanical characteristics and biocompatibility. Some of the applications includes orthopedic, and endoderm surgeries etc. However, there is a great concern regarding the difference in the implant material’s Young’s modulus and that of natural bone. With prolonged use, Ti alloys releases...
Abstract:
Titanium alloys have been used in the bio-medical industry since the 1800s.They are incredibly important among bio-medical implants because of their high strength and resistance to fatigue deterioration. Recently, the development of non-toxic, more biocompatible and allergy-free components has been of outmost importance. The purpose of this study was to use first principle approach...
Abstract. The Tile Calorimeter (TileCal) is a hadronic sampling calorimeter which forms a part of the ATLAS detector, one of the major experiments at the Large Hadron Collider (LHC). As part of the scheduled Phase-II upgrade of the LHC, and subsequently TileCal, the backend electronics are undergoing an upgrade to their Low Voltage Power Supply (LVPS) systems; electronics have a high...
This paper demonstrates how using deep neural networks can improve quality control of Low Voltage Power Supply (LVPS) Boards. Deep Neural Networks (DNNs) as a machine learning algorithm is used to analyze complex data from the LVPS Boards. The first initial testing done on the boards determines their reliability and performance. A total of eleven tests with a binary metric of PASS/FAIL make up...
In high-energy physics, the study of the Theory and Phenomenology of Relativistic Heavy-Ion Collisions examines how atomic nuclei behave when they collide at exceedingly fast speeds, nearly at the speed of light. These collisions produce rich observable signatures that can provide insight into the properties of quark-gluon plasmas (QGPs), a state of matter believed to exist at high...
South African physics dates back to 1751 when Nicholas Louis de Lacaille made significant astronomical observations of the southern sky at the Cape of Good Hope. Also, at Cape Town's Royal Observatory, John Herschel began investigating double stars, clusters, and nebulae between 1834 and 1838. In the second half of the 19th century, geomagnetic and surveying work was introduced, and several...
Using NLP to predict Alert Signals from the ATLAS TileCal
Detector Control System at CERN
Nicholas Perikli on behalf of Tile Calorimeter Systems Team.
School of Physics and Institute for Collider Particle Physics, University of the Witwatersrand, Johannesburg, South Africa
Particle physics data consists of patterns in measurements that can be separated into hot topics and more...
