https://vital.seals.ac.za/vital/access/manager/Index en-us 5 Modeling and measurement of torqued procession in radio pulsars https://vital.seals.ac.za/vital/access/manager/Repository/vital:5475 Wed 27 Oct 2021 10:07:08 SAST ]]> Combined spectral and stimulated luminescence study of charge trapping and recombination processes in α-Al2O3:C https://vital.seals.ac.za/vital/access/manager/Repository/vital:28235 Wed 15 Sep 2021 14:30:53 SAST ]]> Classical and quantum picture of the interior of two-dimensional black holes https://vital.seals.ac.za/vital/access/manager/Repository/vital:20531 Wed 12 May 2021 23:48:00 SAST ]]> Some ionospheric effects observed at sunrise https://vital.seals.ac.za/vital/access/manager/Repository/vital:5513 Wed 12 May 2021 23:37:53 SAST ]]> The development and evaluation of a Nd:YAG laser incorporating an unstable resonator https://vital.seals.ac.za/vital/access/manager/Repository/vital:5512 Wed 12 May 2021 23:35:05 SAST ]]> Finite precision arithmetic in Polyphase Filterbank implementations https://vital.seals.ac.za/vital/access/manager/Repository/vital:38503 Wed 12 May 2021 23:20:29 SAST ]]> Oblique incidence investigations of the ionosphere over the Southern Ocean https://vital.seals.ac.za/vital/access/manager/Repository/vital:5438 Wed 12 May 2021 23:11:44 SAST ]]> Towards modelling the formation of ore bodies initial results dealing with the fluid mechanical aspects of magma chamber convection https://vital.seals.ac.za/vital/access/manager/Repository/vital:5492 Wed 12 May 2021 23:08:31 SAST ]]> An investigation into improved ionospheric F1 layer predictions over Grahamstown, South Africa https://vital.seals.ac.za/vital/access/manager/Repository/vital:5511 Wed 12 May 2021 22:45:13 SAST ]]> Thermoluminescence of secondary glow peaks in carbon-doped aluminium oxide https://vital.seals.ac.za/vital/access/manager/Repository/vital:5537 Wed 12 May 2021 22:37:25 SAST ]]> Comparison of A₄ neutrino mass models https://vital.seals.ac.za/vital/access/manager/Repository/vital:5554 Wed 12 May 2021 22:30:24 SAST ]]> Analysing emergent time within an isolated Universe through the application of interactions in the conditional probability approach https://vital.seals.ac.za/vital/access/manager/Repository/vital:38547 Wed 12 May 2021 20:57:26 SAST ]]> The 2326 MHZ radio continuum emission of the milky way https://vital.seals.ac.za/vital/access/manager/Repository/vital:5450 Wed 12 May 2021 20:17:57 SAST ]]> An analysis of ionospheric response to geomagnetic disturbances over South Africa and Antarctica https://vital.seals.ac.za/vital/access/manager/Repository/vital:5534 Wed 12 May 2021 20:15:43 SAST ]]> Nonlinear optical responses of phthalocyanines in the presence of nanomaterials or when embedded in polymeric materials https://vital.seals.ac.za/vital/access/manager/Repository/vital:25548 Wed 12 May 2021 20:07:23 SAST ]]> The photo-fluorescence properties of some organic materials https://vital.seals.ac.za/vital/access/manager/Repository/vital:5514 Wed 12 May 2021 20:04:33 SAST ]]> Observations of diffuse radio emission in the Perseus Galaxy Cluster https://vital.seals.ac.za/vital/access/manager/Repository/vital:38233 Wed 12 May 2021 19:59:26 SAST ]]> First H F Doppler soundings of the ionosphere at SANAE https://vital.seals.ac.za/vital/access/manager/Repository/vital:5500 Wed 12 May 2021 19:56:40 SAST ]]> Thermoluminescence of annealed synthetic quartz https://vital.seals.ac.za/vital/access/manager/Repository/vital:19957 Wed 12 May 2021 19:55:06 SAST ]]> Expanding the capabilities of the DPS lonosonde system https://vital.seals.ac.za/vital/access/manager/Repository/vital:5560 Wed 12 May 2021 19:50:08 SAST ]]> Assignment of spin and parity to states in the nucleus ¹⁹⁶T1 https://vital.seals.ac.za/vital/access/manager/Repository/vital:5558 Wed 12 May 2021 19:49:57 SAST ]]> Tomographic imaging of East African equatorial ionosphere and study of equatorial plasma bubbles https://vital.seals.ac.za/vital/access/manager/Repository/vital:28516 Wed 12 May 2021 19:46:51 SAST ]]> Computer control of a barry research chirpsounder https://vital.seals.ac.za/vital/access/manager/Repository/vital:5507 Wed 12 May 2021 19:36:46 SAST ]]> Some properties of magnetospheric electrons observed west of Sanae https://vital.seals.ac.za/vital/access/manager/Repository/vital:5523 Wed 12 May 2021 19:23:20 SAST ]]> Modelling storm-time TEC changes using linear and non-linear techniques https://vital.seals.ac.za/vital/access/manager/Repository/vital:30762 4. The performance evaluation of MIDAS compared with ANNs to reconstruct storm-time TEC over the African low- and mid-latitude regions showed that MIDAS and ANNs provide comparable results. Their respective mean absolute error (MAE) values were 4.81 and 4.18 TECU. The ANN model was, however, found to perform 24.37 % better than MIDAS at estimating storm-time TEC for low latitudes, while MIDAS is 13.44 % more accurate than ANN for the mid-latitudes. When their performances are compared with the IRI model, both MIDAS and ANN model were found to provide more accurate storm-time TEC reconstructions for the African low- and mid-latitude regions. A comparative study of the performances of EOF, NLRA, ANN, and IRI models to estimate TEC during geomagnetic storm conditions over various latitudes showed that the ANN model is about 10 %, 26 %, and 58 % more accurate than EOF, NLRA, and IRI models, respectively, while EOF was found to perform 15 %, and 44 % better than NLRA and IRI, respectively. It was further found that the NLRA model is 25 % more accurate than the IRI model. We have also investigated for the first time, the role of meridional neutral winds (from the Horizontal Wind Model) to storm-time TEC modelling in the low latitude, northern and southern hemisphere mid-latitude regions of the African sector, based on ANN models. Statistics have shown that the inclusion of the meridional wind velocity in TEC modelling during geomagnetic storms leads to percentage improvements of about 5 % for the low latitude, 10 % and 5 % for the northern and southern hemisphere mid-latitude regions, respectively. High-latitude storm-induced winds and the inter-hemispheric blows of the meridional winds from summer to winter hemisphere have been suggested to be associated with these improvements.]]> Wed 12 May 2021 19:12:42 SAST ]]> Developing an ionospheric map for South Africa https://vital.seals.ac.za/vital/access/manager/Repository/vital:5459 Wed 12 May 2021 19:06:06 SAST ]]> The selection and evaluation of grey-level thresholds applied to digital images https://vital.seals.ac.za/vital/access/manager/Repository/vital:5443 Wed 12 May 2021 18:55:44 SAST ]]> Thermoluminescence of synthetic quartz annealed beyond its second phase inversion temperature https://vital.seals.ac.za/vital/access/manager/Repository/vital:25577 Wed 12 May 2021 18:51:02 SAST ]]> A feasibility study into the possibility of ionospheric propagation of low VHF (30-35 MHZ) signals between South Africa and Central Africa https://vital.seals.ac.za/vital/access/manager/Repository/vital:5465 Wed 12 May 2021 18:48:02 SAST ]]> Observation and processing of 2.3 GHz radio astronomy survey data https://vital.seals.ac.za/vital/access/manager/Repository/vital:5505 Wed 12 May 2021 18:42:52 SAST ]]> A study of why some physic concepts in the South African Physical Science curriculum are poorly understood in order to develop a targeted action-research intervention for Newton’s second law https://vital.seals.ac.za/vital/access/manager/Repository/vital:38575 Wed 12 May 2021 18:39:05 SAST ]]> Challenges in topside ionospheric modelling over South Africa https://vital.seals.ac.za/vital/access/manager/Repository/vital:5453 Wed 12 May 2021 18:37:56 SAST ]]> Radio observation of the Gum Nebula Region https://vital.seals.ac.za/vital/access/manager/Repository/vital:5485 Wed 12 May 2021 18:37:47 SAST ]]> Data reduction techniques for Very Long Baseline Interferometric spectropolarimetry https://vital.seals.ac.za/vital/access/manager/Repository/vital:5457 Wed 12 May 2021 18:24:03 SAST ]]> Thermoluminescence characteristics of synthetic quartz https://vital.seals.ac.za/vital/access/manager/Repository/vital:5538 Wed 12 May 2021 18:18:39 SAST ]]> The effects of particle precipitation on the ionosphere in the South Atlantic Anomaly Region https://vital.seals.ac.za/vital/access/manager/Repository/vital:5463 Tue 31 Aug 2021 10:06:57 SAST ]]> Predictability of Geomagnetically Induced Currents using neural networks https://vital.seals.ac.za/vital/access/manager/Repository/vital:5483 Thu 26 Aug 2021 14:37:41 SAST ]]> The EPR paradox: back from the future https://vital.seals.ac.za/vital/access/manager/Repository/vital:20338 Thu 23 Jun 2022 11:24:04 SAST ]]> Dynamics of stimulated luminescence in natural quartz: Thermoluminescence and phototransferred thermoluminescence https://vital.seals.ac.za/vital/access/manager/Repository/vital:38509 Thu 13 May 2021 15:55:13 SAST ]]> CubiCal: a fast radio interferometric calibration suite exploiting complex optimisation https://vital.seals.ac.za/vital/access/manager/Repository/vital:30711 Thu 13 May 2021 15:04:39 SAST ]]> The implementation of a core architecture for geophysical data acquisition https://vital.seals.ac.za/vital/access/manager/Repository/vital:5471 Thu 13 May 2021 13:16:36 SAST ]]> Development of a neural network based model for predicting the occurrence of spread F within the Brazilian sector https://vital.seals.ac.za/vital/access/manager/Repository/vital:5460 Thu 13 May 2021 09:13:17 SAST ]]> Structure of the nucleus ¹¹⁴Sn using gamma-ray coincidence data https://vital.seals.ac.za/vital/access/manager/Repository/vital:5562 Thu 13 May 2021 08:52:22 SAST ]]> A VLBI polarisation study of 43 GHZ SiO masers towards VY CMA https://vital.seals.ac.za/vital/access/manager/Repository/vital:5498 Thu 13 May 2021 08:22:08 SAST ]]> Investigation into the extended capabilities of the new DPS-4D ionosonde https://vital.seals.ac.za/vital/access/manager/Repository/vital:5472 Thu 13 May 2021 08:08:05 SAST ]]> A new empirical model for the peak ionospheric electron density using neural networks https://vital.seals.ac.za/vital/access/manager/Repository/vital:5478 Thu 13 May 2021 07:39:27 SAST ]]> Measuring the RFI environment of the South African SKA site https://vital.seals.ac.za/vital/access/manager/Repository/vital:5474 Thu 13 May 2021 07:16:45 SAST ]]> Designing and implementing a new pulsar timer for the Hartebeesthoek Radio Astronomy Observatory https://vital.seals.ac.za/vital/access/manager/Repository/vital:5458 Thu 13 May 2021 07:10:11 SAST ]]> Long-term analysis of ionospheric response during geomagnetic storms in mid, low and equatorial latitudes https://vital.seals.ac.za/vital/access/manager/Repository/vital:28517 Thu 13 May 2021 07:06:25 SAST ]]> Calibration and interpretation of A 2.3 GHz continuum survey https://vital.seals.ac.za/vital/access/manager/Repository/vital:5502 L > -58° is studied. It is dominated by a plateau of emission for L < -26°. This is interpreted as a combination of thermal and nonthermal radiation emitted by a ring of gas symmetric about the galactic centre with a radius of 4 - 6 kpc.]]> Thu 13 May 2021 06:53:12 SAST ]]> The effect of different parameters on the rupture properties of leather in a tensile test https://vital.seals.ac.za/vital/access/manager/Repository/vital:5462 Thu 13 May 2021 06:48:58 SAST ]]> Aspects of the symplectic and metric geometry of classical and quantum physics https://vital.seals.ac.za/vital/access/manager/Repository/vital:5452 Thu 13 May 2021 06:28:45 SAST ]]> Studies in ionospheric ray tracing https://vital.seals.ac.za/vital/access/manager/Repository/vital:5501 Thu 13 May 2021 06:28:30 SAST ]]> A VLBI study of OH masers in a proto-planetary nebula OH 0.9+1.3 https://vital.seals.ac.za/vital/access/manager/Repository/vital:5499 Thu 13 May 2021 06:26:01 SAST ]]> Multi-instrument observations of ionospheric irregularities over South Africa https://vital.seals.ac.za/vital/access/manager/Repository/vital:5476 Thu 13 May 2021 06:18:50 SAST ]]> Observations of glitches in PSR 0833-45 and 1641-45 https://vital.seals.ac.za/vital/access/manager/Repository/vital:5480 Thu 13 May 2021 06:12:50 SAST ]]> Real-time audio spectrum analyser research, design, development and implementation using the 32 bit ARMR Cortex-M4 microcontroller https://vital.seals.ac.za/vital/access/manager/Repository/vital:25997 Thu 13 May 2021 06:12:17 SAST ]]> TiRiFiG, a graphical 3D kinematic modelling tool https://vital.seals.ac.za/vital/access/manager/Repository/vital:30558 Thu 13 May 2021 06:10:31 SAST ]]> Link between ghost artefacts, source suppression and incomplete calibration sky models https://vital.seals.ac.za/vital/access/manager/Repository/vital:5556 Thu 13 May 2021 06:07:57 SAST ]]> A Bayesian approach to tilted-ring modelling of galaxies https://vital.seals.ac.za/vital/access/manager/Repository/vital:38466 Thu 13 May 2021 05:58:42 SAST ]]> Solar cycle effects on GNSS-derived ionospheric total electron content observed over Southern Africa https://vital.seals.ac.za/vital/access/manager/Repository/vital:5489 Thu 13 May 2021 05:54:01 SAST ]]> Progress towards the development and implementation of an unambiguous copper wire fingerprinting system https://vital.seals.ac.za/vital/access/manager/Repository/vital:5484 Thu 13 May 2021 05:52:34 SAST ]]> Observing cosmic reionization with PAPER: polarized foreground simulations and all sky images https://vital.seals.ac.za/vital/access/manager/Repository/vital:29218 0.3 h Mpc -¹ We also analyzed data from the last observing season of PAPER via all-sky imaging with a view to characterize the foregrounds. We generated an all-sky catalogue of 88 sources down to a flux density of 5 Jy. Moreover, we measured both polarized point source and the Galactic diffuse emission, and used these measurements to constrain our model of polarization leakage. We find the leakage due to a population of point sources to be 12% lower than the prediction from our polarized model.]]> Thu 13 May 2021 05:43:39 SAST ]]> Observations of diffuse radio emission in the Abell 773 galaxy cluster https://vital.seals.ac.za/vital/access/manager/Repository/vital:38394 Thu 13 May 2021 05:41:52 SAST ]]> MEQSILHOUETTE: a mm-VLBI observation and signal corruption simulator https://vital.seals.ac.za/vital/access/manager/Repository/vital:25019 Thu 13 May 2021 05:32:08 SAST ]]> Modelling and investigating primary beam effects of reflector antenna arrays https://vital.seals.ac.za/vital/access/manager/Repository/vital:38635 Thu 13 May 2021 05:23:36 SAST ]]> Thermoluminescence of natural quartz https://vital.seals.ac.za/vital/access/manager/Repository/vital:5543 Thu 13 May 2021 05:21:09 SAST ]]> The SKA's the limit : on the nature of faint radio sources https://vital.seals.ac.za/vital/access/manager/Repository/vital:5504 Thu 13 May 2021 05:20:46 SAST ]]> A neural network based ionospheric model for the bottomside electron density profile over Grahamstown, South Africa https://vital.seals.ac.za/vital/access/manager/Repository/vital:5477 Thu 13 May 2021 05:19:34 SAST ]]> Optimizing MIDAS III over South Africa https://vital.seals.ac.za/vital/access/manager/Repository/vital:5517 Thu 13 May 2021 05:10:35 SAST ]]> The observation of extended sources with the Hartebeesthoek radio telescope https://vital.seals.ac.za/vital/access/manager/Repository/vital:5479 Thu 13 May 2021 05:09:50 SAST ]]> A pilot wide-field VLBI survey of the GOODS-North field https://vital.seals.ac.za/vital/access/manager/Repository/vital:30027 5x105 K and >6x1021 W Hz-1 respectively. This work demonstrates that automated post-processing pipelines for wide-field, uniform sensitivity VLBI surveys are feasible and indeed made more efficient with new software, wide-field imaging algorithms and more purpose-built source- finders. This broadens the discovery space for future wide-field surveys with upcoming arrays such as the African VLBI Network (AVN), MeerKAT and the Square Kilometre Array (SKA).]]> Thu 13 May 2021 05:08:27 SAST ]]> Empirical modelling of the solar wind influence on Pc3 pulsation activity https://vital.seals.ac.za/vital/access/manager/Repository/vital:5464 Thu 13 May 2021 05:04:36 SAST ]]> Properties of traveling ionospheric disturbances (TIDs) over the Western Cape, South Africa https://vital.seals.ac.za/vital/access/manager/Repository/vital:5557 Thu 13 May 2021 04:57:39 SAST ]]> Machine learning methods for calibrating radio interferometric data https://vital.seals.ac.za/vital/access/manager/Repository/vital:31398 Thu 13 May 2021 04:55:12 SAST ]]> The establishment of a Lidar facility at Rhodes University https://vital.seals.ac.za/vital/access/manager/Repository/vital:5445 Thu 13 May 2021 04:52:35 SAST ]]> Calibration and imaging with variable radio sources https://vital.seals.ac.za/vital/access/manager/Repository/vital:24721 Thu 13 May 2021 04:51:42 SAST ]]> The search for an ionospheric model suitable for real-time applications in HF radio communications https://vital.seals.ac.za/vital/access/manager/Repository/vital:5488 Thu 13 May 2021 04:41:21 SAST ]]> A 150 MHz all sky survey with the Precision Array to Probe the Epoch of Reionization https://vital.seals.ac.za/vital/access/manager/Repository/vital:34556 Thu 13 May 2021 04:40:36 SAST ]]> Physics and applications of scintillation detectors https://vital.seals.ac.za/vital/access/manager/Repository/vital:5482 Thu 13 May 2021 04:31:15 SAST ]]> Finite element modelling of magma convection and attendant groundwater flow https://vital.seals.ac.za/vital/access/manager/Repository/vital:5467 Thu 13 May 2021 04:24:15 SAST ]]> The development of an improved coded-pulse, vertical-incidence ionosonde https://vital.seals.ac.za/vital/access/manager/Repository/vital:5436 Thu 13 May 2021 03:43:09 SAST ]]> Distributed control applications using local area networks: a LAN based power control system at Rhodes University https://vital.seals.ac.za/vital/access/manager/Repository/vital:5461 Thu 13 May 2021 03:37:19 SAST ]]> Advanced ionospheric chirpsounding https://vital.seals.ac.za/vital/access/manager/Repository/vital:5446 Thu 13 May 2021 03:33:12 SAST ]]> Thermoluminescence and phototransferred phermoluminescence of synthetic quartz https://vital.seals.ac.za/vital/access/manager/Repository/vital:38472 Thu 13 May 2021 03:05:20 SAST ]]> Modelling Ionospheric vertical drifts over the African low latitude region https://vital.seals.ac.za/vital/access/manager/Repository/vital:28396 Thu 13 May 2021 02:06:20 SAST ]]> Foreground simulations for observations of the global 21-cm signal https://vital.seals.ac.za/vital/access/manager/Repository/vital:30557 Thu 13 May 2021 01:46:55 SAST ]]> Beta decay of 100/400 Zr produced in neutron-induced fission of natural uranium https://vital.seals.ac.za/vital/access/manager/Repository/vital:20353 Thu 13 May 2021 01:43:27 SAST ]]> A light-emitting-diode pulsing system for measurement of time-resolved luminescence https://vital.seals.ac.za/vital/access/manager/Repository/vital:20976 Thu 13 May 2021 01:37:18 SAST ]]> Geomagnetically induced current characteristics in southern Africa https://vital.seals.ac.za/vital/access/manager/Repository/vital:5469 Thu 13 May 2021 01:31:54 SAST ]]> Advanced radio interferometric simulation and data reduction techniques https://vital.seals.ac.za/vital/access/manager/Repository/vital:26875 Thu 13 May 2021 01:03:59 SAST ]]> A global ionospheric F2 region peak electron density model using neural networks and extended geophysically relevant inputs https://vital.seals.ac.za/vital/access/manager/Repository/vital:5470 Thu 13 May 2021 00:53:58 SAST ]]> Computer control of an HF chirp radar https://vital.seals.ac.za/vital/access/manager/Repository/vital:5455 Thu 13 May 2021 00:45:07 SAST ]]> A contribution to TEC modelling over Southern Africa using GPS data https://vital.seals.ac.za/vital/access/manager/Repository/vital:5456 Thu 13 May 2021 00:26:54 SAST ]]> Forecasting solar cycle 24 using neural networks https://vital.seals.ac.za/vital/access/manager/Repository/vital:5468 Thu 13 May 2021 00:24:49 SAST ]]> Variability analysis of a sample of potential southern calibration sources https://vital.seals.ac.za/vital/access/manager/Repository/vital:5495 Thu 13 May 2021 00:13:28 SAST ]]> Single station TEC modelling during storm conditions https://vital.seals.ac.za/vital/access/manager/Repository/vital:20545 Thu 13 May 2021 00:00:25 SAST ]]> Accelerated implementations of the RIME for DDE calibration and source modelling https://vital.seals.ac.za/vital/access/manager/Repository/vital:42199 Thu 13 Jul 2023 12:40:08 SAST ]]> Behaviour of quiet time ionospheric disturbances at African equatorial and midlatitude regions https://vital.seals.ac.za/vital/access/manager/Repository/vital:28228 Fri 17 Sep 2021 14:51:46 SAST ]]> Data compression, field of interest shaping and fast algorithms for direction-dependent deconvolution in radio interferometry https://vital.seals.ac.za/vital/access/manager/Repository/vital:21089 Fri 07 Jul 2023 06:30:13 SAST ]]>