University of South Africa

About: University of South Africa is a education organization based out in Pretoria, South Africa. It is known for research contribution in the topics: Context (language use) & Population. The organization has 8478 authors who have published 19960 publications receiving 237688 citations. The organization is also known as: Unisa.

Complexity Theories, Social Theory, and the Question of Social Complexity

Abstract: In this article, the author argues that complexity theories have limited use in the study of society, and that social processes are too complex and particular to be rigorously modeled in complexity terms. Theories of social complexity are shown to be inadequately developed, and typical weaknesses in the literature on social complexity are discussed. Two stronger analyses, of Luhmann and of Harvey and Reed, are also critically considered. New considerations regarding social complexity are advanced, on the lines that simplicity, complexity that can be modeled, and incondensible complexity permeate society simultaneously. The difficulty of establishing complexity models for processes involving ongoing interpretation is discussed. It is argued that the notions of system and environment need recasting in social studies. Existing social studies and literature, it is argued, reflect a polymorphous, contextual, contingent, labyrinthine, dramatic and political face to social complexity. Students of social complexi...

Synthesis, characterization and gas-sensing properties of SILAR deposited ZnO-CdO nano-composite thin film

Abstract: The deposition of ZnO-CdO thin films are carried out using successive ionic layer adsorption and reaction (SILAR) method at room temperature. The deposited ZnO-CdO thin films have been characterized using FT-Raman spectroscopy, scanning electron microscopy, UV-vis spectrophotometer, two point probe resistivity method, and contact angle mode. Raman spectroscopy show various peaks from the as deposited films which disappeared after annealing. The SEM reveals the morphology of the films nanosized smooth interlocked sheets all over the surface. The bandgap value of 3.8 eV is observed for as deposited but decreased to 2.9 eV after annealing. Activation energies of 0.43 and 0.11 eV are estimated for the as deposited film and annealed film, respectively. The Gas response of the ZnO-CdO composite film shows maximum (about 50%) at 623 K upon exposure to 780 ppm of LPG.

ZnO doped single wall carbon nanotube as an active medium for gas sensor and solar absorber

Abstract: In this paper, we reported the synthesis of high-quality ZnO-doped SWCNT (ZnO:SWCNT) nanostructures by perfume spray pyrolysis on copper substrate. The synthesized ZnO:SWCNT nanoparticle explored for the optoelectronic properties and its potential application in photonic devices. In this investigation, the ZnO:SWCNT was blended with the solar absorber of thin film organic solar cells which is found to be a successful mechanism in enhancing the photo-generated current in the devices. The best device performance was found at 6% concentration of ZnO:SWCNT by weight in the solution phase of the solar absorber. Furthermore, the pure ZnO:SWCNT as a gas sensor shows good sensitivity to ethanol at different gas loading in ppm. We observed for the first time a high gas sensing activity of ZnO:SWCNT powder which is related to surface state, oxygen adsorption, grain size and lattice defects. The article discusses about the techniques employed during gas sensing measurements using various functionalization strategies.

A comparative study on the morphological features of highly ordered MgO:AgO nanocube arrays prepared via a hydrothermal method

Abstract: II–VI semiconductor nanotubes are a recently developed class of nanomaterials whose unique photophysical properties are helping to create a new generation of nanomaterials in the field of photonics and microelectronics. In this report, we examine the progress in adapting these nanomaterials for several optoelectronics applications followed by characterization studies. Magnesium oxide and silver oxide (MgO:AgO) nanoparticles were synthesized using a hydrothermal method by taking magnesium nitrate, silver oxide and glycine. X-ray diffraction (XRD) results showed that the peaks are consistent with a pure phase cubic structure of MgO. The XRD pattern also confirmed the crystallinity and phase purity of the sample. Nanocrystal sizes were found to be up to 25 nm as revealed by XRD and HRTEM. Photoluminescence measurement (PL) reveals the systematic shift of the emission band towards lower wavelength thereby ascertaining the quantum confinement effect.

Handling cultural diversity in education in South Africa

Abstract: For more than a decade South African education has been characterised by desegregation in an effort to accommodate the diverse nature of society. This article discusses the issues and problems related to the handling of diversity in education. Many variables have influenced the response of schools to learner diversity. These responses played out in several approaches and models. It is also argued that the decentralisation of education provided racially defined communities the legal means to preserve their privileges, that schools have been much more successful at meeting the demand for racial desegregation than achieving the ideal of social integration and that messages forthcoming from “race” affect black learners more negatively than other learners in South Africa. Because handling diversity in education is so complex, it is proposed that educators need to recognise the validity of differences. It requires firstly a reappraisal of educators’ own personal and of institutional ideologies and perceptions, and secondly a frank conviction and dedication to facilitate and manage learner diversity.