Monitoring African buffalo (Syncerus caffer) and cattle (Bos taurus) movement across a damaged veterinary control fence at a Southern African wildlife/livestock interface

We test the extent to which fence damage or fence permeability (resulting from human and elephant damage) influences patterns of cattle and buffalo movement at the periphery of Gonarezhou National Park, Zimbabwe. We used spoor data to detect and compare the frequency of cattle and buffalo movement across the fence boundary. Results show that spoor proportions for cattle were significantly higher on fence partially damaged by humans than buffalo spoor. Conversely, buffalo spoor proportions were significantly higher on sections with totally removed fence as a result of elephant damage. Results suggest that cattle and buffalo use different sections of the damaged fence. (Résumé d'auteur

Spatial overlap between sympatric wild and domestic herbivores links to resource gradients

In this study, we investigated the relationship between resource gradients and overlap between wild and domestic herbivores in a southern African ecosystem. We used an Enhanced Vegetation Index (EVI) to identify and test the presence of resource gradients i.e. vegetation greenness between agricultural areas and conservation areas in Southeastern Zimbabwe, part of the Great Limpopo Transfrontier Conservation Area. We then tested whether these resource gradients coincide with GPS collared cattle (Bos taurus) movements into wildlife areas, as well as drive spatial overlaps between cattle and the GPS collared African buffalo (Syncerus caffer). Results showed that resource gradients although variable, exist between the conservation area and surrounding agricultural area. Cattle used the conservation area less than expected during the dry season when vegetation greenness in the communal land was relatively lower than in the conservation area. Significant spatial segregation between cattle and buffalo occurred during the wet season and late dry season, while spatial aggregation occurred during the early dry season. Intensity of habitat overlap between cattle and buffalo during the early dry season was relatively high in habitats preferred by both species. Our results suggest that cattle movement into conservation areas is linked to resource gradients. (Résumé d'auteur

Early Adolescents’ Self-esteem and Achievement

A ZJER article on adolescents' self- esteem.This study examined the relationship between self esteem and academic achievement in early adolescents in randomly selected primary school classes. Self-esteem was measured by a self report questionnaire while school achievement was measured by scores from mid-year examinations designed by teachers. The results of a t-test showed significant differences in self-esteem between boys and girls, with girls reporting lower levels of self-esteem. While the study found no significant gender differences in achievement, there were however significant correlations between self-esteem, age, and school achievement

Information and Communication Technology (ICT) Skills for Bachelor of Education Degree Students at the University of Zimbabwe: Implications for University Policy on a Computer Course for Undergraduate Student Teachers

A ZJER article on ICT training for first year undergraduate student teachers at the University of Zimbabwe.The development of appropriate computer literacy skills within all school teachers for non-computing subjects has recently become a strong international challenge. This is in view of the increasing use of computers in enhancing learning in all educational institutions, including colleges and universities. Employing a survey methodology, this study sought to provide answers to questions that included: what computer skills do undergraduate student teachers bring with them to the University of Zimbabwe; v*hat computer equipment was available at the teachers ’ schools and homes; and what factors influenced the teachers ’ computer skills development? The findings indicated that the students teachers were generally from rural areas and had no, or very little, experience with computers, with most of them using a computer for the first time. The study recommends strengthening the course through strategies such as increasing the computer equipment available for trainning and offering a separate certificate for the course as an incentive

An Analysis of Technical and Vocational Education Policy Growth and Development in the United States of America, the United Kingdom and Africa

A ZJER article on technical education policy in Africa, USA and the UK.Socio-economic development is negatively affected if Technical and Vocational Education (TVE) policy growth and development is not purposefully aligned injandem with the national economic thrust. This paper starts by defining the concept of TVE before analysing this process in American, British and African systems. The analysis suggests that Africa has important lessons to learn from the two developed countries, especially on ensuring that TVE systems produce graduates that stay within the country and contribute towards national socio-economic development. African TVE policies have to address the skills, knowledge and attitude needs of local communities, including rural areas, the informal sector, the unemployed and women. The paper suggests that TVE systems should aim at producing indigenous African researchers and designers who will utilise local resources to come up with internationally competitive appropriate technologies and products. This should bring socio-economic development to the continent, thereby reducing TVE system graduate unemployment and emigration

The Adoption of E-learning by Students in Zimbabwean Universities in the Wake of COVID-19

COVID-19 effects have been felt in the education sector worldwide where schools, colleges, and universities were closed as a way to reduce the spread of the deadly pandemic and loss of lives. The Ministry of Higher and Tertiary Education. advocate that no child should be left behind during the COVID-19 era, therefore gave a directive for universities to use other alternative means of teaching and learning to continuously provide teaching and learning to students during the series of lockdown. An efficient eLearning system in universities is very important as an alternative to faceto-face teaching and learning in this COVID-19 era to have continuity in teaching and learning during the induced lockdowns. Success in online learning can be achieved by understanding the level of readiness of online learning environments. The main objective of the study was to evaluate the adoption of online learning by students in Zimbabwean universities. A descriptive online survey employing questionnaires to collect data on the adoption of eLearning by Zimbabwean universities students was used. Results indicated various eLearning platforms have been introduced in Zimbabwean universities though there is a need for eLearning infrastructure to be availed, students to be trained or students to effectively adopt the eLearning

An investigation into the effects of mould temperature on injection moulded HDPE gear performance

Polymers and polymer composite materials are emerging as viable front runner alternatives to metallic gears as they offer distinct advantages, such as good weight to strength ratios, the ability to run without external lubrication, less noise when running, and a lower coefficient of friction. Polymer gears undergo complex microstructural changes such as hysteresis, viscous flow, and elastic deformation which affect their performance capabilities to a greater extent compared to those of metallic gears. These differences mean that the failure of these gears differ to those made from metals. The wear behaviour and performance of polymetric gears has generated much interest from researchers over the past few decades, but to date there has been little focus on understanding the link between the input parameters used during the manufacturing process, and their corresponding physical and performance characteristics. This approach seems peculiar to polymer gears, as metal gears tend to be tested and graded not only by their material type, but also according to their mode of manufacture. Of particular importance during the manufacturing process for both metallic and polymetric gears, is the mould temperature (cooling temperature) of the molten material. Techniques such as quenching, annealing, or tempering, are used in metallic gear production to alter the cooling rate, which in turn alters the internal microstructure of the gear. The main objective in altering the cooling rates in metals is to increase strength, hardness, toughness, machinability, and ductility. Unlike metals, the effects of cooling rates on polymer composites are not well understood and documented. The complex microstructural changes which they undergo right from the manufacturing process to the point of operation, mean that better understanding as to how the input parameters employed during the manufacturing process determine their microstructural construct, and hence physical and performance characteristics. During this study, HDPE gears were injection moulded using optimised input parameters which were obtained using a robust design of experiments based on the Taguchi method. These parameters were then held constant, while gears were produced at 22°C, 34°C, 50°C, and 65°C. The gears were grouped according to the mould temperature setting at which they were produced. Differential scanning calorimetry (DSC) analysis was carried out for the different temperature settings to ascertain how crystallisation was affected. The results showed lower crystallisation levels for the lower mould temperatures, and higher levels for the higher mould temperatures. Gears produced at the same mould temperature were then meshed in a uniquely designed gear test rig. Torque loadings of 0.5 Nm, 1 Nm, 2 Nm, 3 Nm, and 4 Nm were applied at 500 and 1000 rpm, and were run until they failed. A bespoke data logging system was used to record rotational cycles verses wear, and corresponding wear curves were produced. SEM analysis was then carried out to ascertain the topological mode of failure for gears produced at different mould temperatures. The presented results show a direct relationship between the different mould temperatures and the resultant microstructural changes, gear characteristics, and performance. Based on these wear rate responses to the application of varying torque loadings, a Mould to Torque Reference Chart for HDPE is presented

WTC2005-63076 THREE-DIMENSIONAL THERMAL FIELD IN SLIDER BEARINGS

ABSTRACT A three dimensional thermohydrodynamic lubrication model which couples the Reynolds and energy equations is developed. The model uses the streamline upwind Petrov-Galerkin (SUPG) method to solve the nonsymmetric stiffness matrix that results from the convective-dominated flow. Model results indicate that the peak temperature is not on the mid-plane surface, a fact that cannot be predicted with two dimensional models. This position shifts towards the mid-plane as the width to length ratio is reduced from ten to one (square slider) as well as when pressure boundary conditions are altered in such a way that the inlet/outlet pressure is higher than the side pressure. The square slider has a peak temperature 4°K less than the wider slider. This is due to the higher side flow in the square slider. INTRODUCTION Slider bearings are widely used in applications such as mechanical seals, plain collar thrust bearings, machine tool guides, and piston rings. They have good load-carrying capacity, excellent stability and durability. Investigation of the thermal effect leads to a better understanding of the load-carrying capacity. Recent studies of thermohydrodynamic lubrication (THDL) slider models include the work of Rodkiewicz [1], Schumack [2], and Kumar et a