Interim : Interdisciplinary Journal
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Open Access journal
ISSN (Print) 1684-498X
Published by Sabinet Online Ltd [188 journals]
- Effects of illumination on accessibility of public parks in South African
Authors: J. Honiball; D. Das
Abstract: Public parks (PP) and open recreational facilities are essential elements in cities particularly in the residential areas. Evidence from literature suggests that PPs have a positive influence on the social and physical health of the people who have access to them. Although, PPs have been located in the residential areas of South Africa according to urban planning guidelines and rules, they are observed to be underutilised. Many factors including location, accessibility, and social issues like crime or fear of crime, life style, and lack of time are generally attributed for such a scenario. Therefore, the objective of this study is to explore how illumination levels in the public parks influence the utilisation of public parks in the residential areas of South African cities. The investigation was conducted by using Bloemfontein city as a case study following a survey research method. The study revealed that more people use the PPs during evening hours, higher illumination is one of the most important factors that contributes to the accessibility of the PPs in the residential areas and the utilisation of parks are enhanced with higher level of artificial illumination.
- Cost-benefit analysis of recloser placement for reliability
Authors: J. Pretorius; C.T. Gaunt
Abstract: Technical network reliability in electrical distribution networks and the improvement thereof will always be part of utilities and the electricity supply industry. One of the key reliability improvement strategies is additional recloser (breaker) installation on medium voltage networks.The effect of recloser placement on network reliability is investigated. A method of cost-benefit analysis (CBA) is explored, explained and used to analyse the placement of additional reclosers in electrical networks. Costs and benefits are shown to be different when viewed from the perspective of the utility against that of the customer, and this ultimately influence the placement of a newly planned breaker.
- Examining the relationship between abstract thinking ability and academic
performance in object oriented programming : a psychometric and
theoretical analysis of student capacity
Authors: M. Kompi; L. Grobbelaar
Abstract: reasoning involves flexible thinking as well as solving problems creatively and logically. Evidence suggest that especially first year students that undertake Information Technology studies at institutions of higher education, find it challenging to successfully comprehend concepts regarding object oriented programming (OOP). This study is based on the hypothetical premise that student performance regarding OOP can be linked to the abstract thinking ability of the particular student because of the highly abstract nature of OOP concepts. A comparison between psychometric test results gauging abstract thinking abilities of students and student performance in OOP are also presented and argued.
- Optimum strategic management system for Lesotho roads network through
Authors: Md.A. Al-Hussain; M.M. Hassan
Abstract: The paper presents the application of World Bank's Model RONET to optimize strategic management system for Lesotho roads network. The Lesotho road network condition deteriorated considerably during the 2000s due to underfinancing of operations and maintenance. In recent years, as the financial situation in Lesotho has improved, financing for the road sector has gradually increased, focusing on the most hazardous and highly trafficked parts of the road network. However, the overall budget allocated to the sector remains inadequate to maintain the entire district road network in a stable condition. This research is going to present the application of World Bank's model Road Network Evaluation Tool (RONET) to strategic network level analysis of the Lesotho road network. The goals of the presented study are to obtain the optimum maintenance and rehabilitation strategy and related budget, estimate the impact of different funding levels on the future quality and estimate the economic consequences of budget constraints.The application of RONET model will lead to an optimal maintenance and rehabilitation strategy with a good balance between rehabilitation, periodic and recurrent maintenance. The implementation of optimal maintenance and rehabilitation strategy would cause major improvement compared to current condition of the network. Implementation of higher than optimal maintenance and rehabilitation leads to substantially higher roads directorate costs and consequently lower net benefits, while the implementation of the lower than optimal maintenance and rehabilitation standards would lead to considerably worse network condition for slightly lower agency costs. This means that even minor budget constraints would result in considerably higher total road transport costs in the country's economy.
- Capacitive coupling on overhead power lines
Authors: M. Van Der Mescht
Abstract: This paper contains research performed on the effects of capacitive coupling on overhead power lines under loss of phase conditions in an earthed system. The research was triggered by a contact incident which occurred on a 11kV overhead line during unplanned maintenance performed under live conditions.
- Environmental effects of road pavements stabilized with Class F fly ash
Authors: M.W. Heyns; M.M. Hassan
Abstract: Fly Ash is a residue generated by coal combustion and abundantly available, but due to potentially toxic elements found in Fly Ash, is considered harmful to the environment. The objective of this study is to evaluate the environmental effects of fly ash used as a stabilization agent in road pavement construction. Using laboratory-testing specimens of fly ashes namely, Kendal Dump Ash, Durapozz and Pozzfill, stabilized with classified G5 material and 1% AFRISAM and LAFARGE cement respectively and leach testing done to evaluate chemical leach properties over time and the harmful effects it has on the environment. Laboratory leaching sample results have indicated that Fly Ash constituents exhibit limited mobility. The study revealed that Fly Ash is an environmental option and has engineering advantages when used properly for soil stabilization techniques.
- Validating the optimum tilt angle for PV modules in the central region of
South Africa for the winter season
Authors: P.E. Hertzog
Abstract: Optimizing the output power of any PV module involves a number of factors, including the setting of the tilt angle. The purpose of this paper is to present empirical evidence validating the optimum tilt angle for PV module installations in semi-arid regions of South Africa for the winter season. The experimental setup includes three identical PV systems where the PV modules where set to different tilt angles as stipulated in the literature. Data was recorded from May to July 2015 using an Arduino board and LabVIEW software. Two power measurements were used to validate the optimum tilt angle as being Latitude plus 10° for the winter season.
- A mechanism for lean and sustainability : the case of infrastructure
projects in South Africa
Authors: R.B. Isa; F.A. Emuze D.K. Das
Abstract: Stakeholders in the construction sector are placing a much stronger emphasis on the importance of attaining sustainability within the industry. While much efforts has been deployed towards attaining sustainable development through infrastructural projects, the methods used by most stakeholders for projects procurement hinders the attainment of criteria for sustainability. The proposed research will thus explore how to evolve a mechanism for promoting lean sustainable construction with infrastructure projects in South Africa. The study is primarily to assess the components of the framework required for the integrative implementation of lean and sustainability concepts in an infrastructure project. The study is qualitative in nature, based on interpretative theoretical framework that is grounded in literatures in the field of built-environment. Emergent findings indicate that a case study approach and specifically, qualitative comparative analysis (QCA) research approach provide answers to the research questions, which are domiciled in a complex socio-technical environment. The evolution of the mechanism shall focus on lean construction and sustainability methods / tools that support the elimination of wastes in work processes, work methods, work culture and materials issues, thereby promoting energy and resource efficiency. It is expected that the framework that will leads to continuous improvement in the areas of energy and resource efficiency, minimization of emission (Co2) from the built environment, improvement in stakeholders working relationships and social benefits to the community, among others.
- Multiple vision inspections from a single control system using vision
Authors: T. Bihi
Abstract: The development of a Machine Vision system involved the selection of various components that will work together in order to solve a vision problem. The vision system was tasked with verifying reconfiguration and the position of devices within the assembly system, as well as inspecting the product for defects that infringe on its quality. The aim in this article is to discuss the control and setup of the multiple vision inspections that the vision system had to perform in order to solve the assembly systems verification and quality assurance problem.
- Geotutor : software created as an educational resource for geotechnical
Authors: W. Badenhorst; E. Theron
Abstract: Innovative software applications may prove to be advantageous in a teaching environment. It has been proven that technological teaching produces better achievement in class and an increased interest in the relevant field of teaching. Software that is able to produce a basic geotechnical report will give civil engineering students an insight into the field of geotechnical engineering and an understanding of the relevant inputs required and the outputs generated. A fundamental understanding of site investigations and related reports is an important aspect of geotechnical engineering training.
- Implications of population parameters in predicting periodic tendencies
within an age-structured population model with a Shepherd recruitment
Authors: Michelle Heidi Ellis
Abstract: Designing an age-structured population model requires knowledge of the interaction between age and time related phenomenon within population. Data from life tables can be used to estimate the survival and birth rates needed in the design of an age-structured model.
- An algorithm for calculating the evolutionary stable strategy for an
age-structured population model with a Shepherd recruitment function
Authors: Michelle Heidi Ellis
Abstract: An algorithm for calculating the evolutionary stable strategy for an age-structured population model with a Shepherd recruitment function
- A mechanism for waste reduction in structural design process in South
Authors: A. Aka; F.A. Emuze D.K. Das
Abstract: Structural design process (SDP) consists of three processes of inception; preliminary design and detail design. Each of these processes is laden with wastes that adversely affect project performance. Therefore, this study seeks to identify such wastes so as to develop a mechanism for its effective management. To achieve this, action research study will be conducted in some consulting engineering firms situated in Bloemfontein, South Africa. It is expected that the results will provide the platform for the development of a suitable mechanism for reduction / elimination of wastes in structural design process.
- Multi material powder delivering systems for selective laser melting
Authors: A. Kinnear; I. Yadroitsava I. Yadroitsev
Abstract: Selective Laser Melting (SLM) is a powder bed fusion process which is an additive manufacturing (AM) process, whereby a laser beam selectively fuses regions of a powder bed to form complex objects. Growth in the SLM field has revealed the need for parts containing multiple materials for applications in the medical, tool making, aerospace and other hi-tech industries. By applying multiple materials, regions with different mechanical properties, thermal conductivity zones or corrosion-resistant coatings can be achieved in a single manufacturing cycle utilizing the SLM process. With the SLM process physical bonds can be formed between different materials by creating an interlocking interface due to the rapid solidification of the molten materials. With the current SLM equipment, multi material objects are possible but only with material differences between the layers. New approaches are needed to develop a method that allows multi material parts not only in the Z axis, but also allow material differences on a single layer (X-Y axis). Approaches such as powder feeding through a capillary tube, auger feed system, electrostatic charge or masks have all been proposed as solutions to multi material deposition. Multi material objects produced in a single cycle with complex geometry and prescribed properties has the opportunity of further growing the AM market.
- Validating the acceptance zone for PV modules using a simplified measuring
Authors: A.J. Swart
Abstract: Optimizing the output power of any PV module involves a number of factors, including the orientation angle. However, many PV modules are not installed at the suggested orientation angle of 0° N in South Africa, thereby indicating a nonalignment to the maximum solar radiation available for a given day. The purpose of this research is to highlight the importance of this installation by validating its acceptance zone using a simplified measuring approach. Results confirm that the incident angle on a specific PV installation varies around 44° for winter months. This indicates an acceptance zone of around 88°, which must be optimally aligned to the solar radiation curve, thereby yielding the optimum amount of output power.
- Clearing of transient faults in MV networks
Authors: C.J. Van Der Mescht; W.J.D. Van Schalkwyk
Abstract: This paper contains research performed on the effectiveness of methods that aims to clear transient faults on MV networks without causing momentary supply loss to customers due to ARC operations, which is achieved by "instantaneous" interruption of fault currents. This is done by momentarily disconnecting the NECR's neutral earth connection. Currently the research also includes the implementation of single pole breakers which are able to trip independently from each other within 25ms. Implementing these methods of clearing transient faults will result in less stress being placed on breakers, joints, conductors and transformers within the MV network. It will also yield a better QoS performance with regards to dips and momentary interruptions. Lastly, the scheme will result in up to 50 times less burn wounds on people or animals in the unfortunate case of making contact with the MV network.
- The amalgamation of mechanical, electrical and software technology to
remove manual tasks performed in a vehicle rental business
Authors: D. Van Rensburg; C.H. Wessels
Abstract: Most operational businesses today are restricted to normal business hours, as it is not cost effective for a business to operate on a 24-hour basis. Not only will operational costs increase substantially, in addition to these increases, the company will be faced with numerous challenges that range from security to staffing. Over the years, technology has proven to be an asset in which businesses could invest and enjoy the rewards of their investment in the form of an increase in employee efficiency, ease of new procedural implementations and the enforcement of governance. This process of continuous refinement has resulted in business systems developing to a point where the input required from an employee has been limited to the bare minimum. With the flexibility, dependability and affordability of technology today any operational business can reduce the need for human input into their systems. This article discusses the techniques employed by the researcher to stratify the hypothesis that the amalgamating of mechanical, electrical and software technologies will remove manual tasks performed by staff in a vehicle rental business.
- Assessment of traffic congestion in the central areas of Kimberley city
Authors: D.K. Das; M.S.M. Keetse
Abstract: Traffic congestion is a challenge leading to undesirable consequences in most of the cities of the world. Many large and medium cities of South Africa, specifically the central business districts (CBD) are facing this challenge and are severely affected by this mobility problem. One such city, Kimberley, because of its unique physical, spatial, road network, economic characteristics and requirement of the mobility of heavy vehicles in addition to the normal city traffic faces typical traffic congestion challenges in its CBD area, particularly during the peak hours, which warranted this investigation. So, the objective of this paper is to assess the degree of traffic congestion (Level of Service (LOS)) in the roads of CBD area and explores a possible mechanism to ease the problem. A survey research methodology and application of relevant empirical models were employed to assess the level of traffic congestion and observe possible solutions to ease the traffic conduct this investigation. Findings revealed that there is appreciable level of traffic congestion in some of the roads of the CBD area of the Kimberley City, specifically during the peak hours, which needs strategic intervention. A reengineering solution, such as, traffic diversion from the congested roads to the underutilised or least congested roads could assist in easing the traffic congestion, increase in speed and reduction in travel time resulting into optimal utilisation of all the roads in the CBD area of the city.
- Sustainable approach to upgrade low volume roads in Petrusville
Authors: E. Mckenzie; M. Mostafa Hassan
Abstract: Research undertaken in Petrusville and Philipstown was to illustrate how nonconventional materials performed as a sub-base. Roads investigated in this research paper were classified as light or low volume roads where the daily traffic equalled to 100 vehicles per day. Main objectives was to achieve a reduction in the overall life cycle cost, vehicle operating cost and the depletion of nonrenewable resources for the roads. The outcome the road authorities and the different stakeholders wanted to achieve was that non-conventional materials can replace good quality road construction materials if the approach is cost effective and sustainable in the long term.
- Validating a reconfigurable assembly system utilizing virtual
Authors: H.J. Vermaak; J.A. Niemann
Abstract: South African manufacturing companies today need to be more sophisticated technologically to compete for global markets. The latest trend in automation and manufacturing emerges in the form of reconfigurable systems. The aim of this paper is to show the development of a reconfigurable assembly system and using virtual commissioning to plan, validate and optimize it. To achieve this "DELMIA" software was used to create a virtual simulation environment to verify an assembly cell from such a system as a case study. Simulations were conducted to verify software functions, device movements and operations, and the control software of the system. As a result, it was found that virtual commissioning is an excellent tool for predicting how the system will function, verifying system code early, and rectifying design flaws. This will enable manufacturing companies to be more competitive, ensure increased productivity, save time and ensure them an advantage over their competition.
- Residual stresses in direct metal laser sintered parts
Authors: I. Van Zyl; I. Yadroitsava I. Yadroitsev
Abstract: Direct Metal Laser Sintering (DMLS) fabricates parts using a track-by-track, layer-by-layer method in which powder is formed by melting and solidification of single tracks and thin layers. A laser beam scans over the powder layer thus creating a cross-sectional area of the 3D object. High-concentration of laser energy input leads to high thermal gradients which induce residual stress within the as-built parts. Methods for measurement residual stresses and stresses in DMLS parts were analysed.
- Extending the technology acceptance model to evaluate discussion forum
adoption in a learning management system
Authors: J. Aucamp; J. Swart
Abstract: The inclusion of ICT for educational purposes has burgeoned over the past decade. However, preliminary investigations indicate that e-learning systems remain underutilized, including systems such as discussion forums. The purpose of this study is to establish constructs that may promote adoption and use of discussion forums. The Technology Acceptance Model forms the theoretical framework for this study and is extended by including digital inclusion, perceived attention and perceived enjoyment. Thirty ICT students were purposively selected and interviewed. Findings suggest that perceived usefulness and ease along with digital inclusion may positively influence discussion forum adoption among undergraduate students.
- Perspectives of education stakeholders on the influence immediacy, verbal
aggression and compliance gaining have on learner performance
Authors: B. Fredericks; M. Van Deventer
Abstract: In South Africa the educational system has seen many changes over the past few years. Transformation in education has been introduced to correct imbalances of the previous South African educational system and to improve learner achievement in some of the previously disadvantaged schools. Despite changes that have been implemented, learners in many South African schools are still underperforming. The primary aim of this investigation reported in this article was to establish the extent to which selected micro communication factors, namely, immediacy, verbal aggression and compliance gaining influence learner achievement. The researcher argues that micro communication factors in the classroom could influence learner performance either positively or negatively. According to Robinson, learner achievement refers to the ability of a learner to succeed in an assessment and to display a satisfactory level of competence.
- The Developmental Appraisal System (DAS) as a major issue in educational
policy discourse in the Foundation Phase of schools in the Free State
Authors: A.B.M. Kolobe
Abstract: The purpose of this paper, based on a doctoral study, is to examine how teachers in the Foundation Phase of schools in the Free State province perceived, conceptualised and implemented Developmental Appraisal System (DAS) as a component of the Integrated Quality Management System (IQMS). The epistemological and ontological perspectives pertaining to both quantitative and qualitative approaches compelled the researcher to choose the Mixed Method Research (MMR). Data analysis consisted of the inferential and descriptive statistics for quantitative data analysis and, themes, patterns and behaviours for qualitative data analysis. Unbalanced two-way ANOVA, T-test and frequency distributions were used in analysis of quantitative data while themes and patterns resembled qualitative data analysis. The majority of teachers perceived DAS as a developmental process while a sizable minority claimed to the contrary. The Department of Basic Education did not provide direct training to teachers on matters pertaining to both the DAS and IQMS. Furthermore, the money reward earned through the process of DAS was perceived to be a source of conflict between teachers and school management.