Interim : Interdisciplinary Journal - Volume 4, Issue 1, 2005
Volume 4, Issue 1, 2005
Author F.C. AggenbachtSource: Interim : Interdisciplinary Journal 4, pp 1 –12 (2005)More Less
This article looks at the role that vacuum casting plays in the rapid prototyping and rapid manufacturing process. The accuracy to which components can be reproduced, by looking at the controllable factors in the casting process and the different types of materials that are available, were investigated and the process was also compared to other rapid prototyping and manufacturing processes in terms of cost effectiveness. Castings were made from a typical component under different operating conditions and the characteristics of the cast component, dimensions strength and surface hardness, were measured and plotted to determine the characteristics and accuracy of the process.
Author D.J. De BeerSource: Interim : Interdisciplinary Journal 4, pp 13 –22 (2005)More Less
Atkinson distinguishes between four types of prototypes, categorised through its end-use: <ul><li>Design or aesthetic prototypes </li><li>Geometrical prototypes </li><li>Functional prototypes </li><li>Technological prototypes</li></ul>Shigley and Mitchell define the design process according to the following six phases: <p>Recognition of need <br>Definition of problem <br>Synthesis <br>Analysis and optimization <br>Evaluation <br>Presentation <p>The Centre for Rapid Prototyping and Manufacture (CRPM) of the Central University of Technology, Free State was asked to assist in the development of a newly developed gynaecological cream applicator. Apart from needing a freeform fabrication system to give form fit and function to the very complex design, the product needed Rapid Tooling / Rapid Manufacturing support to enable a first batch production for medical trials and evaluation. The paper will descriptionbe the total product development process alongside prototype categories descriptionbed by Atkinson and design phases defined by Shigley and Mitchell (including some iterations enabled through timeous prototyping, including various Rapid Prototyping (RP) Technologies, soft tooling and vacuum casting). More importantly, results from Rapid Tooling for limited run production (due to the complexity of the product the cycle time of the Prototype Tool is fairly long), as well as the economical impact made possible through the support of CAD / CAM and RP Technologies, will be discussed.
Author J. Du PreezSource: Interim : Interdisciplinary Journal 4, pp 23 –33 (2005)More Less
The improvement of the efficiency and cooling capacity of a simple vortex tube is considered. Three Ranque-Hilsch Vortex tubes, with different diameters and lengths, were developed and manufactured. The vortex tube is an unique device with no working parts and has the ability to deliver hot and cold air simultaneously. It is a simple, low cost device, which is easy to manufacture. Different orifice sizes and nozzle configurations are designed and manufactured to investigate the performance of the three vortex tubes. The <SPAN lang lang=AF style=""FONT-FAMILY: Symbol; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-char-type: symbol; mso-symbol-font-family: Symbol""><SPAN style=""mso-char-type: symbol; mso-symbol-font: Symbol"">f</SPAN></SPAN> 22 mm vortex tube with a <SPAN lang lang=AF style=""FONT-FAMILY: Symbol; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-char-type: symbol; mso-symbol-font-family: Symbol""><SPAN style=""mso-char-type: symbol; mso-symbol-font: Symbol"">f</SPAN></SPAN> 7, 5 mm orifice and small diameter nozzle gave a better efficiency and an increase in the drop in temperature of the cold air against the different inlet pressures. The maximum efficiency of the <SPAN lang lang=AF style=""FONT-FAMILY: Symbol; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-char-type: symbol; mso-symbol-font-family: Symbol""><SPAN style=""mso-char-type: symbol; mso-symbol-font: Symbol"">f</SPAN></SPAN> 22 mm diameter vortex tube improved from 8, 9% against a cold fraction of 0, 630 (with the <SPAN lang lang=AF style=""FONT-FAMILY: Symbol; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-char-type: symbol; mso-symbol-font-family: Symbol""><SPAN style=""mso-char-type: symbol; mso-symbol-font: Symbol"">f</SPAN></SPAN> 6 mm x 2 tangential nozzle block) to 18, 92% against a cold fraction of 0, 644 (with the <SPAN lang lang=AF style=""FONT-FAMILY: Symbol; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-char-type: symbol; mso-symbol-font-family: Symbol""><SPAN style=""mso-char-type: symbol; mso-symbol-font: Symbol"">f</SPAN></SPAN> 3 mm x 4 tangential nozzle block) at an inlet pressure of 500 kPa. The maximum drop in temperature of the cold air improved from 27, 0 <sup>o</sup>C against a cold fraction of 0, 120 (with the <SPAN lang lang=AF style=""FONT-FAMILY: Symbol; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-char-type: symbol; mso-symbol-font-family: Symbol""><SPAN style=""mso-char-type: symbol; mso-symbol-font: Symbol"">f</SPAN></SPAN> 6 mm x 2 tangential nozzle block) to 42, 3 <sup>o</sup>C against a cold fraction of 0, 284 (with the <SPAN lang lang=AF style=""FONT-FAMILY: Symbol; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-char-type: symbol; mso-symbol-font-family: Symbol""><SPAN style=""mso-char-type: symbol; mso-symbol-font: Symbol"">f</SPAN></SPAN> 4 mm x 2 tangential nozzle block) at an inlet pressure of 600 kPa.
Source: Interim : Interdisciplinary Journal 4, pp 34 –49 (2005)More Less
The concept entrepreneurship can be defined as the ordinary individual who does extraordinary things which other ordinary individuals hesitate to do. The act of doing is a distinctive element of the entrepreneur. <br>Considering the level of unemployment, the shortage of housing, uneven distributions of wealth and income, low level of education and high population growth rate in South Africa, the entrepreneur can play a major role. Entrepreneurs must equip themselves with knowledge, skills and the right attitude. <br>In this article the focus is on various entrepreneurs to understand the world of entrepreneurship better.
Source: Interim : Interdisciplinary Journal 4, pp 50 –64 (2005)More Less
It is important for any organization to do a competitive analysis before entering a specific market. There are three components in the market environment: consumers, competition, and suppliers. <br>Hand in hand with competition as one of the components in the market environment goes the concept ""competitive edge"". If an organization has an competitive advantage that organization have something that other organizations do not have. If no competitive advantage can be identified, the new organizations will not be able to satisfy current needs in the target market. The following article address competition as a tool to fight competition.
An assessment model in outcomes-based education and training (OBET) for Health Sciences and Technology in South AfricaAuthor M.M. NelSource: Interim : Interdisciplinary Journal 4, pp 65 –79 (2005)More Less
The study addresses a concern in higher education and specifically in Health Sciences and Technology regarding integrated and authentic assessment with an outcomes-based approach. From the information generated, an assessment model is proposed for application in Health Sciences and Technology. By applying the Delphi technique, a validated assessment model is presented for assessment in outcomes-based education and training in Health Sciences and Technology. The process and product of the research should add value to the assessment of learning in the outcomes-based approach in higher education with specific reference to Health Sciences and Technology.
Catchment management-model evaluation : verifying data for the implementation of the water release module of the WAS programAuthor N. BenadeSource: Interim : Interdisciplinary Journal 4, pp 84 –92 (2005)More Less
The Water Administration System (WAS) is designed to be a management tool for irrigationschemes and water offices that want to manage their water accounts and supply to clientsthrough canal networks, pipelines and rivers. The ultimate aim of WAS is to optimizeirrigation water management and minimize management-related distribution losses inirrigation canals. This research project focus on the implementation of the water releasemodule of the WAS program at the Vaalharts irrigation scheme. WAS consists of fourmodules that are integrated into a single program that can be used on a single PC, a PCnetwork system (in use currently at Vaalharts) or a multi-user environment. These modulescan be implemented partially or as a whole, depending on the requirements of the specificscheme or office. The four modules are an administration module, a water request module;water accounts module and a water release module. The first three modules are alreadyimplemented at Vaalharts, while module four is implemented only partially. This modulelinks with the water request module and calculates water releases for the main canal andall its branches allowing for lag times and any water losses and accruals. Any researcher inthis field should first understand where water comes from and how it will be utilized beforeany calculations are attempted. Only then manipulation of the release volume cancommence. To precisely calculate this water release, accurate data is needed to ensurethat the correct volume of water is released into the canal network. This can be done byverifying existing data with field data. To optimize the management of the irrigation schemethe fully implemented WAS program need to be installed and running at the scheme. Aseries of data and calculation verification needs to be executed. The exercise will show theadequacy and correctness of the available database WAS uses to do the releasecalculation from. This will ensure improved management of the irrigation scheme,catchment and water resource sustainability. It is planned that the information generatedfrom this project will be used in the compilation of an integrated catchment managementinformation system, currently underway in the school of Civil Engineering and BuiltEnvironment at the Central University of Technology, Free State, South Africa.
The relationship between body mass index, energy intake and level of physical activity of HIV positive women (25-44 years) in MangaungAuthor Z. HattinghSource: Interim : Interdisciplinary Journal 4, pp 93 –102 (2005)More Less
<I>Objective:</I> To determine the relationship between body mass index (BMI), energy intake and levels of physical activity of HIV negative and HIV positive women. <br><i>Design:</i> Cross sectional study. <br><i>Methodology:</i> A random sample of 500 pre-menopausal women within the two age group categories of 25-34 and 35-44 years was selected. Data on physical activity was obtained using an adapted Baecke questionnaire and categorized into low, medium, and high levels of physical activity. Weight and height were used to calculate BMI. Dietary intake was determined by means of a standardized food frequency questionnaire. <br><i>Results:</i> Sixty-one percent of younger women and 38% of older women were HIV infected. The vast majority of women (91%) had low levels of physical activity, while only 9% of the sample had physical activity levels that fell within the normal to high category. More than 50% of respondents were either overweight or obese (BMI above 25 kg/m<sup>2</sup>). BMI of HIV positive younger women was, however, significantly lower than that of HIV negative women. Median energy intakes were high (more than 10 000 kJ) for both HIV positive and HIV negative women. <br><i>Conclusions:</i> Reverting to a more traditional lifestyle, including diet and physical activity, could assist in addressing unfavorable BMI parameters of these women and improve health status and quality of life of HIV infected women.
Author Liezel LuesSource: Interim : Interdisciplinary Journal 4, pp 103 –123 (2005)More Less
This article reviews the perspectives on the rights, roles and endeavours of women in the South African work environment. In an attempt to achieve this objective, the article commences with a holistic approach on the evolution of women's rights and roles. The remainder gives perspectives on the South African labour force and finally outlines the importance of South African legislation on the advancement of women. The situation of African women is, in particular referred to, as it was evident during 1995 and earlier that African females were considerably under-represented in various sectors of the workforce. African women were, for example, introduced into the management environment as recently as the 1980s, while supportive legislation only came into place in the 1990s.
Author Henriette OberholzerSource: Interim : Interdisciplinary Journal 4, pp 124 –131 (2005)More Less
Student Counseling is very important to the well being of the students. The purpose of thisresearch is to investigate students' attitudes and perceptions regarding counselingservices offered to help them to adjust to academic and social demands at tertiary level.<br>A qualitative study was done through semi-structured interviews and surveyquestionnaires. A representative sample was drawn from the 1500 students at theinstitutions. The analysized data indicated that the students in this study were relativelyoptimistic about seeking counseling and about the positive effect of counseling offered. Itis however recommended that the counselor should be more available for emergencies -which implicated more staff and better advertisement of the services available.
Author F.E. Van SchalkwykSource: Interim : Interdisciplinary Journal 4, pp 132 –142 (2005)More Less
The primary aim of the study was to assess the effect of a nutritional supplement on the clinical conditions of HIV-positive/AIDS patients using standard procedures. This clinical trial comprising 35 patients consisted of a baseline visit and three months of nutrient supplementation from April to September 2003. At baseline, pre-study examinations of the patients were done and patients who satisfied the inclusion criteria were included in the study. At baseline, the physical and clinical conditions of the patients were noted and reported by a physician. <br>This was followed by nutrient supplementation for three months under adequate supervision. The physical and clinical examinations were repeated monthly and at the end of the study. It is believed that the supplement probably played a contributory role in improving the clinical conditions, improvement on the physical appearance and quality of life. However, the positive effects of the supplement on the clinical conditions of the patients cannot be confirmed in this study. This is because the patients were also treated for different clinical conditions during the course of supplementation. Further studies are needed to confirm the effect of the supplement. The study was limited by small sample size, short duration of study and the late stage of HIV infection of the patients.
Author L.J. BarnardSource: Interim : Interdisciplinary Journal 4, pp 143 –148 (2005)More Less
The possible use of Rapid Prototypingi related technologies to support medical product development for cancer patients was investigated. The hypothesis is to use CAD / CAM / RP related technologies to substitute infected bone regions through the use of CT to CAD to .STL manipulation. The work is done in collaboration with a group of surgeons and biomedical engineers to concurrently model replacement bone regions, using data obtained through CT scans, and translated to either CAD or .STL format. This will then be used as input data to model replacement bones. The paper will descriptionbe methods used; formats, results obtained thus far, difficulties and further potential, such as the development of practice material and special cases for surgeons.
Author M.I. VenterSource: Interim : Interdisciplinary Journal 4, pp 149 –163 (2005)More Less
For many organizations, success with Business Intelligence (BI) requires a coordinated effort across the dimensions of people, processes, technology and data. The complexity of ""real-world"" BI applications continues to grow with the increasing demand for information at all levels of a business. In the maze of potholes many BI efforts fail to impress, are abandoned or are not even completed. Fortunately, a number of best practices and techniques have been developed to achieve the mission of BI - while overcoming these key implementation challenges. This article defines BI, examines the core reasons for BI failure as well as some key methods used to overcome these obstacles.
Author G. JordaanSource: Interim : Interdisciplinary Journal 4, pp 164 –175 (2005)More Less
This paper gives an overview of the current and proposed research inautomated industrial processes performed in the School for Electrical andComputer Systems Engineering at the Central University of Technology,Free State. The aim with the research initiative is the development ofrelevant skills and expertise in automated, remote monitoring and control ofmanufacturing installations and processes. The primary activity in thiscontext is the provision of a research platform by means of which staff andstudents can develop research skills in practical process control in apseudo-manufacturing environment.
Author C.H. WesselsSource: Interim : Interdisciplinary Journal 4, pp 176 –188 (2005)More Less
To achieve the national objectives of equitable and sustainable social and economicdevelopment, strategies and institutional arrangements for water resourcesmanagement must be developed by water boards. There are also specific requirementsin the National Water Act (NWA) for water resources management activities to supportthe provision of water services. Many challenges face water resource managers inensuring that these national objectives be met and to be compliant with therequirements set by the NWA. Neither the resources nor the time required to addressthese objectives should be underestimated.<br>The fundamental bases of any water strategy/planning is water demand forecasting. Toaccomplish this, the need for a framework for the implementation of a Water DemandManagement Model (WDMM) was identified. Through focus group discussions withBloem Water and literature studies on water models the necessary features for aframework for a WDMM was identified. This was compared with the features of adecision support systems framework that yield many similarities.