The relationship between the value chain and project success in the Malawian construction industry
- Authors: Kadangwe, Samuel Ronald
- Date: 2013
- Subjects: Construction industry -- Malawi , Industrial procurement -- Construction -- Malawi
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:9715 , http://hdl.handle.net/10948/d1020865
- Description: The construction industry in Malawi plays a vital role in developing the infrastructure of the country that is in need of improvement. Thus, in order to improve the quality of infrastructure in Malawi, the construction industry has to perform better than the status quo. The construction industry is characterised by a complex value chain that comprises of clients, consultants, contractors, and material manufacturers, suppliers, financing institutions, knowledge organisations and regulatory authority. This research looks at the relationship between construction value and project success in the Malawian construction industry. A qualitative research method was used for compiling the primary data for the study. Twenty-nine (29) participants were interviewed. These participants represented clients, consultants, contractors and material suppliers. The findings reveal that value creation in Malawi is characterised by lack of harmonised standards and specifications, inconsistent project management practices, existence of non-value adding activities, corrupt practices, lack of a skilled labour force, and lack of commitment to best practices in H&S as well as environmental management. Further, logistical problems affect the supply of construction materials to the country; while an unfavourable economic environment makes pricing of materials a challenge in the country too. Poor communication and limited use of information technology (IT) is very common in the industry and project implementation is also affected by a poor road network, an intermittent power supply, and a lack of cooperation from other service providers. In terms of supply chain structures in use, the research revealed that the traditional procurement method that is based on the lowest bidder / price is the most dominant method in use and very few members of the construction industry are conversant with other procurement methods. The method is also the preferred procurement method used by public sector clients. The performance of the traditional procurement method largely depends on the competence of the project design and supervision team, the adequacy of the documentation, and the capacity of the contractor. However, in most cases the system has failed to perform due to the poor contract management skills of the supervising consultant and the lack of timely guidance from the public sector clients. The findings also revealed that most of the suppliers or subcontractors are engaged on project based relationships, and members of the industry are unwilling to engage in long terms relationships due to mistrust and greed among members of the industry, and also largely due to lack of proper frameworks that can support such relationships. It is therefore recommended that other procurement methods should be explored and the engagement of the lowest price bidders should be discontinued on small and medium scale projects. The criteria for upgrading contractors to higher categories should equally be revisited to eliminate incompetent contractors. The NCIC should take a leading role in harmonising the various standards and specifications in use in the country. Promotion of the usage IT services should be encouraged to facilitate faster information dissemination. Usage of risk management in construction and evaluation and monitoring of projects should be encouraged and benchmark best practices. Finally, the members of the industry should take up the responsibility to take leading entities in the industry to task, if fundamental changes are to take place in the industry.
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- Date Issued: 2013
The role of the sandprawn, Callichirus kraussi, as an ecosystem engineer in a temporarily open/closed Eastern Cape estuary, South Africa
- Authors: Njozela, Cuma
- Date: 2013
- Subjects: Estuarine biology -- South Africa -- Eastern Cape , Decapoda (Crustacea) -- South Africa -- Eastern Cape , Biotic communities -- South Africa -- Eastern Cape , Bioenergetics -- South Africa -- Eastern Cape , Shrimps -- South Africa -- Eastern Cape , Estuarine ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5583 , http://hdl.handle.net/10962/d1001539 , Estuarine biology -- South Africa -- Eastern Cape , Decapoda (Crustacea) -- South Africa -- Eastern Cape , Biotic communities -- South Africa -- Eastern Cape , Bioenergetics -- South Africa -- Eastern Cape , Shrimps -- South Africa -- Eastern Cape , Estuarine ecology -- South Africa -- Eastern Cape
- Description: The role of the sandprawn, Callichirus (=Callianassa) kraussi (Stebbing), as an ecosystem engineer was assessed in the lower reach of the temporarily open/closed Kasouga Estuary situated along the Eastern Cape coastline of southern Africa over the period April 2010 to June 2011. The study comprised two distinct components, a field study and a caging experiment. The field study assessed the correlation between sand prawn densities and selected physico-chemical (organic content of the sediment and bioturbation) and biological (microphytobenthic algal concentrations and macrobenthic abundance and biomass) variables in 50 quadrants in the lower reach of the estuary. Densities of the sand prawn within the quadrants ranged from 0 to 156 ind m⁻² (mean = 37 ind m⁻²). There were no significant correlations between the densities of the sandprawn and the estimates of the organic content of the sediment and the abundance and biomass of the macrofauna (P > 0.05 in all cases). Numerical analyses failed to identify any effect of the sandprawn density on the macrofaunal community structure. The rate of bioturbation was, however, strongly correlated to the sand prawn density. Similarly, the microphytobenthic alga concentrations were significantly negatively correlated to the sand prawn densities ((P < 0.05). The absence of any distinct impact of the sandprawn on the macrobenthic community structure appeared to be related to their low densities in the lower reach of the estuary during the study. To better understand the role of the sandprawn as an ecosystem engineer, a caging experiment was conducted using inclusion and exclusion treatments (n= 5 for each treatment). Densities of the sandprawn in the inclusion treatments (80 ind m⁻²) were in the range of the natural densities within the estuary. The experiment was conducted over a period of 18 weeks in the lower reach of the estuary during summer. The presence of the sandprawn, C kraussi, contributed to a significant decrease in the microphytobenthic algal concentrations and the abundance and biomass of the macrofauna (P < 0.05 in all cases). The decrease in the microphytobenthic algal concentrations in the presence of the sandprawn appeared to be related to the res-suspension of the sediments (bioturbation) generated by the burrowing and feeding activities of the sandprawn. The observed decrease in macrofaunal abundances and biomass in the inclusion treatments appeared to be mediated by both the decreased food availability (mainly the microphytobenthic algae) and the burial of organisms within the sediments. Numerical analysis indicated that the sandprawn did, however, not contribute to a change in the species composition of the macrofauna. Results of the current study indicate that C.kraussi plays an important role in structuring the invertebrate community and energy flow within temporarily/open closed Kasouga Estuary.
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- Date Issued: 2013
The sustainability of rural sanitation facilities in municipalities
- Authors: Maxwele, Zukani
- Date: 2013
- Subjects: Sanitation, Rural -- South Africa -- Eastern Cape , Sanitary engineering -- South Africa -- Eastern Cape , Sewage disposal, Rural -- South Africa -- Eastern Cape , Rural development projects -- South Africa -- Citizen participation , Municipal services -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:9713 , http://hdl.handle.net/10948/d1020580
- Description: Progress has been made in eradicating the backlog in sanitation. This is reflected by the 2011 Census results that reflect a 21 percent increase in the provision of sanitation between the 2001 Census and the 2011 Census. In the rural areas of O.R. Tambo District Municipality, the eradication of sanitation backlogs is done through the provision of VIPs for sanitation. Even with this progress, there are still challenges resulting from the previously constructed sanitation facilities. Some of the challenges relate to the poor quality of these facilities. Community members – via the IDP road shows have voiced their unhappiness with regard to some of the sustainability factors of these structures. Community members feel they were not involved in decisions related to the sanitation projects. It has also been observed that the municipality and its agents do not conduct environmental management studies; and some pits of these structures were not lined, and the health and hygiene training, together with post-construction assessment was not done. In this study, an assessment of the provision of sanitation facilities, in order to identify some of the key factors that are critical to the sustainability of rural sanitation facilities, was done. The research findings should be helpful in assisting local government to improve the provision of sanitation facilities, with the aim of ensuring sustainability, improving community satisfaction, and improving the quality of life for the people living in these villages. For the purpose of the study, a quantitative research approach was used. A research questionnaire was used to collect the data; and it was distributed through email to a sample of respondents that understood sanitation issues. The data were collected from municipal officials, consultants working on sanitation projects, as well as other stakeholders with influence and an interest in sanitation. The results were analysed to establish the findings and to propose recommendations, in order to improve the sustainability of rural sanitation facilities. From the research findings, the recommendations highlighted the need for an improved participatory approach in implementing sanitation projects. To ensure sustainability, the following issues are key: monitoring and supervision; community participation and adherence to design guidelines; a review of the sanitation provision policy; as well as the promotion of health and hygiene.
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- Date Issued: 2013
Tolerance intervals for variance component models using a Bayesian simulation procedure
- Authors: Sarpong, Abeam Danso
- Date: 2013
- Subjects: Bayesian statistical decision theory , Multilevel models (Statistics)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10583 , http://hdl.handle.net/10948/d1021025
- Description: The estimation of variance components serves as an integral part of the evaluation of variation, and is of interest and required in a variety of applications (Hugo, 2012). Estimation of the among-group variance components is often desired for quantifying the variability and effectively understanding these measurements (Van Der Rijst, 2006). The methodology for determining Bayesian tolerance intervals for the one – way random effects model has originally been proposed by Wolfinger (1998) using both informative and non-informative prior distributions (Hugo, 2012). Wolfinger (1998) also provided relationships with frequentist methodologies. From a Bayesian point of view, it is important to investigate and compare the effect on coverage probabilities if negative variance components are either replaced by zero, or completely disregarded from the simulation process. This research presents a simulation-based approach for determining Bayesian tolerance intervals in variance component models when negative variance components are either replaced by zero, or completely disregarded from the simulation process. This approach handles different kinds of tolerance intervals in a straightforward fashion. It makes use of a computer-generated sample (Monte Carlo process) from the joint posterior distribution of the mean and variance parameters to construct a sample from other relevant posterior distributions. This research makes use of only non-informative Jeffreys‟ prior distributions and uses three Bayesian simulation methods. Comparative results of different tolerance intervals obtained using a method where negative variance components are either replaced by zero or completely disregarded from the simulation process, is investigated and discussed in this research.
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- Date Issued: 2013
Towards identifying how knowledge management concepts may be applied to enhance the tendering process in South African public sector institutions
- Authors: Kasi, Sizukisa Bridget
- Date: 2013
- Subjects: Letting of contracts -- South Africa , Knowledge management , Public contracts -- South Africa , Transparency in government -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:1150 , http://hdl.handle.net/10962/d1007741 , Letting of contracts -- South Africa , Knowledge management , Public contracts -- South Africa , Transparency in government -- South Africa
- Description: The state of the Tendering Process in South African Government Institutions has become an area of concern in recent years with issues related to transparency, governance and rigid retrospective procedures being cited as impediments to efficiency. In tum, Knowledge Management (KM) and its ability to be applied to all types of organisations to increase efficiency has been popularised extensively. An analysis of KM literature suggested that the principles of KM may be used to increase efficiency and create competitive advantage. This study attempted to identify whether the benefits gained by other organisations through the application of Knowledge Management principles, could be applied to the Tendering Process in South African Government Institutions. The study sought to identify how Knowledge Value Chain by Wang and Ahmed (2005) may be leveraged to create an enhanced Tendering Process. The study then reviewed the Tendering Processes conducted in Australia, United States of America, Malaysia and South Africa and sought to identify the common steps in a tendering process in order to construct a standard tendering process. The Knowledge Value Chain was then applied to this process to create a standard tendering process enhanced by Knowledge Management Principles. The model was compared to the processes currently conducted in two Government institutions and two parastals. The findings indicated that the model is well suited for Government Organisations and would assist in the creation of greater transparency, however the practical implementation of the model is yet unlikely as the model suggest electronic access to information, and the process in South African Government Institutions is predominately paper-based.
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- Date Issued: 2013
Trends in large carnivore diets in the Addo Elephant National Park, South Africa
- Authors: Wentworth, Julia Claire
- Date: 2013
- Subjects: Game reserves -- South Africa , Carnivorous animals
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10595 , http://hdl.handle.net/10948/d1020993
- Description: Determining carnivore diets and how they may change over time is important if the management of large carnivores is successful in an enclosed reserve. Carnivore diets are known to shift over time in response to a variety of factors. These factors include prey availability and climatic conditions (rainfall patterns). The re-introduction of lions (Panthera leo) and spotted hyaena (Crocuta crocuta) to Addo Elephant National Park (AENP), South Africa provided the opportunity to study diet trends of lions and spotted hyaena in an enclosed system. The study focused on the diets and overlap of lions and spotted hyaena and how their prey selection changed since their re-introduction in 2003 to 2010. The database included scats collected over a seven year period. A total of 195 spotted hyaena scats and 217 lion scats were analysed using scat analysis. Prey items estimated from scat samples were coupled with prey availabilities to determine preferred prey items. Additionally, from determined carnivore diets, lions and spotted hyaena diet overlap was estimated over time. Lions preferred prey items which included zebra (Equus quagga) and eland (Tragelaphus oryx) during the early portion of the study. Over time preference shifted to include buffalo (Syncerus caffer), bushbuck (Tragelaphus scriptus) and grey duiker (Sylvicapra grimmia). Spotted hyaena preferred zebra and eland in the earlier part of the study, then over time, shifting their selection to grey duiker, buffalo, red hartebeest (Alcephalus busephalus) and bushbuck. Lions and spotted hyaena had a similar diet which increased in overlap during the study (67 percentage - 91 percentage). Our findings suggest that lions and spotted hyaena had a degree of diet specialization; both carnivores avoided and preferred certain prey items relative to their abundance. Their preference excluded the most abundant prey items, thus causing a decline in abundance of rarer species over time. Lions and spotted hyaena did not respond by shifting their diets to consume abundant prey items when their preferred prey items declined in availability. However, this study may be a snap-shot of carnivore’s diet trends. Thus further monitoring of the large carnivore diets should be researched in order to determine which factors drive their prey selection. Additionally, lions and spotted hyaena diet overlap increased overtime. The high diet overlap may be a result from spotted hyaena scavenging off lion kills, thus spotted hyaena diets may be facilitated by lion kills. Finally our data suggests that re-introduced large carnivores in AENP are likely to change the composition of the overall mammal community, potentially eliminating rare but preferred prey species in an enclosed reserve.
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- Date Issued: 2013
Unlocking the development of built environment professionals through infrastructure investment in South Africa
- Authors: Mputa, Nobutyani Sinethemba
- Date: 2013
- Subjects: Career development -- South Africa , Construction workers -- South Africa , Infrastructure (Economics) -- South Africa , Job security -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:9673 , http://hdl.handle.net/10948/d1020049
- Description: spending is regarded to be one of the major contributors to economic growth. The purpose of the study was to investigate how infrastructure projects could engender professional skills development. The topic is focused on a human resource (HR) perspective as it is one of the knowledge areas in project management. In order to achieve the research objectives and also establish the breadth of the subject issues in the literature review, a qualitative methodology was employed. Interviews were conducted and the majority of the participants were working towards professional registration in the built environment professions. The empirical findings that emerged from the study show that the majority of the respondents agreed that HR units should be aware of the legislation related to professional training and education. The interviewees further elucidate that, although professional registration is the primary duty of the candidate, HR units should ensure that interns are doing what is in line with their professional requirements, according to different councils, to ensure compliance. However, the lack of a structured approach in administering training programmes is a key factor that contributes to the lack of development of professional skills on government sponsored infrastructure projects. This must be addressed to attain the desired professional development outcomes among historically disadvantaged individuals (HDIs) that are keen on professional registration and development in the built environment professions. Other empirical findings showed that most of the respondents showed some concern regarding job security with their present employment. They explained that once the status of professional registration is attained, securing employment in the industry should be relatively easy. South Africa needs a highly skilled workforce to ensure growth of the economy therefore HR departments in organisation should adapt a systematic approach in their HR planning in order to ensure skills are engendered to HDIs as well.
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- Date Issued: 2013
Updating the ionospheric propagation factor, M(3000)F2, global model using the neural network technique and relevant geophysical input parameters
- Authors: Oronsaye, Samuel Iyen Jeffrey
- Date: 2013
- Subjects: Neural networks (Computer science) , Ionospheric radio wave propagation , Ionosphere , Geophysics , Ionosondes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5434 , http://hdl.handle.net/10962/d1001609 , Neural networks (Computer science) , Ionospheric radio wave propagation , Ionosphere , Geophysics , Ionosondes
- Description: This thesis presents an update to the ionospheric propagation factor, M(3000)F2, global empirical model developed by Oyeyemi et al. (2007) (NNO). An additional aim of this research was to produce the updated model in a form that could be used within the International Reference Ionosphere (IRI) global model without adding to the complexity of the IRI. M(3000)F2 is the highest frequency at which a radio signal can be received over a distance of 3000 km after reflection in the ionosphere. The study employed the artificial neural network (ANN) technique using relevant geophysical input parameters which are known to influence the M(3000)F2 parameter. Ionosonde data from 135 ionospheric stations globally, including a number of equatorial stations, were available for this work. M(3000)F2 hourly values from 1976 to 2008, spanning all periods of low and high solar activity were used for model development and verification. A preliminary investigation was first carried out using a relatively small dataset to determine the appropriate input parameters for global M(3000)F2 parameter modelling. Inputs representing diurnal variation, seasonal variation, solar variation, modified dip latitude, longitude and latitude were found to be the optimum parameters for modelling the diurnal and seasonal variations of the M(3000)F2 parameter both on a temporal and spatial basis. The outcome of the preliminary study was applied to the overall dataset to develop a comprehensive ANN M(3000)F2 model which displays a remarkable improvement over the NNO model as well as the IRI version. The model shows 7.11% and 3.85% improvement over the NNO model as well as 13.04% and 10.05% over the IRI M(3000)F2 model, around high and low solar activity periods respectively. A comparison of the diurnal structure of the ANN and the IRI predicted values reveal that the ANN model is more effective in representing the diurnal structure of the M(3000)F2 values than the IRI M(3000)F2 model. The capability of the ANN model in reproducing the seasonal variation pattern of the M(3000)F2 values at 00h00UT, 06h00UT, 12h00UT, and l8h00UT more appropriately than the IRI version is illustrated in this work. A significant result obtained in this study is the ability of the ANN model in improving the post-sunset predicted values of the M(3000)F2 parameter which is known to be problematic to the IRI M(3000)F2 model in the low-latitude and the equatorial regions. The final M(3000)F2 model provides for an improved equatorial prediction and a simplified input space that allows for easy incorporation into the IRI model.
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- Date Issued: 2013
Uptake of liposomes into bacterial cells
- Authors: Oidu, Benjamin
- Date: 2013
- Subjects: Liposomes , Drug carriers (Pharmacy)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10165 , http://hdl.handle.net/10948/d1021010
- Description: Liposomes are small phospholipid vesicles that have been widely investigated as drug carriers for the delivery of therapeutic agents. A variety of liposome formulations are presently under clinical trial exploration, while others have already been approved for clinical use. The aim of this study was to optimize liposome uptake into bacterial cells. Both gram-positive and gram-negative bacteria were used in the study as well as Candida albicans.Response surface methodology (RSM) using a central composite design (CCD) model was used to optimize liposomal formulations of carboxyfluorescien (CF) for each of the three microbes, and also the three microbes in combination namely; Staphylococcus aureus (Sa), Escherichia coli (Ec) and Candida albicans (Ca). Percentage of CF encapsulated and CF increase in Uptake were investigated with respect to two independent variables that were, cholesterol (CHOL) and stearylamine (SA) content. Design Expert 8 was used for the purpose of finding the combination of independent variables that would yield an optimal formulation for each microbe and the three microbes in combination. The model selected by the software managed to reasonably correlate the predicted models to the experimental data. Encapsulation of carboxyfluorescien (CF) into a liposome formulation enhanced its uptake by Staphylococcus aureus and Escherichia coli as well as Candida albicans. This was evident in the increase in CF uptake when the uptake rate of free CF was compared with that of liposomal CF.
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- Date Issued: 2013
Voltammetric investigation of microbiological growth media and carbon nanotube modified electrodes : a case study of oxytetracycline
- Authors: Kruid, Jan
- Date: 2013
- Subjects: Voltammetry , Electrodes , Oxytetracycline , Carbon nanotubes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4156 , http://hdl.handle.net/10962/d1018238
- Description: Oxytetracycline (OTC) is a broad spectrum antibiotic used extensively in the agricultural and human-health sector, and is effective against various gram positive and –negative bacteria as well as large viruses and certain pathogenic Rickettsiae. This study addresses the lack of voltammetric knowledge regarding the electroanalytical characterisation of OTC and its analysis in complex matrices. Cyclic voltammetry (CV) revealed several irreversible anodic peaks for OTC at a bare glassy carbon electrode (GCE). These current responses were improved through the selection of a diluent for OTC stock preparation, electrolyte solution and electrolyte pH, stir time and applied preconditioning potential. Under enhanced adsorptive conditions and using square wave voltammetry (SWV), a detection limit of 24.3 nM was achieved. The electrode surface could be renewed in vitro for 10 successive scans. OTC oxidation was characterised as a one electron:one proton ECiE mechanisms. Next, investigating the viability of voltammetry in various complex microbiological growth media revealed that selected growth media contained interfering redox active components, which, while simultaneously coating the electrode surface, effectively reduced GCE performance and lowered the active electrode surface area, as ascertained through CV and electrochemical impedance spectroscopy (EIS) studies. This interference lowered OTC current response in the presence of growth media which was partially recovered by appropriate growth media selection and sample dilution. In testing the use of acid functionalised multi-walled carbon nanotubes (MWCNTs) to improve anodic OTC response, charge-based attraction was observed between the MWCNT dispersal agent Nafion® and OTC, while increased surface area associated with prolonged acid functionalisation time aided in improving OTC current response.
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- Date Issued: 2013
Weather neutral models for short-term electricity demand forecasting
- Authors: Nyulu, Thandekile
- Date: 2013
- Subjects: Electric power consumption -- Forecasting -- Mathematical models , Forecasting -- Mathematical models
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10578 , http://hdl.handle.net/10948/d1018751
- Description: Energy demand forecasting, and specifically electricity demand forecasting, is a fun-damental feature in both industry and research. Forecasting techniques assist all electricity market participants in accurate planning, selling and purchasing decisions and strategies. Generation and distribution of electricity require appropriate, precise and accurate forecasting methods. Also accurate forecasting models assist producers, researchers and economists to make proper and beneficial future decisions. There are several research papers, which investigate this fundamental aspect and attempt var-ious statistical techniques. Although weather and economic effects have significant influences on electricity demand, in this study they are purposely eliminated from investigation. This research considers calendar-related effects such as months of the year, weekdays and holidays (that is, public holidays, the day before a public holiday, the day after a public holiday, school holidays, university holidays, Easter holidays and major religious holidays) and includes university exams, general election days, day after elections, and municipal elections in the analysis. Regression analysis, cate-gorical regression and auto-regression are used to illustrate the relationships between response variable and explanatory variables. The main objective of the investigation was to build forecasting models based on this calendar data only and to observe how accurate the models can be without taking into account weather effects and economic effects, hence weather neutral models. Weather and economic factors have to be forecasted, and these forecasts are not so accurate and calendar events are known for sure (error-free). Collecting data for weather and economic factors is costly and time consuming, while obtaining calendar data is relatively easy.
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- Date Issued: 2013