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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Environmental management strategy : Krantzkloof Nature Reserve, a case study.

Seaman, Paul. 31 January 2011 (has links)
KZN Nature Conservation Services budgetary cuts for the KrantzkloofNature Reserve (KNR) has led to economic shortfalls in important areas like facilities maintenance and invader plant control. The study has found that the benefits of maintaining KNR, determined from the estimated Total Economic Value (TEV), are huge and far outweigh the budget shortfall. The shortfall has been closed by user charging, the timing of which has prevented any deterioration in the facilities and ecology ofKNR due to budget cuts. Facilities maintenance needs to be prioritized to protect the user charge funding base and alien invader control needs to be prioritized due to escalating costs and the magnitude of the problem. The study has found that subcatchment stakeholder groups in the developing Emolweni forum, within which KNR is strategically placed, are strongly associated with local conservancies which will essentially provide the backbone for the envisaged forum. In order for stakeholder groups to be more representative, however, it is important for local conservancies to fmd a way to draw in community groups not normally involved in conservation work. The forum should provide networking and support for projects like environmental education, income generation and rehabilitation that will allow these community groups to participate in conservation work in a meaningful way. Delivery should occur through strategically placed community institutions like schools and clinics and should target young people and the unemployed. Nature reserves have largely untapped resources and a quasi- option value project is explored that combines alien vegetation control with the development of an indigenous nursery in an ecological and economic sustainable manner. It is envisaged that income derived from the sale of horticultural plants may substitute the income derived from medicinal plants and thus reduce the pressure applied on KNR's threatened resources by the unemployed. The study recommends that the subcatchment be divided into manageable units, based on a situational analysis, out of which particular criteria and objectives can be developed. Surveys, inventories, mapping and research activities should be carried out, with reports on the state or use of soil, water and biota submitted to the forum, which can then provide management solutions. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2006.
42

A systems approach to investiging the effectiveness of using a web portal to enhance information sharing in the Ugandan construction industry.

04 May 2011 (has links)
Over the last fourteen years the construction industry in Uganda has experienced an annual average growth rate of 7.8%, markedly higher than the national GDP of 5.5%. However, the disparity bet construction information and the lack of an organised system of sharing it betwweeneen industry partners has resulted in the poor performance of construction projects. This is due to the fact that it is inadequate, inaccurate and inconsistently disseminated. This research project investigated the effectiveness of using a web portal to enhance information sharing in the Ugandan construction industry. The work is meant as a step towards the establishment of a web portal for the industry. It is envisaged that the web portal will improve construction project planning and management through the provision of basic construction information. The study population consisted of 233 construction and consulting firms. A multi-method approach was employed in the research. This included the conducting of a questionnaire survey of 80 (Le. sample size) firms, and an interview survey of 9 representatives of key stakeholders in the industry. A systemic approach was used to elicit the perspectives of stakeholders in the industry and to develop a holistic view of the research problem. The results of the research have shown that the Ugandan construction industry participants have adequate IT infrastructure and Internet access capacity to benefit from the web portal. 97% of t~e participants have computers and 77% are connected to the Internet. 83% consider the web portal to be an effective means of sharing information and 93% are willing to share the information produced by their organisations. During the study, two conceptual models (a user's information needs model and a data flow model for stages of a construction cycle) were developed and validated by six experts in construction industry practices and communication. The research underscores the fact that the successful implementation of the web portal will not only depend on the "hard" (or technical) factors but also on the "soft" (or people) factors, such as changing the users' thinking and methods of work, developing trust and building partnerships amongst participants. In essence, the project proposes the establishment of a building information centre to house and coordinate the web portal and,its related activities. / Thesis (M.Sc.ConstrMgt.)-University of KwaZulu-Natal, Durban, 2005.
43

A universal method for assessing intrinsic expansiveness of soils.

January 2004 (has links)
Many of the attempts made over the past six decades to find a universal system for assessing expansiveness of soils using soil index data have failed to follow the basic principles of soil mechanics. By overcoming most of these limitations Gourley and Schreiner (1993a) developed a new procedure that allows comparison of intrinsic expansiveness of soil samples prepared to have stable micro-fabric and consistent stress history. In this research, the same procedure is used on twenty-seven natural clayey soil samples of varying geological, geomorphological and geographical origin obtained from Kenya, Sudan, Eritrea and South Africa. Each of these samples was tested for Atterberg limits, volume change behaviours and soil suction. Statistical analysis was conducted on different soil parameters derived from these tests to obtain a significant relationship with their intrinsic expansiveness using measured swell. The analysis confirmed that most of the significant relationships obtained contain swell index, C*5' showing the identicalness of the soil properties responsible for volume change behaviour of both saturated and unsaturated clayey soils. Depending on the cost and the significance, the analysis recommended three major models that can be used as a screening system in the assessment of intrinsic expansiveness. For any soil it is possible to obtain preliminary information regarding its intrinsic expansiveness using the cheapest of the recommended models that needs liquid and plastic limit tests and hydrometer analysis, which are the routine tests of geotechnical site investigation. A more detailed assessment can be achieved by including only t he shrinkage test. The most reliable assessment needs addition of consolidation test with the unloading stage. All of the models allow obtaining information regarding the intrinsic expansiveness of soils as early as site investigation stage for successful engineering design. Moreover, they are anticipated to promote worldwide exchange of information regarding these problematic soils. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2004.
44

Investigation into the denitrification of high strength landfill leachate using pine bark and raw and composted commercial garden refuse as a carbon source : column studies.

Browne, A. J. January 2010 (has links)
Landfill leachate, the liquid discharge from Municipal Solid Waste (MSW) landfills, is the combination of the surface runoff and ground water that percolates through the waste and the liquid contained in the waste itself and is considered to be toxic and presents a potential harm to the environment. Raw leachate contains high concentrations of biodegradable and non-biodegradable carbon as well as high concentrations of ammonia nitrogen. Traditionally, landfill leachate has been treated biologically through aerobic processes which reduce the biological carbon to carbon dioxide and biomass (bacterial growth) and ammonia nitrogen to nitrates. Unfortunately this is not sufficient to protect the environment from harm. It is necessary to further treat the leachate anaerobically to transform the nitrates to elemental nitrogen which is removed from the leachate as nitrogen gas. Biodegradable carbon is often the rate limiting substrate as carbon is consumed during the preceding nitrifying phase. Biodegradable carbon can be supplemented through the addition of methanol, at great expense Leachate from the Mariannhill Landfill site is currently treated aerobically in a sequencing batch reactor where nitrification is achieved. The nitrified leachate is then used as a dust suppressant on the current site. It is anticipated that in 2012 the Land fill site would have reached capacity thereby eliminating the need to irrigate and leaving the site with an excess of nitrified leachate that will present an environmental risk. The denitrifying performance of raw commercial garden refuse, pine bark and composted garden refuse as a growth medium and carbon source was investigated through the establishment of batch and column tests. CGR Raw proved the most successful of the three growth media, achieving full denitrification at a loading rate of 1700 mg NO3-N/kg of substrate/day. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2010.
45

A linear catchment model for real time flood forecasting.

Sinclair, D S. January 2001 (has links)
A linear reservoir cell model is presented which is proposed as a good candidate for real time flood forecasting applications. The model is designed to be computationally efficient since it should be able to run on a P.C and must operate online in real time. The model parameters and forecasts can be easily updated in order to allow for a more accurate forecast based on real time observations of streamflow and rainfall. The final model, once calibrated, should be able to operate effectively without requiring highly skilled and knowledgeable operators. Thus it is hoped to provide a tool which can be incorporated into an early warning system for mitigation of flood damage, giving water resources managers the extra lead-time to implement any contingency plans which may be neccssary to ensure the safety of people and prevent damage to property. The use of linear models for describing hydrological systems is not new, however the model presented in this thesis departs from previous implementations. A particular departure is the novel method used in the conversion of observed to effective rainlfall. The physical processes that result in the rainfall to runoff conversion are non-linear in nature. Most of the significant non-linearity results from rainfall losses, which occur largely due to evaporation and human extraction. The remaining rainfall is converted to runoff. These losses are particularly significant in the South African climate and in some regions may be as much as 70-90 % of the total observed rainfall. Loss parameters are an integral part of the model formulation and allow for losses to be dealt with directly. Thus, input to the model is observed rainfall and not the "effective" rainfall normally associated with conceptual catchment models. The model is formulated in Finite Difference form similar to an Auto Regressive Moving Average (ARMA) model; it is this formulation which provides the required computational efficiency. The ARMA equation is a discretely coincident form of the State-Space equations that govern the response of an arrangement of linear reservoirs. This results in a functional relationship between the reservoir response constants and the ARMA coefficients, which guarantees stationarity of the ARMA model. / Thesis (M.Sc.Eng.)-University of Natal, Durban, 2001.
46

Influence of the degree of waste pre-treatment on carbon emissions' production and nature.

Asah, Miranda Kahndi. January 2007 (has links)
This study was carried out to gain knowledge of the degradation processes in an anaerobic environment of pre-treated waste for different degrees of pre-treatment and the evolution of waste pre-treatment by forced aeration. Pre-sorted MSW (MSW) was pretreated by composting for 16 weeks in a laboratory scale using forced aeration. Oxygen concentrations were maintained at 15-18% of oxygen in air for the first 8 weeks and 10-15 % for the later 8 weeks. The ambient temperature was kept constantly between of 20-35 QC. Representative samples of waste from the reactor were collected every fortnight wherein analysis and full characterisation on the solid matter (C/N ratio, TS and VS, R17, Biogas) and on the eluate (BOO, COD, TOC, TKN, Conductivity, pH, NOx and NH3)) were conducted. The process showed a sharp increase in temperature in the first 6 weeks, ranging from 30- 70 QC indicating a period of high biological activity, a decrease from day 30 to day 50 from 70 to 30 QC and a consistent decrease throughout the later days of the process from 35-25 QC. The sharp increase in temperature signifies a period of maximum biological activity, where readily biodegradable material decomposes as well as some of the resistant materials pointing out the success and efficiency of the forced aeration process. For the first 25 days in an anaerobic environment, waste pre-treated for four weeks was the most active, indicated by a large volume of gas produced. For the MSW pre-treated for 8, 10, 12 and 16 the volume of gas produced remained basically similar throughout the length of the experiments. CH4 production in an anaerobic reactor shows an increasing trend for all degrees of stabilisation up to 6 weeks, after that the gas production and quality deceases and is comparable to the remaining degrees of treatment. A gradual decrease in concentration of key parameters (organics) analogous to the European limit in Europa (1998), were observed after 5 weeks pre-treatment. The study highlighted that the highest efficiency of pre-treatment is achieved in 6 to 8 weeks and, therefore it is not recommended to prolong the treatment any further. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2007.
47

Monitoring the health of the rivers of the Durban Metropolitan Area using fresh water invertebrates. A pilot study.

Nunkumar, Shamilla. January 2002 (has links)
This document is aimed at all parties involved with conservation, planning and management of rivers within the Greater Durban Metropolitan Area, South Africa. The intentions of this study were to provide information on the health of the rivers using freshwater invertebrates and to identify areas where investigative efforts should be focused. In doing so, this document incorporates two data processing methods or techniques used in biomonitoring, the South African Scoring System (SASS) Rapid Bioassessment Technique (RBA) version 4 and the Integrated Habitat Assessment System (IHAS version 2c). The history, current status and future prospects and potential benefits of biological indicators both globally and in South Africa are reviewed and discussed. The RBA (SASS4) involved the standardised collection of samples using the "kick and sweep" technique from defined habitat types at representative sites on river stretches using a standardised net following defined methods. The total score per site is calculated for each family represented in the sample, which is then summed to give the SASS4 score. Lower scores are given to families with a high level of tolerance for polluted waters. The Average Score Per Taxon (ASPT) computation is obtained by dividing the SASS4 total by the number of taxa (families) in the sample. Both scores were considered when determining water quality impairment. The number and abundance of the different taxa and the number of biotopes present were considered as other measures of the river condition. The presence of numerous families of highly tolerant organisms (sludge worms and leeches) usually indicated poor water quality as represented in the Umlaas River, iSiphingo River, Tongati River, and the Ohlanga River. Several different types (or taxa) of stoneflies, mayflies and caddisflies (higher biodiversity) indicated a healthy site for example the iLovu River. Moderate river sites were characterized by declination in invertebrate diversity. Invertebrate diversity declines as the degradation of water quality increases. The manner in which SASS4 scores varied with "degree of anthropogenic impact" showed that the assessment does yield results, which follow water quality changes, provided that when SASS4 scores are less than 50, little attention is given to ASPT. At intermediate and high impacted sites ASPT did not follow habitat quality. However at low impacted water quality sites both SASS and ASPT tended to be greatest where habitat quality was the best. This study has identified that water quality "appears" to have a greater effect on macro invertebrate communities than the physical habitat and SASS distinguished sites with differing levels of water quality. This method was not designed to enable the exact nature of the disturbance to be determined, and it was intended that once an impairment of water quality had been established, it would be further assessed via intensive chemical and other studies. The use of more ecological indicators for example the inclusion of IHAS (version 2c) allowed a more comprehensive assessment of river health and more confidence could be linked to the outcome. / Thesis (M.Sc.Eng.)-University of Durban-Westville, 2002.
48

Development of sounding equipment for the assessment of the time- settlement characteristics of recent alluvial deposits when subjected to embankment loads.

Jones, Geraint Alan. January 1992 (has links)
The whole of this thesis is my work unless specifically indicated to the contrary in the text, and has not been submitted in part or in whole to any other University. Some thirty years ago the author operated a deep sounding machine, one of the first in the country, on a misty lake in Ireland and marvelled at the way subsoil information could be garnered. The magic of the moment never entirely passed and when the opportunity arose to use the technique in Natal the die was cast. The development of the national road system surged in the early 1970's and since many of these roads on the Natal coastal routes crossed extensive recent alluvial deposits, the geotechnical problems of instability and settlement became major factors in the road design. Traditional methods of investigation consisted of boreholes with sampling and laboratory testing. Whilst these were satisfactory, provided they were of adequate quality, they were relatively expensive if sufficiently detailed models of the subsoil were to be obtained for design purposes. Cone penetration testing provided a potential a solution and this led to research work conducted over a period of twenty five years which continues today. The initial development of ideas for improvements to the mechanical equipment took place whilst the author was carrying out preliminary investigations for freeway routes over the coastal alluvial deposits. This was followed by a period devoted largely to cone penetration testing research and deVelopment and to embankment design methods at the National Institute for Transport and Road Research, and to the initial registration for a Master's degree under the supervision of Professor K Knight in 1975. This research programme was completed as originally envisaged, but not submitted because during its course the author conceived the idea of the piezometer cone. This proved to be such an exciting prospect that the research and development continued for a number of years until piezometer cone testing has now become almost routine for geotechnical investigations on alluvial deposits. In 1983, due to Professor Knight's retirement from the University, Mr Phillip Everitt was appointed as the supervisor. At that stage piezometer testing was becoming accepted internationally and new aspects and information frequently appeared. It was apparent, however, that the essential proof of the system for the prediction of embankment performance was to use it at embankments where the performance had been monitored. Eventually grants were provided by the Department of Transport for this, which enabled two research projects to be conducted during 1989 - 1990 and 1991 - 1992. After completion of the first of these a presentation of the author's work on cone penetration testing since the mid 1960's was made to the Faculty of Engineering at the University of Natal. The Executive Committee of the University Senate subsequently approved, in August 1991, that the registration be upgraded to doctoral status. Mr Everitt's encouragement during this extended period has been a vital factor in ensuring an outcome for this task and the author wishes to express his gratitude for this. / Thesis (Ph.D.)-University of Natal, Durban, 1992.
49

Development of sounding equipment for the assessment of the time- settlement characteristics of recent alluvial deposits when subjected to embankment loads.

Jones, Geraint Alan. 31 March 2014 (has links)
Many embankments on the soft, highly variable, recent alluvial deposits along the South African coast have suffered large settlements necessitating ongoing costly repairs. Due to the soft variable soils, borehole sampling is difficult and laboratory testing requires to be extensive for adequate subsoil modelling; cone penetration testing was considered to be a potential means to overcome these problems. Twenty five years ago in South Africa, as elsewhere, cone penetration testing equipment was relatively crude and the methods of interpretation were simplistic. The application of cone penetration testing to recent alluvial deposits therefore required improvements to both the equipment and the derivation of soil parameters. The equipment was upgraded by introducing strain gauge load cells capable of measuring cone pressures in soft clays with adequate accuracy. Hence, correlations of cone pressures with compressibility and shear strength became possible. Predictions of settlement times and magnitudes are of equal importance and a consolidometer-cone system was developed to assess both of these. A piezometer was incorporated into a cone to ascertain whether the settlements were due to consolidation. The piezometer cone performed so well that it superseded the consolidometer-cone and by 1977 a field piezometer cone was in regular use. Developments in piezocone interpretation have taken place concurrently with those in equipment; coefficients of consolidation are evaluated from pore pressure dissipations, and soils identified from the ratio of pore and cone pressures. These developments have been validated in two recent research projects, by comparing measured and predicted settlements at eleven embankments monitored for up to fifteen years. The data shows that for embankments on the recent alluvial deposits the constrained modulus coefficient, am is : am = 2,6 ± 0,6 The data also shows that coefficients of consolidation from piezometer cone dissipation tests are correlated with those from laboratory tests and back analysed embankment performance as follows : Embankment c = 3 CPTU c = 6 Lab cv It is concluded that piezometer cone penetration testing is particularly suitable for the geotechnical investigation and the subsequent design of embankments on recent alluvial deposits and should be considered as complementary to boreholes with sampling and laboratory testing. The existing database of embankment performance should be expanded with particular emphasis on long term measurements and on thorough initial determination of basic soil parameters / Thesis (Ph.D.)-University of Natal, Durban, 1992.
50

The role of waste data in changing behaviour : the case of the South African waste information system (SAWIS)

Godfrey, Linda Keren. January 2011 (has links)
The South African waste information system (SAWIS) developed and implemented by the Department of Environmental Affairs in 2006, provided a unique case study to explore the research question “Can the collection of data for a national waste information system change the way waste is managed in South Africa, such that there is a noticeable improvement?” The research adopted an inductive approach, incrementally constructing a conceptual model of the knowledgeable, situated waste actor, through observation and hypothesis-building and -testing. The thesis draws on theory from the fields of environmental information disclosure, science communication, environmental education, and environmental psychology, in an effort to understand and contextualise the influence of waste data and knowledge on waste behaviour. Two empirical studies were undertaken in 2006 and 2011. The studies explored whether SAWIS could create opportunities beyond simply being a tool for data collection, by building the waste knowledge of those persons tasked with the responsibility of collecting and reporting the data. The thesis posited that this new knowledge could lead to changes in personal behaviour and ultimately changes in the way organisations manage their waste. While Miller & Morris’ (1999) theoretical framework of learning provided a useful means of interpreting the 2006 data, the results showed the theoretical framework to be overly simplistic for understanding the role of waste data in a developing country context such as South Africa, in that it did not account for all of the evidence gathered, particularly the existence of behavioural and situational influences. The preliminary theoretical framework was expanded in the 2011 empirical study by including Ajzen’s (1985) theory of planned behaviour. Situated within a pragmatic paradigm, the research adopted a mixed-methods research approach, making use of both quantitative and qualitative methods. The results showed that of the three constructs of knowledge (experience, data, and theory), experience currently has the greatest influence on building waste knowledge, nearly twice that of data/information and three times that of theory. Together the three variables (experience, data, and theory) account for 54.1% of the variance in waste knowledge. Knowledge is shown to have a significant influence on all three of the antecedents to behavioural intention – attitude, subjective norm and perceived behavioural control. Furthermore, perceived behavioural control, and not intention, has the greatest influence on waste behaviour, with the model accounting for 53.7% of the variance in behaviour. Respondents from public and private waste organisations represent two distinct sub-groups in the data set, subject to significantly different influences and behaviours, creating two local models. The theoretical framework accounts for 47.8% of the variance in behaviour in the municipal local model, and 57.6% of the variance in behaviour in the private local model. By applying the combined learning-behaviour theories, the results showed that there are only three regressors that currently have a significant effect on waste behaviour, viz experience, knowledge and perceived behavioural control. Two important conclusions were reached by combining the learning-behaviour theories. First, that there are obstacles that hinder the translation of intention into behaviour in the South African context, which suggests that good waste management practice is not always under the volitional control of those tasked with its implementation. Second, that there are significant differences in the way waste knowledge and behaviour are constructed, which suggest that there are underlying social forces that shape waste behaviour and that these forces may be different in public and private waste organisations. Recognising the influence of both societal structures and agency, the theoretical framework was further expanded by embedding the two linear learning-behaviour theories within Giddens’ (1984) theory of structuration. The conceptual model of the knowledgeable, situated actor developed through this research, provides a means of understanding these barriers to action and the societal context within which waste management takes place in South Africa. From the results it is clear that a tension exists between the national neo-liberal, capitalist economic structures which support a pro-growth paradigm, and the political structures which support a pro-poor social paradigm. Furthermore, this tension plays out within a country undergoing political and organisational transformation post-1994. These structures directly influence the way waste is managed. This research proposes that by understanding the way in which knowledge and behaviour are constructed, and the societal context within which this takes place, it is possible to identify practical interventions that will lead to an improvement in the way waste is managed in South Africa. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2011.

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