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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.
1

Accumulation and toxicity of lead in soil along the road verges in the City of Cape Town

Kruger, Anne-Liese January 2007 (has links)
Thesis (MTech (Environmental Health)--Cape Peninsula University of Technology, 2007 / The widespread use of lead (Pb) and especially Pb from vehicular emissions arising from lead additives in petrol has resulted in high levels of this metal found in various soil samples taken along the road verges of Cape Town CBD. The accumulation of lead was investigated in roadside surface soil by collecting soil samples at various sites along the three major highways (N7, N2, N1), approximately three metres from the road verges and at a depth of approximately 5 cm for a period of 12 months. After digestion with 55"70 nitric acid the Pb concentrations were determined by using an Inductively Coupled Plasma Atomic Emission Spectrophotometer (ICP-AES). Results have shown the Pb concentrations in the soil at busy intersections to be higher than at other areas along the roadsides. Lead concentrations found in the roadside soils of the N1 ranged between 200 and 2000 mg/kg and these were of the highest concentrations found compared to the other two highways and were even higher than found in other studies. The roadside soils on the N1 highway, with the most traffic, according to car count data obtained, seemed more contaminated than the other two highways. It was also investigated whether earthworms (Eisenia fetida) accumulated Pb after being exposed to the contaminated soil from the sampling sites. The earthworms in the highly contaminated soil accumulated on average much higher concentrations of Pb than the earthworms in the lower Pb contaminated soil. A potential biomarker (cell membrane integrity) was applied to determine whether the earthworms experienced toxic stress as a result of the exposure to lead contaminated soil. Behavioural and morphological changes in the earthworms were also observed. The Trypan blue exclusion assay was used to measure the effect of lead exposure on the membrane stability of the coelomocytes in the coelomic fluid of earthworms. In the highest exposure groups per highway, a significant decrease in percentage viable cells were seen (N7, 36 ± 0.07%; N2 48 ± 0.09%; N1, 34 ± 0.08%). The fact that clear statistically significant responses were seen after the five week exposure period in the highest, as well as lowest exposure groups indicate that these responses could serve as an early warning system of lead exposure. The percentage cell viability (biomarker) used in this study have been useful in identifying toxic stress in earthworms caused by lead in roadside soils. The additional information obtained by using biomarkers could not be obtained by chemical analysis of soil and earthworms alone.
2

The effect of South African provincial road condition on the efficiency of forest product transport

Nicholls, Stephen John 03 1900 (has links)
Thesis (MScFor)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: The context of the study is concern over declining provincial road condition due to insufficient government funding of road maintenance. These roads are by their public nature used by a wide variety of commercial and private interests contributing a variety of axle loads. There was no information available on the use of these roads by forest companies and the road conditions. Consequently a survey was conducted to determine condition and length of each segment of provincial road in use by forestry companies and the volume of wood transported over them. In addition data was gathered on other users and their contribution to the volume transported over each section. The questionnaire indicated that the provincial roads are in a poor state. The literature review suggested a significant reduction in total cost of transport can be achieved by maintaining or rebuilding these roads. South African forest companies provide the majority of the heaviest axle loading to these roads and must theretore take responsibility tor damage caused to them. Also a variety of forest companies use the same roads and consequently collaborative studies between companies are needed. A modified Dijkstra's algorithm was used to quantify the effect of the condition of South African provincial roads on the efficiency of the transport ottorest products. The model requires digitised raster road and forest map layers combined with transport vehicle specification as input. The products of the model are optimum routes from all source points to a single exit point or sink, the total volume transported across all road nodes and the total cost to extract all wood from a map section. This output allows managers to identify critical roads tor management attention and make tentative estimates of possible reductions to total cost by altering the road condition. The manager is able to test the sensitivity of the solution to changes in variables and gain a better overall picture of the interactions within the system. The model results, and improved understanding, will provide input to more specific and collaborative studies. South African forest managers can respond to the poor provincial road network by conducting ad hue maintenance to these roads to prevent them becoming completely impassable or to rebuild them to their design state and maintain them at that state. The cost of taking no actions is that these roads would eventually become impassable. The road network model determined that, for the study area, a unilateral decision to rebuild and maintain all roads would result in a net increase in transport costs ofR 2 million/year. When compared to the cost of ad hue road improvements for the same area of R 8 million it is obvious that proper road management is a better option. It was shown that 75% of the reduction in total cost is generated by improving only 31 % of the provincial road surface. Consequently, by improving selected roads (20% of the total provincial road network for the area) it was possible to generate a net cost R 2.9 million lower than if the roads were left as they are. If reductions in operating costs are included the net cost to the forest industry is R 3.1 million/year lower than leaving the roads as they are. In addition to the cost being lower, an improved road network would be in place and the current ad hue spending would be unnecessary. On a larger scale it was estimated that poor provincial road management costs the industry as a whole R 26 million or R 1.52/m3/year. This money can be used to offset the costs of maintaining and upgrading roads. It is therefore concluded that the South African forest industry needs to assess its policy on provincial road management and become more active in the managing of these roads. The tool developed and presented is intended as a prototype decision support tool in developing future policies. / AFRIKAANSE OPSOMMING: Die inhoud van hierdie studie handelaar die verval van provinsiale paaie as gevolg van die regering se onvoldoende fondse vir die instandhouding van die paaie. Hierdie paaie word as gevolg van hulle publieke aard deur 'n wye verskeidenheid kommersiële en private belange gebruik, wat bydra tot 'n verskeidenheid van asladings. Daar was geen inligting oor die bosbou maatskappye se gebruik van paaie of die toestand van die paaie beskikbaar nie. Gevolglik is 'n opname gemaak 0111 die kondisie en lengte van elke segment van die paaie wat deur die bosbou maatskappye gebruik word, vas te stel, asook die volume hout wat oor die paaie vervoer word. Data oor ander verbruikers van die paaie is verder ingesamel, asook hul bydrae tot die volume wat oor die paaie vervoer word. Die vraelys het aangedui dat die provinsiale paaie in 'n baie swak toestand is. 'n Literatuurstudie het getoon dat 'n beduidende daling in die totale vervoerkoste moontlik is deur hierdie paaie te onderhou afoor te bou. Die Suid-Afrikaanse bosbou maatskappye voorsien die meerderheid van die swaarste asladings op hierdie paaie en moet dus verantwoordelikheid neem vir beskadigde paaie, 'n Verskeidenheid bosbou maatskappye gebruik die paaie; gevolglik is gesamentlike studies tussen die maatskappye ook nodig. 'n Aangepaste Dijkstra algoritme is gebruik om die effek van die toestand van Suid- Afrikaanse provinsiale paaie op die effektiwiteit van die vervoer van bosbou produkte, vas te stel. Hierdie model benodig digitale inligting oor die hoofen bosbou paaie, asook die spesifikasies van die voertuie wat gebruik word. Die resultaat van die model is die optimale roetes vanaf alle bronpunt oorspronge tot by 'n enkele bestemming, die totale volume vervoer oor al die padnodusse en die totale koste verbonde aan die verwydering van alle hout uit 'n afgemerkte seksie op die kaart. Hierdie produk of result ate stel bestuurders in staat 0111 kritieke paaie vir aandag te identitiseer en om tentatiewe voorspellings van moontlike afname in die totale kostes te maak indien die toestande van paaie verbeter sou word. Die bestuurder kan die sensitiwiteit van die oplossing vir variasie in die veranderlikes toets en sodoende 'n beter geheelbeeld kry van die interaksie binne die sisteem. Die resultate van die model en n beter begrip daarvan, kan insterte lewer in meer spesitieke studies en gesamentlike studies tussen maatskappye. Suid Afrikaanse bosbou bestuurders kan teen die swak provinsiale padnetwerk optree deur ad hoc instandhouding toe te pas op hierdie paaie om te voorkom dat hulle totaal en alonbegaanbaar word. Ofhulle kan die paaie restoureer tot hul oorspronklike toestand en hulle dan in stand hou. Die kostes daaraan verbonde om nie op te tree nie, is dat hierdie paaie uiteindelik on-gaanbaar sal word. Die padnetwerkmodel het gewys dat vir die spesitieke studie area, 'n eenparige besluit 0111 alle paaie te herbou en onderhou, 'n algehele toename in vervoerkostes van R2 miljoen/jaar tot gevolg sal hê. Wanneer dit vergelyk word met die R8 miljoen wat die ad hoc padverbeterings kos, is dit duidelik dat geskikte padbestuur 'n beter opsie is. Daar is bewys dat 75% van die daling in totale kostes genereer kan word deur verbeteringe aan die oppervlaktes van slegs 31% van die provinsiale paaie te maak. Gevolglik was dit moontlik om netto kostes van R2,9 miljoen ruinder te genereer as vanneer geen instandhouding gedoen is nie. Dit is bewerkstellig deur verbeteringe aan geselekteerde paaie aante bring (20% van die totale provinsiale padnetwerk vir die area.) As die daling in bedryfskoste ingesluit is, sal die netto koste vir die bedryf R3.1 millioen/jaar ruinder wees as om die paaie so te los sonder enige aandag. Verder, tot laer koste sal daar 'n verbeterde pad netwerk in plek wees en die huidige ad hoc spandeering aan die paaie nie meer nodig wees nie. Op groot skaal, is die benaderd voorspelling dat 'n swak provinsialepadbestuurstelsel die bosbou bedryf R26 millioen of R 1.52/m3 uit die sakjaag. Hiedie misbruikde geld kan eerder teruggeploeg word in pad onderhoud en opgradeerings werksaamhede. Dit is dus nodig dat die bosbou bedryf sy beleid weer in oonskou moet neem in verband met die bestuur van provinsiale paaie en ook meer aktief die voortou sal moet neem in die instandhoudind van provinsiale paaie. Die metodiek hier ontwikkel kan 'n inleidende doel dien in die ontwikkeling van toekoemstige besluit neeming rakend die bestuur van provinsiale paaie.
3

Modification of black cotton soil using a mixture of fly ash and slagment for road construction.

Maneli, Andile. January 2014 (has links)
M. Tech. Civil Engineering / Black cotton soils are fertile and very good for agriculture, horticulture, sericulture and aquaculture. However, they are not good as road construction material because of their undesirable engineering properties and, therefore, need to be removed from site or modified to meet the minimum design standards required for roads subgrade material. This type of clay is very expansive and causes significant damages and problems on South African roads. Roads that are built on expansive clays are adversely affected by the behaviour of the expansive clay. Conventional methods of road design and construction over such material has proved to be very costly. It has been a practice in road construction to remove black cotton soil and replace with better quality soil. This results in high construction costs. The use of by-product and waste materials for modification and stabilization of engineering properties of expansive clays has environmental and economic benefits. On the other hand, problematic material may be treated in its natural state "in situ", thereby leading to reduction in cost. Thus, the modification of Black cotton soils using a mix proportion of fly ash and slagment may improve the engineering properties of the material. The overall objective of the study was to investigate and determine the appropriate mix proportion of fly ash and ground granulated blast furnace slag in the modification of engineering properties of black cotton soil for use in road construction.
4

An evaluation of subjective road classification terminology through interaction models

Marijnen, Michelle 31 July 2012 (has links)
M.Ing. / South African road infrastructure has developed as product of various influences such as growth in traffic demand, economic and social demand, policies and imperatives, access needs and political ideologies and pressures. A country needs to revisit their road classification model on regular bases to ensure these influences are addressed. This support ensures sustainable economic and social growth in a region. Road classification models internationally and nationally use non-quantified terminology to classify road classes. Terminology such as “key towns” or “important towns” is commonly used. These terms creates misleading interpretations by authorities and transportation planners. This study developed a method to define road classification classes based on the economic activity and social interaction between origin and destination towns. The outcome is to eradicate the non-quantified terminology use in road classes.
5

Evaluation of the effectiveness of public participation in the Gauteng electronic tolling programme

24 April 2015 (has links)
M.A. (Public Management and Governance) / The South African road system is managed by the South African National Roads Agency Limited (SANRAL), which is an agency under the Department of Transport. The main aim of SANRAL is to connect major cities, towns and emerging villages. It has undertaken a project of upgrading and expanding of the road network in the Gauteng Province of South Africa, known as the e-tolling system. It allows for the free flow Electronic Tolling (E-Toll) system and records all vehicles passing through the tollgate without requiring them to stop or slow. A built-in device (tag) is fitted into the overhead gantry system to detect the passing vehicle, which reads an e-tag (if fitted), as well as recording the number plate of the vehicle. A fee for using the road will be charged and paid later from a registered e-toll account, linked to the vehicle user or if no e-tag is present a bill is submitted to the owner. The primary issue associated with the project relates to complaints from various interest groups, political parties and civic organisations regarding public participation in the planning and execution of e-tolling. This has resulted in mass marches and court cases, with the project, consequently undergoing delays, suspension and postponements. The study is, thus, motivated by the foregoing factors in endeavouring to assess the effectiveness of the public participation process in the initial stages of the e-tolling project. The research utilised an exploratory case study method; comprehensively appraising the public participation areas within the e-tolling project of Gauteng. The study employed both documentation reviews and interviews as data collection methods. The research design was predominantly qualitative, however data analysis was undertaken and presented in both qualitative and quantitative evaluations...
6

An exploratory study of rationales influencing roads and route choices of private car owners : case study : Bisley, Pietermaritzburg.

Makhoba, Mzwandile. January 2011 (has links)
Roads are a significant element of modernity. They are not only sites that facilitate mobility and fluidity needed for modern capitalist economy but also spaces which signify the social relations formed within the system. This conceptualization of the road is central to the project at hand. The aim of this research is to unpack factors influencing route choices of private car owners in the Bisley area in Pietermaritzburg in terms of their primary activities (going to work, shopping etc.) and what socio-political contents inform and frame these rationales. Additionally, this research explores the extent to which crime influences spatial consumption and mobility patterns. The research made use of qualitative approach that sought to interrogate the contexts within which what is considered rational choices are made and provide insight into how private car owners in Bisley area contextualize their decision. In-depth interviews with individuals (owners of private car) from various households in Bisley were conducted. The findings reveal that drivers use routes that provide them with the maximum positive outcomes, and consider their options within multiple factors as they arise out of the conditions on each road and each trip. The study also found variations in terms of the mode of rationality used in situational contexts and their multiplicity. For example, morning traffic prompted the drivers to use instrumental rationality; whereas travel during other parts of the day was not restricted to this form of rationality. The findings of study also in some ways support already existing view that there is a link between spatial consumption and perceptions of crime; however, this requires further interrogation of this theme with systematic data collection appropriate to it. Most importantly consideration of safety on the road definitely shapes decisions of the research participants on which roads and routes to frequent, and at which time of the day. Furthermore, the study through the tracing of participants‟ movements using maps shows the ways in which class and race feature on the roads of the country. The study argues that class rather than race is re-spatialized in post-apartheid South Africa. This was attributed to recent socio-political and economic dynamic developments taking place in South Africa, where the black majority is becoming more affluent. / Thesis (M.Soc.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.
7

Geomorphic considerations in the deterioration of rural roads : the case of Inkandla, Indwedwe and Ga-Modjadji.

Khandlhela, Nkhensani. January 2003 (has links)
The condition of the rural road network in South Africa is in a severe state of deterioration and remains a matter of concern for inhabitants of rural areas. Apart from heavy use, the main problem is that road development is often neglected and the main focus is placed on the geomorphic environment. The objective of this study is to identify the nature of the geomorphic constraints of vehicular access on unarmoured roads in the rural areas of KwaZulu Natal and the Limpopo Province of South Africa, and to gain a better understanding of how these function. It is hoped that some of the insights gained can then be used to inform policy decisions regarding the location and design of rural roads in the future. In this study, a number of unarmoured roads were studied in detail to identify the possible environmental constraints on vehicular access. A number of soil physical and chemical properties were used to examine the state of road degradation. These properties included particle size analysis, soil strength, Cation Exchangeable Capacity and Exchangeable Sodium Percentage. The results of the investigation of soil properties have shown that they play a significant role in road degradation. The major geomorphic factors involved in road deterioration include soil type, soil erosion and precipitation characteristics, mass movements, slope conditions and human activity. The physical characteristics, especially the soil and slope conditions, make the access roads in all study areas susceptible to soil loss. Factors such as geology, drainage and friable soils vulnerable to mass movements have been identified as seriously constraining vehicular access. Soil erosion problems in the study area are largely the result of physical and chemical properties of soils combined with steep gradients and have been identified as the primary cause of road degradation. It was further found that the socio-economic conditions, together with the anthropogenic influences such as the construction of rural access roads on vulnerable slopes, population density and the removal of vegetation cover in all the study areas have significantly enhanced road deterioration. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.
8

Partnering with suppliers for quality improvement

Baliso, Unathi January 2010 (has links)
A dissertation submitted in fulfillment of the requirements for the degree Master Technology: Quality in the Faculty of Engineering at the Cape Penisula University of Technology / Uneven surfaces on national roads that often lead to difficulty and even danger can be extremely hazardous when wet, due to mud and cracks, and also create dust pollution for motorists, pedestrians, residents and business. The continuing use of low quality raw materials in producing hot mix asphalt for national roads, leads to regular maintenance at a very high cost. The quality aggregates (stone that is used to produce asphalt), and the quality of bitumen are often inadequate for the correct composition of hot mix asphalt. The mst important factors affecting initial and long term performance of the highways is the inferior pavement structure and condition, due to poor aggregates (raw material)from suppliers. The performance of asphalt i s largely determined by the characteristics of its constituents, the asphalt binder and aggregates.
9

An assessment of e-tolling as a method of financing Gauteng roads

Ponter, Lloyd Anthony January 2015 (has links)
E-tolling was recently implemented on roads in Gauteng, South Africa. This gave rise to a great deal of protest by road users and a court battle between the South African National Roads Agency (SANRAL) and the Opposition to Urban Tolling Alliance, a body representing road users. The e-tolling system was criticised at various levels and on numerous grounds, some financial and others appearing to be emotional. This thesis attempted to analyse the various grounds for objection against the system, the main goal of the research being to analyse e-tolling in Gauteng to ascertain whether or not the introduction of e-tolling was justified or whether an alternative method of taxation to pay for the upgrading of Gauteng roads would have been more cost-effective. Secondary data in the form of documents from multiple sources was used in the analysis, including an Economic Impact Assessment that was one of the key inputs into the decision to introduce e-tolling. It was found that there are multiple problems plaguing the e-toll system and e-tolling is not the most cost-effective taxation method of paying for Gauteng roads. Using a fuel levy or general tax revenue available to the National Treasury were both found to be more cost-effective methods as they would have achieved the same result (repairing and upgrading specific Gauteng roads), at a cost of R20,0913 billion less than e-tolling. It was suggested that the best taxation method/s to pay for the roads would have been using a fuel levy and general tax revenue as the primary funding methods, with vehicle licensing fees and long distance toll roads as secondary methods to aid the primary methods.
10

Investigation of the effect of selected polypropylene fibres and ultra-fine aggregate on plastic shrinkage cracks on South African roads

Kluyts, Grant January 2005 (has links)
Plastic shrinkage cracks, although not inherently structurally debilitating, expose the reinforcement in low-volume reinforced concrete roads to deleterious substances, which may reduce its effectiveness leading ultimately to structural failure. In un-reinforced low-volume concrete road these cracks appear unsightly and cause the road user an unpleasant riding experience. Many researchers believe that plastic shrinkage crack development remains a concern to the concrete industry, occurring in particularly large–area pours such as low-volume concrete roads, and therefore requires further research to understand their formation and minimization. This study reports findings on the effectiveness of oxyfluorinated polypropylene fibres to control plastic shrinkage cracks, and the effect the addition of ultra-fine material has on the formation and/or propagation of these cracks. Findings indicate that low volume dosages (2 kg/m³), of oxyfluorinated polypropylene fibre significantly reduced the formation of plastic shrinkage cracks under test conditions. Furthermore, that the addition of ultra-fine material in excess of 63 kg/m³ increased the formation and/or development of plastic shrinkage cracks.

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