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Prevalence Of Hiv/Aids In Tuberculosis Patients Living In The Lowlands Of Mafeteng District In Lesotho
Get PDFDissertationBackground: Tuberculosis (TB) is one of the oldest known diseases that kills humans, yet still remains among the top infectious disease killers worldwide today. The World Health Organization (WHO) states that up to 10 million people continue to fall ill with TB every year. Almost three-quarters of the TB infections are reported from the African region and almost a quarter of these are mentioned to be co-infected with human immunodeficiency virus (HIV) (WHO, 2018). WHO classified Lesotho as one of the countries carrying a large burden of TB/HIV co-infection in the Africa region (MOH, 2016). Therefore, this study was conducted in order to determine the prevalence of HIV among TB patients living in the lowlands of the Mafeteng district in Lesotho from 2014–2016.
Methodology: A quantitative research approach was conducted by means of a convenience purposeful method of sampling. The method followed was to collect TB/HIV data from the five participating Health Care Centres (HCCs) for the years 2014 – 2016. These data were sourced from handwritten TB registries of the five identified HCCs and the sampling size of 1,109 study participants was selected from all age groups located in the lowlands of the Mafeteng district in Lesotho.
Results: Out of the 1,109 TB patients studied, 780 (70.3%) were also co-infected with HIV. Among the HIV patients, the most prevalent site of TB infection was pulmonary including a total of 665 patients (85.3%), while 115 (14.7%) had extra-pulmonary TB (ET-TB). The number of new TB patients with HIV was 638 (81.2%) and retreated patients numbered 142 (18.2%). A total of 457 (41.2%) fell in the mean age group of 15 to 35 years. 99% of these co-infected patients were receiving anti-retroviral therapy (ART). Most of these HIV/AIDS patients were from the Mafeteng HCC with 501 (64.2%) of the 1,109 patients. The most affected age group among the patients were the young adult age group (>15 to 35 years) and the adult age group (>35 to 55 years) with 45.8% and 40.6% of the total 780 HIV/AIDS patients, respectively. The distribution of male HIV/AIDS patients among the participating HCCs was 470 (60.3%), while the distribution of female HIV/AIDS patients among the participating HCCs was 310 (39.7%) of the total 780 HIV/AIDS co-infected patients. Most of these HIV/AIDS patients were reported from the Mafeteng main HCC.
Discussion: In this study, TB notification cases declined substantially when comparing reporting Year 1 and 2 with reporting Year 3. It was also interesting to take note that the number of HIV/AIDS cases in the most affected young adult age group interval (>15 to 35) dropped in reporting Year 3. Ultimately, the number of HIV/AIDS cases in the age group interval of adults (>35 to 55) was more in reporting Year 3 compared with the number of cases in the young adult group in the same reporting year.
Conclusion: The findings of the study concluded that there is a high prevalence of HIV/AIDS among TB patients living in the lowlands of the Mafeteng district in Lesotho. Therefore, National and district level administrative bodies and health care centres should collaborate to strengthen the efforts and place TB and HIV/AIDS services among their priority interventions. These include identifying the possible routes of TB transmission because of limited infection control measures, drug resistance, poor TB prognosis and adherence to treatment. Future researchers could consider assessing the main reasons behind the high prevalence of HIV/AIDS among male TB patients in the Mafeteng district of Lesotho
Chest Radiography: Optimising The Dose At Industrial Mines In The Northern Cape
Get PDFOccupational medical testing requires an employee to perform certain medical tests before he/she can be classified as fit for duty. A chest x-ray is part of such medical tests. Contracted employees are employed over different periods of time to complete a contract on a mine. When they enter and leave the site, a medical examination is required, which includes a chest x-ray (CXR).
The aim of the study was to establish whether certain contracted employees receive more than one CXR per annum, and to determine a baseline for dose reference level (DRL) for a posterior-anterior (PA) CXR for the four clinics that participated in the study and ensures the researcher and the study collaborates with radiation protection. The research questions that were addressed were: (1) are contracted employees referred for more chest imaging than permanent employees, and (2) are contracted employees receiving a higher than necessary radiation dose compared to permanent employees, due to unnecessary repetition of chest imaging at the different clinics contracted by mining companies.
A (1) technical parameters sheet, a (2) checklist of x-rays and a (3) formulae and calculations sheet were compiled in order to approach the research questions. (1) was the part of data collection the radiographer had to complete, with the permission of the employee, due to the fact that they interact with the employees when medical testing is done. (2) was done by the researcher where a search was done for previous CXRs, other x-rays and rejects/repeats. (3) was done by the researcher with the assistance of a medical physicist to calculate the Entrance Surface Dose (ESD) of each employee and ultimately determine DRL for that clinic. A univariate procedure was used to test for normality for the ESD by utilising the Schapiro-Wilk test, and presented with a statistic of 0.907037, all four clinics combined.
Firstly, the researcher conducted a pilot study to determine the research instruments’ credibility, and they proved to be user friendly. The large scale study started after all required permissions were granted and the technical parameter information were recorded by the radiographer on duty. The study found that the median patient thickness was between 21 to 25 cm. With this information the (1) ESD and DRL were calculated. The results of the checklist showed that there were no employees who had x-ray examinations at the other three clinics. (2) Clinic 1, 2 and 4 reported contracted employees only had one chest x-ray done per annum, whilst clinic 3 had 5 contracted employees who had more than one chest x-ray done per annum. The total of all four clinics combined that had only one chest x-ray done per annum were 54.25 % (217 employees) of the study population (n = 400), 2 chest x-rays = 22.50 % (89 employees), 3 chest x-rays = 8.50 % (34 employees), 4 chest x-rays = 3.50 % (14 employees), 5 chest x-rays = 3.25 % (13 employees), 6 chest x-rays = 3.25 % (13 employees), 7 chest x-rays = 3.50 % (14 employees), 8 chest x-rays = 1.25 % (5 employees) and 10 chest x-rays = 0.25 % (1 employee). There was no specific employee identified who had x-rays at another participating clinic in one year, but it was evident that certain employees received multiple x-ray examinations.
Other projections of all four clinics combined were reported as employees that had one other anatomical projection AP/PA = 2.75 %, 2 other projections AP/PA = 0.50 %, and 1 other projections AP/PA = 0.25 %. One other projection lateral = 2 %, 2 other projections lateral = 0.50 %, and 3 other projections lateral = 0.25 %. One other projection oblique = 0.50 %, and 2 other projections oblique = 0.25 %. Rejects/repeats for PA CXR for all four clinics combined reported as 1 repeat = 4.25 %, 2 PA CXR repeats = 0.25 %, and 3 PA CXR repeats = 0.50 %. There were no CXR lateral repeats. Other repeats of all four clinics combined for AP/PA were reported as 1 other repeat AP/PA = 0.50 %. Other repeats lateral was reported as 1 other repeat lateral = 0.50 %, and 2 other repeats as 0.25 %. Repeats for other projections oblique were 0.
Potential diagnostic reference levels (DRLs) for PA CXR established through research studies for an adult chest examination in four countries are included in this study, and the values were as follows: a study done in South Africa established a DRL: 0.10; Ireland a DRL: 0.16; Iran a DRL: 0.26; and Slovenia a DRL: 0.16. (3) The DRLs of this study of the four clinics were calculated and reported as Clinic 1: 0.204, Clinic 2: 0.292, Clinic 3: 0.391 and Clinic 4: 0.144.
The study results can be utilised to assist radiographers with a baseline DRL for chest imaging to optimise dose, and to assist the mines to focus on limiting unnecessary exposure to ionizing radiation by enforcing only one chest image per annum. It was evident that a DRL value assisted the radiographer to limit exposure and if mining clinics share the images, less annual imaging is needed per employee
Creating Decentralised SMART Manufacturing Units with a Newly Implemented Standard Communication Protocol
Get PDFDissertationCommunication protocols drive the flow of information from machine to machine. However, with the
requirements of the Fourth Industrial Revolution and machines set to become more mobile, flexible
and intelligent, greater communication practices are required to fully incorporate this revolution.
Machines are required less to be able to communicate in fixed networks with numerical representation,
but rather to have the ability to communicate with machines swopping in and out of manufacturing
lines and networks, all while adhering to real-time communication regulations. Furthermore, with
machines swapping in and out, a greater need is placed on this communication protocol to operate in
a purely decentralised manner, something not available on the market today. All these requirements
aid each other. While machines are able to become decentralised and
self-efficient, they rely on more crucial information, which is used to create intelligent decisions and
execute them with timely precision. This dissertation entails an extensive research in communication
protocols and their use in the manufacturing scene. From this, a newly developed communication
protocol is designed with a heavy focus placed on real-time execution in a decentralised manner. The
communication protocol is tested in a constructed water bottling plant to gauge its effectiveness and
performance. Finally, conclusions are drawn from these results, detailing and elaborating the use of
the communication protocol and the practices it ensues
Dental healthcare waste management practices in the Greater Tshwane Region
Get PDFThesis (Master of Health: Environmental Health)--Central University of Technology, 2021The healthcare waste management practices undertaken at dental healthcare facilities are of great importance due to the infectious and hazardous nature of the waste and associated risks on the environment and public health. In this study, the knowledge, attitudes and practices of respondents towards the practices or procedures used in managing dental healthcare risk waste in the Greater Tshwane region, were explored.
Data were collected from 52 respondents using a questionnaire, which probed their knowledge, attitudes and practices towards healthcare waste management (HCWM) at dental healthcare facilities. Dental healthcare staff and facility managers of a dental academic hospital, two public hospitals, one public clinic and several private dental healthcare facilities were approached to complete the questionnaire. Their responses were captured and statistically analysed through the QuestionPro® online survey software.
The results were positively indicative that dental healthcare staff consider they have sufficient knowledge of HCWM. In this study, the respondents obtained an aggregated mean average score of 83% for knowledge, 75% for attitudes and 54% for practices towards managing dental healthcare risk waste at their respective facilities. With a score of 75%, the healthcare professionals displayed good attitudes towards HCWM and the need thereof. Attitude has a direct impact on the dental healthcare waste management practices applied. Practices at 54% were a clear indicator of what is happening at the dental healthcare facilities. It was interesting to note that public dental healthcare facilities were more compliant with HCWM than the private dental facilities. Results also indicated that there was no association between practices and the age or gender of the respondents, but rather that education and training were the determining factors for the appropriate execution of HCWM protocols. However,healthcare waste management practices are influenced by and affect staff, patients, community and environment in a long run.
Among other findings, the study found that 65% of the respondents had received training on the different aspects of HCWM either as undergraduate students or at the beginning of their new employment, which leaves the question of what happened to the remaining 35%. At least 80% of the respondents agreed that they should be vaccinated against hepatitis B and that such vaccination should be paid for by the employer. Again, the question is, what happens to those where the employer is not paying for the vaccination?
The replies from participants on the in-house training they received from their employer may be subjective according to his or his or her own understanding or perspective. The need to routinely educate all categories of dental healthcare staff members in order to ensure that the appropriate and standard execution of healthcare waste management practices is effected, is of greater importance than what the participants perceived. This will further increase compliance with healthcare waste management practice protocols. The results of this study provide a baseline of the knowledge, attitudes and practices of dental healthcare staff with regard to HCWM of dental waste. It is suggested that this baseline be used by dental healthcare facilities to develop an improvement plan to address the gaps identified
Real-time monitoring and control of an aquaponic system to ensure sustainability
Get PDFThesis (Master of Engineering: Engineering: Electrical)--Central University of Technology, 2021In recent years, climate change awareness, with resultant potential dwindling water resources and strain on existing food production infrastructure, has grown. Establishing a sound scientific basis for the creation, operation, and maintenance of alternative sustainable food production methodologies is thus essential. The ‘closed system’ nature of aquaponics promises high yield versus surface area as compared to traditional agriculture and is inherently sustainable.
Since aquaponics systems may be set up in cities and suburbs, there is potential to establish food ‘cells’ that benefit the population in the immediate area. Such benefits include fresh produce, reduced storage, pollution and transportation costs, and increased employment and food security. In a climate that features freezing winter temperatures (such as in Bloemfontein, South Africa), sustainable thermal supplementation is required to maintain the viability of aquaponics systems. Monitoring and controlling thermal supplementation in real-time is necessary to mitigate thermal losses and prevent bio-filter micro-biota mortality related to extreme cold winter temperatures and to ensure sustainability.
The dynamic interrelated nature of thermal interaction between aquaponics subsystems and the large volume of water typically present in main aquaponics reservoirs further inform the necessity of implementing such a monitoring and control system. Presenting the aquaponics system and subsystems’ thermal interaction in a conceptually simplified manner, which may be applied to other aquaponics systems and topologies, also promotes integration of aquaponics into the African agricultural paradigm. The subsystem contributions, as conceptually described via water mass-flow energy transfer, may be readily quantified by differential temperature measurement and volumetric flow determination.
Furthermore, presenting a grid-equivalent energy- purchase estimation methodology to maintain sustainability potentially motivates entrepreneurs and investors by offering investment confidence, thus further incentivising adoption of aquaponics as technology. This study was conducted during an unusually severe 2020 winter season in Bloemfontein, South Africa, and fortuitous occurrence of uncommonly closely spaced cold fronts enables challenging the hypothesis expounded in the presented methodology. Offsetting midwinter temperature loss in the 42 kl main aquaponic reservoir, as further detailed in Annexure F, a 1.3°C temperature loss mitigation over a period of three days was realised. Employing the daily temperature recovery slope metric (as more examined in Annexure G), an average positive temperature recovery slope of 0.278°C was noted. The real-time nature of the online data as collected by the monitoring and control system additionally promotes adoption of such electronically enhanced aquaponics systems into the concept of ‘Sustainable Smart Cities’.
The method presented, utilising the concept of mass-flow energy transfer to quantify the subsystem energy contribution to the main aquaponics reservoir, is inherently scalable and may be readily incorporated for use in different aquaponics system topologies. As such, it represents a useful tool for further research in the field and compares favourably against the established epistemological approach of using a thermodynamic description, which is complex and computationally taxing, and can be difficult to realise for systems also containing a biological component
An Artificial Intelligence forecast system for strategic positioning in a professional competitive E-Sport
Get PDFThesis (Master: Engineering: Electrical Engineering)--Central University of TechnologyThe gaming industry is one of the largest contributors in the entertainment industry, boasting an estimated US$152.2 billion of revenue for 2018, with electronic sports (E-sports) being one of the main contributors to this astronomical revenue. One such E-sport is Counter-Strike Global Offensive (CSGO). The purpose of the study is to develop an automatic strategy predictor (ASP) for CounterStrike Global Offensive (CSGO) that will be able to determine a specific team’s strategy accurately. The ASP achieved this by developing an MVS to analyse and capture historical matches and generate a player position stencil (PPS). This PPS is then processed further to obtain the necessary information to train an artificial neural network (ANN). The development of the ASP consists of intercommunicating multifaceted software components. The first part is an image-processing section that captures the in-game mini-map within CSGO and by doing so is able to capture the player positions at a specific point in time for every playable round. This image-processing part consists of two components. The first is the player position stencil producer (PPSP); the second is the stencil processor (SP). The PPSP captures the in-game minimap using the image acquisition techniques and the SP processes the stencils captured by the PPSP and produces the player position information (PPI). An information processing system (IPS) is developed in order to process the PPI. The ISP consists of three components. The first of these was an information concatenator (IC). The IC would concatenate the PPI, captured by the SP, with the additional information obtained from the CSGO Demo Manager. The CSGO Demo Manager is a software package that produces information about every round within a match. The additional information obtained from the CSGO Demo Manager contains information such as the team’s economy, their utility, whether or not the in game device was planted or not and if the round was won or not. This is concatenated the PPI with the additional information, a comprehensive understanding of the round can be generated. Once concatenated by the IC, the information is called the overall round strategy information (ORSI). The second and third software components form part of the information pre-processor (IPp). The purpose of the first IPp software component is to retrieve the ORSI from memory and perform pre-processing on the ORSI. The purpose of the preprocessing of the ORSI is to ensure that the ORSI was in the correct format for the training of an artificial neural network (ANN). The second IPp software component separates and arranges all the information by rounds. The information of each round is separated and stored as the information file for training and is called the overall round strategy information 2 (ORSI2) file. Once each round has an ORSI2, the fourth milestone is met. Each round’s ORSI2 file is used to train an ANN. The ANN of each round is called the automatic strategy predictor (ASP). Once all the ASPs have been trained, five unseen matches are processed by the MVS, the IPS and the IPp in order to obtain five unseen ORSI2 files. These ORSI2 files are used as inputs to determine the accuracy of the ASP when predicting unseen matches. The outputs of each rounds ASP are compared to the actual player positions retrospectively. The results show that the suite of software developed in the MVS was able to capture the in-game mini-map, as well as process the PPS that was captured. The information obtained by processing the PPS was successfully processed into a format that can be used for training an ANN. The training of the ASPs was successful, as the average R values obtained for each round’s ASP, were greater than 0.98. With all the APS’s trained, five unseen matches were processed once more in order to obtain five new ORSI2s. The new ORSI2s were used to determine the accuracy of each round’s ASP when predicting the strategy used by the team within that specific round. The second round’s ASP was able to achieve an accuracy of 67%; this is expected, as there is only one prior round of information for the ASP to make an accurate prediction. The later ASPs all achieved accuracies well over 95% prediction success. The trained ASP delivered instant predictions once an input was given to the ASP and could be utilised by a professional E-sports team to study an opposing team, or by E-sports analysts and discussion panel
Comparing different scanning techniques for the design and fabrication of maxillofacial prostheses
Get PDFThesis (Master: Design)--Central University of TechnologyFacial prosthetics can play a significant role in relieving the psychological impact of patients who have lost facial features due to various causes. Traditional manual techniques of fabricating these prostheses are now largely replaced with modern computer aided design/computer aided manufacturing techniques that utilizes computerized tomography (CT) scanning for determining facial features. The prosthesis is designed from the CT data and molds produced through additive manufacturing (AM) for casting the prosthesis in silicone. Despite CT scanning presenting considerable advantages in acquiring reliable dimensional form and sizes of affected areas, it is not without complications. Key drawbacks are the high costs involved in scanning patients and the availability of these machines, which excludes many patients requiring facial prosthetics from benefitting from this technology. This study aimed to investigate if a three-dimensional (3D) handheld scanner used in healthcare and engineering industries (Artec® Spider®) can be used to generate facial digital data suitable for the fabrication of maxillofacial prostheses. A test model was designed to highlight the strong and weak points of both CT and hand-held scanners and the model was scanned with both. The 3D models generated from the hand-held and CT scanner were compared to the 3D model of the test model generated by a micro-CT scanner and compared to determine accuracy. The study showed that the hand-held scanner produced scans comparable in accuracy to CT scanner but at a much lower cost. This will enable a significant number of patients requiring maxillofacial prosthetic care to be helped
Phenotypic Characterisation Of Meatmaster Sheep Using Quantitative And Qualitative Trait Analysis
Get PDFDissertationThe aim of the study was to create a phenotypic analysis of the Meatmaster breed, utilizing linear body measurements, subjective assessments of body form, slaughter data and pedigree performance data (collected only from the ewes). The linear body measurements and pedigree performance data were collected from one hundred and eighty-seven rams (187) and two hundred and twenty-two ewes (222) of all age categories, measured both in incisor counts and number of days lived. Linear body measurements were used as the main instrument of measuring different body parts and the following means in both rams and ewes were measured: Body Weight (rams= 80.47±13.33 kg, ewes= 57.51±12.43 kg), Head Length (rams= 23.93±1.55 cm, ewes= 22.68±2.05 cm), Neck Length (rams= 28.35±5.16 cm, ewes= 29.61±3.82 cm), Chest Girth (rams= 102.45±8.42 cm, ewes= 92.95±8.08 cm) Tail Length (rams= 38.24±4.88 cm, ewes= 36.64±4.70 cm), Wither Height (rams= 63.91±4.04 cm, ewes= 58.99±4.86 cm), Chest Depth (rams= 37.51±2.97 cm, ewes= 34.47±2.97 cm), Chest Width (rams= 23.47±2.56 cm, ewes= 21.24±2.85 cm), Body Length (rams= 78.95±5.59 cm, ewes= 72.67±6.06 cm), Rump Length (rams= 21.82±3.29 cm, ewes= 20.77±1.93 cm) Rump Width (rams= 23.87±2.82 cm, ewes= 21.36±3.15 cm), Skin thickness (rams= 2.846±0.5 mm, ewes= 2.805±0.5 mm), Pelvis length (ewes= 7.66±.98 cm), Pelvis Width (ewes= 7.66±.90 cm), Pelvis Area (ewes= 46.69±10.62 cm²) and Scrotal Circumference (rams= 35.12±3.03 cm). All body measurements had a significant difference (P0.001) and tail length (P>0.001). The pedigree performance records of one hundred and seventy-seven (177) ewes showed the following means: Age at First Lambing (15.242±3.8 months), Number of Times Lambed (3.33±1.8), Number of Lambs Born (4.36±3.4), Number of Lambs Weaned (3.44±2.5) and Average Inter-lambing Period (258.64±151.3 days). Slaughtering data were compiled from two thousand two hundred and fifty one (2251) animals of different genders and ages the means are as follows: A0 (16.388±4.2 kg), A1 (16.098±3.1 kg), A2 (16.949±3.2 kg), A3 (18.138±3.5 kg), A4 (15.33±5.6 kg), A5 (14.80±0 kg), A6 (16.30±8.2 kg), Mean of A-grades (16.77±4.1 kg), AB1 (22.10±0 kg), AB2 (27.117±7.2 kg), AB3 (22.90±0 kg), Mean of AB-grades (24.039±13.8 kg), B1 (25.01±14.8 kg), B2 (26.656±5.2 kg), B3 (28.15±16.3kg), B4 (27.80±0 kg), Mean of B-grades (26.904±13.3 kg), C2 (25.127±4.3 kg), C3 (24.633±7.1 kg) and Mean of C-grades (24.88±4.9 kg). A stepwise regression was carried out using SPSS (Version 26) to determine the individual influence of body measurements on performance. An F to enter level of 0.05 was used to determine the significance of the partial contribution of each effect. Pearson correlations were conducted on the body measurements in both rams and ewes, following the guidelines of Field (2009). In order to investigate the difference between various age and area categories the Hochberg’s GT2 post hoc test was conducted. A Multiple Regression Analysis was conducted on five models using LBM as the variables. In the next step of the multiple regression analysis the tool of Model Summary boxes was used. The Durbin-Watson statistical test was used for the assumption to be made that the residuals are independent (or uncorrelated). A significant (P0.05). An interesting predictive value of R2= 0.140 was observed between the body measurement wither height and the performance trait average inter-lambing period as well as a predictive value of R2= 0.154 between the body measurement wither height and the performance trait number of lambs born. This seems to be a characteristic of the Afro-type sheep breeds which have a higher wither height and have a higher tendency to birth multiple lambs per lambing opportunity. Age has a significant influence (P<0.001) on all the body measurements of the Meatmaster, except for neck- and tail length. The environment has a significant influence (P<0.001) on all the body measurements of the Meatmaster, except for tail length
Mechanical Performance Of Warm Mix Asphalt-Treated Bases Incorporating Recycled Asphalt Pavement
Get PDFDissertationThe depletion of natural resources, the elevated cost related to the construction and the rehabilitation of pavements, the progressive change of the climate, the high heat and harmful gas emission into the atmosphere are the concerns engineers, academics, scientists and politicians have been addressing. They are co-operating toward finding efficient solutions to mitigate these global issues. Thus, the advent of Warm Mix Asphalt (WMA) incorporating Recycled Asphalt Pavement (RAP) as a long-term solution to partially or totally participating in remediating the problem of global warming, climate change and the preservation of environmental resources has gained prominent interest in certain European countries and Asia, North America and most recently in South Africa.
This thesis, therefore, aims to investigate the performances of the control Hot Mix Asphalt (HMA) technology and the WMA incorporating RAP at 15% and 30% through laboratory experiment and numerical modelling.
Consequently, the laboratory studies that involve the mix designs, the production and the testing of asphalt specimens were achieved following both the South African and the international standards. The RAP used at 15% and 30% in the WMA contains 0.8 % of 50/70 grade bitumen. The virgin aggregate called dolerite and the fillers used in the asphalt mixture were obtained at the Lafarge Olivehill Crushers site in Bloemfontein. The Sasobit, as well as the 50/70 grade bitumen binder, were collected in Sasolburg.
The numerical simulation of the WMA – 15%RAP, the WMA – 30%RAP and the control HMA was achieved through the Finite Element Method (FEM) in the Abaqus computer program and the Layered Elastic Analysis (LEA) in mePADS. The Linear Elastic Analysis (LEA) was adopted not only to validate the results found in FEM but most of all, to justify the preference of FEM over the LEA. The numerical simulation WMA – 15%RAP pavement structures, the WMA – 30%RAP pavement structures and the control HMA pavement structures was to analyse their mechanical responses under repeated loading.
The results of the laboratory experiment show that: the control HMA exhibits lower rutting performance than the WMA –15%RAP and WMA – 30%RAP;
the control HMA exhibits lower fatigue cracking performance than the WMA –15%RAP and WMA – 30%RAP;
the control HMA exhibits lower ITS (stiffness) performance when compared tothe WMA – 15%RAP the WMA – 30%RAP;
the control HMA exhibits close Marshall Stability and Flow performance tothe WMA – 15%RAP the WMA – 30%RAP.
As far as numerical modelling is concerned, the results show that the control HMA pavement structures exhibit lower rutting and fatigue cracking performance when compared to the WMA – 15%RAP pavement structures the WMA – 30%RAP pavement structures. Overall, the WMA can successfully incorporate RAP at up to 30% and can be utilized for the new construction and the rehabilitation of low to medium-traffic volume roads
Effects Of Evapotranspiration On Water Quantity And Quality Along The Modder River Catchment Using Remote Sensing
Get PDFDissertationThe effect of evapotranspiration on river catchments needs to be consistently monitored as water availability and usability affects the livelihood and health of all living organisms. The consistent monitoring of water quantity and quality at scale using ground based methods can however be costly and unsustainable. Alternative methods of monitoring such as Remote Sensing thus need to be explored and tested. The main aim of this study was to assess the seasonal water loss and variation in water quality in the Modder River due to evapotranspiration by using remote sensing techniques. Landsat 8 satellite images and data were used to compute remote sensing indices, such as the Normalised Difference Water Index and the Normalised Difference Vegetative Index, seasonally over three years (2017–2019). The remote sensing indices were used to evaluate the surface water area across the Mockes and Krugersdrift dams which are part of the Modder River catchment. The evapotranspiration values were then assessed against the surface water area. Seven water samples were taken across several points on the Modder River and the chemical and physical parameters of pH, electrical conductivity, total dissolved solids, calcium cations, magnesium cations, sodium, potassium, chlorine, nitrates, and sulphates, were used for calculating the seasonal Water Quality Index. The seasonal Water Quality Index was analysed against evapotranspiration, as well as the Normalised Difference Vegetative Index. The Pearson regression test results gave a strong r value of -0,9 between evapotranspiration and water quality relationship as well as a weak r value of -0.22 between evapotranspiration and surface water quantity, respectively. The spring and summer seasons had the maximum and minimun seasonal evapotranspiration average values of 10.1 mm and 7.8 mm respectively with corresponding poor water quality indices of 62.6 and 53.5 respectively. The average seasonal Normalised Difference Vegetative Index values for the Summer, Autumn, Winter, and Spring seasons across the 3 years were 0.34, 0,38, 0.22, and 0.26, respectively. The study outcome showed that potential evapotranspiration does have a significant effect on water quality but showed a weak correlation with surface water quantity. Furthermore, the study proved that remote sensing techniques can be used in assessing surface water quality and quantity parameters