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Wildfires are a perennial problem in the Northwest of USA. Wallowa Whitman National Forest fires are quite frequent as a result forest completes between 10,000 and 15,000 acres of burning in a year. According to research, it was reported... more
Wildfires are a perennial problem in the Northwest of USA. Wallowa Whitman National Forest fires are quite frequent as a result forest completes between 10,000 and 15,000 acres of burning in a year. According to research, it was reported that the study area experienced fires from 1970 to 2006 with total burning of 149 fires and total burnt area of 7,583 hectares per year which observed to be between June and October. In Wallowa County, over 80% of fire starts are caused from lightning and 20% are attributed to human-caused fire starts. A GIS proved to be used effectively to map forest fire risk zone with the aid of LANDSAT satellite images and high resolution Google Earth images. FARSITE was used to predict fire intensities across a landscape. Results indicated that using GIS and FARSITE, one can generate a reliable management strategy, hence, minimising both life and property loss.
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The amount of glass waste generated by glass manufacturing and recycling companies creates serious environmental challenges. The utilization of glass waste in concrete to mitigate such challenges involved the adaptation of the material... more
The amount of glass waste generated by glass manufacturing and recycling companies creates serious environmental challenges. The utilization of glass waste in concrete to mitigate such challenges involved the adaptation of the material with respect to the fundamental requirements. This research involved the beneficial use of two types of soda-lime glass wastes in concrete, as partial replacement of cement and fine aggregate, in order to enhance the greening of the environment. The glass wastes were produced in large quantities by glass recycling companies in Gauteng, South Africa. Low alkali cement, CEM V/A 32.5N, a composite cement with 25% Fly Ash (FA) and 18% Ground Granulated Blast-furnace Slag (GGBS) was used. The two types of glass waste, namely, Superfine Waste Glass Sand (SGW), a fine residue of glass recycling processes and Ceramic Stone and Porcelain (CSP) glass waste, cullet contaminated with ceramics, stones and porcelain; were respectively used as sand and cement replacements. As collected, SGW was sieved and blended with fine sand in line with the recommendations of the South African National Standard (SANS) for sieve analysis. CSP was sorted from contaminations, through decantation, dried in the oven at 104 oC for 24 hours, grounded into powder with rod and ball mills successively; and sieved through 75µm mesh. The tests conducted include sieve analysis, particle relative densities, compacted bulk densities and loose bulk densities; in accordance with the Cement and Concrete Institute (CC the second set consisted of 10%, 20% and 30% of glass powder (GLP) replacement of cement; the third set consisted of 10% GLP in combination with 20%, 40%, 50% and 60% of SGW, respectively; the fourth set consisted of 20% GLP in combination with 20%, 40%, 50% and 60% of SGW, respectively; and the fifth set consisted of 30% GLP in combination with 20%, 40%, 50% and 60% of SGW, respectively. Subsequently, cube specimens were tested at 3, 7 and 28 days for compressive strength, according to the SANS recommendations. It was found that, the glass waste were effectively adapted in concrete. SGW was adequate for blending with fine aggregates as it improved the gradation of the blend. SGW and GLP increased the workability of the fresh concretes and significantly reduced the weight of the hardened concrete by 6.5%. Glass powder reacted as early reactive pozzolanic material, as it enhanced the 3 days compressive strength of the concrete by 14% when compared to the control mix with natural aggregates. Compressive strengths obtained from the laboratory tests ranged between 18.8 MPa and 32.7 MPa, which were 65% above that of the control mix. Up to 30% of glass wastes used as cement and fine aggregate replacement, respectively, did not impair the 28-day compressive strength of the concrete. The blend with 20% GLP and 40% SGW exhibited the same 28-day compressive strength as that of the control mix value with a value of 25.86 MPa. The mix with 20% GLP and 20% SWGS exhibited the highest strength at 28 days with a value of 32.7 MPa which represented an increase of 26.5% of the compressive strength of the control mix. The research demonstrated the beneficial use of glass waste as partial replacement for cement and sand in concrete. This will appreciably reduce the amount of glass waste dumped to the landfill sites and enhance the greening of the environment, with the added advantage of preservation of virgin materials for posterity.
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This research investigated the effects of future climate change on pavement life in South Africa by simulating prolonged moisture presence in the pavement subgrade. The study was conducted on roads P435 and P443 within uMkhanyakude... more
This research investigated the effects of future climate change on pavement life in South Africa by simulating prolonged moisture presence in the pavement subgrade. The study was conducted on roads P435 and P443 within uMkhanyakude District Municipality. Climatic data were collected from the Council for Scientific and Industrial Research (CSIR) and Climate Systems Analysis Group (CSAG) from 1940 to 2001 and simulated from 2012 to 2062. Sampling was done using the standard procedure described in Technical Methods for Highways (TMH) 5 and soil laboratory tests carried out according to TMH 1. Results of laboratory tests classified the materials as G10 based on their California bearing ratio (CBR) and plasticity index (PI). Relative compaction of 91.4 and 94.3% were obtained from the CBR test on the subgrade layers of roads P435 and P443 respectively. The research showed that 50 years into the future will bring a climate change signal that will be minimal in terms of precipitation. However, natural weather variability threatens to be the dominant signal. The pavement life has been shown to decrease in a way that would threaten the road category and design reliability.
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Constructed wetland is an innovative and emerging ecological technology for wastewater treatment. This study was conducted to investigate the effectiveness of a Vegetated Submerged Bed Constructed Wetland (VSBCW) for removal of heavy... more
Constructed wetland is an innovative and emerging ecological technology for wastewater treatment. This study was conducted to investigate the effectiveness of a Vegetated Submerged Bed Constructed Wetland (VSBCW) for removal of heavy metals from industrial wastewater in a steel manufacturing company. A pilot Effluent Treatment Plant (ETP) consisting of equalization basin, two VSBCW basins and a storage tank was constructed. The VSBCW was constructed using 10-30 mm round granite for the different zones. This was overlaid by 200 mm deep granite and 150 mm washed sand with Phragmites karka, Vetiveria nigritana and Cana lilies as macrophytes. Irrigation of macrophytes using effluent from the industry was done after 3 months of planting and ETP monitored. Industrial wastewater samples were collected and analyzed for heavy metals such as zinc (Zn), lead (Pb), iron (Fe), manganese (Mn), magnesium (Mg) and chromium (Cr) to know the treatment efficiency of the ETP. Results indicated that the removal efficiencies of the VSBCW for Pb, Mg and Cr were 15.4%, 79.7% and 97.9% respectively. Fe and Mn were seen to increase by 1.8% and 33% respectively. The ETP using locally available macrophytes is effective in the phytoremediation of heavy metals, particularly Cr from the wastewater.
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Factors influencing pavement designs are divided into two, namely controllable and non-controllable. Controllable factors include engineering design, selection of materials, construction quality and control, standards and progress.... more
Factors influencing pavement designs are divided into two, namely controllable and non-controllable. Controllable factors include engineering design, selection of materials, construction quality and control, standards and progress. Uncontrollable factors include climate, terrain and geological conditions such as surface and sub-surface hydrology. Therefore there are many influential factors that the engineer cannot control and hence understanding risk and reliability is a key aspect of design to cater for uncertainties. It is believed that by the year 2100, world climate will have changed in ways that are difficult to imagine - as difficult as it would have been at the end of the 19th century to imagine the changes of the 100 years since. The current heat, drought, floods and rainfall spurts are evident of the effects of climate change. The response to climate change is often seen as twofold; adaptation and disregard. Adaptation often viewed as the most essential part of the response to the threat of climate change whereas disregard comes from a poor understanding of the influential factors of the African climate. Severe lack of local weather data, particularly for central Africa is also part of the problem. This lack of knowledge makes it very difficult to predict with any degree of accuracy what will happen as a result of climate change at a country, or even sub-regional level in Africa. Extensive research has been done by climatologists on the subject of climate change. However, engineers and technologists have not yet adapted an approach that aims to address the topic within the engineering sector. Improvements ought to be made particularly on climate based parameters used in transportation engineering and designs. The Macro Climatic Regional Map of Southern Africa adopted from Weinert (1980) by Technical Recommendations for Highways (TRH4) (1994) is one of the most outdated weather based catalogues used in the industry. To date, even in light of the eminent threat of climate change, no credible advances have been made yet for any improvements on this over thirty year old design climatic regional map. Minor editions on the Weinert N-Values include up to ten percent adjustments on net cold binder whereby an increase is made on dry areas (N-value > 5) and reduction in wet/humid areas (N-value
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Abstract The increasing population have resulted in a higher generation of domestic and industrial wastewater sludge. The sludge ends up as a landfill in designated areas which makes the land unusable. The search for lightweight materials... more
Abstract The increasing population have resulted in a higher generation of domestic and industrial wastewater sludge. The sludge ends up as a landfill in designated areas which makes the land unusable. The search for lightweight materials for construction has led to the use of sludge as a viable replacement for the basic composition of concrete due to its low density. The dry sludge collected from Polokwane Waste Water Treatment Works (WWTW) in Limpopo Province was used as a partial replacement of sand in concrete. The sludge content in the sand was varied from 2.5, 5, 7.5, 10, to 12.5 %. The outcomes of the analysis indicate that the partial replacement of sand with dry sludge in the concrete mix is viable and useful. The result showed that up to 7.5 % of sand could be replaced with dry sludge in concrete for structural applications. Also, wastewater can be used as a curing medium. The unit weight of the concrete decreased with increasing sludge content, which was attributed to the lower density of the sludge. The SEM image revealed a porous nature and irregular surface morphology of the sludge and the concrete.
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Most construction projects take place on soil and fewer projects are carried out on solid bedrock. Therefore the bearing capacity of any soil must be evaluated prior to the construction of any road. The bearing capacity or strength of... more
Most construction projects take place on soil and fewer projects are carried out on solid bedrock. Therefore the bearing capacity of any soil must be evaluated prior to the construction of any road. The bearing capacity or strength of granular materials for road construction is measured in terms of California Bearing Ratio (CBR). This test method has been used for the past seven decades with very limited improvements in its lifetime especially with regards to the time it takes to complete. It is considered one of the most fundamental tests of any granular material in road construction. It takes any soil laboratory a period of at least seven days to produce a comprehensive set of CBR and Indicator tests. The former is in essence a five day long test method. The waiting period means whatever progress that can be made with regards to construction on site will in the meantime be all based only on experience of site technical staff and very little scientific reliance. Therefore there is a need to make improvements on current test methods in order to expedite such a lengthy test procedure. The methodology followed in this research included extensive soil laboratory testing, particularly CBR tests on identical samples that are compacted at Optimum Moisture Content (OMC) and compressed after soaking at varying daily intervals. The results of such tests for all the specimen are then plotted on a graph to obtain a trend that will best represent the plotted data such that a formula can also be developed. An equation aimed at obtaining CBR strength of materials within a shorter timeframe than the current five day period it takes to soak and compress the soil specimen has been derived from the obtained data. Preliminary findings reveal that the equation is ideal for use on weaker gravels used as subgrade for road pavements as it has only been tested on such materials. These are materials that generally have a CBR strength ranging from 3% to 15%. Thus far, the formula has provided an impeccable correlation with the conventional four day CBR strength test method. The equation, similarly to other test methods such as DCP, provides a rapid and accurate way to determine the CBR of weaker materials. Ordinarily, the Maximum Dry Density (MDD) and CBR test alone would take five days to complete and the proposed formula shall drastically reduce that turnaround time as it manages to remove the entire four day soaking period. This means the CBR of such materials can be confirmed in two days, the same day as the actual MDD.
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Disasters related to climate change on our water resources are on the rise in terms of scale and severity. Therefore, predicting groundwater levels (GWL) is a crucial means to aid adaptive capacity towards disasters related to climate... more
Disasters related to climate change on our water resources are on the rise in terms of scale and severity. Therefore, predicting groundwater levels (GWL) is a crucial means to aid adaptive capacity towards disasters related to climate change in our water resources. In this study Gradient Boosting (GB) regression modelling approach for GWL prediction as a function of rainfall and antecedent GWL is used. Firstly, we sought to demonstrate the effects of rainfall changes on our groundwater resources through a Mann-Kendall trend analysis. Secondly, we evaluated the relationship between the input and response variables and determined the optimal lag times between the variables using autocorrelations and cross-correlations. Lastly a predictive model was developed for eight groundwater stations in the Upper Crocodile. 50 % of the groundwater stations revealed declining trends, while 25% had no trends and the other 25% showed an increasing trend. Generally low cross-correlation maximum (CCma...
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The microstructures and properties of ternary copper-niobium-graphite (Cu-Nb(nano)10-C4, and Cu-Nb(micron)10-C4) composites produced via spark plasma sintering (SPS) technique have been investigated for their potential use as electrical... more
The microstructures and properties of ternary copper-niobium-graphite (Cu-Nb(nano)10-C4, and Cu-Nb(micron)10-C4) composites produced via spark plasma sintering (SPS) technique have been investigated for their potential use as electrical connection materials at high-temperature application. Nowadays, there is much activity in the development of such material all over the world. This study was aimed to compare the effect of adding the nano and micron particles sizes of Nb powders in the microstructures and properties of Cu-Nb-C composites sintered at 700 and 650 °C temperatures. The investigated materials have been produced via the SPS method. The microstructures were observed by electron microscopy technique, the wear test was observed by Anton-Paar TRB3 tribometer, thermal diffusivity was observed by LFA427 NETzschlaser flash device within the temperature of 100–900 °C, and the corrosion test was performed by potentiodynamic polarization. The discoveries have been presented in the m...
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Abstract Stormwater affects the economic situation of the environment, changes the land use, which also affects the ecosystem. Consequently, this affects the pavement condition of the road and lead to both structural and functional... more
Abstract Stormwater affects the economic situation of the environment, changes the land use, which also affects the ecosystem. Consequently, this affects the pavement condition of the road and lead to both structural and functional pavement defects. In a bid to proffer solution to the harmful effects of stormwater and reduce the cost of pavement construction in track with sustainability, this research utilized nano clay in the development of permeable concrete. The nano clay was used as a partial replacement for cement. It was dehydroxylated at 720°C; the characterization and particle geometry was done using the XRF equipment. The de-hydroxylated nano clay was used as a partial replacement for cement at 5, 10, 15, 20 and 25%. Correspondingly, six samples of concrete were developed. The mechanical properties (compressive and flexural strength) of the permeable concrete was assessed at 3, 7, 14, 21 and 28 days. Additionally, the porosity of the concrete was determined using Archimedes principle. The result of the research showed that using nano clay replacement at 15% gave a flexural strength of 4.01MPa. This is lower than the required specification of 4.27Mpa—4.5MPa for pavement construction at 28 days and 4.5Mpa and above for airfield pavement. The porosity test using Archimedes principle showed a satisfactory result. This proves the efficiency of the concrete for stormwater control. Therefore, this concrete is recommended for use in the design and construction of low axle or low trafficked road for stormwater control and aquifer recharge based on the flexural strength.
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This study examines the effect of elevated temperature on the strength of concrete containing glass powder (GWP) as Ordinary Portland cement replacement. The cement was partially replaced by 0, 15, 18, 21, 24, 27 and 30 % of GWP and... more
This study examines the effect of elevated temperature on the strength of concrete containing glass powder (GWP) as Ordinary Portland cement replacement. The cement was partially replaced by 0, 15, 18, 21, 24, 27 and 30 % of GWP and samples were prepared at constant water-binder ratio of 0.5. The cube samples after curing in water for 90 days were exposed to 60, 150, 300 and 500°C temperatures increased at a heating rate of 10°C/min. Compressive strength values were measured on unheated samples and after air-cooling period of the heated samples. Scanning electron microscope (SEM) was carried out on selected samples to examine alterations in the matrix and interface. The results indicate a decrease in the compressive strength with increasing temperature, and significant alteration was observed in the concrete matrix and interface from the SEM analyses. However, the results indicate that concrete samples containing 21% GWP exhibit higher strength compared to control.
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The objective of the study was to evaluate the phytoremediation potential of the aquatic macrophyte Typha latifolia for removal of cadmium, chromium and lead from synthetic wastewaters in constructed wetlands (CW). Four laboratory scale... more
The objective of the study was to evaluate the phytoremediation potential of the aquatic macrophyte Typha latifolia for removal of cadmium, chromium and lead from synthetic wastewaters in constructed wetlands (CW). Four laboratory scale CW units were set up, each containing granite and soil. Typha latifolia was planted in the 1st unit then intercropped with Vetiveria zizanioides, Phragmites australis and Cyperus latifolius in the 2nd, 3rd and 4th unit respectively. The units were treated to wastewaters of different metal concentrations and metal combinations. Wastewater was sampled at different retention periods. Results showed substantial reduction in metal concentrations. Metals were removed in the order Cr>Cd>Pb with maximum removal efficiencies being 96.36±0.52%, 95.70±1.26% and 80.59±3.58% for Cd, Cr and Pb respectively in the typha only units. The percentage removal of the metals increased with increase in retention time. This study recommends application of Typha latifo...
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South Africa has experienced land development growth in many areas resulting in large increases in traffic volumes. The increase in traffic volumes encouraged changes of travelling patterns and congestion on the road network. This study... more
South Africa has experienced land development growth in many areas resulting in large increases in traffic volumes. The increase in traffic volumes encouraged changes of travelling patterns and congestion on the road network. This study aimed to investigate the impact of land-use change on existing intersection peak hour factor (PHF) where access to a land development is gained from one intersection approach in the vicinity. To achieve this, intersections with traffic counts conducted before and after land-use change in the vicinity were investigated. Intersections which are major access points to a land-use were selected. Three intersections within the boundaries of the City of Tshwane with the required criteria were found. Analysis was conducted at the affected intersection approaches where land-use change took place. An increase of up to 50 per cent in traffic volumes was experienced at the intersection approaches due to change in land-use. However, the increase in traffic volume...
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This article looks at developing a decision-support matrix to optimise the selection of on-site sanitation systems for informal settlements, using the City of Johannesburg as a case study.
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This study investigates the effect of using ethanol as the process control agent during the wet ball milling of niobium (Nb). Dried nanocrystal Nb powders, of high purity, with particle sizes, ranging from 8.5 to 14.3 nm, were synthesized... more
This study investigates the effect of using ethanol as the process control agent during the wet ball milling of niobium (Nb). Dried nanocrystal Nb powders, of high purity, with particle sizes, ranging from 8.5 to 14.3 nm, were synthesized by ball milling. Commercial Nb powder of particle sizes of − 44 µm was employed by using the planetary ball mill equipped with stainless still vials with still balls in ethanol. A ball-to-powder mass ratio of 10:1 was used at a rotation speed of 400 rpm, an interval of 15 min with an interval break of 5 s, and a milling time of 10 h. The powder was dried in vacutec at a temperature of 100 °C, using a speed of 15 rpm in the vacuum of 250 mbar at a time of approximately 653 min. The crystal phase of the dried powders was analyzed using X-ray diffraction (XRD) with CuKɑ radiation, and by modification of the Scherrer equation, a single crystallite size of 11.85 nm was obtained. The morphology of the particles was observed using scanning electron micros...
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Wastewater dry sludge has to be stabilized when used in the concrete paving bricks to reduce biological activity, prevent the release of toxic metals into the environment, and reduce odor during production. The purpose of this study is to... more
Wastewater dry sludge has to be stabilized when used in the concrete paving bricks to reduce biological activity, prevent the release of toxic metals into the environment, and reduce odor during production. The purpose of this study is to investigate the soluble elements leachable from concrete pavement brick using wastewater dry sludge.The ability to measure the organic composition of wastewater dry sludge is essential, aiming at evaluating the difference in organic composition from various wastewater treatment plants in Limpopo Province. The initial phase of the investigation is to identify the existence of microbiological elements by measuring the colony-forming units using serial dilution plating on nutrition medium forms. The second part involves evaluating the differences in organic composition in various sludges using a scanning electron microscope and energy dispersive X-ray, as well as testing for soluble metal leaching by immersing concrete paving brick samples in iodine water for 28, 90, and 140 days.
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Abstract Major challenges facing groundwater management arise mostly from approaches aiming at ensuring water resources sustainability, water quality protection and aquifer restoration. In many old polluted sites, the most challenging... more
Abstract Major challenges facing groundwater management arise mostly from approaches aiming at ensuring water resources sustainability, water quality protection and aquifer restoration. In many old polluted sites, the most challenging practice is the management of decanting contaminated water from flooded shaft that decants into the natural environment. Pump and treat (PAT) is one of the commonly used techniques in management of groundwater pollution problem. Simulation-Optimization (S-O) models have proven to be very useful in appropriate design of an effective PAT groundwater remediation system. In this study, simulation models MODFLOW and MT3DMS for groundwater flow and transport respectively, and a solving constraint integer program (SCIP) optimization algorithm were employed in designing of an effective system for cleaning and controlling pollution coming from hypothetical decanting site. Simulation models were used to predict the spatial and temporal variation of contaminant plumes and aquifer response to remediation measures. SCIP optimization algorithm, on the other hand, was applied to determine the optimal solution of the formulated objective function while attaining a set of water quality and head constraints as well as operation bounds. Results from this study indicated that the optimal pumping rates for the proposed pumping wells met water quality and water head requirements. Further, the obtained results demonstrate the application of SCIP in conjunction with simulation models as a capable tool in designing an effective groundwater management system and control decanting problem. The performance of SCIP is also compared with genetic algorithm (GA) and the SCIP is found to have a better convergence rate than the GA.
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Background: Corrosion of reinforcement impedes the structural integrity of concrete infrastructures by reducing the flexural, shear and axial strength of concrete, thereby making it structurally weak. Aim: This research assessed the... more
Background: Corrosion of reinforcement impedes the structural integrity of concrete infrastructures by reducing the flexural, shear and axial strength of concrete, thereby making it structurally weak. Aim: This research assessed the corrosion effect of rice husk as a concrete constituent for the design of long-lasting concrete infrastructures. Materials and Methods: To achieve the aim of this research, rice husk was air-dried for two days and then burnt at a temperature of 600oC. It was used as a partial replacement for cement at 0%, 10%, 20% and 30% replacement of cement. The concrete pore solution was extracted by mechanical means. This was used as the medium to assess the weight loss and calculate the corrosion rate at seventy-two (72) hours interval with a focus on the temperature of the environment. The corrosion inhibition of the steel rebar was determined using the weight loss method. Results: The result was analysed and modelled using a response surface analysis. The optimis...
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Groundwater constitutes an essential resource that augments surface water resources in meeting the water supply needs of man and the ecosystem. Most importantly in arid and semi-arid environments where rainfall patterns are erratic,... more
Groundwater constitutes an essential resource that augments surface water resources in meeting the water supply needs of man and the ecosystem. Most importantly in arid and semi-arid environments where rainfall patterns are erratic, groundwater resources are often the preferred source of water. This causes enormous pressure on the resource leading to diminishing groundwater resources. Land use changes also impact on groundwater resources through alterations in the hydrologic regime. It is imperative therefore to evaluate groundwater recharge dynamics under changing land uses to provide for a better resource planning and allocation. We present in this study, an investigation into groundwater recharge dynamics of the Olifants Basin, a water stressed basin in Southern Africa over the past decade with considerations to land use changes. Three land use change scenarios were developed to simulate the groundwater recharge of the basin within the Soil and Water Assessment Tool (SWAT) environment. The SWAT model was calibrated (1988–2001) and validated (2002–2013) with good model performance statistics; NSE, R2, PBIAS, RSR of 0.88, 0.89, −11.49%, 0.34 and 0.67, 0.78, −20.69%, 0.57 respectively for calibration and validation stages. Findings indicate groundwater recharge declined by 10.37 mm (30.3%) and 2.34 mm (9.82%) during the periods 2000–2007 and 2007–2013 respectively. The decline in groundwater recharge was linked to the changes in urban (9.2%), agriculture (6.1%), rangelands (−16.8%) during the period 2000–2007 and urban (1.3%), agricultural (14%), rangelands (−14.8%) during 2007–2013. The SWAT model reveals it capabilities as a decision support tool (DST) in groundwater recharge assessment for large scale basins.
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Research Interests: Acacia and Carbonation
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The ZEMCH2013 International Conference is a follow-up to the 2012 conference that was held in Glasgow UK. It brought together academic and industry experts from Australia, Canada, China, Italy, Japan, United Kingdom, United States, United... more
The ZEMCH2013 International Conference is a follow-up to the 2012 conference that was held in Glasgow UK. It brought together academic and industry experts from Australia, Canada, China, Italy, Japan, United Kingdom, United States, United Arab Emirates, Spain, Philippines, Iran, Saudi Arabia, Qatar among others in interactive sessions that discussed the issues surrounding the analysis, design, production and marketing of low- to zero-energy mass customizable homes and communities from around the world. The conference was open to any stakeholders who are involved in housing research, business, teaching, and policy. The effect of climate change is widely experienced around the world to include rising sea water levels, ambient temperatures that would impact on the indoor comfort of those in buildings. Yet housing is a complex system of energy and environment that demands a delicate balance between the needs and wants of the society. Housing is a major building block of the urban core o...
Black cotton soil (BCS) is a class of expansive soil which is unsuitable as pavement material due to its swelling and shrinkage characteristics. The sample site location is on the north west of South Africa. The approach that is adopted... more
Black cotton soil (BCS) is a class of expansive soil which is unsuitable as pavement material due to its swelling and shrinkage characteristics. The sample site location is on the north west of South Africa. The approach that is adopted when such material are encountered is to remove the soil and replaced with quality materials. Cost of replacement is very high and stabilization of the soil is another alternative method of construction. Ground granulated blast furnace slag (GGBFS) is a by-product in the manufacturing of steel while fly ash (FA), a residue generated in combustion of coal is industrial waste that is readily available in the country. To sustain the environment by reducing the material to land fill sites, this paper examines the effect of FA and GGBFS respectively on consistency limits of BCS. Consistency limit is an indicator of clay behaviour and its evaluation provides basic mechanical data about the soil. Samples of the soil were obtained at a depth of 0.5m below th...
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Utilisation of industrial waste products with black cotton soil (BCS) in the improvement of its engineering properties has gained attention to the sustainability of the natural resources and cost efficiency. This paper evaluates the... more
Utilisation of industrial waste products with black cotton soil (BCS) in the improvement of its engineering properties has gained attention to the sustainability of the natural resources and cost efficiency. This paper evaluates the influence of fly ash, ground-granulated blast furnace slag and lime at 12%, 8% and 1–9%, respectively, on BCS obtained from the N4 road North West Province, South Africa, to improve the soil. The performance of the modified BCS cured for 7, 28, 60 and 90 days was evaluated using compaction, California bearing ratio (CBR) and unconfined compressive strength (UCS) test according to standard specifications. The CBR value increases with increase in the level of compaction. The influence of the waste materials added for different compaction levels and curing periods improved the CBR and UCS values significantly. UCS of the stabilised BCS meets with the specification for sub-base material at 97% and 100% compaction for all the curing periods.
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This paper introduces the application of GIS in how to make Orienteering maps, in how to select the field of Orienteering and in how to design the route of Orienteering. It also analyzes the process of making the Orienteering map in... more
This paper introduces the application of GIS in how to make Orienteering maps, in how to select the field of Orienteering and in how to design the route of Orienteering. It also analyzes the process of making the Orienteering map in detail and points out the shortages. At last it puts forward the frame and the development project of Orienteering map assistance design system based on Geographic Information System (shortened as GIS).
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Research Interests: Engineering and Asphalt
... (1992); Gharbi and Peralta (1994); and Magnouni and Treichel (1994). Like any other resource management, groundwater manage-ment is generally carried out in an environment of uncertainties. Thus, the question of reliability of the... more
... (1992); Gharbi and Peralta (1994); and Magnouni and Treichel (1994). Like any other resource management, groundwater manage-ment is generally carried out in an environment of uncertainties. Thus, the question of reliability of the model output is of paramount importance. ...
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Abstract This study aimed at applying the Data Based Mechanistic (DBM) modelling approach to develop a simple, parsimonious and discernable Flow-Concentration (FC) model that can be partitioned into the various identifiable pathways... more
Abstract This study aimed at applying the Data Based Mechanistic (DBM) modelling approach to develop a simple, parsimonious and discernable Flow-Concentration (FC) model that can be partitioned into the various identifiable pathways associated with the ...
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ABSTRACT Techniques used to solve multi-objective optimization problems, are meant to identify the non-inferior (Pareto set) set of solutions for consideration by the decision maker. This set is usually large and identifying one policy... more
ABSTRACT Techniques used to solve multi-objective optimization problems, are meant to identify the non-inferior (Pareto set) set of solutions for consideration by the decision maker. This set is usually large and identifying one policy for implementation can be quite challenging. Traditionally, it has been assumed that once this set is identified, it should be presented to the decision maker who should then be left alone to make a choice of a policy for implementation. It is true that the decision maker may not even understand the numerical values presented to him in the name of optimal solutions, hence the choice of a single policy for implementation would be, at best, random. This, therefore, calls for decision support tools, which can help a decision maker choose one policy among others for implementation. This paper presents such a decision support tool, which is developed within the framework of utility theory. The applicability of the tool is demonstrated through an example of a groundwater aquifer whose input parameters are uncertain and is formulated within a multi-objective framework. Results show that such a tool can use supplementary information to assist a decision maker in his search for a single policy to implement, hence quantifying his choice.
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Groundwater is the most accessed freshwater source in Nigeria. However, the groundwater resource sector of Nigeria is confronted with pollution problems arising from both natural causes and human activities. The current study examines the... more
Groundwater is the most accessed freshwater source in Nigeria. However, the groundwater resource sector of Nigeria is confronted with pollution problems arising from both natural causes and human activities. The current study examines the case of a faith-based campus whose water needs are 100 % serviced via groundwater. The campus accommodates about 15,000 full time residents and about 200, 000 weekly visitors. The campus is provided with water from 30 boreholes which is pumped directly into elevated tanks. Four water samples which were obtained from four boreholes within the campus were analysed for physico-chemical contaminants using standard methods. This was done to confirm the potability of the water which is being consumed by residents. Results of the analysis of the groundwater in the study area showed that all the water samples met the minimum requirements of the National Standard for Drinking Water Quality (NSDWQ) for sulphate, nitrate, chloride and Total Dissolved Solids (TDS). However, 75 % of the water samples were slightly acidic as they fell below the NSDWQ range limit of 6.5 – 9.5. Furthermore, all the water samples exceeded the NSDWQ limit of 400 mg/L for hardness. Cadmium was also found to exceed the NSDWQ limit of 0.003 mg/L in all water samples while 50 % of the water samples slightly exceeded the 0.5 mg/L limit for Iron. The presence of cadmium in most of the water sample suggests that there is high risk in consuming water from these boreholes. Cadmium is a very toxic metal which bio-accumulates in the body. This leads to neurological problems as well as organ failure which ultimately leads to death. Similar experiments conducted by other students in the past five years suggest that the problem of cadmium is persistent. Also, results of soil tests conducted by another group of students suggest that the ambient soil may be the source of this pollutant since all four tested soil samples contained cadmium with values ranging between 28, 800 % to 1.36 million % of the limit for cadmium in water. Due to the life threatening effect of cadmium on humans, it was concluded that water from the study area should not be consumed without treatment. These experiments which were conducted by students of the university demonstrate that undergraduates can contribute to solving the myriads of water related problems in the society. BACKGROUND: Nearly 40% of Nigerian population withdraws groundwater for domestic use. The water is often consumed without any form of treatment because it is perceived to be pure. This is not often true.