Engineering Headway Vol. 28

Abstract: Renewable energy technologies are considered clean sources of energy and optimal use of these resources minimizes environmental impacts and is sustainable based on current and future economic and societal needs. In Namibia, wind energy can be considered one of the available renewable energy sources. Despite the abundance of wind speed distribution over Namibia, there is a lack of properly analyzed and documented data that could reveal the capabilities of wind energy generation in Namibia. This research aims to assess the wind energy generation potential for Ongwediva and with specific application to the University of Namibia Engineering Campus to determine its suitability. Data for the Jose Eduardo dos Santos (JEDS) Campus was collected from the National Aeronautics and Space Administration (NASA) Data Access Viewer. The collected data was analyzed and modelled using the Weibull probability distribution function. Results from the model predict the wind speed distribution pattern and energy density which constitute the decision variables for the suitability of wind energy application at the selected site. The yearly averaged wind speeds for the study location varied between 3.456 and 3.698 m/s while the calculated yearly averaged wind power density ranged between 22 - 27 W/m² for a single turbine. The study concluded that the appropriate wind turbine for the range of wind speed and power density for Ongwediva was the Vestas V100 which could produce 1800 kW of electrical power which may provide CO₂ savings of 4,974 tons/year. This assessment provides data for advancing wind resource development and application in the Engineering campus or around Ongwediva town.

Abstract: With avalanche of smart technological development on the horizon, one is of the view that the availability of smart technologies increases the demand for reliable, cost-effective and environmentally sustainable energy supplier system in place. To have such system in place, this study recognizes the need that necessitates a multi-disciplinary approach for the design and optimization of modern power grids. Thus, this study derives, an integrated mathematical optimization model for the development of a sustainable smart grid system that engages the interests of electrical, mechanical, metallurgical, civil, and control engineering disciplines. The engagement of such engineers has the potential to minimizes the total cost of energy generation, distribution, and infrastructure; while sustaining the environmental and maximizing energy eficiency, reliability. Therefore, to achieve our main objectives, an integrated mathematical optimization model incorporating power generation, energy demand, reliability, eficiency, maintenance costs, material lifespan, and emissions, subject to a set of constraints that ensure system balance, capacity limits, minimum reliability, eficiency, and compliance with environmental regulations. It is our strong hope that by optimizing these variables, the integrated mathematical optimization model addresses the critical challenges faced by various engineering fields. Since, electrical engineering focuses on the eficient distribution and reliability of energy; mechanical engineering on the performance and longevity of turbines and power systems; metallurgical engineering on material durability and eficiency; and civil engineering on the infrastructure required to support the grid; and furthermore, control engineering contributes automated solutions for load balancing and the integration of renewable energy sources. Thus, optimization model becomes a multi-objective optimization framework that provides a comprehensive solution.

Abstract: Road traffic crashes are a global concern, disproportionately affecting developing countries. Namibia, with a road fatality rate exceeding regional averages, faces significant economic and social losses due to FSI crashes. This study examined fatal and serious injury (FSI) crashes on Namibian’s national rural roads from 2012 to 2016 to identify trends and correlations with temporal and demographic factors. Univariate and bivariate analyses were conducted using data from the National Road Safety Council, with post-hoc tests revealing significant differences across variables. The average driver age was 28, with males at a significantly higher risk, particularly those ages 21 to 35. The temporal analysis revealed higher crash occurrences during peak traffic hours, weekends, holidays, the second week after pay week, holiday months (April-May, August and December), and the first and third quarters of the year. These findings indicate a substantial negative impact on economic development due to the high rate of serious injuries and fatalities among young and adult drivers. The study highlights the need for targeted, data-driven interventions to enhance road safety, recommending stricter traffic regulations during high-risk periods, public awareness campaigns focused on young male drivers, and improved road infrastructure in identified hotspots.

Abstract: This paper presents findings from an ongoing study on the condition assessment and numerical modelling of a reinforced concrete bridge B0140 along C46 in Ongwediva, Namibia. An analysis of bending moments, stresses and deflections of the bridge under the prevailing abnormal loads on the bridge was undertaken using Autodesk Robot Structural Analysis Professional (RSAP) software. The aim of this study was to develop a numerical model of bridge B0140. The objectives of this study were twofold, namely, to use the developed model to predict bending moments, stresses and deflection of the bridge structural elements and to evaluate the adequacy of the existing reinforcement under the prevailing environmental conditions and abnormal loads according to BS 5400 requirements. Information pertaining to the geometry of the bridge and the mechanical properties of the materials used for construction were obtained from “as-built” engineering drawings from the Roads Authority (RA) of Namibia, physical measurements and non-destructive testing in situ. Preliminary results from the developed model indicate that the bending moments, stresses and deflections of the bridge under the prevailing environmental conditions and abnormal loads are satisfactory. The developed model, however, needs further refinement, calibration and validation to improve its accuracy.

Abstract: About a third of the world's population relies on groundwater for their water supply. However, in some cases, the quality of these sources is not suitable for human consumption. Reverse osmosis (RO) membrane technology is used in many cases to improve groundwater quality. Often, for effective performance of RO membranes pre-treatment of source water is required. This study aimed to assess the performance of the pre-treatment components of the brackish water RO desalination plants at the Grünau and Bethanie water supply areas. To assess the performance of the pre-treatment components at these two water supply areas, samples for water quality analyses like turbidity, fluoride, nitrate, and hardness were collected from the raw water and pre-treated water. The average removal efficiency of Bethanie’s sand filters was -2.14% for turbidity, hardness, nitrate, and fluoride. Sand filtration is a technology employed to reduce suspended solids (i.e. turbidity) and can improve microbiological quality. Sand filtration can also be used to remove precipitates formed after an oxidant was applied for example removal of iron and manganese. The negative value indicates that the sand filters were not effective in removing these contaminants, and in fact, they increased in concentration. The raw water was classified as group C, and the pre-treated water after sand filtration was group C as well. The average removal efficiency of Grünau’s sand filters was -43.28% for turbidity, hardness, nitrate, and fluoride. Again, this negative value indicates that the sand filters were not effective in removing these contaminants, and in fact, increased the concentrations. The raw water quality was classified as group D which remained as group D after sand filtration. The raw sources of water at both the treatment plants are groundwater abstracted from boreholes. This study demonstrated that the sand filters used in the pre-treatment at both plants provided minimal to no improvement in raw water quality and increased water losses through backwashing. Suspended solids and microbiological quality often do not require treatment with the use of groundwater, and therefore application of sand filtration technology as pre-treatment component not clearly justified. Therefore, future considerations regarding the use of these pre-treatment components in relation to raw water quality dynamics should be taken into account.

Abstract: In arid and semi-arid ecological areas of Southern Africa, water resources face pressure due to low rainfall, droughts, high population growth, and inadequate infrastructure. The inhabitants of the Iishana system in Namibia depend on various traditional water sources to respond to water scarcity and droughts. With the anticipated new water infrastructural development and rehabilitation of existing ones, it is crucial to assess the quality of collected and stored water in the Iishana to manage water demand effectively. This study collected ten (10) water samples from the surface water bodies enclosed within the Iishana system for analysis during the drought period. Physico-chemical parameters such as electrical conductivity, turbidity, and dissolved oxygen content were measured on-site, while elemental and biological compositions were measured at the Namibia Water Corporation Ltd (NamWater). The test results were compared with the Namibian standard guidelines to determine compliance. To assess the water quality of the Iishana system, the cluster, correlation matrix, and factor analysis were used to examine the level of correlation among parameters using Minitab (21.2) and Grapher (20.2.321) software. The Water Quality Index (WQI) results in the 10 sampled pans range from 81.30 to 320.65, hence, classified as unsuitable for drinking. The abundance of cations is in the order: Na⁺> Ca²⁺>, Mg²⁺> K⁺ >Fe²⁺, whereas for anions is Cl^->SO₄^2->NO₃^->NO₂^-. The high level of Na⁺ and Ca²⁺ are due to the presence of inorganic salts of calcium and sodium compound in high quantity. The multivariate statistical analysis indicated that natural factors of soil weathering, mineral dissolution, and anthropogenic activities such as agriculture influence the sampled water in the Iishana. Therefore, the water cannot be used for human consumption without necessary treatment. This study presents the water quality and the most important pollution parameters of the water supply in the Iishana system.

Abstract: This study carried out an extensive analysis of flow and mobile bed material characteristics of River Baro in Niger State, Nigeria. Fifty-two years of daily discharge and water level data were collected and analyzed using the annual maximum streamflow. In addition, the test of the sediment materials collected at different locations along the river reach were analyzed. The sediment transport parameters such as fall velocity, Shield parameter, D₅₀, D₉₀, sediment density, Reynolds number, Grain-related Chezy coefficient, bed form factor, and shear stress were determined. The results show a declining rate of maximum annual stream flow under the studied flow regime. The generalized Extreme Value probability distribution model yields the best extreme flood estimation for different return periods. The bank-full discharge increases with an increasing return period. The dynamics of the bed materials show that the Shield parameter responsible for the initiation of motion of bed materials is in the range of (0.028 ≤ θ ≤ 0.19). The mean grain diameter follows (0.2 ≤ D_m ≤ 5) millimeters. The values of the Reynolds number exceeded x × 10⁵, where x is a positive integer. Hence, the flow in the River Baro is Turbulent under the consideration of annual maximum streamflow. The best sediment transport capacity formula for River Baro is the Meyer-Peter and Muller (M-P-M) model. Hence, the mobile bed materials are characterized as being gravel. The highest flood magnitude is in the order of 11800m³/s with a flood level of about 10m corresponding to a 50-year return period. The sediment transport capacity based on the M-P-M model for annual maximum streamflow of 2, 5, 10, 25, and 50-year return periods are 2.3, 2.17, 2.2, 2.27, and 2.33m²/s respectively. Multiplying each value by the river's width and converting the seconds to years will yield annual sediment transport capacity in m³/yr.

Abstract: Water distribution systems are critical to urban infrastructure, especially in regions facing water scarcity. This study focuses on the design of an innovative water distribution system with smart monitoring for Ongwediva Town in Namibia, addressing challenges due to population growth and climate variability. By integrating advanced sensors and smart technologies, the system measures real-time water level and monitors flow rate, thereby reducing water loss and operational costs. Calculations for key components, including the ultrasonic water level sensor, critical buckling load, pump size, and photovoltaic (PV) requirements, are presented. The water level sensor provides accurate distance measurements based on ultrasonic pulse timing, while the flow rate sensor achieves a calibrated flow of 1.2 l/min. Structural analysis of the water tower support yields a moment of inertia of 5.33×10^-9 m⁴, and a critical buckling stress of 1.37E×10^-7 N/m², confirming the suitability of mild steel. A 30 W pump powered by a 100 W PV system ensures reliable operation with minimal energy consumption. The daily energy requirement of 240 Wh and the adjusted requirement of 300 Wh highlight the importance of considering system efficiency in energy calculations. Accounting for a system efficiency of 80% ensures that the solar power system is adequately sized to meet operational demands without running into energy shortfalls. The system’s real-time data transmission allows for proactive leak detection and optimized water management, significantly improving sustainability. Testing and calibration confirm the system's reliability, offering a scalable model for other municipalities.

Abstract: The role of forestry in providing renewable, sustainable and environmentally friendly materials in engineering is increasingly being emphasized. This paper explores the recent advancements and diverse applications of sustainable forestry materials in several engineering sectors. A systematic and structured review was conducted, using literature from Web of Science, Scopus, ScienceDirect, and Google Scholar databases in the past decade. The results revealed that integration of sustainable forestry materials, such as timber, bamboo, cork, and engineered wood products like cross-laminated timber (CLT) and laminated veneer lumber (LVL), offers significant environmental benefits, including renewable sourcing, reduced carbon footprints, and versatile applications across various engineering sectors. Forestry sustainable materials provide viable replacements for traditional building materials in construction, automotive and aerospace. In addition, forestry materials are also being used in consumer goods, appreciating their aesthetics and performance properties. Furthermore, the results revealed that advanced processing techniques, such as thermal modification and chemical treatments, enhance the durability and performance of these materials for demanding applications. However, challenges like material degradation, high initial costs, unsustainable harvesting practices, and slow updates to building codes hinder their widespread adoption. Overcoming these barriers will require the development of standardized testing methods, improved processing technologies, greater market acceptance, and supportive policies, alongside advances in biotechnology. Therefore, sustainable forestry materials offer environmentally friendly and renewable alternatives in construction, automotive, and aerospace engineering. Advanced processing techniques enhance their durability, enabling their use in demanding applications while reducing carbon footprints.