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Academic staff development strategies in engineering fields of study: case study of Zimbabwe
(2013-06) Mhlanga, S.; Matope, S.; Mugwagwa, L.; Phuthi, N.; Moyo, V. S.
Higher education is the basic instrument of economic growth and technological advancement in any society. The economic meltdown in Zimbabwe which climaxed 2008 with an inflation level of 231million % exacerbated the brain drain. After the economic meltdown, Zimbabwe is in the process of rebuilding the quality of staff and the staffing levels in its higher education institutions. The challenge has been the decision on the mode of study: whether to go via taught masters or master's by research; where to allow the faculty members to study: in the region, or beyond; on a fulltime or on a part-time basis or on a split-site basis. These challenges have been due to the need to have a quick but quality programme of staff development, while maximising on the resources available for staff development. A survey was undertaken of the engineering related departments in Zimbabwe universities focusing on the existing staffing levels, their qualifications, current numbers undergoing study and their levels. The challenges faced by each institution from the administrative side and from the staff side are summarised. Recommendations on staff development strategies are given in conclusion.
Academic staff development strategies in engineering fields of study: case study of Zimbabwe
(2013-06) Mhlanga, Samson; Matope, Stephen; Mugwagwa, Lameck; Phuthi, Nduduzo; Moyo, Vincent S.
Higher education is the basic instrument of economic growth and technological advancement in any society. The economic meltdown in Zimbabwe which climaxed 2008 with an inflation level of 231million % exacerbated the brain drain. After the economic meltdown, Zimbabwe is in the process of rebuilding the quality of staff and the staffing levels in its higher education institutions. The challenge has been the decision on the mode of study: whether to go via taught masters or masters by research; where to allow the faculty members to study: in the region, or beyond; on a fulltime or on a part-time basis or on a split-site basis. These challenges have been due to the need to have a quick but quality programme of staff development, while maximising on the resources available for staff development. A survey was undertaken of the engineering related departments in Zimbabwe universities focusing on the existing staffing levels, their qualifications, current numbers undergoing study and their levels. The challenges faced by each institution from the administrative side and from the staff side are summarised. Recommendations on staff development strategies are given in conclusion.
Adsorption of Mercury by Pterocarpus Anglolensis: Study on Adsorption Isotherms and Kinetics
(Iranian Institute of Research and Development in Chemical Industries (IRDCI)-ACECR, 2022) Mapombere, Garainesu; Nyoni, Bothwell; Sibali, Linda L.; Chiririwa, Haleden; Seodigeng, Tumisang
The efficiency of Pterocarpus Anglolensis sawdust, an abundantly available waste product of the timber industry, capacity as an adsorbent for mercury was investigated. A series of batch experiments was carried out with experimental conditions of metal concentration, adsorbent concentration, pH, and contact time being changed. The concentration of the metal ion was deduced using spectrophotometric means. The adsorption efficiency was found to be pH-dependent with pH 4 being the optimum. 90 minutes was found to be the equilibrium time with particle size range 90-124 μm being the most efficient. Maximum adsorption of mercury was evaluated at 80.33 %. The experimental data was best modeled by the Freundlich isotherm and Pseudo second-order kinetic models. The calculated adsorption parameters are Kf = 0.0002 L/mg, bF = 3.0 and k2 = 0.00016 g/μg.min.
Advanced prediction of soil shear strength parameters using index properties and artificial neural network approach
(World Journal of Advanced Research and Reviews (WJARR), 2024-01-03) Habte, E.T.; Vadlamudi, S.; Ncube, M.; Muusha, P.
This study embarks on developing predictive models for soil shear strength parameters, cohesion (c) and angle of internal friction (ϕ), in Bishoftu town, employing Artificial Neural Networks (ANN). It aims at offering a cost-effective and time-saving alternative to traditional, often expensive, and labor-intensive laboratory methods. The research utilizes soil index properties such as Sand%, Fines%, Liquid Limit, Plastic Limit, and Plasticity Index to construct separate ANN models for c and ϕ. These models use a multi-layer perceptron network with feed-forward back propagation, varying the number of hidden layers to optimize performance. The study's dataset comprises 316 soil test results, encompassing both primary and secondary data, conforming to ASTM Standards. Soil cohesion and internal friction angle were determined using the direct shear box method. The models demonstrated remarkable success in predicting shear strength parameters, evidenced by correlation values of approximately 0.99 for cohesion and 0.98 for internal friction angle, surpassing the capabilities of existing empirical methods. Further examination of the models included comparison with existing correlation techniques and cross-validation using primary soil test data. This validation process confirmed the ANN method's superior accuracy and fit for predicting shear strength parameters over selected empirical methods. This research substantiates the efficiency of ANN in geotechnical engineering, particularly for areas with limited resources for extensive soil testing. It establishes ANN as a powerful, efficient tool for estimating soil shear strength parameters, with significant implications for future planning, design, and construction projects in similar environments.
Agility as a strategy in Zimbabwean manufacturing industries
(NUST, 2023) Muhla, T.; Mapindu, I.; Munyau, M.; Mhlanga, D.M.S.; Goriwondo, W.
Customer needs as well as requirements are always in a continuous state of flux and more often than not, Manufacturing Companies find themselves in a quandary as they try to meet these. The inherent ability of Manufacturing Companies to meet the ever-changing customer requirements is key in ensuring that they are able to gain a competitive advantage over their counterparts as well as succeed in this highly volatile market. The advent of the COVID-19 pandemic as well as its noticeably widespread effects also brought about disruptive effects within an already turbulent environment as the Zimbabwean Manufacturing Sector was not spared the scourge of the pandemic. The organizations thus have to gain resilience so as to be able to thrive as well as grow competitively within their sector. The purpose of this paper was to assess how applicable the Agile Strategy is within the Zimbabwean Manufacturing sector as well as to come up with effective methods by which the strategy could be adopted by more organizations within the sector. The key drivers to the implementation of the strategy within these sectors as well as challenges associated with the implementation were also reviewed in depth.
Air pollution control techniques for the cement manufacturing industry: A case study for Zimbabbwe
(2012) Zimwara, D.; Mugwagwa, L.; Chikowore, T.R.
Technological advancement has resulted in cement making companies being able to produce higher volumes compared to the past. However the higher production levels have also been largely labelled as the leading cause of pollution. The main sources of air pollution in the industry include excavation activities, dumps, tips, conveyer belts, crushing mills and kiln emissions. Harnessing appropriate technology for use in the cement industry could go a long way towards minimising on-site wastes and pollution. This review examines various options in practice for reducing pollution at cement manufacturing companies, which help ensure legislative compliance. By adoption of appropriate technology and computer modelling, industry will not only reduce production waste but also comply with legislation to do with environmental protection. The paper examines certain methods of pollution control used for air and looks at how computer modelling can be adopted for the classification, quantification and control of particulate matter; and how efficient energy use can contribute to better air quality. An analysis of gas stack emissions was done for a cement manufacturing company in Zimbabwe where compliance was investigated. Emissions samples were randomly selected at various points within the company and concentration of various emission constituents were analysed.
An attainable region approach for the recovery of iron and zinc from electric arc furnace dust
(2019) M.C. Siamea, M. C.; Kaomab, J.; Hlabanganac, N; Danhad, G.
This study investigated the application of the attainable region optimization technique to establish the optimum hybrid hydrometallurgical and pyro-metallurgical process conditions required to treat the electric arc furnace dust. The analysis of the results obtained showed that a combination of an agitation speed of 800 rpm, sodium hydroxide concentration of 8.0 mol/L and a leaching temperature of 80 °C were the optimum conditions for the hydrometallurgical process, while a roasting temperature of 1200 °C, carbon content of 35.27% and a roasting period of 36 h were the optimum conditions for the pyro-metallurgical process. The iron recovered from the dust was recycled in order to upgrade the iron content of the electric arc furnace charge, thereby reducing both process loses and process wastes.
An attainable region approach for the recovery of iron and zinc from electric arc furnace dust
(2019) Siame, M.C.; Kaoma, J.; Hlabangana, N.; Danha, G.
This study investigated the application of the attainable region optimization technique to establish the optimum hybrid hydrometallurgical and pyro-metallurgical process conditions required to treat the electric arc furnace dust. The analysis of the results obtained showed that a combination of an agitation speed of 800 rpm, sodium hydroxide concentration of 8.0 mol/L and a leaching temperature of 80 °C were the optimum conditions for the hydrometallurgical process, while a roasting temperature of 1200 °C, carbon content of 35.27% and a roasting period of 36 h were the optimum conditions for the pyro-metallurgical process. The iron recovered from the dust was recycled in order to upgrade the iron content of the electric arc furnace charge, thereby reducing both process loses and process wastes.
Analysis of the properties of a glass/sisal/polyester composite
(Springer Nature, 2021-01-11) Baloyi, R.B.; Ncube, S.; Moyo, M.; Nkiwane, L.; Dzingai, P.
Composites are gradually becoming an integral material for structural and manufacturing processes. Sisal fibre has the potential to be one of the leading reinforcement natural fibres, not only in Zimbabwe, but the world over for use in glass composites. This is mainly due to it being inexpensive, exhibiting a low density, high specifc strength, a high stiffness to weight ratio, non-toxicity, its abundance in Zimbabwe and its renewability. With an aim of coming up with a composite for partition board applications in the construction industry, five samples of sisal-glass composite were prepared with varying sisal fibre content and diferent layering techniques. Sisal fbres were pre-treated with 20% NaOH to enhance their crosslinking with the resin and reduce the chemical impurities such as lignin and waxes. Mechanical (fexural test, hardness, and tensile strength) and physical tests (density and water absorption) were conducted to analyse the properties of the composite. The results showed that treated sisal fibres had a higher breaking tenacity of 33.11 g/tex which is higher than untreated fibres with a breaking tenacity of 25.72 g/tex. The best properties were obtained in the sample with 4 layers of glass and 9 layers of sisal fibres using 200 ml of resin. The composite had a tensile strength of 57.60 MPa, fexural strength of 36 N/mm2, moisture absorption of 10% and a burning rate of 9.82 mm/ min. These results were then compared with those of the current partition boards in the market. It was noted that the composite was suitable for use in partition boards. Again, regarding cost, these composites are cheaper to produce at a rate of $11.33/m2 compared to the timber costing at $16/m2.
Application of amine-modified tannins gels as coagulants in wastewater treatment
(Research Square, 2024-08-28) Thelmmer, M.; Ncube, S.; Moyo, L.B.; Mamvura, T.A.; Danha, G.; Simate, G.S.; Tshuma, N.
Tannin (T) is an organic substance that may potentially be used as an inexpensive, environmentally friendly, and effective bio-coagulant to remove impurities from residential and commercial wastewater. In this study, bio-coagulants were prepared using tannins obtained from the wattle tree (Acacia mearnsii). The bio-coagulants were modified using formalin and optionally, ethanolamine (ETA) and ammonium chloride (NH 4 Cl) as amine sources through the Mannich Reaction scheme. Three coagulants were prepared, T-ETA modified tannin, T-NH 4 Cl modified tannin and a mixture of T-ETA: T-NH 4 Cl in molar ratio 1: 1. Aluminium sulphate [Al 2 (SO 4) 3], a metal-coagulant was also used as the standard for comparison. The three coagulants were tested at varied concentrations (500–1250 mg/L) using jar tests on laundry wastewater to see their effect on remediation of wastewater. A mixture of bio-coagulant T-NH 4 Cl and T-ETA was most effective with highest removal efficiencies for turbidity (94%), COD (85%), Total solids (87%) and nitrates (99%). For colour removal T-NH 4 Cl modified tannin showed the highest removal efficiency of 92%. The results support the use of cheaper and environmentally friendly amine modified tannin-based flocculants in laundry wastewater treatment as they showed less toxicity on the treated water.
Beverage Effluent Treatment Technology
(2016) Tshuma. J.; Maqhuzu, A.; Bhebhe, S.; Mudon, S.; Kaitano, H.; Mashanga, D.; Mpofu, C.; Tshuma, I.; Mkandla, C.K.
A detailed beverage effluent treatment technology was developed in a period of 4 months, using samples from an operating beverage plant. The total number of samples collected were 1304. The volume of the sample collected hourly was 500ml for 4 hours to give a composite sample. The plant operated continuously for 6 days a week and had two-12 hour shifts a day. The technology consisted of four water treatment methods combined consecutively which were chemical, physical, biological and physical treatment methods. The aim of developing the technology was to reduce the sCOD, TSS and pH parameters to the required environmental specification. The untreated beverage wastewater has high solids content, high organic matter, and low pH which need pretreatment before it is discharged into the municipal sewage treatment works. The developed technology reduced the high solid content, high organic load and adjusted the pH to the required Bulawayo Municipality environmental specifications. The average percentage reduction in sCOD and TSS was 91.1% and 90.6% respectively. The pH was adjusted to 8.05. The obtained results indicated that the developed technology was effective for treating beverage wastewater at ambient temperature to meet the quality of effluent that can be discharged into public water works.
Centralised Incubator Control System
(2016-01-27) Mtunzi, B.; Chamisa, M.; Madumbu, Z.; Gonye, N. R.; Nhenga-Mugarisanwa, F.
This paper presents an infant incubator system that protects and helps incubate a premature infant while in hospital. The device is economical, robust, and uses easily replaceable parts. It consists of a control mechanism that makes use of fans, a humidifier and a home heater rod to provide heat. The temperature and humidity were automatically controlled and maintained by a microcontroller. The incubator had a base designed to automatically weigh and log the infant’s weight. A Visual Studio interface was used to provide incubator chamber data and to evaluate the performance of the design. The system could weigh the weight of the infant as well as control the chamber temperature at 36.5°C and humidity at 40%. The system was able to maintain these conditions within a period of 5 seconds
Challenges and Drivers of Industrialist Propensity Among Chemical Engineering Students in STEM Institution in Zimbabwe: Towards A Conceptual Framework
(International Journal of Environment, Engineering and Education, 2024-04-24) Nkala, B.; Sibanda, V. M.; Ndhlovu, J.; Hobane, L.; Singh, S
NUST in Zimbabwe grapples with a significant challenge. Despite enrolling many students in chemical engineering, the nation lacks operational industries. Consequently, graduates often encounter difficulties securing employment or attachment placements post-graduation. This underscores the critical need to foster student entrepreneurship, encouraging innovation and idea generation. The study employed a mixed-methods research design to address this issue, combining qualitative and quantitative methodologies. The quantitative aspect utilized a quasi- experimental pre-test and post-test design, while the qualitative component involved conducting focus group interviews with chemical engineering students in the experimental group. The findings from both approaches complemented each other, providing a comprehensive understanding of the factors influencing entrepreneurial propensity among NUST chemical engineering students. Data collection involved distributing research instruments and questionnaires to NUST students and individuals associated with the mining and pharmaceutical industries. The collected data were then entered into an Excel spreadsheet, allowing for the recording of respondents' numbers alongside their respective responses. The study applied descriptive statistics to evaluate responses and their alignment with research objectives, revealing barriers to entrepreneurial inclination among NUST chemical engineering students, such as limited resources, risk aversion, inadequate entrepreneurial education, and cultural norms. Students benefited from personal motivation, a supportive educational atmosphere, networking opportunities, and exposure to innovative ideas. These factors nurtured self-determination, social networking, and an entrepreneurial mindset. To foster entrepreneurial spirit among NUST chemical engineering students, the study suggests educational reforms, mentorship programs, and potential policy changes create an enabling environment, empowering students to pursue entrepreneurship and contribute to economic growth.
Characterization, kinetics and thermodynamic evaluation of struvite produced using ferrochrome slag as a magnesium source
(South African Journal of Chemical Engineering, 2023-10-24) Moyo, L.B.; Simate, G.S.; Hobane, N.; Dube, C.
There is limited data on studies that have focused on the kinetics, thermodynamics, and characterization of struvite crystallization from alternative magnesium sources. This study focused on thermal analysis of struvite (produced using ferrochrome slag as a magnesium source) and the results indicated that the residual quantities of struvite were lower than the theoretical mass loss of struvite of 51.42%. When using ferrochrome slag (FCS) as the magnesium source, 47.9%, 47.4%, and 46.9% losses in mass were observed for heating rates of 5◦C/min; 10◦C/min and 15◦C/min respectively. The mean activation energies for struvite produced using FCS were deduced using isoconversional kinetic methods and ranged from 49.81to 56.20 kJ/mol which is very similar to the activation energies deduced using MgCl2. The study also focused on the surface morphology, and particle size of the final product at different pH and N:P ratios. The final particle size distribution of the product was significantly influenced by the solution pH. To improve the crystal growth kinetics for both MgCl2 and FCS, a high ratio of N:P molar ratios should be adopted. The product's highest median particle size was obtained using FCS as the magnesium source at a low pH. Median particle size increased with decrease in pH, at a pH of 7.5 the recorded median particle size was 96 µ m whilst, the lowest was 31 µ m at a pH of 9.5. The highest percent of fines (<10 µ m) was recorded at a pH of 9.5 using FCS as magnesium source in the metastable region of struvite precipitation whereas at a pH of 7.5 no fines (<10 µ m) were recorded. SEM images confirmed that the struvite underwent morphological changes when prepared with FCS in comparison to that produced using MgCl2. The surface morphology of the finished product demonstrated the presence of irregular shaped particles, due to presence of impurities. The kinetic data showed that struvite precipitation was limited by the chemical reaction step. Model fitting was used to determine the reaction control mechanism and the average activation energies obtained by four model free methods were FWO (56.2), KAS (51.67) Starink (49.61) and Tang (49.81) kJ/mol, indicating that the FWO method was the least accurate method. The thermodynamic data indicated that the thermal degradation of struvite crystals has a high degree of disorder, and the process is endothermic, irreversible, and non-spontaneous.
Cost of Quality as a Driver for Continuous Improvement - Case Study – Company X
(2013) Zimwara, D.; Mugwagwa, L.; Maringa, D.; Mnkandla, A.; Mugwagwa, L.; Ngwarati, T.T.
In the manufacturing, metal casting industry is one of the oldest basic principal and most important industries. The casting process is hindered by the occurrence of various defects. High casting reject levels and customer returns have a considerable adverse effect on productivity, delivery performance, customer satisfaction and employee morale. In addition excessive rejection reduces yield, wastes valuable raw materials and involves management time in problem solving. All foundry processes generate a certain level of rejection that is closely related to the type of casting, the processes used and the equipment available. This paper seeks to establish the extent to which cost of quality can impact on continuous improvement of the products and the relationship with the customers of the organization. To determine the cost of quality (COQ) at casting company X, the researchers used existing company records, publications and historical evidence of the company. The researchers utilized techniques such as, bar charts and tables in presenting and interpreting data. The above techniques have the ability to provide methods for collecting, presenting, and analysis and meaningfully interpret data. The research findings estimated the COQ to be 6.6% of sales revenue.
Design of a Control System for a Vending Machine
(Elsevier, 2020) Murena, E.; Sibanda, V.; Sibanda, S.; Mpofu, K.
Vending machines are available in many public places for vending of items like snacks, beverages, newspapers, tickets and smoking cigarettes Recently developed vending machine requires a control system to offer a variety of products to the general public. In this light, this paper, therefore, is aimed at developing a control system for the developed vending machine by developing various inputs required to make the machine function efficiently. The system controls and monitors the vending machine functions, namely: alarm system, product dispensing, refrigeration and payment system. The microcomputer capitalises on the evolution of high-performance processors and stable operating systems to implement control requirements. The project shall use intelligent vending machine input/output board to link other machine peripherals. The control system shall enable the machine to handle coin, mobile and point of sale terminal payment options. Implementation of the control system enhances flexibility in payment, remote machine monitoring and inventory control, and improved user experience through the integration of digital touch screen user interfaces and high-speed transaction processing
Design of a Dual Operating Mode Sheet Folding Machine.
(2013) Gwangwava, N.; Mugwagwa, L.; Ngoma, S.
A sheet folding machine that can be operated through hydraulics by two hydraulic cylinders or manually (with the cylinders disengaged) was designed. The design need emanated from the strained national electrical grid system that has recently seen industrialists and households in Zimbabwe experiencing major power cuts. The machine enables manufacturers to shedule heavier jobs during periods when power supply is up and lighter jobs during power cut periods hence run their workshops throughout the daily production shifts. The two hydraulic cylinders can be disengaged from the machine’s folding beam so that manual operation can be done through a manual clamping lever system. The folding force at full capacity is 294.6 KN (29.46 Ton), total bending length of 1.8 m and working height of 1 m. The folding force decreases significantly in manual operating mode to 500 N, considering that on average an operate can manually exert that force. A student version of Simulation X 3.5 was used to simulate the hydraulic operation of the machine
Determining an optimal interstitial filling condition: An Attainable Region approach
(Elsevier, 2018) Hlabangana, N.; Madiba, M.S.; Bhondayi, C.; Mguni, Nonhlanhla G.; Danha, Gwiranai
In this article, we present yet another application of the Attainable Region (AR) method to data from a laboratory scale milling of a low grade gold ore. In this particular case, we investigate how to optimize the amount of material in a desired size class for a scenario where the boundaries of the desired size class of interest are changed. The AR approach has never been applied in such a scenario before. Using a mono sized feed of − 1700 + 850 μm, two desired product size classes of interest (− 850 + 150 μm and − 150 + 75 μm) are selected in order to determine the optimum interstitial filling (U) to be used in the mill. Two different values of U, 1.75 and 1.0 respectively, are obtained as optimal. Our results also show that optimal operating conditions are different for different objective functions. We demonstrate that the AR may be used to specify optimal conditions that may be used for particle size reduction processes. We also illustrate how an AR boundary for optimization purposes can in certain cases be extended using the ‘mixing principle’.
Determining Optimum Wet Milling and Leaching Parameters for Maximum Recovery of Gold
(Research Publish Journals, 2017-12) Mguni, Nonhlanhla G.; Bhebhe, Siboniwe; Danha, Gwiranai; Tshuma, Joel; Hlabangana, N.
Abstract: The comminution and leaching unit operations play a vital role in the extraction process of valuable minerals from ores. Historical research efforts have focused more on optimizing these two unit operations individually rather than as an entire integrated process. The approach employed in modern day research is now driven by the process intensification philosophy. Process intensification detects that developing an integrated approach to mineral processing systems and flow sheets leads to improved efficiency of the overall process and can help attain optimum recovery and a reduction in energy and material costs. In this article, we present laboratory scale batch grinding and leaching profiles of a mono-sized gold ore sample (-1700 + 850 μm). The sample was obtained from a run-of-mine (ROM) ore of one the leading gold processing plants in South Africa. Various combinations of grinding media fill level and ball size were investigated, showing that breakage is more pronounced for the larger ball sizes tested. We also found that using a higher media filling (J = 30%) and a larger media size (30 mm) consumed more energy with less gold recovered during a 24 hour leaching period, compared to when a smaller J of 15% and 20 mm media was used. Our results show that efficient application of energy is vital and maximum profit is a complex function of energy usage and particle size. Keywords: gold, Historical research, mineral processing, energy, material costs.
Development and Characterisation of a Nanocomposite Membrane Using Polyethersulphone and Graphene Oxide-Magnetite Nanoparticles for Rejection of Chromium Hexavalent Ions from Tannery Wastewater
(2018) Gadlula, S.; Ndlovu, L.N.; Ncube, L.K.
Polyethersulphone (PES) polymer blended with Graphene Oxide (GO) and magnetite ( nano-composite was synthesized using an immersion precipitation process for the filtration of chromium hexavalent ions from leather processing waste water. PES is a synthetic polymer with good chemical resistance, wide pH range (2-13) as well as good mechanical and thermal properties. However, it is hydrophobic and prone to fouling hence its limitations in aqueous separation processes. In order to improve hydrophilicity, porosity, permeability and strength properties of the polymeric membrane, GO was synthesized from coal via a modified Hummers Method and then blended with anhydrous ferrous chloride to form Graphene oxide/ magnetite () hybrid nano-particles. To assess the performance of the membrane pure water flux, Equilibrium Water Content (EWC) and tensile strength test was measured. Structural analysis involved porosity measurement. The filtration efficiency of the membranes was found by testing the waste water for chromium ion concentration before and after filtration. It was established that both the physical properties and chromium ion rejection improved with increase in polymer concentration and addition of hybrid nano-particles.

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