Industrial and Manufacturing Engineering Publications

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DEVOLUTION, NEIGHBOURHOOD FORM AND STRUCTURE AND TRANSFORMATIONS IN BULAWAYO, ZIMBABWE, 2018-2021
(JUSIRZ, 2024-06) Magwaro-Ndiweni, L.; Fayayo, R.
With the government of Zimbabwe channelling devolution funds through the Minister for Provincial Affairs and Devolution, the paper challenges this channel towards ‘Si Ye Pambili’ the city’s motto, that is translated as ‘Let us go Forward’. The question is who is being taken where, by whom, and how is it going to happen and when. Zimbabwe has selected devolution as the mechanism within that to achieve decentralisation. The paper seeks to understand the Zimbabwe National Devolution and Decentralisation Policy. Through analysing the policy in the context of local government amendment bill and the constitution of Zimbabwe. In the contexts of neighbourhood organisation structures, neighbourhood management and neighbourhood fiscal resource allocation and neighbourhood information access. The growth of Bulawayo City has been largely unsuccessful, the decision-making process has been met with fluctuations in funding and questionable levels of support from central government and the communities. Devolution is therefore an important opportunity to re-examine how the devolution of powers and decision making to neighbourhoods, through the community sector, could be achieved. Using lucid review of literature, informed by theories, and qualitative, descriptive research approaches the paper discusses issues of mechanisms for neighbourhood governance. The paper concludes by saying that, although new mechanisms for neighbourhood governance would be required, they would have to vary according to geography and local requirements going beyond consultation processes.
Enhanced technique for removal of methylene blue dye from water using Luffa microcrystalline cellulose
(South African Journal of Chemistry, 2024-02-11) Ngwenya, V.; Ndebele, N.R.; Ncube, L.K.; Nkomo, N.Z.; Gadlula, S. and Ndlovu, L.N.; Ndlovu, L.N.
Methylene blue, a toxic and carcinogenic azo dye, is being discharged as industrial effluent to the environment posing a threat to human health and marine life. Different methods have been developed to alleviate these problems associated with methylene blue. In this work, the adsorption of methylene blue dye was studied using Luffa microcrystalline cellulose (Luffa MCC) under different physicochemical conditions. Luffa MCC was synthesized through a hydrolysis process which entails the extraction of alpha-cellulose from Luffa cylindrica fibers followed by acid treatment for microcrystallisation. The α cellulose extraction was achieved through a pretreatment process of Luffa fibers in NaOH followed by bleaching with H 2 O 2 and finally hydrolysis of α-cellulose using HCl. Different methods were used to characterize the properties of Luffa fibers and Luffa MCC. The morphological structure was studied through the use of Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Energy Dispersive X-ray spectroscopy (EDS), and Thermogravimetric Analyzer (TGA). Adsorptive removal of methylene blue was studied at different pH, initial dye concentration, adsorbent dosage, temperature and contact time. Maximum adsorption efficiency of 99.69%. of methylene blue was achieved at pH 10 in 180 min. The adsorption kinetics suggests a chemisorption process since it was favoring the pseudo-second-order reaction while the isotherm was best described by Langmuir model which suggests that it was monolayer sorption at a homogenous surface. It can be concluded that adsorption properties were significantly improved after the modification of Luffa fibers.
Taguchi Full Factorial Design of Experiments Optimisation of Cutting Parameters for Energy Efficiency and Surface Roughness during the Dry Turning of EN19 Material
(Scientific Research Publishing, 2024-05-30) Tayisepi, N.; Mnkandla, A.N.; Tigere, G.; Gwatidzo, O.; Mutenhabundo, W.; Ndala, E.; Wagoneka, L.M.
During metal machining, the satisfactoriness of cost-quality-time matrix convergence effectively depends on the supreme selection of cutting parameters. This study investigated the energy use minimisation and quality surface generation through optimised cutting parameters application, as sustainability enhancement during dry turning of EN19 material. Cutting parameter optimisation is a serious challenge confronting the machining industry as they strive to achieve low energy use and better component quality generation from their operations. The utility material, EN19, is a medium-carbon low alloy steel which typically gets applied in the manufacturing of multiple profiled cylindrical machine tool, rail locomotives and motor vehicle component parts, inter alia. Taguchi Full Factorial experimental plan was used to organise the empirical experiments. ANOVA and the main effects plot signal-to-noise ratio optimisation analysis were utilised in the study to establish the influence of process parameters on the response parameters—surface roughness and energy use. The aim was to investigate and determine the correlation of the machining strategy parameters with the outcome of low energy use and quality surface texture of the components as the cutting parameters were varied, and optimised for minimum surface roughness and energy use. Results of the extensive experimental study, produced optimum cutting speed, rake angle variation and feed rate which respectively influence the response parameters positively for energy use minimisation and improved surface quality. Validation experiments confirmed model findings.
OPTIMISATION OF MACHINING PARAMETERS FOR SURFACE ROUGHNESS, POWER CONSUMPTION AND OTHER RESPONSES DURING THE CNC LATHE DRY MACHINING OF EN24 ALLOY STEEL
(The Iraqi Journal for Mechanical and Material Engineering, 2024-06) Tayisepi, N.; Simbanegavi, M.
Design and analysis of optimisation protocols used for performance enhancement of machining based components manufacturing is currently an active area of machining science. This experimental investigation research deals with determining and optimising the effects of three input parameter metrics on the performance realisation of good surface quality output and energy consumption during the dry machining process of EN 24 steel material by turning on the CNC lathe. The input parameter metrics considered were cutting speed, depth of cut and feed rate. The study, employed Taguchi full factorial design approach in planning the experimental process and estimate the effects of the input metrics on the response; three phase digital energy meter to capture electrical power consumption data online; offline recorded surface roughness data and used Minitab 18 statistical software analysis of variance to assess the influence of cutting parameters on the response parameters, and the Signal to noise ratio main effects plot as the optimisation tool for the various response parameters. The paper aimed to determine the appropriate cutting parameter settings required on the lathe machine in order to produce EN 24 components of better surface quality at minimum energy expenditure. The experimental data analysis results established the optimum operating conditions at varied cutting parameter settings with respect to the different response parameters and the results were presented for the surface roughness, material removal rate and specific cutting energy use.
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.

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