Industrial and Manufacturing Engineering Publications

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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.
Effects of Palladium Chloride Concentration on the Nanoscale Surface Morphology of Electroless Deposited Palladium Thin Film
(The Electrochemical Society, 2021-05-27) Mpofu, B.S.; Mangosho. T.; Rugwejera, T.; Munjeri, K.; Dera, T. O.; Gutu, T.
Understanding the effects of thin film electroless deposition parameters at nanoscale is crucial for complete understanding and control of the thin film deposition process. In this study, we investigated and optimized the effect of PdCl2 precursor concentration on the nanoscale surface morphology of electroless deposited Pd thin film. The FESEM characterization of plain substrates showed that the dominant features of plain alumina substrates were terraces, steps and bumpy microstructures and the final surface morphologies of the deposited Pd thin film was strongly dependant on the surface morphologies of the substrate. FESEM characterization results of seeding technique displayed a thin film of Pd nanoparticles on the surface of the alumina substrate. The number of times that the seeding process was carried out was optimized at five seeding times using hydrazine as a reducing agent. FESEM characterization revealed that the nanoscale surface morphology of the Pd thin film was strongly dependent on PdCl2 precursor concentration. Three types of secondary nanoscale surface morphologies formed were nanorods, nanoflakes and flowerlike Pd nanostructures at various concentrations. The nanoflake surface density was strongly dependent on PdCl2 precursor concentration. Results of this research provided a foundation and method to tailor the nanoscale surface morphology to the specific requirement of surface dependent processes or reactions.

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